Utility of ganglion cell complex analysis in early diagnosis and monitoring of glaucoma using a different spectral domain optical coherence tomography

Abstract

Purpose: To determine the importance of ganglion cell complex (GCC) analysis as a parameter for early diagnosis of glaucoma and for following glaucoma progression and to compare glaucoma progression with conventional visual field analysis using a different type of spectral-domain optical coherence tomography (SD-OCT). Materials and methods: Two hundred eyes including 68 normal eyes, 70 eyes with pre-perimetric glaucoma and 62 eyes with perimetric glau coma were analyzed in this prospective study undertaken during Jan 2013 to Dec 2013 in a tertiary ophthalmology institute. Automated visual field examination was done to group the subjects in above three categories. The thicknesses of the GCC and retinal nerve fiber layer (pRNFL) were measured using Topcon model 2000 version 7.1 SD-OCT images and compared. The statistical analysis was carried out by z-test. Results: The average GCC was thickest in the normal group and the thickness decreased as the severity of glaucoma increased. The mean macular GCC at the start and end of the study in pre-perimetric (94.86 ± 8.31, 90.74 ± 8.46) and perimetric (82.48 ± 13.21, 79.80 ± 12.88) eyes was lower than those in normals (102.70 ± 7.19, 101.82 ± 7.42). Conclusion: Majority of the studies done on GCC analysis have used the Cirrus OCT (Zeiss). Our study has used the Topcon model 2000 version 7.1 to show that irrespective of the machine used, GCC analysis definitely plays an important role. To detect pre-perimetric glaucoma and may show progression earlier than pRNFL in pre-perimetric glaucoma.