A Morphologic Model of Glaucomatous Damage to the Macular Ganglion Cell Layer in Myopic Eyes.

Abstract

Prcis: A model of glaucomatous progression based upon patterns of macular ganglion cell layer (GCL) damage can help clinicians distinguish between glaucomatous damage and other causes of GCL abnormalities in eyes with high myopia.

Purpose: To evaluate a model-based approach for identifying glaucomatous macular ganglion cell layer (GCL) damage in highly myopic eyes by analyzing characteristic loss patterns.

Materials and methods: This retrospective observational study involved optical coherence tomography scans of 72 myopic eyes (axial length>25 mm), including 15 normal control eyes and 57 eyes with glaucoma or glaucoma suspects. The mean axial length was 27.09±1.61 mm (range, 25.13-35.77 mm). The mean refractive error was -7.81±2.70 D in 46 eyes without prior refractive or cataract surgery. The loss pattern in the thick donut-shaped region of the macular GCL thickness map was compared with a model predicting glaucomatous damage patterns, suggesting damage originates temporally and progresses nasally.

Results: As predicted, the temporal sectors of the 57 patients' GCL donuts showed the highest number of abnormalities significant at 5% (temporal superior: 28, temporal inferior: 37), followed by the middle sectors (superior: 26, inferior: 30), and then nasal sectors (nasal superior: 24, nasal inferior: 27). Among 3 eyes deviating from the model, 2 showed nasal defects without temporal involvement, while 1 showed an epiretinal membrane (ERM)-induced artifact. Of the 24 eyes with macular lesions (most commonly ERM in 19), 21 were diagnosed with glaucoma or glaucoma suspects. Of these, 20 conformed to the model, except 1.

Conclusions: The proposed model of glaucomatous damage patterns in macula GCL is applicable to myopic eyes, even with coexisting macular pathology. In cases deviating from the model, clinicians are advised to seek causes besides glaucoma.