Abstract
Purpose: :
To determine whether glaucoma affects functional recovery of the macula under photostress testing condition or not.
Materials and Methods: :
In this prospective study, two groups were enrolled. Twenty adults ( 8 men and 12 women; mean age: 69.9±7.32 years, ranging 55-84 years old) who had primary open angle glaucoma with established visual field defects, and age- and sex- matched 20 healthy subjects (mean age: 68.05±7.28 years) were included in the study and the control groups, respectively. They had full vision, and had no systemic disease at the time of enrollment. Only the right eyes were studied. Initially, both groups underwent to baseline threshold testing using Humphrey Perimeter (Central 24-2 SITA-FAST). While they were in front of the perimeter, underwent to photostress testing with a standart light bulb (60 W, 120 V AC, white color) located at a distance of 50 cm from the eye. Baseline foveolar threshold value and recovery time after photostress (at 1,2,4,6,8,10 minutes and at 2-minute intervals thereafter if values had not yet returned to baseline) were taken into account. Additionally, OCT testing (Stratus®) for both central macular thickness (CMT) and the retinal nevre fiber layer (RNFL) measurements were performed in the groups. Changes in the macular threshold values before and after the photostress testing (recovery time) in the groups were compared, and correlations of these changes to structural parameters were analyzed, statistically.
Results: :
There was no significant difference between groups in terms of the central macular thickness (study: 215.10±28.20 µm, control: 222.33±17.31µm; p>0,05). Thinner RNFL-average and RNFL-temporal values were observed in study group (p<0,001..and p<0,01). When compared to control group, all (100%) eyes in the study group had less foveolar threshold values (p<0,001), and longer recovery times (p< 0,001). No significant correlation existed between CMT and recovery time; but moderate correlation between RNFL and recovery time (p>0,05, p<0,01).
Conclusions: :
Glaucoma adversely affects recovery of achromatic macular sensitivity under photostress conditions. Photostress testing may used as a functional biomarker of glaucoma.
Keywords: visual fields • macula/fovea • nerve fiber layer