Abstract
Purpose :
To identify the clinical, structural and genetic associations of patients with advanced visual field loss at presentation.
Methods :
Patients of Chinese ancestry with POAG were recruited for the study. Baseline clinical characteristics such as age, gender, visual acuity (VA), intraocular pressure (IOP), central corneal thickness (CCT), vertical cup disc ratio (VCDR) and visual field (VF) mean deviation (MD) value were documented. Structural optic nerve head parameters were quantified using spectral domain optical coherence tomography. Genotyping was performed using Illumina OmniExpress assays (Illumina, Fremont, CA, USA). Index single nucleotide polymorphisms (SNPs) from 10 known POAG associated loci (CAV1-CAV2, CDKN2B-AS1, SIX1-SIX6, ABCA1, TGFBR3-CDC7, 8q22, GAS7, AFAP1, GMDS, PMM2) were tested for association with VF MD at presentation, using multivariable linear regression. Furthermore, a weighted genetic risk score (GRS) was calculated for each patient, combining the effect size from the 11 index POAG SNPs, and tested for association with VF MD at presentation.
Results :
A total of 403 patients (mean age: 61.9±9.1 years) with POAG were enrolled in the study, of which 288 (71.5%) were high tension glaucoma (HTG) and 115 (28.5%) were normal tension glaucoma (NTG). A logistic regression model identified that worse VA (p<0.001), higher IOP at presentation (p<0.001), greater VCDR at baseline (p<0.001). Structurally, worse MD at presentation was associated with temporal (p=0.0004), superior (p<0.001), and inferior (p<0.001) nerve fibre layer thinning. Importantly, the PMM2 rs3785176 SNP (p=0.007, OR = 1.77per risk allele), was associated with worse VF MD at baseline. Increasing GRS was significantly associated with worse VF MD at baseline using two regression models (p=3×10-5, p=0.0002 for trend).
Conclusions :
The rs3785176 SNP (PMM2) was significantly associated with advanced VF loss at presentation in POAG patients of Chinese origin. Advanced VF MD at baseline is more significantly associated with a composite and increasing GRS. These initial findings warrant further investigation and replication in independent cohorts.
This is an abstract that was submitted for the 2016 ARVO Annual Meeting, held in Seattle, Wash., May 1-5, 2016.