Correlation of pattern of visual field loss by perimetry and anterior chamber angle parameters by anterior segment optical coherence tomography in primary angle-closure glaucoma

Abstract

Purpose: To correlate and analyze the pattern of the visual field (VF) defects by perimetry and anterior chamber angle parameters by AS-OCT in primary angle-closure glaucoma (PACG) across varied severity levels on presentation to a tertiary eye care center.

Methods: This was a cross-sectional study, which included 323 eyes of clinically diagnosed cases of PACG. Glaucoma severity was categorized according to mean deviation (MD) as mild (-6.00 dB or more), moderate (-6.01 to -12.00 dB), and severe (-12.01 to -30.00 dB). AS-OCT measured the nasal (N) and temporal (T) angle opening distance at 500 μm (AOD 500) and 750 μm (AOD 750), anterior chamber angle (ACA), lens vault (LV), and anterior chamber width (ACW). The VF severity was then correlated with the AS-OCT parameters using statistical analysis.

Results: The mean age ± standard deviation (SD) of the patients included in the study was 56.03 ± 8.6 years, with a 1:1.2 gender ratio. The number of eyes with mild, moderate, and severe VFs were 140 (43.3%), 88 (27.24%), and 95 (29.41%), respectively. There was no statistically significant correlation in the mean anterior chamber angle parameters (AOD 500, AOD 750, ACA 500, ACA 750, LV, ACW, and axial length (AL)) among the groups. However, the correlation between AOD 500 and LV thickness was found to be significant (P = 0.0000) with a negative Spearman's rank correlation coefficient (r = -0.3329).

Conclusion: The ACA parameters obtained by AS-OCT along the horizontal axis after elimination of pupillary block by laser peripheral iridotomy do not correlate and cannot be used to assess the disease severity of PACG.

Keywords: AS-OCT; Anterior chamber angle parameters; mean deviation; primary angle-closure glaucoma; visual field defects.

Figure 1

Pattern of visual field defects in mild, moderate, and severe groups

Figure 2

(a) Correlation between mean deviation and lens vault, (b) correlation between mean deviation and angle opening distance at 500 μm from the scleral spur, (c) correlation between mean deviation and angle opening distance at 750 μm from the scleral spur, (d) correlation between mean deviation and angle chamber angle at 500 μm from the scleral spur, (e) correlation between mean deviation and angle chamber angle at 750 μm from the scleral spur, (f) correlation between angle opening distance at 500 μm from the scleral spur and lens vault