Abstract
Purpose: :
To determine the frequency of perimetric examination to identify changes in the visual field (VF) of glaucoma patients
Methods: :
96 eyes of 96 primary open angle glaucoma (POAG) patients (66±15.96 years) were included with at least a 5-years VF follow-up and at least 7 VF tests during the study period (overall of 846 VF examined).The average number of VF was 8,63 ± 2,65 for each eye examined. All the VF were processed ( PERIDATA 2.3 version) to verify the trend of perimetric indexes over time.
Results: :
Results underwent a comparative analysis (T test SPSS 9 ) to determine the VF trend (db/year) over time. The trend of all the analyzed VF was compared with that obtained on half of them, excluding one VF on three in order to maintain the same time interval with half the VF analyzed. An analysis of the Mean Defect (MD) index trend over time was also carried out, dividing the sample into two groups in relation to the number of VF done in the average follow-up time (8,4 ± 2,64). The first group, "high frequency", included 39 patients with > 8 VF in the average follow-up time (average number of tests performed per patient 11.05 ± 1.91 and average interval between tests of 0.76 year) while the second group, "low frequency", included 57 patients with < 8 VF tests in the average follow-up time (average number of tests performed per patient 6,95 ± 0,60 and average interval between tests of 1,21 year ). T-test performed comparing worsening trend indexes of all the VF against half of them in the same interval of time did not show a statistic significance (p = 0,537; CI = -0,11/0,06). Trend analysis of the MD carried out on the "high frequency patients" showed some significance (p = 0,017; CI = -3,102/-0,315). In the "low frequency" group trend analysis did not show statistical significance (p = 0,080; CI = -1,679/0,097).In the same time interval, the overall number of VF tested is not significant.
Conclusions: :
A greater frequency of tests consents a predictive evaluation of developement rate of glaucoma so permitting the early establishment of a suitable therapy for each patient.
Keywords: perimetry • visual fields • clinical (human) or epidemiologic studies: biostatistics/epidemiology methodology