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Hui Wang, Luis A Lesmes, Michael Dorr, Zhong-Lin Lu, Tobias Elze, Peter Bex; Characterizing monocular and binocular contrast sensitivity in corrected and uncorrected myopia.. Invest. Ophthalmol. Vis. Sci. 2016;57(12):5515.
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© ARVO (1962-2015); The Authors (2016-present)
The contrast sensitivity function (CSF) provides an important measure of functional vision. Previous research  has examined how uncorrected refractive error affects vision at the lower (Pelli-Robson) and higher (Snellen acuity) ranges of spatial frequencies. The purpose of this study was to evaluate monocular and binocular contrast sensitivity (CS) across a broader range of spatial frequencies, in corrected and uncorrected myopia.
For emmetropes (n=38), three CSFs were collected in monocular (M) and binocular (B) conditions. For myopes (n=63), six CSFs were collected in two M and one B conditions, with and without optical correction. For each observer, the full set of CSFs was collected in only 15-30 min using the quick CSF at a near-to-intermediate viewing distance of 60 cm (1, 3). To compare with previous research, we calculated three contrast sensitivity metrics: (i) low-frequency CS (1 cpd); (ii) AULCSF - area under the log CSF - and (iii) CS acuity the cutoff-frequency at which sensitivity= 0.0. For myopes, analyses of CSF metrics were stratified by self-reported refractive error, ranging between -1.0D and < -6D, respectively. We evaluated test-retest repeatability, and advantage provided by M relative to B vision.
For M vision, there were significant correlations between uncorrected refractive error and both AULCSF and CSF acuity (r=-.68, p<.0001; and r=-.69, p<.0001). In Figure 1, each plot presents patterns of corrected and uncorrected contrast sensitivity in M and B conditions, as a function of refractive error. Relative to low-frequency CS or high-frequency acuity, the AULCSF exhibits the largest dynamic range (1.5 decimal log units) and the steepest decline in visual performance with an increase in uncorrected refractive error. The binocular advantage - the AULCSF difference between B and better M conditions- was the same with and without correction: ~20-.25 log units. Finally, coefficients of reliability (COR) -- ranging from .19-.24 decimal log units – were similar across conditions with and without correction.
CSF testing in mid-range spatial frequencies (and beyond) delivers a comprehensive assessment of visual performance, which is sensitive to the benefits of refraction. This study demonstrates the potential for the CSF to provide a sensitive and precise outcome measure for refractive interventions.
This is an abstract that was submitted for the 2016 ARVO Annual Meeting, held in Seattle, Wash., May 1-5, 2016.
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