Diagnostic Accuracy of a Humphrey 24-2C Protocol for Simultaneous Parafoveal and Pericentral Hydroxychloroquine Retinopathy Screening

Abstract

Purpose To evaluate the diagnostic performance of the Humphrey 24-2C visual field (VF) protocol compared with the standard 10-2 and 30-2 strategies for detecting parafoveal and pericentral hydroxychloroquine (HCQ) retinopathy. Design Retrospective cross-sectional diagnostic validity assessment. Participants In total, 1081 patients (2104 eyes) receiving HCQ therapy without confounding ocular pathology were screened for retinopathy at a tertiary center between January 2021 and April 2025. The cohort included 1011 patients without retinopathy and 70 with confirmed retinopathy. Methods Participants underwent swept-source OCT, fundus autofluorescence, and Humphrey VF testing using the 10-2 Swedish Interactive Thresholding Algorithm (SITA) Fast, 24-2C SITA Faster, and/or 30-2 SITA Fast protocols. Retinopathy was defined according to the American Academy of Ophthalmology guidelines as the presence of at least 2 abnormalities on structural and/or functional tests. Sensitivity and specificity of each VF protocol were evaluated against OCT as the gold standard. Main Outcome Measures Sensitivity and specificity of the 10-2, 24-2C, and 30-2 protocols. Results In early cases without definitive OCT changes (ellipsoid zone loss), parafoveal retinopathy was detected in 71.4% with the 10-2, 57.1% with the 24-2C, and 28.6% with the 30-2. Early pericentral defects were detected on the 24-2C and 30-2 in 57.1% versus 9.5% on the 10-2. The 24-2C’s sensitivity matched that of the 10-2 for parafoveal disease (94.7%) and was comparable with the 30-2 for pericentral disease (90.8% vs 85.5%). Receiver operating characteristic analysis using the 24-2C yielded areas under the curve of 0.844 for mean deviation, 0.881 for pattern standard deviation, and 0.887 for VF index in detecting retinopathy. The mean test duration for 24-2C was 164.8 ± 40.2 seconds, significantly shorter than for 30-2 (253.2 ± 79.1 seconds; P < 0.001) among eyes that underwent both tests; among those tested with both 10-2 and 24-2C, 24-2C was also faster than 10-2 (237.4 ± 64.8 seconds; P = 0.001). Conclusions The Humphrey 24-2C protocol offers a reliable, time-efficient, and single-test solution for screening both parafoveal and pericentral HCQ retinopathy, with diagnostic performance comparable with that of the 10-2 protocol for parafoveal retinopathy and 30-2 protocol for pericentral one. Financial Disclosure(s) Proprietary or commercial disclosure may be found in the Footnotes and Disclosures at the end of this article.