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SMILE for the Correction of High Myopia With Astigmatism
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In this prospective study, the authors investigated the safety and efficacy of small incision lenticule extraction (SMILE) for the correction of high myopia greater than −10.0 diopters (D). Overall, 57% of the SMILE-treated patients achieved an uncorrected distance visual acuity of 20/20 or better with a significantly lower standard deviation of refractive accuracy (0.48 D vs 0.68 D) compared with LASIK-treated patients. The treatment was tolerated well with only one case of postoperative ectasia in a patient who vigorously rubbed the eye; however, there was an increased risk of night vision disturbances. Patient satisfaction was high and patients reported near-complete independence from glasses after treatment.
- SMILE may represent a safe and efficacious treatment for high myopia with results that may be more reproducible and predictable than LASIK.
abstract
This abstract is available on the publisher's site.
Access this abstract nowPURPOSE
To report the outcomes of small incision lenticule extraction (SMILE) for high myopia between -9.00 and -14.00 diopters (D).
METHODS
This was a prospective study of SMILE for high myopia using the VisuMax femtosecond laser (Carl Zeiss Meditec). Inclusion criteria were attempted spherical equivalent refraction (SEQ) between -9.00 and -14.00 D, cylinder up to 7.00 D, corrected distance visual acuity (CDVA) of 20/40 or better, age 21 years or older, and suitable for SMILE. The sub-lenticule thickness was 220 µm or greater, and the total uncut stromal thickness was 300 µm or greater. Patients were to be followed up for 1 year. Standard outcomes analysis was performed using 12-month data where available or 3-month data otherwise.
RESULTS
Of 187 eyes treated, data were available at 12 months for 181 eyes (96.8%) and 3 months for 4 eyes (2.1%), and 2 eyes (1.1%) were lost to follow-up. Mean attempted SEQ was -10.55 ± 1.00 D (range: -9.00 to -12.99 D). Mean cylinder was -1.19 ± 0.83 D (range: 0.00 to -4.00 D). Preoperative CDVA was 20/20 or better in 73% of eyes. Postoperative uncorrected distance visual acuity was 20/20 or better in 57% and 20/25 or better in 82% of eyes. Mean SEQ relative to target was -0.22 ± 0.48 D (range: -1.63 to +1.38 D), 66% ± 0.50 D and 93% ±1.00 D. Mean SEQ 12-month change was -0.08 ± 0.34 D (range: -1.75 to +0.88 D). There was loss of one line of CDVA in 4% of eyes, and no eyes lost two or more lines. Contrast sensitivity was unchanged. Patient satisfaction was 8 or more out of 10 in 94% and 6 or more in 99% of patients.
CONCLUSIONS
Outcomes of SMILE for myopia greater than -9.00 D at 3 to 12 months showed excellent efficacy, safety, stability, and predictability, with high patient satisfaction. [J Refract Surg. 2022;38(5):262-271.].
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Small Incision Lenticule Extraction (SMILE) for the Correction of High Myopia With Astigmatism
J Refract Surg 2022 May 01;38(5)262-271, DZ Reinstein, TJ Archer, RS Vida, GI Carp, JFR Reinstein, T McChesney, JG PotterFrom MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.
SMILE and LASIK for myopia; SMILE is not routinely used for high myopia
Small-incision lenticule extraction (SMILE) is now an option for patients seeking refractive surgery for myopia and/or astigmatism for a sphere up to –10.00 D and a cylinder up to –5.00 D. For patients with high myopia that is greater than –10.00 D sphere, LASIK has been performed with parameters optimized to allow treatment of such high refractive errors, although the risk of night vision symptoms persists. For patients with high myopia, SMILE may be an option; by retaining the stronger anterior corneal lamellae, the risk of ectasia and higher order abberations may be reduced compared with LASIK.
This study evaluated SMILE for high myopia
Patients aged 21 years or older with a spherical equivalent between –9.00 D and –14.00 D, cylinder up to 7.00 D, corrected distance visual acuity (CDVA) of 20/40, and able to have SMILE were included in this prospective study. Of the 187 eyes included, most (n = 181 eyes) had 12-month follow-up data. The SMILE treatments were performed using the VisuMax 500-kHz femtosecond laser (software version 2.4.0; Carl Zeiss Meditec AG). The mean refractive errors attempted were a spherical equivalent (SEQ) of –10.55 ± 1.00 D (range, –9.00 to –12.99 D) and cylinder of –1.19 ± 0.83 D (range, 0.00 to –4.00 D). Preoperative CDVA was 20/20 or better in 73% of the eyes.
The results showed that SMILE, relative to LASIK, was effective and safe for high myopia
Visual results
Following SMILE, the uncorrected distance visual acuity (UDVA) was 20/20 or better in 57% and 20/25 or better in 82% of the eyes, and the mean SEQ relative to target was –0.22 ± 0.48 D (range, –1.63 to +1.38 D), 66% ± 0.50 D, and 93% ± 1.00 D. The mean SEQ 12-month change was –0.08 ± 0.34 D (range, –1.75 to +0.88 D).
Safety
A line of CDVA was lost in 4% of the eyes and contrast sensitivity was unchanged. Patient satisfaction was high and rated as 8 or more in 94% and 6 or more (out of 10) in 99% of the patients. Adverse events included a case (0.5%) of grade 1 sterile marginal keratitis, managed by prednisolone, and a case of ectasia. Refractive and visual outcomes were at least equivalent to and possibly better than those reported with LASIK. UDVA within one line of CDVA or better was achieved in 87% of eyes and SEQ refraction was within ±0.50 D in 66% and within ±1.00 D in 96% of eyes. SMILE had a statistically significant lower standard deviation of refractive accuracy than LASIK (0.48 D vs 0.68 D, respectively).
Patients having SMILE for high myopia are at risk of night vision disturbances
Due to night vision disturbances after SMILE and LASIK, phakic IOLs remain an alternative for patients with high myopia and can provide greater refractive accuracy. Clinicians and patients will need to consider the risk of an intraocular procedure when choosing their preferred method for refractive correction in high myopia.