Management of irregular astigmatism following rotationally disoriented free cap after LASIK

PURPOSE: To illustrate the challenges associated with a misaligned free flap (cap) and to report the outcome of applying wavefront-guided customized photorefractive keratectomy (PRK) followed by conventional PRK ablation to correct residual refractive error and aberrations after LASIK free cap complications. METHODS: The clinical course and surgical interventions of two patients with free cap complications from LASIK surgery were reviewed. The first patient underwent a total of six interventions after the initial LASIK procedure, and the second patient underwent a total of five interventions. Interventions included cap lift, cap rotation, custom PRK, and conventional PRK enhancement with prophylactic topical mitomycin C (MMC). RESULTS: Customized PRK treatment and subsequent enhancements with prophylactic topical MMC led to the recovery of best spectacle-corrected visual acuity (BSCVA), neutralization of higher and lower order aberrations, and astigmatic neutrality. Symptoms related to higher order aberrations resolved in both patients. CONCLUSIONS: Wavefront-guided custom PRK for higher order aberrations followed by conventional PRK enhancement for residual lower order aberrations, both with topical MMC application, represents an efficacious strategy for treating patients with loss of BSCVA and visual symptoms due to LASIK free cap complications.     

Wavefront customized ablations with the WASCA Asclepion workstation

PURPOSE: WASCA (Wavefront Aberration Supported Cornea Ablation) is a method for wavefront-guided ablation. This new method records all existing eye aberrations with the Asclepion Wavefront Aberrometer and calculates the customized pattern for laser correction. We measured the low and high order aberrations of eyes before and after PRK and LASIK, as well as before and after flap creation. METHODS: The Asclepion Shack-Hartmann aberrometer was used to measure wavefront aberrations. Preoperative and postoperative measurements were made following both PRK and LASIK performed with conventional software, modified Aberration-free Profile (AFA) software, and specially designed WASCA software. Surgery was performed with the Meditec MEL-70 G-scan excimer laser. Additionally, measurements were made before and after flap creation only (10 eyes). RESULTS: There was a significant difference between preoperative and 1-month postoperative high order aberrations, with notable increases following conventional PRK and LASIK and less increase following modified AFA PRK and LASIK. Flap creation only changed the higher order aberrations slightly, and caused a shift toward hyperopia. In the eyes that received WASCA correction with PRK or LASIK, at 3 months postoperative the high order aberrations averaged an increase of 1.3 times for PRK and 1.8 times for LASIK. Both the AFA and WASCA treatments demonstrated improved outcomes in comparison to conventional PRK and LASIK. CONCLUSION: Wavefront mapping of the eye and wavefront-guided ablation with the Asclepion Aberrometer can be used for optimizing the results and fine-tuning visual performance after laser vision correction. WASCA PRK appeared to result in better outcomes than WASCA LASIK.     

Photorefractive keratectomy with mitomycin C for the management of a LASIK flap complication following a penetrating keratoplasty

OBJECTIVE: To evaluate the safety and efficacy of photorefractive keratectomy (PRK) with mitomycin C (MMC) following a buttonhole secondary to attempted laser in situ keratomileusis (LASIK) in an eye that had undergone a prior penetrating keratoplasty (PKP). METHODS: Case report and review of the literature. A 26-year-old man underwent PRK with MMC following a buttonhole flap complication after LASIK in an eye that had undergone a PKP for keratoconus. RESULTS: Three months following the procedure, the patient demonstrated a clear cornea and a best-corrected visual acuity of 20/20. CONCLUSION: To our knowledge, this is the first case report of buttonhole during LASIK following a PKP and the use of PRK to treat a LASIK flap complication following a successful PKP. In addition, this is the first case report of prophylactic use of MMC to prevent corneal haze with PRK following PKP. A buttonhole is a rare complication following LASIK for residual refractive error following PKP, which can be successfully managed with PRK and prophylactic MMC.     

Wavefront-guided laser in situ keratomileusis: early results in three eyes

PURPOSE: Wavefront optical aberrations induced by refractive corneal surgery correction of myopia are probably the reason for deterioration of visual performance in some eyes after surgery. Customized photoablation of the cornea to correct both the sphero-cylindrical refractive error as well as individual optical aberrations may improve postoperative visual acuity and visual performance. METHODS: In 3 eyes of 3 patients the wavefront deviations were measured by means of an aberrometer of the Tscherning-type. Based on these measurements an ablation pattern was determined and applied during a LASIK procedure using a Wavelight Allegretto scanning spot excimer laser with a spot size of 1 mm and a laser repetition rate of 200 Hz. The 3 eyes are part of a prospective study on wavefront-guided LASIK started in July 1999. RESULTS: At 1 month after LASIK, all 3 eyes had gained up to 2 lines of best spectacle-corrected visual acuity. Best spectacle-corrected visual acuity improved to 20/10 in all 3 eyes, uncorrected visual acuity was 20/10 in two eyes, and 20/12.5 in 1 eye 1 month postoperatively. The wavefront deviations were reduced by 27% on average. At 3 months, best spectacle-corrected visual acuity was 20/10 in 2 eyes and 20/12.5 in 1 eye. CONCLUSION: Wavefront-guided LASIK is a feasible approach in refractive corneal surgery. Optimized ablation patterns may further improve the visual results.     

Mitomycin-C assisted photorefractive keratectomy in the treatment of buttonholed laser in situ keratomileusis flaps associated with epithelial ingrowth

The prophylactic intraoperative use of mitomycin-C (MMC) to prevent haze and scarring after excimer laser surface ablation (phototherapeutic/photorefractive keratectomy [PTK/PRK]) in an eye with a previous laser in situ keratomileusis (LASIK) flap buttonhole with epithelial ingrowth is described. A well-centered buttonhole measuring 2.0 mm in diameter was cut within a thin LASIK flap in an amblyopic eye. Over the next 8 weeks, corneal haze and progressive epithelial ingrowth formed centrally. An early transepithelial PTK/PRK approach was chosen to manage the buttonhole together with the epithelial ingrowth and to treat ametropia before the onset of scarring. The approach included epithelial removal with PTK, application of MMC 0.02% for 1 minute, irrigation, a short waiting period to allow for diffusion, PRK correction of -4.0 diopters without nomogram adjustment, and bandage contact lens. A regimen of prednisolone acetate 1% and ofloxacin 0.03% 5 times a day for 1 week (steroid tapered) was prescribed. Epithelial ingrowth was removed successfully. Minimal haze formation was visible 2 weeks after the retreatment but did not reduce best spectacle-corrected visual acuity (BSCVA) and resolved within the next few weeks. After 6 weeks, uncorrected visual acuity was equal to BSCVA preoperatively (20/50). There was no evidence of recurrent epithelial ingrowth or central scarring after 24 months. Transepithelial PTK/PRK was effective in managing central epithelial ingrowth in a buttonholed LASIK flap. Prophylactic intraoperative use of MMC may reduce haze formation and corneal scarring in early treatments and may also prevent recurrent epithelial ingrowth. This approach may offer faster visual recovery and no risk for a repeated buttonhole creation compared with the widespread recutting a new flap after a couple of months. The optimal application time and concentration of MMC need to be established.     

Lower intraoperative flap complication rate with the Hansatome microkeratome compared to the Automated Corneal Shaper

PURPOSE: The purpose of this study was to retrospectively compare the incidence of intraoperative flap complications, such as partial flaps, donut-shaped flaps, central corneal cuts, and complete caps with the Hansatome and Automated Corneal Shaper (ACS) microkeratomes. METHODS: All laser in situ keratomileusis (LASIK) procedures performed by a single surgeon with the Hansatome or Automated Corneal Shaper in which intraocular pressure was verified with a pneumotonometer were reviewed. RESULTS: A total of 90 eyes had LASIK with the ACS microkeratome. Six of the ACS eyes (6.7%) had intraoperative flap complications (4 partial flaps, 1 donut-shaped flap, 0 central corneal cuts, 1 complete cap). Partial flaps and donut-shaped flaps were replaced without laser application and the procedure repeated 2 to 3 months later. Two of these eyes lost 2 lines and one lost 1 line of spectacle-corrected visual acuity at 6 months after repeat LASIK. The eye with the donut-shaped flap was treated with transepithelial photorefractive keratectomy (PRK) and had no change in spectacle-corrected visual acuity at 6 months after PRK. The eye with the complete cap had no change in spectacle-corrected visual acuity after laser ablation. Five hundred ninety-eight (598) eyes had LASIK with the Hansatome microkeratome. Two of the Hansatome eyes (0.3%) had a flap complication (1 partial flap and 1 donut-shaped flap). The first eye retained spectacle-corrected visual acuity at 6 months after repeat LASIK. The second eye had transepithelial PRK to eliminate the donut shaped flap with no loss of spectacle-corrected visual acuity at 6 months after surgery. The difference in flap complications between the two procedures was statistically significant (P < .01). There were no flap displacements following surgery in either group. CONCLUSION: Intraoperative flap complications are less likely to occur with the Hansatome microkeratome than with the ACS microkeratome.     

Prophylactic use of mitomycin-C in the management of a buttonholed LASIK flap

We report a case in which prophylactic mitomycin-C (MMC) was used to prevent haze and scarring after photorefractive keratectomy (PRK) in an eye with a previous laser in situ keratomileusis flap buttonhole. During the patient's primary procedure, a 3.5 mm central buttonhole was created during the microkeratome pass. The flap was repositioned without laser application. Follow-up examinations revealed a moderate central buttonhole scar. Twelve months later, the patient had PRK with adjunctive MMC 0.02% application in the eye. At the 1-year examination, the uncorrected visual acuity was 20/20 and the cornea was clear with no evidence of scarring or haze.     

Prospective randomized comparison of wavefront-guided and conventional photorefractive keratectomy for myopia with the meditec MEL 70 laser

PURPOSE: To study refractive results and aberrometric changes in myopic patients treated with wavefront-guided photorefractive keratectomy (PRK) in comparison with standard PRK. METHODS: Sixty eyes of 60 patients with myopic astigmatism were randomly divided into two groups. Group 1 included 30 eyes (mean spherical equivalent refraction -4.39 +/- 1.31 D; range -2.50 to -6.50 D) treated with wavefront-guided PRK using the WASCA workstation and the Asclepion Meditec flying spot MEL 70 excimer laser. Group 2 had 30 eyes (mean spherical equivalent refraction -4.33 +/- 1.22 D; range -2.50 to -6.50 D) that underwent conventional PRK using the same laser, and served as the control group. Wavefront analysis of high order aberrations was performed before and 6 months after surgery. RESULTS: Postoperatively, wavefront error increased in both groups (5.0-mm wavefront aperture diameter). Six months after surgery, the eyes that received the WASCA ablation had a smaller increase in root-mean-square (RMS; 70% of increment) compared to the conventional PRK group (139% of increment) (P<.001). In the standard PRK group, all aberrations notably increased; in the wavefront-guided PRK group there was a smaller increase of trefoil and spherical aberrations (P<.001) and a decrease of coma aberrations (P<.001). The smaller increase of wavefront error in the wavefront-guided PRK group compared to the standard PRK group was more evident when preoperative RMS values were higher than 0.4 microm (P<.01). The visual parameters (spherical equivalent refraction, uncorrected and best spectacle-corrected visual acuity) did not show significant differences between the two groups. CONCLUSION: Wavefront-guided PRK induced a smaller increase of postoperative wavefront-error compared to conventional PRK, particularly in patients with higher preoperative higher order aberrations.     

Immediate transepithelial photorefractive keratectomy for treatment of laser in situ keratomileusis flap complications

PURPOSE: To study the role of photorefractive keratectomy (PRK) in the management of laser in situ keratomileusis (LASIK) flap complications. METHODS: A retrospective analysis was performed of seven patients (14 eyes) who had bilateral, simultaneous LASIK (single surgeon [TGA], Summit Apex Plus laser, Hansatome microkeratome in six patients [12 eyes], Automated Corneal Shaper keratome in one patient [two eyes]). One eye of each patient received PRK for a flap complication. The seven patients (four women, three men) had a mean age of 39.2 years (range, 22 to 64 yr). The uncomplicated LASIK eyes had moderate to high myopia (-2.25 to -8.75 D) and the eyes with LASIK flap complications had mild to moderate myopia (-1.50 to -5.75 D). Immediate transepithelial PRK was performed in all eyes after repositioning the defective flap. RESULTS: All seven patients had excellent visual outcome at 6 months follow-up; one patient required an enhancement (astigmatic keratotomy). Six of the seven LASIK eyes had best spectacle-corrected visual acuity of 20/20 or better and one LASIK eye had 20/25. In the transepithelial PRK eyes, six of the seven eyes had best spectacle-corrected visual acuity of 20/20 or better and one eye had 20/30. CONCLUSIONS: Immediate transepithelial PRK treatment of irregular and incomplete LASIK flaps at the time of surgery is an excellent therapeutic option to delayed surgical treatment.     

Repositioning of free cap four days after LASIK

PURPOSE: To report management and outcome of late repositioning of flap dislodgement after LASIK. METHODS: A 27-year-old man underwent LASIK in the right eye for correction of myopia, which was complicated by free cap. The flap was repositioned, but dislodged 2 days later. The dislodged flap was stored in balanced salt solution for 48 hours and repositioned 4 days after initial surgery. RESULTS: Postoperatively, the flap remained apposed, but diffuse lamellar keratitis and epithelial ingrowth developed, which was managed with topical steroids and topical mitomycin C. Stromal haze gradually decreased by 16 months postoperatively, resulting in best spectacle-corrected visual acuity of 20/20. CONCLUSIONS: Flap dislodgement > 48 hours postoperatively can be repositioned with good visual outcome. The flap should be preserved in the event of such complication.     

Alcon LADARWave customcornea retreatments

PURPOSE: To present our experience performing wavefront-guided ablations for the treatment of residual refractive error following previous refractive surgery. METHODS: Four different cases are presented-1) primary wavefront-guided LASIK; 2) wavefront-guided lift-flap LASIK retreatment; 3) wavefront-guided photorefractive keratectomy (PRK) retreatment; and 4) wavefront-guided PRK over radial keratotomy retreatment. All procedures were performed with the Alcon CustomCornea laser platform. Uncorrected visual acuity (UCVA), best spectacle-corrected visual acuity (BSCVA), manifest refraction, and wavefront analysis (6.5-mm pupil) were performed preoperatively and 3 months after CustomCornea retreatment. The Alcon LADARWave device was used for wavefront measurements. RESULTS: Total lower order and higher order aberrations were decreased following wavefront-guided retreatment, resulting in improved quality of vision. The maximum target offset (+ 0.75 diopters) can be used to prevent an overcorrection of defocus (myopia) when treating a significant amount of spherical aberration. CONCLUSIONS: Wavefront-guided ablation was an effective treatment for residual lower and higher order aberrations following previous refractive surgery. Custom ablation treatment algorithms need to be developed specifically for retreatment procedures.     

Photorefractive keratectomy for treatment of flap complications in laser in situ keratomileusis

PURPOSE: To present the results of photorefractive keratectomy (PRK) for treatment of laser in situ keratomileusis (LASIK) flap complications. METHODS: Compilation of case reports through solicitation on Kera-net, an Internet surgery discussion site. RESULTS: PRK was performed on 13 patients from 2 weeks to 6 months after LASIK flap complications. The technique used for the PRK varied. Epithelial removal was performed using no-touch phototherapeutic keratectomy (PTK) in six of the 13 patients and manual debridement in the other seven patients. A dilute solution of 20% ethanol was used to facilitate manual debridement in five of the seven patients. In two of these five patients, the epithelium was replaced as in laser-assisted subepithelial keratomileusis (LASEK). A solution of 0.02% mitomycin C was used after laser ablation to prevent haze formation in three patients. After an average 7 months of follow-up, uncorrected visual acuity was 20/20 in six patients, 20/25 in four patients, and 20/30 in two patients. The visual acuity in one patient was 20/80, purposely left undercorrected for monovision. Best spectacle-corrected visual acuity was 20/20 in 10 of 13 patients. Three patients were 20/25, losing one line of best spectacle-corrected visual acuity. On slit-lamp examination, at last follow-up appointment, stromal haze was graded from trace to none in all patients. CONCLUSIONS: Photorefractive keratectomy is a safe and effective technique for treatment of patients with LASIK flap complications.     

Alcon CustomCornea wavefront-guided retreatments after laser in situ keratomileusis

PURPOSE: To evaluate the outcome of wavefront-guided ablations for the correction of residual myopia and astigmatism after standard laser in situ keratomileusis (LASIK). METHODS: Twenty nine eyes of 26 patients who underwent wavefront-guided LASIK retreatment with Alcon CustomCornea (Alcon Laboratories Inc, Fort Worth, Tex) were evaluated. Complete ophthalmologic examination, corneal topography, and wavefront measurements were performed. Uncorrected visual acuity (UCVA), best spectacle-corrected visual acuity (BSCVA), manifest refraction, and wavefront analysis were evaluated preoperatively, 1 week, 3 months, and 6 months after surgery. Wavefront measurements were assessed using the LADARWave device. Statistical analysis was performed using the McNemar test and percentages of success. RESULTS: One week postoperatively, UCVA was > or =20/40 in 100% of eyes (> or =20/20 in 31%) and BSCVA was > or =20/40 in 100% (> or =20/20 in 73%). Wavefront analysis showed a decrease in total aberrations, high order aberrations, defocus, coma, spherical aberration, and other terms of higher order aberrations at 1-week follow-up. Three months postoperatively, UCVA was > or =20/40 in 100% of eyes (> or =20/20 in 38%) and BSCVA was > or =20/40 in 100% (> or =20/20 in 81%). Six months postoperatively, UCVA was > or =20/40 in 100% of eyes (> or =20/20 in 60%) and BSCVA was > or =20/40 in 100% (> or =20/20 in 90%). Wavefront analysis showed decrease in total aberration, high order aberration, defocus, coma, and spherical aberration. CONCLUSION: Wavefront-guided LASIK retreatment in post-LASIK eyes represents a good option for laser vision correction. All eyes showed reduction in pre-existing total aberrations. Some high order aberration components decreased in this initial series. Further follow-up is necessary to assess the initial predictability of wavefront-guided LASIK upgrade.     

Photorefractive keratectomy with mitomycin C versus LASIK in custom surgeries for myopia: a bilateral prospective randomized clinical trial

PURPOSE: To compare photorefractive keratectomy (PRK) with prophylactic use of mitomycin C (MMC) and LASIK in custom surgeries for myopic astigmatism. METHODS: Eighty-eight eyes of 44 patients with a minimum estimated ablation depth of 50 microm were randomized to receive PRK with MMC 0.002% for 1 minute in one eye and LASIK in the fellow eye. Uncorrected visual acuity (UCVA), best spectacle-corrected visual acuity (BSCVA), cycloplegic refraction, slit-lamp microscopy, contrast sensitivity, specular microscopy, aberrometry, and a subjective questionnaire were evaluated. Forty-two patients completed 6-month follow-up. RESULTS: Mean spherical equivalent refraction error before surgery and mean ablation depth were -3.99+/-1.20 diopters (D) and 73.09+/-14.55 microm in LASIK eyes, and -3.85+/-1.12 D and 70.7+/-14.07 microm in PRK with MMC eyes, respectively. Uncorrected visual acuity was significantly better in PRK with MMC eyes 3 months (P=.04) and 6 months (P=.01) after surgery. Best spectacle-corrected visual acuity and spherical equivalent refraction did not differ significantly in the groups during follow-up (P>.05). Significant haze was not observed in any PRK with MMC eye. Mean higher order aberration was lower in PRK with MMC eyes postoperatively compared with LASIK eyes (P=.01). Better contrast sensitivity was observed in PRK with MMC eyes than LASIK eyes (P<.05). The endothelial cell count did not differ significantly between groups (P=.65). In terms of visual satisfaction, PRK with MMC eyes were better rated. CONCLUSIONS: Photorefractive keratectomy with MMC appears to be more effective than LASIK in custom surgery for moderate myopia. During 6-month follow-up, no toxic effects of MMC were evident. Long-term follow-up is necessary to attest its safety.     

LASIK手术偏心切削病例的分析

目的 分析因传统准分子激光原位角膜磨镶术（LASIK）和波前像差引导的LASIK（波前引导LASIK）偏心切削引发视觉质量下降的病例中,其高阶像差分布特征和偏心切削程度的评价.方法 回顾性病例对照研究.初次LASIK术后（包括传统LASIK和波前引导LASIK）出现重影和星芒等视觉症状的患者40例（48眼）,术后复诊3个月以上[复诊期限：波前引导组平均为9个月（4至26个月）,传统组平均为24个月（5个月至6年）],屈光度稳定在±1.00 D以内者,除外过矫、欠矫和眼表及眼内疾患导致的视力下降,行WaveScan（3.62版）波前像差仪检查.本研究选取了这部分患者中初次LASIK术后主导像差为彗差（垂直彗差或水平彗差）的26例（28眼）,分析检测所得高阶像差结果,并测定术中偏心的切削中心相对瞳孔中心在水平方向（X轴）、垂直方向（Y轴）和矢量的偏移.将波前像差引导LASIK组的术前与术后结果采用配对t检验或者配对秩和检验进行比较;波前像差引导LASIK组术后与传统LASIK组术后结果采用独立样本t检验或者独立样本秩和检验进行比较.结果 波前引导组的总高阶像差均方根值（RMS）由（0.425±0.192）μm增加至术后的（1.262±0.590）μm,增加了1.96倍.总彗差RMS值由（0.190±0.114）μm增加至术后的（0.686±0.315）μm,增加了 2.61倍.水平彗差RMS值由（0.118±0.061）μm增加至术后的（0.257±0.237）μm,增加了1.17倍;垂直彗差RMS值由（0.130±0.122）μm增加至术后的（0.587±0.329）μm,增加了3.51倍.初次LASIK术后的水平彗差明显小于垂直彗差（Z=-2.803,P=0.004）.传统组的总高阶像差、总慧差与波前引导组比较,差异无统计学意义,但总慧差占总高阶像差的比例,两组差异有统计学意义（t=-1.548,P=0.007）.偏心切削量水平方向（X轴）位移右眼为（0.65±0.38）mm,左眼为（0.90±0.35）mm;垂直方向（Y轴）位移右眼为（0.80±0.30）mm,左眼为（0.53±0.34）mm;矢量位移右眼为（1.11±0.25）mm,左眼为（1.13±0.22）mm.全部28眼矢量位移均＞0.5 mm,71%的患眼切削中心偏移瞳孔中心的距离＞1.0 mm,矢量位移程度是LASIK术后无视觉症状人群的2.02倍.右眼在垂直方向（Y轴）的位移大于左眼（t=2.157,P=0.040）结论由于偏心切削引发的LASIK术后视觉质量下降病例中,高阶像差和总彗差明显增加,垂直彗差增加大于水平彗差;其偏心切削的程度属于中度和重度偏移.因此,偏心切削是LASIK术后视觉质量下降的主要原因之一.     

Changes in higher order aberrations after wavefront-guided PRK for correction of low to moderate myopia and myopic astigmatism: two-year follow-up

PURPOSE: To assess efficacy, safety, and changes in higher order aberrations after wavefront-guided photorefractive keratectomy (PRK) in comparison with conventional PRK for low to moderate myopia with myopic astigmatism using a WASCA Workstation with the MEL 70 G-Scan excimer laser. METHODS: A total of 126 myopic or myopic-astigmatic eyes of 112 patients were included in this retrospective study. Patients were divided into two groups: Group 1, the study group; and Group 2, the control group. Group 1 consisted of 78 eyes treated with wavefront-guided PRK. Group 2 consisted of 48 eyes treated with spherocylindrical conventional PRK. RESULTS: Two years postoperatively, in Group 1, 5% of eyes achieved an uncorrected visual acuity (UCVA) of 0.05; 69% achieved a UCVA of 0.00; 18% of eyes experienced enhanced visual acuity of -0.18 and 8% of -0.30. In Group 2, 8% of eyes achieved a UCVA of 0.1; 25% achieved a UCVA of 0.05; and 67% achieved a UCVA of 0.00 according to logMAR calculation method. Total higher-order root-mean square increased by a factor 1.18 for Group 1 and 1.6 for Group 2. There was a significant increase of coma by a factor 1.74 in Group 2 and spherical aberration by a factor 2.09 in Group 1 and 3.56 in Group 2. CONCLUSIONS: The data support the safety and effectiveness of the wavefront-guided PRK using a WASCA Workstation for correction of low to moderate refractive errors. This method reduced the number of higher order aberrations induced by excimer laser surgery and improved uncorrected and spectacle-corrected visual acuity when compared to conventional PRK.     

Wavefront-guided excimer laser ablation using photorefractive keratectomy and sub-Bowman's keratomileusis: a contralateral eye study

PURPOSE: To explain the basic science and clinical evidence that has led to the development of a new technique in corneal refractive surgery--sub-Bowman's keratomileusis (SBK). METHODS: A comprehensive review of the literature and report of a contralateral eye study of 50 patients (100 eyes) enrolled at 2 sites (25 patients per site) and randomized according to the dominant eye was conducted. All eyes underwent a wavefront-guided refractive correction using the Alcon LADARVision4000 System. In one eye, an 8.5-mm, ETOH-assisted photorefractive keratectomy (PRK) was performed. In the second eye, an 8.5-mm, 100-microm flap was attempted using a 60 kHz IntraLase FS femtosecond laser. Pre- and postoperative tests included best spectacle-corrected visual acuity, uncorrected visual acuity, corneal topography, wavefront aberrometry, retinal image quality, contrast sensitivity, and biomechanical response of the cornea. Patients completed subjective questionnaires at each follow-up. RESULTS: Clinical results demonstrate that SBK provides quicker visual recovery, although the data suggest that the 3- and 6-months results are similar in terms of visual outcomes. Reichert Ocular Response Analyzer results demonstrate that its impact on the cornea is similar to PRK. CONCLUSIONS: This study indicates that SBK provides the visual recovery of a LASIK procedure with the Optical Response Analyzer results similar to PRK.     

Combined Artemis very high-frequency digital ultrasound-assisted transepithelial phototherapeutic keratectomy and wavefront-guided treatment following multiple corneal refractive procedures

We present a patient with severe visual symptoms following multiple corneal refractive procedures including automated lamellar keratoplasty, arcuate keratotomy, laser in situ keratomileusis (LASIK), LASIK enhancement by cutting another flap, followed by a further LASIK enhancement by flap lifting. Topography was irregularly irregular, and the best spectacle-corrected visual acuity (BSCVA) was 20/25. Artemis very high-frequency digital ultrasound (US) analysis of the anatomical irregularities of the epithelium and stroma was used in conjunction with the topography to determine the cause of the visual symptoms. Very high-frequency digital US-assisted transepithelial phototherapeutic keratectomy together with a wavefront-guided treatment was used to reduce the stromal surface irregularities and the higher-order aberrations (HOAs), respectively. The treatment successfully regularized the stromal surface, dramatically reduced the HOAs, improved the contrast sensitivity to the high normal range, and improved the BSCVA to 20/20.     

Wavefront-guided treatment of abnormal eyes using the LADARVision platform

PURPOSE: To evaluate the clinical results of Alcon LADARVision4000 wavefront-guided customized treatment of eyes with myopia and/or astigmatism, and clinically significant visual symptoms related to the presence of higher order aberrations. METHODS: Seven consecutive abnormal eyes from seven patients underwent wavefront-guided CustomCornea (1 PRK, 6 enhancements after previous LASIK) to correct low and higher order aberrations, using the Alcon LADARVision4000 platform. Eyes were examined at 1 to 3 months after treatment; the longest follow-up examination was used for analysis. Uncorrected and best spectacle-corrected visual acuity, manifest refractive spherical equivalent error, and subjective visual symptoms were measured, as well as wavefront measurement of higher order aberrations. RESULTS: All seven eyes had an improvement in UCVA. One eye gained 2 lines of BSCVA, four eyes gained 1 line, and no eye lost any lines. Manifest refractive spherical equivalent error was slightly hyperopic in all eyes (+0.12 to +1.50 D). All eyes showed a reduction in pre-existing higher order aberrations, ranging between 1% and 48%. Spherical aberration was reduced most (mean 38% reduction), coma was reduced by a mean 14%, and all other terms were reduced by a mean 17% compared to preoperative values. Subjectively, all patients noticed a reduction in their pre-existing visual symptoms and reported visual performance comparable to their fellow asymptomatic eye. Overall, the treatment was considered very satisfactory by patients in terms of visual quality gain. CONCLUSION: Wavefront-guided custom ablation with Alcon's LADARVision4000 was effective in reducing higher order aberrations and related visual symptoms in this preliminary small series. Longer follow-up on more eyes is necessary to assess the accuracy of the algorithm in the correction of defocus, which resulted in a slight overcorrection in this study.     

Aberration-sensing and wavefront-guided laser in situ keratomileusis: management of decentered ablation

PURPOSE: To clarify the feasibility of aberration-sensing and wavefront-guided laser in situ keratomileusis (LASIK) to manage grossly decentered ablation and to discuss the limitations of the technology. METHODS: Three patients with previous decentrations of the ablation zone between 1.5 to 2.0 mm were scheduled for wavefront-guided LASIK. All patients reported monocular diplopia and halos. Wavefront aberrations were measured with a Tscherning-type aberrometer. Laser ablation was done with a WaveLight Allegretto in a one-step procedure with ablation profiles calculated only from the individual wavefront map. Decentrations were determined from corneal topography. RESULTS: Three months after surgery, patient WM and patient SU had gained uncorrected and best spectacle-corrected visual acuity. The root mean square-wavefront error decreased up to 61% and 33%, respectively, for total and higher order aberrations (Zernike modes of 3rd order and higher). There was significant enlargement of the optical zone determined by corneal topography, and both patients no longer reported diplopia and halos at 3 months postoperatively. The optical aberration of the third patient (RE), after a 5.00-D overcorrection with a 2-mm decentration, was too high for aberration-sensing; retinal images obtained from the wavefront device were too smeared and not of sufficient contrast. In addition, this patient had a residual corneal thickness of 416 microm and thus wavefront-guided LASIK was not done. CONCLUSIONS: Wavefront-guided LASIK offers a new way of managing grossly decentered laser ablations. Unfortunately, there are still patients who have aberrations too large for wavefront sensing or with other clinical limitations such as a residual corneal thickness too thin for further treatment.