Aleksandar Stojanovic

IntraLase Femtosecond Laser vs Mechanical Microkeratomes in LASIK for Myopia: A Systematic Review and Meta-analysis

PURPOSEnTo evaluate the safety, efficacy, and predictability of IntraLase (Abbott Medical Optics) femtosecond laser-assisted compared to microkeratome-assisted myopic LASIK.nnnMETHODSnA comprehensive literature search of Cochrane Library, PubMed, and EMBASE was conducted to identify relevant trials comparing LASIK with IntraLase femtosecond laser to LASIK with microkeratomes for the correction of myopia. Meta-analyses were performed on the primary outcomes (loss of ≥2 lines of corrected distance visual acuity [CDVA], uncorrected distance visual acuity [UDVA] 20/20 or better, manifest refraction spherical equivalent [MRSE] within ±0.50 diopters [D], final refractive SE, and astigmatism), and secondary outcomes (flap thickness predictability, changes in higher order aberrations [HOAs], and complications).nnnRESULTSnFifteen articles describing a total of 3679 eyes were identified. No significant differences were identified between the two groups in regards to a loss of ≥2 lines of CDVA (P=.44), patients achieving UDVA 20/20 or better (P=.24), final UDVA (P=.12), final mean refractive SE (P=.74), final astigmatism (P=.27), or changes in HOAs. The IntraLase group had more patients who were within ±0.50 D of target refraction (P=.05) compared to the microkeratome group, and flap thickness was more predictable in the IntraLase group (P<.0001). The microkeratome group had more epithelial defects (P=.04), whereas the IntraLase group had more cases of diffuse lamellar keratitis (P=.01).nnnCONCLUSIONSnAccording to the available data, LASIK with the IntraLase femtosecond laser offers no significant benefits over LASIK with microkeratomes in regards to safety and efficacy, but has potential advantages in predictability.

Topography-guided transepithelial surface ablation followed by corneal collagen cross-linking performed in a single combined procedure for the treatment of keratoconus and pellucid marginal degeneration.

PURPOSEnTo evaluate a combination of topography-guided custom ablation and corneal collagen cross-linking (CXL) in a single procedure for the treatment of keratectasia.nnnMETHODSnTwelve eyes of 12 patients with keratectasia were treated with topography-guided custom ablation and CXL. Topography-guided custom ablation was performed using a transepithelial technique with the iVIS Suite 1 kHz flying spot excimer laser. Collagen cross-linking was performed immediately after topography-guided custom ablation, according to standard protocol. Postoperative follow-up examinations were performed at 1, 3, 6, and 12 months. Uncorrected visual acuity (UCVA), best spectacle-corrected visual acuity (BSCVA), refractive change, corneal topography, and pachymetry were analyzed pre- and postoperatively.nnnRESULTSnMean UCVA increased from 20/1000 preoperatively to 20/125 12 months postoperatively. Mean BSCVA increased from 20/57 to 20/35, with no loss of lines of visual acuity. Mean astigmatism was reduced from 5.40+/-2.13 diopters (D) to 2.70+/-1.44 D, and keratometric asymmetry decreased from 6.38+/-1.02 D to 2.76+/-0.73 D. Only minor changes in posterior corneal surface elevation and stability of refraction were found, confirming that no progression of ectasia occurred during the observation time.nnnCONCLUSIONSnA combination of topography-guided custom ablation and CXL improved patients visual, refractive, and topography outcomes and halted the progression of keratectasia within the observation period of 12 months. This method may postpone or eliminate the need for corneal transplantation in suitable cases with keratectasia.

Correlation between ultraviolet radiation level and the incidence of late-onset corneal haze after photorefractive keratectomy

Purpose: To investigate the correlation between environmental changes in ultraviolet (UV) radiation levels and the incidence of late‐onset cornea haze (LOCH) after photorefractive keratectomy (PRK). Setting: SynsLaser Clinic, Tromsø, Norway. Methods: The study comprised 404 eyes that had myopic PRK and photoastigmatic refractive keratectomy from February 1996 through July 1998. The high latitude (70° N) of the observation site provided “natural laboratory” conditions to look at the occurrence of LOCH with high and low UV‐radiation levels, which occurred during summers and winters, respectively. The diagnostic criterion for LOCH was acute haze of grade ≥2 occurring between 4 and 12 months postoperatively. Results: The follow‐up ranged from 12 to 41 months. Of the 314 eyes that met the inclusion criteria, 11 developed LOCH when the environmental UV‐radiation level was high. No eye developed LOCH when the level was low. The correlation between a high level of environmental UV radiation and the occurrence of LOCH was statistically significant (P = .001). Conclusion: Environments with high UV‐radiation levels may increase the risk of LOCH after PRK in eyes with moderate to high myopia. Use of UV‐protective eyewear should be encouraged during the first year after PRK.

Meta-analysis of Clinical Outcomes Comparing Surface Ablation for Correction of Myopia With and Without 0.02% Mitomycin C

PURPOSEnTo evaluate the current clinical evidence of safety and efficacy of intraoperative topical application of 0.02% mitomycin C (MMC) used for up to 2 minutes after surface ablation for correction of myopia.nnnMETHODSnA comprehensive literature search was conducted of Cochrane Library, MEDLINE, and EMBASE to identify relevant trials comparing surface ablation for correction of myopia with and without MMC. A meta-analysis was performed on the results of the reports and statistical analysis was performed.nnnRESULTSnEleven clinical trials were identified with MMC used in 534 eyes and no MMC in 726 eyes. Surface ablations with MMC led to significantly less corneal haze in photorefractive keratectomy, whereas the results were comparable in laser epithelial keratomileusis (LASEK) and epithelial laser in situ keratomileusis (epi-LASIK). Although proportionately more eyes in the MMC group achieved uncorrected distance visual acuity 20/25 or better and less frequently lost ≥ 2 lines of corrected distance visual acuity, the difference was not statistically significant.nnnCONCLUSIONSnOur meta-analysis suggests that the topical intraoperative application of 0.02% MMC may reduce haze and improve visual acuity after surface ablation for correction of myopia. However, the advantage of using MMC in LASEK and epi-LASIK is unclear.

200 Hz flying-spot technology of the LaserSight LSX excimer laser in the treatment of myopic astigmatism: six and 12 month outcomes of laser in situ keratomileusis and photorefractive keratectomy

Purpose: To evaluate safety, efficacy, predictability, and stability in the treatment of myopic astigmatism with laser in situ keratomileusis (LASIK) and photorefractive keratectomy (PRK) using the 200 Hz flying‐spot technology of the LaserSight LSX excimer laser. Setting: SynsLaser Clinic, Tromsø, Norway. Methods: This retrospective study included 110 eyes treated with LASIK and 87 eyes treated with PRK that were available for evaluation at 6 and 12 months, respectively. The mean preoperative spherical equivalent (SE) was −5.35 diopters (D) ± 2.50 (SD) (range −1.13 to −11.88 D) in the LASIK eyes and −4.72 ± 2.82 D (range −1.00 to −15.50 D) in the PRK eyes. The treated cylinder was 4.00 D in both groups. Eleven (8.5%) LASIK eyes and 8 (7.4%) PRK eyes had secondary surgical procedures before 6 and 12 months, respectively, and were excluded when the 6 and 12 month outcomes were analyzed. Results: None of the eyes lost 2 or more lines of best spectacle‐corrected visual acuity. Seventy‐seven percent of the LASIK eyes and 78% of the PRK eyes achieved an uncorrected visual acuity of 20/20 or better; 98% in both groups achieved 20/40 or better. The SE was within ±0.5 D of the desired refraction in 83% of the LASIK eyes and 77% of the PRK eyes; it was within ±1.0 D in 97% and 98%, respectively. The cylinder correction had a mean magnitude of error of 0.04 ± 0.31 D (range −0.96 to +0.85 D) in the LASIK eyes and 0.02 ± 0.37 D (range −1.44 to +0.72 D) in the PRK eyes. Refractive stability was achieved at 1 month and beyond in the LASIK eyes and at 3 months and beyond in the PRK eyes. Conclusion: The outcomes of this study are comparable to those achieved with lasers that use small‐beam technology with a lower frequency, as well as with other types of delivery systems. They suggest that the 200 Hz technology used in the LaserSight LSX excimer laser is safe, effective, and predictable and that with LASIK and PRK the results are stable when treating low to moderate myopia and astigmatism up to 4.0 D.

Penetration of riboflavin and postoperative pain in corneal collagen crosslinking : Excimer laser superficial versus mechanical full-thickness epithelial removal

PURPOSE: To compare the severity of postoperative pain and the rate of penetration of riboflavin between eyes treated by corneal crosslinking (CXL) using excimer laser superficial epithelial removal and mechanical full‐thickness epithelial removal. SETTING: Departments of Ophthalmology, Ullevål University Hospital, Oslo, and University Hospital of Northern Norway, Tromsø, Norway. METHODS: Patients with corneal ectasia were treated with superficial corneal epithelial removal using the excimer laser programmed to 35 μm of phototherapeutic keratectomy (Group 1) or mechanical full‐thickness epithelial removal with a brush (Group 2). Pain was evaluated postoperatively by the patients subjective evaluation and need for analgesia. The duration of topical application of riboflavin to achieve stromal saturation was measured. RESULTS: Thirty eyes of 30 patients, 15 in each group, were treated. Postoperative pain was severe in 40.0% of patients in Group 1 and in no patient in Group 2 (P = .009) and moderate in 53.3% and 33.3%, respectively (no significant difference). The mean time to riboflavin saturation was 43.7 minutes ± 10.8 (SD) in Group 1 and 31.3 ± 3.0 minutes in Group 2 (P = .001). CONCLUSION: Superficial epithelial removal using the excimer laser resulted in more postoperative pain and the need for prolonged application of riboflavin to achieve corneal saturation.

Topography-Guided Transepithelial Surface Ablation in Treatment of Recurrent Epithelial Ingrowths

PURPOSEnTo describe a new, single-step, transepithelial and trans-LASIK flap topography-guided surface ablation technique in a case of recurrent epithelial ingrowth with visual disturbances caused by irregular astigmatism, scattering, and decreased corneal transparency after LASIK.nnnMETHODSnCustom ablation through both the epithelium and the LASIK flap performed by 1-kHz flying spot excimer laser was used to transform an irregular corneal surface into a regular aspheric surface and in the same continuous process to ablate the epithelial ingrowth causing the irregularity.nnnRESULTSnVisual rehabilitation was achieved, the corneal surface was regularized, and epithelial ingrowth was removed within the ablation.nnnCONCLUSIONSnThe transepithelial topography-guided surface ablation technique was safe and effective in this case of visually disturbing epithelial ingrowth after LASIK, and may also be applied to treat other types of flap/interface complications.

Comparison of Clinical Outcomes between ‘On-Flap’ and ‘Off-Flap’ Epi-LASIK for Myopia: A Meta-Analysis

Objective: To examine possible differences in clinical outcomes between off-flap and on-flap epipolis laser in situ keratomileusis (epi-LASIK) for myopia. Methods: Pertinent studies were selected by extensive searches. A total of 9 studies reporting on a total of 958 eyes were included in the present meta-analysis. Statistical analysis was performed using RevMan 5.0 software. Results: There were no significant differences in the final refractive spherical equivalent (p = 0.38), manifest refractive spherical equivalent within ±0.50 D of the target (p = 0.76), final uncorrected visual acuity (p = 0.90), loss of ≧1 line of best spectacle-corrected visual acuity (p = 0.99), and corneal haze at 3 months postoperatively (p = 0.96) or more than 6 months (p = 0.64). More patients felt severe pain in the on-flap group than in the off-flap group, although this finding was not statistically significant (p = 0.05). However, off-flap epi-LASIK had a better mean uncorrected visual acuity at 3 days (p = 0.04) and 5 days (p = 0.01), and faster re-epithelialization (p < 0.00001) after surgery. Conclusions: According to the available data, off-flap and on-flap epi-LASIK had equal visual and refractive outcomes for the treatment of myopia. Off-flap epi-LASIK had more rapid re-epithelialization and visual recovery compared to on-flap epi-LASIK.

Aspheric Micro-monovision LASIK in Correction of Presbyopia and Myopic Astigmatism: Early Clinical Outcomes in a Chinese Population

PURPOSEnTo analyze early clinical outcomes of aspheric micro-monovision LASIK for correction of presbyopia and myopia with or without astigmatism.nnnMETHODSnProspective, non-comparative case series of 80 eyes of 40 patients with a mean age of 43.4 ± 4.9 years (range: 38 to 63 years) treated bilaterally using an aspheric micro-monovision protocol. The target refraction was plano for the distance eye and between -0.75 and -2.25 diopters (D) for the near eye. Visual acuity, ocular aberrations, contrast sensitivity, corneal topography, amplitude of accommodation, binocular sensorial function, and satisfaction score questionnaires were evaluated at 3 months after surgery.nnnRESULTSnThree months after surgery, the mean spherical equivalent (SE) refraction in the distance eye was -0.08 ± 0.27 D, whereas the attempted and achieved SE in the near eye were -1.41 ± 0.28 and -1.32 ± 0.35 D, respectively. Ninety-three percent of eyes were within ±0.50 D of target correction of SE. The uncorrected distance visual acuity (UDVA) after surgery was -0.10 ± 0.06 logMAR (20/15.5), 0.22 ± 0.12 logMAR (20/34), and -0.11 ± 0.06 logMAR (20/15), for distance eyes, near eyes, and binocularly, respectively. Ninety-five percent of patients achieved simultaneously uncorrected distance visual acuity 0.0 logMAR (20/20) or better and uncorrected near visual acuity J2 (20/25) or better. Stability was achieved from 1 week of follow-up. The overall satisfaction score for surgery was 92 ± 6.nnnCONCLUSIONSnThe aspheric micro-monovision protocol provided a well-tolerated and effective means for treating myopic astigmatism and alleviating presbyopic symptoms simultaneously. [J Refract Surg. 2016;32(10):680-685.].