Usefulness of photopic and scotopic microperimetry in the early diagnosis of macular toxicity secondary to hydroxychloroquine use

Abstract

Purpose : The exact mechanism of how hydroxychloroquine produces macular toxicity is still uncertain and unpredictable. That is why we propose microperimetry as a method for early detection retinal sensitivity decreased, even in patients with normal funduscopic images and without structural OCT alterations.

Methods : Microperimetry was performed using the Nidek MP3s equipment (Hiroshi, Japan) using a 13-point fovea-centered pattern, in photopic and scotopic mode in 25 eyes of 13 patients undergoing treatment with hydroxychloroquine that did not present fundoscopic alteration or structural OCT changes compatible with maculopathy. The same protocol was applied in a group of 41 eyes of 22 healthy volunteers, all of them with a corrected visual acuity of 1.0 on a decimal scale (0.00 Log Mar) and a spherical equivalent less than +/- 5.0 D. Subsequently, the data was processed using descriptive analytics, T- Student and mean difference.

Results : The chloroquine use time mean was 6.04 years (range 1-16 years), the average VA of this group is 0.04 (Log MAR), the photopic mean retinal sensitivity (MRS) in the study group was 26.75 dB (SE = 0. 14 ) while in the healthy group 29.49 dB (SE = 0.32 ) and in scotopic mode the mean in the study group was 14.5 dB (SE = 0.32), and 13.38 dB (SE = 0.28 ) in the control group, presenting a significant statistical difference (p <0.05) in both photopic and scotopic modes.
The central retinal sensitivity (CRS) also showed a significant difference in both modes (p <0.05), the average being for the study group 26.52 dB (SE = 0.8) and 29.22 dB (SE = 0.38) in the control group in photopic mode; and on the scotopic examination 10.86 dB (SE = 0.36) and 12.28 dB (SE = 0.40) for study and control group respectively.

Conclusions : The mean retinal sensitivity in patients who use hydroxychloroquine is significantly lower than MRS in persons who do not use it; in both photopic and scotopic microperimetry mode. This is why we consider that microperimetry test could be a good alternative to screen and to follow hydroxychloroquine related maculopathy.

This is a 2020 ARVO Annual Meeting abstract.