Evaluation of the Visual Function in Interventional Radiology Personnel

Abstract

Purpose: Ocular ionizing radiation exposure can results in progressive lens damage leading to cataract since the lens is one of the most radiosensitive tissues. This condition can causes visual impact as changes in contrast sensitivity and visual disability. The purpose of the study was to evaluate visual acuity and contrast sensitivity changes at different spatial frequencies in subjects exposed to occupational ionizing radiation.

Methods: This prospective study was approved by Ethics Committee of the Universidade Federal de São Paulo. Visual acuity and contrast sensitivity were evaluated from each eye monocularly in two groups: study group (10 subjects; mean age 45.40 ±10.75 years old) exposed to ionizing radiation from a radiology service and control group (18 subjects; mean age 42.33 ±10.31 years old) unexposed to radiation. Optec 6500P Functional Vision Analyzer was used to assess the best corrected distance visual acuity and the contrast sensitivity at five spatial frequencies (1.5, 3, 6, 12 and 18 cpd). Slit lamp image documentation of the lens and fundus photography were carried out. Mann-Whitney test was used for comparison between study and control groups.

Results: In the study group the better eye visual acuity ranged from 0.50 to -0.20 logMAR (mean: 0.07±0.21; median: 0.02 logMAR) and the worse eye visual acuity ranged from 0.62 to -0.18 logMAR (mean: 0.20±0.27; median: 0.16 logMAR). In the control group the better eye visual acuity ranged from 0.20 to -0,20 logMAR (mean: -0.06±0.09; median: -0.08 logMAR) and 0.20 to -0.20 logMAR (mean: 0.01±0.10; median: 0.00 logMAR) from the worse eye. Visual acuities were lower in the ionizing radiation exposed group from better and worse eyes compared to controls (p=0.065 and p=0.026 respectively). Spatial contrast sensitivity showed declining in the study group at higher spatial frequencies (12 and 18 cpd) in the better eye (p=0.044) and at high frequencies (12 and 18 cpd) in the worse eye (p=0.002 and p=0.020 respectively). There was not significant difference between study and control to lower spatial frequencies.

Conclusions: Visual acuity and contrast sensitivity at higher spatial frequencies were reduced in subjects exposed to occupational ionizing radiation. These preliminary findings suggest future studies with larger and age-matched samples besides different occupational radiation exposure times to find out others relationships to the visual functions.

Keywords: 478 contrast sensitivity