Conductive keratoplasty for the treatment of presbyopia: comparative study between post- and non-LASIK eyes

PURPOSE To evaluate the efficacy and safety of conductive keratoplasty (CK) for the treatment of presbyopia and analyze the differences in the effects between post- and non-laser in situ keratomileusis (LASIK) eyes. Clinical preoperative factors that could affect the predictability of CK were also analyzed. METHODS The visual and refractive outcomes of CK for the treatment of presbyopia in 14 eyes of 13 post-LASIK patients (post-LASIK group mean age 50.9 ± 3.4 years) and those of 25 eyes of 25 non-LASIK patients (non-LASIK group mean age 52.4 ± 4.0 years) were studied. The clinical efficacy, safety, stability, and predictability of CK were statistically evaluated. RESULTS The mean (logarithm of the minimum angle of resolution [logMAR] ± standard deviation [SD]) of preoperative uncorrected near visual acuity (UNVA) and manifest refraction spherical equivalent (MRSE) were 0.64 ± 0.25 diopter (D) and 0.35 ± 0.48 D, respectively, in the post-LASIK group, and 0.71 ± 0.20 D and 0.64 ± 0.61 D, respectively, in the non-LASIK group. At 6 months after CK, the mean UNVA and MRSE were 0.07 ± 0.13 D and -1.59 ± 0.86 D, respectively, in the post-LASIK group, and 0.07 ± 0.12 D and -1.06 ± 0.56 D, respectively, in the non-LASIK group. At 1 year after CK, the mean UNVA and MRSE were 0.30 ± 0.17 D and -0.58 ± 0.52 D, respectively, in the post-LASIK group, and 0.28 ± 0.34 D and -1.56 ± 0.62 D, respectively, in the non-LASIK group. There was no significant difference between the two groups in either factor at 6 months postoperative (Student's t-test, P > 0.05). At 1 year after CK, all the treated eyes maintained corrected distance visual acuity better than -0.08 (logMAR). The mean cylindrical errors were within ±1.00 D in 100% of the post-LASIK and non-LASIK patients. As for the preoperative clinical factors evaluated for their potential relationship to the predictability of CK, none showed significant effect on the clinical outcomes. CONCLUSION CK is demonstrated to be safe for the treatment of presbyopia in post-LASIK patients as well as in non-LASIK patients, though needed longer observation in terms of factors affecting predictability.