Effect of blink suppression in critical cases of evaporative dry eye on visual quality

Objective: To study the effect of blink suppression on visual quality in critical cases of evaporative dry eye.

METHODS: Whole eye high-order aberrations (HOA) were continuously measured in 10 eyes with a short tear time (TBUT; 3.0 ± 0.6 seconds) for 30 seconds without ocular surface staining and tears were not deficient. During the measurement, subjects were asked to blink once every 10 seconds, more than twice the TBUT. Analyze aberration data, including quasi-like aberrations, spherical aberrations, and total HOA, up to the sixth order of the Zernike polynomial.

RESULTS: The continuous change in total HOA in subjects with shorter TBUTs was in a sawtooth pattern, with a clear upward curve that increased after blinking. After 5-9 seconds of blinking, total HOA was significantly higher than immediately after blinking (P < 0.001).

CONCLUSIONS: Subjects with short TBUTs that suppress blinking may reduce visual quality, such as when the gaze is on the video display terminal, even if there is sufficient tear fluid. Key words: tear film rupture dry eye wavefront examination

Dry eye can be classified as lack of watery liquid dry eye and evaporative dry eye. 1 In cases of mildly evaporative dry eye, the amount of tear fluid is not always reduced, and only the shortening of the tear film rupture time (TBUT) can account for tear abnormalities. 2 There are many critical cases in clinical practice. Between evaporative dry eyes and healthy eyes, it is found that TBUT is shortened and symptoms of dry eye appear. However, the ocular surface is not damaged and tears are not insufficient. 3 In TBUT shortened eyes, the tear film may begin to rupture rapidly during the next blink of the eye at the next instant, despite the fact that the eye surface has sufficient tears; this may produce dry eye symptoms with blurred vision, eye fatigue, and discomfort.

To quantify the effect of reducing the TBUT shortening on dynamic visual quality after blinking, high-order aberrations (HOAs) were continuously measured on TBUT-shortened subjects during a 10-second blink interval that exceeded twice the TBUT.