COMPARISION OF VISUAL FIELD DEFECTS IN PRIMARY OPEN ANGLE GLAUCOMA WITH FREQUENCY DOUBLING PERIMETRY(FDP) VERSUS STANDARD AUTOMATED PERIMETRY(SAP)

Dr. Sunil Verma*

ABSTRACT

Objectives: To compare the efficacy of FDP to detect early visual field defects changes as compared to SAP in POAG patients. Method: Non randomized, cross-sectional study included 70 diagnosed patients of POAG and 70 healthy controls of different age groups and of either sex attending the glaucoma clinic of ophthalmology department. Patients with best corrected visual acuity > 20/30, refractive error < ±6 dioptres sphere and < ± 2 dioptres cylinder and with baseline IOP ≥ 21mm of Hg in diurnal curve were included, while patients with history of any previous ocular surgery, significant central lens opacities, retinal disease producing visual field defects, ocular hypertension, normal tension glaucoma, primary angle closure glaucoma, were excluded from the study. Participants underwent examination with Standard Automated Perimetry (SAP) with Humphrey Visual Field Analyzer using 30-2 SITA Standard and Frequency Doubling Technology Perimetry (FDT) with Humphrey Matrix using 30-2 full threshold using ZEST strategy. Result: In our study we found FDP is a quick procedure (Mean test duration was significantly shorter with FDT Matrix as compared to SAP SITA (326.70 ± 17.70 vs. 380.50 ± 72.00 seconds, respectively; P<0.001) and detect early visual field defects. But FDT does not detect larger defects as compared with SAP SITA. The defects detected by FDT Matrix are smaller and deeper i.e., detected by greater light intensity than SAP SITA. Also there was no significant correlation found between the sensitivity measured by the two methods in the various quadrants. Conclusion: FDT’s major contribution may be as a complement to SAP for detecting visual field loss but not as a replacement of SAP.

Keywords: Frequency doubling perimetry; Standard automated perimetry; Primary open angle glaucoma.