Corneal collagen cross-linking for the treatment of progressive keratoconus: 3-year prospective outcome.

OBJECTIVE: To assess the long-term effects of treatment of progressive keratoconus with ultraviolet A-riboflavin collagen cross-linking (CXL). DESIGN: This was a prospective clinical study. PARTICIPANTS: Seventeen eyes of 17 patients with progressive keratoconus were treated with CXL. METHODS: Patients were examined preoperatively, at week 1, months 1, 3, 6, 9, 12, 24, and 36 after treatment. We assessed uncorrected visual acuity (UCVA) and best spectacle-corrected visual acuity (BSCVA), refraction, biomicroscopy and fundus appearance, intraocular pressure, endothelial cell density (ECD), corneal topography, minimal corneal thickness (MCT), macular optical coherence tomography, axial length, and corneal biomechanics with the ocular response analyzer. RESULTS: Comparing the 36-month time point results with pretreatment values, we found that UCVA and BSCVA were unchanged. Steepest meridian keratometry (D) and mean cylinder (D) did not show significant change compared with pretreatment values but showed a slight increase as compared with the 24-month time point (53.9 vs 51.7 vs 52.5, and 10.5 vs 8.1 vs 9.2 before, at 24 months, and at 36 months, respectively). Axial length (mm) showed an elongation trend throughout the follow-up period (24.56 vs 24.61 [p = 0.04] vs 24.71 [p = 0.05], before, at 24 months, and at 36 months, respectively). No significant change was observed in ECD, corneal hysteresis and corneal resistance factor, MCT, or foveal thickness. CONCLUSIONS: Three-year results after CXL show stable visual acuity, stable corneal thickness, and stable corneal biomechanical parameters. The decreasing trend in keratometry values that was observed during the first 2 years after CXL was no longer evident. Longer follow-up is needed to decide whether it is a first sign of loss of achieved stability and resumption of keratoconus progression.

Clinical and corneal biomechanical changes after collagen cross-linking with riboflavin and UV irradiation in patients with progressive keratoconus: results after 2 years of follow-up.

PURPOSE: To assess the biomechanical and keratometric effects and the safety of treatment of progressive keratoconus with UV-riboflavin collagen cross-linking (CXL). METHODS: This is a prospective clinical controlled study. Fourteen eyes of 14 patients with progressive keratoconus were treated with CXL after corneal deepithelization. Patients were assessed preoperatively, at week 1 and at months 1, 3, 6, 9, 12, and 24 after treatment. We measured uncorrected visual acuity (UCVA) and best spectacle-corrected visual acuity (BSCVA) (logarithm of the minimum angle of resolution), refraction, biomicroscopy and fundus examination, intraocular pressure, axial length, endothelial cell density, corneal topography, minimal corneal thickness, macular optical coherence tomography, and corneal biomechanics with the ocular response analyzer. RESULTS: Comparing the preoperative results with 24-month postoperative results, we observed significant improvement in BCVA (0.21 ± 0.1 to 0.14 ± 0.1, P = 0.002) and stability in UCVA (0.62 ± 0.5 and 0.81 ± 0.49, P = 0.475). We observed a significant decrease in steepest-meridian keratometry (diopters) (53.9 ± 5.9 to 51.5 ± 5.4, P = 0.001) and in mean cylinder (diopters) (10.2 ± 4.1 to 8.1 ± 3.4, P = 0.001). Significant elongation of the eyes was observed, from 24.39 ± 1.7 mm to 24.71 ± 1.9 mm (P = 0.007). No significant change was observed in mean simulated keratometry, minimal corneal thickness, endothelial cell density, corneal hysteresis, and corneal resistance factor or foveal thickness. CONCLUSIONS: Two years after CXL, the observation of stable UCVA, improved BCVA, and reduced keratometry suggests stabilization in progression of keratoconus. Unchanged corneal thickness, endothelial cell density, and foveal thickness suggest the long-term safety of this procedure. The observed increase in axial length and stability in corneal biomechanical parameters measured with the ocular response analyzer require further study for verification and explanation.

Variations in corneal biomechanical parameters and central corneal thickness during the menstrual cycle.

PURPOSE: To assess variations in the biomechanical properties and central corneal thickness (CCT) throughout the female menstrual cycle. SETTING: Department of Ophthalmology, Assaf Harofeh Medical Center, Zerifin Israel. DESIGN: Case series. METHODS: Young healthy women were prospectively recruited. Every participant was assessed at the beginning of the menstrual cycle, at ovulation, and at the end of the cycle. At every time point, corneal hysteresis (CH) and the corneal resistance factor (CRF) were measured with the Ocular Response Analyzer and the CCT was measured with an ultrasonic pachymeter. RESULTS: Twenty-two eyes of 22 women (mean age 19.5 years ± 1.5 [SD]) were included. The CH was statistically significantly decreased at ovulation (10.1 mm Hg) compared with the beginning (11.1 mm Hg, P<.001) and the end (11.4 mm Hg, P<.001) of the cycle. The CRF was also significantly decreased at ovulation (9.8 mm Hg) compared with the beginning (10.6 mm Hg, P<.001) and the end (10.5 mm Hg, P<.001) of the cycle. The central cornea was thinnest at the beginning (535 µm) and statistically significantly thicker at ovulation (542 µm, P<.001) and at the end of the menstrual cycle (543 µm, P<.001). CONCLUSIONS: The CCT and biomechanical parameters significantly varied during the menstrual cycle. The CH and CRF were temporarily decreased at ovulation. The cornea was thinnest at the beginning and thicker at ovulation and at the end of the cycle. Such corneal changes may be important to consider during screening of candidates for laser refractive surgery.

Femtosecond thin-flap LASIK for the correction of ametropia after penetrating keratoplasty.

PURPOSE: To evaluate the outcomes of LASIK with thin femtosecond laser flaps for the treatment of refractive errors after penetrating keratoplasty (PK). METHODS: Eleven consecutive eyes underwent femtosecond thin-flap LASIK 51.6+/-42.1 months (range: 13 to 156 months) after the initial PK. A full ophthalmic assessment was performed before femtosecond LASIK and 6 months after surgery. Postoperative retreatments were also noted. RESULTS: No intra- or postoperative complications were observed. The outcomes of nine eyes that completed at least 6 months' follow-up and had no retreatment during that period were evaluated. Mean preoperative myopia decreased from -3.60+/-1.60 diopters (D) to +1.00+/-2.70 D 6 months after surgery, and mean hyperopia decreased from +3.50+/-1.30 D preoperatively to +0.30+/-0.70 D 6 months after surgery. Mean preoperative astigmatism decreased from -6.60+/-3.60 D to -2.90+/-2.00 D 6 months after surgery. At 6 months, the mean preoperative myopic spherical equivalent refraction (SE) decreased from -6.40+/-2.00 D to -0.02+/-2.20 D, and mean hyperopic SE from +0.80+/-2.80 D to -0.60+/-0.60 D. At 6 months postoperatively, 67% (6/9) of eyes were within 1 line of preoperative best spectacle-corrected visual acuity and 33% (3/9) gained > or =2 lines. CONCLUSIONS: Femtosecond thin-flap LASIK is a safe procedure in eyes with previous PK. This procedure is reasonably predictable, especially for the spherical component of the refraction. Creating the flap with the femtosecond laser and performing excimer laser ablation within the corneal graft limits without involving the graft-host junction provides the advantage of performing the entire procedure in one step.

Effect of thin femtosecond LASIK flaps on corneal sensitivity and tear function.

PURPOSE: To evaluate changes in comeal sensitivity and tear function following myopic LASIK with thin femtosecond flaps. METHODS: A retrospective study was performed to compare corneal sensitivity (filament), tear breakup time, and anesthetized Schirmer test preoperatively and at 1 week and 2 and 6 months postoperatively. RESULTS: Seventy-two eyes of 38 consecutive patients (20 women and 18 men) who underwent LASIK for myopia or myopic astigmatism with thin femtosecond flaps (IntraLase femtosecond laser system and Technolas 217 PlanoScan V2.9992 or wavefront-guided Zyoptix 3.1 excimer laser) were evaluated. Preoperative mean corneal sensitivity was 5.3+/-1.5 mm, which decreased to 4.6+/-1.7 mm at 1 week, increased to 5.0+/-1.3 mm at 2 months, and returned to baseline values at 6 months postoperatively. Mean Schirmer score was 13.7+/-5.7 mm preoperatively and 12.1+/-5.1, 13.1+/-4.8, and 13.0+/-5.1 mm at 1 week and 2 and 6 months postoperatively, respectively. Mean tear breakup time was 7.7+/-2.6 seconds preoperatively and 7.8+/-3.5, 9.2+/-4.6, and 8.8+/-4.5 seconds at 1 week and 2 and 6 months postoperatively, respectively. No significant increase in fluorescein staining was observed throughout follow-up. CONCLUSIONS: Reductions in corneal sensitivity and tear function tests were minimal after myopic LASIK with thin femtosecond flaps. Despite the relatively narrow hinge, the thin, uniform femtosecond flap does not appear to have an adverse effect on corneal sensitivity and dry eye signs at 6 months postoperatively.

Refractive eye surgery in treating functional amblyopia in children.

PURPOSE: While excimer laser refractive surgery is recommended and highly successful for correcting refractive errors in adults, its use in children has not been extensively exercised or studied. We report our experience treating children with amblyopia due to high anisometropia, high astigmatism, high myopia and with associated developmental delay. SETTING: Review of patient records of our refractive clinic. METHODS: A retrospective review was made of all 11 children with stable refractive errors who were unsuccessfully treated non-surgically and then underwent corneal refractive surgery and in one case, lenticular surgery. Seven had high myopic anisometropia, 2 had high astigmatism, and two had high myopia--one with Down's Syndrome and one with agenesis of the corpus callosum. RESULTS: The surgical refractive treatment eliminated or reduced the anisometropia, reduced the astigmatic error, improved vision and improved the daily function of the children with developmental delay. There were no complications or untoward results. CONCLUSIONS: Refractive surgery is safe and effective in treating children with high myopic anisometropia, high astigmatism, high myopia and developmental delay due to the resulting poor vision. Surgery can improve visual acuity in amblyopia not responding to routine treatment by correcting the refractive error and refractive aberrations.

Laser in situ keratomileusis in myopic patients with congenital nystagmus.

PURPOSE: To evaluate the results of laser in situ keratomileusis (LASIK) and IntraLASIK in the treatment of myopic patients with nystagmus. METHODS: Eight patients with congenital nystagmus (16 eyes), aged 23 to 49 years, had LASIK surgery. Corneal flaps were created using the Bausch & Lomb Hansatome microkeratome or the IntraLase femtosecond laser. The ablations were performed with the Bausch & Lomb excimer laser with an active tracking system. In some patients, the eyes were fixated with forceps or a fixation ring during laser ablation. RESULTS: The refractive errors were corrected in all cases. There was no decentration or loss of best corrected visual acuity greater than 1 line. In 56% of the eyes, the postoperative uncorrected visual acuity was better than the best spectacle-corrected visual acuity (BSCVA). The BSCVA improved in 62.5% of the eyes. The overall visual performance improved in all patients. One patient who did not drive before surgery became eligible for a driver's license after surgery. CONCLUSIONS: Selected patients with myopia and congenital nystagmus may benefit from laser refractive surgery. Laser refractive surgery may be safely and accurately performed using the Hansatome microkeratome or the IntraLase femtosecond laser and an active tracking system with or without mechanical fixation. The BSCVA may improve in certain patients postoperatively.

[Wavefront-guided lasek after intacs in eyes with stable keratoconus].

BACKGROUND: Keratoconus is a non-inflammatory, progressive thinning disorder of the cornea, resulting in a typical protrusion and in refractive errors and low visual acuity. Many of the patients with stable keratoconus encounter difficulties wearing glasses or contact lenses. PURPOSE: To evaluate the results of wave-front guided laser assisted subepithelial keratectomy (LASEK) for the correction of residual spherical and spherocylindrical myopia after INTACS insertion in patients with stable keratoconus. METHODS: Four eyes of keratoconus patents were treated with Zyoptix wavefront-guided LASEK for correction of residual myopia and astigmatism after insertion of INTACS. The refraction after insertion of INTACS was stable at least six months before the Zyoptix-LASEK. The mean pre-INTACS refraction was myopia of -2.37 D (range 0 to - 5.00 D) and astigmatism of -3.93 D (range -1.00 to -7.5 D). The mean refraction prior to Zyoptix-LASEK was myopia of -0.2 D and astigmatism of -2.71 D. The mean follow-up period after the Zyoptix LASEK was 8 months. RESULTS: Initially, prior to both surgeries, the mean uncorrected visual acuity was 6/240 (range count-fingers to 6/60) and at the final postoperative visit 6/12 (range 6/10 to 6/ 18). The preoperative mean best spectacle corrected visual acuity was 6/15 (range 6/10 to 6/24) and at the final postoperative follow-up visit 6/9 (range 6/8.5 to 6/12). CONCLUSION: Zyoptix wavefront-guided LASEK for correction of residual myopia and astigmatism in keratoconus patients after INTACS insertion and stable refraction provided excellent visual outcome, with no loss of visual acuity and no complications.

[Lasik in myopic patients with congenital nystagmus].

PURPOSE: To present the results of IntraLASIK treatment in myopic patients with nystagmus. METHODS: Four patients, ranging in age from 25 to 49 years, with congenital nystagmus (8 eyes), underwent IntraLASIK surgery. Corneal flaps were made by Intralase femtosecond laser. In some patients, the eyes were fixated with forceps or a fixation ring during the laser ablation. In all patients, the effect of involuntary eye movements was neutralized by an active tracking system. RESULTS: The refractive errors were corrected in all cases. There was no decentration or loss of best corrected visual acuity by more than 1 line. In 3 of 8 eyes, the post-operative uncorrected visual acuity (UCVA) was equal or better than the best spectacles corrected visual acuity (BSCVA) preoperatively. Four of the 8 eyes retained or improved their BSCVA. CONCLUSIONS: Some patients with myopia and nystagmus may benefit from laser refractive surgery. By using the Intralase femtosecond laser and an active tracking system with or without mechanical fixation, laser refractive surgery may be safely and accurately performed in selected cases of nystagmus. Certain patients improve their BSCVA postoperatively.

Clinical outcome of wavefront-guided laser in situ keratomileusis in eyes with moderate to high myopia with thin corneas.

PURPOSE: To evaluate the clinical outcome of wavefront-guided laser in situ keratomileusis (LASIK) for the treatment of moderate to high myopia associated with a thin cornea. SETTING: Enaim Laser Medical Center, Tel Aviv, Israel. METHODS: This retrospective study included 98 eyes of 49 patients with moderate to high myopia (-5.20 to -10.35 diopters [D]) and thin corneas (456 to 498 mum) treated with wavefront-guided LASIK (Zyoptix, Bausch & Lomb) and followed for 36 months. Preoperative wavefront analysis was performed with a Hartmann-Shack aberrometer, and treatment was performed with the Technolas 217 z excimer laser system (Bausch & Lomb). Final refraction data, uncorrected visual acuity (UCVA), best corrected visual acuity (BCVA), optic zone size, ablation depth, optical aberrations, and night glare complaints were evaluated. RESULTS: Mean patient age was 28 years +/- 7 (SD), and mean preoperative spherical equivalent refraction was -7.06 D (range -5.20 to -10.35 D). Final UCVA ranged between 6/6 and 6/30. The safety index of the technique was 1.03, and the efficacy index was 0.67. Undercorrection of more than 0.50 D was observed in 41.3% of the high-myopic eyes (-7.00 to -10.35 D, n = 58) compared with 10% in the moderately myopic eyes (-5.00 to -6.75 D, n = 40). A significant reduction in spherical aberration (Z(4)0) was found 12 months postoperatively in all eyes. Night glare was documented in 4 eyes (4%) in the high myopia group. There were no cases of corneal ectasia. CONCLUSION: Zyoptix was safe in eyes with moderate to high myopia with relatively thin corneas (<498 microm). For myopia between -7.00 D and -10.35 D, a small optical zone (4.3 to 5.6 mm) may be applied as night glare was relatively rare, but significant undercorrection should be expected.

Laser in situ keratomileusis for correction of myopia in eyes after retinal detachment surgery.

PURPOSE: To evaluate the safety and efficacy of laser in situ keratomileusis (LASIK) for correction of myopia in eyes with previous retinal detachment surgery. METHODS: A retrospective review was conducted of all consecutive eyes that underwent LASIK after retinal detachment surgery. Data was collected regarding previous ocular surgery and its time prior to LASIK, intra- and postoperative complications, and visual outcome measures pre- and postoperatively. RESULTS: Ten eyes with previous retinal detachment surgery were scheduled for LASIK. One eye was excluded from data analysis as LASIK was aborted due to inadequate microkeratome suction because of conjunctival scarring. Nine eyes underwent an uneventful LASIK procedure. On average, LASIK was performed 130+/-123 months following retinal detachment surgery. Postoperative LASIK follow-up was 14.8+/-12.5 months. No significant intraoperative, postoperative, or retinal complications were observed. The mean preoperative spherical equivalent refraction was -9.00+/-3.00 diopters (D), uncorrected visual acuity (UCVA) was 0.06+/-0.02, and best spectacle-corrected visual acuity (BSCVA) was 0.64+/-0.16. At the end of follow-up, the mean spherical equivalent refraction was 0.65+/-0.88 D, mean UCVA was 0.57+/-0.14, and mean BSCVA was 0.72+/-0.19. Differences between BSCVA before and after LASIK were statistically significant (P=.038). At final follow-up, the safety index was 1.22 and efficacy index was 1.01. CONCLUSIONS: Laser in situ keratomileusis was found to be a safe and efficient option for treating refractive errors in eyes with previous retinal detachment surgery.

Single Intacs segment for post-laser in situ keratomileusis keratectasia.

PURPOSE: To describe the visual outcome of implantation of a single Intacs segment (Addition Technology Inc.) in eyes with keratectasia after myopic laser in situ keratomileusis (LASIK). SETTING: Private refractive surgery center, Jerusalem, Israel. METHODS: This retrospective, noncomparative, interventional, consecutive, small case series studied 5 eyes of 5 patients with post-LASIK keratectasia from 3 refractive laser centers treated by Intacs implantation. Before and 9 months after Intacs implantation, the uncorrected visual acuity (UCVA), best spectacle-corrected visual acuity (BSCVA), manifest refraction, keratometry, videokeratography, inferior-superior asymmetry, and patient questionnaires about visual function were assessed. RESULTS: Intacs implantation was performed 17 to 32 months post LASIK with no intraoperative complications and no loss of visual acuity. After implantation, the UCVA improved 8, 4, 3, 0.5, and 5 lines and the BSCVA, 2, 2.5, 1, 0.5, and 2 lines. The mean manifest refraction spherical equivalent improved from -1.60 diopters (D) +/- 1.67 (SD) to -0.80 +/- 1.05 D. The mean manifest astigmatic correction decreased from -3.9 +/- 2.96 to -2.46 +/- 2.77 D. Corneal topography showed improved inferior steepening and less irregular astigmatism. The mean inferior-superior asymmetry improved from 7.88 +/- 4.59 to 2.46 +/- 2.77 D. Self-reported visual symptoms improved significantly in Cases 1, 2, and 5 and slightly in Cases 3 and 4. CONCLUSIONS: Implantation of a single Intacs segment inferiorly appeared to improve progressive myopia and regular and irregular astigmatism in eyes with corneal ectasia after LASIK. With further study, this technique may prove to be an effective, relatively noninvasive approach.

Laser in situ keratomileusis improves visual acuity in some adult eyes with amblyopia.

PURPOSE: To report the results of laser in situ keratomileusis (LASIK) in a series of adult patients with amblyopia. METHODS: A retrospective noncomparative review was performed on patients with amblyopia who underwent LASIK for correction of ametropia, using the Summit Krumeich Barraquer microkeratome and the Nidek EC-5000 excimer laser. Data were collected on uncorrected visual acuity, best spectacle-corrected visual acuity, manifest refraction, anterior segment evaluation, intraocular pressure, corneal topography, and dilated fundus examination (preoperative and postoperatively on day 1, months 2 and 6). RESULTS: Eight eyes of seven patients were included, with a mean patient age of 30 +/- 10 years (range 21 to 49 yr). Mean preoperative spherical equivalent refraction was -4.70 D (range -12.62 to +4.71 D) and the best spectacle-corrected visual acuity varied from 20/32 to 20/80. At 2 months after LASIK, mean spherical equivalent refraction was -0.37 +/- 0.60 D (range -1.37 to + 0.60 D), uncorrected visual acuity ranged between 20/20 to 20/30, and a mean gain of 3 Snellen lines (range 2 to 4 lines) was observed. All patients reported significant subjective improvement in their perception of vision. The visual acuity and subjective improvement were maintained throughout 6 months postoperatively. CONCLUSIONS: LASIK with the Nidek EC-5000 laser for correction of ametropia in adult amblyopic eyes provided encouraging results for visual acuity improvement beyond correction of the refractive error.

Phototherapeutic keratectomy with mitomycin C for corneal haze following photorefractive keratectomy for myopia.

PURPOSE: To evaluate the safety and efficacy of phototherapeutic keratectomy (PTK) with single application of mitomycin C for patients with severe corneal haze following photorefractive keratectomy (PRK) for high myopia. METHODS: Eight eyes of seven patients were treated with PTK and intraoperative topical application of mitomycin C (0.02%) for severe corneal haze (grade 3) following PRK for myopia. RESULTS: All patients' visual performance improved significantly. Mean preoperative visual acuity (20/200 for both UCVA and BSCVA) improved significantly to 20/33 (0.6) and 20/30 (0.7) for UCVA and BSCVA, respectively. Six eyes (85.7%) had improved UCVA to 20/40 or better and gained five or more lines of UCVA. The corneal haze score decreased from grade 3 initially (for all eyes prior to PTK and mitomycin C) to a final mean haze score of 0.3 (range 0 to 0.5). Mean final spherical equivalent refraction achieved was -1.30 +/- 1.60 D (range -3.75 to +1.25 D). One eye gained only three lines of visual acuity due to regression and residual haze. No adverse effects related to the use of mitomycin C were recorded. CONCLUSION: PTK with a single intraoperative application of mitomycin C was safe and effective in reducing corneal haze and improving visual acuity in patients with severe corneal haze following PRK.