The Influence of Pterygium on Meibomian Glands and Dry Eye Parameters

imageSIGNIFICANCE

Mechanical factors are also associated with meibomian gland dysregulation in patients with pterygium. Dry eye parameters were assessed, and the results support the association between pterygium and dry eye disease.

PURPOSE

This study aimed to investigate how meibomian gland dysfunction and dry eye parameters relate to the existence of pterygium.

METHODS

Patients with pterygium and healthy volunteers of similar age and demographic characteristics were included. Schirmer 1 test, Ocular Surface Disease Index score, fluorescein tear film breakup time, and ocular surface staining scores (Oxford score) were recorded. Meiboscores were estimated based on meibomian gland loss rate on infrared meibography (SL-D701; Topcon, IJssel, the Netherlands). The symmetry of meibomian gland loss with respect to eyelid midline was assessed.

RESULTS

Fifty-four eyes with pterygium (group 1) and 50 eyes of healthy volunteers (group 2) were included. The mean ages were 54.0 ± 12.3 and 52.3 ± 8.0 years, respectively. Schirmer 1 test results and tear film breakup time were lower in group 1 (P = .007, P

Effect of Cognitive Mental Load on Attended and Nonattended Visual Stimuli

imageSIGNIFICANCE

In the real word, visual tasks may be concurrent with other activity that imposes mental load. Although the brain’s capacity to process information is limited, attention can improve visual performance by selectively allocating processing resources. Therefore, measuring visual performance under such circumstances can reflect patients’ vision more accurately.

PURPOSE

The aim of this study was to evaluate the effect of nonvisual task-induced mental load on visual performance at both attended and unattended locations in stimulus-driven captured attention.

METHODS

Visual function was measured with an orientation discrimination task for Gabor patches with contrasts of 10, 15, 30, 50, and 80%. Three attentional conditions (valid-cue, invalid-cue, and neutral-cue) were randomly interleaved within runs. To modulate mental load, the visual task was performed either with or without a simultaneous auditory n-back task (two-back for maximum mental load and zero-back to control for the effect of having to perform a simultaneous task).

RESULTS

Our result showed that the effect of mental load on correct responses was significant (P = .02). Correct responses decreased significantly during the two-back task when compared with the baseline condition (P = .03), but there was no significant difference between baseline and zero-back conditions (P = .06). The effect of attention and spatial frequencies on the percentage of correct responses was significant (P .05).

CONCLUSIONS

Mental load had a similar decreasing effect on attended and unattended visual stimuli. This may be due to a generalized effect on processing resources upstream to where spatial attention is allocated.