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Enhancement and regression rate after small incision lenticule extraction, photorefractive keratectomy and laser in situ keratomileusis: retrospective review of over 70000 cases

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First Author: S.Kim SOUTH KOREA

Co Author(s):    H. Koo   D. Lee                 

Abstract Details

Purpose:

Enhancement and Regression Rate after Small Incision Lenticule Extraction, Photorefractive Keratectomy and Laser in situ Keratomileusis : Retrospective Review of over 70000 Cases.

Setting:

Nunemiso Eye Clinic, Seoul, Republic of Korea.

Methods:

Retrospective review of 70989 cases of laser refractive operations in Nunemiso eye clinic from 2010 to 2019 was done. Uncorrected distant visual acuity(UDVA), corrected distant visual acuity(CDVA), spherical equivalent(SEQ), central corneal thickness(CCT) and tomography were measured pre and post operatively. Operative data including lenticule thickness(LT), lenticule diameter(LD) and the percentage of tissue altered(PTA) were also recorded. Patients were divided into three subgroups by the SEQ and the regression rates of three types of refractive operations were compared in each group. Also, by comparing preoperative and operative data of retreatment group and non-retreatment group, risk factor for the enhancement was analyzed.

Results:

The mean age of the total subjects was 26.8±6.5 years. Among 70989 cases of operations, SMILE was done the most(51430, 72.4%) and PRK(14757, 20.8%) and LASIK(4802, 6.8%) were followed. The overall enhancement rate was 0.4%, and it was the lowest in SMILE(0.3%) compared to PRK(0.7%) and LASIK(1.0%).The overall regression rate was 1.9% and it was also the lowest in SMILE(1.7%) compared to PRK(2.2%) and LASIK(3.9%). Regression rate for SMILE, PRK and LASIK in low myopic group was 0.3%,1.4% and 1.0%. In moderate myopic group it was 0.6%, 2.5% and 3.4% respectively, and in high myopic group it was 3.6%, 5.4% and 6.8%. Pre-operative SEQ, LT, LD, residual stromal bed(RSB) and PTA were shown to have statistical significance in difference between enhancement group versus non-enhancement group after SMILE operation.

Conclusions:

Postoperative myopic regression occurred the least in SMILE group regardless of the amount of preoperative myopic error. Although larger amount of tissue ablation with small optic zone could increase reoperation rate even after SMILE, it is still advantageous over the other surgical modalities due to the lowest enhancement rate overall. Thus, SMILE would be a safer refractive surgery with lower chance of retreatment and lower risk of regression in all myopic range.

Financial Disclosure:

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