Factors Influencing the Need for Enhancement After Laser in situ Keratomileusis

Visual outcomes of early enhancement following small incision lenticule extraction versus laser in situ keratomileusis

Purpose

To compare visual outcomes of early enhancement following small incision lenticule extraction (SMILE) versus laser in situ keratomileusis (LASIK).

Methods

Retrospective analysis of eyes (patients operated in the setting of a tertiary eye care hospital between 2014 and 2020) requiring early enhancement (within one year of primary surgery) was conducted. Stability of refractive error, corneal tomography, and anterior segment Optical Coherence Tomography (AS-OCT) for epithelial thickness was performed. The correction post regression was done using photorefractive keratectomy and flap lift in eyes, wherein the primary procedure was SMILE and LASIK, respectively. Pre- and post enhancement corrected and uncorrected distance visual acuity (CDVA and UDVA), mean refractive spherical equivalent (MRSE), and cylinder were analyzed. IBM SPSS statistical software.

Results

In total, 6350 and 8176 eyes post SMILE and LASIK, respectively, were analyzed. Of these, 32 eyes of 26 patients (0.5%) post SMILE and 36 eyes of 32 patients (0.44%) post-LASIK required enhancement. Post enhancement (flap lift in LASIK, and PRK in SMILE group) UDVA was logMAR 0.02 ± 0.05 and 0.09 ± 0.16 (P = 0.009), respectively. There was no significant difference between the refractive sphere (P = 0.33) and MRSE (P = 0.09). In total, 62.5% of the eyes in the SMILE group and 80.5% in the LASIK group had a UDVA of 20/20 or better (P = 0.04).

Conclusion

PRK post SMILE demonstrated comparable results to flap lift post LASIK and is a safe and effective approach for early enhancement post SMILE.

Survival analysis of myopic regression after small incision lenticule extraction and femtosecond laser-assisted laser in situ keratomileusis for low to moderate myopia

BACKGROUND

To report the predictive factors of myopic regression in patients who had undergone small incision lenticular extraction (SMILE) and femtosecond laser-assisted laser in situ keratomileuses (FS-LASIK) after 3-12 months of follow-up.

METHODS

This retrospective case series study recruited patients with a subjective sphere of - 1.00 to - 6.00 D myopia. SMILE was performed in 1629 eyes of 1629 patients with a subjective refraction spherical equivalent (SEQ) of - 4.57 ± 1.20 D and 1414 eyes of 1414 patients with a subjective SEQ of - 4.53 ± 1.26 D in FS-LASIK. Refractive outcomes were recorded at 1 day, 1 week, and 1, 3, 6, and 12 months postoperatively. Predictors affecting myopic regression and other covariates were estimated with a Cox proportional hazard (Cox PH) model for the two surgical methods.

RESULTS

At 12 months, no significant difference was evident in the efficacy (P = 0.934), predictability (P = 0.733), or stability (P = 0.66) between FS-LASIK and SMILE. The survival rates were 83.7% in the FS-LASIK group and 88.1% in the SMILE group. Multivariate analysis by the Cox PH model revealed a similar probability of postoperative myopic regression with SMILE or FS-LASIK (P = 0.630). Predictors of myopic regression included preoperative higher-order aberration root mean square with 3 mm pupil diameter (pre-HOA-RMS₃) (P = 0.004), anterior chamber depth (ACD) (P = 0.015), pre-subjective sphere (P = 0.016), corneal diameter (P = 0.016), optical zone (OZ) (P = 0.02), and predicted depth of ablation (DA) (P = 0.003).

CONCLUSION

SMILE and FS-LASIK had a similar risk of myopic regression for low to moderate myopia. Pre-HOA-RMS₃, ACD, pre-subjective sphere, corneal diameter, OZ, and predicted DA were predictors of myopic regression.

Factors Predicting the Need for Re-treatment After Laser Refractive Surgery in Patients With High Astigmatism: A Large Database Analysis

PURPOSE

To identify the potential risk factors that increase the likelihood of requiring re-treatment following refractive surgery in patients with high astigmatism (3.00 diopters or greater).

METHODS

This retrospective study included patients who underwent laser in situ keratomileusis (LASIK) or photorefractive keratectomy (PRK) between January 2005 and December 2019 at the Care-Vision Laser Centers, Tel-Aviv, Israel. Patients with high astigmatism (3.00 diopters or greater) were included and divided into two groups according to whether or not they underwent additional refractive surgery (re-treatment) during the study period.

RESULTS

Overall, 2,024 eyes (2,024 patients) were included in the final analysis of this study. In total, 3.1% of the eyes (n = 63) underwent re-treatment. Throughout the study period, there was a significant reduction in the 2-year annual re-treatment rates, with a decline from 7.0% for primary surgeries performed in 2005 to 0.0% for primary surgeries performed in 2017 (r =-0.65, P = .015). The re-treatment group had significantly older preoperative age. They were also more likely to be male and have preoperative against-the-rule astigmatism and preoperative mixed astigmatism. Binary logistic regression analysis demonstrated that preoperative age, male gender, mixed astigmatism, and earlier year of surgery were all associated with higher re-treatment rates.

CONCLUSIONS

The following factors are associated with higher rates of re-treatment in patients with high astigmatism: older preoperative age, male gender, and mixed astigmatism. These factors may be incorporated into nomograms to reduce future re-treatment rates in this population. [J Refract Surg. 2021;37(6):366-371.].

Advantages of Small Incision Lenticule Extraction (SMILE) for Mass Eye and Ear Special Issue

This review summarizes the advantages of Small-incision lenticule extraction (SMILE), including improved patient intraoperative experience, improved postoperative ocular surface, low incidence of regression, low re-treatment rates, and advantageous biomechanical corneal stability. Visual and refractive outcomes are similar to those achieved with LASIK, notably in large population studies. Since the inception of SMILE almost 10 years ago, the procedure has been rapidly growing in popularity. With the implementation of the novel SMILE technology in their practice, refractive surgeons generate excitement and potential for expanding the refractive market. Other parts of the world, including Asia, Europe, and Russia, SMILE has become the most popular refractive procedure performed. It is speculated that as SMILE continues to grow in popularity in the US since FDA approval in 2016 and more refractive surgeons implement this technology into their practice, it will drive an increase in the refractive market similar to what is seen in other countries.

Predictors affecting myopic regression in - 6.0D to - 10.0D myopia after laser-assisted subepithelial keratomileusis and laser in situ keratomileusis flap creation with femtosecond laser-assisted or mechanical microkeratome-assisted

PURPOSE

To investigate the predictive factors of postoperative myopic regression among subjects who have undergone laser-assisted subepithelial keratomileusis (LASEK), laser-assisted in situ keratomileusis (LASIK) flap created with a mechanical microkeratome (MM), and LASIK flap created with a femtosecond laser (FS). All recruited patients had a manifest spherical equivalence (SE) from - 6.0D to - 10.0D myopia.

METHODS

This retrospective, observational case series study analyzed outcomes of refraction at 1 day, 1 week, and 1, 3, 6, and 12 months postoperatively. Predictors affecting myopic regression and other covariates were estimated with the Cox proportional hazards model for the three types of surgeries.

RESULTS

The study enrolled 496 eyes in the LASEK group, 1054 eyes in the FS-LASIK group, and 910 eyes in the MM-LASIK group. At 12 months, from - 6.0D to - 10.0D myopia showed that the survival rates (no myopic regression) were 52.19%, 59.12%, and 58.79% in the MM-LASIK, FS-LASIK, and LASEK groups, respectively. Risk factors for myopic regression included thicker postoperative central corneal thickness (P ≦ 0.01), older age (P ≦ 0.01), aspherical ablation (P = 0.02), and larger transitional zone (TZ) (P = 0.03). Steeper corneal curvature (K_max) (P = 0.01), thicker preoperative central corneal thickness (P < 0.01), smaller preoperative myopia (P < 0.01), longer duration of myopia (P = 0.02), with contact lens (P < 0.01), and larger optical zone (OZ) (P = 0.02) were protective factors. Among the three groups, the MM-LASIK had the highest risk of postoperative myopic regression (P < 0.01).

CONCLUSIONS

The MM-LASIK group experienced the highest myopic regression, followed by the FS-LASIK and LASEK groups. Older age, aspheric ablation used, thicker postoperative central corneal thickness, and enlarging TZ contribute to myopic regression; steeper preoperative corneal curvature (K_max), longer duration of myopia, with contact lens, thicker preoperative central corneal thickness, lower manifest refraction SE, and enlarging OZ prevent postoperative myopic regression in myopia from - 6.0D to - 10.0D.

Myopic laser in situ keratomileusis retreatment: Incidence and associations

PURPOSE

To determine the factors associated with retreatment after laser in situ keratomileusis (LASIK) for myopic eyes in the modern LASIK era.

SETTING

Care-Vision Laser Centers, Tel-Aviv, Israel.

DESIGN

Retrospective cohort study.

METHODS

All cases of myopic LASIK performed between January 2005 and December 2012 were analyzed according to whether they had retreatment refractive surgery.

RESULT

The study evaluated 9177 right eyes in 9177 consecutive LASIK cases. The mean preoperative subjective spherical equivalent and astigmatism were -3.30 diopters (D) ± 1.53 (SD) (range -0.50 to -12.00 D) and 0.69 ± 0.94 D (range 0.00 to 6.00 D), respectively. Of the eyes, 165 (1.80%) had at least 1 retreatment. Over the course of the study, the 2-year retreatment rate decreased from 2.58% to 0.38% (P < .001). Multiple binary logistic regression analysis showed that older age (odds ratio [OR], 1.03; P = .007), higher astigmatism (OR, 1.23; P = .008), sphere (OR, 1.15; P = .026), and mean keratometric power (OR, 1.13; P = .036) significantly increased the odds for retreatment. A larger optical zone ablation (7.0 mm) significantly decreased the odds for retreatment (OR, 0.10; P = .022). Significant cutoffs associated with retreatments were age greater than 50 years, astigmatism more than 1.5 D, and sphere more than 2.0 D.

CONCLUSIONS

Older age and higher preoperative astigmatism, sphere, and corneal steepness were associated with myopic LASIK retreatment. Larger optical ablation zones might decrease retreatment rates.

FINANCIAL DISCLOSURE

None of the authors has a financial or proprietary interest in any material or method mentioned.

Risk Factors for Re-treatment Following Hyperopic LASIK

PURPOSE

To determine the risk factors for re-treatment following LASIK in hyperopic eyes.

METHODS

In this retrospective study, consecutive hyperopic eyes underwent LASIK at the Care Vision Laser Centers, Tel-Aviv, Israel, between January 2000 and October 2014. Patients were divided into two groups according to whether or not they underwent additional refractive surgery (re-treatment). Logistic regression was performed to determine predictors of re-treatment.

RESULTS

Overall, 1,776 eyes of 888 patients were included, of which 82 (4.6%) needed re-treatment. Eyes that underwent re-treatment were of older age (49.1 ± 7.5 vs 46.9 ± 10.3 years, P = .01), had better preoperative CDVA (1.0 ± 0.14 vs 0.95 ± 0.15 decimal, P = .001), were treated more often with the Allegretto EX200 (Alcon Laboratories, Inc., Fort Worth, TX) as opposed to the EX-500 (90.2% vs 63.7%, P < .001), and were treated with a Moria M2-90 microkeratome (Moria S.A., Antony, France) as opposed to Moria SBK-90 (66.7% vs 36.4%, P < .001). Multiple logistic regresison analysis demonstrated that treatment with Allegretto EX200 (odds ratio: 2.67, P = .04), and Moria M2-90 microkeratome (odds ratio: 2.23, P = .04) and older age (odds ratio: 1.03, P = .03) were significant risk factors for re-treatment.

CONCLUSIONS

Factors associated with a higher risk of re-treatment following hyperopic LASIK include type of laser, type of microkeratome used, and older age. Identifying such factors may aid in reducing future retreatment rates in hyperopic LASIK. [J Refract Surg. 2018;34(5):316-320.].

Enhancement after Small-Incision Lenticule Extraction: Incidence, Risk Factors, and Outcomes

PURPOSE

To report the incidence, risk factors, and outcomes of enhancement after small-incision lenticule extraction (SMILE).

DESIGN

Retrospective cohort study.

PARTICIPANTS

Five hundred twenty-four eyes of 307 patients who underwent SMILE at Singapore National Eye Center between February 2012 and March 2016.

METHODS

The data collected included patient age at primary SMILE, gender, race, preoperative and postoperative manifest refraction spherical equivalent (MRSE), preoperative and postoperative uncorrected distance visual acuity and corrected distance visual acuity, the occurrence of suction loss during the procedure, and the need for enhancement. All enhancements were carried out by performing an alcohol-assisted photorefractive keratectomy (PRK) procedure with application of mitomycin C (MMC).

MAIN OUTCOME MEASURES

Incidence, prevalence, preoperative and intraoperative risk factors for enhancement, and outcomes after enhancement.

RESULTS

The prevalence of enhancement was 2.7%, and 71.4% eyes had enhancement within 1 year of primary SMILE. The incidence of enhancement was 2.1% and 2.9% at 1 and 2 years, respectively. Age older than 35 years, preoperative MRSE more than -6.00 diopters (D), preoperative myopia more than 6.00 D, preoperative astigmatism more than 3.00 D, and intraoperative suction loss were significant risk factors for enhancement after SMILE after adjusting for all other covariates (odds ratios, 5.58, 4.80, 1.41, 3.06, and 2.14, respectively; P = 0.004, 0.021, 0.022, 0.002, and 0.020, respectively). In the patients who underwent bilateral SMILE, the first-operated eye had a marginal trend toward significance for enhancement (P = 0.054). There was no gender or racial difference. In the 14 eyes requiring enhancement, the uncorrected distance visual acuity before enhancement ranged from 20/80 to 20/25, and the mean attempted enhancement spherical equivalent was -0.50±0.86 D. The uncorrected distance visual acuity improved in most patients (92.9%) after enhancement.

CONCLUSIONS

The 2-year incidence of enhancement after SMILE was 2.9%. Risk factors associated with enhancement included older age at SMILE procedure, greater preoperative MRSE, greater preoperative myopia, greater preoperative astigmatism, and the occurrence of intraoperative suction loss. Clinical outcomes of using PRK with application of MMC for enhancement were good.

Photorefractive Keratectomy for Residual Myopia after Myopic Laser In Situ Keratomileusis

Purpose. To evaluate the safety, efficacy, and predictability of photorefractive keratectomy (PRK) on the corneal flap for correction of residual myopia following myopic laser in situ keratomileusis (LASIK). Patients and Methods. A retrospective study on eyes retreated by PRK on the corneal flap for residual myopia after LASIK. All eyes had no enough stroma after LASIK sufficient for LASIK enhancement. Data included spherical equivalent (SE), uncorrected and best corrected visual acuity (UCVA and BCVA), central pachymetry, corneal higher order aberrations (HOAs), corneal hysteresis (CH), corneal resistance factor (CRF), and corneal haze. Results. The study included 64 eyes. Before PRK, the mean central pachymetry was 400.21 ± 7.8 μm, the mean SE was -1.74 ± 0.51 D, and the mean UCVA and BCVA were 0.35 ± 0.18 and 0.91 ± 0.07, respectively. 12 months postoperatively, the mean central corneal thickness was 382.41 ± 2.61 μm, the mean SE was -0.18 ± 0.32 D (P < 0.01), and the mean UCVA and BCVA were 0.78 ± 0.14 (P = 0.01) and 0.92 ± 0.13 (P > 0.5), respectively. The safety index was 1.01 and the efficacy index was 0.86. No significant change was observed in corneal HOAs. Conclusions. Residual myopia less than 3 D after LASIK could be safely and effectively treated by PRK and mitomycin C with a high predictability. This prevents postoperative ectasia and avoids the flap related complications but has no significant effect on HOAs.

Factors Predicting the Need for Retreatment After Laser Refractive Surgery

PURPOSE

To identify the potential risk factors that increase the likelihood of requiring retreatment after refractive surgery.

METHODS

This retrospective study included patients who underwent laser in situ keratomileusis or photorefractive keratectomy between January 2005 and December 2012 at the Care-Vision Laser Centers, Tel-Aviv, Israel. Patients were divided into 2 groups according to whether they underwent additional refractive surgery (retreatment) during the study period.

RESULTS

Overall, 41,504 eyes (n = 21,313) were included in the final analysis of this study. Throughout the study period, there was a significant reduction in the 2-year annual retreatment rates with a decline from 4.52% for primary surgeries done in 2005 to 0.18% for surgeries performed in 2012 (quadratic R = 0.96, P < 0.001). The retreatment group had significantly higher preoperative age, maximum keratometric power, sphere, cylinder, and better best-corrected visual acuity. They were more likely to have preoperative hyperopia, photorefractive keratectomy as opposed to laser in situ keratomileusis, intraoperative higher humidity conditions and lower temperature, and higher ablation depths. Significant differences in retreatment rates were found between the 5 high-volume surgeons (>1500 procedures performed) ranging from 0.48 to 3.14% (P < 0.0001). Multiple logistic regression analysis demonstrated that age, astigmatism, hyperopia, temperature, and surgeon's experience all significantly affected the need for retreatment.

CONCLUSIONS

The following factors significantly increase the need for refractive retreatment: older preoperative age, higher degrees of astigmatism, hyperopia, colder operating room temperature, and less surgeon experience. Some of these factors may be incorporated into nomograms to reduce future retreatment rates.

Wavefront-guided retreatment after primary wavefront-guided laser in situ keratomileusis in myopes and hyperopes: long-term follow-up

PURPOSE

To assess the long-term safety, predictability, and efficacy of wavefront-guided laser in situ keratomileusis (LASIK) retreatment in myopes and hyperopes following primary wavefront-guided LASIK.

DESIGN

Retrospective nonrandomized case series.

METHODS

Wavefront-guided retreatment was performed by a single surgeon (D.G.). A cohort of 63 eyes of 41 patients were studied, investigating refractive outcome, uncorrected visual acuity (UCVA), and best-corrected visual acuity before and after wavefront-guided LASIK retreatment.

RESULTS

The mean spherical equivalent (MSE) prior to primary LASIK in the myopic group (46 eyes) was -5.4 +/- 2.5 diopters (D) (range, -1 to -11.25 D). After the final retreatment the MSE was -0.08 +/- 0.45 D (range, +1.25 to -1.25) with 82.6% achieving +/-0.5 D and 95.6% +/-1 D of emmetropia. The initial MSE in the hyperopic group (17 eyes) was +1.91 +/- 1.13 D (range, +0.25 to +5.73 D). After the final retreatment the MSE was +0.23 +/- 0.43 D (range, -0.5 to +1.25) with 88.2% achieving +/-0.5 D and 100% +/-1 D of emmetropia. Logarithm of the minimal angle of resolution UCVA was 0.22 +/- 0.21 prior to primary LASIK and -0.06 +/- 0.13 after final retreatment for myopes and 0.14 +/- 0.15 prior to primary LASIK and 0.06 +/- 0.16 after final retreatment for hyperopes. The mean follow-up time after LASIK enhancement was 17.75 months in the myopic and 14.6 months in the hyperopic group.

CONCLUSION

Our results suggest that wavefront-guided retreatment following initial wavefront-guided treatment in myopes and hyperopes has favorable outcome with respect to safety, predictability, and efficacy.

Incidence, outcomes, and risk factors for retreatment after wavefront-optimized ablations with PRK and LASIK

PURPOSE

To analyze and compare retreatment rates after wavefront-optimized photorefractive keratectomy (PRK) and LASIK and determine risk factors for retreatment.

METHODS

A retrospective chart review was performed to identify patients undergoing PRK or LASIK with the wavefront-optimized WaveLight platform from January 2005 through December 2006 targeted for a piano outcome and to determine the rate and risk factors for retreatment surgery in this population.

RESULTS

Eight hundred fifty-five eyes were analyzed, including 70 (8.2%) eyes with hyperopic refractions and 785 (91.8%) eyes with myopic refractions. After initial treatment, 72% of eyes were 20/20 or better and 99.5% were 20/40 or better. To improve uncorrected visual acuity, 54 (6.3%) eyes had retreatments performed. No significant differences in retreatment rates were noted based on age (P = .15), sex (P = .8), eye (P = .3), PRK versus LASIK (P = 1.0), room temperature (P = .1) or humidity (P = .9), and no correlation between retreatment rate and month or season of primary surgery (P = .4). There was no correlation between degree of myopia and retreatment rate. Eyes were significantly more likely to undergo retreatment if they were hyperopic (12.8% vs 6.0%, P = .006) or had astigmatism > or = 1.00 diopter (D) (9.1% vs 5.3%, P = .04).

CONCLUSIONS

Retreatment rate was 6.3% with the WaveLight ALLEGRETTO WAVE excimer laser. This rate was not influenced by age, sex, corneal characteristics, or environmental factors. Eyes with hyperopic refractions or astigmatism > or = 1.00 D were more likely to undergo retreatment.

LASIK in the presbyopic age group: safety, efficacy, and predictability in 40- to 69-year-old patients

OBJECTIVE

To report the safety, efficacy, and predictability of LASIK in a presbyopic population and to examine possible differences between age groups.

DESIGN

Retrospective, descriptive, comparative consecutive case series.

PARTICIPANTS

Seven hundred ten eyes of 424 patients between 40 and 69 years of age who underwent LASIK by the same surgeon between January 1999 and September 2005. Patients had manifest refractive spherical errors ranging from -10.5 to +6 diopters (D) and cylinder of up to 2.50 D.

METHODS

LASIK was performed with IntraLase femtosecond laser or Hansatome microkeratomes and VISX Star (S4 or S2; VISX Inc., Santa Clara, CA) or Baush & Lomb Technolas 217z (Zyoptix or PlanoScan; Bausch & Lomb, Claremont, CA) excimer lasers. There were 511 myopic eyes (spherical equivalent [SE], -5.03+/-2.02 D) and 199 hyperopic eyes (SE, +2.21+/-1.21 D). Patients were divided into 3 groups: group 1 (40 to 49 years old; n = 359 eyes), group 2 (50 to 59 years old; n = 293 eyes), and group 3 (60 to 69 years old; n = 58 eyes).

MAIN OUTCOME MEASURES

Uncorrected visual acuity (UCVA) and best spectacle-corrected visual acuity (BSCVA), retreatment rates, safety, efficacy, and predictability.

RESULTS

The mean age of patients in groups 1, 2, and 3 was 45, 53, and 63 years, respectively. With increasing age, there was a trend toward higher retreatment rates and more myopic end points. Safety, efficacy, and predictability were comparable between all groups. At the final follow-up (mean+/-standard deviation, 10.4+/-7.4 months), 80% to 100% of eyes had 20/30 or better UCVA and 81% to 90% were within +/-1.00 D. No eyes lost more than 2 lines of BSCVA, and only 9 eyes (1.3%) lost 2 lines. Subgroup analysis of eyes with a follow-up of 12 months or more was performed. The results were compared with those with shorter follow-up. Both subgroups had comparable outcomes; the duration of follow-up did not affect the visual outcomes.

CONCLUSIONS

Despite a trend toward worse final BSCVA and higher retreatment rates in older patients, a greater risk of visual loss after LASIK was not observed. LASIK for myopia and hyperopia has reasonable safety, efficacy, and predictability profiles in the 40- to 69-year-old presbyopic population.

Role of flap thickness in laser in situ keratomileusis enhancement for refractive undercorrection

PURPOSE

To determine which preoperative and/or perioperative factors determine the need for an enhancement for refractive undercorrection in laser in situ keratomileusis (LASIK) for spherical or spherocylindrical myopia.

SETTING

Clinical refractive surgery outpatient facility.

METHODS

In this nested case-control study within a retrospective cohort, 3850 of the 9777 eyes operated on between January 1996 and August 2005 who met the selection criteria were studied. Only patients whose refractive goal was plano were included. Control eyes were those whose latest spherical equivalent (SE) refraction was within +/-0.37 diopters (D) of emmetropia. Cases were defined as enhancements for undercorrection with an SE refraction worse than or equal to -0.50 D performed less than 6 months following the primary surgery.

RESULTS

Factors associated with enhancement included increasing patient age (odds ratio [OR] = 1.048, P<.001), decreasing follow-up time (OR = 0.994, P<.001), increasing minus laser sphere (OR = 0.700, P<.001) and cylinder settings (OR = 0.718, P<.001), female sex (OR = 1.112, P = .046), and corneal toricity (OR = 1.237, P = .012). The Summit laser had a significant risk for enhancement (OR = 1.726, P<.001) compared with the Visx laser, whereas the Wavelight Allegretto had a lowered risk (OR = 0.630, P = .049). Enhancement risk with the Autonomous was no different from that with the Visx (OR = 1.120, P = .342). Increasing flap thickness (OR = 1.009, P<.001) was more strongly associated with enhancement risk than residual stromal bed thickness.

CONCLUSIONS

After controlling for patient age, time to follow-up or surgery, corneal cylinder, sphere and cylinder laser settings, laser manufacturer, patient sex, and corneal thickness, increasing flap thickness was found to be a more important predictor of enhancement for refractive undercorrection than residual stromal thickness.

Visual acuities and manifest refractions prior to LASIK retreatments

PURPOSE

To demonstrate that patients undergoing LASIK retreatments generally have good uncorrected vision and small refractive errors prior to retreatment surgery.

METHODS

A list was generated of all refractive surgery retreatments performed in our four laser centers from August 2003 to July 2004. From this list, a total of 100 patient charts were randomly chosen. Only eyes that had full distance correction with LASIK as the primary surgery were included. The last uncorrected visual acuity (UCVA) and manifest refraction spherical equivalent (MRSE) prior to retreatment were recorded.

RESULTS

For a total of 109 eyes studied, the average UCVA prior to retreatment was 20/36. Eighty-one percent (88/109) of the retreated eyes were already seeing > or = 20/40. The average MRSE prior to retreatment was -0.43 +/- 0.98 D.

CONCLUSIONS

The majority of patients receiving LASIK retreatments have relatively good uncorrected vision and minimal refractive errors prior to retreatment.

Complications and visual outcome of LASIK performed by anterior segment fellows vs experienced faculty supervisors

PURPOSE

To determine the complication rates and visual outcome of laser-assisted in situ keratomileusis (LASIK) that is performed by anterior segment fellows and to compare their results with the results of their experienced faculty supervisors.

DESIGN

A single-center, retrospective, interventional, nonrandomized, comparative case series.

METHODS

Chart review of the initial 50 LASIK procedures that were performed by each of 10 anterior segment fellows and the first 50 inclusion criteria-matched, contemporaneously performed cases of four faculty members at the King Khaled Eye Specialist Hospital between March and December 2003.

RESULTS

There were no statistically significant differences between fellow and faculty cases with respect to complication rates and final visual outcomes. The fellows were significantly more likely to experience microkeratome-related flap complications during their first 25 cases, compared with their second 25 cases (4.8% vs 1.2%; P = .03). Fellows were significantly more likely to perform enhancements (8.0% vs 2.0%; P = .0002), after which the eyes in their group were more likely to be within 1 diopter of the intended refractive target than those in the faculty group (96.0% vs 91.0%; P = .01). Although not statistically significant, eyes in the fellow group were four-fold (2.0% vs 0.5%) more likely to lose two or more lines of best spectacle corrected visual acuity than those in the faculty group.

CONCLUSION

To minimize the adverse impact of complications during the learning curve of novice LASIK surgeons, the introduction of this procedure in a well-structured, supervised setting (such as a subspecialty fellowship training program) is recommended.