The impact of visual field defects following anterior temporal lobectomy

Abstract

Objective: This prospective study aimed to quantify visual field defects (VFDs) along with other defects in ophthalmic functions after anterior temporal lobectomy (ATL) in patients with mesial temporal lobe epilepsy (MTLE) and their impact on quality of life using a VFQ-25 questionnaire.

Methods: Ophthalmic evaluation was done during pre-operative evaluation as well as 3 months after surgery. It included the Best Corrected Visual Acuity (BCVA), visual field evaluation, colour vision examination, fundoscopy, extraocular movements and diplopia charting. Visual field evaluation was done using a Humphrey field analyser. The foveal threshold (FT), mean deviation (MD) and pattern standard deviation (PSD) were calculated for each patient. Quality of life assessment was done using the Visual Functioning Questionnaire-25 (VFQ-25). Two-tailed independent T-tests and Chi-square tests were performed for comparison of results.

Results: Thirty-four patients were included in this study (23 men and 11 women). The mean age was 26.6 years (range 9-44 years). Post-operatively, none complained of a visual field disturbance. Thirty-one (91.17%) of 34 patients had a new quantifiable superior quadrantanopia. FT, MD and PSD of patients ranged between 29db to 40db, -1.23 to -14.28 and 1.75 to 15.34, respectively. There was no detectable abnormality in visual acuity, colour vision, fundoscopy, diplopia charting or extraocular movements. VFQ-25 scores ranged from 84 to 100. The difference between VFQ scores of patients with and without quadrantanopia was not significant.

Conclusion: Standard ATL produces asymptomatic VFDs that do not affect quality of life. A combined effort of the neurologist and ophthalmologist is recommended to counsel the patient before surgery.