Vessel Caliber in Normal Tension and Primary Open Angle Glaucoma Eyes With Hemifield Damage.

PURPOSE OF THE STUDY: The purpose of the study was to evaluate retinal vessel diameter in age-matched normal tension glaucoma (NTG) and primary open angle glaucoma (POAG) eyes with hemifield involvement. METHODS: Fundus photographs of patients with hemifield defect, good visibility of retinal nerve fiber layer defect, and vessels were compared with 30 controls. One eye of each patient (28 NTG and 30 POAG) was randomly chosen for analysis using Image J software by different clinicians at 2 levels. The structural parameters analyzed included retinal nerve fiber layer defect width, diameter of vessels (superotemporal or inferotemporal artery and superotemporal or inferotemporal vein). RESULTS: The average superotemporal artery diameter was similar in NTG (71±16.8 µm), POAG (79±26.6 µm), and controls (82±14.1 µm), P=0.2 with similar pattern seen for other vessels. The affected quadrant in all eyes and those with disc hemorrhage (n=8) did not have significantly different arteries and veins diameter as compared with the unaffected quadrant in that eye. No relation of artery or vein diameter with retinal nerve fiber layer defect width or clinical variables in NTG or POAG eyes was seen on multivariate regression analysis. CONCLUSIONS: The vessel diameter was not significantly different in the affected and unaffected quadrants of age and severity-matched NTG and POAG eyes with hemifield structural and functional defect as reported in earlier studies. These results point toward the possibility that vascular diameter changes may not be the cause for glaucomatous changes.

Central Field Index Versus Visual Field Index for Central Visual Function in Stable Glaucoma.

OBJECTIVE: To compare the variability of central field index (CFI) versus visual field index (VFI) in stable glaucoma with central fixation involvement. MATERIALS AND METHODS: For this retrospective study, we identified multiple visual fields (VFs) of patients with repeatable central fixation involvement on Humphrey VFs (24-2 and 10-2 program) which were stable (clinically and on VFs) over a very short period of 2 to 3 months. The VFI and CFI were calculated as described in earlier reports. We graded the fields as early [mean deviation (MD)>-6 dB], moderate (-6.1 to -12 dB), and severe glaucoma (<-12 dB) based on MD on 24-2 program. The variability of CFI and VFI between visits and across different severity of glaucoma was compared. Relation of the divergence to field indices and clinical parameters were assessed. RESULTS: The intervisit difference for VFI was greater than CFI ranging from -4% to 9% versus -1% to 8% in early (P=0.9), -13% to 18% versus -6% to 17% (P=0.056) in moderate, and -21% to 19% versus -9% to 9% (P<0.001) in severe glaucoma. The CFI within each group had narrower range than VFI with maximum range in severe glaucoma (33% to 95%). The divergence of CFI from VFI started at MD 24-2 beyond (worse) -10 dB. This difference between CFI and VFI was associated significantly with number of points with P<1% on 24-2 (R=80.3%). CONCLUSIONS: CFI is less variable than VFI in stable eyes with fixation involvement especially in severe glaucoma indicating need for incorporating CFI calculation for monitoring advanced disease in eyes with central defects.