COMPARATIVE STUDY OF RNFL THICKNESS USING SPECTRAL DOMAIN OCT AND VISUAL FIELD ANALYSIS USING HUMPHREY FIELD ANALYSER IN CASES OF POAG

Abstract

Purpose: To compare RNLF structural changes by Spectral Domain- OCT and functional visual eld defects by automated perimetry in Primary Open Angle Glaucoma cases Materials And Methods: A prospective and comparative study was conducted to quantitatively measure the peripapillary retinal nerve ber layer thickness using SD-OCT and compared it with eld changes plotted by Humphrey Field analyser 24-2. The study was conducted at the department of Glaucoma of a tertiary eye care hospital for a period of one year. 60 eyes of 30 patients who diagnosed to have POAG between the age group of 40-65 were included in the study. Patients having substantial media opacity, Retinal pathology and who underwent intra ocular surgeries were excluded from the study. Informed consent obtained from patients who were included in the study. All were examined using Slit lamp, Snellen's chart, Applanation tonometer, Gonioscope, 90 D slit lamp biomicroscope to study Fundus oculi. Fields were plotted using Humphrey eld analyser 24-2 , RNFL thickness measured using SD-OCT. Results: 60 eyes of 30 patients 19 were males 11 were females. 14(23.33%) eyes showed normal visual elds but there was thinning of RNFL was noted in SD-OCT. 41 eyes (68.3%) had visual eld defects which corresponded to thinning of RNFL in that quadrant. 5 eyes (8.3%) showed advanced eld changes and had corresponding thinning of RNFL in that quadrant. Discussion: Results of this study shows a signicant difference in RNFL thickness among all three grades of glaucoma. It was observed that the average RNFL thickness value in moderate glaucoma (66.34 microns) and all quadrant thickness values were similar to Sihota et al study (RNFL-66.07 microns). The mean RNFL thickness +/- Sd (58 +/-5.52) in advanced glaucoma of present study were closely similar with the ndings of Sihota et al study (53.65 +/-14.2). Conclusion: It is concluded that RNFL thickness changes corresponds to Field changes plotted on Humphrey eld analyser in moderate glaucoma. Even in mild cases changes RNFL thickness is noted even though the elds plotted on Humphrey eld analyser doesn't show any changes. So RNFL thickness can be taken as Pre perimetric changes as diagnostic criteria for the diagnosis of POAG.