Purchase this article with an account.
Jorgen Gustafsson, Robert Rosen, Maria Brodin, Linda Lundstrom, Peter Unsbo; Improved Refraction of Patients with Central Visual Field Loss by the Use of Low Contrast Optotypes. Invest. Ophthalmol. Vis. Sci. 2011;52(14):1899.
Download citation file:
© ARVO (1962-2015); The Authors (2016-present)
People with central visual field loss (CFL) utilize their peripheral vision for all tasks. Their refractive error can differ significantly from that of their previous foveal vision, primarily due to oblique astigmatism, when using eccentric viewing in a preferred retinal locus (PRL). Peripheral refraction for CFL patients, if done at all, is normally performed using subjective refraction with high contrast optotypes. In a previous study, we found that the peripheral resolution of normally sighted persons was affected by defocus when using low contrast optotypes, but not high contrast optotypes (Rosén et al. acc. for IOVS sept 2010, doi: 10.1167/iovs.10-5623). This study investigates the potential benefits of using low contrast optotypes for refraction of CFL patients in a clinical setting.
Patients were recruited at a local low vision clinic and refracted by experienced low vision optometrists. The inclusion criteria was CFL in both eyes and a best corrected high contrast visual acuity of logMAR 1.0 or worse. For every patient, two separate refractions were performed by using high and low contrast optotypes (100% and 25% respectively); high contrast refractive correction (HCR) followed by low contrast refractive correction (LCR). Then both high and low contrast visual acuity (HC-VA and LC-VA) were evaluated with both of the found corrections, i.e. a total of four acuity measurements were performed.
The refraction results are summarized in the table for the patients together with the improvements in HC-VA and LC-VA using LCR compared to HCR. Improvement in LC-VA was found for all patients when using LCR, except for one person, who nevertheless had a subjective preference for LCR.
In this first pilot study the results show that subjective refraction using low contrast optoptypes can be useful to find a more optimal correction for CFL patients.
This PDF is available to Subscribers Only