Abstract
Purpose: :
To identify any difference in contrast sensitivity function following 2 different types of corneal transplant procedures, Descemet stripping endothelial keratoplasty and penetrating keratoplasty. The most common measure used to test visual function, visual acuity tests, use high contrast characters and may not reflect typical visual tasks as well as contrast sensitivity tests.
Methods: :
The study was performed in an ophthalmology clinic that adjoins a university hospital. The 23 patients enrolled during routine follow-up appointments had undergone either Descemet stripping endothelial keratoplasty (14) or penetrating keratoplasty (9) between 2004 and 2008 and now had stable visual acuities. The indication for surgery in each of these patients had been Fuch's endothelial dystrophy or bullous keratopathy. No patient was enrolled if any other reason was present for contrast sensitivity disturbance (amblyopia, glaucoma, other optic nerve disease, macular disease, other retinal disease, severe dry eye, cataract, or others). The surgeries were all performed by one of the two cornea specialists within the department. Best corrected visual acuities were obtained in each patient. Each patient then underwent contrast sensitivity testing with each eye using the Pelli-Robson chart. The test was performed at 1 meter with a +0.75 D add used. Photopic conditions were implored (98 ft-candles in the room used).
Results: :
As expected, as logMAR decreased, log(contrast sensitivity) increased (p < 0.001). Looking at logMAR as a covariate, DSEK vs PKP as the independent variable, and log(contrast sensitivity as the dependent variable), the results suggest that there is a relationship between transplant type and log(contrast sensitivity), but are not statistically significant (p = 0.253)
Conclusions: :
Our study, at a single academic institution, with patients who had undergone DSEK or PKP within the past 4 years (and were willing to participate and who were not excluded) confirmed the relationship between visual acuity and contrast sensitivity. It also suggested, but was not statistically significant, that DSEK patients of the same acuity (as PKP patients) had better contrast sensitivity.
Keywords: contrast sensitivity • cornea: clinical science • clinical (human) or epidemiologic studies: outcomes/complications