Tuesday, December 7, 2010

Sight Recovery and it's Discontents

Many of us take for granted that we have the ability to see the world around us. Vision is an invaluable sense that leads us to make dozens of behavioural decisions every second. Historically, the fate of individuals blinded since childhood due to accident or congenital diseases were destined to never see again.

Although these procedures are rare, there are methods which can restore their sight. For example, corneal graft transplantation involves removing the cornea from a deceased donor and surgically placing it onto the eye of a blind patient after removing the unusable cornea. Another technique is corneal stem cell transplantation. Limbal stem cells (immature epithelial cells) from healthy corneas are removed and cultured into a new cornea in ex vivo. And now, new research in the field of bioenegineering is investigating the use of synthetic corneas made from complex polymers.
The ability to give someone their sight back is extraordinary. However, regaining vision after decades of blindness may not always be a happy or easy experience. There are two sight recovery cases which demonstrate the powerful effects of vision restoration.

Patient SB has become a famous case study in vision research. He was blind from age 10 months due to complications with a smallpox vaccination. At the age of 52, he received a corneal graft operation to restore his sight. SB thought that vision would be positive and life-altering. However, when his surgical recovery was complete and the bandages came off, he was ultimately "disappointed in what he saw." SB went from being a successful blind person to an unsuccessful sighted individual. Although it is hard to understand if you have not experienced it, vision can be a shocking and confusing blur (no pun intended!).

If you are not accustomed to that level of mental stimulation, the variety of information as well as the sheer quantity of input we get from sight is very overwhelming. Your brain needs to essentially learn to see. Therefore, patients like SB need to be given the proper psychosocial support in order to function and mentally adjust to their drastically different lives. Unfortunately for SB, he did not receive adequate support to help him through this transformation. Within two years of regaining his sight, SB became clinically depressed and died after catching a brief illness. SB was simply not ready to handle his new sensory modality.

This story, greatly contrasts that of patient M.M. who lost his sight due to a chemical accident at the age of 3. When M.M was 43 years old he got a stem cell transplant to restore his sight. M.M very much enjoyed living in the visual world, adapted well and continues to master his new abilities. An important lesson to learn from these two cases is that it takes a long time for the brain to get used to processing this new kind of information. Furthermore, it takes motivation and patience to handle such drastic changes to daily life. More generally speaking, gaining back any sort of key ability (not just vision) is intense and it is not always an easy process to endure. It is important to judge the expectations of the patient as well as provide a solid network of coping strategies in order to facilitate a functional recovery. As scientific research finds new and inventive ways to cure physical disabilities, psychological resources are needed for an effective recovery. It should be seen as essential as the medical procedure itself.

Lisa Kirsch
McGill University

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