Maria I. Kalyvianaki

Epi-LASIK: Comparative histological evaluation of mechanical and alcohol-assisted epithelial separation

Purpose: To compare the effect of mechanical and alcohol‐assisted excision on the histological ultrastructure of epithelial disks from human corneas. Setting: Vardinoyiannion Eye Institute of Crete, University of Crete, Medical School, Crete, Greece. Methods: Ten eyes of 10 patients were deepithelialized by 1 of 2 two techniques. In 6 eyes, a customized instrument was used to mechanically separate the epithelial layer. In 4 eyes, the epithelial disks were obtained using the conventional laser‐assisted subepithelial keratectomy (LASEK) technique; that is, with alcohol concentrations of 15% and 20%. All specimens were assessed by light and electron microscopy, and the histological findings of the 2 methods were compared. Results: Transmission electron microscopy showed that when the epithelial disks were excised by mechanical separation, the lamina densa and lamina lucida were preserved and the hemidesmosomes had normal morphology along almost the entire length of the basement membrane. The basal epithelial cells of the separated epithelial disks showed minimal trauma and edema. Specimens obtained using 15% and 20% alcohol concentrations showed formation of cytoplasmic fragments of the basal epithelial cells, enlargement of the intercellular spaces, and extensive discontinuities in the basement membrane, which was excised at the level of the lamina lucida. Conclusions: Mechanical separation did not affect the normal cell morphology of the excised epithelial disks. Transmission electron microscopy of the specimens proved the manual technique is less invasive to epithelial integrity than LASEK using either alcohol concentration.

Advances in subepithelial excimer refractive surgery techniques: Epi-LASIK.

The reports of an increasing incidence of iatrogenic ectasia, the evolution of wavefront aberrometry, and the suggestion that the laser in situ keratomileusis flap could lead to unpredictable biomechanical corneal changes have renewed interest in surface ablation and have set the stage for the introduction of alternative photorefractive treatment modalities. The theoretical advantage of surface procedures, such as laser epithelial keratomileusis that preserve the epithelial button, stems from the repositioning of the epithelial flap over the laser-ablated corneal surface. This epithelial sheet is thought to act as a natural contact lens that decreases postoperative pain and haze formation. Epipolis laser in situ keratomileusis is an alternative modality of epithelial separation with the use of a device that features a blunt oscillating blade. This surgical approach does not require the use of alcohol for epithelial loosening.

One-Year Follow-up of Corneal Confocal Microscopy After Corneal Cross-Linking in Patients With Post Laser In Situ Keratosmileusis Ectasia and Keratoconus

PURPOSE To investigate corneal tissue alterations after corneal collagen cross-linking in patients with post laser in situ keratosmileusis (LASIK) keratectasia and keratoconus. DESIGN Prospective comparative case series. METHODS Five patients (5 eyes) with iatrogenic keratectasia after LASIK and 5 patients (5 eyes) with progressive keratoconus were included. All eyes underwent corneal cross-linking and were assessed by corneal in vivo confocal microscopy. Three normal/healthy and 3 post-LASIK without ectasia corneas were also examined as controls. RESULTS All corneas revealed normal epithelial thickness before and after surgery. Images of both keratoconic and post-LASIK corneal ectasia eyes revealed similar morphologic alterations. The subepithelial nerve plexus was absent immediately after treatment; regeneration of nerves was evident after the third postoperative month. Keratocytes were absent from the anterior 300 mum of the stroma in the first 3 months while the posterior stromal density of keratocytes was increased. Corneal collagen fibers in the anterior stroma were distributed unevenly in a net-like formation. Full-thickness keratocyte repopulation in the anterior and mid-corneal stroma was detected 6 months after treatment. The corneal endothelium did not undergo any significant changes, since the cell density and hexagonality was not found altered during the follow-up period. CONCLUSIONS Keratocyte nuclei apoptosis in the anterior and intermediate corneal stroma along with collagen alterations were observed during the first 3 postcorneal cross-linking months. Gradual keratocyte repopulation was demonstrated over the following months. Corneal alterations after corneal cross-linking were similar in both keratoconic and post-LASIK corneal ectasia eyes.

Epi-LASIK: Preliminary clinical results of an alternative surface ablation procedure

Purpose: To evaluate the clinical results of epi‐LASIK, a new surface ablation surgical technique for the treatment of low myopia. Setting: Vardinoyannion Eye Institute of Crete, University of Crete, Greece. Methods: Forty‐four eyes of 31 patients had epi‐LASIK for the correction of low myopia. Mean preoperative spherical equivalent was 3.71 diopters (D) ± 1.2 (SD) (range −1.75 to −7.00 D) and the mean baseline logMAR best spectacle‐corrected visual acuity was −0.01 ± 0.06 (range 0.10 to −0.10). All the epithelial separations were performed with the Centurion epikeratome (CIBA Surgical). The enrolled patients were followed daily until the epithelial healing was complete as well as at 1‐ and 3‐month intervals. On the operative day, patients filled out a questionnaire grading visual performance and pain score of treated eyes every 2 hours for a total of 5 records. Results: The mean epithelial healing time was 4.86 ± 0.56 days (range 3 to 5 days). The mean logMAR uncorrected visual acuity on the day of reepithelization was 0.19 ± 0.09 (range 0.40 to 0.10). At 1 month, the mean was spherical equivalent of the treated eyes (N = 44), −0.3 ± 0.6 D (range −1.0 to 0.87 D), and at 3 months it was (N = 37), −0.10 ± 0.4 D (range −0.75 to 0.75 D); 97% of eyes had clear corneas or trace haze 3 months after treatment. Conclusions: Preliminary clinical results suggest that epi‐LASIK is a safe and efficient method for the correction of low myopia. Further studies will establish this method as an alternative surface ablation procedure.

Phakic refractive lens implantation in high myopic patients ☆: One-year results

Purpose: To evaluate the efficacy and safety of implantation of a new posterior chamber phakic refractive lens (PRL, Ciba Vision Surgical) in highly myopic eyes. Setting: Department of Ophthalmology, Medical School, University of Crete, Vardinoyannion Eye Institute of Crete, Crete, Greece. Methods: Thirty‐four myopic eyes of 19 patients were treated for high myopia with implantation of a silicone PRL in the posterior chamber. Mean patient age was 29.0 years ± 7.9 (SD) (range 18 to 44 years). Manifest refraction in spherical equivalent (MR), uncorrected (UCVA) and best corrected (BCVA) visual acuity (decimal scale), intraocular pressure, higher‐order aberrations (root‐mean‐square [RMS] wavefront error measured with a Shack‐Hartmann wavefront sensor WASCA analyzer [Carl Zeiss, Meditec]), possible complications, and subjective symptoms were evaluated. Results: Phakic refractive lenses were successfully implanted in all eyes. Mean follow‐up was 17.17 ± 3.76 months (range 12 to 24 months). There was a statistically significant reduction in the MR (from −14.70 D ± 2.65 D [range −20.75 D to −10.50 D] to −0.61 D ± 0.89 D [range −2.25 D to 1.00 D]) (P<.001). Twenty‐seven (79%) and 15 eyes (44%) were within ±1.00 D and ±0.50 D of target refraction, respectively. Mean UCVA significantly improved (from counting fingers to 0.62 ± 0.28 (range 0.08 to 1.20) (P<.001). Mean BCVA also improved from 0.70 ± 0.24 (range 0.10 to 1.00) to 0.85 ± 0.24 (range 0.10 to 1.20) (P<0.001). Overall, there was a mean increase in BCVA of 1.5 ± 1.5 lines (range loss of 2 lines to gain of 5 lines). There was no statistically significant difference in higher‐order aberrations after PRL implantation (pre‐PRL RMS: 0.18 &mgr;m ± 0.08 &mgr;m [range 0.09 &mgr;m to 0.38 &mgr;m]; post‐PRL RMS: 0.21 &mgr;m ± 0.08 &mgr;m; [range 0.05 &mgr;m to 0.38 &mgr;m]) (P = .12). Conclusion: The PRL showed encouraging results in treating high myopia. Additional patients and longer follow‐up period are needed to detect the long‐term efficacy and safety of this refractive lens.

Comparison of Epi-LASIK and Off-Flap Epi-LASIK for the Treatment of Low and Moderate Myopia

PURPOSE To compare the early postoperative course and the 1-year clinical results of off-flap Epi-LASIK and Epi-LASIK for the treatment of low and moderate myopia. DESIGN Pilot double-masked, randomized, comparative study. PARTICIPANTS Fifty-six patients (112 myopic eyes). METHODS Epithelium was separated in all eyes with the use of Centurion SES epikeratome (Norwood Abbey EyeCare, Vic, Australia). The first eye treated and surgical method in the first eye were randomized. One eye of each patient underwent standard Epi-LASIK, whereas in the contralateral eye, the epithelial sheet was not retained on the photoablated stroma (off-flap Epi-LASIK eyes). Mean preoperative spherical equivalent was -3.50+/-1.22 diopters (D; range, -1.75 to -6.37 D) in Epi-LASIK eyes and -3.61+/-1.22 D (range, -1.50 to -6.50 D) in off-flap Epi-LASIK eyes (P>0.05, paired Student t test). Excimer laser corneal ablation was performed using the Allegretto 200Hz (Wavelight Laser Technologie AG, Erlangen, Germany). Patients were followed up daily until the epithelial healing was complete and at 1, 3, 6, and 12 months. MAIN OUTCOME MEASURES Epithelial healing time, subjective pain score, and uncorrected visual acuity (UCVA) were evaluated during the first postoperative days. Uncorrected visual acuity, spherical equivalent refraction, best spectacle-corrected visual acuity, haze scores, and wavefront aberrations were recorded at all subsequent intervals. RESULTS Time of epithelial healing did not differ significantly in Epi-LASIK and off-flap Epi-LASIK eyes (4.76+/-0.84 days in Epi-LASIK eyes vs. 4.54+/-0.93 days in off-flap Epi-LASIK eyes). No significant difference in UCVA was found after the 2 techniques during the first postoperative days. Subjective pain score was lower in off-flap Epi-LASIK eyes at 2 postoperative hours, whereas no significant difference in pain scores was noted between the 2 techniques at the other intervals. There was no significant difference in spherical equivalent, line gain or loss, haze scores, and higher-order aberrations between Epi-LASIK and off-flap Epi-LASIK eyes at any interval. Uncorrected visual acuity was significantly better in Epi-LASIK eyes only at 6 months (-0.05+/-0.08 in Epi-LASIK eyes vs. 0.00+/-0.07 in off-flap Epi-LASIK eyes). Preoperative wavefront aberrations did not change significantly 1 year after either procedure. CONCLUSIONS Epi-LASIK and off-flap Epi-LASIK had equal visual and refractive results for the treatment of low and moderate myopia in this study. FINANCIAL DISCLOSURE(S) Proprietary or commercial disclosure may be found after the references.

Epipolis laser in-situ keratomileusis: an evolving surface ablation procedure for refractive corrections.

Purpose of review The aim of this article is to provide an update on epipolis laser in-situ keratomileusis – an alternative surface photorefractive surgical technique for the correction of myopia. Recent findings In-vivo studies on animal models provide evidence that the replacement of the epithelial sheet on an ablated cornea can control corneal wound healing. Preliminary clinical data confirm that epipolis laser in-situ keratomileusis can provide excellent long-term visual and refractive results. The problems of late visual rehabilitation and postoperative pain, however, have not yet been fully addressed. Summary Being a recently introduced surgical photorefractive technique for ametropias correction, epipolis laser in-situ keratomileusis is a fast evolving area of interest for refractive surgeons.

Long-term results of phakic refractive lens implantation in eyes with high myopia.

PURPOSE To evaluate the long-term results of phakic refractive lens (PRL; Carl Zeiss Meditec) implantation in eyes with high myopia. METHODS In this retrospective, noncomparative, interventional case series, 143 myopic eyes of 82 patients were treated for high myopia with the implantation of the silicone PRL in the posterior chamber. RESULTS Mean follow-up was 3.8±1.7 years (range: 1 to 6 years). Six years postoperatively (n=34), a statistically significant reduction was noted in the cycloplegic spherical equivalent from -14.08±4.00 diopters (D) (range: -24.88 to -4.75 D) before PRL implantation to -0.45±0.62 D (range: -1.00 to 1.00 D) (P<.001). At 6 years, 67.6% (23 eyes) and 91.2% (31 eyes) were within ±0.50 and ±1.00 D of target refraction, respectively. Mean logMAR uncorrected and corrected distance visual acuity improved significantly (P<.001) (counting fingers preoperatively in all eyes to 0.17±0.15 [range: 0.54 to -0.06] and 0.19±0.19 [1.00 to -0.08] to 0.07±0.10 [range: 0.30 to -0.10], respectively). Complications included anterior capsule damage (3 eyes), temporary intraocular pressure increase (14 eyes), pigment dispersion (1 eye), and PRL decentration (1 eye). No eyes presented any signs of cataract up to 6 years postoperatively. CONCLUSIONS Long-term results show that PRL implantation is an effective and safe method for treating high myopia.

Occlusion Therapy of Unilateral Amblyopia with Botulinum Toxin Induced Ptosis

In order to evaluate the role of botulinum toxin induced ptosis as an occlusion method to treat unilateral deep strabismic amblyopia in two uncooperative children, we injected 0.2 ml of diluted botulinum toxin in the levator palpaebrae; low sedation was necessary in one of the two children. In both cases a marked ptosis was achieved, which lasted about four weeks and then gradually resolved completely. The visual acuity of the ablyopic eye increased in both children, making patching easy thereafter. One child developed amblyopia in the injected eye, which was handled successfully using part-time occlusion. No other side effects were noted. Whether this new method could be a simple, safe and effective alternative method of occlusion for the treatment of deep amblyopia in uncooperative children needs to be proven with a larger series of children.

Fifteen-Year Follow-up After Anterior Chamber Phakic Intraocular Lens Implantation in One and LASIK in the Fellow Eye

Purpose: To report a patient fifteen years after anterior chamber phakic intraocular lens (AC-PIOL) implantation in one and laser in situ keratomileusis (LASIK) in the fellow eye. Methods: Case report. Results: A 56-year-old male underwent AC-PIOL implantation in one eye and LASIK in the fellow eye fifteen years ago. Preoperative uncorrected visual acuity (UCVA) was finger count in both eyes. Preoperative best spectacle-corrected visual acuity (BSCVA) was 20/25 (−16.75 −0.50 × 40) in the LASIK eye and 20/32 (−24.50 −0.50 × 90) in the AC-PIOL eye. Fifteen years postoperatively, UCVA was finger count in the LASIK eye and 20/200 in the AC-PIOL eye, while BSCVA was 20/32 and 20/25, respectively. Endothelial cell density (ECD) was 2020±47 in the LASIK eye and 945±22 in the AC-PIOL eye. Conclusion: Both procedures had similar visual outcomes. Furthermore, lower ECD was found in the AC-PIOL eye in comparison to the LASIK eye.