Unusual Internal Astigmatism Due to Severe Capsule Contraction Syndrome

PURPOSE

To describe a case of severe capsule contraction syndrome causing significant astigmatism due to intraocular lens (IOL) folding.

METHODS

Case report.

RESULTS

Capsule fibrosis and contraction resulted in bending of the hydrophilic IOL along its long axis. Anterior Nd:YAG capsulotomy resolved the situation and restored the patient's visual acuity.

CONCLUSIONS

Hydrophilic IOLs are more susceptible to capsule contraction due to the increased flexibility of highly hydrated materials. They should be avoided in patients at risk of capsule contraction to prevent ocular complications. [J Refract Surg. 2018;34(1):65-67.].

[Problems and challenges in the development of corneal refractive surgery]

Corneal refractive surgery, as one of the common visual correction methods, has been increasingly accepted in China. There are a large number of people in China who undergo the corneal refractive surgery due to the high incidence of myopia in the country. It is essential that the safest and most effective surgery should be used to correct refractive errors in the cases involved with relatively normal eyes and corneas. In recent years, corneal refractive surgery has been rapidly developing with new technologies and techniques emerging all the time, such as SMILE (small incision lenticule extraction) surgery, which has been extensively applied in China since five years ago when it was approved by FDA. However, little known are these new technologies and techniques, and the clinical and basic researches need further investigations by various approaches including histopathology and molecular biology, combined with mathematics, computer science, physics, chemistry and corneal biomechanics. To achieve minimal tissue damage and optimal clinical outcomes on visual quality by corneal refractive surgery requires the multidisciplinary partnerships of medical practitioners and researchers. (Chin J Ophthalmol, 2018, 54: 3-6).

[Relation between corneal biomechanical alteration after small incision lenticule extraction and intraoperative cutting thickness]

Objective: To explore the rule of corneal biomechanical alteration with residual stromal thickness (RST) and percent tissue altered (PTA) after small incision lenticule extraction (SMILE) and to determine the factors influencing postoperative corneal biomechanical properties. Methods: In this retrospective study, a total of 184 patients (184 right eyes) who underwent SMILE in Tianjin Eye Hospital Refractive Surgery Center from January 2019 to January 2020 were enrolled. There were 83 males and 101 females with age of (24.6±5.8) years. Corneal biomechanical parameters, including DA ratio, stiffness parameter at the first applanation (SPA1) and integrated radius (IR), were measured with Corvis ST preoperatively and at 3 months postoperatively. The association between PTA, RST and the changes of DA ratio, SPA1 and IR was assessed by linear and nonlinear regression analyses. Stepwise multivariate regression analyses were conducted to explore the factors associated with postoperative corneal biomechanical parameters with age, sex, anterior mean keratometry, spherical equivalent, postoperative central corneal thickness (CCT) and preoperative corneal biomechanical parameters as covariates. Preoperative and postoperative data were compared using the paired t test. Correlations were determined by the Pearson or Spearman analysis. Results: The alterations at 3 months postoperatively of DA ratio, SPA1 and IR were 1.33 (30.0%), 28.05 (26.0%) and 2.56 (34.0%), respectively. The changes before and after surgery were statistically significant (t=35.52, -28.00, 36.95, P<0.01). The best-fit curve showed that the changes of DA ratio, SPA1 and IR increased with the decrease of RST or increase of PTA. When the RST was<280 μm or the PTA was>28%, the slope of the change of DA ratio curve was significantly increased. Multivariate regression models showed that the factors with the greatest influence on postoperative DA ratio, SPA1 and IR were preoperative DA ratio (Sβ=0.489, P<0.01), preoperative SPA1 (Sβ=0.483, P<0.01) and preoperative IR (Sβ=0.471, P<0.01), respectively. The CCT was the second factor that influenced postoperative DA ratio and SPA1 (Sβ=-0.238, P<0.01; Sβ=0.326, P<0.01). Conclusions: The changes of DA ratio, SPA1 and IR following SMILE increased with the decrease of RST or increase of PTA. With the RST<280 μm or the PTA>28%, the alteration of DA ratio significantly accelerated. Preoperative corneal biomechanical properties and postoperative CCT were main factors influencing corneal biomechanical properties after SMILE. (Chin J Ophthalmol, 2021, 57: 104-112).

Feasibility, Safety, and Outcomes With Standard Versus Differential Spot Distance Protocols in Eyes Undergoing SMILE for Myopia and Myopic Astigmatism

PURPOSE

To study the feasibility, safety, comparison of intraoperative ease of dissection, and immediate visual outcomes with standard versus differential small incision lenticule extraction (SMILE) spot settings in eyes undergoing bilateral SMILE for myopia or myopic astigmatism.

METHODS

One hundred eyes of 50 patients (mean age: 25.4 years) were randomized to receive standard settings (4.5-µm spot and track spacing in cap and lenticule interface) in one eye and differential settings (4.5-µm spot and track spacing in cap interface and 4.2 µm in lenticule interface) in the contralateral eye. Opaque bubble layer (OBL) was graded using a new grading system and a surgeon questionnaire was obtained to grade the ease of dissection (from 0 to 5, with 5 being the easiest) at the end of each surgery. Visual results and optical quality were analyzed at 1 day, 2 weeks, and 3 months postoperatively.

RESULTS

The mean OBL score was significantly lower in the differential group (26.3%) compared to the standard group (35.3%) (P < .01). Consequently, the mean dissection score was significantly higher in the differential group (4.01) compared to the standard group (3.57) (P < .01). The uncorrected distance visual acuity, Objective Scatter Index, modulation transfer function cut-off, and higher order aberrations were comparable with no statistically significant difference between both groups at 1 day, 2 weeks, and 3 months postoperatively (P > .05 for all parameters). No eye in either group had any intraoperative or postoperative complication affecting visual recovery.

CONCLUSIONS

Differential spot settings resulted in less intraoperative OBL and easy separability. However, the visual results and optical quality were comparable between groups. [J Refract Surg. 2021;37(5):294-302.].

[Western Blot analysis of type I, III, V, VI collagen after laser epithelial keratomileusis and photorefractive keratectomy in cornea of rabbits]

PURPOSE

Use immunohistochemical staining and Western Blot analysis to observe and compare the accurate dynamic changes of type I, III, V, VI collagen in the wound healing processes of the rabbit cornea which underwent LASEK or PRK to investigate the possible mechanism of corneal haze and myopic regression.

METHODS

New Zealand White rabbits were divided into 8 groups: normal control group (n=6), 1 day, 7 days, 1, 3, 4, 5 and 6 month groups (n=14). Every rabbit underwent LASEK in one eye while the other one with PRK. We use immunohistochemical staining and Western Blot analysis to compare the wound healing process of dynamic change of the type I, III, V and VI collagen in rabbit cornea of every time point. The results were analysised with data analysis software.

RESULT

Immunohistochemical staining and Western Blot analysis showed that after LASEK, the cornea wound healing with type I and III collagen were much faster than PRK, and the wound response was also much weaker. Whereas for type V and VI collagen, their dynamic changes were resemble between LASEK and PRK, they both reached the peak value after 3 months since the surgery, but LASEK group returned to normal earlier than PRK. The value of these two types of collagen after PRK were higher than LASEK. The changes of these four types of collagen may offer us at least partial explaination to the difference between formation between corneal haze and refractive regression.

CONCLUSIONS

There were significant differences between LASEK and PRK on type I, III, V and VI collagens or the time of reacting, reaching apex and returning to normal . LASEK had slighter intensity of reaction. The results indicate that there is excessive aggradation of collagens after PRK, it may be the histological foundation of obvious haze and myopia regression.

Some aspects of wave aberrations of the human eye and supervision: a review

Supervision is defined by a visual acuity of 20/10 or 20/8 and may be attained by custom-correcting the aberrations of higher order of the human eye. Higher order aberrations are those aberrations which are left in the eye after having corrected lower order aberrations, i.e., defocus (myopia, hypermetropia) regular astigmatism, and which can be corrected by ordinary spectacle lenses or contact lenses. Higher order aberrations are found to a higher or lesser degree in normal or pathological human eyes and in eyes having undergone conventional corneal surgery. According to custom keratorefractive surgery limits, given by the neural visual apparatus and the receptor mosaic, supervision (i.e., 20/10 or even 20/8) may be attained. A number of dedicated sensors have been developed in recent years that are able to detect and measure aberrations of the wave front which is a sensitive procedure for the determination and surgical control of the optical quality of the eye. Not every custom keratorefractive procedure results in supervision, however. This is because not every "normal" eye is able to reach such limits because of its basic design (anatomy or function) and also because keratorefractive procedures neglect the plastic behaviour of the cornea. The plasticity of the central neural system may furthermore interact with corrected or non-corrected visual function.

Refractive Corneal Lenticule Extraction With the CLEAR Femtosecond Laser Application

PURPOSE

The aim of this study was to evaluate a new femtosecond laser application for refractive corneal lenticule extraction with suction control and computerized regulation of centration and alignment (Ziemer CLEAR).

METHODS

This was a retrospective, consecutive, noncomparative case series study. Patients undergoing CLEAR for spherical equivalent (SE) between -3 and -10 D, evaluating SE, defocus equivalent, refractive astigmatism, visual acuity, and centration at 10 months were evaluated in the study.

RESULTS

Fifty-three eyes of 42 patients (mean age 40.4 ± 8.6 years) were included, with preoperative SE -5.99 ± 1.49 D and mean corrected distance visual acuity (CDVA) of 0.05 ± 0.07 logMAR. With no suction losses, an intact lenticule was extracted in all eyes. In 6 eyes, peripheral adhesion was resolved by lenticulerrhexis, and in 1 eye, the incision was opened by a crescent blade. Moderate interface inflammation occurred in 3 eyes. At day 1, in the 42 eyes with uneventful surgery, the mean CDVA was 20/27, whereas in the 11 eyes with extra surgical manipulations, it was 20/36 ( P = 0.04). At 10 months, for the 53 eyes, the mean uncorrected distance visual acuity was 0.05 ± 0.09 logMAR; in 37 eyes (70%), it was 20/25 or better; and the mean CDVA was 0.04 ± 0.06 logMAR. Eight eyes (15%) lost 1 logMAR line. The mean SE was -0.13 ± 0.15 D. The mean defocus equivalent was 0.33 ± 0.32 D, with 46 eyes (87%) ≤0.50 D and 52 eyes (98%) ≤1 D. Refractive astigmatism was ≤0.50 D in 48 eyes (90%). The efficacy index was 1.00, and the safety index was 0.98. The mean decentration from the corneal vertex was 0.28 ± 0.07 mm.

CONCLUSIONS

The application yielded good predictability, efficacy, and safety. Slower visual recovery was observed after extra surgical manipulations.

Comparison of 110- and 145-µm Small-Incision Lenticule Extraction Cap Thickness: A Randomized Contralateral Eye Study

PURPOSE

To investigate the visual, refractive, and biomechanical outcomes of small incision lenticule extraction (SMILE) with two different cap thicknesses.

METHODS

Thirty-four patients were included in this prospective, randomized, contralateral eye study. Subjects were randomized to receive SMILE surgery with a 110-m cap thickness in one eye and 145-µm cap thickness in the fellow eye. Uncorrected and corrected distance visual acuity, contrast sensitivity (CS), total higherorder aberrations (THOAs) and corneal biomechanical properties were compared 3 months after surgery.

RESULTS

Postoperative refractive and visual outcomes, CS and THOAs were similar between the two groups ( P > 0.05 for all parameters). At 3 months postoperatively, there was a significant difference in Corvis ST Biomechanical Index (CBI); stiffness parameter at first applanation (SP A1), and Integrated Radius between the two groups (all P < 0.05).

CONCLUSIONS

Eyes with thicker SMILE corneal caps showed no advantage regarding visual acuity, CS and THOAs over eyes with thinner caps. However, higher cap thickness may result in better corneal biomechanical properties postoperatively.

Femtosecond Laser-Assisted Small Incision Allogeneic Endokeratophakia Using a Hyperopic Lenticule in Rabbits

Purpose

To investigate the morphologic and histopathologic changes in allogeneic endokeratophakia using hyperopic lenticules derived from small-incision lenticule extraction (SMILE).

Methods

Six New Zealand rabbits (12 eyes) were included in this experiment and randomly and evenly divided into donor and recipient groups. The donor group underwent bilateral hyperopic SMILE surgery, and the concave lenticules were implanted into eyes in the recipient group. Corneal topography and anterior segment optical coherence tomography (OCT) examinations were performed at 1 day, 1 week, 1 month, and 5 months after surgery. All eyes were enucleated 5 months after surgery. Hematoxylin and eosin (HE) staining and transmission electron microscopy (TEM) were used to observe the corneal morphology in the recipient group.

Results

No complications were observed, and the corneas remained transparent in the follow-up period. There was mild corneal edema within 1 week after surgery. Slit-lamp microscopy and OCT showed that the lenticules were gradually integrated with the surrounding corneal stroma. HE staining showed that the arrangement of corneal collagen was regular. The boundary between the lenticules and surrounding tissue could be identified with HE staining and TEM, and no inflammatory cells were found under TEM. The corneal Km values were significantly lower at 5 months postoperatively compared to preoperatively (P < 0.05).

Conclusions

This pilot study showed that allogeneic hyperopic SMILE lenticule endokeratophakia seems to be safe and feasible.

Translational Relevance

Allogeneic hyperopic SMILE lenticule endokeratophakia may be applicable for the correction of corneal regression, ectasia, ultra-high myopia, or keratoconus.

Refractive outcomes of small lenticule extraction (SMILE) Pro® with a 2 MHz femtosecond laser

PURPOSE

To evaluate the initial visual outcomes of Small Incision Lenticule Extraction (SMILE) Pro® using a 2 MHz femtosecond laser (VisuMax 800, Carl Zeiss Meditec) and to assess the efficacy, safety, predictability, accuracy, and complication rate.

METHODS

This retrospective analysis included eyes which underwent the SMILE Pro® procedure using VisuMax 800 femtosecond laser to correct myopia. All surgeries were performed by one surgeon (DB). Follow-up was conducted 3 months postoperatively to evaluate visual outcomes after neuroadaptation, corrected visual acuity (CDVA) and intra- and postoperative complications.

RESULTS

One hundred and fifty-two eyes of 82 patients (mean age 31 ± 6 years) results at 3 months are presented. The mean spherical equivalent (SE) was - 4.44 ± 1.86 D preoperatively while -0.24 ± 0.32 D postoperatively. 99% of eyes achieved SE within ± 1.0 D of attempted correction and 91% were within ± 0.5 D. Efficacy index was 0.93 while the safety index was 1. No complications occurred intra- or postoperatively. No eyes lost more than 1 line of their preoperative CDVA. All highly myopic eyes (- 6.25 to - 10.00 D; n = 18) achieved 20/20 at 3 months postoperatively and were within 0.5 D from the attempted SE and no eyes lost more than 1 line of CDVA.

CONCLUSION

The SMILE Pro® is a safe, efficient, and predictable procedure for the treatment of myopia and myopic astigmatism, with comparable results of conventional SMILE surgery. High myopic eyes achieve better results than low and moderate myopia. No complications were recorded in our patients.

Evaluation of the Effects of Myopic Astigmatism Correction and Anterior Corneal Curvature on Functional Optical Zone After SMILE

PURPOSE

To evaluate the influence of different degrees of myopic astigmatism correction and preoperative anterior corneal curvature on the functional optical zone (FOZ) following small incision lenticule extraction (SMILE).

METHODS

In this retrospective study, 68 patients (106 eyes) treated with SMILE were grouped according to myopic astigmatism correction: control (0.00 diopters [D]), moderate astigmatism (-0.50 to -2.00 D), and high astigmatism (> -2.00 D). The FOZ was measured and compared between the three groups for 3 months. Correlations between attempted correction, anterior corneal curvature, corneal aberrations, and the FOZ were analyzed.

RESULTS

The preoperative mean treatment spherical equivalent was comparable among the three groups. The average FOZ was 5.06 ± 0.24 mm in the control group, 5.19 ± 0.25 mm in the moderate astigmatism group, and 5.35 ± 0.20 mm in the high astigmatism group The FOZ showed statistically significant differences among the three groups (P < .001), particularly between the high astigmatism group and the other two groups (P < .001 and .018). Correlation analysis showed that the total higher order aberrations, coma, and spherical aberration change were correlated with the FOZ (P < .001). Preoperative steep keratometry, average keratometry, and corneal astigmatism were significantly correlated with the FOZ (P < .05). The correlation remained after excluding the influence of attempted correction on the FOZ (P < .05). After adjusting for other risk factors using multiple linear regression analysis, there was still a significant positive association between preoperative steep keratometry and the FOZ (P < .001).

CONCLUSIONS

Patients with higher myopic astigmatism achieved a larger FOZ and less induced horizontal coma than the control and moderate astigmatism groups. A larger FOZ after SMILE can be achieved in eyes with steeper keratometry. [J Refract Surg. 2023;39(2):135-141.].

Relationship between postoperative residual refractive error and preoperative corneal stiffness in small-incision lenticule extraction

PURPOSE

To explore the relationship between postoperative residual refractive error and preoperative corneal stiffness after small-incision lenticule extraction (SMILE).

SETTING

Hospital clinic.

DESIGN

Retrospective cohort study.

METHODS

Corneal stiffness was evaluated using the stress-strain index (SSI). Associations between postoperative spherical equivalent (SE) and corneal stiffness were determined using longitudinal regression analysis after adjustment for sex, age, preoperative SE, and other variables. The cohort was divided into halves to compare risk ratios for residual refraction in corneas with different SSI values. Low SSI values were defined as having less-stiff corneas and others as having stiffer corneas.

RESULTS

287 patients (287 eyes) were included. Greater undercorrection was found in less-stiff corneas across all follow-up timepoints (less-stiff corneas: 1 day: -0.36 ± 0.45 diopters [D], 1 month: -0.22 ± 0.36 D, and 3 months: -0.13 ± 0.15 D; stiffer corneas: -0.22 ± 0.37 D, -0.14 ± 0.35 D, and -0.05 ± 0.11 D, respectively). Postoperative refraction exhibited a mean 0.05 D undercorrection for every 0.1-unit decrease in the SSI after adjustment for variables. The SSI accounted for nearly 10% of the variance in refractive outcomes. Less-stiff corneas increased the risk ratio of postoperative absolute SE >0 D and ≥0.25 D by 2.242 (95% CI, 1.334-3.768) and 3.023 (95% CI, 1.466-6.233), respectively, compared with stiffer corneas.

CONCLUSIONS

Postoperative residual refractive error was associated with preoperative corneal stiffness. Patients with less-stiff corneas had a 2- to 3-fold increased risk of residual refractive error after SMILE. Preoperative analysis of corneal stiffness can help modify nomogram algorithms of surgery and improve the predictability of refractive outcomes.

Impact of the preoperative cylinder on astigmatism correction in femtosecond lenticule extraction (FLEX): a prospective observational study

PURPOSE

To explore the impact of the preoperative manifest cylinder on astigmatism correction via femtosecond lenticule extraction (FLEX), or small incision lenticule extraction (SMILE).

METHODS

This was a prospective observational study. Eyes were categorized into mild (n = 88), moderate (n = 46), and severe (n = 53) astigmatism groups, based on the preoperative manifest cylinder. Vector analysis was conducted with the back vertex distance set at 12 mm. The primary outcome was the correction index (CI), with secondary outcomes including the safety, efficacy, predictability, and vectoral alterations related to FLEX.

RESULTS

The average target-induced astigmatism was 0.45 ± 0.20 D, 0.95 ± 0.17 D, and 1.99 ± 0.65 D in the three groups (P < 0.001), and the average CI was 1.12± 0.05, 1.01 ± 0.03, and 0.95 ± 0.02 (P = 0.020), with the severe astigmatism group displaying a notably lower CI. The efficacy, safety, predictability, or stability of FLEX did not demonstrate any significant differences among the three groups. The CIs exhibited a significant difference in eyes with with-the-rule (WTR) astigmatism and against-the-rule (ATR) astigmatism from the mild to severe astigmatism group. In eyes with oblique astigmatism, the average CI exceeded one.

CONCLUSION

Patients with manifest cylinder exceeding 1.25 D have a heightened risk of under-correction in WTR and ATR astigmatism compared to those with mild astigmatism, and mild over-correction may occur in cases of oblique astigmatism.

Topographic and surgical risk factors for high postoperative residual astigmatism after small incision lenticule extraction in patients with different degrees of myopia: a retrospective cohort study

BACKGROUND

To evaluate the possible topographic and surgical risk factors for high postoperative residual astigmatism in patients who undergo small-incision lenticule extraction (SMILE) surgery and have different myopia degrees.

METHODS

A retrospective cohort study was conducted, and patients who underwent SMILE surgery were enrolled. A total of 80 and 150 eyes from 40 to 75 individuals, respectively, were selected as the low myopia and high myopia groups. The demographic data, visual acuity, refraction, topographic parameters and surgical settings were recorded. Multiple linear regression with interaction tests were performed to survey the risk factors for high postoperative residual astigmatism in each group.

RESULTS

Five (6.25%) and 9 (6.00%) eyes presented with high postoperative residual astigmatism in the low myopia and high myopia groups, respectively, but these differences were not significant (P = 0.569). A steep corneal curvature was correlated with a greater risk of high postoperative residual astigmatism in the low myopia group (P = 0.015), while a higher degree of cycloplegic cylinder power, steeper corneal curvature, greater topographic cylinder power, smaller optic zone and longer incision length were associated with a high rate of postoperative residual astigmatism in the high myopia group (all P < 0.05). In addition, the interaction effects of cycloplegic and topographic cylinder power and longer incision length on the incidence of high postoperative residual astigmatism development were more evident in the high myopia group than in the low myopia group (all P < 0.05).

CONCLUSIONS

A steep corneal curvature correlates with a high risk of high postoperative residual astigmatism after SMILE surgery, and a higher degree of cycloplegic and topographic cylinder and longer incision are associated with high postoperative residual astigmatism in individuals with high myopia.

[Use of corneal pachymetry in ocular hypertension and chronic glaucoma]

Among the numerous corneal variables that may influence the determination of the "true" intraocular pressure (IOP) from applanation tonometry measurements and considering the still non conclusive scientific data on all the different aspects of this topic, the measurement of the central corneal thickness (CCT) may be an interesting diagnosis tool in hypertensive and glaucomatous patients. As far as the physiologic variability of the corneal thickness is considered, the measurement of CCT can potentially become an important confounding variable when measuring applanation tonometry in patients with ocular hypertension. It could also improve the management of patients with normal tension glaucoma and patients with suspicious optic discs. In these three groups, the measurement of CCT may be useful in determining if there is an artefactual error in the IOP measurement due to a thicker (too high) cornea or thinner (too low) cornea. Therefore the IOP corrected by CCT may change or influence a decision to initiate or modify treatment. CCT measurement has also proved to be crucial in patients who have undergone laser refractive surgery.

Changes in relative peripheral refraction and optical quality in Chinese myopic patients after small incision lenticule extraction surgery

PURPOSE

To observe changes in retinal refraction difference values (RDV) and aberrations after small incision lenticule extraction (SMILE) surgery and evaluate their correlations.

METHODS

This study recruited 112 patients (112 eyes) who underwent SMILE for myopia. Participants were classified into the Low and Moderate Myopia group (LM, -0.50 to -6.0 D) and High Myopia group (HM, >-6.0 D) according to the central spherical equivalent (SE). RDVs in the five retinal eccentricities from 0° to 10°, 10° to 20°, 20° to 30°, 30° to 40°, and 40° to 53° are recorded as RDV-(0-10), RDV-(10-20), RDV-(20-30), RDV-(30-40), and RDV-(40-53), respectively; additionally, RDVs have four sectors, i.e., RDV-Superior (RDV-S), RDV-Inferior (RDV-I), RDV-Temporal (RDV-T), and RDV-Nasal (RDV-N). With a 3-month follow-up, changes in RDV (ΔRDV) and changes in aberrations [Δtrefoil, Δcoma, Δspherical aberration (SA), and Δtotal higher-order aberrations (HOA)] after surgery were recorded.

RESULTS

No significant differences were observed in total RDV (TRDV), RDV-(0-53), RDV-S, RDV-I, RDV-N, trefoil, coma, and SA between the two groups before SMILE surgery. However, after SMILE, hyperopic defocus values [TRDV, RDV-(20-53), RDV-S, RDV-T, and RDV-N] in the LM group and hyperopic defocus values [TRDV, RDV-(20-53), RDV-S, and RDV-N] in the HM group were significantly lower at 3 months postoperatively than preoperatively, and the RDV-(40-53), RDV-S, and RDV-N were lower in the HM group than in the LM group. Aberrations [trefoil (vertical), coma, and HOA] in the LM group and aberrations (trefoil, coma, SA, and HOA) in the HM group were significantly higher at 3 months postoperatively than preoperatively, and the coma, trefoil(horizontal), SA, and HOA were higher in the HM group than in the LM group. In the multivariate analysis, ΔRDV-(40-53) was significantly correlated with ΔSA, and ΔRDV-T and ΔRDV-N were significantly correlated with Δcoma (horizontal).

CONCLUSIONS

Our findings suggest that SMILE reduces retinal peripheral hyperopic defocus but introduces some higher-order aberrations, especially in people with high myopia refractive errors.

Visual and Refractive Outcomes Following SMILE to Correct Myopia Performed by Surgeons in Training

PURPOSE

To assess visual outcomes and complications following small incision lenticule extraction (SMILE) performed by cornea fellows under the supervision of experienced surgeons.

METHODS

This retrospective, noncomparative case series was designed to assess outcomes following SMILE procedures performed at a large surgical center by cornea fellows between May 1, 2012 and March 30, 2015. Preoperative and postoperative uncorrected distance visual acuity (UDVA), preoperative and postoperative corrected distance visual acuity (CDVA), spherical equivalent (SE) up to -10.00 diopters (D), and complications were recorded.

RESULTS

A total of 114 patients (228 eyes) met the inclusion criteria. The mean preoperative SE was -5.79 ± 1.95 D (range: -1.75 to -10.00 D) and the mean cylinder was -2.21 ± 1.43 D (range: 0.00 to -5.50 D). At the last follow-up visit (average: 6.4 months), 94% of the patients achieved a UDVA of 20/30 or better and 96% of the patients achieved stability in their vision. Adverse events were encountered in 40 eyes (17.5%), with epithelial defect being the most common. Two patients required a second intervention to improve visual outcomes.

CONCLUSIONS

SMILE performed by cornea fellows under the supervision of an experienced surgeon is an effective and safe refractive procedure with a short learning curve and excellent visual outcomes. [J Refract Surg. 2022;38(1):28-34.].