My delve into opthalmology resulted as I lay on the couch watching one of my favourite shows, Call for Help. During one of the intermissions, "Medical Minutes" popped up where they featured a patient who lost his eyesight when he was 3 due to some chemical accident. His eyesight was partially restored by stem cell transplantation. I jumped up and started doing some research on the internet.

The technique is limbal stem cell transplant. The limbus is the area where your cornea meets with the sclera (the white part of your eye). It is in this area that stem cells reside and eventually grow into mature corneal cells. In many corneal conditions, these stem cells are destroyed thus distorting the anatomy and physiology of the cornea resulting in a hazy cornea and the resulting blindness. Among such conditions are ocular surface malignancy, chemical burns and ocular surface destruction eg by autoimmune conditions (SJS and ocular cicatricial pemphigoid).

By replacing these limbal stem cells, the surface of the cornea will eventually be repopulated by normal corneal cells. This improves vision. Unlike corneal transplant, homologous limbal stem cell transplant require life long immunosuppression with cyclosporin. However, if the other eye is intact, an autologous transplant can be performed negating the need for immunosuppressive therapy. Corneal transplant can also be performed after a limbal transplant but initial studies show that it is inferior to limbal transplant alone.

Limbal stem cell transplant has also been shown superior as compared to conventional treatment for recurrent pterygium. The recurrence rate is much lower (2.9% vs 19.4%) in favour of limbal stem cell transplant.

EyeNet
HealthLink : The University Hospital
Medscape (The Cornea : New Biologic Research)