The Relationship of Hydroxychloroquine Retinopathy Progression to Stage at Cessation of Therapy

To examine the progression of hydroxychloroquine retinopathy (HCR) from the time of drug cessation to the last follow-up.

Retrospective, consecutive case series SUBJECTS: 17 patients with HCR in whom drug was stopped and follow-up maintained.

Charts, visual fields, and retinal images were reviewed. Four ancillary studies were investigated: 10-2 visual fields (10-2 VF), multifocal electroretinography (mfERG), spectral domain optical coherence tomography (SD-OCT), and fundus autofluorescence (FAF) imaging. Retinopathy was graded as none, early, and advanced.

Progression of retinopathy by the four test methods.

Of the 17 patients, the numbers with at least two follow-up studies to allow comparison for progression were 17, 8, 16, and 9 for 10-2 VF, mfERG, SD-OCT, and FAF, respectively. Median follow-ups were 25, 22, 41, and 37 months for 10-2 VF, mfERG, SD-OCT, and FAF, respectively. The proportions of eyes with no retinopathy at drug cessation that progressed were 0/0, 3/5, 0/0, and 2/6 for 10-2 VF, mfERG, SD-OCT, and FAF, respectively. The proportions of eyes with early retinopathy that progressed were 4/6, 0/6, 2/15, and 3/7 for 10-2 VF, mfERG, SD-OCT, and FAF, respectively. The proportions of eyes with advanced retinopathy that progressed were 16/20, 0/5, 10/17, and 5/5 for 10-2 VF, mfERG, SD-OCT, and FAF, respectively. Progression of retinopathy was seen in cases without retinal pigment epithelium loss at the time of drug cessation. Not all ancillary studies show retinopathy at the time of diagnosis of HCR. Multifocal ERG shows a floor effect. Once response densities are low, detecting further progression of toxicity by this modality is not possible. A greater breadth of retinopathy progression is possible with 10-2 VF, SD-OCT, and FAF.

If HC is stopped when decreased reflectivity of the parafoveal ellipsoid zone is detected by SD-OCT, the probability of retinopathy progression is low. The cut point at which progression of retinopathy is acknowledged to be likely despite drug cessation needs to be moved earlier to discontinuity of the ellipsoid zone.