Stem cells for ocular therapies

The ability to rehabilitate and restore visual function is the ultimate aspiration of the science of ophthalmology. Conventional ocular treatment strategies have focused on protecting against vision impairment with the administration of laser treatments or drugs or by surgical intervention. The current standard medical treatment modalities for the most frequent causes of blindness are very effective. However, ophthalmology has yet been unable to discover a cure for many common ocular dystrophies or a comprehensive strategy to halt the progression of blindness. It is therefore necessary to continue to formulate new treatment strategies to cure the causes of blindness and to achieve the best standard of visual acuity. To these ends, stem cells have immense potential to replenish the degenerated cells in our body, including damaged cells in the eye. The mammalian eye, with its intricate structure and unique characteristics, offers various advantages for stem-cell-based therapies, including its immunologically privileged status and easy accessibility for therapeutic intervention. Already, several stem-cell-based preclinical and clinical trials are in progress, investigating treatments for a wide range of ocular diseases in various animal models, as well as in humans. Stem cells, including pluripotent stem cells (both embryonic stem cells and induced pluripotent stem cells) and adult stem cells, have already been successfully manipulated to generate specialized ocular cells and tissues. Several laboratories have reported the generation of cornea-specific cells, such as corneal epithelial and endothelial cells, retina-specific cells such as retinal pigment epithelial cells, photoreceptors, and retinal ganglion cells, lens, conjunctival, limbal, and trabecular-meshwork-specific cells. In conclusion, although various concerns still need to be addressed, the use of bioengineered stem cells appears to be a promising therapeutic strategy for future replacement and regeneration of ocular tissues in cases of formerly incurable ocular diseases.