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K. H. Baratz, J. W. McLaren, L. J. Maguire, K. M. Kittleson, S. V. Patel; Light Scatter, Visual Acuity, and Contrast Sensitivity After Descemet Stripping With Endothelial Keratoplasty. Invest. Ophthalmol. Vis. Sci. 2008;49(13):1148.
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© ARVO (1962-2015); The Authors (2016-present)
To evaluate backscattered light from the cornea, visual acuity, and contrast sensitivity after Descemet stripping with endothelial keratoplasty (DSEK).
In a prospective, non-randomized study, 21 eyes of 19 participants, all with corneal edema from Fuchs dystrophy, were evaluated before surgery (n=21) and at 1 (n=19), 3 (n=17) and 6 (n=10) months after microkeratome-assisted DSEK. At each visit, backscattered light was determined from the intensity of a slit beam image through the cornea. Best spectacle corrected visual acuity (BSCVA) was measured by using an automated ETDRS testing protocol. Contrast sensitivity at 1.5, 3, 6, 12 and 18 cycles/degree was evaluated by using the Functional Acuity Contrast Test (Vision Sciences Research Corp., San Ramon, CA). Measurements were compared with the same measurements in 41 normal eyes of 41 subjects by using generalized estimating equation models with Bonferroni adjustment.
Mean BSCVA was 0.46 ± 0.24 logMAR (Snellen equivalent: 20/58) before surgery, 0.31 ± 0.22 (Snellen equivalent: 20/41; p=0.06) at 3 months, and 0.27 ± 0.14 (Snellen equivalent: 20/37; p=0.02) at 6 months. Before surgery, backscattered light was 69%, 55% and 115% higher than normal in the anterior, middle, and posterior corneal thirds, respectively. Backscatter decreased after surgery, but at 6 months remained 22% higher than normal in the middle (p<0.001) and 30% higher in the posterior (p<0.001) thirds, but not significantly different in the anterior third (3%; p=0.8). Compared with before surgery, only contrast sensitivity at 3 cycles/degree was improved at 6 months (p<0.001). The log of contrast sensitivity at 1.5, 3 and 6 cycles/degree remained at 1.57, 1.61 and 1.05 respectively, significantly lower than normal (1.71, 1.85, and 1.74 respectively; p≤0.05) through 6 months. At each visit, contrast sensitivity at 12 and 18 cycles/degree was not measurable in the DSEK eyes.
Backscattered light from the cornea decreases after DSEK, yet remains higher than normal in the posterior two-thirds of the cornea, the region that includes the interface, through 6 months. Similarly, contrast sensitivity improves but remains lower than normal at all spatial frequencies tested.
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