Long-Term Followup of Laser In Situ Keratomileusis for Hyperopia Using a 213 nm Wavelength Solid-State Laser

One-Year Results of Photorefractive Keratectomy for Myopia and Compound Myopic Astigmatism with 210 nm Wavelength All Solid-State Laser for Refractive Surgery

BACKGROUND

To examine the 12-month clinical and refractive outcomes of PRK performed with a UV all-solid-state laser.

METHODS

The study included healthy patients with myopia and/or compound myopic astigmatism enrolled for refractive surgery and treated with PRK using a 210 nm wavelength, 2 kHz repetition rate, UV all-solid-state laser (LaserSoft, Katana Technologies GmbH, Kleinmachnow, Germany). All subjects were examined at baseline and after 1, 3, 6, and 12 months after the treatment with a slit lamp, refraction, visual acuity assessment (logMAR chart), tonometry, ophthalmoscopy, and corneal tomography with a Scheimpflug camera. The outcome measures considered were uncorrected (UDVA) and corrected (CDVA) distance visual acuities, refraction, central corneal thickness, and transparency. The efficacy, safety, predictability, and stability were determined.

RESULTS

The study included 34 eyes of 19 patients. The mean UDVA changed from 1.20 ± 0.43 to -0.05 ± 0.10 logMAR at 12 months, and the mean CDVA changed from -0.03 ± 0.06 to -0.06 ± 0.09 logMAR, respectively. The mean spherical equivalent (SE) changed from -4.90 ± 2.12 D to -0.01 ± 0.40 D and was within ±0.50 D of the intended correction in 91% of eyes and within ±1.00 D in 97% of eyes at 12 months. No eyes lost lines of visual acuity, and 64% of eyes gained one or more lines.

CONCLUSIONS

PRK with the 210 nm wavelength, 2 kHz repetition rate, all-solid-state laser LaserSoft system proved to have good visual, refractive, and clinical outcomes after the follow-up at 12 months. The emerging gas-free, solid-state technology might be considered a valid alternative for the gas operating lasers for corneal refractive surgery.

Laser-Assisted In Situ Keratomileusis (LASIK) Enhancement for Residual Refractive Error after Primary LASIK

Background: To evaluate the safety, efficacy, and predictability of laser-assisted in situ keratomileusis (LASIK) enhancement after primary LASIK and compare to Food and Drug Administration (FDA) criteria. Methods: Patients who underwent LASIK enhancement after primary LASIK between 2002 and 2019 were compared to those who underwent LASIK without retreatment. Patient demographics, preoperative characteristics, visual outcomes, and postoperative complications were compared between groups. Epithelial ingrowth (EI) development was stratified based on duration between primary and secondary procedures. Results: We compared 901 eyes with LASIK enhancement to 1127 eyes without retreatment. Age, sex, surgical eye, sphere, cylinder, and spherical equivalent (SE) were significantly different between groups (p < 0.05). At 12 months post-enhancement, 86% of the eyes had an uncorrected distance visual acuity of 20/20 or better and 93% of eyes were within ±0.50 D of the target. Development of EI (6.1%) demonstrated an odds ratio of 16.3 in the long-term compared to the short-term (95% CI: 5.9 to 45.18; p < 0.0001). Conclusions: Older age at primary LASIK, female sex, right eye, and larger sphere, cylinder and SE were risk factors for enhancement. Risk of EI significantly increased when duration between primary and enhancement procedures exceeded five years. LASIK enhancements produce favorable outcomes and meet FDA benchmarks for safety, efficacy, and predictability.

One-year follow-up of patients with hyperopia undergoing photorefractive keratectomy with Allegretto WaveLight Eye Q 400

This study aimed to examine the effectiveness of photorefractive keratectomy (PRK) in treating patients with cycloplegic hyperopia from +1.00 to +7.00 diopter using Allegretto wave Eye Q 400. This study was conducted on 25 patients with cycloplegic astigmatism ≤1 diopter and cycloplegic hyperopia between +1.00 and +7.00 diopters in 47 eyes, who successively entered into the study within 6 months and underwent PRK. Prior to PRK surgery, all the patients were examined for cycloplegic refraction (astigmatism and hyperopia), slit lamp, keratometry, fundus, and best-corrected (BCVA) and uncorrected visual acuity (UCVA) testing. These examinations were repeated after 1 week, 1 month, 3 months, 6 months, and 1 year postoperatively. The mean preop UCVA of patients was 0.76±0.28 (ranging from 0.00 to 1.3), which reached 0.19±0.22 (ranging from 0.00 to 0.78) one year after the surgery (P=0.000). There was a significant correlation between increasing astigmatism and preop cycloplegic hyperopia >5 diopters (P=0.000), corneal ring haziness at 12^th months (P=0.000), and 12 months cycloplegic residual hyperopia ≥2.00 diopters (P=0.000). 53.2% of the eyes (with a mean grade of 2.34) were detected with corneal ring haziness at 12^th months, which was significantly correlated with 12 months residual cycloplegic hyperopia of ≥2.00 diopters (P: 0.000) and cycloplegic sphere above 5 diopters (P=0.006). Although the use of photorefractive keratectomy (PRK) with Allegretto Eye Q 400 is associated with a decrease in the mean cycloplegic and improved UCVA and BCVA, its use is not recommended in cases with preop cycloplegic hyperopia above 5 diopters due to the high rate of induction of astigmatism, corneal haziness, and regression of hyperopia.

Lasik as a Solution for High Hypermetropia

Aim:

To evaluate safety and efficacy of Laser in situ Keratomileusis (LASIK) procedure for the correction of high hypermetropia.

Methods:

Retrospective study of 160 patients (266 eyes) who underwent LASIK procedure for the correction of hypermetropia between +3.00 and +7.00 diopters(D) and cylinder up to 2.00D from January 2013 and August 2015. All ablations were performed with Wavelight Allegretto Eye-Q400Hzexcimer laser (Alcon, Forth Worth, TX, USA) with aberration free module and were centered on a corneal vertex. All flaps were made with Moria M2 (Moria, Antony, France) mechanical microkeratome (90μm head). Preoperative and postoperative uncorrected and corrected distant visual acuity (UDVA, CDVA), spherical equivalent (SE) and a berrometry for 5mm pupil were measured. Measurements were taken at 1 week, 1,3,6 and 12 months after the surgery. Wilcoxon Signed Ranks Test was used for statistical analysis.

Results:

Postoperative UDVA was lower than preoperative CDVA at 1 week(p=0.001), at 1 month there was no difference (p=0.099), and at 3,6 and 12 months UDVA was better (p<0.0001). Preoperative SE was 4.69±1.20D (+3.75 to +7.50D). At 1 week SE was 0.03±0.67D (-0.50 to +0.63D), while at 1 year regressed to 0.58±0.56D (+0.25 to +0.88D). Sphere shifted from negative values targeted in treatment planning to compensate for regression to positive values. There was significant difference in SE at every time point (p<0.0005). There was a significant increase in coma (p<0.0001), trefoil (p<0.0001, p=0.0006) and spherical aberration (p=0.022, p=0.0052) at 1 week and 1 month postoperatively, without change throughout the rest of follow up.

Conclusion:

LASIK for high hypermetropia showed satisfactory results in postoperative refraction with reasonable regression without significant loss of lines of visual acuity. However, more test are necessary to asses optical quality.

Stability of corneal topography and aberrometry after hyperopic laser in situ keratomileusis with a 500-Hz excimer laser platform: A 3-year follow-up study

PURPOSE

The aim of this study is to analyze the long-term stability of the corneal topography, the functional optical zone, and the refractive stability throughout 3 years following laser in situ keratomileusis surgery for hyperopia using a 500-Hz excimer laser system.

METHODS

This retrospective consecutive observational case series study comprised 66 eyes that underwent laser in situ keratomileusis to correct hyperopia with a postoperative follow-up of 3 years. Laser in situ keratomileusis procedures were performed using the SCHWIND Amaris 500-Hz excimer laser. Main outcomes measured were stability of the functional optical zone at corneal topography and corneal aberrometry.

RESULTS

Statistically significant differences were found in simulated keratometry (K2 (steep meridian) and Km (mean keratometry)) between 3 and 36 months postoperatively (p ⩽ 0.01); these differences disappeared at 12 and 36 months (p ⩾ 0.18). No statistically significant changes were observed in the horizontal and vertical diameter of the functional optical zone throughout the whole follow-up (p ⩾ 0.07). A statistically significant difference was found in the spherical aberration between 3 and 36 months (p = 0.02); this difference disappeared when compared between 12 and 36 months (p = 0.72). Statistically significant correlations were detected between the vertical functional optical zone and coma root mean square (r = -0.510, p < 0.01) and between the vertical functional optical zone and spherical aberration (r = 0.441, p = 0.02) 36 months after surgery.

CONCLUSION

Following 3 years of hyperopic laser in situ keratomileusis with a 500-Hz Amaris excimer laser, keratometry, functional optical zone, and corneal aberrations remain stable from 1 year after surgery. Topographical regression is not observed in hyperopic laser in situ keratomileusis with this excimer laser technology from 1 year after surgery.

Femtosecond Laser-Assisted LASIK With and Without the Adjuvant Use of Mitomycin C to Correct Hyperopia

PURPOSE

To compare the visual and refractive results of femtosecond laser-assisted LASIK (FS-LASIK) with and without the adjuvant use of mitomycin C (MMC) to correct hyperopia.

METHODS

A total of 152 consecutive hyperopic eyes were included in this retrospective, observational cohort study, comparing 76 eyes treated with FS-LASIK + MMC with 76 age- and refraction-matched eyes treated with FS-LASIK without MMC. Visual and refractive results were evaluated 1 day, 1 week, and 1, 3, 6, and 15 months postoperatively.

RESULTS

Preoperative mean spherical equivalent was +3.27 diopters (D) versus +3.50 D in the MMC and no MMC groups, respectively (P > .05). Three months postoperatively, uncorrected distance visual acuity was significantly better in the MMC group (0.93 ± 0.2) than in the no MMC group (0.87 ± 0.2) (P = .01). The residual spherical equivalent was significantly lower in the MMC group (+0.18 ± 0.40 D) than in the no MMC group (+0.42 ± 0.50 D) (P = .01). Fifteen months postoperatively, including re-treated eyes, no significant differences were found in uncorrected distance visual acuity, corrected distance visual acuity, and residual refraction. Slightly better outcomes were found in the MMC group in terms of efficacy, safety, and predictability; however, these small differences were not statistically significant. The incidence of re-treatments during the 15-month follow-up was significantly lower in the MMC group than in the no MMC group (6.6% vs 10.5%, respectively) (P = .01).

CONCLUSIONS

FS-LASIK with or without the intraoperative use of MMC is safe and effective to correct hyperopia. However, slightly better refractive outcomes and a lower incidence of re-treatments were observed when intraoperative MMC was used, at least in a 15-month follow-up. [J Refract Surg. 2018;34(1):23-28.].

The Characteristics of Excimer Laser Refractive Surgery Candidates

PURPOSE

To determine the demographic and refractive characteristics of excimer laser refractive surgery candidates in Iran.

METHODS

This was a cross-sectional study between 2010 and 2014. All information was collected from 28 centers randomly selected from 12 provinces. Then, for each season of the year, one week was chosen through simple random selection, and within each week, 3 days were again chosen randomly. All excimer laser surgical procedures performed during these 3 days were identified by training staff, and data were extracted from patient charts.

RESULTS

A total of 14,569 charts were reviewed; 67.5% of the subjects were female and the rest were male. Of the total surgeries, 18.6% had been done in 2010 which reached to 19.1% in 2014. The mean age of people receiving refractive surgery showed an upward trend (P<0.001) and female patients were significantly younger than male patients (P<0.001). The 25 to 39 years age group received the highest number of surgeries (31.9% of the total) and there was a significant association with gender (P<0.001). The most common refractive error was compound myopic astigmatism with a prevalence of 79.3%. In 2010, 33.3% of the performed surgeries were covered by insurance policies, and this decreased to 30.2% in 2014 (P<0.001).

CONCLUSION

Women with compound myopic astigmatism in the age range of 25 and 35 years are the most frequent users of excimer laser refractive surgery. Less than one-third of laser refractive surgeries are covered by insurance policies. Therefore, proper planning for improving services to this group must be given priority.

Laser in Situ Keratomileusis for High Hyperopia with Corneal Vertex Centration and Asymmetric Offset

Purpose

To investigate refractive outcomes and induction of corneal higher order aberrations (HOA) in eyes that underwent laser-assisted in situ keratomileusis (LASIK) for high hyperopia correction using an aberration neutral profile with corneal vertex centration and asymmetric offset.

Methods

A total of 24 consecutive patients (38 eyes) who underwent LASIK by one surgeon using AMARIS 750S excimer laser and a Carriazo-Pendular microkeratome for flap creation were retrospectively analyzed. Eyes targeted for plano and with correction in the maximum hyperopic meridian strictly higher than +4D were included in the retrospective analysis. Patients were reviewed at 1, 3, and 6 months postoperatively. Postoperative monocular corrected distance visual acuity (CDVA) and uncorrected distance visual acuity (UDVA), manifest refraction, and corneal wavefront aberrations were compared with respective preoperative metrics.

Results

Mean preoperative spherical equivalent and refractive astigmatism was +4.07 ± 0.90 D and 1.37 ± 1.26 D, respectively, reducing to +0.28 ± 0.58D (p<0.0001) and 0.49 ± 0.47 D (p = 0.0001) at the last postoperative visit. Six months postoperatively, 78% of eyes achieved a UDVA of 20/25 or better. No eye lost more than 2 Snellen lines of CDVA at any follow-up. There was a statistically significant induction of vertical trefoil (+0.104 ± 0.299 µm, p<0.05), vertical coma (-0.181 ± 0.463 µm, p<0.01), horizontal coma (+0.198 ± 0.663 µm, p<0.05), spherical aberration (-0.324 ± 0.281 µm, p<0.0001), secondary vertical trefoil (+0.018 ± 0.044 µm, p<0.01), and secondary horizontal coma (+0.026 ± 0.083 µm, p<0.05)

Conclusions

Laser-assisted in situ keratomileusis for high hyperopia using corneal vertex centration with asymmetric offset results in significant improvement in refraction and visual acuity although affected by significant induction of some higher order aberrations.

Accuracy and stability of hyperopic treatments

PURPOSE OF REVIEW

Treatment of hyperopia presents greater challenges than treatment of myopia for multiple reasons, including the fact that hyperopia tends to progress with age and becomes more symptomatic with the loss of accommodation.

RECENT FINDINGS

Despite these issues, surgeons have multiple options to treat hyperopia successfully. Modern laser vision correction has high success rates for most patients and performs acceptably in the presence of high hyperopia or high cylinder. Early studies combining excimer laser treatment with collagen cross-linking (CXL) suggest that this may improve refractive stability. Recent studies have also described femtosecond lenticule extraction and use of a solid-state laser in place of the excimer. In addition to cornea-based treatment, long-term studies of a hyperopic phakic intraocular lens have shown excellent visual outcomes and good safety. Cross-linking is increasingly being applied to the hyperopia that follows radial keratotomy.

SUMMARY

The established treatments for hyperopia continue to accumulate evidence supporting their safety and efficacy. The next step forward in treatment may arise from combining these treatments with CXL to stabilize the cornea long-term.

Photorefractive Keratectomy with Adjunctive Mitomycin C for Residual Error after Laser-Assisted In Situ Keratomileusis Using the Pulzar 213 nm Solid-State Laser: Early Results

Purpose. To evaluate the accuracy, efficacy, stability, and safety of photorefractive keratectomy (PRK) enhancement using the Pulzar 213 nm solid-state laser (SSL) with adjunctive Mitomycin C in eyes previously treated with laser assisted in situ keratomileusis (LASIK) with residual error of refraction. Methods. This is a prospective noncomparative case series of 16 eyes of 12 patients who underwent PRK for residual refractive error after primary LASIK. Mitomycin C 0.02% was used after the PRK to prevent haze formation. Outcomes measured were pre- and postoperative manifest refraction spherical equivalent (MRSE), uncorrected (UDVA) and best-corrected distance visual acuity (CDVA), and slit lamp evidence of corneal complications. Results. The mean UDVA improved from 20/70 preoperatively to 20/30 postoperatively. The average gain in lines for the UDVA was 2.38. After six months of followup, the postoperative MRSE within 0.50 D in 56% (9) of eyes and 94% (15) eyes were within 1.0 diopters of the intended correction. No eyes developed haze all throughout the study. Conclusion. PRK enhancement with adjunctive use of Mitomycin C for the correction of residual error of refraction after LASIK using the Pulzar 213 nm solid-state laser is an accurate, effective, and safe procedure.