Abstract
Purpose :
We have previously shown early functional anomalies in 20% of our pediatric patients on hydroxychloroquine for various autoimmune disorders with both flash and multi-focal electroretinography, while no children showed structural changes that could explain their functional deficits (abstract published in ISCEV documenta ophthalmologica, November 2017). In adults it is well known that hydroxychloroquine toxicity is related to structural deficits as demonstrated on newer tests such as fundus autofluorescence imaging. We aimed at further investigating the macular structure of our pediatric patients on hydroxychloroquine with more sensitive autoflourescence testing of topographic damage that is currently part of the recommended screening tests in adults.
Methods :
We conducted a longitudinal, cohort study comparing 21 patients referred from the Rheumatology service. All patients had fundus autofluorescence testing using the Heidelberg system (Heidelberg Engineering, Germany). Statistics were performed using the z-score and linear regression analysis.
Results :
Baseline comprehensive ophthalmic exams were normal in all children. Fundus autofluorescence imaging was normal in all children with no areas of hyper or hypoautofluorescence in the macula. As previously reported, out of the 21 patients, 4 (19%) displayed statistically significant (p<0.05) abnormal multi-focal electroretinogram recordings with decreased P1 amplitudes (ring 1 mean was 15.5nV +/-6.46) and delayed N1 implicit times (ring 1 mean was 12.7ms +/- 1.44) at all eccentricities as compared to our normative population (normal P1 ring 1 mean was 18nV +/- 6.5 and normal N1 ring 1 was 16.2ms +/- 1.4). All patients with functional deficits had normal fundus autofluorescence results as compared to normals.
Conclusions :
Our study was not able to show structural changes with fundus autofluorescence testing that could explain the functional deficits that we previously noted with the multi-focal electroretinogram. We postulate that hydroxychloroquine initially alters the functioning of the photoreceptors prior to changing the structure of the macula. This would suggest we should put more emphasis on the functional (rather that structural) evaluation of hydroxychloroquine toxicity when detecting the first signs of retinal damage in children and young adults.
This is an abstract that was submitted for the 2018 ARVO Annual Meeting, held in Honolulu, Hawaii, April 29 - May 3, 2018.