A Comparative Study Of The Vector Analysis Method To Evaluate The 5-Year Long-Term Efficacy Of Toric Implantable Collamer Lens And Implantable Collamer Lens Plus Steep Meridian Corneal Relaxing Incision For Moderate Astigmatism

This retrospective study aimed to compare the long-term effectiveness and stability of postoperative astigmatism correction in patients with refractive errors associated with moderate astigmatism by observing two correction options: toric implantable collamer lens (TICL) implantation and implantable collamer lens (ICL) plus steep meridian corneal relaxing incision (SM-CRI).

 Department of Refractive Surgery, Chongqing Aier Eye Hospital, Chongqing, China

Refractive error patients with preoperative integrated optometry of 1.00D-2.00D astigmatism were included in 254 eyes of 130 patients respectively, and were divided into a TICL implantation group via a conventional horizontal incision and an ICL implantation group via a modified steep meridian corneal relaxing incision (SM-CRI group). Comparative studies of their UDVA and CDVA at 1,3,6,12 months and 5 years postoperatively, as well as further comparisons between the two surgical modalities using Alpins Astigmatism Vector Analysis of target-induced astigmatism (TIA), surgically-induced astigmatism (SIA), difference vectors (DV), correction indices (CI), and angle of error (AE) at various times.

Both groups' mean postoperative UDVA and CDVA significantly improved following surgery. At the 5-year follow-up, the TICL group shown stability in astigmatism correction (P > 0.05), whereas the SM-CRI group displayed a trend toward regression (P < 0.01). The DV at 5 years postoperatively revealed that the TICL group had less residual astigmatism than the SM-CRI group (P < 0.01). The mean size of the SIAs was 1.58 ± 0.44 and 0.92 ± 0.37 diopters, respectively (P < 0.001); the TICL group's CI was closer to 1 (0.95 vs. 0.68); and approximately 98% of the TICL group had an error angle within ±15°, as opposed to 89% in the SM-CRI group. The TICL group had an absolute mean AE of 6.30±3.41, while the SM-CRI group had an AE of 13.32±9.03.

In refractive error patients with moderate astigmatism, TICL implantation provides better long-term visual outcomes and better stability of astigmatism correction postoperatively than ICL plus steep meridian corneal relaxing incision.