Anders Højslet Vestergaard

Small-incision lenticule extraction for moderate to high myopia: Predictability, safety, and patient satisfaction

PURPOSE: To present initial clinical experience with small‐incision lenticule extraction for the treatment of moderate to high myopia. SETTING: Department of Ophthalmology, Aarhus University Hospital, Aarhus, Denmark. DESIGN: Prospective clinical study. METHODS: For small‐incision lenticule extraction, an intrastromal lenticule was cut with a femtosecond laser and manually extracted without creation of a flap. Patients were treated and followed for 3 months. Only 1 randomly chosen eye of each patient was used in the statistical analyses. RESULTS: The study enrolled 144 patients. The mean preoperative spherical equivalent was −7.18 diopters (D) ± 1.57 (SD). Of eyes with emmetropia as target refraction, 40% had an uncorrected distance visual acuity of 0.1 logMAR or less 1 day after surgery; this increased to 73% at 3 months. The mean corrected distance visual acuity (CDVA) improved significantly from −0.01 (logMAR) preoperatively to −0.03 3 months postoperatively. None of the 127 eyes lost 2 lines or more of CDVA and 6 eyes lost 1 line of CDVA after 3 months. In contrast, 1 eye gained 2 lines and 24 eyes gained 1 line of CDVA. The achieved refraction was a mean of −0.09 ± 0.45 D from the attempted refraction. Of the eyes, 77% were within ±0.50 D and 95% were within ±1.00 D. Ninety‐five percent of the patients would recommend the procedure to others. CONCLUSIONS: The refractive predictability, safety, and patient satisfaction 3 months after small‐incision lenticule extraction were high and comparable to results in previous studies of femtosecond laser–assisted techniques. Financial Disclosure: Drs. Hjortdal and Asp received travel reimbursement from Carl Zeiss Meditec AG, Jena, Germany. No other author has a financial or proprietary interest in any material or method mentioned.

Predictors for the outcome of small-incision lenticule extraction for Myopia.

PURPOSE To study the influence of patient- and surgery-related parameters on the predictability, efficacy, and safety of small-incision lenticule extraction (SMILE) for treatment of myopia. METHODS This prospective, clinical quality, control study comprised 670 eyes from 335 patients with myopia up to -10.00 diopters (D) (spherical equivalent refraction) and astigmatism up to 2.00 D treated with SMILE in both eyes and followed for 3 months. RESULTS Preoperative mean spherical equivalent refraction was -7.19±1.30 D. In eyes with emmetropia as the target refraction, 84% obtained uncorrected distance visual acuity ≤ 0.10 logMAR (20/25 or better Snellen equivalent) at 3 months. Mean corrected distance visual acuity (CDVA) improved from -0.03 to -0.05 logMAR (P<.01). Two or more lines of CDVA were lost in 2.4% (16 eyes). The achieved refraction was 0.25±0.44 D less than attempted after 3 months, and 80% (537 eyes) and 94% (631 eyes) were within ±0.50 and ±1.00 D of attempted correction, respectively. Multiple linear regression analyses revealed that spherical equivalent refraction undercorrection was predicted by increasing patient age (0.10 D per decade; P<.01) and steeper corneal curvature (0.04 D per D; P<.01). Safety and efficacy of the procedure were minimally affected by age, gender, and simultaneous cylinder correction. CONCLUSIONS Undercorrection of 0.25 D and small effects of patient age and corneal curvature suggest that the standard nomogram for SMILE need only minor adjustments. This study suggests that safety and efficacy are not influenced to any clinically significant degree by easily discernible patient factors.

Femtosecond (FS) laser vision correction procedure for moderate to high myopia: a prospective study of ReLEx® flex and comparison with a retrospective study of FS-laser in situ keratomileusis

Purpose:  To present our initial clinical experience with ReLEx® flex (ReLEx) for moderate to high myopia. We compare efficacy, safety and corneal higher‐order aberrations after ReLEx with femtosecond laser in situ keratomileusis (FS‐LASIK).

Corneal biomechanical properties after LASIK, ReLEx flex, and ReLEx smile by Scheimpflug-based dynamic tonometry

PurposeTo evaluate corneal biomechanical properties after LASIK, ReLEx flex, and the flap-free procedure ReLEx smile by Scheimpflug-based dynamic tonometry (Corvis ST) and non-contact differential tonometry (Ocular Response Analyzer, ORA).MethodsPatients treated for high myopia (−10.5 to −5.5 diopters, spherical equivalent refraction) more than one year previously at Aarhus University Hospital were included. Treatments comprised LASIK (35 eyes), ReLEx flex (31 eyes), and ReLEx smile (29 eyes). A control group included 31 healthy eyes. Cornea-compensated IOP (IOPcc), corneal hysteresis (CH), and corneal resistance factor (CRF) were measured with ORA. Corneal applanation and deformation were registered with Corvis ST during an air-pulse.ResultsMultiple linear regression analysis showed that CH and CRF were significantly lower after all keratorefractive procedures compared to healthy controls (p < 0.05). No significant differences were observed in CH or CRF between the keratorefractive groups. Corvis ST showed no differences in radius at highest concavity (HC radius), time until first applanation (A1 Time), time until second applanation (A2 Time), and deflection length at highest concavity (HC deflection length) between groups. LASIK treated eyes had significantly shorter time until highest concavity than eyes treated with ReLEx smile (HC Time, p = 0.01). The A1 deflection length was significantly shorter in the keratorefractive groups compared to the healthy controls (p < 0.05).ConclusionsKeratorefrative procedures alter the corneal biomechanical properties with regard to corneal hysteresis and corneal resistant factor. The flap-based LASIK and ReLEx flex and the flap-free ReLEx smile result in similar reduction in corneal biomechanics when evaluated by Corvis ST and ORA.

Efficacy, safety, predictability, contrast sensitivity, and aberrations after femtosecond laser lenticule extraction.

Purpose To compare femtosecond lenticule extraction and small‐incision lenticule extraction to treat moderate to high myopia. Setting Department of Ophthalmology, Aarhus University Hospital, Aarhus, Denmark. Design Prospective clinical single‐masked paired‐eye study. Methods An intrastromal lenticule was cut by a femtosecond laser and manually extracted. In femtosecond lenticule extraction, a laser in situ keratomileusis–like flap allowed removal of the lenticule, whereas in small‐incision lenticule extraction, it was removed through a small incision. Follow‐up was 6 months. Results Thirty‐five patients were treated with femtosecond lenticule extraction in 1 eye and small‐incision lenticule extraction in the other. The mean preoperative spherical equivalent was −7.6 diopters (D) ± 1.0 (SD) (range −6.0 to −9.9 D). After both procedures, 90% of eyes had an uncorrected distance visual acuity of 20/40 or better 1 day postoperatively, increasing to 100% after 6 months. At 6 months, the mean corrected distance visual acuity (CDVA) improved significantly by approximately 1.5 letters on the logMAR chart. No eyes lost or gained 2 lines or more of CDVA after either procedure. The achieved refraction was a mean of −0.04 ± 0.38 D from the attempted refraction after femtosecond lenticule extraction and −0.09 ± 0.39 D after small‐incision lenticule extraction. After both procedures, 88% of eyes were within ±0.50 D. Contrast sensitivity was unchanged. The changes in higher‐order aberrations were similar. Conclusion The all‐femtosecond laser flap‐based and cap‐based techniques produced almost identical results up to 6 months postoperatively in eyes with moderate to high myopia. Financial Disclosure Dr. Hjortdal received travel reimbursement from Carl Zeiss Meditec AG. No other author has a financial or proprietary interest in any material or method mentioned.

Central Corneal Sublayer Pachymetry and Biomechanical Properties After Refractive Femtosecond Lenticule Extraction

PURPOSE To compare central corneal sublayer pachymetry and biomechanical properties after femtosecond lenticule extraction (FLEX) and small-incision lenticule extraction (SMILE). METHODS A prospective, randomized, single-masked clinical trial of 35 patients treated for moderate to high myopia with FLEX in one eye and SMILE in the other. Anterior segment optical coherence tomography imaging (Heidelberg Spectralis; Heidelberg Engineering GmbH, Heidelberg, Germany) was used to measure central corneal thickness (CCT) and epithelial, flap/cap, and residual stromal bed thickness centrally. The Ocular Response Analyzer (Reichert Ophthalmic Instruments, Buffalo, NY) was used to assess corneal hysteresis (CH) and corneal resistance factor (CRF). Patients were examined before and 6 months after surgery. RESULTS Mean decrease in CCT was 105 μm in FLEX-treated eyes and 106 μm in SMILE-treated eyes (P = .70), which is equivalent to approximately 14 μm/diopters corrected. Mean central epithelial thickness increased 7 ± 6 μm in FLEX-treated eyes and 6 ± 5 μm in SMILE-treated eyes (P = .64). Achieved mean flap/cap thickness was 4 ± 6 μm from the expected thickness in FLEX-treated eyes and 4 ± 9 μm in SMILE-treated eyes (P = .37). CH was reduced 2.7 ± 1.3 mm Hg in FLEX-treated eyes and 3.3 ± 1.2 mm Hg in SMILE-treated eyes (P = .08). CRF was reduced 4.5 ± 1.2 mm Hg in FLEX-treated eyes and 4.6 ± 1.2 mm Hg in SMILE-treated eyes (P = .71). CH and CRF were highly correlated with CCT, but not patient age. CONCLUSIONS In this paired-eye study, the flap-based FLEX and cap-based SMILE resulted in almost identical changes in central corneal sublayer pachymetry and biomechanical properties for moderate to high myopia 6 months after treatment.

Past and present of corneal refractive surgery: A retrospective study of long- term results after photorefractive keratectomy and a prospective study of refractive lenticule extraction

Surgical correction of refractive errors is becoming increasingly popular. In the 1990s, the excimer laser revolutionized the field of corneal refractive surgery with PRK and LASIK, and lately refractive lenticule extraction (ReLEx) of intracorneal tissue, using only a femtosecond laser, has become possible. Two new procedures were developed, ReLEx flex (FLEX) and ReLEx smile (SMILE).

Long-term Outcomes of Photorefractive Keratectomy for Low to High Myopia: 13 to 19 Years of Follow-Up

PURPOSE To evaluate long-term outcomes after photorefractive keratectomy (PRK). METHODS A retrospective follow-up study of patients who received PRK at 5.0- to 6.5-mm optical zones, using the Summit broad beam excimer laser (Summit Technology, Inc., Waltham, MA) at Odense University Hospital, Odense, Denmark, between 1992 and 1998. One randomly selected eye of each patient was used in the statistical analyses. Re-treated eyes were excluded. RESULTS One hundred sixty eyes were included. Mean follow-up time was 16 years (range: 13 to 19 years). Mean preoperative spherical equivalent was -4.84 ± 2.95 diopters (D) (range: -20.25 to -1.25 D). At last follow-up examination, achieved refraction was -1.00 ± 1.56 D (range: -10.75 to +1.00 D) from attempted refraction, and the change in mean refractive error from 6 months postoperatively was less than 1.00 D. Results from a subgroup of unilateral treated patients indicated that myopic progression was the main reason for the residual refractive error. For eyes with low myopia (n = 124), the proportion of eyes within ± 1.0 D of attempted refraction was 72%, and for eyes with high myopia (-6.00 D or more, n = 36) it was 47%. Forty-five percent had uncorrected distance visual acuity of 20/20 or better at last follow-up examination. Three eyes (2%) lost two or more lines and 13 eyes (8%) gained two or more lines of corrected distance visual acuity. Fourteen percent had haze (grade 0.5 to 2). Eighty-one percent were satisfied with the surgery. CONCLUSION PRK for low degrees of myopia seemed safe and effective up to 19 years after surgery with conventional broad beam laser ablation. Refractive predictability was significantly lower and the occurrence of haze was higher in eyes with high myopia.

Inverse cutting of posterior lamellar corneal grafts by a femtosecond laser.

Purpose Posterior lamellar grafting of the cornea has become the preferred technique for treatment of corneal endothelial dysfunction. Posterior lamellar grafts are usually cut by a micro-keratome or a femto-second laser after the epithelial side of the donor cornea has been applanated. This approach often results in variable central graft thickness in different grafts and an increase in graft thickness towards the periphery in every graft. The purpose of this study was to evaluate if posterior lamellar grafts can be prepared from the endothelial side by a femto-second laser, resulting in reproducible, thin grafts of even thickness. Methods A CZM 500 kHz Visumax femto-second laser was used. Organ cultured donor grafts were mounted in an artifical anterior chamber with the endothelial side up and out. Posterior grafts of 7.8 mm diameter and 130 micron thickness were prepared by femto-second laser cutting. A standard DSAEK procedure was performed in 10 patients with Fuchs endothelial dystrophy. Patients were followed-up regularly and evaluated by measurement of complications, visual acuity, corneal thickness (Pentacam HR), and endothelial cell density. Results Femto-laser cutting of grafts and surgery was uncomplicated. Rebubbling was necessary in 5 of 10 cases (normally only in 1 of 20 cases). All grafts were attached and cleared up during the first few weeks. After six months, the average visual acuity was 0.30 (range: 0.16 to 0.50), corneal thickness was 0.58 mm (range 0.51 to 0.63), and endothelial cell density was 1.570 per sq. mm (range: 1.400 to 2.000 cells per sq. mm). The grafts were of uniform thickness, but substantial interface haze was present in most grafts. Conclusions Posterior lamellar corneal grafts can be prepared from the endothelial side using a femto-second laser. All grafts were clear after 6 months with satisfying endothelial cell counts. Poor visual acuity caused by interface scatter was observed in most patients. Femto-second laser cutting parameters needs to be optimised to enable smooth cutting in the posterior stroma.

Establishment of a validated training programme on the Eyesi cataract simulator. A prospective randomized study

To establish and evaluate a systematic training programme to be included into the ophthalmologic resident curriculum.