June 2020
Volume 61, Issue 7
ARVO Annual Meeting Abstract  |   June 2020
Contrast sensitivity reduction in the early stages of Keratoconus
Author Affiliations & Notes
  • Ravid Doron
    Optometry, Hadassah academic college, Jerusalem, Israel
  • Ariela Gordon-Shaag
    Optometry, Hadassah academic college, Jerusalem, Israel
  • Einat Shneor
    Optometry, Hadassah academic college, Jerusalem, Israel
  • Footnotes
    Commercial Relationships   Ravid Doron, None; Ariela Gordon-Shaag, None; Einat Shneor, None
  • Footnotes
    Support  None
Investigative Ophthalmology & Visual Science June 2020, Vol.61, 3336. doi:
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      Ravid Doron, Ariela Gordon-Shaag, Einat Shneor; Contrast sensitivity reduction in the early stages of Keratoconus . Invest. Ophthalmol. Vis. Sci. 2020;61(7):3336.

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      © ARVO (1962-2015); The Authors (2016-present)

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Purpose : Contrast sensitivity assesses visual performance and consequently evaluates functional visual impairment. Keratoconus subjects are often diagnosed at later stages of the disease when visual acuity is reduced. However, in the early stages of keratoconus, subjects are often asymptomatic and have normal visual acuity. Identification of keratoconus patients at early stags is crucial for interventions such as collagen cross-linking. This study examines if subjects with early manifestation of keratoconus and normal visual acuity show reduction in contrast sensitivity.

Methods : Healthy and keratoconus subjects with 20/20 visual acuity (ETDRS, LogMAR chart) were tested with autorefraction (L80, Luneau, France) over-refraction, corneal tomography (Sirius, CSO, Italy) and retinoscopy and slit lamp bio-microscopy for clinical signs of keratoconus. Contrast sensitivity with various frequencies (6,9,12 cycle per degree; cpd) was tested using computerized psychophysical tests. Gabor patches stimuli were presented on a Philips color monitor (1024 X 768 pixels at a 100 Hz refresh rate) with two alternatives forced-choice method. Contrast sensitivity was compared using the Mann-Whitney test.

Results : Thirty healthy subjects (range of age 17-38 years, 30 eyes) with visual acuity of 0.00±0.00 LogMar and ten keratoconus subjects (range of age 17-30 years, 10 eyes) with visual acuity of 0.002±0.006 LogMar (U=120, p=0.08) participated in the study. Contrast sensitivity (100/ contrast-threshold) was significantly different between keratoconus subjects and healthy subjects for 6 cpd (keratoconus: 8.76±7.89, control: 18.45±10.04, U=68.5, p=0.009), 9 cpd (keratoconus: 4.56±4.31, control: 7.89±3.72, U=81.0, p=0.031) and 12 cpd (keratoconus: 2.23±1.94, control: 3.69±2.29, U=80.5, p=0.028).

Conclusions : Psychophysical measurements show differences in contrast sensitivity between keratoconus vs. normal subjects although both have good and similar visual acuity. These differences may represent structural changes that occur in the early stages of the keratoconus.

This is a 2020 ARVO Annual Meeting abstract.


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