Abstract
Purpose :
To determine the characteristics of visual field (VF) defects in subjects with primary angle closure glaucoma (PACG); and to assess differences in point-wise and Glaucoma Hemifield test (GHT) zones between the superior and inferior hemi-fields.
Methods :
We recruited 270 subjects with PACG. Point-wise total deviations (TD) and pattern deviations were extracted from the VF (program 24-2 SITA-Standard, model 750, Humphrey Instruments, Dublin, CA) printouts. Patients were excluded if they had unreliable VFs (defined as fixation losses > 20% and false positive and negative responses >33%), had undergone 10-2 VF testing, and had VF defects not typical of glaucoma as defined in “Classification of VF abnormalities in the Ocular Hypertension Treatment Study (OHTS)”. VF severity was stratified based on MD; ≤-12.01 indicating severe VF loss, -6.01 – -12.00 indicating moderate VF loss and ≥-6.00 indicating mild VF loss. VF defects were characterized according to the OHTS classification scheme. All dB values were anti-logged prior to statistical analyses. Mean TDs in GHT zones were calculated within each stage. Paired samples t-test was used to assess differences between the 26 paired points in the VF, as well as the 5 GHT zones for each severity stage.
Results :
Of 270 subjects recruited, 218 (80.7%) were included in the analysis. Mean age of the subjects was 65.0±8.6 years (range: 41-90 years) with slight male predominance (52.3%). Age and gender distribution was similar across the severity levels. Partial arcuate was the most common defect in mild and moderate stages (39.3% and 39.7%, respectively) whereas the most common VF defect for severe cases was biarcuate (30.3%). The superior hemi-field GHT zone 2 in the mild stage and superior hemi-field GHT zones 1 and 2 in the moderate stage were more severely affected (all p<0.05); while in the severe cases, all the zones in the superior hemi-field were significantly impaired (all p<0.05) compared to the inferior VF. Likewise, in point-wise hemi-field comparisons, significant impairment of the superior VF was noted across the severity stages.
Conclusions :
In PACG, there was greater impairment in the superior VF across the severity spectrum, and the hemi-field differences increased with worsening disease severity. The inferior VF areas were relatively less affected.
This is an abstract that was submitted for the 2016 ARVO Annual Meeting, held in Seattle, Wash., May 1-5, 2016.