Investigation of Anterior Segment and Pupillometry Changes with Sirius Corneal Topography in Chronic Smokers

Investigation of Anterior Segment and Pupillometry Changes with Sirius Corneal Topography in Chronic Smokers | Research Square window.SnipcartSettings = { analytics: { enabled: false } }; (function() { var accessVector = localStorage.getItem('access_vector') || ''; window.dataLayer = window.dataLayer || []; if (accessVector) { window.dataLayer.push({ user: { profile: { profileInfo: { snid: accessVector } } } }); } })(); (function(w,d,s,l,i){w[l]=w[l]||[];w[l].push({'gtm.start':new Date().getTime(),event:'gtm.js'});var f=d.getElementsByTagName(s)[0],j=d.createElement(s),dl=l!='dataLayer'?'&l='+l:'';j.async=true;j.src='https://www.googletagmanager.com/gtm.js?id='+i+dl;f.parentNode.insertBefore(j,f);})(window,document,'script','dataLayer','GTM-K279D39R'); Browse Preprints In Review Journals COVID-19 Preprints AJE Video Bytes Research Tools Research Promotion AJE Professional Editing AJE Rubriq About Preprint Platform In Review Editorial Policies Our Team Advisory Board Help Center Sign In Submit a Preprint Cite Share Download PDF Research Article Investigation of Anterior Segment and Pupillometry Changes with Sirius Corneal Topography in Chronic Smokers Ramazan Birgul, Ahmet Kursad Sakallioglu This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-4155863/v1 This work is licensed under a CC BY 4.0 License Status: Posted Version 1 posted You are reading this latest preprint version Abstract Purpose Chronic smoking is still one of the world’s leading health problems. In addition to the systemic effects of cigarette smoking, ocular effects are also present, as ocular structures are a mucosal surface. The aim of this study was to investigate the effects of chronic cigarette smoking on the anterior segment and pupil using Sirius corneal topography. Materials and Methods The study included 70 chronic smokers in the experimental group and 72 non-smokers in the control group. Central corneal thickness (CCT); corneal volume (CV); anterior chamber depth (ACD); anterior chamber angle (ACA); anterior chamber volume (ACV); first non-contact tear breakup time (NCTBUT); mean NCTBUT; meibography; scotopic, mesopic and photopic pupil sizes; and dynamic pupil sizes at 0, 1, 2, 4, 6, 8 and 10 s were measured. Results There were no statistically significant differences between the chronic smoker group and the control group in terms of age; gender; CCT; CV; ACD; ACA; ACV; first NCTBUT; mean NCTBUT; or dynamic pupillometry at 2, 4, 6, 8 and 10 s. There were statistically significant differences between the groups in terms of meibography; scotopic, mesopic and photopic static pupillometry; and dynamic pupillometry at 0 and 1 s. Conclusion In this study, only the meibomian gland was affected among the anterior segment structures. Changes in other anterior segment structures were not significant. On the pupil, chronic smoking increased the scotopic, mesopic and photopic pupil diameter and the early stages of dynamic pupillometry. This indicates that cigarette smoking results in nicotinic autonomic neuropathy on the pupil. Introduction Chronic smoking is still one of the leading global health problems. It contains about 4000 different substances, which have many effects on the body, especially cancer and lung diseases ( 1 ). In ophthalmological practice, some studies have shown that chronic smoking causes retinal vein thrombosis, optic neuropathy, dry eye, Grave’s ophthalmopathy and macular degeneration ( 2 – 4 ). The ocular effects of cigarette smoking occur in various ways. Thrombosis is caused by increasing platelet aggregation in the blood, increasing free oxygen radicals and the toxic effect of cigarette smoke directly on the ocular surface. Therefore, the eye, which is a mucosal surface, is one of the most vulnerable organs to cigarette smoke ( 5 , 6 ). Although some studies have reported that cigarette smoke causes dry eye and meibomian gland dysfunction, other studies claimed the opposite ( 7 – 10 ). In addition, some studies have reported that cigarette smoke decreases CCT, while other have reported that it does not affect CCT ( 7 , 11 ). The most important reason for cigarette addiction is the nicotine content. Nicotine is converted into cotinine, its main component, in the blood, and this has systemic effects. Generally, cotinine affects the sympathetic system and increases heart rate and blood pressure. It affects the eye by changing the diameter of the pupil. While the expected effect of cotinine is dilation of the pupil diameter ( 12 , 13 ), some studies have reported that it narrows the pupil diameter ( 14 , 15 ). These contradictory results in chronic smokers indicate the need for a more comprehensive study. The aim of this study was to evaluate the anterior segment and pupillary changes in chronic smokers using Sirius corneal topography. Materials and Methods This prospective, cross-sectional study adhered to the principles of the Declaration of Helsinki. Informed consent was obtained from all participants. After obtaining local ethical approval, 70 right eyes of 70 chronic smokers and 72 right eyes of 72 healthy controls with no smoking history were included in the study. Subjects who regularly smoked at least one packet of cigarettes per day for the last 5 years were included in the study group. The subjects in the control group had not smoked or been exposed to passive smoking throughout their lives. Exclusion criteria for both the chronic smoker group and the control group were spherical and cylindrical refractive error over 1 dioptre, contact lens use, use of any topical drops or any history of ocular surgery or disease. Levels of cotinine, the main metabolite of nicotine in the blood, gradually increase during the day ( 16 ). Therefore, all participants were asked not to smoke for 24 hours. Best corrected visual acuity was measured in all subjects. Anterior segment and fundus examinations and a detailed ophthalmological examination were performed. Measurements were conducted with Sirius corneal topography (CSO, Firenze, Italy) by the same technician under the same lighting conditions. To eliminate the possible effects of environmental factors and diurnal variations, all measurements were taken at the same time of the day. All subjects underwent three consecutive measurements. CCT; CV; ACD; ACA; ACV; first NCTBUT; mean NCTBUT; meibography; scotopic, mesopic and photopic pupil sizes; and dynamic pupil sizes at 0, 1, 2, 4, 6, 8 and 10 s were measured. Meibography Meibography was performed with a Scheimpflug camera Placido topography device (Sirius, CSO, Firenze, Italy). Patients’ upper and lower lids were everted with a cotton applicator. The imaging included all meibomian glands and was repeated three times by the same technician under the same illumination. The images were evaluated using the computer-aided Phoenix Meibography Imaging Module. However, the meibomian gland borders had to be drawn manually. The missing area score was calculated automatically with a predetermined degree. These values expressed the percentage of lost area as follows: (0) 0%, ( 1 ) 75% ( 17 ). Pupillometry Sirius corneal topography (CSO, Firenze, Italy) Phoenix v2.1 software was used for pupillometry. For static pupillometry, scotopic pupil diameter was measured at 0.4 lux illumination after 5 m of dark adaptation. Afterwards, mesopic pupil diameter at 4 lux illumination and photopic pupil diameter at 40 lux illumination were measured. After static pupillometry, dynamic pupillometry was performed at 500 lux illumination at 0, 1, 2, 4, 6, 8 and 10 s. Statistical Analyses Statistical analyses were performed using IBM SPSS (IBM Corp., Armonk, NY, USA) version 20.0. Numerical descriptive statistics are presented as means and standard deviations for normally distributed variables. Descriptive statistics of categorical variables are presented as percentages. The Kolmogorov–Smirnov test was used to assess the normality of the data. The independent samples t-test was used to compare two independent groups. The significance level was p < 0.05. Results Of the 70 subjects in the chronic smoker group, 47 were male (67.1%), and 23 were female (32.9%). In the control group, subjects were male (63.9%), and 26 subjects were female (36.1%). The mean age of the study group was 44.7 ± 9.6 years (range: 23–67), while the mean age of the control group was 46.4 ± 11.2 years (range: 19–69). When both groups were compared in terms of gender and age, there were no statistically significant differences between them (Table 1 ). Table 1 Relationship of gender and age with smoking status Chronic Smoker Group Control Group P Male 47 (67.1%) 46 (63.9%) 0.726 Female 23 (32.9%) 26 (36.1%) Age 44.7 ± 9.6 46.4 ± 11.2 0.342 Kolmogorov–Smirnov, Independent Sample Test *p < 0.05 In terms of anterior segment parameters, CCT was 538.6 ± 29.4 µ in the chronic smoker group and 542.9 ± 29.5 µ in the control group. When other anterior segment parameters were analysed, CV was 55.1 ± 3.8 mm³ in the chronic smoker group and 55.8 ± 3.4 mm³ in the control group, ACD was 2.8 ± 0.3 mm in the chronic smoker group and 2.8 ± 0.4 mm in the control group, ACA was 44.3 ± 4.5° in the chronic smoker group and 43.7 ± 6.1° in the control group and ACV was 159.5 ± 32.1 mm³ in the chronic smoker group and 153.3 ± 39.2 mm³ in the control group. No significant differences were found between the chronic smoker and control groups in terms of CCT, CV, ACD, ACA or ACV (Table 2 ). Table 2 Relationship of CCT, CV, ACD, ACA and ACV with smoking status Chronic Smoker Group Control Group P CCT 538.6 ± 29.4 µ 542.9 ± 29.5 µ 0.385 CV 55.1 ± 3.8 mm³ 55.8 ± 3.4 mm³ 0.240 ACD 2.8 ± 0.3 mm 2.8 ± 0.4 mm 0.285 ACA 44.3 ± 4.5° 43.7 ± 6.1° 0.496 ACV 159.5 ± 32.1 mm³ 153.3 ± 39.2 mm³ 0.302 Kolmogorov–Smirnov, Independent Sample Test *p < 0.05 When ocular surface parameters were analysed, first NCTBUT was 13.3 ± 5.0 s in the chronic smoker group and 13.9 ± 4.3 s in the control group, mean NCTBUT was 13.6 ± 4.7 s in the chronic smoker group and 14.4 ± 3.7 s in the control group and meibography was 7.9 ± 5.2% in the chronic smoker group and 1.2 ± 1.3% in the control group. When the groups were compared, there were no significant difference between them in terms of first NCTBUT and mean NCTBUT, but there was a significant difference in terms of meibography (Table 3 ). Table 3 Relationship of first NCTBUT, mean NCTBUT and meibography with smoking status Chronic Smoker Group Control Group P First NCTBUT 13.3 ± 5.0 s 13.9 ± 4.3 s 0.389 Mean NCTBUT 13.6 ± 4.7 s 14.4 ± 3.7 s 0.269 Meibography 7.9 ± 5.2% 1.2 ± 1.3% 0.000 Kolmogorov–Smirnov, Independent Sample Test *p < 0.05 When the groups were analysed in terms of static pupillometry, the pupil size was 5.5 ± 1.0 mm in the chronic smoker group and 5.1 ± 0.8 mm in the control group under scotopic conditions, 5.5 ± 1.0 mm in the chronic smoker group and 5.0 ± 0.9 mm in the control group under mesopic conditions and 4.8 ± 1.0 mm in the chronic smoker group and 4.2 ± 0.9 mm in the control group under photopic conditions. There were statistically significant differences in the scotopic, mesopic and photopic pupil sizes between the groups. Dynamic pupillometry was 3.1 ± 0.5 mm in the chronic smoker group and 2.8 ± 0.5 mm in the control group at 0 s, 3.8 ± 0.6 mm in the chronic smoker group and 3.6 ± 0.6 mm in the control group at 1 s, 4.3 ± 0.7 mm in the chronic smoker group and 4.0 ± 0.6 mm in the control group at 2 s, 4.7 ± 0.8 mm in the chronic smoker group and 4.5 ± 0.7 mm in the control group at 4 s, 5.0 ± 0.8 mm in the chronic smoker group and 4.8 ± 0.8 mm in the control group at 6 s, 5.2 ± 0.8 mm in the chronic smoker group and 5.0 ± 0.8 mm in the control group at 8 s and 5.3 ± 0.9 mm in the chronic smoker group and 5.1 ± 0.9 mm in the control group at 10 s. When the groups were compared, significant differences were found for dynamic pupillometry at 0 and 1 s but not at 2, 4, 6, 8 or 10 s (Table 4 ). Table 4 Relationship of scotopic, mesopic and photopic as well as dynamic pupillometry pupil sizes at 0, 1, 2, 4, 6, 8 and 10 s with smoking status Chronic Smoker Group Control Group P Scotopic 5.5 ± 1.0 mm 5.1 ± 0.8 mm 0.004 Mesopic 5.5 ± 1.0 mm 5.0 ± 0.9 mm 0.001 Photopic 4.8 ± 1.0 mm 4.2 ± 0.9 mm 0.000 Dynamic 0 s 3.1 ± 0.5 mm 2.8 ± 0.5 mm 0.007 Dynamic 1 s 3.8 ± 0.6 mm 3.6 ± 0.6 mm 0.007 Dynamic 2 s 4.3 ± 0.7 mm 4.0 ± 0.6 mm 0.056 Dynamic 4 s 4.7 ± 0.8 mm 4.5 ± 0.7 mm 0.074 Dynamic 6 s 5.0 ± 0.8 mm 4.8 ± 0.8 mm 0.150 Dynamic 8 s 5.2 ± 0.8 mm 5.0 ± 0.8 mm 0.121 Dynamic 10 s 5.3 ± 0.9 mm 5.1 ± 0.9 mm 0.176 Kolmogorov–Smirnov, Independent Sample Test *p < 0.05 Discussion We compared the chronic smoker group with the control group with the help of the results we obtained in this study. There were no statistically significant differences between the groups in terms of age; gender; CCT; CV; ACD; ACA; ACV; first NCTBUT; mean NCTBUT; or dynamic pupillometry at 2, 4, 6, 8 or 10 s. There were statistically significant differences between meibography; scotopic, mesopic and photopic static pupillometry; and dynamic pupillometry at 0 and 1 s. Smoking has various systemic and ocular effects. It mainly causes lipid peroxidation in the vascular wall and platelet adhesion and aggregation. This results in atherosclerosis. It also increases proinflammatory cytokines such as calcitonin decreases anti-inflammatory cytokines such as ascorbic acid. All these systemic effects also affect ocular structures (5,8,18). Anterior segment structures such as the cornea, which is avascular, are especially affected by hypoxia and ischaemic conditions ( 19 ). In addition, it is known that free oxygen radicals are produced by the direct toxic effect of cigarette smoke and that smoking changes the structure of proteins in ocular structures (20). Knuutinen et al. ( 21 ) found that smoking decreased CCT by affecting collagen among these proteins. However, Ilhan et al. ( 22 ) reported that CCT did not change in their study. In our study, it was observed that CCT was not significantly different between the groups. No study in the literature has been conducted on the status of anterior segment elements other than CCT, CV, ACD, ACA and ACV in smokers. In our study, no significant differences were observed between the groups in terms of CV, ACD, ACA or ACV. This shows that although some studies have shown that smoking changes the proteins in ocular structures at the histological level, this does not significantly change the corneal and anterior segment structures anatomically. The mucosal surface of the body most exposed to cigarette smoke is the ocular surface ( 23 ). Since this surface is in direct contact with cigarette smoke, the tears and meibomian gland are affected. Cigarette smoke shows its effects by peroxidation on the lipid layer in tears and by increasing anti-inflammatory cytokines and hyperkeratinisation of the meibomian glands ( 10 ). In the studies in which tear parameters were analysed in the literature, quite contradictory results have been found in terms of the Schirmer and BUT tests. While some studies stated that parameters such as Schirmer and BUT decreased, others found that these parameters were not affected by smoking ( 6 – 8 , 24 ). Since these studies were generally performed with the traditional BUT test, the non-contact method was used in our study, making the result more objective. In our study, there were no significant differences for the first and mean NCTBUTs between the groups. However, meibography results were significantly impaired in smokers compared to the control group. Smoking has been shown to cause meibomian gland dysfunction in other studies ( 10 , 25 ). This shows that although smoking causes meibomian gland dysfunction, lipid peroxidation on the tear layer is not as high as thought, and dysfunction of the meibomian glands does not affect tear quality. The effect of smoking on the pupil is mainly caused by nicotine. In the blood, nicotine turns into cotinine, its active metabolite, by binding to acetylcholine receptors ( 16 , 26 ). Since there are approximately 4000 chemical substances in cigarettes, Fernandes et al. ( 14 ) investigated cigarette substances other than nicotine to determine their effects on the pupil and found that no substance other than nicotine affected the pupil ( 14 ). Narrowing and dilation of the pupil occurs by the autonomic nervous system with the help of the sympathetic and parasympathetic systems. While the pupil dilates with the help of the sympathetic system and dilator muscles, it narrows with the help of the parasympathetic system and constrictor muscles. Nicotine affects the whole body by activating the sympathetic system, especially by increasing blood pressure by vasoconstriction, but its effects on the pupil are variable. The expected effect is in the direction of pupil dilation due to the sympathetic effect ( 13 ). While pupil dilation has been reported in some studies, pupil narrowing has been reported in other studies ( 13 , 15 , 23 , 27 ). This contradictory situation may be due to the effects of acute versus chronic smoking. Sobacı et al. ( 28 ) reported that nicotine narrowed the pupil in acute period and dilated the pupil in the chronic period. Köktekir et al. ( 15 ) found that the mesopic pupil size was smaller in smokers in their study. However, since they performed this measurement 2 hours after smoking, they attributed this finding to the acute effect of smoking. All these pupillary responses may be the result of nicotine-induced autonomic neuropathy ( 28 , 29 ). In our study, the pupil was evaluated in detail, and all functions were analysed by static and dynamic pupillometry. In the chronic period, we found that the pupil dilated at 0 and 1 s of scotopic, mesopic, photopic and dynamic pupillometry. This result is similar to Sobacı et al.’s ( 28 ) finding that the pupil dilates in the chronic period. In the following dynamic 2, 4, 6, 8 and 10 s, pupil sizes were found to be larger in chronic smokers, but these differences were not statistically significant. This study had some limitations. Firstly, in the chronic smoker group, the duration of smoking and the number of packs smoked per day were questioned, which did not help us to examine whether there was a significant difference between chronic smokers in terms of duration and amount of smoking. Secondly, the nicotine level in the blood of the subjects at the time of measurement was not analysed. Future studies could investigate whether this has any effect on the results. Conclusion As smoking has effects on the whole body, it also has ocular effects. Since the anterior segment, unlike other ocular structures, is exposed to the direct toxic effects of cigarette smoke, it is the most affected part of the eye. In this study, only the meibomian gland was affected among the anterior segment structures. Although the meibomian gland plays a role in the production of tears, the direct toxic and systemic effects of smoking did not affect tear quality. The effects on the pupil were analysed for chronic smokers. Static pupillometry and dynamic pupillometry showed a significant increase in pupil diameter in the early periods and a non-significant increase in the later periods, indicating the development of nicotinic autonomic neuropathy on the pupil. Declarations Author Contribution R.B. wrote the main manuscript text and AKS prepared tables. All authors reviewed the manuscript References Van der Vaart H, Postma DS, et al. Acute effects of cigarette smoke on inflammation and oxidative stress a review. Thorax 2004;59:713–721. 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Niger J Physiol Sci 2007;22:33–36. Mantelli F, Giordano MM, Macchi I, Lambiase A, Bonini S. The cellular mechanisms of dry eye: pathogenisis to treatment. J Cell Physiol 2013;228:2253–2256. Knuutinen A, Kokkonen N, Risteli J, et al. Smoking affects collagen synthesis and extracellular matrix turnover in human skin. Br J Dermatol 2002;146:588–594. Ilhan N, et al. Effects of smoking on central corneal thickness and the corneal endothelial cell layer in otherwise healthy subjects. Eye Contact Lens 2016;42(5):303–307. Latif N, Naroo SA. Transient effects of smoking on the eye. Cont Lens Anterior Eye 2022;45(5):101595. Gabela Merino M, Gonzalez Garcia MJ, et al. Dry eye signs and symptoms in hydrogel contact lens wearers: relation to smoking habit. Arch Soc Esp Oftalmol 2003;78:543–548. Ağın A, Kocabeyoğlu S, Çolak D, İrkeç M. Ocular surface, meibomian gland alterations, and in vivo confocal microscopy characteristics of corneas in chronic cigarette smokers. Graefes Arch Clin Exp Ophthalmol 2020;258(4):835–841. Dani JA. Neuronal nicotinic acetylcholine receptor structure and function and response to nicotine. Int Rev Neurobiol 2015;124:3–19. doi: 10.1016/bs.irn.2015 Lie TC, Domino EF. Effects of tobacco smoking on the human pupil. Int J Clin Pharmacol Ther. 1999;37(4):184–188. Sobacı G, Erdem U, Gundoğan FÇ, Musayev S. The effect of chronic smoking on the pupil and photostress recovery time. Ophthalmic Res 2013;49(3):167–170. Bremmer FD, Smith SE. Pupil abnormalities in selected autonomic neuropathies. J Neuroophthalmol 2006;26:209–219. Additional Declarations No competing interests reported. Cite Share Download PDF Status: Posted Version 1 posted You are reading this latest preprint version Research Square lets you share your work early, gain feedback from the community, and start making changes to your manuscript prior to peer review in a journal. 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Also discoverable on Platform About Our Team In Review Editorial Policies Advisory Board Help Center Resources Author Services Accessibility API Access RSS feed Manage Cookie Preferences © Research Square 2026 | ISSN 2693-5015 (online) Privacy Policy Terms of Service Do Not Sell My Personal Information {"props":{"pageProps":{"initialData":{"identity":"rs-4155863","acceptedTermsAndConditions":true,"allowDirectSubmit":true,"archivedVersions":[],"articleType":"Research Article","associatedPublications":[],"authors":[{"id":285331498,"identity":"d38abdef-a100-4ce0-a3da-f01f7690dd14","order_by":0,"name":"Ramazan Birgul","email":"data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAZAAAAAyAQMAAABI0h/eAAAABlBMVEX///8AAABVwtN+AAAACXBIWXMAAA7EAAAOxAGVKw4bAAAA/klEQVRIiWNgGAWjYBCDBDYQ+aDiAJh34AHRWhLOHGDgAWlJIEYLmExsg2hhwKfFvP104scfNXfy+KSPX5NInHdHzl7s8EOgLXZyug3Ytcicyd0sIXHsWTEbX06ZROK2Z8Y80mkGQC3JxmYHsGuRYMjdIGHAdjixjYcnDajlcGKPdAJIy4HEbbi08L/d/CPhH0zLHJCW9A/4tUjkbpM42AbSwn5MIrEBpCWHgC0Sb7dZNvYdLmbj4WG2SDh22Jjndk7BgQQDPH7hz91888e3w3nyPewPb3yoOSzHPjt984cPFXZyuLQgAR4DJI4BTmXIgP0BUcpGwSgYBaNg5AEAt89kIJliFkMAAAAASUVORK5CYII=","orcid":"","institution":"Izmir Tepecik Eğitim ve Araştırma Hastanesi","correspondingAuthor":true,"prefix":"","firstName":"Ramazan","middleName":"","lastName":"Birgul","suffix":""},{"id":285331499,"identity":"fce17dd8-ac25-4623-adbd-5cd15913a910","order_by":1,"name":"Ahmet Kursad Sakallioglu","email":"","orcid":"","institution":"Trakya University","correspondingAuthor":false,"prefix":"","firstName":"Ahmet","middleName":"Kursad","lastName":"Sakallioglu","suffix":""}],"badges":[],"createdAt":"2024-03-23 21:59:17","currentVersionCode":1,"declarations":"","doi":"10.21203/rs.3.rs-4155863/v1","doiUrl":"https://doi.org/10.21203/rs.3.rs-4155863/v1","draftVersion":[],"editorialEvents":[],"editorialNote":"","failedWorkflow":false,"files":[{"id":54495200,"identity":"49c68a2d-bfae-4256-a618-e121c4e1431b","added_by":"auto","created_at":"2024-04-11 11:26:09","extension":"pdf","order_by":0,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":262495,"visible":true,"origin":"","legend":"","description":"","filename":"manuscript.pdf","url":"https://assets-eu.researchsquare.com/files/rs-4155863/v1/04ada643-4781-49a1-880d-08776cbec2e6.pdf"}],"financialInterests":"No competing interests reported.","formattedTitle":"Investigation of Anterior Segment and Pupillometry Changes with Sirius Corneal Topography in Chronic Smokers","fulltext":[{"header":"Introduction","content":"\u003cp\u003eChronic smoking is still one of the leading global health problems. It contains about 4000 different substances, which have many effects on the body, especially cancer and lung diseases (\u003cspan citationid=\"CR1\" class=\"CitationRef\"\u003e1\u003c/span\u003e). In ophthalmological practice, some studies have shown that chronic smoking causes retinal vein thrombosis, optic neuropathy, dry eye, Grave\u0026rsquo;s ophthalmopathy and macular degeneration (\u003cspan additionalcitationids=\"CR3\" citationid=\"CR2\" class=\"CitationRef\"\u003e2\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR4\" class=\"CitationRef\"\u003e4\u003c/span\u003e).\u003c/p\u003e \u003cp\u003eThe ocular effects of cigarette smoking occur in various ways. Thrombosis is caused by increasing platelet aggregation in the blood, increasing free oxygen radicals and the toxic effect of cigarette smoke directly on the ocular surface. Therefore, the eye, which is a mucosal surface, is one of the most vulnerable organs to cigarette smoke (\u003cspan citationid=\"CR5\" class=\"CitationRef\"\u003e5\u003c/span\u003e, \u003cspan citationid=\"CR6\" class=\"CitationRef\"\u003e6\u003c/span\u003e). Although some studies have reported that cigarette smoke causes dry eye and meibomian gland dysfunction, other studies claimed the opposite (\u003cspan additionalcitationids=\"CR8 CR9\" citationid=\"CR7\" class=\"CitationRef\"\u003e7\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR10\" class=\"CitationRef\"\u003e10\u003c/span\u003e). In addition, some studies have reported that cigarette smoke decreases CCT, while other have reported that it does not affect CCT (\u003cspan citationid=\"CR7\" class=\"CitationRef\"\u003e7\u003c/span\u003e, \u003cspan citationid=\"CR11\" class=\"CitationRef\"\u003e11\u003c/span\u003e).\u003c/p\u003e \u003cp\u003eThe most important reason for cigarette addiction is the nicotine content. Nicotine is converted into cotinine, its main component, in the blood, and this has systemic effects. Generally, cotinine affects the sympathetic system and increases heart rate and blood pressure. It affects the eye by changing the diameter of the pupil. While the expected effect of cotinine is dilation of the pupil diameter (\u003cspan citationid=\"CR12\" class=\"CitationRef\"\u003e12\u003c/span\u003e, \u003cspan citationid=\"CR13\" class=\"CitationRef\"\u003e13\u003c/span\u003e), some studies have reported that it narrows the pupil diameter (\u003cspan citationid=\"CR14\" class=\"CitationRef\"\u003e14\u003c/span\u003e, \u003cspan citationid=\"CR15\" class=\"CitationRef\"\u003e15\u003c/span\u003e).\u003c/p\u003e \u003cp\u003eThese contradictory results in chronic smokers indicate the need for a more comprehensive study. The aim of this study was to evaluate the anterior segment and pupillary changes in chronic smokers using Sirius corneal topography.\u003c/p\u003e"},{"header":"Materials and Methods","content":"\u003cp\u003e This prospective, cross-sectional study adhered to the principles of the Declaration of Helsinki. Informed consent was obtained from all participants. After obtaining local ethical approval, 70 right eyes of 70 chronic smokers and 72 right eyes of 72 healthy controls with no smoking history were included in the study.\u003c/p\u003e \u003cp\u003eSubjects who regularly smoked at least one packet of cigarettes per day for the last 5 years were included in the study group. The subjects in the control group had not smoked or been exposed to passive smoking throughout their lives. Exclusion criteria for both the chronic smoker group and the control group were spherical and cylindrical refractive error over 1 dioptre, contact lens use, use of any topical drops or any history of ocular surgery or disease.\u003c/p\u003e \u003cp\u003eLevels of cotinine, the main metabolite of nicotine in the blood, gradually increase during the day (\u003cspan citationid=\"CR16\" class=\"CitationRef\"\u003e16\u003c/span\u003e). Therefore, all participants were asked not to smoke for 24 hours. Best corrected visual acuity was measured in all subjects. Anterior segment and fundus examinations and a detailed ophthalmological examination were performed.\u003c/p\u003e \u003cp\u003eMeasurements were conducted with Sirius corneal topography (CSO, Firenze, Italy) by the same technician under the same lighting conditions. To eliminate the possible effects of environmental factors and diurnal variations, all measurements were taken at the same time of the day. All subjects underwent three consecutive measurements. CCT; CV; ACD; ACA; ACV; first NCTBUT; mean NCTBUT; meibography; scotopic, mesopic and photopic pupil sizes; and dynamic pupil sizes at 0, 1, 2, 4, 6, 8 and 10 s were measured.\u003c/p\u003e \u003cdiv id=\"Sec3\" class=\"Section2\"\u003e \u003ch2\u003eMeibography\u003c/h2\u003e \u003cp\u003eMeibography was performed with a Scheimpflug camera Placido topography device (Sirius, CSO, Firenze, Italy). Patients\u0026rsquo; upper and lower lids were everted with a cotton applicator. The imaging included all meibomian glands and was repeated three times by the same technician under the same illumination. The images were evaluated using the computer-aided Phoenix Meibography Imaging Module. However, the meibomian gland borders had to be drawn manually. The missing area score was calculated automatically with a predetermined degree. These values expressed the percentage of lost area as follows: (0) 0%, (\u003cspan citationid=\"CR1\" class=\"CitationRef\"\u003e1\u003c/span\u003e)\u0026thinsp;\u0026lt;\u0026thinsp;25%, (\u003cspan citationid=\"CR2\" class=\"CitationRef\"\u003e2\u003c/span\u003e) 25\u0026ndash;50%, (\u003cspan citationid=\"CR3\" class=\"CitationRef\"\u003e3\u003c/span\u003e) 51\u0026ndash;75% and (\u003cspan citationid=\"CR4\" class=\"CitationRef\"\u003e4\u003c/span\u003e)\u0026thinsp;\u0026gt;\u0026thinsp;75% (\u003cspan citationid=\"CR17\" class=\"CitationRef\"\u003e17\u003c/span\u003e).\u003c/p\u003e \u003c/div\u003e\n\u003ch3\u003ePupillometry\u003c/h3\u003e\n\u003cp\u003eSirius corneal topography (CSO, Firenze, Italy) Phoenix v2.1 software was used for pupillometry. For static pupillometry, scotopic pupil diameter was measured at 0.4 lux illumination after 5 m of dark adaptation. Afterwards, mesopic pupil diameter at 4 lux illumination and photopic pupil diameter at 40 lux illumination were measured. After static pupillometry, dynamic pupillometry was performed at 500 lux illumination at 0, 1, 2, 4, 6, 8 and 10 s.\u003c/p\u003e \u003cdiv id=\"Sec5\" class=\"Section2\"\u003e \u003ch2\u003eStatistical Analyses\u003c/h2\u003e \u003cp\u003eStatistical analyses were performed using IBM SPSS (IBM Corp., Armonk, NY, USA) version 20.0. Numerical descriptive statistics are presented as means and standard deviations for normally distributed variables. Descriptive statistics of categorical variables are presented as percentages. The Kolmogorov\u0026ndash;Smirnov test was used to assess the normality of the data. The independent samples t-test was used to compare two independent groups. The significance level was p\u0026thinsp;\u0026lt;\u0026thinsp;0.05.\u003c/p\u003e \u003c/div\u003e"},{"header":"Results","content":"\u003cp\u003eOf the 70 subjects in the chronic smoker group, 47 were male (67.1%), and 23 were female (32.9%). In the control group, subjects were male (63.9%), and 26 subjects were female (36.1%). The mean age of the study group was 44.7\u0026thinsp;\u0026plusmn;\u0026thinsp;9.6 years (range: 23\u0026ndash;67), while the mean age of the control group was 46.4\u0026thinsp;\u0026plusmn;\u0026thinsp;11.2 years (range: 19\u0026ndash;69). When both groups were compared in terms of gender and age, there were no statistically significant differences between them (Table\u0026nbsp;\u003cspan refid=\"Tab1\" class=\"InternalRef\"\u003e1\u003c/span\u003e).\u003c/p\u003e \u003cp\u003e \u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab1\" border=\"1\"\u003e \u003ccaption language=\"En\"\u003e \u003cdiv class=\"CaptionNumber\"\u003eTable 1\u003c/div\u003e \u003cdiv class=\"CaptionContent\"\u003e \u003cp\u003eRelationship of gender and age with smoking status\u003c/p\u003e \u003c/div\u003e \u003c/caption\u003e \u003ccolgroup cols=\"4\"\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c3\" colnum=\"3\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c4\" colnum=\"4\"\u003e\u003c/div\u003e \u003cthead\u003e \u003ctr\u003e \u003cth align=\"left\" colname=\"c1\"\u003e\u0026nbsp;\u003c/th\u003e \u003cth align=\"left\" colname=\"c2\"\u003e \u003cp\u003eChronic Smoker Group\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c3\"\u003e \u003cp\u003eControl Group\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c4\"\u003e \u003cp\u003eP\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003c/thead\u003e \u003ctbody\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cb\u003eMale\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e47 (67.1%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e46 (63.9%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\" morerows=\"1\" rowspan=\"2\"\u003e \u003cp\u003e0.726\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cb\u003eFemale\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e23 (32.9%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e26 (36.1%)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cb\u003eAge\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e44.7\u0026thinsp;\u0026plusmn;\u0026thinsp;9.6\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e46.4\u0026thinsp;\u0026plusmn;\u0026thinsp;11.2\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e0.342\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003c/tbody\u003e \u003c/colgroup\u003e \u003ctfoot\u003e \u003ctr\u003e\u003ctd colspan=\"4\"\u003e\u003cem\u003eKolmogorov\u0026ndash;Smirnov, Independent Sample Test *p\u0026thinsp;\u0026lt;\u0026thinsp;0.05\u003c/em\u003e\u003c/td\u003e\u003c/tr\u003e \u003c/tfoot\u003e \u003c/table\u003e\u003c/div\u003e \u003c/p\u003e \u003cp\u003eIn terms of anterior segment parameters, CCT was 538.6\u0026thinsp;\u0026plusmn;\u0026thinsp;29.4 \u0026micro; in the chronic smoker group and 542.9\u0026thinsp;\u0026plusmn;\u0026thinsp;29.5 \u0026micro; in the control group. When other anterior segment parameters were analysed, CV was 55.1\u0026thinsp;\u0026plusmn;\u0026thinsp;3.8 mm\u0026sup3; in the chronic smoker group and 55.8\u0026thinsp;\u0026plusmn;\u0026thinsp;3.4 mm\u0026sup3; in the control group, ACD was 2.8\u0026thinsp;\u0026plusmn;\u0026thinsp;0.3 mm in the chronic smoker group and 2.8\u0026thinsp;\u0026plusmn;\u0026thinsp;0.4 mm in the control group, ACA was 44.3\u0026thinsp;\u0026plusmn;\u0026thinsp;4.5\u0026deg; in the chronic smoker group and 43.7\u0026thinsp;\u0026plusmn;\u0026thinsp;6.1\u0026deg; in the control group and ACV was 159.5\u0026thinsp;\u0026plusmn;\u0026thinsp;32.1 mm\u0026sup3; in the chronic smoker group and 153.3\u0026thinsp;\u0026plusmn;\u0026thinsp;39.2 mm\u0026sup3; in the control group. No significant differences were found between the chronic smoker and control groups in terms of CCT, CV, ACD, ACA or ACV (Table\u0026nbsp;\u003cspan refid=\"Tab2\" class=\"InternalRef\"\u003e2\u003c/span\u003e).\u003c/p\u003e \u003cp\u003e \u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab2\" border=\"1\"\u003e \u003ccaption language=\"En\"\u003e \u003cdiv class=\"CaptionNumber\"\u003eTable 2\u003c/div\u003e \u003cdiv class=\"CaptionContent\"\u003e \u003cp\u003eRelationship of CCT, CV, ACD, ACA and ACV with smoking status\u003c/p\u003e \u003c/div\u003e \u003c/caption\u003e \u003ccolgroup cols=\"4\"\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c3\" colnum=\"3\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c4\" colnum=\"4\"\u003e\u003c/div\u003e \u003cthead\u003e \u003ctr\u003e \u003cth align=\"left\" colname=\"c1\"\u003e\u0026nbsp;\u003c/th\u003e \u003cth align=\"left\" colname=\"c2\"\u003e \u003cp\u003eChronic Smoker Group\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c3\"\u003e \u003cp\u003eControl Group\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c4\"\u003e \u003cp\u003eP\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003c/thead\u003e \u003ctbody\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cb\u003eCCT\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e538.6\u0026thinsp;\u0026plusmn;\u0026thinsp;29.4 \u0026micro;\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e542.9\u0026thinsp;\u0026plusmn;\u0026thinsp;29.5 \u0026micro;\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e0.385\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cb\u003eCV\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e55.1\u0026thinsp;\u0026plusmn;\u0026thinsp;3.8 mm\u0026sup3;\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e55.8\u0026thinsp;\u0026plusmn;\u0026thinsp;3.4 mm\u0026sup3;\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e0.240\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cb\u003eACD\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e2.8\u0026thinsp;\u0026plusmn;\u0026thinsp;0.3 mm\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e2.8\u0026thinsp;\u0026plusmn;\u0026thinsp;0.4 mm\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e0.285\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cb\u003eACA\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e44.3\u0026thinsp;\u0026plusmn;\u0026thinsp;4.5\u0026deg;\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e43.7\u0026thinsp;\u0026plusmn;\u0026thinsp;6.1\u0026deg;\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e0.496\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cb\u003eACV\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e159.5\u0026thinsp;\u0026plusmn;\u0026thinsp;32.1 mm\u0026sup3;\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e153.3\u0026thinsp;\u0026plusmn;\u0026thinsp;39.2 mm\u0026sup3;\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e0.302\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003c/tbody\u003e \u003c/colgroup\u003e \u003ctfoot\u003e \u003ctr\u003e\u003ctd colspan=\"4\"\u003e\u003cem\u003eKolmogorov\u0026ndash;Smirnov, Independent Sample Test *p\u0026thinsp;\u0026lt;\u0026thinsp;0.05\u003c/em\u003e\u003c/td\u003e\u003c/tr\u003e \u003c/tfoot\u003e \u003c/table\u003e\u003c/div\u003e \u003c/p\u003e \u003cp\u003eWhen ocular surface parameters were analysed, first NCTBUT was 13.3\u0026thinsp;\u0026plusmn;\u0026thinsp;5.0 s in the chronic smoker group and 13.9\u0026thinsp;\u0026plusmn;\u0026thinsp;4.3 s in the control group, mean NCTBUT was 13.6\u0026thinsp;\u0026plusmn;\u0026thinsp;4.7 s in the chronic smoker group and 14.4\u0026thinsp;\u0026plusmn;\u0026thinsp;3.7 s in the control group and meibography was 7.9\u0026thinsp;\u0026plusmn;\u0026thinsp;5.2% in the chronic smoker group and 1.2\u0026thinsp;\u0026plusmn;\u0026thinsp;1.3% in the control group. When the groups were compared, there were no significant difference between them in terms of first NCTBUT and mean NCTBUT, but there was a significant difference in terms of meibography (Table\u0026nbsp;\u003cspan refid=\"Tab3\" class=\"InternalRef\"\u003e3\u003c/span\u003e).\u003c/p\u003e \u003cp\u003e \u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab3\" border=\"1\"\u003e \u003ccaption language=\"En\"\u003e \u003cdiv class=\"CaptionNumber\"\u003eTable 3\u003c/div\u003e \u003cdiv class=\"CaptionContent\"\u003e \u003cp\u003eRelationship of first NCTBUT, mean NCTBUT and meibography with smoking status\u003c/p\u003e \u003c/div\u003e \u003c/caption\u003e \u003ccolgroup cols=\"4\"\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c3\" colnum=\"3\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c4\" colnum=\"4\"\u003e\u003c/div\u003e \u003cthead\u003e \u003ctr\u003e \u003cth align=\"left\" colname=\"c1\"\u003e\u0026nbsp;\u003c/th\u003e \u003cth align=\"left\" colname=\"c2\"\u003e \u003cp\u003eChronic Smoker Group\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c3\"\u003e \u003cp\u003eControl Group\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c4\"\u003e \u003cp\u003eP\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003c/thead\u003e \u003ctbody\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cb\u003eFirst NCTBUT\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e13.3\u0026thinsp;\u0026plusmn;\u0026thinsp;5.0 s\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e13.9\u0026thinsp;\u0026plusmn;\u0026thinsp;4.3 s\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e0.389\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cb\u003eMean NCTBUT\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e13.6\u0026thinsp;\u0026plusmn;\u0026thinsp;4.7 s\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e14.4\u0026thinsp;\u0026plusmn;\u0026thinsp;3.7 s\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e0.269\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cb\u003eMeibography\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e7.9\u0026thinsp;\u0026plusmn;\u0026thinsp;5.2%\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e1.2\u0026thinsp;\u0026plusmn;\u0026thinsp;1.3%\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e\u003cb\u003e0.000\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003c/tbody\u003e \u003c/colgroup\u003e \u003ctfoot\u003e \u003ctr\u003e\u003ctd colspan=\"4\"\u003e\u003cem\u003eKolmogorov\u0026ndash;Smirnov, Independent Sample Test *p\u0026thinsp;\u0026lt;\u0026thinsp;0.05\u003c/em\u003e\u003c/td\u003e\u003c/tr\u003e \u003c/tfoot\u003e \u003c/table\u003e\u003c/div\u003e \u003c/p\u003e \u003cp\u003eWhen the groups were analysed in terms of static pupillometry, the pupil size was 5.5\u0026thinsp;\u0026plusmn;\u0026thinsp;1.0 mm in the chronic smoker group and 5.1\u0026thinsp;\u0026plusmn;\u0026thinsp;0.8 mm in the control group under scotopic conditions, 5.5\u0026thinsp;\u0026plusmn;\u0026thinsp;1.0 mm in the chronic smoker group and 5.0\u0026thinsp;\u0026plusmn;\u0026thinsp;0.9 mm in the control group under mesopic conditions and 4.8\u0026thinsp;\u0026plusmn;\u0026thinsp;1.0 mm in the chronic smoker group and 4.2\u0026thinsp;\u0026plusmn;\u0026thinsp;0.9 mm in the control group under photopic conditions. There were statistically significant differences in the scotopic, mesopic and photopic pupil sizes between the groups.\u003c/p\u003e \u003cp\u003eDynamic pupillometry was 3.1\u0026thinsp;\u0026plusmn;\u0026thinsp;0.5 mm in the chronic smoker group and 2.8\u0026thinsp;\u0026plusmn;\u0026thinsp;0.5 mm in the control group at 0 s, 3.8\u0026thinsp;\u0026plusmn;\u0026thinsp;0.6 mm in the chronic smoker group and 3.6\u0026thinsp;\u0026plusmn;\u0026thinsp;0.6 mm in the control group at 1 s, 4.3\u0026thinsp;\u0026plusmn;\u0026thinsp;0.7 mm in the chronic smoker group and 4.0\u0026thinsp;\u0026plusmn;\u0026thinsp;0.6 mm in the control group at 2 s, 4.7\u0026thinsp;\u0026plusmn;\u0026thinsp;0.8 mm in the chronic smoker group and 4.5\u0026thinsp;\u0026plusmn;\u0026thinsp;0.7 mm in the control group at 4 s, 5.0\u0026thinsp;\u0026plusmn;\u0026thinsp;0.8 mm in the chronic smoker group and 4.8\u0026thinsp;\u0026plusmn;\u0026thinsp;0.8 mm in the control group at 6 s, 5.2\u0026thinsp;\u0026plusmn;\u0026thinsp;0.8 mm in the chronic smoker group and 5.0\u0026thinsp;\u0026plusmn;\u0026thinsp;0.8 mm in the control group at 8 s and 5.3\u0026thinsp;\u0026plusmn;\u0026thinsp;0.9 mm in the chronic smoker group and 5.1\u0026thinsp;\u0026plusmn;\u0026thinsp;0.9 mm in the control group at 10 s. When the groups were compared, significant differences were found for dynamic pupillometry at 0 and 1 s but not at 2, 4, 6, 8 or 10 s (Table\u0026nbsp;\u003cspan refid=\"Tab4\" class=\"InternalRef\"\u003e4\u003c/span\u003e).\u003c/p\u003e \u003cp\u003e \u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab4\" border=\"1\"\u003e \u003ccaption language=\"En\"\u003e \u003cdiv class=\"CaptionNumber\"\u003eTable 4\u003c/div\u003e \u003cdiv class=\"CaptionContent\"\u003e \u003cp\u003eRelationship of scotopic, mesopic and photopic as well as dynamic pupillometry pupil sizes at 0, 1, 2, 4, 6, 8 and 10 s with smoking status\u003c/p\u003e \u003c/div\u003e \u003c/caption\u003e \u003ccolgroup cols=\"4\"\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c3\" colnum=\"3\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c4\" colnum=\"4\"\u003e\u003c/div\u003e \u003cthead\u003e \u003ctr\u003e \u003cth align=\"left\" colname=\"c1\"\u003e\u0026nbsp;\u003c/th\u003e \u003cth align=\"left\" colname=\"c2\"\u003e \u003cp\u003eChronic Smoker Group\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c3\"\u003e \u003cp\u003eControl Group\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c4\"\u003e \u003cp\u003eP\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003c/thead\u003e \u003ctbody\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cb\u003eScotopic\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e5.5\u0026thinsp;\u0026plusmn;\u0026thinsp;1.0 mm\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e5.1\u0026thinsp;\u0026plusmn;\u0026thinsp;0.8 mm\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e\u003cb\u003e0.004\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cb\u003eMesopic\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e5.5\u0026thinsp;\u0026plusmn;\u0026thinsp;1.0 mm\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e5.0\u0026thinsp;\u0026plusmn;\u0026thinsp;0.9 mm\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e\u003cb\u003e0.001\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cb\u003ePhotopic\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e4.8\u0026thinsp;\u0026plusmn;\u0026thinsp;1.0 mm\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e4.2\u0026thinsp;\u0026plusmn;\u0026thinsp;0.9 mm\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e\u003cb\u003e0.000\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cb\u003eDynamic 0 s\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e3.1\u0026thinsp;\u0026plusmn;\u0026thinsp;0.5 mm\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e2.8\u0026thinsp;\u0026plusmn;\u0026thinsp;0.5 mm\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e\u003cb\u003e0.007\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cb\u003eDynamic 1 s\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e3.8\u0026thinsp;\u0026plusmn;\u0026thinsp;0.6 mm\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e3.6\u0026thinsp;\u0026plusmn;\u0026thinsp;0.6 mm\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e\u003cb\u003e0.007\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cb\u003eDynamic 2 s\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e4.3\u0026thinsp;\u0026plusmn;\u0026thinsp;0.7 mm\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e4.0\u0026thinsp;\u0026plusmn;\u0026thinsp;0.6 mm\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e0.056\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cb\u003eDynamic 4 s\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e4.7\u0026thinsp;\u0026plusmn;\u0026thinsp;0.8 mm\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e4.5\u0026thinsp;\u0026plusmn;\u0026thinsp;0.7 mm\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e0.074\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cb\u003eDynamic 6 s\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e5.0\u0026thinsp;\u0026plusmn;\u0026thinsp;0.8 mm\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e4.8\u0026thinsp;\u0026plusmn;\u0026thinsp;0.8 mm\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e0.150\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cb\u003eDynamic 8 s\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e5.2\u0026thinsp;\u0026plusmn;\u0026thinsp;0.8 mm\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e5.0\u0026thinsp;\u0026plusmn;\u0026thinsp;0.8 mm\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e0.121\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cb\u003eDynamic 10 s\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e5.3\u0026thinsp;\u0026plusmn;\u0026thinsp;0.9 mm\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e5.1\u0026thinsp;\u0026plusmn;\u0026thinsp;0.9 mm\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e0.176\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003c/tbody\u003e \u003c/colgroup\u003e \u003ctfoot\u003e \u003ctr\u003e\u003ctd colspan=\"4\"\u003e\u003cem\u003eKolmogorov\u0026ndash;Smirnov, Independent Sample Test *p\u0026thinsp;\u0026lt;\u0026thinsp;0.05\u003c/em\u003e\u003c/td\u003e\u003c/tr\u003e \u003c/tfoot\u003e \u003c/table\u003e\u003c/div\u003e \u003c/p\u003e"},{"header":"Discussion","content":"\u003cp\u003eWe compared the chronic smoker group with the control group with the help of the results we obtained in this study. There were no statistically significant differences between the groups in terms of age; gender; CCT; CV; ACD; ACA; ACV; first NCTBUT; mean NCTBUT; or dynamic pupillometry at 2, 4, 6, 8 or 10 s. There were statistically significant differences between meibography; scotopic, mesopic and photopic static pupillometry; and dynamic pupillometry at 0 and 1 s.\u003c/p\u003e \u003cp\u003eSmoking has various systemic and ocular effects. It mainly causes lipid peroxidation in the vascular wall and platelet adhesion and aggregation. This results in atherosclerosis. It also increases proinflammatory cytokines such as calcitonin decreases anti-inflammatory cytokines such as ascorbic acid. All these systemic effects also affect ocular structures (5,8,18). Anterior segment structures such as the cornea, which is avascular, are especially affected by hypoxia and ischaemic conditions (\u003cspan citationid=\"CR19\" class=\"CitationRef\"\u003e19\u003c/span\u003e). In addition, it is known that free oxygen radicals are produced by the direct toxic effect of cigarette smoke and that smoking changes the structure of proteins in ocular structures (20). Knuutinen et al. (\u003cspan citationid=\"CR21\" class=\"CitationRef\"\u003e21\u003c/span\u003e) found that smoking decreased CCT by affecting collagen among these proteins. However, Ilhan et al. (\u003cspan citationid=\"CR22\" class=\"CitationRef\"\u003e22\u003c/span\u003e) reported that CCT did not change in their study. In our study, it was observed that CCT was not significantly different between the groups.\u003c/p\u003e \u003cp\u003eNo study in the literature has been conducted on the status of anterior segment elements other than CCT, CV, ACD, ACA and ACV in smokers. In our study, no significant differences were observed between the groups in terms of CV, ACD, ACA or ACV. This shows that although some studies have shown that smoking changes the proteins in ocular structures at the histological level, this does not significantly change the corneal and anterior segment structures anatomically.\u003c/p\u003e \u003cp\u003eThe mucosal surface of the body most exposed to cigarette smoke is the ocular surface (\u003cspan citationid=\"CR23\" class=\"CitationRef\"\u003e23\u003c/span\u003e). Since this surface is in direct contact with cigarette smoke, the tears and meibomian gland are affected. Cigarette smoke shows its effects by peroxidation on the lipid layer in tears and by increasing anti-inflammatory cytokines and hyperkeratinisation of the meibomian glands (\u003cspan citationid=\"CR10\" class=\"CitationRef\"\u003e10\u003c/span\u003e). In the studies in which tear parameters were analysed in the literature, quite contradictory results have been found in terms of the Schirmer and BUT tests. While some studies stated that parameters such as Schirmer and BUT decreased, others found that these parameters were not affected by smoking (\u003cspan additionalcitationids=\"CR7\" citationid=\"CR6\" class=\"CitationRef\"\u003e6\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR8\" class=\"CitationRef\"\u003e8\u003c/span\u003e, \u003cspan citationid=\"CR24\" class=\"CitationRef\"\u003e24\u003c/span\u003e). Since these studies were generally performed with the traditional BUT test, the non-contact method was used in our study, making the result more objective. In our study, there were no significant differences for the first and mean NCTBUTs between the groups. However, meibography results were significantly impaired in smokers compared to the control group. Smoking has been shown to cause meibomian gland dysfunction in other studies (\u003cspan citationid=\"CR10\" class=\"CitationRef\"\u003e10\u003c/span\u003e, \u003cspan citationid=\"CR25\" class=\"CitationRef\"\u003e25\u003c/span\u003e). This shows that although smoking causes meibomian gland dysfunction, lipid peroxidation on the tear layer is not as high as thought, and dysfunction of the meibomian glands does not affect tear quality.\u003c/p\u003e \u003cp\u003eThe effect of smoking on the pupil is mainly caused by nicotine. In the blood, nicotine turns into cotinine, its active metabolite, by binding to acetylcholine receptors (\u003cspan citationid=\"CR16\" class=\"CitationRef\"\u003e16\u003c/span\u003e, \u003cspan citationid=\"CR26\" class=\"CitationRef\"\u003e26\u003c/span\u003e). Since there are approximately 4000 chemical substances in cigarettes, Fernandes et al. (\u003cspan citationid=\"CR14\" class=\"CitationRef\"\u003e14\u003c/span\u003e) investigated cigarette substances other than nicotine to determine their effects on the pupil and found that no substance other than nicotine affected the pupil (\u003cspan citationid=\"CR14\" class=\"CitationRef\"\u003e14\u003c/span\u003e). Narrowing and dilation of the pupil occurs by the autonomic nervous system with the help of the sympathetic and parasympathetic systems. While the pupil dilates with the help of the sympathetic system and dilator muscles, it narrows with the help of the parasympathetic system and constrictor muscles. Nicotine affects the whole body by activating the sympathetic system, especially by increasing blood pressure by vasoconstriction, but its effects on the pupil are variable. The expected effect is in the direction of pupil dilation due to the sympathetic effect (\u003cspan citationid=\"CR13\" class=\"CitationRef\"\u003e13\u003c/span\u003e). While pupil dilation has been reported in some studies, pupil narrowing has been reported in other studies (\u003cspan citationid=\"CR13\" class=\"CitationRef\"\u003e13\u003c/span\u003e, \u003cspan citationid=\"CR15\" class=\"CitationRef\"\u003e15\u003c/span\u003e, \u003cspan citationid=\"CR23\" class=\"CitationRef\"\u003e23\u003c/span\u003e, \u003cspan citationid=\"CR27\" class=\"CitationRef\"\u003e27\u003c/span\u003e).\u003c/p\u003e \u003cp\u003eThis contradictory situation may be due to the effects of acute versus chronic smoking. Sobacı et al. (\u003cspan citationid=\"CR28\" class=\"CitationRef\"\u003e28\u003c/span\u003e) reported that nicotine narrowed the pupil in acute period and dilated the pupil in the chronic period. K\u0026ouml;ktekir et al. (\u003cspan citationid=\"CR15\" class=\"CitationRef\"\u003e15\u003c/span\u003e) found that the mesopic pupil size was smaller in smokers in their study. However, since they performed this measurement 2 hours after smoking, they attributed this finding to the acute effect of smoking. All these pupillary responses may be the result of nicotine-induced autonomic neuropathy (\u003cspan citationid=\"CR28\" class=\"CitationRef\"\u003e28\u003c/span\u003e, \u003cspan citationid=\"CR29\" class=\"CitationRef\"\u003e29\u003c/span\u003e). In our study, the pupil was evaluated in detail, and all functions were analysed by static and dynamic pupillometry. In the chronic period, we found that the pupil dilated at 0 and 1 s of scotopic, mesopic, photopic and dynamic pupillometry. This result is similar to Sobacı et al.\u0026rsquo;s (\u003cspan citationid=\"CR28\" class=\"CitationRef\"\u003e28\u003c/span\u003e) finding that the pupil dilates in the chronic period. In the following dynamic 2, 4, 6, 8 and 10 s, pupil sizes were found to be larger in chronic smokers, but these differences were not statistically significant.\u003c/p\u003e \u003cp\u003eThis study had some limitations. Firstly, in the chronic smoker group, the duration of smoking and the number of packs smoked per day were questioned, which did not help us to examine whether there was a significant difference between chronic smokers in terms of duration and amount of smoking. Secondly, the nicotine level in the blood of the subjects at the time of measurement was not analysed. Future studies could investigate whether this has any effect on the results.\u003c/p\u003e"},{"header":"Conclusion","content":"\u003cp\u003eAs smoking has effects on the whole body, it also has ocular effects. Since the anterior segment, unlike other ocular structures, is exposed to the direct toxic effects of cigarette smoke, it is the most affected part of the eye. In this study, only the meibomian gland was affected among the anterior segment structures. Although the meibomian gland plays a role in the production of tears, the direct toxic and systemic effects of smoking did not affect tear quality. The effects on the pupil were analysed for chronic smokers. Static pupillometry and dynamic pupillometry showed a significant increase in pupil diameter in the early periods and a non-significant increase in the later periods, indicating the development of nicotinic autonomic neuropathy on the pupil.\u003c/p\u003e"},{"header":"Declarations","content":"\u003ch2\u003eAuthor Contribution\u003c/h2\u003e\u003cp\u003eR.B. wrote the main manuscript text and AKS prepared tables. All authors reviewed the manuscript\u003c/p\u003e"},{"header":"References","content":"\u003col\u003e\u003cli\u003e\u003cspan\u003eVan der Vaart H, Postma DS, et al. Acute effects of cigarette smoke on inflammation and oxidative stress a review. Thorax 2004;59:713\u0026ndash;721.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eThe Eye Disease Case-Control Study Group. Risk factors for neovascular age-related macular degeneration. Arch Ophthalmol 1992;110:1701\u0026ndash;1708.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003ePrummel MF, Wiersinga WM. Smoking and risk of Graves\u0026rsquo; disease. J Am Med Assoc 1993;269:479\u0026ndash;482.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eChia EM, Mitchell P, Rochtchina E, et al. Prevalence and associations of dry eye syndrome in an older population: the Blue Mountains Eye Study. Clin Exp Ophthalmol 2003;31:229\u0026ndash;232.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eLind L, Sarabi M, Millgard J. The effect of smoking on endothelial vasodilatory function evaluated by local infusion of metacholine in the forearm is dependent on the duration of smoking. Nicotine Tob Res 2003;5(1):125\u0026ndash;130.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eTariq MA, et al. Association of dry eye disease with smoking: a systematic review and metaanalysis. Indian J Ophthalmol 2022;70(6):1892\u0026ndash;1904.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eSayin N, Kara N, Pekel G, Altinkaynak H. Effects of chronic smoking on central corneal thickness, endothelial cell, and dry eye parameters. Cutan Ocul Toxicol 2014;33(3):201\u0026ndash;205.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eNarnoli P, Dhasmana R, Khanduri R. Dry eye disease and retinal nerve fiber layer changes in chronic smokers. Indian J Ophthalmol 2021;69(5):1178\u0026ndash;1182.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eGabela Merino M, Gonzalez Garcia MJ, et al. Dry eye signs and symptoms in hydrogel contact lens wearers: relation to smoking habit. Arch Soc Esp Oftalmol 2003;78:543\u0026ndash;548.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eWang S, et al. Impact of chronic smoking on meibomian gland dysfunction. PLoS One 2016;11(12):e0168763.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eKnuutinen A, Kokkonen N, Risteli J, et al. Smoking affects collagen synthesis and extracellular matrix turnover in human skin. Br J Dermatol 2002;146:588\u0026ndash;594.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eBardak H, et al. Evaluation of the acute changes in objective accommodation, pupil size and ocular wavefront aberrations after cigarette smoking. Cutan Ocul Toxicol 2017;36(1):25\u0026ndash;28.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eErdem U, et al. Acute effect of cigarette smoking on pupil size and ocular aberrations: a pre- and postsmoking study. J Ophthalmol 2015;2015:625470.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eFernandes TP, et al. Effects of nicotine gum administration on vision (ENIGMA-Vis): study protocol of a double-blind, randomized, and controlled clinical trial. Front Hum Neurosci 2020;14:314.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eK\u0026ouml;ktekir BE, at al. The effects of smoking on anterior segment parameters, retinal nerve fiber layer, and pupillary functions. Turk J Ophthalmol 2014;44:11\u0026ndash;14.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eBenowitz, NL. Cotinine as a biomarker of environmental tobacco smoke exposure. Epidemiologic Reviews 1996;18(2):188\u0026ndash;204.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003ePult H, Riede-Pult B. Comparison of subjective grading and objective assessment in meibography. Cont Lens Anterior Eye 2013;36:22\u0026ndash;27.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eFernandez-Robredo P, Moya D, Rodriguez JA, Garcia-Layana A. Vitamins C and E reduce retinal oxidative stress and nitric oxide metabolites and prevent ultrastructural alterations in porcine hypercholesterolemia. Invest Ophthalmol Vis Sci 2005;46:1140\u0026ndash;1146.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eTimothy CO, Nneli RO. The effects of cigarette smoking on intraocular pressure and arterial blood pressure of normotensive young Nigerian male adults. Niger J Physiol Sci 2007;22:33\u0026ndash;36.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eMantelli F, Giordano MM, Macchi I, Lambiase A, Bonini S. The cellular mechanisms of dry eye: pathogenisis to treatment. J Cell Physiol 2013;228:2253\u0026ndash;2256.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eKnuutinen A, Kokkonen N, Risteli J, et al. Smoking affects collagen synthesis and extracellular matrix turnover in human skin. Br J Dermatol 2002;146:588\u0026ndash;594.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eIlhan N, et al. Effects of smoking on central corneal thickness and the corneal endothelial cell layer in otherwise healthy subjects. Eye Contact Lens 2016;42(5):303\u0026ndash;307.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eLatif N, Naroo SA. Transient effects of smoking on the eye. Cont Lens Anterior Eye 2022;45(5):101595.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eGabela Merino M, Gonzalez Garcia MJ, et al. Dry eye signs and symptoms in hydrogel contact lens wearers: relation to smoking habit. Arch Soc Esp Oftalmol 2003;78:543\u0026ndash;548.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eAğın A, Kocabeyoğlu S, \u0026Ccedil;olak D, İrke\u0026ccedil; M. Ocular surface, meibomian gland alterations, and in vivo confocal microscopy characteristics of corneas in chronic cigarette smokers. Graefes Arch Clin Exp Ophthalmol 2020;258(4):835\u0026ndash;841.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eDani JA. Neuronal nicotinic acetylcholine receptor structure and function and response to nicotine. Int Rev Neurobiol 2015;124:3\u0026ndash;19. doi:\u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003e10.1016/bs.irn.2015\u003c/span\u003e\u003cspan address=\"10.1016/bs.irn.2015\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eLie TC, Domino EF. Effects of tobacco smoking on the human pupil. Int J Clin Pharmacol Ther. 1999;37(4):184\u0026ndash;188.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eSobacı G, Erdem U, Gundoğan F\u0026Ccedil;, Musayev S. The effect of chronic smoking on the pupil and photostress recovery time. Ophthalmic Res 2013;49(3):167\u0026ndash;170.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eBremmer FD, Smith SE. Pupil abnormalities in selected autonomic neuropathies. J Neuroophthalmol 2006;26:209\u0026ndash;219.\u003c/span\u003e\u003c/li\u003e\u003c/ol\u003e"}],"fulltextSource":"","fullText":"","funders":[],"hasAdminPriorityOnWorkflow":false,"hasManuscriptDocX":true,"hasOptedInToPreprint":true,"hasPassedJournalQc":"","hasAnyPriority":false,"hideJournal":true,"highlight":"","institution":"","isAcceptedByJournal":false,"isAuthorSuppliedPdf":false,"isDeskRejected":"","isHiddenFromSearch":false,"isInQc":false,"isInWorkflow":false,"isPdf":false,"isPdfUpToDate":true,"isWithdrawnOrRetracted":false,"journal":{"display":true,"email":"[email protected]","identity":"researchsquare","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":true,"externalIdentity":"","sideBox":"","snPcode":"","submissionUrl":"/submission","title":"Research Square","twitterHandle":"researchsquare","acdcEnabled":true,"dfaEnabled":false,"editorialSystem":"","reportingPortfolio":"","inReviewEnabled":false,"inReviewRevisionsEnabled":true},"keywords":"","lastPublishedDoi":"10.21203/rs.3.rs-4155863/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-4155863/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003cp\u003e\u003cstrong\u003ePurpose\u003c/strong\u003e Chronic smoking is still one of the world’s leading health problems. In addition to the systemic effects of cigarette smoking, ocular effects are also present, as ocular structures are a mucosal surface. The aim of this study was to investigate the effects of chronic cigarette smoking on the anterior segment and pupil using Sirius corneal topography.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eMaterials and Methods\u003c/strong\u003e The study included 70 chronic smokers in the experimental group and 72 non-smokers in the control group. Central corneal thickness (CCT); corneal volume (CV); anterior chamber depth (ACD); anterior chamber angle (ACA); anterior chamber volume (ACV); first non-contact tear breakup time (NCTBUT); mean NCTBUT; meibography; scotopic, mesopic and photopic pupil sizes; and dynamic pupil sizes at 0, 1, 2, 4, 6, 8 and 10 s were measured.\u0026nbsp;\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eResults \u003c/strong\u003eThere were no statistically significant differences between the chronic smoker group and the control group in terms of age; gender; CCT; CV; ACD; ACA; ACV; first NCTBUT; mean NCTBUT; or dynamic pupillometry at 2, 4, 6, 8 and 10 s. There were statistically significant differences between the groups in terms of meibography; scotopic, mesopic and photopic static pupillometry; and dynamic pupillometry at 0 and 1 s.\u0026nbsp;\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eConclusion\u003c/strong\u003e In this study, only the meibomian gland was affected among the anterior segment structures. Changes in other anterior segment structures were not significant. On the pupil, chronic smoking increased the scotopic, mesopic and photopic pupil diameter and the early stages of dynamic pupillometry. This indicates that cigarette smoking results in nicotinic autonomic neuropathy on the pupil.\u003c/p\u003e","manuscriptTitle":"Investigation of Anterior Segment and Pupillometry Changes with Sirius Corneal Topography in Chronic Smokers","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2024-04-01 09:24:39","doi":"10.21203/rs.3.rs-4155863/v1","editorialEvents":[{"type":"communityComments","content":0}],"status":"published","journal":{"display":true,"email":"[email protected]","identity":"researchsquare","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":true,"externalIdentity":"","sideBox":"","snPcode":"","submissionUrl":"/submission","title":"Research Square","twitterHandle":"researchsquare","acdcEnabled":true,"dfaEnabled":false,"editorialSystem":"","reportingPortfolio":"","inReviewEnabled":false,"inReviewRevisionsEnabled":true}}],"origin":"","ownerIdentity":"2fa0e822-4590-428e-91d2-29898b01e8c0","owner":[],"postedDate":"April 1st, 2024","published":true,"recentEditorialEvents":[],"rejectedJournal":[],"revision":"","amendment":"","status":"posted","subjectAreas":[],"tags":[],"updatedAt":"2025-02-21T05:38:30+00:00","versionOfRecord":[],"versionCreatedAt":"2024-04-01 09:24:39","video":"","vorDoi":"","vorDoiUrl":"","workflowStages":[]},"version":"v1","identity":"rs-4155863","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-4155863","identity":"rs-4155863","version":["v1"]},"buildId":"qtupq5eGEP_6zYnWcrvyt","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}