Abstract
Purpose:
To compare recommended functional and structural screening tests for hydroxychloroquine (HCQ; Plaquenil) related retinal toxicity.[1]
Methods:
Thirty six eyes of 36 patients on HCQ therapy were included in the study. Subjects with refractive errors exceeding +/-5 DS, significant cataract, age-related macular degeneration or glaucoma were excluded. Each patient had a complete ophthalmologic examination and the following recommended tests: 1. 10-2 and/or 24-2 automated visual fields (HFA, CZM); 2. horizontal line scans through the fovea obtained with spectral domain optical coherence tomography (SD-OCT; Spectralis Heidelberg Eng.); 3. short wavelength fundus autofluorescence (SW-FAF), and 4. multifocal electroretinography (mfERG; VERIS EDI). For the mfERG, the 103-hexagon P1 amplitude response densities were analyzed by averaging the 103 responses into six concentric rings, and R5 ring ratios were calculated using the R5 ring response as the “reference ring” and dividing by all other ring response amplitudes (R1 - R6).[2,3,4] The ratios of R5 to each of the other rings were compared to 95% CIs derived from control eyes.
Results:
Of the 36 patients, 16 had used HCQ for more than 5 years, 10 with a cumulative dose >1000 g. Only 6 of these 16 patients had visual field abnormalities; i.e. central and/or pericentral defects. Four of these patients with visual field abnormalities showed loss of the inner segment ellipsoid band (aka IS/OS junction) on SD-OCT foveal line scans, but only 2 had areas of hyperautofluorescence on SW-FAF. However, 10 of the 16 patients, including 5 of the 6 with visual field abnormalities, had mfERG ring ratio values outside the 95% CIs. Eight of these patients had used HCQ for >10 years with a cumulative dose >1000 g.
Conclusions:
None of the four of the recommended tests identified all cases of HCQ related retinal toxicity. However the most sensitive test appears to be the mfERG. 1. Marmor MF et al. Ophthalmology. 2011;118:415. 2. Lyons JS, Severns ML. Doc Ophthalmol. 2009;118:29. 3. Hood DC et al. Doc Ophthalmol. 2012;124:1. 4. Adam MK et al. BJO 2012;96:723.
Keywords: 509 electroretinography: clinical •
758 visual fields •
503 drug toxicity/drug effects