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RESEARCH PRODUCT

Keratoconus stage impact on visual acuity and contrast sensitivity.

subject

description

Contrast sensitivity decreases in keratoconus subjects even before the decrease is presented at high contrast visual acuity. The aim of our study was to estimate the subject’s contrast sensitivity and visual acuity in different keratoconus stages. In our study, there were included 45 keratoconus subjects (77 eyes) with the first, second and third keratoconus stages. Visual acuity and contrast sensitivity were measured at 3 m with the best possible spectacle correction and without vision correction using FrACT program 3.9.3. In the study, contrast sensitivity was measured at following spatial frequencies – 1, 3, 5, 7, 9, 11, 13 and 15 cpd. Contrast sensitivity analyse showed that there was a statistically significant difference among the contrast sensitivity of the first, second and third keratoconus stages in all spatial frequencies. If the keratoconus stage increased, the contrast sensitivity decreased more. The median visual acuity of first stage keratoconus subjects with spectacle correction was 0.56 (0.36, 0.65) decimal units, second stage keratoconus – 0.38 (0.21; 0.47) and third stage – 0.13 (0.08, 0.22).