Quality of vision following clinically successful penetrating keratoplasty☆

Abstract 

Purpose: To evaluate visual function following clinically successful penetrating keratoplasty (PKP).

Setting: Department of Ophthalmology, Ege University, School of Medicine, Izmir, Turkey.

Methods: Patient group (PG) included 9 patients (12 eyes) who had clinically successful PKP in our department. The control group (CG) included 12 people (18 eyes) who had no ocular disease other than refractive errors. Those with a visual acuity level less than 20/25 were not included in the study. Contrast sensitivity levels and light threshold values of the central retina were measured; scanning-slit corneal topography–pachymetry and aberrometric analysis were performed.

Results: There were no statistical difference in terms of age (32.55 years ± 9.25 (SD) in PG, 36.75 ± 5.85 years in CG; P = .53), cylinder power in plus form (2.60 ± 1.25 diopter (D) in PG, 2.79 D ± 2.51 D in CG; P = .88), and spherical equivalent of refractive errors (−3.66 ± 3.57 D in PG, −5.52 ± 3.37 D in CG; P = .29) between the PG and CG. Cambridge low-contrast grating scores were 96.5 ± 41.1 in grafted eyes and 148 ± 27.7 in CG (P = .004). Central retinal light sensitivity was measured as 29.91 ± 2.39 db in PG and 33.08 ± 1.56 db in CG (P = .001). In corneal topographic analysis, mean kappa intercept was 0.69 ± 0.37 mm in PG and 0.55 ± 0.24 mm in CG (P = .20). Lower-order Zernike root mean squares (RMS) were 7.30 ± 3.89 μm for PG and 8.58 ± 3.46 μm for CG (P = .37). However, higher-order Zernike RMS were 2.15 ± 0.78 in PG and 0.38 ± 0.10 in CG, which is a statistically significant difference (P<.001).

Conclusions: Even though the clinically successful PKP patients have correctable amount of spherocylindrical refractive errors with spectacle lenses, they still have reduced visual quality because of the significantly high amount of higher- order aberrations when compared with naturally occurring refractive errors.