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RESEARCH STUDY

RESEARCH

Effect of Uncorrected Astigmatism on Vision

AUTHOR:

James S. Wolffsohn, PhD, Gurpreet Bhogal, BSc and Sunil Shah, MD

SPONSOR/INSTITUTION:

Alcon

YEAR PUBLISHED:

2010

PUBLICATION:

JAMA Ophthalmology

KEY HIGHLIGHTS:

PURPOSE: To examine the effect of uncorrected astigmatism in older adults.

SETTING: University Vision Clinic


METHOD: Twenty-one healthy presbyopes, aged 58.9±2.8 years, had astigmatism of 0.0 to -4.0 x 90DC and -3.0DC of cylinder at 90, 180 and 45 induced with spectacle lenses, with the mean spherical equivalent compensated to plano, in random order. Visual acuity was assessed binocularly using a computerised test chart at 95%, 50% and 10% contrast. Near acuity and reading speed were measured using standardised reading texts. Light scatter was quantified with the cQuant and driving reaction times with a computer simulator. Finally visual clarity of a mobile phone and computer screen was subjectively rated.


RESULTS: Distance visual acuity decreased with increasing uncorrected astigmatic power (F=174.50, p<0.001) and was reduced at lower contrasts (F=170.77, p<0.001). Near visual acuity and reading speed also decreased with increasing uncorrected astigmatism power (p<0.001). Light scatter was not significantly affected by uncorrected astigmatism (p>0.05), but the reliability and variability of measurements decreased with increasing uncorrected astigmatic power (p<0.05). Driving simulator performance was also unaffected by uncorrected astigmatism  (p>0.05), but subjective rating of clarity decreased with increasing uncorrected astigmatic power (p<0.001). Uncorrected astigmatism at 45 or 180 orientation resulted in a worse distance and near visual acuity, and subjective rated clarity than 90 orientation (p<0.05).


CONCLUSION: Uncorrected astigmatism, even as low as 1.0DC, causes a significant burden on a patient’s vision. If left uncorrected, this could impact significantly on their independence, quality of life and wellbeing.


Link: http://eprints.aston.ac.uk/16675/1/Effect_of_Uncorrected_Astigmatism_on_Vision.pdf