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

Abstract

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.

Keywords: CK; conductive keratoplasty; post-LASIK; presbyopia.

Figure 1

Cylindrical change from preoperative for non- and post-LASIK groups. One week, 1 month, 3 months, 6 months, and 1 year postoperative absolute cylinder change from preoperative was calculated for the non- and post-LASIK groups.

Figure 2

The error from the intended correction for non- and post-LASIK groups. The predictability at 1 week, 1 month, 3 months, 6 months, and 1 year postoperative for the non- and post-LASIK groups was evaluated by calculating the distance of manifest refraction spherical equivalent value from the intended correction.

Figure 3

Comparison of corneal thickness, amount of correction made during LASIK, and residual corneal bed thickness after LASIK and the predictability at 3 months postoperative for both groups.