Comparison of wound architecture in implantable collamer lens surgery: Self-sealing single-plane opposite clear corneal incision versus main surgical incision

The Efficacy of Paired Opposite Clear Corneal Incisions Correcting Preexisting Low-to-Moderate Astigmatism in Implantable Collamer Lens Surgery

PURPOSE

To evaluate the efficacy of paired opposite clear corneal incisions (OCCIs) in Implantable Collamer Lens (ICL; STAAR Surgical) implantation surgery for correcting preexisting low-to-moderate astigmatism and observe their influence on corneal aberration.

METHODS

This prospective controlled randomized study included 123 eyes: 73 eyes in the ICL surgery group (control group) and 50 eyes in the ICL combined with OCCI group (OCCI group). All patients had corneal astigmatism between 0.50 and 3.00 D. Parameters considered included uncorrected distance visual acuity (UDVA), corrected distance visual acuity (CDVA), refraction, keratometry, slit-lamp biomicroscopy, indirect ophthalmoscopy, corneal topography, and higher order aberrations (HOAs). The Alpins method was used to analyze the correction of astigmatism. The follow-up period lasted for 12 months.

RESULTS

Both groups showed a statistically significant improvement in mean UDVA and CDVA after surgery. At 1 and 12 months, the OCCI group had statistically better UDVA than the control group (P = .021 and .01). The OCCI group showed a significant reduction in mean refractive astigmatism from -0.835 ± 0.274 to -0.535 ± 0.353 and -0.450 ± 0.346 D postoperatively (P < .05) after 1 and 12 months. No significant change was observed in the control group (P > .05). The average magnitude of surgically induced astigmatism (SIA) was 0.911 ± 0.442 and 0.811 ± 0.397 D at 1 and 12 months postoperatively, respectively, in the OCCI group, which was slightly lower than the target induced astigmatism. The difference in SIA between the OCCI and control groups was significant by the end of 1 and 12 months postoperatively (P < .0001). The mean correction index was below 1, suggesting an undercorrection effect caused by clear corneal incisions in the opposite direction. HOAs increased in both the control and OCCI groups after surgery (t = 5.668, P < .0001, t = 3.773, P = .0003, respectively), with oblique trefoil only significantly increasing in the OCCI group.

CONCLUSIONS

This study demonstrated that OCCIs represent a secure, efficient, reliable, and long-term technique for reducing preexisting low-to-moderate corneal astigmatism during ICL surgery. However, OCCIs did not show any advantageous impact in terms of wavefront aberrations when compared to the traditional single-incision method. The presence of oblique trefoil may be the main contributor to the alteration of HOAs during OCCI surgery. [J Refract Surg. 2024;40(1):e20-e29.].

Management of low astigmatism in implantable collamer lens surgery: opposite clear corneal incisions vs toric implantable collamer lens

PURPOSE

To compare 2 techniques to correct low astigmatism during implantable collamer lens (ICL) surgery: astigmatic opposite clear corneal incisions (OCCIs) and toric ICL (T-ICL).

SETTING

Arruzafa Ophthalmological Hospital, Cordoba, Spain.

DESIGN

Randomized prospective comparative study.

METHODS

The study comprised 152 myopic eyes undergoing ICL surgery. Patients were separated into 2 groups: Group 1 (57 patients; 76 eyes) received a spherical ICL with OCCIs and Group 2 (53 patients; 76 eyes) received a T-ICL. The inclusion criteria were refractive astigmatism up to 1.50 diopters (D), regular corneal astigmatism up to 2.00 D (Sim K, Pentacam), and agreement between the refractive and topographic corneal cylinders (discrepancies less than 30 degrees axis or 0.50 D). The outcomes were evaluated after a 1-month follow-up.

RESULTS

The T-ICL group achieved a mean postoperative spherical equivalent refraction and refractive astigmatism of -0.04 ± 0.17 D and -0.03 ± 0.12 D, respectively, vs -0.14 ± 0.33 D and -0.20 ± 0.36 D, in the OCCI group ( P < .001). Postoperative refractive astigmatism of less than 0.25 D was achieved in 94.74% of cases in the T-ICL group vs 73.68% in the OCCI group. Undercorrection of corneal astigmatism occurred in the OCCI group with a surgically induced astigmatism of 0.48 ± 0.24 D and correction index = 0.46.

CONCLUSIONS

Both the T-ICL and OCCI techniques provided excellent results in terms of safety and efficacy. T-ICL surgery was shown to be more predictable and accurate for correcting low astigmatism with a lower postoperative spherical equivalent and less residual astigmatism compared to incisional management.