A New Objective Parameter in Hydroxychloroquine-Induced Retinal Toxicity Screening Test: Macular Retinal Ganglion Cell-Inner Plexiform Layer Thickness
Mehmet BULUT1, Muhammet Kazım EROL1, Devrim TOSLAK1, Melih AKIDAN1, Ebru KAYA BAŞAR2, Hasan Fatih ÇAY3
1Department of Ophthalmology, Antalya Training and Research Hospital, Antalya, Turkey
2Deparment of Animal Science Biometry and Genetics Unit, Akdeniz University, Faculty of Agriculture, Antalya, Turkey
3Department of Rheumatology, Antalya Education and Research Hospital, Physical Medicine Rehabilitation, Antalya, Turkey
Keywords: Hydroxychloroquine; macula; perimetry; retinal ganglion cell; spectral-domain optical coherence tomography
Objectives: This study aims to detect hydroxychloroquine (HCQ)-induced retinal toxicity at an earlier stage through the use of spectral-domain optical coherence tomography device, especially by measuring macular retinal ganglion cell-inner plexiform layer (RGC-IPL) thickness.
Patients and methods: In this study, 92 eyes of 46 Caucasian female patients (mean age 53.6±8.1 years; range 32 to 69 years) who were taking HCQ were assigned to group 1, while 80 eyes of 40 age-matched Caucasian female control subjects (mean age 56.1±10.7 years; range 34 to 71 years) were assigned to group 2. RGC-IPL thickness and retinal nerve fiber layer thickness were measured in all subjects by Cirrus high-definition optical coherence tomography model 5000 device using macular cube 512¥128 and optic disc cube 200¥200 protocols. We performed an evaluation to see if there was any difference between the measured values of the groups. The correlation between average RGC-IPL thickness measures and cumulative dose of HCQ and duration of use was analyzed.
Results: Retinal ganglion cell-inner plexiform layer of group 1 was found to be statistically thinner than that of group 2 both on average and in all segments (superior, superonasal, inferonasal, inferotemporal and superotemporal) except inferior segment when segmented (p<0.05). Additionally, a statistically significant negative correlation was found between the average RGC-IPL thickness and cumulative dose of HCQ (r= -0.371, p=0.001) as well as the duration of use (r= -0.308, p=0.006).
Conclusion: Patients taking HCQ were found to have decreased RGC-IPL thickness at an early stage due to retinal toxicity induced by the drug. We think that measuring the RGC-IPL thickness may become an important objective in HCQ screening tests.
The authors declared no conflicts of interest with respect to the authorship and/or publication of this article.
The authors received no financial support for the research and/or authorship of this article.