Are orthoptic measures robust during exposure to unpleasant environmental noise?

Abstract

Aim: Orthoptic clinics are sometimes noisy and sometimes quiet. This study experimentally tested how this noise might affect some orthoptic measures. The experiment looked for changes in measurements of visual acuity (VA), RAF rule and autorefraction during exposure to unpleasant environmental noise. Methods: In a counterbalanced repeated measures experiment 12 participants aged between 19 and 24 years, with normal vision, had their VA, RAF rule accommodation and accommodation to targets at three distances measured (0.33, 3 and 6 m). These were measured in two sessions, each lasting about 15 minutes, conducted on separate days. One session involved exposure to a recording of continuous loud unpleasant noise; the other, control session was conducted in a quiet environment. Within each session the measures above were made twice: at the start and end of each session. Participants also commented on their experience of each session. Results: Although the majority of participants found the noisy environment unpleasant, the environmental noise produced no significant effects on VA, time to perform VA, RAF rule and accommodation, or variation in accommodation to targets. Conclusion: The tests used here appear robust to the effects of unpleasant environmental noise when used on adult participants with normal vision. Possible reasons for this are discussed. It remains to be tested whether such noise might affect either those who have compromised vision or children, who may require more effort to perform these tests.

Keywords

• Accommodation
• Noise
• RAF rule
• Visual acuity