Abstract
Purpose :
Spectral domain Optical Coherence Tomography (SD-OCT) has been previously shown to be a useful modality in the detection of hydroxychloroquine toxicity both for qualitative inspection and quantitative ananlysis. OCT Minimum Intensity (MI) provides a different analysis of the OCT data to visualize photoreceptor disruption. We compare OCT MI analysis to multifocal electroretinography (mfERG) reference testing in participants with and without toxicity.
Methods :
Fifty-seven study participants (91.2% female; mean age, 55.7±10.4 years; mean duration of hydroxychloroquine treatment, 15.0±7.5 years) were divided into toxicity affected (n=19) and unaffected (n=38) groups using objective mfERG criteria. A Cirrus-HD system was used to obtain macular 512x128 cube scans and were analyzed using the OCT MI algorithm, a novel quantitative technique developed by Carl Zeiss Meditec, Inc. (Dublin, CA). The OCT MI results were analyzed in each ETDRS subfield and data for one eye of each participant was used in a t-test analysis comparing the affected and unaffected groups. A receiver operating characteristic (ROC) curve was plotted and area under the curve (AUC) was calculated for each subfield to assess the sensitivity and specificity of the OCT MI to discriminate between presence and absence of HCQ retinal toxicity.
Results :
The mean of the median OCT MI values measured in all 9 ETDRS subfields were significantly higher in the affected group compared with those of the unaffected group (median difference in MI > 3.50, P < 0.005 for all comparisons). The subfields with the greatest difference in the median OCT MI values between affected and unaffected patients were the Inner Inferior subfields (median difference MI >10.00; P<0.0001). ROC analysis of Inner Inferior subfields showed high sensitivity and high specificity (AUC= 0.997; Sensitivity=100%, Specificity= 89.5%, with MI cutoff= 54.3).
Conclusions :
Analysis of the OCT MI, especially in the Inner Inferior subfield, is an objective anatomical measure that appears to demonstrate clinically useful sensitivity and specificity for the detection of hydroxychloroquine toxicity as identified by mfERG. OCT is a widely accessible imaging modality and incorporating OCT MI analysis to patient evaluation may aid in the detection of hydroxychloroquine-induced retinal toxicity.
This is an abstract that was submitted for the 2016 ARVO Annual Meeting, held in Seattle, Wash., May 1-5, 2016.