Incision-related astigmatism on the anterior and total cornea after implantable collamer lens implantation.

PURPOSE

To evaluate incision-related astigmatism (IRA) on the anterior and total cornea after implantable collamer lens (ICL) implantation through superior and temporal corneal incisions.

METHODS

The retrospective study included 141 eyes of 80 consecutive patients who underwent ICL implantation. An ocular examination was performed preoperatively and at 1 and 6 months postoperatively. The magnitude and axis of corneal astigmatism were assessed with keratometry (AstigK) and total corneal refractive power (TCRP, AstigTCRP) using a Scheimpflug camera, while the IRA obtained from keratometry (IRAK) and TCRP (IRATCRP) were evaluated using vector analysis.

RESULTS

At 6 months, AstigK significantly decreased from 1.45 ± 0.72 D to 1.15 ± 0.75 D in the superior incision group, whereas it increased from 1.70 ± 0.74 D to 1.88 ± 0.79 D in the temporal incision group (both P < 0.001). AstigTCRP significantly decreased from 1.32 ± 0.74 D to 1.09 ± 0.80 D in the superior incision group, while it increased from 1.61 ± 0.78 D to 1.83 ± 0.86 D in the temporal incision group (both P < 0.001). IRAK was 0.55 ± 0.30 D and 0.35 ± 0.25 D in the superior and temporal incision groups, respectively, while IRATCRP was 0.50 ± 0.28 D and 0.40 ± 0.26 D in the superior and temporal incision groups, respectively. IRAK was larger in the superior incision group than in the temporal incision group for both low- (P = 0.009) and high-astigmatism (P = 0.017).

CONCLUSIONS

Incisions in ICL surgery cause corneal flattening in the meridian of the incision. The superior incision had a greater IRAK compared to the temporal incision.