George A. Kounis

Simultaneous topography-guided PRK followed by corneal collagen cross-linking for keratoconus.

PURPOSE To present the results after simultaneous photorefractive keratectomy (PRK) followed by corneal collagen cross-linking (CXL) for progressive keratoconus. METHODS Twelve patients (14 eyes) with progressive keratoconus were prospectively treated with customized topography-guided PRK with the Pulzar Z1 (wavelength 213 nm, CustomVis) immediately followed by corneal collagen CXL with the use of riboflavin and ultraviolet A irradiation. RESULTS Mean follow-up was 10.69+/-5.95 months (range: 3 to 16 months). Mean preoperative spherical equivalent refraction (SE) was -3.03+/-3.23 diopters (D) and defocus was 4.67+/-3.29 D; at last follow-up SE and defocus were statistically significantly reduced to -1.29+/-2.05 D and 3.04+/-2.53 D, respectively (P<.01). Preoperative mean (logMAR) uncorrected visual acuity was 0.99+/-0.81 and best spectacle-corrected visual acuity was 0.21+/-0.19, which improved postoperatively to 0.16+/-0.15 and 0.11+/-0.15, respectively. The mean steepest keratometry was reduced from 48.20+/-3.40 D preoperatively to 45.13+/-1.80 D at last follow-up. CONCLUSIONS Simultaneous PRK followed by CXL seems to be a promising treatment capable of offering functional vision in patients with keratoconus.

Corneal Collagen Cross-linking With Riboflavin and Ultraviolet-A Irradiation in Patients With Thin Corneas

PURPOSE To report the outcomes after corneal collagen cross-linking (CXL) treatment with riboflavin and ultraviolet-A (UVA) irradiation in patients with thin corneas (minimum corneal thickness less than 400 μm after epithelial removal and before riboflavin instillation). DESIGN Prospective case series. METHODS Twelve patients (14 eyes, with minimum corneal thickness less than 400 μm after epithelial removal) were included in the study. All patients underwent riboflavin-UVA-induced CXL using the standard CXL (Dresden) protocol. Uncorrected distance visual acuity (UDVA) and corrected distance visual acuity (CDVA) (decimal scale), manifest refraction (diopters, D), and topography were evaluated at baseline and at 1, 3, 6, and 12 months follow-up. Images of the endothelium were acquired with a modified confocal scanning laser ophthalmoscope. RESULTS No intraoperative or postoperative complications were observed in this patient series. Mean minimum preoperative corneal thickness at the apex of the cone after epithelial removal and before riboflavin instillation was 373.92 ± 22.92 μm (range 340-399 μm). UDVA and CDVA improved from 0.25 ± 0.15 and 0.40 ± 0.20 to 0.27 ± 0.17 and 0.49 ± 0.20 respectively at the last follow-up examination. There was a reduction of the mean keratometry readings from 51.99 ± 5.57 D to 49.33 ± 4.82 D at the last follow-up. A significant decrease of endothelial cell density was observed (preoperative: 2733 ± 180 cells/mm(2) [range 2467-3016], last follow-up visit: 2441 ± 400 cells/mm(2) [range 1448-2920], P < .01). CONCLUSIONS CXL in thin corneas with minimum corneal thickness less than 400 μm after epithelial removal seems to result in a significant endothelial cell density decrease postoperatively. This finding was not related to other intraoperative or postoperative complications.

Intraoperative Pachymetric Measurements during Corneal Collagen Cross-Linking with Riboflavin and Ultraviolet A Irradiation

OBJECTIVE To study central corneal pachymetric variations during corneal collagen cross-linking (CXL) treatment with the use of riboflavin and ultraviolet A irradiation (UVA). DESIGN Prospective, noncomparative, interventional clinical study. PARTICIPANTS Fifteen keratoconic patients (19 eyes) were enrolled. METHODS All patients underwent riboflavin-UVA-induced corneal CXL. Intraoperative central corneal thickness (CCT) measurements using ultrasound pachymetry were performed during the procedure. Measurements were obtained after epithelial removal, after riboflavin drop instillation, and every 5 minutes (6 interval times) during UVA irradiation (30 minutes). MAIN OUTCOME MEASURES Central corneal thickness measurements. RESULTS Mean patient age was 26.9+/-6.5 years (range, 17-40 years). Ten were male and 5 were female. Mean preoperative CCT was 458.5+/-21.5 microm (range, 427-494 microm; 95% confidence interval [CI], 448-467 microm) and 415.7+/-20.6 microm (range, 400-468 microm; 95% CI, 406-426 microm) before and after epithelial removal, respectively. There was a statistically significant decrease (mean, 75 microm) of CCT between the epithelial removal interval (415.7+/-20.6 microm; range, 400-468 microm) and at the end of riboflavin solution instillation (340.7+/-22.9 microm; range, 292-386 microm; P<0.001). There was no statistically significant change in CCT during irradiation (P>0.05). There was no statistically significant difference between preoperative and 1-month postoperative endothelial cell count (preoperative, 2780+/-197 to 1-month postoperative, 2713+/-116; P = 0.14). No intraoperative, early postoperative, or late postoperative complications were observed in this patient series. CONCLUSIONS During corneal CXL with the use of riboflavin and UVA irradiation, a statistically significant decrease of CCT was demonstrated.

Simultaneous Topography-Guided Photorefractive Keratectomy Followed by Corneal Collagen Cross-linking for Keratoconus

PURPOSE To present the long-term results after simultaneous photorefractive keratectomy followed by corneal collagen cross-linking for keratoconus. DESIGN Prospective, interventional, consecutive case series. METHODS In this study, 26 patients (31 eyes) with progressive keratoconus were included. All patients underwent customized topography-guided photorefractive keratectomy immediately followed by corneal collagen cross-linking with the use of riboflavin and ultraviolet A irradiation. Epithelium was removed by transepithelial phototherapeutic keratectomy in all cases. RESULTS Mean follow-up was 19.53 ± 3.97 months (range, 12 to 25 months). Mean preoperative spherical equivalent was -2.3 ± 2.8 diopters (D), whereas at the last follow-up examination, it was significantly (P < .001) reduced to -1.08 ± 2.41 D. Logarithm of the minimal angle of resolution uncorrected and best-corrected visual acuity were reduced significantly by 0.46 and 0.084 (P < .001), respectively, at the last follow-up examination. Finally, mean steep and flat keratometry readings were reduced by 2.35 (P < .001) and 1.18 (P = .013) at the last follow-up examination. CONCLUSIONS Simultaneous photorefractive keratectomy followed by corneal collagen cross-linking seems to be a promising treatment alternative in our series of keratoconic patients.

Combined transepithelial phototherapeutic keratectomy and corneal collagen cross-linking for progressive keratoconus.

PURPOSE To compare the outcomes of corneal collagen cross-linking (CXL) for the treatment of progressive keratoconus using 2 different techniques for epithelial removal: transepithelial phototherapeutic keratectomy (t-PTK) versus mechanical epithelial debridement. DESIGN Prospective, comparative, interventional case series. PARTICIPANTS Thirty-four patients (38 eyes) with progressive keratoconus were enrolled. METHODS All patients underwent uneventful CXL treatment. Sixteen patients (19 eyes) underwent epithelial removal using t-PTK (group 1) and 18 patients (19 eyes) underwent mechanical epithelial debridement using a rotating brush (group 2) during CXL treatment. Visual and refractive outcomes were evaluated along with corneal confocal microscopy findings preoperatively and at 1, 3, 6, and 12 months postoperatively. MAIN OUTCOME MEASURES Uncorrected distance visual acuity (UDVA), corrected distance visual acuity (CDVA), manifest refraction, and keratometry readings. RESULTS No intraoperative or postoperative complications were observed in any of the patients. In group 1, logarithm of the minimum angle of resolution mean UDVA and mean CDVA improved from 0.99 ± 0.71 and 0.30 ± 0.26 preoperatively to 0.63 ± 0.42 (P = 0.02) and 0.19 ± 0.18 (P = 0.008) at 12 months postoperatively, respectively. In group 2, neither mean UDVA nor mean CDVA demonstrated a significant improvement at 12 months postoperatively (P>0.05). In group 1, mean corneal astigmatism improved from -5.84 ± 3.80 diopters (D) preoperatively to -4.31 ± 2.90 D (P = 0.015) at the last follow-up, whereas in group 2 there was no significant difference at the same postoperative interval (P>0.05). No endothelial cell density alterations were observed throughout the follow-up period for both groups (P>0.05). CONCLUSIONS Epithelial removal using t-PTK during CXL results in better visual and refractive outcomes in comparison with mechanical epithelial debridement.

Management of pellucid marginal corneal degeneration with simultaneous customized photorefractive keratectomy and collagen crosslinking

A 34-year-old woman had simultaneous photorefractive keratectomy and corneal collagen crosslinking with riboflavin-ultraviolet-A irradiation for the treatment of progressive pellucid marginal corneal degeneration in both eyes. No intraoperative or early postoperative complications occurred. Twelve months postoperatively, the uncorrected visual acuity was assessed at 20/40 in both eyes compared with counting fingers preoperatively. The corrected visual acuity also improved from 20/50 and 20/63 to 20/25 and 20/32 in the right eye and left eye, respectively. Corneal topography revealed a significant improvement in both eyes. Despite the encouraging results, longer follow-up is necessary to confirm the stability of the results.

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.

Two-year follow-up of conductive keratoplasty for the treatment of hyperopic astigmatism.

PURPOSE: To evaluate the safety, efficacy, predictability, and stability of conductive keratoplasty (CK) for the treatment of hyperopic astigmatism. SETTING: University of Crete Medical School, Vardinoyannion Eye Institute of Crete, Heraklion, Greece. METHODS: In this prospective nonrandomized noncontrolled single‐center study, 47 eyes of 34 patients (15 women and 19 men) were treated for hyperopic astigmatism (up to + 3.50 diopters [D]) with a Refractec ViewPoint CK system and followed for 24 months ± 0.6 (SD). The treatment consisted of 4 to 36 spots applied to the periphery of the cornea. Mean age was 48.5 years ± 9.7 years, range 25 to 68 years. All the treated eyes were analyzed for safety, efficacy, predictability, and stability. RESULTS: The mean patient age was 48.5 ± 9.7 years (range 25 to 68 years). Preoperatively, the mean manifest refraction spherical equivalent (MRSE) was +2.11 ± 0.88 D (range −0.50 to + 4.13 D); at 12 months, it was −0.52 ± 0.73 D and at 24 months, −0.50 ± 0.77 D. At 24 months, the mean MRSE was within ±0.50 D in 61% of eyes, within ±1.00 D in 83%, and within ±2.00 D in all eyes. At 24 months, the uncorrected visual acuity was 20/20 or better in 37% of eyes and 20/40 or better in 97%. By the end of the follow‐up period, no eye had lost ≥2 Snellen lines or had an induced cylinder ≥1.50 D. CONCLUSIONS: Conductive keratoplasty for low hyperopic astigmatism was a safe, effective, and stable procedure. Nomogram adjustments and careful patient selection should contribute to higher levels of predictability when treating hyperopic astigmatism.

Femtosecond laser-assisted corneal pocket creation using a mask for inlay implantation.

PURPOSE To describe the technique of femtosecond laser-assisted intracorneal pocket creation, using a mask for the implantation of a corneal inlay in the non-dominant eye of a 56-year-old, emmetropic, presbyopic woman for the correction of presbyopia. METHODS Using the iFlap treatment-type software of the femtosecond laser (IntraLase 150, Abbott Medical Optics), a full lamellar cut was created at 280-μm depth. A keyhole-shaped mask was placed at the internal part of the glass of the applanation cone. A separator was used to separate the stroma, and an inserter was used to implant the inlay at the center of the line of sight. To determine the line of sight, the microscope and centration system of the excimer laser (Allegretto Wave 400 Hz, WaveLight Laser Technologie AG) were used. The Flexivue Microlens inlay (Presbia) was implanted. RESULTS No intra- or postoperative complications occurred during follow-up. Uncorrected near visual acuity improved from 20/50 to 20/20 at the first postoperative week. CONCLUSIONS Femtosecond-assisted intracorneal pocket creation using a mask is a simple, safe, and efficient approach for the implantation of corneal inlays.

Intraocular pressure measurements after corneal collagen crosslinking with riboflavin and ultraviolet A in eyes with keratoconus.

PURPOSE: To determine the possible effect of corneal collagen crosslinking (CXL) with riboflavin and ultraviolet A (UVA) on intraocular pressure (IOP) measurements by Goldmann applanation tonometry (GAT). SETTING: Institute of Vision and Optics, Faculty of Medicine, University of Crete, Heraklion, Crete, Greece. DESIGN: Prospective case series. METHODS: This noncomparative study measured IOP by GAT before CXL and 6 months and 12 months after CXL. RESULTS: The study evaluated 55 eyes (55 patients). There was a statistically significant increase in the measured IOP 6 months and 12 months after CXL (both P<.001). The mean measured IOP was 9.95 mm Hg ± 3.01 (SD) before CXL, 11.40 ± 2.89 mm Hg at 6 months, and 11.35 ± 3.38 mm Hg at 12 months. The change in IOP measurements at both postoperative examinations was not correlated with patient age, preoperative pachymetry, or preoperative keratometry readings. CONCLUSION: After riboflavin–UVA CXL in eyes with keratoconus, there was a significant increase in IOP measured by GAT that was probably caused by an increase in corneal rigidity. Financial Disclosure: No author has a financial or proprietary interest in any material or method mentioned.