Ultrawide-Field OCT to Investigate Relationships between Myopic Macular Retinoschisis and Posterior Staphyloma

Purpose: To investigate the relationships between myopic macular retinoschisis (MRS) and posterior staphylomas and to reveal the characteristics of other retinal lesions associated with MRS. Design: Retrospective, observational case series. Participants: Seven hundred twenty-nine eyes of 420 patients with high myopia, which was defined as myopic refractive error of more than -8.0 diopters or an axial length longer than 26.5 mm. Methods: Highly myopic eyes were examined by ultrawide-field (UWF) swept-source (SS) OCT with scan width of up to 23 mm and scan depth of 5 mm. The OCT features of MRS and posterior staphylomas and their spatial relationship were examined in UWF SS OCT images. Main Outcome Measures: Associations between MRS and staphylomas. Results: In 729 eyes with mean axial length of 30.2 +/- 2.1 mm, posterior staphyloma was detected in 482 eyes (66.1%) and MRS was detected in 136 eyes (18.7%). All 136 eyes with an MRS showed outer retinoschisis, and 40 eyes (29.4%) also showed inner retinoschisis. Posterior staphyloma was detected significantly more frequently in eyes with MRS (117/136 [86.0%]) than in eyes without MRS (365/593 [61.6%]; P < 0.001). In all eyes with both staphyloma and outer retinoschisis, the area of the outer retinoschisis was restricted to the area within the staphyloma. In 1 of the 19 eyes with outer retinoschisis but without staphyloma, the outer retinoschisis extended beyond the range of the scanned fundus area. Among the 40 eyes with inner retinoschisis, the inner retinoschisis was located within the region of the outer retinoschisis in 39 eyes (97.5%). In all eyes with inner retinoschisis, retinal lesions causing an inward-directed tractional force were found within the area of the inner retinoschisis. Conclusions: In highly myopic eyes, the sites of the MRS and staphylomas were spatially related to each other. Posterior-directed force in association with staphylomas, and an inward-directed force resulting from epiretinal membranes or vitreoretinal attachments, may act as causative factors for MRS. However, the exact mechanisms related to the development of an MRS are probably diverse and complex. (C) 2018 by the American Academy of Ophthalmology