Small optical zones with aspheric profiles in laser refractive surgery for myopia: a surgical outcome and patient satisfaction study

The effects of programmed optical zones on achieved corneal refractive power with myopic astigmatism after small incision lenticule extraction (SMILE): a vector analysis

PURPOSE

To evaluate the effects of different programmed optical zones (POZs) on achieved corneal refractive power (CRP) with myopic astigmatism after small incision lenticule extraction (SMILE).

METHODS

In total, 113 patients (113 eyes) were included in this retrospective study. The eyes were divided into two groups according to POZ: group A (6.5, 6.6, and 6.7 mm, n = 59) and group B (6.8, 6.9, and 7.0 mm, n = 54). Fourier vector analysis was applied to evaluate the error values between the attempted and achieved corneal refractive power (CRP). Alpins vector analysis was used to calculate surgically induced astigmatism (SIA), difference vector (DV), magnitude of error (ME), and astigmatism correction index (ACI). Multivariate regression analysis was performed to assess potential factors associated with the error values.

RESULTS

The error values in the group with large POZ were closer to zero, and significantly associated with the POZ at 2 and 4 mm of the cornea (β =  - 0.50, 95% confidence interval [CI] [- 0.80, - 0.20]; β =  - 0.37, 95% CI [- 0.63, - 0.10], P < 0.05, respectively). For the correction of astigmatism, the values of SIA, ME, and ACI were lower in group B than in group A (P < 0.05). The fitting curves between TIA and SIA were y = 0.83x + 0.19 (R² = 0.84) and y = 1.05x + 0.04 (R² = 0.90), respectively.

CONCLUSIONS

Smaller POZs resulted in higher error values between the achieved- and attempted-CRP in the SMILE procedure, which should be considered when performing surgery.

Refractive outcomes and safety of the implantable collamer lens in young low-to-moderate myopes

Purpose

To evaluate visual and refractive outcomes and safety of implantable collamer lens (ICL) implantation in low-to-moderate myopia.

Setting

Private Practice – Dougherty Laser Vision, Westlake Village, CA, USA.

Methods

A chart review was performed in 56 (104 eyes) consecutive patients who underwent implantation of the Visian ICL V4 model. Inclusion criteria were age between 21 and 40 years, spherical equivalent between −3.00 D and −10.00 D, and cylinder up to −5 D. Data on visual acuity, refraction, and complications were collected.

Results

The mean time to the last postoperative visit was 13.1±14.0 months (range, 2 to 50 months). The mean preoperative spherical equivalent was −6.96±1.60 D and the mean preoperative cylinder was −1.03±0.88 D. The mean preoperative corrected distance visual acuity (CDVA) was 20/20 (range, 20/15 to 20/80) that remained unchanged at last postoperative visit. At the last postoperative visit, the spherical equivalent was −0.08±0.01 D and the cylinder was 0.29±0.71 D. Comparison of postoperative uncorrected distance visual acuity (UCDVA) to preoperative CDVA indicated that 27 eyes (26%) had better postoperative UCDVA and 61 eyes (59%) had UDVA equivalent to the preoperative CDVA. Postoperatively, 4 eyes lost 1 line of CDVA and no eyes lost >1 line of CDVA. There were 32 eyes that gained at least ≥1 of CDVA. There were no intraoperative complications. Postoperatively, 3 patients (6 eyes) had dry eye, and 1 patient complained of nighttime halos in 1 eye. At the last postoperative visit, there were no eyes with lens opacity or glaucoma.

Conclusion

ICL implantation for low and moderate myopia up to −10 D in patients up to 40 years of age was safe, accurate, and efficacious. ICL implantation may be a good alternative to laser in situ keratomileusis for young myopes less than −10.00 D.