Question

Case 2: An 88-year-old woman was seen by an ophthalmologist at an eye clinic in Toronto, complaining about itchy, burning eyes. An examination of the cornea revealed dry patches on the surface of the eye, consistent with xeropthalmia. The patient reported having food intolerances for the last 20 years and following a strict "diet" consisting of rice, canned tuna and vitamin B supplements. Serum retinol levels were found to be extremely low. The doctors prescribed megadoses of vitamin A which reversed the xeropthalmia within a few weeks.

Answer 1

2. keratin

The dry patches formed on the patients cornea are due to clumps of keratin debris that build up in patients suffering from xeropthalmia.

3. beta-carotene

The main form of vitamin A in fruits and vegetables is beta-carotene.

4. cis-Retinal

Cis-Retinal is the form of vitamin A involved in the visual cycle.