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Vladimir Yevseyenkov, Preeti Bhukhan, Ariba Bhuvad, Anna Moore; Comparison of Novel Automated Objective Contrast Sensitivity Measurement Using iTrace Aberrometer vs. Standard Subjective Contrast Sensitivity Methods in Patients with Dry ARMD. Invest. Ophthalmol. Vis. Sci. 2012;53(14):4381.
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© ARVO (1962-2015); The Authors (2016-present)
Contrast sensitivity has become a vital tool in the assessment of functional vision. Standard contrast sensitivity measurement tests (such as the MARS chart, Vector Vision CSV-1000E or Pelli-Robson chart) utilize only subjective measurements and can be time consuming to perform. This study is an attempt to validate a new method of contrast sensitivity testing that is fast, reliable and objective. The iTrace contrast sensitivity measurements (objective) obtained will be compared with the results of two standard contrast sensitivity tests, the Vector Vision CSV-1000E system and the MARS chart in patients diagnosed with dry ARMD.
Twelve patients (n=23 eyes) with dry ARMD (mean age = 77.2 ± 6 yrs; range 65-84), were recruited for this study. Their BCVA ranged from 20/40 to 20/500 Snellen equivalent monocularly. Each patient was then tested without refractive correction on the iTrace ray tracing wavefront aberrometer and corneal topographer. Each measurement was repeated 3 times. Subjective tests were performedwith habitual correction in place using the Vector Vision CSV1000E at mean luminance of 85 cd/m2 at 5 feet. MARS chart testing was conducted at a mean luminance of 85 cd/m2 at 40 cm.
All subjective data was converted to contrast sensitivity logMAR scores based on a standardized chart. Test-retest reliability of objective data as measured by iTrace was determined using Cronbach’s alpha analysis. All statistical measurements for point spread function (PSF), modulation transfer function (MTF), and root mean square (RMS) were above 0.9. Contrast sensitivity measurements from the subjective tests, (MARS and Vector Vision ranged from 0.4 logARr to 1.2 logMAR. Averages include a PSF of 0.295an MTF average of 0.421 and and RMS average of 2.60.
Patients with dry ARMD exhibited reduced visual acuity and contrast sensitivity measurements via both standard subjective tests, which is consistent with previously reported literature. Objective indirect measurements as measured by novel automated objective contrast sensitivity measurement with the iTrace aberrometer were reduced. This is consistent with the statistical analysis showing a reduction in contrast sensitivity PSF, MTF, and RMS values. Our results support that the iTrace could provide valuable objective measurements such as PSF, MTR, and RMS that could in part be utilized as a predictors of contrast sensitivity as well as functional vision loss in dry ARMD patients.
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