Purpose: To investigate the effectiveness of magnification correction (MC) and long axial length normative database (LAL-NDB) on the diagnostic ability of macular ganglion cell complex (GCC) thickness for early glaucoma in eyes with long axial length.
Subjects and methods: Eyes with AL ≥ 26 mm (56 eyes of 56 cases with early primary open angle glaucoma [including 11 patients with preperimetric glaucoma, Humphrey visual field mean deviation> -6 dB］and 72 healthy eyes) were assessed. Macular GCC thickness was measured using spectral-domain optical coherence tomography (RS-3000, NIDEK, Aichi, Japan) and compared with a regular normative database (RNDB, spherical equivalent ≥ -6 D) or LAL-NDB (axial length ≥ 26 mm). Both NDBs were constructed with or without MC, and glaucoma diagnostic abilities were compared. The study eyes were tested against NDBs in the matched condition in terms of MC. Eyes with GCC thickness below the 95th percentile in at least one of 10 GCC mean thickness analysis regions were diagnosed as having glaucoma.
Results: Using RNDB without MC, the sensitivity and specificity were 92.9% and 61.1%, respectively. The sensitivity did not change significantly by switching to the three other NDBs, but the specificity significantly improved by switching to LAL-NDB with or without MC (p=0.0006 and 0.006, respectively).
Conclusion: LAL-NDB, irrespective of MC, effectively improves the specificity of macular GCC thickness for detecting early glaucoma in eyes with long axial length.
Nippon Ganka Gakkai Zasshi (J Jpn Ophthalmol Soc) 124: 539-548, 2020.