Sensitivity and specificity for detecting early glaucoma in eyes with high myopia from normative database of macular ganglion cell complex thickness obtained from normal non-myopic or highly myopic Asian eyes.

PURPOSE

We aimed to determine the sensitivity and specificity of the normative database of non-myopic and highly myopic eyes of the macular ganglion cell complex (mGCC) thickness embedded in the NIDEK RS-3000 spectral-domain optical coherence tomography (SD-OCT) for detecting early glaucoma in highly myopic eyes.

METHODS

Forty-seven highly myopic eyes (axial length ≥26.0 mm) of 47 subjects were studied. The SD-OCT images were used to determine the mGCC thickness within a 9-mm diameter circle centered on the fovea. The sensitivity and specificity of the non-myopic database were compared to that of the highly myopic database for distinguishing the early glaucomatous eyes from the non-glaucomatous eyes. The mGCC scans were classified as abnormal if at least one of the eight sectors of the significance map was < 1 % of the normative thickness.

RESULTS

Twenty-one eyes were diagnosed to be non-glaucomatous and 26 eyes to have early glaucoma. . The average mGCC thickness was significantly thinner (80.9 ± 8.5 μm) in the early glaucoma group than in the non-glaucomatous group (91.2 ± 7.5 μm; p <1 × 10(-4)). The sensitivity was 96.2 % and specificity was 47.6 % when the non-myopic database was used, and the sensitivity was 92.3 % and the specificity was 90.5 % when the highly myopic database was used. The difference in the specificity was significant (p < 0.01).

CONCLUSIONS

The significantly higher specificity of the myopic normative database for detecting early glaucoma in highly myopic eyes will lead to fewer false positive diagnoses. The database obtained from highly myopic eyes should be used when evaluating the mGCC thickness of highly myopic eyes.