Clinical and morphological comparisons of idiopathic macular holes between stage 3 and stage 4

Purpose To compare clinical and morphological differences in idiopathic macular holes (IMHs) between stage 3 and stage 4. Methods In this retrospective cross-sectional observational study, patients with stage 3 and stage 4 IMHs based on Gass’s classification in 1988 were enrolled. Horizontally and vertically, optical coherence tomography (OCT)-based parameters including minimum linear diameter (MLD), basal diameter (BD), and macular hole height ( H ) were measured; fluid cuff (FC), diameter hole index (DHI), macular hole index (MHI), traction hole index (THI), and hole form factor (HFF) were calculated. Afterwards, stage 3 IMHs smaller than 400 μm were excluded according to Gass’s classification in 1995. Clinical features, such as age, duration of symptoms, and baseline best-corrected visual acuity (BCVA), and OCT parameters were compared respectively between two stages based on both classifications. Results Given classification of 1988, stage 3 IMHs had significantly shorter duration of symptoms ( P = 0.020) and smaller horizontal BD ( P = 0.041). Horizontally and vertically, MLD ( P = 0.001, 0.004 respectively), DHI ( P = 0.032, 0.021 respectively), and HFF ( P = 0.032, 0.017 respectively) were significantly smaller and THI ( P = 0.011, 0.020 respectively) was significantly larger in stage 3 holes. Clinical features like age and baseline BCVA showed no significant differences. When staged by classification of 1995, IMHs of the two stages shared similar features. Conclusions Stage 3 IMHs, instead of owning shorter duration of symptoms and smaller diameters, share similar clinical and morphological features with stage 4 IMHs according to Gass’s classification in 1995, which excludes IMHs smaller than 400 μm from stage 3 compared to his 1988 version.