Abstract:
Aim: Aim of the study was to detect early damage of the optic nerve head in patients with glaucoma with the help of blue on yellow perimetry, and to correlate the functional indices measured by blue on yellow perimetry with the structural parameters measured by optical coherence tomography.
Materials and Methods: This is a prospective cross sectional study conducted in the Department of Glaucoma, Regional Institute of Ophthalmology, and Chennai. 180 eyes of 93 subjects were screened. Out of 180 eyes, 158 eyes were glaucoma suspects who were referred with either suspicious disc, increased IOP, or with other risk factors. Complete glaucoma evaluation including standard white on white, blue on yellow perimetry, and optical coherence tomography was done, and the results were analysed.
Results: Out of 158 eyes, 137 eyes showed normal fields, 16 were borderline, five had abnormal fields in white on white (W-W) perimetry. With blue on yellow (B-Y) perimetry. 54 eyes were found to be normal, 36 eyes were borderline, and 68 eyes were abnormal. All the 137 eyes with normal fields in W-W perimetry were subjected to B-Y perimetry and analysed. 50 eyes had normal fields, 29 eyes had borderline fields, and 58 eyes had abnormal fields. Out of 16 eyes with borderline fields in W-W perimetry, 10 were abnormal, five were borderline and one turned out to be normal B-Y perimetry. All five eyes with abnormal fields in W-W Perimetry were abnormal in B-Y Perimetry. Retinal nerve fibre layer (RNFL) values by OCT and global indices in blue on yellow perimetry had a statistically significant correlation.
Conclusion: Blue on Yellow perimetry detects glaucomatous damage earlier in suspected glaucoma patients, compared to standard white on white perimetry. The functional parameters presented in the form of global indices in B-Y perimetry correlate with structural parameters given by optical coherence tomography.
