Influence of initial visual field sensitivity on visual field loss progression in open angle glaucoma

Abstract

Introduction. It is important to know the risk factors for visual field defect progression in order to predict the future development of glaucoma. Objective. To investigate the influence of visual field initial sensitivity on the rate of visual field progression. Methods. A minimum of five visual fields were performed using computerized perimetry (Octopus) over a mean follow- up 4-year period (48.85?17.84 months) in 64 persons (114 eyes) with primary open angle glaucoma. The rate of change of the whole central visual field and each of the seven regions of the field were measured by linear regression analysis of the mean sensitivity value versus time. Based on the slope of the regression line of visual field mean sensitivity over time the eyes were divided into two groups: the group with stable and the group with progressive visual field. The comparison of the mean sensitivity of the whole central visual field between the groups was performed using the Mann-Whitney U-test. The Spearman rang correlation coefficient and the Spearman probability p values were calculated to assess the mean sensitivity of the whole central visual field and of each visual field regions determined at the beginning of the study. Results. The initial mean sensitivity of the whole central visual field was lower in the group with progressive visual field (16.62?6.35 dB). Correlation between the initial mean sensitivity and the slope of the regression line was negative. The lowest mean sensitivity was in the group with progressive visual field in the upper temporal (13.73?7.35 dB), nasal (14.74?7.23 dB) and upper nasal (15.03?7.75 dB) regions. Conclusion. The lower mean sensitivity value of the visual field, especially in the nasal and upper nasal visual field regions, carries a greater risk for delayed progressive loss of the visual field in persons with glaucoma.Uvod. Faktori rizika za napredovanje promena u vidnom polju su vazni, kako bi se predvideo dalji razvoj glaukoma. Cilj rada. Cilj rada bio je da se utvrdi da li je jacina senzitivnosti vidnog polja na pocetku ispitivanja uticala na stepen napredovanja ostecenja vidnog polja tokom perioda klinickog pracenja. Metode rada. Tokom prosecnog vremena klinickog pracenja od cetiri godine (48,85?17,84 meseca) kod 64 osobe (114 ociju) sa glaukomom otvorenog ugla obavljeno je najmanje pet pregleda vidnog polja na kompjuterizovanom perimetru (Octopus). Nivo promene celokupnog centralnog vidnog polja i sedam regiona vidnog polja meren je analizom linearne regresije prosecne senzitivnosti u vremenu. Na osnovu pravca i velicine nagiba linije regresije prosecne senzitivnosti citavog centralnog vidnog polja u vremenu, ispitivane oci su podeljene na grupu sa stabilnim vidnim poljem i grupu sa progresivnim vidnim poljem. Poredjenje srednje senzitivnosti citavog centralnog vidnog polja medju grupama izvedeno je Man-Vitnijevim (Mann-Whitney) testom, a prosecna senzitivnost celog centralnog vidnog polja i svakog od prethodno odredjenih regiona vidnog polja na pocetku ispitivanja korelirana je pomocu Spirmanovog (Spearman) koeficijenta korelacije. Rezultati. Prosecna pocetna senzitivnost celokupnog centralnog vidnog polja bila je manja u grupi ociju sa kasnijom progresijom vidnog polja (16,62?6,35 dB). Korelacija izmedju prosecne pocetne senzitivnosti i nagiba linije regresije bila je negativna. Najniza srednja senzitivnost utvrdjena je u grupi sa progresivnim ispadima u vidnom polju u sledecim regionima: gornji temporalni (13,73?7,35 dB), nazalni (14,74?7,23 dB) i gornji nazalni (15,03?7,75 dB). Zakljucak. Manja prosecna senzitivnost vidnog polja, narocito u nazalnom i gornjem nazalnom regionu, nosi veci rizik za kasnije napredovanje gubitka vidnog polja kod osoba sa glaukomom.