Perceiving Retinal Progress: From Anatomy to Bioengineering Organoids

The retina, a crucial part of the eye, is made up of various cells and structures that are essential for the conversion of a light stimulus into an electric signal for the brain to develop an image. The different cells of the retina including the retinal pigment epithelium, rods and cones, and the retinal ganglion cells together are involved in the transduction of light and the formation of connections with the optic nerve. This is a complex and efficient system with distinct layers of cells being involved in the absorbing of unnecessary light stimulus and providing physiological support. Retinal disorders are most prevalent in people above the age of 50 and cases of blindness are in the millions, making the need for better treatment options a pressing matter. Shortage of donors and patient incompatibility are reasons for which the focus has moved to the use of stem cells and tissue engineering as an alternative treatment option. Induced pluripotent stem cells can be engineered to differentiate into retinal cells using supplements like SMAD antagonists and retinoic acid. Inactivating motor proteins and using Wnt/BMP4 antagonists facilitate the development of retinal neural characteristics to give three-dimensional retinal organoids. Microfluidics provides vascularization for better nutrient supply to make improved functional tissue models. Retinal organoids are hence promising for drug discovery and development, disease modeling, transplant alternatives, and developmental biology.