Visual acuity loss in open‐angle glaucoma patients: causes and risk factor

Abstract

Purpose To identify causes of visual acuity loss in open angle‐glaucoma (OAG) patients and to determine associated risk factors. Methods From the visual field database of the University Medical Center Groningen, 400 patients with at least 3 reliable visual fields were randomly selected. Of these, 233 had OAG. OAG patients with a visual acuity of 0.5 or less in at least one eye were considered as cases; controls had to have a visual acuity above 0.5 in both eyes. Causes of visual acuity loss were determined from the medical records. Potential risk factors for visual acuity loss in OAG (age, gender, myopia, baseline IOP, corneal thickness, and visual field mean deviation [MD]) were assessed by comparing cases with acuity loss due to OAG with the controls, using logistic regression. Results Of the 233 patients with OAG, 134 (57%) were cases and 99 (43%) controls. Concerning the cases, visual acuity loss was caused by OAG in 40%, cataract 17%, AMD 14%, vitreo‐retinal surgery 10%, corneal pathology 4.5%, acquired retinal disorders 10%, and neuro‐ophthalmological disorders 4.5%. Among the assessed risk factors, cases had a lower MD (OR=0.90; P<0.001) and a higher age (OR=1.05; P=0.015). Conclusion Visual acuity loss in OAG is common but mostly due to other eye co‐morbidities. A lower MD and an older age were highly significant risk factors.

Non-Glaucomatous Causes of Decreased Vision in Glaucoma

“…In a study by N Ayachoua, 17% of cases of decreased vision were due to cataract. 3 In another report it was 50.4%. 14 Cataract is a common cause of decreased visual equity in the elderly and it is a common reversible cause of decreased visual acuity in glaucoma patients.…”

“…11 A study by N Ayachoua had reported visual loss with glaucomatous optic atrophy in 40% of patients. 3 In Africa, up to 70% of glaucoma patients presented with advanced glaucomatous optic atrophy in better eye. 12 The frequency of glaucomatous optic atrophy was higher in our patients in comparison to other studies.…”

“…12 The frequency of glaucomatous optic atrophy was higher in our patients in comparison to other studies. 3,11 We included glaucoma patients with different etiologies, and the duration of the disease varied from recently diagnosed to 20 years. Initially, there is peripheral visual loss among glaucoma patients and central vision is preserved until the advanced stage of the disease.…”

“…Keeping the population size 1,000,000, confidence interval of 95%, the margin of error 5%, and hypothesized frequency p (40) for cataract as the cause of decreased vision. 3 Patients were registered through non-probability consecutive sampling technique from an outpatient department of Abbasi Shaheed Hospital, which is a tertiary care facility. Verbal informed consent was taken from every patient.…”

“…It has been reported that decreased visual acuity among glaucoma patients might not be due to glaucoma itself. 3 It could be caused by cataract, age-related macular degeneration (ARMD), vitreoretinal surgeries, retinal disorders, corneal pathologies and neuro-ophthalmological disorders.…”