OSLI Retina

May 2020

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May 2020 · Vol. 51, No. 5 287 for most retinitis pigmentosa and aroused suspicion of acquired disease, although there were no signs of inflammation, and vitamin A deficiency seemed un- likely in a well-developed vegetarian child. SERENDIPITY Vitamin A deficiency was my first thought with a poor rod ERG in the absence of b-wave timing de- lay or degenerative changes, but I was put off by the vegetarian diet and her good health. I told the family I would reflect on other possible causes and studies. Almost as an afterthought as they were leaving the office, I asked the mother, "I assume she is getting plenty of vegetables in her diet?" I was taken aback when the mother replied that her daughter does not like vegetables and only eats carbohydrates. PROOF The likelihood of vitamin A deficiency was obvi- ous, and blood levels were ordered. The initial level was low-normal at 29.9 µg/dL (lab range: 12.8 to 81.2), but we still suspected deficiency because of the ERG. The patient did occasionally eat some vegetables that may have varied her blood levels. She was asked to begin 5,000 U/day vitamin A supplementation and return in a month for repeat the ERG and blood lev- els. The patient came back in 6 weeks, having used the vitamin A for about 1 month (somewhat irregu- larly); she had also returned to a more conventional vegetarian diet. She was bright enough to recognize the importance of diet to her vision. On her return, VA was still reduced at clinic reg- istration; however, with encouragement (even after dilatation), she could read 20/30 letters with confi- dence. Interestingly, her vitamin A levels were essen- tially unchanged (28.2 µg/dL), and her dark adapta- tion threshold improved only slightly. I suspect this related to the timing and amounts of her vitamin A intake relative to testing. However, her ERG (Figure 2) improved dramatically, with both rod and cone values rising near our typical norms in amplitude. The parents were much relieved to see her deficits reversed and the specter of retinitis pigmentosa or permanent damage removed. DISCUSSION Vitamin A deficiency is a major cause of blindness in the third world when evolving to xerophthalmia. However, it is a rare disease in developed countries, except when there is obvious malabsorption from bar- iatric surgery, medical disorders, or psychiatric con- ditions such as autism that can lead to a restricted or faddish diet. 2,3 It is very unusual in middle-class children with- out obvious psychologic issues or poor nourishment. This case demonstrates that dietary aberrations are not always associated with obvious malnutrition, and it highlights the importance of asking explicitly about Figure 1. Fundus autofluorescence and spectral-domain optical coherence tomography at the initial exam, showing no abnormalities.

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