Angular distance between fovea, RNFL may affect glaucoma detection with GCA maps
Ganglion cell analysis maps were found to be a useful tool in detecting early glaucoma, but they lacked the ability to detect abnormal findings in glaucomatous eyes when angular distance between the fovea and retinal nerve fiber layer was substantial, according to a study.
The study authors used Cirrus high-definition optical coherence tomography (Carl Zeiss Meditec) with macular ganglion cell analysis (GCA) maps to examine its effectiveness in identifying early glaucoma.
The cross-sectional study included 131 eyes with early glaucoma and 132 healthy eyes.
Structural abnormalities were found in 105 glaucomatous eyes in the GCA sector map, 115 glaucomatous eyes in the deviation map and 104 glaucomatous eyes in the thickness map. Structural abnormalities were found in 28 healthy eyes in the GCA sector map, 37 healthy eyes in the deviation map and 20 healthy eyes in the thickness map.
GCA maps showed healthy eyes with abnormal findings had a higher degree of myopic refractive error (P < .05).
“Angular distance of RNFL defect was the only significant factor in regression models and in all GCA sector, deviation and thickness maps,” the study authors said. “This finding suggests that the angular distance of RNFL defect is the most important factor affecting the diagnostic ability of macular GCA maps.”
Disclosure: The authors have no relevant financial disclosures.