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Comparison of 9.0 and 9.2 mm Flap Diameter Options of Femtosecond Laser In-Situ Keratomileusis for Hypermetropia and Hypermetropic Astigmatism. J Ophthalmol 2019; 2019:5907645. [PMID: 31781379 PMCID: PMC6875365 DOI: 10.1155/2019/5907645] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2019] [Accepted: 10/08/2019] [Indexed: 11/17/2022] Open
Abstract
Aim To compare the postoperative one-year outcomes of asphericity (Q) and high order aberration (HOA) values of 9.0 and 9.2 mm diameter flap groups in hypermetropia and hypermetropic astigmatism subjects who underwent femtosecond laser in-situ keratomileusis (LASIK). Materials and Methods The study included 68 eyes of 34 patients. A femtosecond laser platform (Allegrato Wave, Wavelight AG, Erlangen, Germany) was used for flap cutting. Corneal stroma was ablated using Wavelight EX500 with wavefront-optimized profile (WaveLight GmbH, Erlangen, Germany). 9.0 mm flap diameter was randomly chosen for one eye, and 9.2 mm flap diameter was chosen for the fellow eye. Two eyes of the patients who used two different flap diameters were enrolled into two different groups. Corneal stroma was ablated using Wavelight EX500 with wavefront-optimized profile (WaveLight GmbH, Erlangen, Germany). Postoperative one-year outcomes of Q and HOA values of 9.0 and 9.2 mm diameter flap groups were compared statistically. Results The preoperative manifest refraction spherical equivalents of the 9.0 and 9.2 mm diameter flap groups were 1.86 ± 1.81 D and 1.69 ± 1.99 D (p=0.754). No intraoperative or postoperative complications were observed. At postoperative one-year, Q values were 0.98 ± 0.13 D and 0.91 ± 0.15 D (p=0.029). HOAs including horizontal and vertical coma, horizontal and vertical trefoil, spherical aberration, and second order vertical coma were not significantly different (p > 0.05 for all). Total HOA values were 1.62 ± 0.14 and 1.40 ± 0.16, in the 9.0 and 9.2 mm diameter flap groups, respectively (p < 0.001). Conclusion Both the 9.0 and 9.2 mm diameter flap options in femtosecond LASIK are equally safe and effective. Many of the HOA values are similar in both options, and better results were provided in terms of total HOA and Q values with the 9.2 mm diameter flap option. This study was registered with trial registration number 118-011.
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Astigmatic outcomes in myopic wavefront-guided laser in situ keratomileusis versus wavefront-guided photorefractive keratectomy using vector analysis. J Cataract Refract Surg 2018; 44:1350-1354. [DOI: 10.1016/j.jcrs.2018.07.022] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2017] [Revised: 06/23/2018] [Accepted: 07/04/2018] [Indexed: 11/21/2022]
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Shao D, Zhu X, Sun W, Cheng P, Chen W, Wang H. Effects of femtosecond laser-assisted cataract surgery on dry eye. Exp Ther Med 2018; 16:5073-5078. [PMID: 30542462 PMCID: PMC6257160 DOI: 10.3892/etm.2018.6862] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2018] [Accepted: 10/09/2018] [Indexed: 12/13/2022] Open
Abstract
The aim of this study was to investigate the effect of femtosecond laser-assisted cataract surgery (FLACS) on tear film and ocular surface function. Patients with age-related cataract who underwent phacoemulsification (phaco) in Air Force Aviation Medicine Research Institute Affiliation Hospital from January 2016 to December 2016 were randomly divided into two groups. Patients in experimental group (n=123, 150 eyes) received FLACS, while patients in phaco group (n=110, 150 eyes) underwent conventional coaxial micro-incision phaco and were implanted with foldable intraocular lens (IOL). Our results showed that there were no statistically significant differences in general conditions between the two groups. Ocular surface disease index (OSDI) and corneal fluorescein staining (CFS) scores of patients in both groups after operation were significantly increased compared with those before operation, but breakup time (BUT) and Schirmer's I test scores decreased significantly at 1 week after operation compared with those before operation and basically returned to preoperative baseline levels at 3 months after operation. CFS scores and OSDI in the FLACS group at 1 day and 1 week after operation were increased more significantly than those in the phaco group, but there were no statistically significant differences at 3 months after operation. The above results showed that the effect on ocular surface function in the FLACS group after operation was greater than that in the phaco group, and the dry eye symptoms in the FLACS group were more obvious after operation. Both FLACS and conventional phaco have certain effects on the ocular surface function of patients, and there are statistically significant differences only in the early stage. FLACS has greater effects on CFS and dry eye symptoms.
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Affiliation(s)
- Dewang Shao
- Department of Ophthalmology, Air Force Aviation Medicine Research Institute Affiliation Hospital, Beijing 100089, P.R. China
| | - Xiaoquan Zhu
- Department of Ophthalmology, Air Force Aviation Medicine Research Institute Affiliation Hospital, Beijing 100089, P.R. China
| | - Wei Sun
- Department of Ophthalmology, Air Force Aviation Medicine Research Institute Affiliation Hospital, Beijing 100089, P.R. China
| | - Peng Cheng
- Department of Ophthalmology, Air Force Aviation Medicine Research Institute Affiliation Hospital, Beijing 100089, P.R. China
| | - Wei Chen
- Department of Ophthalmology, Air Force General Hospital, Beijing 100089, P.R. China
| | - Hua Wang
- Department of Ophthalmology, Air Force General Hospital, Beijing 100089, P.R. China
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Djodeyre MR, Beltran J, Ortega-Usobiaga J, Gonzalez-Lopez F, Ruiz-Rizaldos AI, Baviera J. Long-term evaluation of eyes with central corneal thickness <400 μm following laser in situ keratomileusis. Clin Ophthalmol 2016; 10:535-40. [PMID: 27099459 PMCID: PMC4820216 DOI: 10.2147/opth.s100690] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
Abstract
Purpose To study long-term refractive and visual outcomes of laser in situ keratomileusis (LASIK) in eyes with a postoperative thin central cornea. Methods In this retrospective observational case series, we studied 282 myopic eyes with a normal preoperative topographic pattern and postoperative thin corneas (<400 μm) that had at least 3 years of follow-up after LASIK in three private clinics. The main outcome measures were safety, efficacy, predictability, percent tissue altered, and complications. Results The mean postoperative central corneal thickness was 392.05 μm (range: 363.00–399.00 μm). After a mean follow-up of 6.89±2.35 years (standard deviation), the safety index was 1.17, the efficacy index was 0.94, and predictability (±1.00 diopter [D]) was 73.49. The mean residual stromal bed thickness was 317.34±13.75 μm (range: 275–356 μm), the mean flap thickness was 74.76±13.57 μm (range: 55–124 μm), and the mean percent tissue altered was 37.12%±3.62% (range: 27.25%–49.26%). No major complications were recorded. Conclusion LASIK with a resultant central cornea thickness <400 μm seems to be effective, safe, and predictable provided that preoperative topography is normal and the residual stromal bed thickness is >275 μm.
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Affiliation(s)
| | - Jaime Beltran
- Department of Refractive Surgery, Clinica Baviera, Valencia, Spain
| | | | | | | | - Julio Baviera
- Department of Refractive Surgery, Clinica Baviera, Valencia, Spain
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Liu HH, Hu Y, Cui HP. Femtosecond laser in refractive and cataract surgeries. Int J Ophthalmol 2015; 8:419-26. [PMID: 25938066 DOI: 10.3980/j.issn.2222-3959.2015.02.36] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2014] [Accepted: 09/15/2014] [Indexed: 11/02/2022] Open
Abstract
In the past few years, 9 unique laser platforms have been brought to the market. As femtosecond (FS) laser-assisted ophthalmic surgery potentially improves patient safety and visual outcomes, this new technology indeed provides ophthalmologists a reliable new option. But this new technology also poses a range of new clinical and financial challenges for surgeons. We provide an overview of the evolution of FS laser technology for use in refractive and cataract surgeries. This review describes the available laser platforms and mainly focuses on discussing the development of ophthalmic surgery technologies.
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Affiliation(s)
- Han-Han Liu
- Department of Ophthalmology, Shanghai East Hospital Affiliated to Tongji University, Shanghai 200120, China
| | - Ying Hu
- Department of Ophthalmology, Shanghai East Hospital Affiliated to Tongji University, Shanghai 200120, China
| | - Hong-Ping Cui
- Department of Ophthalmology, Shanghai East Hospital Affiliated to Tongji University, Shanghai 200120, China
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Wong RCY, Yu M, Chan TCY, Chong KKL, Jhanji V. Longitudinal comparison of outcomes after sub-Bowman keratomileusis and laser in situ keratomileusis: randomized, double-masked study. Am J Ophthalmol 2015; 159:835-45.e3. [PMID: 25681001 DOI: 10.1016/j.ajo.2015.02.003] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2014] [Revised: 02/04/2015] [Accepted: 02/04/2015] [Indexed: 11/29/2022]
Abstract
PURPOSE To compare the outcomes of sub-Bowman keratomileusis (100-μm flap) and laser in situ keratomileusis (LASIK) (120-μm flap) using 150-kHz femtosecond laser. DESIGN Randomized, double-masked, contralateral clinical trial. METHODS One hundred patients (200 eyes) with myopia or myopic astigmatism were included. Postoperative examinations were performed at week 1 and months 1, 3, 6, and 12. Main outcome measures included postoperative uncorrected (UCVA) and best-corrected distance visual acuity (BCVA); manifest refraction spherical equivalent; efficacy and safety indices; corneal thickness; and complications. RESULTS The mean age of patients was 33.9 ± 7.9 years. Overall, the preoperative UCVA, BCVA, and manifest refraction spherical equivalent were 1.349 ± 0.332, -0.022 ± 0.033, and -5.81 ± 1.61 diopters, respectively. No significant difference was observed in preoperative (P ≥ .226) or intraoperative parameters (P ≥ .452) between both groups, except residual stromal thickness (P < .001). The UCVA, manifest refraction spherical equivalent, and central corneal thickness stabilized by 1 week, while the thinnest corneal thickness stabilized by 3 months postoperatively. There was no significant difference between both groups for any parameter during all follow-up visits (P ≥ .132) except the 3-month safety index, which was better in the sub-Bowman keratomileusis group (P = .007). Soft opaque bubble layer was noted intraoperatively in 12 cases (7, 100-μm group; 5, 120-μm group; P = .577). No postoperative complications were observed. CONCLUSIONS Our study did not find any differences in the visual and refractive outcomes between femtosecond-assisted sub-Bowman keratomileusis and LASIK. Both surgeries resulted in quick visual recovery as early as 1 week postoperatively.
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Affiliation(s)
- Rachel Chung Yin Wong
- Department of Ophthalmology & Visual Sciences, The Chinese University of Hong Kong, Hong Kong, China
| | - Marco Yu
- Department of Mathematics and Statistics, Hang Seng Management College, Hong Kong, China
| | - Tommy C Y Chan
- Department of Ophthalmology & Visual Sciences, The Chinese University of Hong Kong, Hong Kong, China; Hong Kong Eye Hospital, Hong Kong, China
| | - Kelvin K L Chong
- Department of Ophthalmology & Visual Sciences, The Chinese University of Hong Kong, Hong Kong, China
| | - Vishal Jhanji
- Department of Ophthalmology & Visual Sciences, The Chinese University of Hong Kong, Hong Kong, China; Hong Kong Eye Hospital, Hong Kong, China.
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Sinha Roy A, Dupps WJ, Roberts CJ. Comparison of biomechanical effects of small-incision lenticule extraction and laser in situ keratomileusis: finite-element analysis. J Cataract Refract Surg 2014; 40:971-80. [PMID: 24857440 DOI: 10.1016/j.jcrs.2013.08.065] [Citation(s) in RCA: 136] [Impact Index Per Article: 13.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2013] [Revised: 07/12/2013] [Accepted: 08/14/2013] [Indexed: 11/18/2022]
Abstract
PURPOSE To theoretically compare the corneal stress distribution of laser in situ keratomileusis (LASIK) with the stress distribution of small-incision lenticule extraction. SETTING Cleveland Clinic Cole Institute, Cleveland, and The Ohio State University, Columbus, Ohio, USA. DESIGN Computational modeling study. METHODS A finite-element anisotropic collagen fiber-dependent model of myopic surgery using patient-specific corneal geometry was constructed for LASIK, small-incision lenticule extraction, and a geometry analog model with unaltered material properties from preoperative but with postoperative geometry including thickness. Surgical parameters, magnitude of myopic correction, LASIK flap thickness, and lenticule depth in small-incision lenticule extraction were varied. Two sets of models, 1 with uniform and 1 with depth-dependent material properties, were constructed. RESULTS Stress distribution between small-incision lenticule extraction simulations and the geometry analog model were similar. In contrast, LASIK consistently reduced stress in the flap and increased stress in the residual stromal bed (RSB) compared with the geometry analog model. An increase in flap thickness or lenticule depth resulted in a greater increase in RSB stress in the LASIK model than in the small-incision lenticule extraction model. CONCLUSIONS Small-incision lenticule extraction may present less biomechanical risk to the residual bed of susceptible corneas than comparable corrections involving LASIK flaps. Deeper corrections in the stroma may be possible in small-incision lenticule extraction without added risk for ectasia. FINANCIAL DISCLOSURES Proprietary or commercial disclosures are listed after the references.
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Affiliation(s)
- Abhijit Sinha Roy
- From the Cole Eye Institute (Sinha Roy, Dupps), Cleveland Clinic Foundation, the Department of Biomedical Engineering (Dupps), Lerner Research Institute, and the Department of Biomedical Engineering (Dupps), Case Western Reserve University, Cleveland, and the Departments of Ophthalmology and Biomedical Engineering (Roberts), The Ohio State University, Columbus, Ohio, USA
| | - William J Dupps
- From the Cole Eye Institute (Sinha Roy, Dupps), Cleveland Clinic Foundation, the Department of Biomedical Engineering (Dupps), Lerner Research Institute, and the Department of Biomedical Engineering (Dupps), Case Western Reserve University, Cleveland, and the Departments of Ophthalmology and Biomedical Engineering (Roberts), The Ohio State University, Columbus, Ohio, USA
| | - Cynthia J Roberts
- From the Cole Eye Institute (Sinha Roy, Dupps), Cleveland Clinic Foundation, the Department of Biomedical Engineering (Dupps), Lerner Research Institute, and the Department of Biomedical Engineering (Dupps), Case Western Reserve University, Cleveland, and the Departments of Ophthalmology and Biomedical Engineering (Roberts), The Ohio State University, Columbus, Ohio, USA.
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Katz T, Wagenfeld L, Galambos P, Darrelmann BG, Richard G, Linke SJ. LASIK versus photorefractive keratectomy for high myopic (> 3 diopter) astigmatism. J Refract Surg 2013; 29:824-31. [PMID: 24202704 DOI: 10.3928/1081597x-20131029-03] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2013] [Accepted: 08/05/2013] [Indexed: 11/20/2022]
Abstract
PURPOSE To compare the efficacy, safety, predictability, and vector analysis indices of LASIK and photorefractive keratectomy (PRK) for correction of high cylinder of greater than 3 diopters (D) in myopic eyes. METHODS The efficacy, safety, and predictability of LASIK or PRK performed in 114 consecutive randomly selected myopic eyes with an astigmatism of greater than 3 D were retrospectively analyzed at the 2- to 6-month follow-up visits. Vector analysis of the cylindrical correction was compared between the treatment groups. RESULTS A total of 57 eyes receiving PRK and 57 eyes receiving LASIK of 114 refractive surgery candidates were enrolled in the study. No statistically significant difference in efficacy [efficacy index = 0.76 (±0.32) for PRK vs 0.74 (±0.19) for LASIK (P = .82)], safety [safety index = 1.10 (±0.26) for PRK vs 1.01 (±0.17) for LASIK (P = .121)], or predictability [achieved astigmatism < 1 D in 39% of PRK- and 54% of LASIK-treated eyes, and < 2 D in 88% of PRK- and 89% of LASIK-treated eyes (P = .218)] was demonstrated. Using Alpins vector analysis, the surgically induced astigmatism and difference vector were not significantly different between the surgery methods, whereas the correction index showed a slight and significant advantage of LASIK over PRK (1.25 for PRK and 1.06 for LASIK, P < .001). CONCLUSIONS LASIK and PRK are comparably safe, effective, and predictable procedures for excimer laser correction of high astigmatism of greater than 3 D in myopic eyes. Predictability of the correction of the cylindrical component is lower than that of the spherical equivalent.
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The association between femtosecond laser flap parameters and ocular aberrations after uncomplicated custom myopic LASIK. Graefes Arch Clin Exp Ophthalmol 2013; 251:2155-62. [DOI: 10.1007/s00417-013-2328-1] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2012] [Revised: 03/06/2013] [Accepted: 03/13/2013] [Indexed: 10/27/2022] Open
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Farjo AA, Sugar A, Schallhorn SC, Majmudar PA, Tanzer DJ, Trattler WB, Cason JB, Donaldson KE, Kymionis GD. Femtosecond lasers for LASIK flap creation: a report by the American Academy of Ophthalmology. Ophthalmology 2012; 120:e5-e20. [PMID: 23174396 DOI: 10.1016/j.ophtha.2012.08.013] [Citation(s) in RCA: 99] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2012] [Accepted: 08/07/2012] [Indexed: 11/19/2022] Open
Abstract
OBJECTIVE To review the published literature to assess the safety, efficacy, and predictability of femtosecond lasers for the creation of corneal flaps for LASIK; to assess the reported outcomes of LASIK when femtosecond lasers are used to create corneal flaps; and to compare the differences in outcomes between femtosecond lasers and mechanical microkeratomes. METHODS Literature searches of the PubMed and Cochrane Library databases were last conducted on October 12, 2011, without language or date limitations. The searches retrieved a total of 636 references. Of these, panel members selected 58 articles that they considered to be of high or medium clinical relevance, and the panel methodologist rated each article according to the strength of evidence. Four studies were rated as level I evidence, 14 studies were rated as level II evidence, and the remaining studies were rated as level III evidence. RESULTS The majority of published studies evaluated a single laser platform. Flap reproducibility varied by device and the generation of the device. Standard deviations in flap thicknesses ranged from 4 to 18.4 μm. Visual acuities and complications reported with LASIK flaps created using femtosecond lasers are within Food and Drug Administration safety and efficacy limits. Of all complications, diffuse lamellar keratitis is the most common after surgery but is generally mild and self-limited. Corneal sensation was reported to normalize by 1 year after surgery. Unique complications of femtosecond lasers included transient light-sensitivity syndrome, rainbow glare, opaque bubble layer, epithelial breakthrough of gas bubbles, and gas bubbles within the anterior chamber. CONCLUSIONS Available evidence (levels I and II) indicates that femtosecond lasers are efficacious devices for creating LASIK flaps, with accompanying good visual results. Overall, femtosecond lasers were found to be as good as or better than mechanical microkeratomes for creating LASIK flaps. There are unique complications that can occur with femtosecond lasers, and long-term follow-up is needed to evaluate the technology fully.
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Affiliation(s)
| | - Alan Sugar
- Ophthalmology and Visual Sciences, W.K. Kellogg Eye Center, University of Michigan, Ann Arbor, Michigan
| | - Steven C Schallhorn
- University of California, San Francisco, California; Global Medical Director Optical Express; Gordon-Weiss-Schanzlin Vision Institute, San Diego, California
| | | | - David J Tanzer
- Gordon-Weiss-Schanzlin Vision Institute, San Diego, California
| | | | - John B Cason
- Ophthalmology Clinic, Naval Medical Center, San Diego, California
| | | | - George D Kymionis
- Institute of Vision and Optics (IVO), Faculty of Medicine, University of Crete, Heraklion, Crete, Greece
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Vaddavalli PK, Hurmeric V, Wang J, Yoo SH. Corneal haze following disruption of epithelial basement membrane on ultra-high-resolution OCT following femtosecond LASIK. J Refract Surg 2011; 28:72-4. [PMID: 22149771 DOI: 10.3928/1081597x-20111202-01] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2011] [Accepted: 10/13/2011] [Indexed: 11/20/2022]
Abstract
PURPOSE To analyze in vivo structural properties of a case with interface haze that developed after femtosecond laser-assisted LASIK. METHODS Case report. RESULTS A 42-year-old man underwent uncomplicated LASIK. Four months after the surgery he developed regression of his refractive error and interface haze in both eyes. Flap thickness was calculated as 73 μm and 81 μm in the right and left eyes, respectively. A novel ultra-high-resolution spectral domain optical coherence tomography (OCT) system was used to demonstrate in vivo morphology of the cornea. On ultra-high-resolution OCT, haze was demonstrated as increased bright white reflectivity of the flap interface. Areas of focal disruption of the basement membrane and Bowman layer corresponded with the most significant areas of interface haze. CONCLUSIONS Our results support the hypothesis that haze after femtosecond LASIK may be a result of damage to the basement membrane and Bowman layer of the cornea.
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Affiliation(s)
- Pravin K Vaddavalli
- Bascom Palmer Eye Institute, University of Miami, Miller School of Medicine, Miami, FL 33136, USA
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Moshirfar M, Betts BS, Churgin DS, Hsu M, Neuffer M, Sikder S, Church D, Mifflin MD. A prospective, randomized, fellow eye comparison of WaveLight® Allegretto Wave ® Eye-Q versus VISX CustomVue™ STAR S4 IR™ in laser in situ keratomileusis (LASIK): analysis of visual outcomes and higher order aberrations. Clin Ophthalmol 2011; 5:1339-47. [PMID: 22034553 PMCID: PMC3198407 DOI: 10.2147/opth.s24316] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
Abstract
Purpose To compare outcomes in visual acuity, refractive error, higher-order aberrations (HOAs), contrast sensitivity, and dry eye in patients undergoing laser in situ keratomileusis (LASIK) using wavefront (WF) guided VISX CustomVue and WF optimized WaveLight Allegretto platforms. Methods In this randomized, prospective, single-masked, fellow eye study, LASIK was performed on 44 eyes (22 patients), with one eye randomized to WaveLight Allegretto, and the fellow eye receiving VISX CustomVue. Postoperative outcome measures at 3 months included uncorrected distance visual acuity (UDVA), corrected distance visual acuity (CDVA), refractive error, root-mean-square (RMS) value of total and grouped HOAs, contrast sensitivity, and Schirmers testing. Results Mean values for UDVA (logMAR) were −0.067 ± 0.087 and −0.073 ± 0.092 in the WF optimized and WF guided groups, respectively (P = 0.909). UDVA of 20/20 or better was achieved in 91% of eyes undergoing LASIK with both lasers while UDVA of 20/15 or better was achieved in 64% of eyes using the Allegretto platform, and 59% of eyes using VISX CustomVue (P = 1.000). In the WF optimized group, total HOA increased 4% (P = 0.012), coma increased 11% (P = 0.065), and spherical aberration increased 19% (P = 0.214), while trefoil decreased 5% (P = 0.490). In the WF guided group, total HOA RMS decreased 9% (P = 0.126), coma decreased 18% (P = 0.144), spherical aberration decreased 27% (P = 0.713) and trefoil decreased 19% (P = 0.660). One patient lost one line of CDVA secondary to residual irregular astigmatism. Conclusion Both the WaveLight Allegretto and the VISX CustomVue platforms had equal visual and safety outcomes. Most wavefront optimized HOA values trended upward, with a statistically significant increase in total HOA RMS. Eyes treated with the WF guided platform showed a decreasing trend in HOA values.
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Affiliation(s)
- Majid Moshirfar
- John A Moran Eye Center, Department of Ophthalmology and Visual Sciences, University of Utah, Salt Lake City, UT, USA.
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Abstract
PURPOSE OF REVIEW The corneal flap laser in-situ keratomileusis (LASIK) is among the most important determinants in the successful outcome of the surgery. Femtosecond lasers have evolved over the last decade to all but replace the mechanical microkeratome as the preferred method to create these flaps. With improvements in femtosecond laser technology, there has been a reduction in the time taken for the cut and the quality of the stromal bed has improved. Improved predictability has led surgeons to explore the possibility of thin flap LASIK. RECENT FINDINGS Corneal flaps created with the femtosecond laser have been shown to be more predictable in depth and have a more desirable planar morphology. Corneal flaps created by the femtosecond laser can be customized according to depth, profile, morphology, and side-cut configuration. Changes in the angulation of the side cut, to reduce the incidence of epithelial ingrowth, have not been corroborated by clinical evidence as yet. Thin flap LASIK, also referred to as sub-Bowman's keratomileusis, has the advantage of preserving more stroma and potentially reducing the incidence of corneal ectasia but seems to be associated with an increased incidence of interface haze. SUMMARY This review examines the advantages of creating a flap with the femtosecond laser and the various configurations of these flaps. It also explores the advantages of varying the thickness and profile of femtosecond flaps.
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Moshirfar M, Churgin DS, Betts BS, Hsu M, Sikder S, Neuffer M, Church D, Mifflin MD. Prospective, randomized, fellow eye comparison of WaveLight Allegretto Wave Eye-Q versus VISX CustomVueTM STAR S4 IRTM in photorefractive keratectomy: analysis of visual outcomes and higher-order aberrations. Clin Ophthalmol 2011; 5:1185-93. [PMID: 21966184 PMCID: PMC3180481 DOI: 10.2147/opth.s24319] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
Abstract
Background The purpose of this study was to compare differences in visual outcomes, higher-order aberrations, contrast sensitivity, and dry eye in patients undergoing photorefractive keratectomy using wavefront-guided VISX CustomVue™ and wavefront-optimized WaveLight® Allegretto platforms. Methods In this randomized, prospective, single-masked, fellow-eye study, photorefractive keratectomy was performed on 46 eyes from 23 patients, with one eye randomized to WaveLight Allegretto, and the fellow eye receiving VISX CustomVue. Three-month postoperative outcome measures included uncorrected distance visual acuity, corrected distance visual acuity, refractive error, root mean square of total and grouped higher-order aberrations, contrast sensitivity, and Schirmer’s testing. Results Mean values for uncorrected distance visual acuity (logMAR) were −0.03 ± 0.07 and −0.06 ± 0.09 in the wavefront-optimized and wavefront-guided groups, respectively (P = 0.121). Uncorrected distance visual acuity of 20/20 or better was achieved in 91% of eyes receiving wavefront-guided photorefractive keratectomy, and 87% of eyes receiving wavefront-optimized photorefractive keratectomy, whereas uncorrected distance visual acuity of 20/15 was achieved in 35% of the wavefront-optimized group and 64% of the wavefront-guided group (P ≥ 0.296). While root mean square of total higher-order aberration, coma, and trefoil tended to increase in the wavefront-optimized group (P = 0.091, P = 0.115, P = 0.459, respectively), only spherical aberration increased significantly (P = 0.014). Similar increases were found in wavefront- guided root mean square of total higher-order aberration (P = 0.113), coma (P = 0.403), trefoil (P = 0.603), and spherical aberration (P = 0.014). There was no significant difference in spherical aberration change when comparing the two platforms. The wavefront-guided group showed an increase in contrast sensitivity at 12 cycles per degree (P = 0.013). Conclusion Both VISX CustomVue and WaveLight Allegretto platforms performed equally in terms of visual acuity, safety, and predictability in photorefractive keratectomy. The wavefront-guided group showed slightly improved contrast sensitivity. Both lasers induced a comparable degree of statistically significant spherical aberration, and tended to increase other higher-order aberration measures as well.
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Affiliation(s)
- Majid Moshirfar
- University of Utah, John A Moran Eye Center, Department of Ophthalmology and Visual Sciences, Salt Lake City, UT, USA
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Bibliography. Refractive surgery. Current world literature. Curr Opin Ophthalmol 2011; 22:304-5. [PMID: 21654397 DOI: 10.1097/icu.0b013e3283486839] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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Hatch BB, Moshirfar M, Ollerton AJ, Sikder S, Mifflin MD. A prospective, contralateral comparison of photorefractive keratectomy (PRK) versus thin-flap LASIK: assessment of visual function. Clin Ophthalmol 2011; 5:451-7. [PMID: 21573091 PMCID: PMC3090298 DOI: 10.2147/opth.s18967] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2011] [Indexed: 11/28/2022] Open
Abstract
Purpose: To compare differences in visual acuity, contrast sensitivity, complications, and higher-order ocular aberrations (HOAs) in eyes with stable myopia undergoing either photo-refractive keratectomy (PRK) or thin-flap laser in situ keratomileusis (LASIK) (intended flap thickness of 90 μm) using the VISX Star S4 CustomVue excimer laser and the IntraLase FS60 femtosecond laser at 1, 3, and 6 months postoperatively. Methods: In this prospective, masked, and randomized pilot study, refractive surgery was performed contralaterally on 52 eyes: 26 with PRK and 26 with thin-flap LASIK. Primary outcome measures were uncorrected distance visual acuity (UDVA), corrected distance visual acuity (CDVA), contrast sensitivity, and complications. Results: At 6 months, mean values for UDVA (logMAR) were −0.043 ± 0.668 and −0.061 ± 0.099 in the PRK and thin-flap LASIK groups, respectively (n = 25, P = 0.466). UDVA of 20/20 or better was achieved in 96% of eyes undergoing PRK and 92% of eyes undergoing thin-flap LASIK, whereas 20/15 vision or better was achieved in 73% of eyes undergoing PRK and 72% of eyes undergoing thin-flap LASIK (P > 0.600). Significant differences were not found between treatment groups in contrast sensitivity (P ≥ 0.156) or CDVA (P = 0.800) at postoperative 6 months. Types of complications differed between groups, notably 35% of eyes in the thin-flap LASIK group experiencing complications, including microstriae and 2 flap tears. Conclusion: Under well-controlled surgical conditions, PRK and thin-flap LASIK refractive surgeries achieve similar results in visual acuity, contrast sensitivity, and induction of HOAs, with differences in experienced complications.
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Affiliation(s)
- Bryndon B Hatch
- John A. Moran Eye Center, University of Utah, Salt Lake City, UT, USA
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