1. Halil Ates1, Suzan Guven Yilmaz1, Murat Erbezci2
Effects of Peripapillary Nerve Fiber Layer Thickness and Visual Field on Reading Performance in Glaucoma Patients
Halil Ates1, Suzan Guven Yilmaz1, Murat Erbezci2
1Ege University Hospital, Ophthalmology Department
2Ophthalmology, Private , Izmir, Turkey
INTRODUCTION
Glaucoma often deteriorates the quality of life by making daily activities, such as walking, driving and reading, difficult .1,2 Reading is a complex process that requires coordinated eye movement , foveal function and visual information processing within the brain, and, thus, reading ability cannot be assessed by measurement of visual acuity or visual field test alone. 3 Yet, studies on reading performance in patients with glaucoma are limited.
PURPOSE
To investigate the effects of peripapillary nerve fiber layer (RNFL) thickness and visual field (VF) on reading speed in patients with open angle glaucoma.
MATERIAL and METHOD
Thirty-eight patients (M = 15, F = 23; mean age, 64.9 ± 10.2 years) with open angle glaucoma were enrolled in this cross-sectional, comparative, non-interventional study. Patients with visual acuity less than 0.7 and who had additional ocular pathology were excluded. All patients underwent SITA-standard 24-2 Humphrey VF testing and peripapillary RNFL thickness measurement by Topcon SD-OCT. Reading performance was examined by the Turkish version of the International Reading Speed Test (IReST) (Figure-1) and were compared to that of age-matched normal subjects (n=37). Effects of RNFL thickness and VF parameters on reading speed in better eye (with least VF damage) of glaucoma group were investigated.
RESULTS
Demographic data and clinical characteristics of patients are presented in Table-1. Reading speed was significantly lower in glaucoma group when compared with the normal subjects (102.5±35.0 and 133.1±13.4 words/sec; respectively, p<0.05 by independent t-test). Mean RNFL thickness in the better eyes of glaucoma patients were 90.1±17.9 (36-126)µ and VFI, MD, PSD, progression rate of VF were 87.7±19.4, -6.1±6.5 dB, 4.5±4.7 dB, 0.7±0.9 dB/year; respectively (Table-2). There was strong positive correlation between reading speed and superior and nasal RNFL thickness values in the better eyes with glaucoma (r=0.537, r=0.360; respectively, p<0.05 by Pearson's correlation analysis). The strongest correlation between reading speed and VF parameters was observed with progression rate and VFI (r= and r=0.497; respectively, p<0.05 by Pearson's correlation analysis). This parameters were followed by MD and PSD with lower significance (r=483 and r=-0.426; respectively, p<0.05 by Pearson's correlation analysis).
Table-2. RNFL and VF Parameters of Both Eye in Study Group
Table-1. Demographic data and clinical characteristics of patients
Figure-1. Turkish version of the International Reading Speed Test (IReST)
DISCUSSION
Near vision tasks such as reading are the most valued visual function amongst subjects with glaucoma. It has been reported that subjects with bilateral glaucoma were almost 5 times more likely to report severe difficulty with near activities than subjects without glaucoma.5,6 This confirms several clinic-based studies that demonstrate more vision-related difficulty with near vision tasks in the presence of glaucoma-related VF loss. 7 In our study, the reading performance deteriorated even in glaucoma patients with preserved visual acuity. Superior and nasal RNFL thicknesses, and all VF parameters were associated with reading speed of the better eye.
REFERANCES
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