Endophenotypic Analysis of Glaucoma Patients Who Present With Paracentral Visual Field Loss

Abstract

Abstract: : Purpose: To compare the demographic and ocular features in glaucoma patients with incident paracentral versus nasal step visual field loss. Methods: We reviewed all Glaucoma Service charts at Massachusetts Eye and Ear Infirmary to identify patients with new–onset, isolated paracentral or nasal step defects on the pattern deviation (PD) plot of a reliable SITA standard Humphrey 24–2 visual field (VF) secondary to glaucoma. All patients had a subsequent VF confirming loss exhibited on the index VF. No exclusion criteria for the type of glaucoma was employed. We collected information regarding the demographic and ocular characteristics of both groups. We defined disease progression as the development of a reproducible defect in a new VF sector. We excluded patients with known non–glaucomatous optic neuropathy, macula pathology that could explain paracentral VF loss or diabetic retinopathy requiring laser treatment. Results: We identified 18 patients with incident paracentral visual field loss (iPC loss group) and randomly selected another 18 patients with incident nasal step loss (iNS loss group) who met criteria for this study. There were no significant demographic differences (age, gender and race) between the groups. Most patients in both groups had open–angle glaucomas (OAG) and there was a nonsignificant trend (p=0.20) toward lower maximum intraocular pressure prior to the index VF in the iPC loss group (16.4 ± 3.9 mm Hg) versus the iNS loss group (18.8 ± 6.6 mm Hg). Yet, the mean sensitivity of the abnormal cluster in the paracentral zone of the PD plot in the iPC loss group was worse than the corresponding value for the nasal step zone in the iNS loss group (–15.5 ± 6.9 dB vs. –9.4 ± 5.8 dB, p=0.007). Furthermore the point with lowest sensitivity in the paracentral zone of the PD plot was more depressed in the iPC loss group than the corresponding point in the nasal step zone of the iNS loss group ( –24.5 ± 11.0 dB vs. –14.8 ± 7.1 dB, p=0.004). Finally, while mean follow–up time was similar for both groups, (5 years for the iPC loss group and 4 years for the iNS loss group, p = .16), 50% of patients in the iPC loss group had disease progression compared to 11% of patients in the iNS loss group (p=0.01). Conclusions: This data suggests that patients who present with paracentral visual field defects exhibit denser scotomas at onset and show more VF progression than patients who present with nasal step defects. Larger studies are indicated to verify these findings and further delineate the endophenotype associated with incident paracentral visual field loss from OAG.

Keywords: visual fields