Contrast sensitivity and disability glare in patients with dry eye

Abstract

. Purpose: To evaluate contrast sensitivity and disability glare in patients with dry eye using the Contrast Glaretester 1000. Methods: Contrast sensitivity and disability glare were determined in 33 eyes of 33 patients with dry eye and 30 eyes of 30 healthy control subjects for six target sizes with a visual angle of 6.3–0.7 degrees using the Contrast Glaretester 1000, whose working mechanism is similar to that of the conventional perimetry instrument. Results: Contrast sensitivity was significantly worse in dry eye group when viewing all target sizes (reduction of 0.10–0.25 log contrast units, p < 0.01) except at 6.3 degrees. In the presence of glare, differences in log contrast sensitivity between the groups (0.10–0.25 units) were significant (p < 0.01) for all target sizes, with the dry eye group showing worse results. The reduction in contrast sensitivity induced by glare (disability glare) was significantly worse in the dry eye group versus the control group but only for the 2.5‐degree size target, where 0.14 log contrast units were lost. Conclusions: Contrast sensitivity with and without glare was significantly reduced in patients with dry eye compared with control subjects, but the number of log contrast units lost with glare (disability glare) was similar in the two groups, except for the 2.5‐degree size target.

The relation of functional visual acuity measurement methodology to tear functions and ocular surface status

“…Dry eye patients with visual impairment or symptoms in everyday life are reported to have decreased contrast sensitivity which reduces their ability to appreciate subtle differences in color or shape under low light or indirect bright-light conditions [2][3][4][5]. It is also reported that irregularity of the ocular surface contributes to glare disability and that this glare disability may be reflecting visual disability in the early phase of dry eyes, such as dry eye without punctuate epithelial keratopathy [6,7].…”

“…Initial studies reported measurement of visual acuity over a 30-s interval under forced eye opening and topical anesthesia with eye drops [7][8][9][10]. It is, however, questionable whether visual acuity measured after the application of topical anesthesia actually reflects the acuity status under natural conditions.…”

“…It is believed that a regular and smooth ocular surface with a stable tear film is required to form clear visual images [6][7][8][9][10][11][12]. The surface regularity index (SRI) and surface asymmetry index (SAI) measured by corneal topography, wave front, and tear stability analyses systems have been found to be significantly worse in patients with dry eye compared with normal subjects [6,11,[13][14][15].…”

Corneal Fluorescein Staining Correlates with Visual Function in Dry Eye Patients

“…24,30 -32 Glare test may be also a useful method of reflecting visual disability. 25,26 It was reported that irregularity of the ocular surface contributes to glare disability in the early phase of dry eye disease such as in dry eyes without SPK. 25,26 Functional visual acuity (VA), which evaluates the time-wise changes in VA, can also be a helpful method of detecting the masked impairment of visual performance in dry eye patients who report decreased VA despite showing normal VA in standard VA testing.…”

“…Contrast sensitivity is considered an accurate method of measuring the quality of vision in patients with dry eye syndrome. [23][24][25][26][27][28][29] It has been reported that contrast sensitivity is decreased in dry eye patients with the impaired ability to appreciate subtle differences in color or shape under low light or indirect bright-light conditions. 24,30 -32 Glare test may be also a useful method of reflecting visual disability.…”