One-stage versus two-stage bilateral implantable collamer lens implantation: a comparison of efficacy and safety

Abstract

Implantable collamer lens implantation (ICL) represents a safe and effective treatment for myopia and myopic astigmatism. To compare the outcomes of a bilateral one-stage same day approach to a two-stage approach, the databases of the University Eye Hospital Munich, Ludwig Maximilians-University and Smile Eyes Linz, Austria were screened for eyes that had undergone ICL implantation. Two-stage surgery was performed at an interval of 1 day (17 patients), 2 days (19 patients) and 1 week (2 patients). Variables analyzed were preoperative, 1-day and last follow-up uncorrected distance (UDVA) and corrected distance visual acuity (CDVA), manifest refraction, refractive spherical equivalent (SEQ), astigmatism, age, endothelial cell count (ECD), intraocular pressure (IOP) and ICL vaulting. In total, 178 eyes (100 eyes one-stage, 78 eyes two-stage) of 89 patients were included in this study. Mean follow-up was 1.1 ± 0.8 and 1.3 ± 0.5 years. Mean preoperative SEQ was - 7.9 ± 2.6 diopters (D) in the one-stage and - 8.0 ± 1.7 D in the two-stage group (p = 0.63) and improved to 0.00 ± 0.40 and - 0.20 ± 0.40 D at end of follow-up, showing slightly better stability in the one-stage group (p = 0.004). There was no difference in the efficacy (1.1 vs. 1.2, p = 0.06) and the safety index (1.2 vs. 1.2, p = 0.60) between the two groups. No eye (0%) in either group lost 2 lines or more of UDVA (p > 0.99). Refraction within ± 0.50 D and ± 1.00 D around target was achieved comparably often (89 vs. 86%, p = 0.65; 99 vs. 99%, p > 0.99). Endothelial cell loss was slightly higher in the two-stage group (1.3 vs. 4.3%). Vaulting at the final follow up was higher in the one-stage group (373.8 ± 205.4 µm vs. 260.3 ± 153.5 µm, p = 0.00007). There were no serious intraoperative complications in either group. In conclusion, this study demonstrates that both the one- and two-stage approaches are equally effective, predictable and safe. Regarding endothelial cell loss, vaulting and SEQ stability, the one-stage group showed slightly better outcomes, but these results are clinically questionable because they are so small. Larger studies are needed to quantitatively evaluate a potential benefit.

Figure 1

One-stage group. (A) Distribution of UDVA postoperatively compared to CDVA preoperatively. All eyes in both groups achieved a UDVA of 20/25 or better, and 94% in the one-stage group achieved 20/20 or better, in the two-stage group 95%. The efficacy indices were comparable one day postoperative (one-stage 1.0 ± 0.3 vs. two-stage 1.0 ± 0.2, p = 0.32) and at the last follow up (one-stage 1.1 ± 0.2 vs. two-stage 1.2 ± 0.2, p = 0.06. (B) Change in lines of CDVA and UDVA. No eye in both groups lost 2 or more lines. In the one-stage group 5 eyes (5%) lost one line, in the two-stage group 6 eyes (8%), p = 0.54. The safety index at the last follow up was not significant (one-stage 1.2 ± 0.2 vs. two-stage 1.2 ± 0.2, p = 0.6). (C) Attempted vs. achieved spherical equivalent refraction. By definition of spherical equivalent beyond 1.0 D from target refraction, no eye in either group was under- or overcorrected. (D) Distribution of manifest spherical equivalent refraction after retreatment. The number of eyes within 0.5 and 1.0 D from target refraction increased was 89% and 99% in the one-stage group, 86% and 99% in the two-stage group. There was a significant difference in the final target accuracy (p = 0.004). (E) Distribution of refractive astigmatism before and after retreatment. After one-stage ICL implantation, the number of eyes with astigmatism ≤ 0.5 and ≤ 1.0 D increased from 31 to 73%, and from to 44% to 97%. After two-stage ICL implantation, the number of eyes with astigmatism ≤ 0.5 and ≤ 1.0 D increased from 20 to 67%, and from to 36% to 96%. There was no significant difference in the final postoperative astigmatism (p = 0.09). (F) Refractive stability after enhancement. In both groups, MRSE was comparable one day postoperative (one-stage 0.20 ± 0.70 D vs. two-stage 0.20 ± 0.40 D, p = 0.48).

Figure 2

Two-stage group. (A) Distribution of UDVA postoperatively compared to CDVA preoperatively. All eyes in both groups achieved a UDVA of 20/25 or better, and 94% in the one-stage group achieved 20/20 or better, in the two-stage group 95%. The efficacy indices were comparable one day postoperative (one-stage 1.0 ± 0.3 vs. two-stage 1.0 ± 0.2, p = 0.32) and at the last follow up (one-stage 1.1 ± 0.2 vs. two-stage 1.2 ± 0.2, p = 0.06. (B) Change in lines of CDVA and UDVA. No eye in both groups lost 2 or more lines. In the one-stage group 5 eyes (5%) lost one line, in the two-stage group 6 eyes (8%), p = 0.54. The safety index at the last follow up was not significant (one-stage 1.2 ± 0.2 vs. two-stage 1.2 ± 0.2, p = 0.6). (C) Attempted vs. achieved spherical equivalent refraction. By definition of spherical equivalent beyond 1.0 D from target refraction, no eye in either group was under- or overcorrected. (D) Distribution of manifest spherical equivalent refraction after retreatment. The number of eyes within 0.5 and 1.0 D from target refraction increased was 89% and 99% in the one-stage group, 86% and 99% in the two-stage group. There was a significant difference in the final target accuracy (p = 0.004). (E) Distribution of refractive astigmatism before and after retreatment. After one-stage ICL implantation, the number of eyes with astigmatism ≤ 0.5 and ≤ 1.0 D increased from 31 to 73%, and from to 44% to 97%. After two-stage ICL implantation, the number of eyes with astigmatism ≤ 0.5 and ≤ 1.0 D increased from 20 to 67%, and from to 36% to 96%. There was no significant difference in the final postoperative astigmatism (p = 0.09). (F) Refractive stability after enhancement. In both groups, MRSE was comparable one day postoperative (one-stage 0.20 ± 0.70 D vs. two-stage 0.20 ± 0.40 D, p = 0.48).