Nikolaos Astyrakakis

Corneal ectasia induced by laser in situ keratomileusis

Purpose: To identify factors that can lead to corneal ectasia after laser in situ keratomileusis (LASIK). Setting: University refractive surgery center. Methods: In this retrospective study, the charts of all patients (2873 eyes) who had LASIK between May 1995 and November 1999 were reviewed. Fourteen patients (19 eyes, 0.66%) developed post‐LASIK ectasia. The mean follow‐up was 16.32 months (range 6 to 42 months). Results: No patient with an attempted correction less than 8.00 diopters or a residual corneal bed thickness greater than 325 &mgr;m experienced post‐LASIK ectasia. There was a statistically significant positive correlation between corneal residual bed thickness and increasing patient age. Conclusion: Despite the limitations of the small sample size, the studys results suggest that parameters besides residual corneal bed thickness (eg, age, attempted correction) may have to be considered to avoid post‐LASIK ectasia.

Eleven-year follow-up of laser in situ keratomileusis.

PURPOSE: To report the long‐term (11‐year) outcomes (stability and complications) of laser in situ keratomileusis (LASIK) in patients with high myopia. SETTING: University refractive surgery center. METHODS: Seven patients (4 with bilateral treatment and 3 with unilateral treatment) who had myopic LASIK and completed 11 years of follow‐up were included in the study. RESULTS: The mean age of the 2 men and 5 women was 41.7 years ± 6.5 (SD) (range 34 to 50 years). The mean follow‐up was 140.18 ± 6.70 months (range 132 to 150 months). At 11 years, the spherical equivalent error was statistically significantly reduced, from a mean of −12.96 ± 3.17 diopters (D) (range −19.00 to −10.00 D) before LASIK to a mean of −1.14 ± 1.67 D (range −4.25 to 1.00 D) after (P<.001). Predictability of postoperative refraction 6 months and 11 years after LASIK showed that 6 eyes (55%) were within ±1.00 D of intended correction. No late postoperative complications occurred. Five patients (8 eyes, 73%) were satisfied with the final outcome. CONCLUSIONS: Laser in situ keratomileusis was moderately predictable in the correction of high degrees of myopia. After the sixth postoperative month, refractive and topographic stability were obtained. No long‐term sight‐threatening complications occurred during the follow‐up period.

Long-term results of conductive keratoplasty for low to moderate hyperopia.

PURPOSE: To assess the long‐term safety, efficacy, predictability, and stability of conductive keratoplasty (CK) for the treatment of low to moderate hyperopia and to evaluate the impact of the procedure on the quality of vision. SETTING: University of Crete, Medical School, Vardinoyannion Eye Institute of Crete, Crete, Greece. METHODS: In this prospective nonrandomized noncontrolled single‐center study, 38 eyes of 26 patients (13 women and 13 men) were treated for hyperopia with a Refractec ViewPoint CK system and followed for 30 months. Preoperatively, the mean manifest refraction spherical equivalent (MRSE) was +1.89 diopters (D) ± 0.6 (SD) (range +1.00 to +3.25 D), and the mean follow‐up was 30.9 ± 1.1 months. All eyes were treated with the regular CK nomogram for the treatment of spherical hyperopia. The treatment consisted of 8 to 32 spots applied to the periphery of the cornea. Mean age was 50.3 ± 8.8 years (range 31 to 71 years). All treated eyes were analyzed for safety, efficacy, predictability, and stability. RESULTS: At 12 months, the MRSE was −0.06 ± 0.8 D and at 30 months was −0.02 ± 0.7 D. At 30 months, the mean MRSE was within ±0.50 D in 68%, within ±1.00 D in 92%, and within ±2.00 D in all eyes. At 30 months, uncorrected visual acuity was 20/20 or better in 52.5% and 20/40 or better in 89% of eyes. No eye lost 2 or more Snellen lines or had an induced cylinder of 2.00 D or greater. The procedure did not cause statistically significant changes in contrast sensitivity. CONCLUSION: Results show that CK for low to moderate hyperopia is a safe, effective, predictable, and stable procedure.

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.

Efficacy of 2 types of silicone hydrogel bandage contact lenses after photorefractive keratectomy

PURPOSE: To compare the efficacy of 2 types of silicone hydrogel bandage contact lenses with high oxygen transmissibility after photorefractive keratectomy (PRK). SETTING: Institute of Vision and Optics, Faculty of Medicine, University of Crete, Heraklion, Crete, Greece. METHODS: In this prospective study, 1 eye of patients having bilateral PRK was randomly fitted with a bandage contact lens of lotrafilcon A (Night & Day) and the fellow eye, with a bandage contact lens of lotrafilcon B (O2Optix). The patients and the examiner were masked to which bandage contact lens type was in which eye. Patients were examined on the day of surgery and 1, 3, and 5 days postoperatively. Postoperative examinations included uncorrected distance visual acuity and slitlamp biomicroscopy to assess epithelial defect size. Subjective evaluation of pain and vision was recorded 1, 2, 3, and 4 days postoperatively. RESULTS: The study enrolled 44 patients (88 eyes). The mean epithelial defect size immediately after surgery was 47.0 mm2 with both types of bandage contact lenses. There was no statistically significant difference in epithelial defect size between the 2 lenses at any postoperative visit. Three days postoperatively, reepithelialization was complete in 75.0% of eyes in the lotrafilcon A group and 72.7% of the eyes in the lotrafilcon B group. CONCLUSION: There were no differences in corneal reepithelialization or subjective measurements after PRK between the 2 types of silicone hydrogel bandage contact lenses.

Conductive keratoplasty for low to moderate hyperopia: 1-year results.

PURPOSE To assess the safety, efficacy, and stability of conductive keratoplasty in the treatment of low to moderate hyperopia and evaluate the impact of the procedure on the quality of vision. METHODS Thirty-six eyes (25 patients; 13 female and 12 male) were treated for hyperopia up to +3.25 D with a Refractec ViewPoint CK system and followed for 1 year. Mean age was 50.2 +/- 8.7 years (range 31 to 71). RESULTS Before surgery, mean spherical equivalent refraction was +1.90 +/- 0.60 D (range +1.00 to +3.25 D), decreasing at 1 year after conductive keratoplasty to -0.06 +/- 0.80 D, and was within +/- 0.50 D of emmetropia in 68% (24 eyes) and within +/- 2.00 D in all eyes. Twelve months after conductive keratoplasty, uncorrected visual acuity was 20/20 or better in 19 eyes (50%) and 20/40 or better in 32 eyes (89%). No eye lost > or = 2 Snellen lines or had induced cylinder > or = 2.00 D. The mean root mean square values for higher order optical aberrations were 0.060 +/- 0.039 before and 0.174 +/- 0.170 at 3 months after surgery. No statistically significant changes in contrast sensitivity were noted. CONCLUSIONS Conductive keratoplasty for low to moderate hyperopia provided safe, effective, and stable results both in refraction and quality of vision.

LASIK Flap Characteristics Using the Moria M2 Microkeratome With the 90-µm Single Use Head

PURPOSE To evaluate the accuracy and consistency of corneal flap thickness, horizontal diameter, and hinge size with the Moria M2 90-microm single use head. METHODS Fifty-two myopic patients (104 eyes), mean age 32.6 years, underwent bilateral LASIK with a superior hinged flap using the Moria M2 microkeratome (90-microm single use head). Prospective evaluation included flap thickness (subtraction method), diameter, hinge size, interface particles, intraoperative complications, and visual recovery. RESULTS The mean preoperative spherical equivalent refraction was -5.72 +/- 2.59 diopters (D) (range: -2.88 to -10.75 D) and -5.84 +/- 2.73 D (range: -3.13 to -9.38 D) for right and left eyes, respectively. The mean preoperative central corneal thickness was 548 +/- 24 microm and 547 +/- 25 microm for right and left eyes, respectively. The mean preoperative steepest K was 44.12 +/- 1.28 D and 44.41 +/- 1.27 D for right and left eyes, respectively. Corneal diameter (white-to-white) was 12 +/- 0.4 mm and 11.9 +/- 0.4 mm for right and left eyes, respectively. The mean postoperative flap thickness was 109 +/- 18 microm (range: 67 to 152 microm) and 103 +/- 15 microm (range: 65 to 151 microm) for right and left eyes, respectively. The mean postoperative flap diameter was 9.4 +/- 0.3 mm (expected mean according to the nomogram given by the company was 9.5 mm). The mean postoperative hinge chord was 4.4 +/- 0.4 mm (expected mean 4.2 mm). No interface particles were detected on slit-lamp examination. CONCLUSIONS The Moria M2 90-microm single use head is safe with reasonable predictability for LASIK flap creation.

Treatment of corneal dellen with a large diameter soft contact lens

A 58-year-old man presented with corneal dellen twelve days after pterygium removal on his left eye. Initial treatment with lubrication and artificial tears was unsuccessful. The fitting of a conventional contact lens was not possible because of conjuctival chemosis. Additionally the patient denied eye patching due to professional reasons. As an alternative treatment a large diameter bandage soft contact lens approved for extended wear was applied ((David Thomas Contact Lens T74/85 Extended Wear/Bandage of 18mm diameter). The next day corneal dellen had already began to retreat and four days later the contact lens was removed since there was no sign of dellen in the slit lamp examination. In conclusion, the use of a large diameter soft contact lens was an effective alternative solution for the treatment of corneal dellen in our patient.

Intraocular Pressure Measurements After Conductive Keratoplasty

PURPOSE To determine the possible impact of conductive keratoplasty (CK) on intraocular pressure (IOP) measurements. METHODS A prospective, single-center, noncomparative interventional case series was performed. Baseline and postoperative IOPs were measured by Goldmann applanation tonometry in 32 eyes of 18 patients who underwent CK for hyperopia correction. Mean follow-up was 11.9 months (range: 8 to 18 months). RESULTS After CK, a statistically significant decrease in the measured IOP was observed (before CK: 14.22+/-1.64 vs after CK: 12.66+/-2.21, P<.001). The change in IOP readings postoperatively was not correlated with age, sex, keratometric readings, or attempted correction. CONCLUSIONS Despite the limitations due to the small number of patients enrolled in this study, the applanation tonometer appears to underestimate the true IOP after CK.