Fundus morphological characteristics assesment in high myopia patients with or without posterior scleral staphyloma by optical coherence tomography

To observe the morphological characteristics of posterior scleral staphyloma (PSS) with or without macular retinoschisis (MRS) using optical coherence tomography (OCT). Additionally, the incidence and severity of other pathologic myopic maculopathy associated with posterior scleral staphyloma was also evaluated.

General information and OCT imaging data from 440 patients with posterior scleral staphyloma (PSS) and the PSS curvature > 20×10^-3 μm^-1 were collected. These patients visited the Department of Ophthalmology at the First Affiliated Hospital of Harbin Medical University from January 2013 to June 2021. The obtained OCT images of PSS were analyzed using the Image J software to measure the curvature along the Bruch's membrane. The measured curvature was divided into four levels using the quartile method. The classification of macular retinoschisis (MRS) was based on the anatomical structure of the retina and the location of macular retinoschisis. Patients with PSS accompanied by MRS were assigned to the MRS group, while PSS patients without MRS were assigned to the non-MRS group. Additionally, typical OCT changes in other pathologic myopic maculopathy diseases, such as myopic choroidal neovascularization (mCNV), myopic traction maculopathy (MTM), and myopic foveoschisis (MF), were recorded and evaluated.

A total of 615 eyes (328 right eyes, 287 left eyes) from 440 patients (80 males and 360 females) were recruited in this study. The MRS group consisted of 159 patients (36.1%) with 190 eyes (30.9%), while the non-MRS group consisted of 281 patients (63.9%) with 425 eyes (69.1%). Both groups had a significantly higher proportion of female patients compared to male patients, and the right eye was more commonly affected than the left eye. In the MRS group, the prevalence of MRS increased progressively with the severity of PSS. Among the common posterior pole diseases, epiretinal membrane had the highest prevalence (33.2%), while lamellar macular hole had the lowest prevalence (5.3%). In the non-MRS group, the proportion of PSS in each group decreased progressively (except for an equal prevalence in the third and fourth levels) with increasing severity of PSS. Among the common posterior pole diseases, choroidal neovascularization had the highest prevalence (41.4%), while lamellar macular hole had the lowest prevalence (6.5%). When comparing the two groups, there were no significant differences in age, gender, and eye distribution. The MRS group had a higher prevalence of macular schisis, retinal detachment, and dome-shaped macula (17.9%, 14.2%, 14.8%) compared to the non-MRS group (11.3%, 9.2%, 9.6%). The non-MRS group had a significantly higher prevalence of choroidal neovascularization (41.4%) compared to the MRS group (12.6%), while there were no significant differences in the prevalence of epiretinal membrane and lamellar macular hole between the two groups.

The prevalence of MRS increased progressively with the severity of PSS, and the MRS occurrence was positively correlated with PSS, which indicated that PSS may lead to MRS, while the proportion of PSS in each group decreases gradually with the severity of PSS in the non-MRS group decreased progressively (except for an equal prevalence in the third and fourth levels). In the MRS group, outer macular retinoschisiss were most relevant to posterior scleral staphyloma, and the prevalence of macular holes and retinal detachments was higher in the MRS group compared to the non-MRS group, indicating that MRS may further turn into complications such as macular holes and retinal detachments, which can significantly affect vision or lead to blindness. The prevalence of choroidal neovascularization (CNV) was significantly higher in the non-MRS group compared to the MRS group, suggesting that PSS with lower severity is more prone to develop into CNV. Dome-shaped macula (DSM) seems to play a protective role in the development of pathologic myopia, and abnormal changes in posterior scleral staphyloma curvature may be an important factor affecting the development and shape of DSM.