Sequential Custom Therapeutic Keratectomy for the Treatment of Granular Corneal Dystrophy Type 1: A Long-term Study.

PURPOSE: To evaluate the effectiveness of sequential custom phototherapeutic keratectomy (SCTK) for granular corneal dystrophy type 1 (GCD1). METHODS: Thirty-seven eyes of 21 patients with GCD1 were treated with SCTK to remove superficial opacifications, regularize the corneal surface, and decrease optical aberrations. SCTK is a sequence of custom therapeutic excimer laser keratectomies with step-by-step intraoperative corneal topography monitoring of results. Six eyes of 5 patients previously treated with penetrating keratoplasty received SCTK for disease recurrence. Pre-operative and postoperative corrected distance visual acuity (CDVA), refractive values, mean pupillary keratometry, and pachymetry were retrospectively analyzed. The mean follow-up period was 41.3 months. RESULTS: SCTK provided significant decimal CDVA improvement, from 0.33 ± 0.22 to 0.63 ± 0.24 (P < .0001) at the last available follow-up visit. One eye, initially treated with penetrating keratoplasty, showed visually significant disease 8 years after the first SCTK and was re-treated. Mean corneal pachymetry difference between preoperative and final follow-up values was 78.42 ± 62.26 µm. Mean corneal curvature and the spherical component did not show a statistically significant change or hyperopic shift. Astigmatism and higher order aberration reduction were statistically significant. CONCLUSIONS: SCTK is a powerful tool for the treatment of anterior corneal pathologies hindering vision and quality of life, such as GCD1. SCTK is less invasive and fosters more rapid visual recovery than penetrating keratoplasty or deep anterior lamellar keratoplasty. Providing significant visual improvement, SCTK can be the preferred initial treatment in eyes with GCD1. [J Refract Surg. 2023;39(6):422-429.].

Sequential Customized Therapeutic Keratectomy for Reis-Bücklers' Corneal Dystrophy: Long-term Follow-up.

PURPOSE: To report long-term outcomes of sequential customized therapeutic keratectomy for Reis-Bücklers' corneal dystrophy. METHODS: This was a retrospective review of 14 eyes of 8 patients with Reis-Bücklers' corneal dystrophy that underwent surgical peeling with a spatula of the epithelium and subepithelial membrane present in Reis-Bücklers' corneal dystrophy, with subsequent sequential customized therapeutic keratectomy featuring a multi-step approach with sequential, repeated customized excimer laser photoablations alternating with repeat intraoperative topographies to monitor and progressively reduce corneal irregularities. RESULTS: At the last follow-up of 5.09 ± 4.67 years (range: 0.29 to 12.87 years), mean corrected distance visual acuity improved from 20/50 (range: 20/630 to 20/30) to 20/25 (range: 20/20 to 20/40) (P < .01), whereas mean refraction changed from -0.29 ± 1.91 diopters (D) sphere and -0.75 ± 0.81 D cylinder preoperatively to 1.25 ± 2.10 D sphere and -1.08 ± 0.53 D cylinder postoperatively. Mean central keratometry values changed minimally from 42.67 ± 2.26 D preoperatively to 42.65 ± 2.30 D postoperatively. Coma significantly decreased from 0.60 ± 0.40 to 0.35 ± 0.28 µm (P < .05), whereas total higher order aberrations, spherical aberration, and trefoil remained stable. No patient underwent corneal transplantation. Disease recurrence required re-treatment using the same protocol in 14.28% of eyes (n = 2) for a mean of 5.86 ± 0.31 years (range: 5.64 to 6.08 years) after initial surgery. CONCLUSIONS: Five years after sequential customized therapeutic keratectomy, most eyes with Reis-Bücklers' corneal dystrophy showed improved visual acuity, stable refraction, and improved or stable higher order aberrations. [J Refract Surg. 2018;34(10):682-688.].

Corneal Apical Scar After Hyperopic Excimer Laser Refractive Surgery: Long-term Follow-up of Treatment With Sequential Customized Therapeutic Keratectomy.

PURPOSE: To evaluate long-term results of sequential customized therapeutic keratectomy (SCTK) in highly aberrated corneas with apical scars consequent to hyperopic excimer laser refractive surgery. METHODS: Fifteen eyes of 12 patients treated with SCTK for a corneal apical scar after hyperopic excimer laser refractive surgery were retrospectively evaluated. SCTK is a sequence of custom therapeutic excimer laser keratectomies where the results are monitored step-by-step by intraoperative corneal topography. In the preoperative and postoperative course, corrected distance visual acuity (CDVA), corneal topography and aberrometry, Scheimpflug tomography, and anterior segment optical coherence tomography were compared before and after SCTK. RESULTS: The postoperative follow-up comprised 7 patients with 1 year and 8 patients with more than 2 years of follow-up. Functional results showed a significant increase of CDVA from 0.36 ± 0.31 to 0.14 ± 0.25 logMAR at the last available follow-up. Mean sphere did not change significantly from the baseline, demonstrating that SCTK does not induce hyperopic shift. Higher order aberrations decreased significantly from 2.57 ± 1.92 to 0.80 ± 0.42 µm at the last follow-up. Topographic indexes (irregular astigmatism index, surface asymmetry index, and surface regularity index) showed a significant improvement after SCTK. Pachymetry 3 months postoperatively showed no significant reduction during the entire follow-up in either minimum or central thickness. CONCLUSIONS: Long-term results demonstrate that SCTK can treat this sight-threatening complication of hyperopic excimer laser refractive surgery, achieving significant improvements in visual acuity and in many corneal morphological parameters. [J Refract Surg. 2018;34(2):113-120.].

Advanced Surface Ablation With a New Software for the Reduction of Ablation Irregularities.

PURPOSE: To compare visual outcomes and postoperative aberrations after surface ablation performed with a 750-Hz versus a 1,050-Hz excimer laser coupled with an ablation software designed to reduce corneal surface irregularity. METHODS: Retrospective comparative trial of myopic eyes that had refractive surgery consecutively treated with transepithelial advanced surface ablation with a 750-Hz excimer laser (750 group) versus a 1,050-Hz excimer laser coupled with the Smart Pulse Technology ablation software (SPT group). The SPT algorithm is a laser pulse technology software aimed at reducing surface irregularity of the stromal bed at the end of treatment. The authors evaluated the effect of this smoothing on final visual acuity. Patients were observed for 6 months. RESULTS: A total of 139 eyes in the 750 group and 40 eyes in the SPT group were evaluated. Epidemiological and preoperative refractive data of the two groups were comparable. Uncorrected distance visual acuity improved with time and was significantly better in the SPT group (-0.04 ± 0.61 logMAR for the SPT group vs 0.02 ± 0.78 logMAR for the 750 group) (P < .001). At 6 months, 55% versus 21% achieved 20/16 or better (P = .005) and 90% versus 65% achieved 20/20 or better (P = .019) visual acuity in the SPT and 750 groups, respectively. Corrected distance visual acuity improved with time and appeared to be influenced by group (P = .054), with better results in the SPT group. Coma and trefoil improved significantly with time in a similar manner in both groups. CONCLUSIONS: Surface ablation with the 1,050-Hz excimer laser and SPT software, aimed at reducing the final superficial stromal irregularity, led to improvement of 6-month uncorrected visual acuity. [J Refract Surg. 2017;33(2):89-95.].

Transepithelial iontophoresis corneal collagen cross-linking for progressive keratoconus: initial clinical outcomes.

PURPOSE: To report initial clinical results of transepithelial corneal collagen cross-linking with iontophoresis (I-CXL). METHODS: Twenty eyes of 20 patients diagnosed as having progressive keratoconus who underwent I-CXL were included in this prospective non-randomized clinical study. Corrected distance visual acuity (CDVA), spherical equivalent and cylinder refraction, various corneal topography and Scheimpflug tomography parameters, aberrometry, anterior segment optical coherence tomography, and endothelial cell count were assessed at baseline and at 1, 3, 6, and 12 months postoperatively. RESULTS: CDVA improved significantly at 3, 6, and 12 months postoperatively (logMAR difference of -0.07 ± 0.01, -0.09 ± 0.03, and -0.12 ± 0.06, respectively; P < .05). Aberrometry remained stable during follow-up and a trend toward improvement was noted. All topographic parameters (including maximum keratometry) were stable during the follow-up, but exhibited a positive non-significant trend toward improvement. Minimum corneal thickness values were stable for up to 12 months postoperatively. None of the patients showed a progression of keratoconus. Endothelial cell counts did not change significantly (P > .05). CONCLUSIONS: Preliminary results up to 1 year postoperatively indicate the efficacy of I-CXL in stabilizing the progression of this degenerative disease combined with significant improvement of CDVA. I-CXL, which spares the corneal epithelium, has the potential to become a valid alternative for halting the progression of keratoconus while reducing postoperative patient pain, risk of infection, and treatment time in select patients; however, the relative efficacy of this technique compared to standard epithelium-off techniques remains to be determined.

Imaging mass spectrometry by matrix-assisted laser desorption/ionization and stress-strain measurements in iontophoresis transepithelial corneal collagen cross-linking.

PURPOSE: To compare biomechanical effect, riboflavin penetration and distribution in transepithelial corneal collagen cross-linking with iontophoresis (I-CXL), with standard cross linking (S-CXL) and current transepithelial protocol (TE-CXL). MATERIALS AND METHODS: The study was divided into two different sections, considering, respectively, rabbit and human cadaver corneas. In both sections corneas were divided according to imbibition protocols and irradiation power. Imaging mass spectrometry by matrix-assisted laser desorption/ionization (MALDI-IMS) and stress-strain measurements were used. Forty-eight rabbit and twelve human cadaver corneas were evaluated. RESULTS: MALDI-IMS showed a deep riboflavin penetration throughout the corneal layers with I-CXL, with a roughly lower concentration in the deepest layers when compared to S-CXL, whereas with TE-CXL penetration was considerably less. In rabbits, there was a significant increase (by 71.9% and P = 0.05) in corneal rigidity after I-CXL, when compared to controls. In humans, corneal rigidity increase was not significantly different among the subgroups. CONCLUSIONS: In rabbits, I-CXL induced a significant increase in corneal stiffness as well as better riboflavin penetration when compared to controls and TE-CXL but not to S-CXL. Stress-strain in human corneas did not show significant differences among techniques, possibly because of the small sample size of groups. In conclusion, I-CXL could be a valid alternative to S-CXL for riboflavin delivery in CXL, preserving the epithelium.

Corneal cross-linking as a treatment for keratoconus: four-year morphologic and clinical outcomes with respect to patient age.

PURPOSE: To report the 4-year outcomes of corneal cross-linking (CXL) for progressive keratoconus in a population of different age groups. DESIGN: Retrospective, single-center, nonrandomized clinical study. PARTICIPANTS: Four hundred consecutive eyes treated with corneal CXL for progressive keratoconus from April 2006 through April 2010. INTERVENTION: After removal of the epithelium, the cornea was irrigated for 30 minutes with a solution of 0.1% riboflavin and 20% dextran, followed by irradiation with an ultraviolet A light of 3 mW/cm(2) for 30 minutes. MAIN OUTCOME MEASURES: Best-corrected visual acuity (BCVA), sphere and cylinder refraction, corneal topography, Scheimpflug tomography, and aberrometry were assessed at baseline and at 1, 6, 12, 24, 36, and 48 months after corneal CXL treatment. The compiled data were stratified according to age (group A, younger than 18 years; group B, 18-29 years; group C, 30-39 years; and group D, older than 40 years). RESULTS: Comparative analysis included 400 eyes of 301 patients. Functional results showed a significant increase in BCVA in group A by a mean reduction of -0.11 logarithm of the minimum angle of resolution (logMAR) after 12 months, in group B by a mean reduction of -0.31 logMAR after 36 months, in group C by a mean reduction of -0.33 logMAR after 36 months, and in group D by a mean reduction of -0.26 logMAR after 36 months. Morphologic results showed an analogous regularization of corneal shape with a significant reduction of opposite sector index by a mean value of -0.53 at 12 months in group A, -1.14 at 36 months in group B, -1.10 at 36 months in group C, and -0.55 at 12 months for group D. Optical quality improvement was demonstrated by a mean significant reduction of coma -1.52 µm after 12 months in group A, -1.58 µm after 24 months in group B, -2.57 µm after 36 months for group C, and -0.25 µm after 36 months in group D. CONCLUSIONS: Outcomes stratified by age indicate the efficacy of corneal CXL in stabilizing the progression of ectatic disease in all age groups and improving the functional and morphologic parameters in select groups. Results indicated better functional and morphologic results in the population between 18 and 39 years of age. FINANCIAL DISCLOSURE(S): Proprietary or commercial disclosure may be found after the references.

Bilateral ring-shaped intrastromal opacities after corneal cross-linking for keratoconus.

PURPOSE: To report a case of bilateral, ring-shaped, intrastromal corneal opacities after corneal cross-linking (CXL) for progressive keratoconus. METHODS: A 21-year-old man with bilateral, progressive keratoconus underwent CXL with riboflavin 0.1% and ultraviolet A (UVA) light in the right eye and, 6 months later, in the left eye. RESULTS: One day after CXL, the right eye showed a sharply demarcated white ring in the corneal periphery. The ring involved the superficial stroma at 2 mm from the limbus, extended from 1 to 11 o'clock, and was 1.5-mm wide. Corneal topography showed marked central flattening. Six months after treatment, a residual, faint, ring-shaped opacity remained, with a decrease in corneal ectasia. Cross-linking was then performed in the left eye. Different ultraviolet devices were used in the two eyes. On postoperative day 1, the left eye also showed a white ring of stromal opacity. Scheimpflug imaging showed corneal stromal contraction in the zone of whitening. At final examination, >1 year after surgery, corrected visual acuity was 0.00 logMAR with cylinder of 2.00 diopters in both eyes. CONCLUSIONS: The bilateral intrastromal corneal changes were innocuous in the long-term, with preservation of good visual acuity and successful stabilization of progressive keratoconus.

Corneal collagen cross-linking for ectasia after excimer laser refractive surgery: 1-year results.

PURPOSE: To evaluate the 1-year results of corneal collagen cross-linking (CXL) in eyes with postoperative excimer laser refractive surgery corneal ectasia. METHODS: Thirteen eyes of 9 consecutive patients who had undergone excimer laser refractive surgery (photorefractive keratectomy [n = 3], LASIK [n = 10]) with resultant unstable corneal ectasia underwent CXL with photosensitizing riboflavin 0.1% solution and subsequent exposure to ultraviolet radiation. Study eyes underwent complete ophthalmologic examination, endothelial specular microscopy, corneal topography, and aberrometry as well as central pachymetry and Scheimpflug-based topo/tomography preoperatively and at 3-, 6-, and 12-month intervals. RESULTS: Best spectacle-corrected visual acuity (BSCVA) improvement was statistically significant (P < .05) beyond 6 months after surgery (improvement of 0.1 logMAR at 1 year). Mean spherical equivalent refraction and mean refractive sphere reduction (improvement of 1.40 and 1.44 diopters [D], respectively) were statistically significant (P < .05) at 6 months postoperatively. At 1 year after CXL, mean endothelial cell count and keratometry (average SimK decrease of 2.02 D) as well as Klyce and Ambrósio indices did not deteriorate. Coma and spherical aberration did not change significantly. Mean pupil center pachymetry and corneal thickness at 0 and 2 mm from the thinnest corneal point decreased significantly. CONCLUSIONS: One year after surgery, CXL appears to stabilize eyes with ectasia consequent to excimer laser refractive surgery and improve BSCVA.

Photorefractive keratectomy for primary myopia using NIDEK topography-guided customized aspheric transition zone.

PURPOSE: To report the outcomes of topography-guided photorefractive keratectomy (PRK) for the treatment of myopia with or without astigmatism using the customized aspheric transition zone (CATz) ablation algorithm. METHODS: In this study, 335 eyes underwent PRK using the NIDEK Advanced Vision Excimer laser platform (NAVEX). Mean preoperative manifest refraction spherical equivalent was -4.42+/-3.46 diopters (D) (range: -14.50 to -0.50 D). Mean preoperative sphere was -3.94+/-3.43 D (range: -13.00 to -1.00 D), and mean preoperative cylinder was -0.96+/-1.05 D (range: -5.50 to 0.00 D). Refractive outcomes out to 1 year postoperatively were analyzed. RESULTS: At least 6 months postoperatively, all eyes maintained or gained lines of best spectacle-corrected visual acuity (BSCVA). There was a 51% increase in the eyes that read 20/16 or better uncorrected compared with preoperative BSCVA. At 1 year postoperative, 252/280 (90%) eyes had BSCVA 20/20 or better. Refractive outcomes within +/-0.50 D were observed in 223/275 (81%) eyes at 3 months, 228/300 (76%) eyes at 6 months, and 187/280 (67%) eyes at 1 year. CONCLUSIONS: Topography-guided PRK using CATz for the treatment of low, moderate, and high myopia is safe, effective, and predictable.

Wavefront- versus topography-guided customized ablations with the NIDEK EC-5000 CX II in surface ablation treatment: refractive and aberrometric outcomes.

PURPOSE: To compare the long-term refractive outcomes and changes in higher order wavefront aberrations in patients undergoing photorefractive keratectomy (PRK) with topography-guided (CATz) or wavefront-guided (OPDCAT) ablation algorithm using the NIDEK Advanced Vision Excimer Laser System (NAVEX). METHODS: A retrospective 12-month follow-up study was conducted of 226 eyes undergoing PRK. The NIDEK EC-5000 CX II excimer laser and Final Fit 1.11 treatment planning software were used. Sixty-eight eyes underwent OPDCAT ablation and 158 eyes underwent CATz ablation. Mean preoperative manifest refractive spherical equivalent (MRSE) was -5.73 +/- 2.03 diopters (D) (range: -11.25 to -2.50 D) in the OPDCAT group and -3.77 +/- 3.78 D (range: -12.50 to -5.75 D) in the CATz group. RESULTS: At 12 months postoperatively, mean MRSE was 0.05 D for the OPDCAT group and plano for the CATz group. Stability was similar in both groups as were visual outcomes. No eyes lost 2 or more lines of BSCVA at 6 months postoperatively or later. Mean ocular wavefront higher order aberrations at 3 months postoperatively were 0.44 +/- 0.17 microm for the OPDCAT group and 0.55 +/- 0.27 microm for the CATz group. CONCLUSIONS: Refractive outcomes were equivalent between eyes that underwent PRK with wavefront-guided ablation and those that underwent topography-guided ablation.

Transition zone design and smoothing in custom laser-assisted subepithelial keratectomy.

PURPOSE: To evaluate the results of custom laser-assisted subepithelial keratectomy (LASEK) with a specially designed transition zone and smoothing for the treatment of refractive errors. SETTING: Department of Ophthalmology, Istituto Clinico Humanitas, Rozzano-Milan, Italy. METHODS: This prospective study involved myopic eyes having refractive surgery with the butterfly LASEK technique and the Nidek EC-5000 excimer laser. The treatment was based on the surgeon's analysis of topographic and aberrometric data provided by Final Fit ablation software, which features the Custom Aspheric Transition Zone software algorithm. After the ablation, smoothing was performed to remove corneal microirregularities. RESULTS: Fifty-five eyes of 38 patients were treated. The mean preoperative spherical equivalent (SE) refraction was -6.58 diopters (D) +/- 2.24 (SD) (range -12.13 to -1.75 D). At 1 year, the mean SE refraction was -0.26 +/- 0.79 D (range -4.00 to +0.75 D). CONCLUSION: The surface ablation technique provided satisfactory results and took into account strategies to reduce unpredictability factors such as corneal biomechanical forces, haze induced by an irregular postoperative surface, and a high curvature gradient in the transition zone.

Long-term follow-up of ultrathin corneas after surface retreatment with phototherapeutic keratectomy.

PURPOSE: To evaluate visual acuity and long-term stability after phototherapeutic keratectomy (PTK) in patients with corneal thickness less than 400 microm and cornea-related vision problems. SETTING: Department of Ophthalmology, Istituto Clinico Humanitas, Rozzano-Milan, Italy. METHODS: This retrospective study comprised 48 eyes that had PTK for complications after photorefractive keratectomy that removed more than 200 microm of tissue. Phototherapeutic keratectomy was performed with the Nidek EC-5000 excimer laser with 10 Hz frequency, intraoperative topography, and masking fluid over an ablation diameter of 10.0 mm. The follow-up was 5 years. The mean preoperative best spectacle-corrected visual acuity (BSCVA) was 0.2 +/- 0.09 (SD) with -2.53 +/- 2.34 diopters (D), and the mean pachymetry was 390 +/- 38 microm. The efficacy parameters were pachymetry and visual acuity at 1 year and the stability parameters, optical refraction, corneal curvature (calculated as the mean curvature over the entire 3.0 mm and 5.0 mm central zones), and pachymetry from 1 to 5 years. RESULTS: At 1 year, the mean BSCVA was 0.6 +/- 0.72 with -2.15 +/- 1.67 D and the mean pachymetry, 341 +/- 40 microm. At 5 years, the mean BSCVA was 0.7 +/- 0.15 with -2.33 +/- 1.12 D and the mean pachymetry, 339 +/- 48 microm. In all patients, there was an improvement of 4 or more Snellen lines. Statistical evaluation of refraction and corneal curvature values at 1 and 5 years indicated no statistically significant differences. CONCLUSIONS: After PTK in eyes with ultrathin corneas, there was significant improvement in BSCVA and long-term stability of the optical refraction, corneal curvature, and pachymetry. In selected cases, 10.0 mm ablation zone PTK may be an alternative to penetrating keratoplasty, offering long-term corneal stability.

Custom phototherapeutic keratectomy with intraoperative topography.

PURPOSE: Treatment of highly aberrated eyes with opacities or irregularities consequent to previous refractive treatment, ulcers, keratitis, trauma, or corneal dystrophies remains a challenge for refractive surgeons. We evaluated the results of custom phototherapeutic keratectomy (CPK) with intraoperative corneal topography-based aberrometry and custom ablation in highly aberrated eyes. METHODS: We prospectively evaluated eyes undergoing custom phototherapeutic keratectomy (CPK) with custom ablation for corneal opacities and/or irregularities due to previous refractive treatment, keratitis, trauma, or dystrophies. Customization was planned according to corneal topography-based aberrometry, performed intraoperatively after removal of corneal epithelium. RESULTS: We treated 35 eyes of 34 patients. Mean preoperative haze was 1.6 +/- 1.4 in eyes with previous refractive surgery. Mean preoperative pachymetry was 425.7 +/- 119.3 microm. Mean preoperative spherical equivalent refraction was -1.60 +/- 3.65 D ranging from -9.38 to +10.00 D. No eye reached 20/15 best spectacle-corrected visual acuity (BSCVA), and only 63% could see 20/30 BSCVA. At final 6-month examination, mean spherical equivalent refraction was -0.71 +/- 4.01 D, ranging from -11.25 to +5.25 D. All eyes reached 20/30 or better BSCVA, and 19% had 20/15 or better BSCVA. CONCLUSIONS: Intraoperative, epithelium-free topography-based corneal aberrometry proved to be a feasible option for custom ablation in highly aberrated eyes. This approach widens the applications of PTK, providing a new procedure, custom PTK, that can be a successful solution for eyes that would otherwise require penetrating keratoplasty.

One-year results of custom laser epithelial keratomileusis with the Nidek system.

PURPOSE: To evaluate long-term results of custom laser epithelial keratomileusis (LASEK) for correction of myopia and hyperopia using the Custom Ablation Transition Zone (CATz) software and hyaluronic acid masking fluid (Laservis) for final corneal smoothing. METHODS: We conducted a prospective study of 297 eyes of 167 patients. All eyes had LASEK for correction of myopia or hyperopia. The Nidek EC-5000 excimer laser, FinalFit software, and CATz ablation profile was used in all eyes. Laservis was used as masking fluid to remove corneal micro-irregularities during the final phase of the treatment. RESULTS: Mean preoperative spherical equivalent refraction was -5.46 +/- 2.57 D (range -14.13 to +3.50 D). At 1 year after LASEK, mean spherical equivalent refraction was -0.15 +/- 0.50 D (range -4.00 D to +1.00 D). CONCLUSIONS: LASEK with the Nidek EC-5000 excimer laser, FinalFit and Custom Ablation Transition Zone (CATz) software, with corneal smoothing, was safe and effective at 1 year after surgery.

One-year follow-up of custom phototherapeutic keratectomy.

PURPOSE: Phototherapeutic keratectomy is a safe and effective treatment for many superficial diseases of the cornea. We applied intraoperative, epithelium-free, topography-based corneal aberrometry as a basis for custom phototherapeutic keratectomy (CPK) in highly aberrated eyes with opacities or irregularities consequent to previous refractive treatment, ulcers, keratitis, trauma or corneal dystrophies. METHODS: We evaluated eyes undergoing CPK for corneal opacities and or irregularities due to previous refractive treatment, keratitis, trauma, or corneal dystrophies, and treated 52 eyes of 50 patients. Customization was based on corneal topography-based aberrometry, performed intraoperatively after removal of corneal epithelium. Results were evaluated immediately and subsequent cycles of CPK were applied when necessary. Eyes were followed for 1 year. RESULTS: For the 52 eyes of 50 patients, mean preoperative haze was of 1.7 +/- 1.47 in eyes with previous refractive surgery. Mean preoperative corneal thickness (pachymetry) was 399.5 +/- 127.1 microm. Mean preoperative spherical equivalent refraction was -1.13 +/- 3.33 D (range -9.38 to +10.00 D). No eye reached 20/15 BSCVA, and only 59% could see 20/30 BSCVA. At the final, 12-month examination, mean spherical equivalent refraction was -0.38 +/- 4.11 D (range -10.88 to +6.00 D). Eighty-eight percent of eyes reached 20/30 or better BSCVA, and 25% had 20/15 or better BSCVA. No eye developed corneal ectasia. CONCLUSIONS: At 1 year after surgery, custom phototherapeutic keratectomy (CPK) provided a reliable tool for treatment of highly aberrated eyes, and provided a surgical alternative to penetrating keratoplasty.

Reduction of spherical aberration with the nidek NAVEX customized ablation system.

PURPOSE: Spherical aberration is the most frequent optical aberration induced by refractive surgery, reducing visual acuity and causing halos. We present preliminary results of Custom Ablation Transition Zone (CATz), which we developed for Nidek's Final Fit software, part of the Nidek NAVEX customized ablation system. METHODS: We studied 55 eyes of 51 patients (31 males, 20 females) who underwent refractive surgery. Mean preoperative spherical equivalent refraction was -5.50 +/- 3.30 D (range -12.00 to +4.50 D). Mean age was 35 years (range 23 to 47 yr). All patients underwent complete preoperative ophthalmologic examination, including aberrometry and topography, then surgery with laser epithelial keratomileusis, and OPD-based refractive treatment with the Nidek EC-5000 excimer laser. The Nidek Final Fit software with the CATz feature was always used. Postoperatively, all patients repeated the ophthalmologic examination inclusive of aberrometry at day 30, 60, and 90. RESULTS: The 3-month follow-up rate was 21.8%. Mean postoperative spherical equivalent refraction was -0.33 +/- 0.91 D (range -0.75 to +0.75 D), with a mean sphere of -0.23 +/- 0.78 D (range -2.50 to +0.75 D) and a mean cylinder of -0.21 +/- 0.33 (range -1.00 to 0 D). At 3 months, 43% of eyes achieved 20/15 or better UCVA, and 43% achieved 20/20 or better UCVA; 63% achieved 20/15 or better BSCVA and 25% achieved 20/20 or better BSCVA. Postoperative spherical aberration was unchanged for a 3-mm pupil. CONCLUSION: Customized ablation with the Nidek NAVEX system provided excellent refractive results. The CATz algorithm of the Nidek Final Fit software appeared to prevent induction of spherical aberration.

The role of amino acids in corneal stromal healing: a method for evaluating cellular density and extracellular matrix distribution.

PURPOSE: To evaluate how amino acid supplementation influences the response of corneal stromal keratocytes and other components of the corneal stroma. METHODS: We compared two groups of patients undergoing cataract surgery. Each group included 20 eyes of 20 patients. Patients in Group 1 were treated with amino acids for 15 days before surgery, and patients in Group 2 did not receive amino acids (control). To evaluate differences and change in corneal stroma, we analyzed all of the operated corneas with confocal microscopy. The confocal images were then analyzed with a new method for measurement of corneal structure based on fractal dimension calculation. This led to a numerical value, D index (fractal surface dimension), an objective measurement of corneal stromal characteristics. This index is related to three factors: keratocyte density, stromal distribution pattern, and intercellular matrix structure. RESULTS: Patients in the preoperative amino acid group showed higher keratocyte density values than those in the control group. We observed differences in cell distribution patterns and intercellular matrix structures between groups. Amino acid-treated patients had a corneal stroma with a D index value 10% higher than control group patients. CONCLUSIONS: We hypothesized that preoperative oral supplements with amino acids may change the corneal stroma structure by increasing keratocyte density and modifying the intercellular matrix. A new method for the measurement of these changes was applied, which provides quantification of the stromal structure complexity with a single numerical value.

One-year results of butterfly laser epithelial keratomileusis.

PURPOSE: To evaluate the risks, complications, and refractive results at 1 year after modified laser epithelial keratomileusis (Butterfly LASEK). METHODS: In a non-randomized prospective study of 773 eyes (452 patients; mean age 34.3 +/- 16.5 years, mean preoperative spherical equivalent refraction -5.30 +/- 3.70 D; mean sphere -4.80 +/- 3.60 D; mean cylinder -1.00 +/- 1.40 D; range -22.50 to +5.50 D), we used a modified LASEK technique and evaluated complications and refractive results at 1 year. The technique is based on the formation of the epithelial flap utilizing alcohol (20% diluted solution applied on the epithelium for 5 to 30 seconds), paracentral abrasion, blunt dissection of the epithelium from the underlying plane; the epithelium is then separated by means of a specially designed retractor. Ablation was performed with a Nidek EC-5000 excimer laser, followed by smoothing and repositioning of the epithelial flap. RESULTS: After 1 year, we analyzed the results of 542 (70.1%) treated eyes with the following outcome: mean postoperative spherical equivalent refraction -0.20 +/- 1.40 D; mean sphere -0.10 +/- 1.30 D; mean cylinder -0.10 +/- 0.60 D; range -2.50 to +0.75 D. In 83.0% of treated eyes, achieved refraction was within +/-0.50 D of planned correction, with uncorrected visual acuity greater than or equal to 1.2 in 19.0% of treated eyes, greater than or equal to 1.0 in 56.0%, and greater than or equal to 0.8 in 19%. Concerning visual acuity, 0.3% of eyes lost 1 line, 49.8% of eyes had no change; 41.8% gained 1 line, 9.8% gained 2 lines, and 1.6% gained more than 2 lines. CONCLUSION: One-year results of this preliminary study showed that Butterfly LASEK was easy to perform, safe, and led to excellent long-term refractive results.