Evaluation of macula, choroid thickness and the changes of macula layers using oct segmentation in patient with inferior oblique overaction

PURPOSE: Evaluation of central macular and subfoveal choroid thickness using Spectral Domain Optical Coherence Tomography (SD-OCT) and EDI-OCT (Enhanced depth imaging-OCT) and macular layers by performing OCT segmentation analysis of the patients with inferior oblique muscle overaction (IOOA) by comparing with the fellow eyes. MATERIAL and METHOD: Between July 2017 and October 2019, 45 patients with inferior oblique muscle overaction who were followed up at the Department of Ophthalmology in Adiyaman University Hospital were evaluated retrospectively. Patients with unilateral primary inferior oblique overaction were included in the study. Detailed ophthalmologic examinations of all patients were performed. Eighty-one eyes of 45 patients with unilateral IOOA with study criteria were included in the study. Thirty-nine (48.9%) of 81 eyes showed IOOA. Eyes with inferior oblique overaction are IOOA positive, other eyes of the patients (without IOOA) are included in the control group as IOOA negative and 2 main groups were created. Eyes with IOOA were separated into 3 subgroups: only IOOA, IOOA with ET and IOOA with XT. Also, eyes with IOOA were separated into 2 subgroups in terms of the hypertropia grade at the adduction position by between +1 and +4 grades; +1 and +2 were mild IOOA, +3 and +4 were severe IOOA. Central macular thickness was measured by SD-OCT and subfoveal choroidal thickness by EDI-OCT. The thickness of each retinal layer was measured by SD-OCT in the central 1, 3, 6 mm areas of all cases as defined by ETDRS (Early Treatment Diabetic Retinopathy Study). Heidelberg segmentation was performed to define different layers of macula. RESULTS: Inferior oblique muscle overaction was present in 42 (51.9%) eyes, 39 (48.1%) eyes in the control group created from the fellow eyes of the patients and the IOOA of the control group was normal. The average age of the patients is 11.42 ± 6.08 years, and the median is 9.00 (6.00-25.00) years. 51.1% (n = 23) of the patients were female. In the study group with severe IOOA, GCL+IPL showed a decrease in thickness compared to the group with mild IOOA in the macular area of 1 mm, but it was not statistically significant (p=0.059). In the group with IOOA with esotropia, OPL thickness increased compared to other groups, but it was not statistically significant (p = 0.052). CONCLUSION: Our study was planned with the hypothesis that when the inferior oblique muscle shows overaction, "morphological changes and anatomical weaknesses may occur in the macular layers and may lead to the formation of retinal pathologies" due to the inferior oblique muscle insertion near the macula. In our study, no statistically significant difference was found between central macular thickness, macular layers and subfoveal choroid thickness between groups. Our study results do not support our hypothesis. This study should be supported by histological studies on this subject. We suggest this issue to be investigated further with larger patient groups that will be compared with the healthy control group.