Bilateral Field Loss Research Articles

The Low-pressure Glaucoma Treatment Study (LoGTS): Study design and baseline characteristics of enrolled patients

The Low-Pressure Glaucoma Treatment Study (LoGTS) seeks to evaluate visual field stability in low-pressure glaucoma patients randomized to intraocular pressure reduction in both eyes with topical twice daily brimonidine tartrate 0.2% versus twice daily timolol maleate 0.5%. This article describes the LoGTS design and presents baseline characteristics of the subjects.Randomized, multicenter, double-masked clinical trial.Low-pressure glaucoma patients 30 years of age or older were identified. Exclusion criteria included an untreated pressure of more than 21 mmHg, advanced visual field loss, and contraindications to study medications.Randomization of both eyes to double-masked monotherapy with brimonidine or timolol. Follow-up visits included Humphrey 24-2 full-threshold perimetry, tonometry every 4 months, and annual optic disc photography.Progression of visual field loss.One hundred ninety patients were randomized between 1998 and 2000. Mean age (+/-standard deviation) was 64.9+/-10.7 years. Women comprised 59.5% of the patients. Fifty-three patients (27.9%) had unilateral field loss. The 137 patients with bilateral field loss were older than those with unilateral field loss: 65.7 versus 62.3 years of age (P<0.05). Mean untreated diurnal intraocular pressures were similar between the eyes of the bilateral patients (mean, 15.5 mmHg in both eyes) and unilateral patients (mean, 16.0 mmHg in field loss vs. 15.6 mmHg in fellow eyes). Visual field mean deviation for all eyes was -5.4+/-4.7 decibels. Central corneal thickness in 168 phakic patients was 543 +/- 35 microm (range, 435-655 microm); thickness was less than 500 microm in 15 eyes and was more than 600 microm in 11 eyes. Mean vertical cup-to-disc ratio for all eyes was 0.67+/-0.15. Unilateral field loss patients had a larger cup-to-disc ratio in the field loss eye (0.75+/-0.12) than the fellow eye with a normal field (0.60+/-0.17, P<0.0001). Disc hemorrhage was present at baseline in 29 patients (32 eyes).The LoGTS was successfully able to recruit and enroll patients with open-angle glaucoma and statistically normal intraocular pressure into a longitudinal, prospective clinical trial comparing 2 different glaucoma medications. Baseline characteristics of note were a preponderance of females, unilateral field loss in 27.9% of participants, and frequent optic disc hemorrhage. Central corneal thickness had a normal distribution and did not account for false low-pressure measurements in LoGTS patients.

Frequency of asymmetric visual field defects in normal-tension and high-tension glaucoma

Objective The purpose of the study was to evaluate the frequency of asymmetric visual field loss at presentation in patients with normal-tension glaucoma (NTG) and high-tension glaucoma (HTG). Design A retrospective cross-sectional study design was used. Participants Four hundred and three NTG patients and 337 consecutive HTG patients (consecutive diagnoses between 1986 and 1996). Intervention Analysis of the frequency of unilateral field loss presentations in NTG and HTG. The visual fields of fellow eyes were compared to determine the side of more severe field loss. For the NTG patients, the relationship between the side with greater field loss and corresponding intraocular pressure (IOP) was investigated. Main outcome measures Humphrey field analyzer mean defect (MD) and mean diurnal IOP. Results In the NTG group, 101 (25%) patients presented with unilateral field loss. The proportion of cases with unilateral field loss decreased with increasing age of presentation (chi-square test for trend = 26.9; P < 0.0001). Sixty-four percent of the patients had unilateral field loss in the left eye. Sixty-eight percent of the cases with bilateral field loss had a higher MD in the left eye. The diurnal IOP was estimated as 0.23 ± 0.068 mmHg (mean ± SE) higher in the left eye ( P = 0.001). In the HTG group, 104 (31%) patients presented with unilateral field loss. The proportion of cases with unilateral field loss decreased with increasing age of presentation (chi-square test for trend = 4.6; P = 0.03). Right and left eyes had an equal chance of having field loss in unilateral cases and of being the side of more advanced field damage in bilateral cases. Conclusions The frequency of cases with unilateral field loss was similar in HTG and NTG patients. Patients with unilateral field loss at presentation were more likely to be at the younger end of the age range. In the NTG population we studied, the left eye was more frequently the side of onset of field loss and 2.1 times more likely to present with a greater field defect than the right eye. In HTG patients, right and left eyes showed an equal chance of being the side of onset of field damage and the more affected side.

Visual deficits in alexia without agraphia

Objectives: Most patients with alexia without agraphia (AWOA) have a right homonymous hemianopsia, but some have partial right homonymous field loss and a few have normal visual fields. This reported variability of visual deficits prompted the present study which more precisely delineates visual function in AWOA. Materials and methods: Nine patients with AWOA underwent neuro-ophthalmologic examination including Goldmann perimetry. Results: Three patients had complete right homonymous hemianopsia, two had complete right homonymous hemianopsia with additional binocular or monocular left field loss, two had right superior quadrantanopsia, and two had bilateral superior or inferior quadrantanopsia. Right superior quadrant vision was impaired in eight patients and no patient demonstrated an isolated right inferior quadrantanopsia or an isolated left homonymous field defect. No patient attained 20/20 visual acuity OU. Cerebrovascular disease was the most frequent etiology of AWOA (six patients), and eight patients had bihemispheric disease. Conclusions: This study demonstrates that bilateral visual field loss and decreased visual acuity occur in many cases of AWOA. The frequent presence of right superior quadrantic field defects implies a critical role in reading for the ventral outflow pathways of the dominant calcarine cortex. Although right hemianopsia and a lesion involving left occipital lobe and splenium remain the paradigm for AWOA, bilateral field loss, decreased visual acuity, and bihemispheric disease are common in AWOA and may adversely affect the integrity of neural reading mechanisms.