Abstract
Purpose: :
To quantitatively measure the corneal sensitivity in the early post-operative period after Descemet stripping and automated endothelial keratoplasty (DSAEK) and compare it to the fellow eye.
Methods: :
Corneal sensation was tested in patients who underwent small incision, clear corneal DSAEK for either Fuchs dystrophy or pseudophakic bullous keratopathy (PBK). Patients were excluded from the study if they had a history of penetrating keratoplasty in either eye, or a failed DSAEK in the operative eye. Sensitivity was tested within the first six months using a Cochet-Bonnet aesthesiometer. The threshold sensation was measured at nine points in the four quadrants of the cornea on either side of the donor/host margin of the lenticule as well as centrally. The fellow eye served as a control. Filament length was shortened in 5 mm increments until threshold sensation was detected. A single examiner tested sensation for all patients (RLK).
Results: :
Fifty-eight eyes of 29 patients were included in the analysis. There were 8 men and 21 women. Thirteen eyes underwent simple DSAEK for PBK following clear corneal cataract surgery. Two patients underwent simple DSAEK after combined glaucoma/cataract surgery, and one patient had prior extracapsular cataract extraction. Thirteen eyes underwent combined DSAEK and phacoemulsification cataract surgery for Fuchs endothelial dystrophy. Six patients had diabetes mellitus. There was no statistical difference between all individual locations tested in the operative and control eyes (p>0.05 for all points) except for the temporal point where the main surgical incision was located (average difference: 5.52 mm, p<0.0001). The sensitivity of the temporal location was also statistically different from all other points tested within the same operative eye (all p<0.01). Comparing the average corneal sensitivity in the operative eye to the control yielded a net difference of 2.13 mm (standard deviation (SD): 3.14) which was statistically significant using the paired samples t-test (p=0.001). This difference seemed to be driven by the temporal incisional point, as noted above.
Conclusions: :
With the exception of the temporal cornea, corneal sensation remains similar to controls for small incision DSAEK. Localized decrease in sensation may be related to severing of corneal nerves with the 4.2 mm DSAEK temporal corneal incision or prior clear corneal incision. The small magnitude of the difference in sensation even at this location is statistically significant, but may not be clinically significant.
Keywords: cornea: clinical science • cornea: endothelium