Morphological differences between two types of Bruch's membrane defects in pathologic myopia.

PURPOSE: To investigate morphological differences between two types of Bruch's membrane (BM) defects-patchy atrophy (PA) and CNV-related macular atrophy (CNV-MA)

METHODS

Eyes presenting with PA or CNV-MA were included. Scleral thickness (ST), choroidal thickness (CT), and scleral morphological characteristics were obtained by swept-source optical coherence tomography (SS-OCT). Fundus photographs were performed to measure the size of PA and CNV-MA lesions.

RESULTS

Among a total of 167 eyes evaluated, 106 eyes had PA and 61 eyes had CNV-MA. In addition, dome-shaped macula (DSM) was identified in 20 (18.87%) and 10 (16.39%) eyes among PA and CNV-MA, respectively. The eyes of CNV-MA without DSM showed a thicker subfoveal ST (278.61 ± 56.17 vs 231.58 ± 66.09 mm, P < 0.001), a thinner subfoveal CT, and a higher rate of scleral perforating vessels (70.6% vs 50.0%, P = 0.021) when compared with those of PA without DSM. The size of PA/CNV-MA lesions was associated with CT in eyes without DSM. However, it was only associated with bulge height in eyes with DSM (r = 0.5, P = 0.013).

CONCLUSIONS

The eyes with CNV-MA had a thicker sclera than those with PA, which add another evidence to indicate the absence of the progressive relationship between two types of BM defects. The enlargement of lesions in BM defects between eyes with and without DSM may be caused by different mechanical forces. SS-OCT, which focuses on scleral and choroid morphology, may be necessary for more accurate classification of pathologic myopia.