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Tamimi A, Sheikhzadeh F, Ezabadi SG, Islampanah M, Parhiz P, Fathabadi A, Poudineh M, Khanjani Z, Pourmontaseri H, Orandi S, Mehrabani R, Rahmanian M, Deravi N. Post-LASIK dry eye disease: A comprehensive review of management and current treatment options. Front Med (Lausanne) 2023; 10:1057685. [PMID: 37113611 PMCID: PMC10126282 DOI: 10.3389/fmed.2023.1057685] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2022] [Accepted: 03/14/2023] [Indexed: 04/29/2023] Open
Abstract
Laser-assisted in situ keratomileusis (LASIK) is a unique corneal stromal laser ablation method that uses an excimer laser to reach beneath corneal dome-shaped tissues. In contrast, surface ablation methods, such as photorefractive keratectomy, include removing epithelium and cutting off the Bowman's layer and the stromal tissue of the anterior corneal surface. Dry eye disease (DED) is the most common complication after LASIK. DED is a typical multi-factor disorder of the tear function and ocular surface that occurs when the eyes fail to produce efficient or adequate volumes of tears to moisturize the eyes. DED influences quality of life and visual perception, as symptoms often interfere with daily activities such as reading, writing, or using video display monitors. Generally, DED brings about discomfort, symptoms of visual disturbance, focal or global tear film instability with possible harm to the ocular surface, the increased osmolarity of the tear film, and subacute inflammation of the ocular surface. Almost all patients develop a degree of dryness in the postoperative period. Detection of preoperative DED and committed examination and treatment in the preoperative period, and continuing treatments postoperatively lead to rapid healing, fewer complications, and improved visual outcomes. To improve patient comfort and surgical outcomes, early treatment is required. Therefore, in this study, we aim to comprehensively review studies on the management and current treatment options for post-LASIK DED.
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Affiliation(s)
- Atena Tamimi
- Student Research Committee, School of Medicine, Shahid Beheshti University of Medical Sciences, Tehran, Iran
| | | | - Sajjad Ghane Ezabadi
- Students’ Scientific Research Center, School of Medicine, Tehran University of Medical Sciences, Tehran, Iran
| | | | - Peyman Parhiz
- Student Research Committee, Zahedan Medical Sciences Branch, Islamic Azad University, Zahedan, Iran
| | - Amirhossein Fathabadi
- Student Research Committee, School of Paramedical Sciences, Mashhad University of Medical Sciences, Mashhad, Iran
| | | | - Zahra Khanjani
- Student Research Committee, School of Medicine, Shahid Beheshti University of Medical Sciences, Tehran, Iran
| | - Hossein Pourmontaseri
- Student Research Committee, Fasa University of Medical Sciences, Fasa, Iran
- Bitab Knowledge Enterprise, Fasa University of Medical Sciences, Fasa, Iran
| | - Shirin Orandi
- Department of Clinical Biochemistry, School of Medicine, Tehran University of Medical Sciences, Tehran, Iran
| | - Reyhaneh Mehrabani
- Student Research Committee, Semnan University of Medical Sciences, Semnan, Iran
| | - Mohammad Rahmanian
- Student Research Committee, School of Medicine, Shahid Beheshti University of Medical Sciences, Tehran, Iran
| | - Niloofar Deravi
- Student Research Committee, School of Medicine, Shahid Beheshti University of Medical Sciences, Tehran, Iran
- *Correspondence: Niloofar Deravi,
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Soeken TA, Ross AE, Kohane DS, Kuang L, Legault GL, Caldwell MC, Brundridge WL, Merkley MB, Ciolino JB, Townley JR. Dexamethasone-Eluting Contact Lens for the Prevention of Postphotorefractive Keratectomy Scar in a New Zealand White Rabbit Model. Cornea 2021; 40:1175-1180. [PMID: 34294635 DOI: 10.1097/ico.0000000000002711] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2020] [Accepted: 01/28/2021] [Indexed: 11/25/2022]
Abstract
PURPOSE To evaluate the safety and efficacy of an experimental dexamethasone-eluting contact lens (DCL) for the prevention of postphotorefractive keratectomy (PRK) corneal haze in a New Zealand White (NZW) rabbit model. METHODS Both eyes of 29 NZW rabbits underwent PRK. The rabbits were randomized to one of the 5 study arms for 4 weeks: tarsorrhaphy only, tarsorrhaphy and bandage contact lens (BCL) replaced weekly, tarsorrhaphy and BCL for 1 week plus topical 0.1% dexamethasone ophthalmic solution (drops) for 4 weeks, tarsorrhaphy and BCL replaced weekly plus topical dexamethasone for 4 weeks, and tarsorrhaphy and DCL changed weekly for 4 weeks. Each week for 4 consecutive weeks postoperatively, the tarsorrhaphies were opened, the eyes underwent evaluation and imaging, and the tarsorrhaphies were replaced. Contact lenses were cultured on removal. Central corneal haze was assessed weekly with corneal densitometry. After 4 weeks, the animals were killed, and the eyes were enucleated for histopathologic analysis. RESULTS The tarsorrhaphy only group displayed more haze with a greater change in optical densitometry from pre-op compared with the other treatment groups. There was no difference between the DCL group and the groups receiving a BCL and dexamethasone drops in densitometry or histopathology. No NZW rabbits developed clinical signs of infection, and cultures from DCLs and BCLs grew similar organisms. CONCLUSIONS In the post-PRK rabbit model, DCLs worn weekly for 4 weeks were safe and as effective at preventing corneal haze as 0.1% dexamethasone drops applied 4 times a day for 4 weeks.
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Affiliation(s)
- Timothy A Soeken
- Department of Ophthalmology, San Antonio Uniformed Services Health Education Consortium, San Antonio, TX
| | - Amy E Ross
- Department of Ophthalmology, Massachusetts Eye and Ear Infirmary, Harvard Medical School, Boston, MA
| | - Daniel S Kohane
- Laboratory for Biomaterials and Drug Delivery, Department of Anesthesiology, Division of Critical Care Medicine, Boston Children's Hospital, Harvard Medical School, Boston, MA; and
| | - Liangju Kuang
- Department of Ophthalmology, Massachusetts Eye and Ear Infirmary, Harvard Medical School, Boston, MA
| | - Gary L Legault
- Department of Ophthalmology, San Antonio Uniformed Services Health Education Consortium, San Antonio, TX
| | - Matthew C Caldwell
- Department of Ophthalmology, San Antonio Uniformed Services Health Education Consortium, San Antonio, TX
| | - Wesley L Brundridge
- Department of Ophthalmology, San Antonio Uniformed Services Health Education Consortium, San Antonio, TX
| | - Michael B Merkley
- Department of Ophthalmology, San Antonio Uniformed Services Health Education Consortium, San Antonio, TX
| | - Joseph B Ciolino
- Department of Ophthalmology, Massachusetts Eye and Ear Infirmary, Harvard Medical School, Boston, MA
- Laboratory for Biomaterials and Drug Delivery, Department of Anesthesiology, Division of Critical Care Medicine, Boston Children's Hospital, Harvard Medical School, Boston, MA; and
- Departments of Anesthesia and Surgery, Boston Children's Hospital, Harvard Medical School, Boston, MA
| | - J Richard Townley
- Department of Ophthalmology, San Antonio Uniformed Services Health Education Consortium, San Antonio, TX
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Ang M, Gatinel D, Reinstein DZ, Mertens E, Alió Del Barrio JL, Alió JL. Refractive surgery beyond 2020. Eye (Lond) 2020; 35:362-382. [PMID: 32709958 DOI: 10.1038/s41433-020-1096-5] [Citation(s) in RCA: 64] [Impact Index Per Article: 16.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2020] [Revised: 05/19/2020] [Accepted: 07/08/2020] [Indexed: 02/07/2023] Open
Abstract
Refractive surgery refers to any procedure that corrects or minimizes refractive errors. Today, refractive surgery has evolved beyond the traditional laser refractive surgery, embodied by the popular laser in situ keratomileusis or 'LASIK'. New keratorefractive techniques such as small incision lenticule extraction (SMILE) avoids corneal flap creation and uses a single laser device, while advances in surface ablation techniques have seen a resurgence in its popularity. Presbyopic treatment options have also expanded to include new ablation profiles, intracorneal implants, and phakic intraocular implants. With the improved safety and efficacy of refractive lens exchange, a wider variety of intraocular lens implants with advanced optics provide more options for refractive correction in carefully selected patients. In this review, we also discuss possible developments in refractive surgery beyond 2020, such as preoperative evaluation of refractive patients using machine learning and artificial intelligence, potential use of stromal lenticules harvested from SMILE for presbyopic treatments, and various advances in intraocular lens implants that may provide a closer to 'physiological correction' of refractive errors.
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Affiliation(s)
- Marcus Ang
- Singapore Eye Research Institute, Singapore National Eye Centre, Singapore, Singapore. .,Department of Ophthalmology and Visual Science, Duke-NUS Graduate Medical School, Singapore, Singapore.
| | | | - Dan Z Reinstein
- London Vision Clinic, London, UK.,Department of Ophthalmology, Columbia University Medical Center, New York, NY, USA.,Sorbonne Université, Paris, France.,Biomedical Science Research Institute, Ulster University, Belfast, UK
| | - Erik Mertens
- Medipolis-Antwerp Private Clinic, Antwerp, Belgium
| | - Jorge L Alió Del Barrio
- Division of Ophthalmology, School of Medicine, Universidad Miguel Hernández, Alicante, Spain.,Cornea, Cataract and Refractive Surgery Unit, Vissum (Miranza Group), Alicante, Spain
| | - Jorge L Alió
- Division of Ophthalmology, School of Medicine, Universidad Miguel Hernández, Alicante, Spain.,Cornea, Cataract and Refractive Surgery Unit, Vissum (Miranza Group), Alicante, Spain
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Kim TI, Alió Del Barrio JL, Wilkins M, Cochener B, Ang M. Refractive surgery. Lancet 2019; 393:2085-2098. [PMID: 31106754 DOI: 10.1016/s0140-6736(18)33209-4] [Citation(s) in RCA: 179] [Impact Index Per Article: 35.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/30/2018] [Revised: 11/29/2018] [Accepted: 12/11/2018] [Indexed: 01/19/2023]
Abstract
Refractive surgery has evolved beyond laser refractive techniques over the past decade. Laser refractive surgery procedures (such as laser in-situ keratomileusis), surface ablation techniques (such as laser epithelial keratomileusis), and photorefractive keratectomy have now been established as fairly safe procedures that produce excellent visual outcomes for patients with low-to-moderate amounts of ametropia. Additionally, a broader selection of options are now available to treat a wider range of refractive errors. Small incision lenticule extraction uses a femtosecond laser to shape a refractive lenticule, which is removed through a small wound. The potential advantages of this procedure include greater tectonic strength and less dry eye. In the future, intracorneal implants could be used to treat hyperopia or presbyopia. Phakic intraocular implants and refractive lens exchange might be useful options in carefully selected patients for correcting high degrees of ametropia. Thus, physicians are now able to provide patients with the appropriate refractive corrective option based on the individual's risk-benefit profile.
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Affiliation(s)
- Tae-Im Kim
- Department of Ophthalmology, The Institute of Vision Research, Yonsei University College of Medicine, Seoul, South Korea
| | - Jorge L Alió Del Barrio
- Cornea, Cataract and Refractive Surgery Unit, Research & Development Department VISSUM Innovation Alicante, Alicante, Spain; Division of Ophthalmology, School of Medicine, Universidad Miguel Hernández, Alicante, Spain
| | - Mark Wilkins
- Department of Ophthalmology, Moorfields Eye Hospital, London, UK
| | - Beatrice Cochener
- Department of Ophthalmology, University Hospital Morvan, Brest, France
| | - Marcus Ang
- Singapore Eye Research Institute, Singapore National Eye Centre, Singapore; Department of Ophthalmology and Visual Science, Duke-NUS Graduate Medical School, Singapore.
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Merayo-Lloves J, Blanco-Mezquita T, Ibares-Frías L, Fabiani L, Alvarez-Barcia A, Martinez-García C. Induction of Controlled Wound Healing with PMMA Segments in the Deep Stroma in Corneas of Hens. Eur J Ophthalmol 2018; 20:62-70. [DOI: 10.1177/112067211002000108] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
Purpose Polymethylmethacrylate (PMMA) segments are normally used in additive surgery to treat both corneal ectasia post laser-assisted in situ keratomileusis and keratoconus. The aim of this work was to develop an experimental animal model to induce wound healing in the deep stroma in corneas of hens. Methods PMMA segments were implanted in the right eyes of 40 adult hens without suture in the wound incision. Animals were randomized for 5 time points to histopathology study (1, 3, 15, 30, and 90 days) being clinically evaluated during the experiment. Results Thirty-four eyes (85%) had a successful clinical outcome and intraoperative mistakes occurred in 6 eyes (15%), including anterior chamber perforation resulting in abscess (1), excess of lamellar dissection with segment migration (3), and peripheral incisions evolving with neovascularization (2). At 24 hours, all the epithelial injuries were completed in integrity, but a persistent stromal incision, with a fish mouth form, was observed until day 15. Corneal edema disappeared at the fifth day. Haze, keratocyte cell death, keratocyte proliferation, myofibroblast differentiation, and new matrix production were observed in length around the segment. Conclusions Wound healing was induced in the deep corneal stroma by means of PMMA segment implantation in a new animal model developed in hens.
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Absence of IL-6 prevents corneal wound healing after deep excimer laser ablation in vivo. Eye (Lond) 2017; 32:156-157. [PMID: 29099496 DOI: 10.1038/eye.2017.238] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022] Open
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Richmond CJ, Barker PD, Levine EM, Hofmeister EM. Laser in situ keratomileusis flap stability in an aviator following aircraft ejection. J Cataract Refract Surg 2016; 42:1681-1683. [PMID: 27956297 DOI: 10.1016/j.jcrs.2016.10.001] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2016] [Accepted: 09/15/2016] [Indexed: 10/20/2022]
Abstract
We present the case of a 28-year-old male F/A-18F Super Hornet naval flight officer who ejected from an aircraft at 13 000 feet at a speed in excess of 350 knots 7 years after uneventful laser in situ keratomileusis (LASIK). The patient was evaluated the day after the ejection. No LASIK flap complications or epithelial defects were found, and the corrected distance visual acuity was 20/15 in both eyes. FINANCIAL DISCLOSURE None of the authors has a financial or proprietary interest in any material or method mentioned.
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Affiliation(s)
- Christopher J Richmond
- From Carrier Air Wing ONE (Richmond), Branch Health Clinic Naval Air Station Oceana, Virginia Beach, the Department of Ophthalmology (Barker, Levine), Naval Medical Center Portsmouth, Portsmouth, Virginia, and the Department of Ophthalmology (Hofmeister), Naval Medical Center San Diego, San Diego, California, USA
| | - Patrick D Barker
- From Carrier Air Wing ONE (Richmond), Branch Health Clinic Naval Air Station Oceana, Virginia Beach, the Department of Ophthalmology (Barker, Levine), Naval Medical Center Portsmouth, Portsmouth, Virginia, and the Department of Ophthalmology (Hofmeister), Naval Medical Center San Diego, San Diego, California, USA.
| | - Edgar M Levine
- From Carrier Air Wing ONE (Richmond), Branch Health Clinic Naval Air Station Oceana, Virginia Beach, the Department of Ophthalmology (Barker, Levine), Naval Medical Center Portsmouth, Portsmouth, Virginia, and the Department of Ophthalmology (Hofmeister), Naval Medical Center San Diego, San Diego, California, USA
| | - Elizabeth M Hofmeister
- From Carrier Air Wing ONE (Richmond), Branch Health Clinic Naval Air Station Oceana, Virginia Beach, the Department of Ophthalmology (Barker, Levine), Naval Medical Center Portsmouth, Portsmouth, Virginia, and the Department of Ophthalmology (Hofmeister), Naval Medical Center San Diego, San Diego, California, USA
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Long term followup of photorefractive keratectomy with adjuvant use of mitomycin C. J Ophthalmol 2014; 2014:821920. [PMID: 24868456 PMCID: PMC4020169 DOI: 10.1155/2014/821920] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2013] [Accepted: 03/13/2014] [Indexed: 11/22/2022] Open
Abstract
Purpose. To study the long term refractive and visual outcomes of photorefractive keratectomy (PRK) with intraoperative application of mitomycin C (MMC). Methods. This study included 37 eyes who received myopic PRK; after photoablation, a sponge soaked in 0.02% MMC solution was applied in all corneas for 2 minutes. Efficacy, safety, predictability, and stability of PRK MMC were evaluated. Endothelial cell density was evaluated at the last postoperative interval. Results. Mean preoperative spherical equivalent (SEQ) was −6.03 ± 1.87 D (diopters) and reduced to −0.09 ± 0.53 D at the last postoperative examination. Mean followup was 44.73 ± 18.24 months. All the eyes were in the ±1.00 D of attempted versus achieved SEQ at the one-year follow-up interval. Furthermore, 95% of the eyes did not lose lines or gained 1 to 2 lines of CDVA, while 5% lost 1 line. At the third postoperative month, 89% of the eyes either were clear or had trace haze, while 4 eyes had mild haze; by the 12-month postoperative interval, none of the eyes demonstrated haze. Mean endothelial cell density (ECD) at the last postoperative interval was 2658 ± 153 cells/mm2. Conclusions. PRK, with intraoperative use of MMC, demonstrates stable refractive and visual outcomes up to 44 months after surgery.
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Contralateral-eye study of surface refractive treatments: Clinical and confocal microscopy evaluation. J Cataract Refract Surg 2014; 40:224-31. [DOI: 10.1016/j.jcrs.2013.07.049] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2013] [Revised: 07/23/2013] [Accepted: 07/25/2013] [Indexed: 11/18/2022]
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A microscopy study of the structural features of post-LASIK human corneas. PLoS One 2013; 8:e63268. [PMID: 23650559 PMCID: PMC3641130 DOI: 10.1371/journal.pone.0063268] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2012] [Accepted: 03/30/2013] [Indexed: 11/28/2022] Open
Abstract
Purpose To study the structural features of human post-LASIK corneas. Methods A pair of post-mortem donor corneas, from a 55-year old patient who underwent uncomplicated LASIK surgery five years previously, were bisected and fixed in 4% paraformaldehyde. The right cornea and one half of the left cornea were processed for light microscopy and scanning electron microscopy. One half of the right cornea was also examined by transmission electron microscopy. Results The flap-bed interface could be easily detected several years after LASIK and, although the flap appeared to be in close association with the stromal bed, there was a noticeable absence of reconnection between adjacent severed lamellae. Tissue gaps were evident at the flap margin, which once free of cellular components revealed the presence of a few bridging fibres. Conclusion Examination of corneas five years after LASIK revealed evidence of primitive reparative scar development at the wound interface, but no reconnection of severed collagen lamellae. Such findings may explain the occurrence of flap dislocation following trauma in some patients months or years after surgery.
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Ivarsen A, Møller-Pedersen T. LASIK Induces Minimal Regrowth and No Haze Development in Rabbit Corneas. Curr Eye Res 2009; 30:363-73. [PMID: 16020267 DOI: 10.1080/02713680590964848] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
Abstract
PURPOSE To quantify central corneal regrowth and haze development after LASIK in rabbits. METHODS New Zealand White rabbits received an 89 microm (-8 diopters) myopic LASIK and were evaluated during 4 months using slit-lamp and in vivo confocal microscopy to monitor changes in central corneal morphology, epithelial and stromal thickness, flap and bed thickness, and corneal light backscattering (haze). At various time-points, corneas were processed for histology. RESULTS Using in vivo confocal microscopy, LASIK induced no detectable morphological changes besides a slightly elevated light backscattering at the interface. Correspondingly, all corneas remained clear with no haze development by slit-lamp biomicroscopy. Corneal thickness was stable by 8 weeks after an increase of 17 +/- 4 microm that consisted of a 13 +/- 3 microm stromal regrowth and a 4 +/- 2 microm epithelial hyperplasia. At the LASIK interface, less than 4 microm new extracellular matrix was deposited. Accordingly, all LASIK flaps were easily pulled off by 6 months. CONCLUSIONS LASIK induces a minimal wound healing response in rabbit corneas with no haze development and a regrowth (regression) of only 17 microm of an 89-microm photoablation. Three main factors contributed to the observed regrowth: epithelial hyperplasia (approximately 4 microm), matrix deposition at the LASIK interface (approximately 4 microm), and stromal growth outside the interface within the flap and wound bed (approximately 9 microm).
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Affiliation(s)
- Anders Ivarsen
- Department of Ophthalmology, Aarhus University Hospital, Denmark
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MøSller-Pedersen T, Cavanagh HD, Petroll WM, Jester JV. Neutralizing antibody to TGFβmodulates stromal fibrosis but not regression of photoablative effect following PRK. Curr Eye Res 2009. [DOI: 10.1080/02713689808951251] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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Esquenazi S, Esquenazi I, Grunstein L, He J, Bazan H. Immunohistological Evaluation of the Healing Response at the Flap Interface in Patients with LASIK Ectasia Requiring Penetrating Keratoplasty. J Refract Surg 2009; 25:739-46. [DOI: 10.3928/1081597x-20090707-09] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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Effect of excimer laser repetition rate on outcomes after photorefractive keratectomy. J Cataract Refract Surg 2008; 34:916-9. [PMID: 18498995 DOI: 10.1016/j.jcrs.2008.02.022] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2007] [Accepted: 02/04/2008] [Indexed: 11/22/2022]
Abstract
PURPOSE To compare the refractive outcomes after photorefractive keratectomy (PRK) for low to moderate myopic corrections using 2 excimer lasers with different repetition rates (200 Hz and 400 Hz). SETTING University refractive surgery center. METHODS This retrospective study included all consecutive patients who underwent PRK using the 200 Hz or the 400 Hz Allegretto laser platform (WaveLight Laser Technologie AG). Thirty-five patients (70 eyes) and 29 patients (58 eyes) had PRK with the 200 Hz platform and the 400 Hz platform, respectively, using the same surgical technique. RESULTS The mean follow-up was 13.22 months +/- 1.16 (SD) (range 11 to 15 months). No intraoperative or early postoperative (eg, late reepithelialization) complications were found in either group. At 1 year, 66 eyes (94.2%) in the 200 Hz group and 56 eyes (96.6%) in the 400 Hz group were within +/-1.00 diopter of the attempted correction. At 3 months, 20 eyes (29%) in the 200 Hz group and 27 eyes (46%) in the 400 Hz group had mild or moderate corneal haze (P = .03). These corneas showed progressive clearing over subsequent months without statistically significant differences in haze formation between the 2 groups. Twelve months after PRK, all corneas in both groups were clear. CONCLUSION Photorefractive keratectomy for the treatment of low to moderate refractive errors using a 200 Hz or 400 Hz excimer laser gave comparable results.
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Diakonis VF, Pallikaris A, Kymionis GD, Markomanolakis MM. Alterations in endothelial cell density after photorefractive keratectomy with adjuvant mitomycin. Am J Ophthalmol 2007; 144:99-103. [PMID: 17509511 DOI: 10.1016/j.ajo.2007.03.039] [Citation(s) in RCA: 45] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2007] [Revised: 03/19/2007] [Accepted: 03/23/2007] [Indexed: 11/27/2022]
Abstract
PURPOSE To elucidate the distinct role of the intraoperative use of mitomycin C (MMC) on endothelial cell density after photorefractive keratectomy (PRK) in human eyes. DESIGN Prospective, double-masked, randomized clinical trial. METHODS One eye of 15 patients was treated with PRK with intraoperative use of topical 0.02% MMC (15 seconds), whereas the fellow eye was treated with Epipolis laser in situ keratomileusis (Epi-LASIK) in random order. Corneal confocal microscopy was performed in all eyes preoperatively and at one, three, six, and 12 months after the surgery. Moreover, three endothelial images were acquired in each of 15 preoperative-normal eyes to evaluate the repeatability of measuring endothelial cell density. Repeated measures analysis of variance was used to compare the temporal variations of endothelial cell density between the two techniques and the changes of endothelial cell density over time. RESULTS The coefficient of repeatability of endothelial cell count was 148 cells/mm(2). Preoperative endothelial cell density was not significantly different between the two groups (P = .82). Moreover, the effect of the treatment on the temporal variation of endothelial cell density was insignificant (P = .83), whereas the differences between the preoperative and the postoperative endothelial cell densities reached statistical significance (P <or= .05). Nonetheless, inclusion of the repeatability of the instrument on the analysis diminished these significant differences (P > .05). CONCLUSIONS The prophylactic intraoperative application of MMC (up to 15 seconds) after PRK does not seem to affect the endothelial cell density.
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Affiliation(s)
- Vasilios F Diakonis
- Institute of Vision and Optics, University of Crete, Heraklion, Crete, Greece.
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Wang Y, He J, Kanxing Z, Jin Y, Zuo T, Wang W. Optical Quality Analysis After Surface Excimer Laser Ablation: The Relationship Between Wavefront Aberration and Subepithelial Haze. J Refract Surg 2006; 22:S1031-6. [PMID: 17444089 DOI: 10.3928/1081-597x-20061102-05] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
PURPOSE To investigate the relationship between mild and moderate corneal haze and the distribution of higher order wavefront aberrations after photorefractive keratectomy (PRK). METHODS Thirty-six eyes from 18 patients who underwent PRK were divided into two groups: 10 eyes with corneal haze and 26 eyes without corneal haze (control). All eyes were evaluated up to 6 months after PRK. Wavefront aberrations were measured using a psychophysical wavefront sensor and the NIDEK OPD-Scan. Topography, point spread function, and modulation transfer function maps were obtained from the OPD-Scan. RESULTS The mean total higher order aberration was slightly higher in the corneal haze group than in the control group. This difference was not statistically significant. The mean third order coma aberrations were higher and mean fourth order spherical aberrations were lower in the haze group compared with the control group, although neither difference attained statistical significance. The t test values were 1.05, -0.38, -1.10, -0.08, and -0.23, when comparing the mean third, fourth, fifth, sixth, and seventh order aberrations, respectively. None of these differences attained statistical significance. In terms of Zernike coefficients, Z-1 and Z1 showed greater mean root-mean-square (RMS) in the haze group (0.33 and 0.35 microm, respectively) than those for the control group (0.26 and 0.23 microm, respectively) (t=0.71 and P=.49; t=0.84 and P=.43, respectively). However, ZO had lower RMS in the haze group (0.18 microm) than in the control group (0.28 microm). This difference also was not statistically significant. CONCLUSIONS In this study comparing the optical aberrations of eyes with and without corneal haze after PRK, corneal haze did not affect the magnitude and distribution of higher order aberrations in a predictable manner.
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Affiliation(s)
- Yan Wang
- Refractive Surgery Center, Tianjin Eye Institute and Hospital, Teaching Hospital of Tianjin Medical University, Tianjin, China.
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Wang IJ, Sun YC, Lee YC, Hou YC, Hu FR. The relationship between anterior corneal aberrations and contrast sensitivity in conventional LASIK. Curr Eye Res 2006; 31:563-8. [PMID: 16877264 DOI: 10.1080/02713680600814761] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
Abstract
PURPOSE To evaluate the changes of anterior corneal aberrations before and after laser in situ keratomileusis (LASIK) and to assess the correlation between contrast sensitivity and anterior corneal aberrations. METHODS Right eyes of 51 patients including 6 males and 45 females undergoing conventional LASIK from September 2000 to July 2003 were enrolled. The calculation of anterior corneal aberrations before and after LASIK was obtained by analyzing the corneal topography from TMS-1 by using VOL-CT Version 6.23 software. Contrast sensitivity was measured after LASIK with an MCT 8000 under daytime and nighttime settings and with glare conditions. The differences of the Zernike coefficients and root mean square (RMS) of anterior corneal aberrations before and after LASIK were analyzed. The changes of contrast sensitivity at 1.5, 3, 6, 12, and 18 cpd were added separately for daytime and nighttime contrast sensitivity with and without glare after LASIK and were correlated with the changes of anterior corneal aberrations. RESULTS Vertical coma, RMS of coma-like RMS of spherical-like, RMS of trefoil-like and RMS of higher-order anterior corneal aberrations increased significantly after LASIK surgery. There were no significant correlations between the changes of anterior corneal aberrations and the changes of contrast sensitivity at daytime and nighttime, with and without glare. Contrast sensitivity at daytime and nighttime decreased at each spatial frequency after LASIK. CONCLUSIONS LASIK surgery induces changes of the anterior corneal aberrations. However, changes in anterior corneal aberrations did not correlate with the changes of contrast sensitivity at daytime and nighttime, with and without glare.
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Affiliation(s)
- I-Jong Wang
- Department of Ophthalmology, National Taiwan University Hospital, Taipei, Taiwan.
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Dada T, Pangtey MS, Sharma N, Vajpayee RB, Jhanji V, Sethi HS. Hyeropic shift after LASIK induced diffuse lamellar keratitis. BMC Ophthalmol 2006; 6:19. [PMID: 16646976 PMCID: PMC1501054 DOI: 10.1186/1471-2415-6-19] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2005] [Accepted: 04/28/2006] [Indexed: 11/10/2022] Open
Abstract
Background Diffuse lamellar keratitis (DLK) is a relatively new syndrome that is increasingly being reported after LASIK. We have observed that a hyperopic shift may be associated with the occurrence of this diffuse lamellar keratitis. Case presentation A 26 year old man developed bilateral diffuse lamellar keratitis (DLK) following myopic LASIK. The residual refractive error was +0.5D OD and +0.25D OS at the end of the first week. The sterile infiltrates resolved over a period of 4–6 weeks on topical steroid therapy. A progressive hyperopic shift was noted in the right eye with an error +4.25Dsph/+0.25Dcyl 20 at the final follow up 6 months post surgery. Conclusion Diffuse lamellar keratitis after LASIK may be associated with a significant hyperopic shift.
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Affiliation(s)
- Tanuj Dada
- Dr Rajendran Prasad Center for Ophtahlmic Sciences, All India Institute of Medical Science, NewDelhi-110029, India
| | - Mayank S Pangtey
- Dr Rajendran Prasad Center for Ophtahlmic Sciences, All India Institute of Medical Science, NewDelhi-110029, India
| | - Namrata Sharma
- Dr Rajendran Prasad Center for Ophtahlmic Sciences, All India Institute of Medical Science, NewDelhi-110029, India
| | - Rasik B Vajpayee
- Dr Rajendran Prasad Center for Ophtahlmic Sciences, All India Institute of Medical Science, NewDelhi-110029, India
| | - Vishal Jhanji
- Dr Rajendran Prasad Center for Ophtahlmic Sciences, All India Institute of Medical Science, NewDelhi-110029, India
| | - Harinder Singh Sethi
- Dr Rajendran Prasad Center for Ophtahlmic Sciences, All India Institute of Medical Science, NewDelhi-110029, India
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Lee JE, Choi HY, Oum BS, Lee JS. A Comparative Study for Mesopic Contrast Sensitivity Between Photorefractive Keratectomy and Laser In Situ Keratomileusis. Ophthalmic Surg Lasers Imaging Retina 2006; 37:298-303. [PMID: 16898390 DOI: 10.3928/15428877-20060701-06] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
BACKGROUND AND OBJECTIVE To compare the effect on visual performance of photorefractive keratectomy (PRK) and laser in situ keratomileusis (LASIK) with mesopic contrast sensitivity. PATIENTS AND METHODS Postoperative visual performance for 40 eyes undergoing PRK and 40 eyes undergoing LASIK was compared with mesopic contrast sensitivity at 1, 3, and 6 months postoperatively. Eyes were divided into two groups (< -6.0 D and > -6.25 D). Mesopic contrast sensitivity was performed with the patient's best-corrected visual acuity of 20/20 or better under photopic conditions. RESULTS A significant decrease in mesopic contrast sensitivity from preoperative baseline was obtained at all spatial frequencies for the PRK and LASIK groups (P < .05). There was no statistically significant difference at 1 or 3 months postoperatively in both groups (P > .05). At 6 months postoperatively, LASIK significantly decreased mesopic contrast sensitivity more than PRK in myopia with a refractive error of less than -6.0 D, especially at the middle and high spatial frequencies of 6, 9, and 12 cycles per degree (P < .05). However, no statistically significant differences in mesopic contrast sensitivity between PRK and LASIK were found in myopia with a refractive error of greater than -6.25 D (P > .05). CONCLUSIONS In broad-beam excimer laser refractive surgery, PRK seemed to have a more significant effect on mesopic contrast sensitivity than LASIK for myopia with a refractive error of less than -6.0 D at 6 months postoperatively.
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Affiliation(s)
- Ji-Eun Lee
- Department of Ophthalmology, College of Medicine, Pusan National University, Korea
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Donate D, Denis P, Burillon C. Étude prospective de la sensibilité au contraste et des effets visuels après LASIK. J Fr Ophtalmol 2005; 28:1070-5. [PMID: 16395199 DOI: 10.1016/s0181-5512(05)81140-4] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
PURPOSE To evaluate changes in visual effects (contrast sensitivity, halos, and glare) following laser in situ keratomilleusis (LASIK). PATIENTS AND METHODS In this prospective study, 72 eyes had LASIK to correct myopia. Contrast sensitivity was tested preoperatively, as well as 6 and 12 months postoperatively. The spatial frequencies tested were 3, 6, 12, and 18 cycles per degree (c/d). There were two groups: group 1 for myopia between -6 D (n=30) and -7.5 D and group 2 for myopia between -7.5 D and -10 D (n=25). There were 17 cases with loss of sight. For each visit, pupil diameter, halos, and glare were measured. RESULTS Contrast sensitivity was better in group 1 than in group 2 (p<0.05) (for spatial frequencies of 3, 12, 18, c/d). In group 1, contrast sensitivity decreased 6 months postoperatively for all spatial frequencies (p<0.05); 12 months after surgery the changes were not significant. In group 2, changes were not significant. For halos and glare, pre- and postoperative percentages were not different. There was no correlation with pupil diameter. CONCLUSIONS After LASIK to correct myopia, there may be a persistent decrease in contrast sensitivity. Changes are only significant at 6 months postoperatively. Patients should be informed preoperatively of this possible decrease in functional vision.
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Affiliation(s)
- D Donate
- Service d'Ophtalmologie, Pavillon C, Hôpital Edouard Herriot, 5, place d'Arsonval, 69003 Lyon.
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Torres RM, Merayo-Lloves J, Blanco-Mezquita JT, Günther CP, Rodríguez G, Gutiérez R, Martínez-García C. Experimental Model of Laser in situ Keratomileusis in Hens. J Refract Surg 2005; 21:392-8. [PMID: 16128338 DOI: 10.3928/1081-597x-20050701-15] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
PURPOSE To develop an experimental animal model of laser in situ keratomileusis (LASIK) in hens. METHODS One hundred adult hens underwent a 60-microm corneal flap followed by -4 diopter excimer laser ablation. Surgical technique, clinical course, and pathology correlations are presented. RESULTS Sixty percent of animals had a successful LASIK outcome according to clinical observations. Pathology showed the integrity of Bowman's layer and homogeneous flap in all eyes with good clinical outcomes. Flap complications such as buttonholes (5%), free-flaps (2%), and slipped flaps (3.4%) occurred with the surgical technique. Corneal abscess (2.9%) was also present. Loss of transparency was noted in 26.4%, which correlates with epithelial ingrowth detected by light histology study. CONCLUSIONS An experimental animal model of LASIK was successfully developed in adult hens. This model could be useful in the study of wound healing and pharmacological modulation after LASIK in an animal with Bowman's layer.
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Affiliation(s)
- Rodrigo M Torres
- Instituto Universitario de Oftalmobiología Aplicada, University of Valladolid, Valladolid, Spain
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Sonigo B, Chong Sit D, Ancel JM, Auclin F, Bokobza Y, Baudouin C. Évaluation en microscopie confocale des modifications morphologiques cornéennes induites après LASIK et découpe du volet stromal par laser femtoseconde IntraLase®. J Fr Ophtalmol 2005; 28:463-72. [PMID: 15976712 DOI: 10.1016/s0181-5512(05)81082-4] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
Abstract
PURPOSE To assess stromal modifications occurring after IntraLase femtosecond laser for laser in situ keratomileusis (LASIK) using the Heidelberg retina tomograph II/Rostock cornea module. MATERIAL AND METHODS Twelve eyes from six patients were examined using the Heidelberg retina tomograph II cornea module after IntraLase femtosecond laser: ten eyes were examined at 1 week and 2 months after laser surgery, including four eyes examined at day 1, and two eyes examined at day 2. Morphological modifications of the corneal stroma, flap interface, and flap margin were evaluated at these different times and compared with the mechanical microkeratome interfaces of five patients (ten eyes), using the same technique at the same periods after the surgical intervention. RESULTS Evaluations at days 1 and 7 showed simultaneous depletion and activation of keratocytes on both sides of the interface. We also observed some brightly reflecting particles together with scattered, less bright dots, from day 7 and increasing after 2 months. Some clinically visible deposits at the level of the interface were observed at the periphery of the flap at day 1 and could represent cell-degradation products. With confocal microscopy, they appeared as homogeneous reflective deposits with a larger size than that of particles; they had decreased at month 2. The flap margin appeared microscopically as a very clear-cut edge, including epithelial cells, while those performed with a mechanical microkeratome appeared more like a poorly limited fibrotic scar. We also observed a secondary fibrotic reaction at month 2, adjacent to the still well-defined IntraLase flap edge. CONCLUSION This study showed substantial morphological similarity between the interfaces obtained with femtosecond laser and mechanical microkeratome. The discovery of brightly reflecting particles in the IntraLase interface goes against the hypothesis of the metallic origin of these deposits. The flap margin microscopically looked extremely well delimited, but seemed to provoke an adjacent secondary fibrotic reaction, both microscopically and macroscopically, greater at 2 months than after a mechanical microkeratome cut.
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Affiliation(s)
- B Sonigo
- Service d'Ophtalmologie 3, Centre Hospitalier National d'Ophtalmologie des Quinze-Vingts, Paris
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Kramer TR, Chuckpaiwong V, Dawson DG, L'Hernault N, Grossniklaus HE, Edelhauser HF. Pathologic findings in postmortem corneas after successful laser in situ keratomileusis. Cornea 2005; 24:92-102. [PMID: 15604873 DOI: 10.1097/01.ico.0000142110.37166.71] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
PURPOSE To examine the histologic and ultrastructural features of human corneas after successful laser in situ keratomileusis (LASIK). METHODS Corneas from 48 eyes of 25 postmortem patients were processed for histology and transmission electron microscopy (TEM). The 25 patients had LASIK between 3 months and 7 years prior to death. Evaluation of all 5 layers of the cornea and the LASIK flap interface region was done using routine histology, periodic acid-Schiff (PAS)-stained specimens, toluidine blue-stained thick sections, and TEM. RESULTS In patients for whom visual acuity was known, the first postoperative day uncorrected visual acuity was 20/15 to 20/30. In patients for whom clinical records were available, the postoperative corneal topography was normal and clinical examination showed a semicircular ring of haze at the wound margin of the LASIK flap. Histologically, the LASIK flap measured, on average, 142.7 microm (range, 100-200). A spectrum of abnormal histopathologic and ultrastructural findings was present in all corneas. Findings at the flap surface included elongated basal epithelial cells, epithelial hyperplasia, thickening and undulations of the epithelial basement membrane (EBM), and undulations of Bowman's layer. Findings in or adjacent to the wound included collagen lamellar disarray; activated keratocytes; quiescent keratocytes with small vacuoles; epithelial ingrowth; eosinophilic deposits; PAS-positive, electron-dense granular material interspersed with randomly ordered collagen fibrils; increased spacing between collagen fibrils; and widely spaced banded collagen. There was no observable correlation between postoperative intervals and the severity or type of pathologic change except for the accumulation the electron-dense granular material. CONCLUSIONS Permanent pathologic changes were present in all post-LASIK corneas. These changes were most prevalent in the lamellar interface wound. These changes along with other pathologic alterations in post-LASIK corneas may change the functionality of the cornea after LASIK.
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Gambato C, Ghirlando A, Moretto E, Busato F, Midena E. Mitomycin C modulation of corneal wound healing after photorefractive keratectomy in highly myopic eyes. Ophthalmology 2005; 112:208-18; discussion 219. [PMID: 15691552 DOI: 10.1016/j.ophtha.2004.07.035] [Citation(s) in RCA: 118] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2004] [Accepted: 07/28/2004] [Indexed: 11/23/2022] Open
Abstract
PURPOSE To evaluate the role of topical mitomycin C in corneal wound healing (CWH) after photorefractive keratectomy (PRK) in highly myopic eyes. DESIGN Prospective, double-masked, randomized clinical trial. PARTICIPANTS Seventy-two eyes of 36 patients affected by high (>7 diopters) myopia. METHODS In each patient, one eye was randomly assigned to PRK with intraoperative topical 0.02% mitomycin C application, and the fellow eye was treated with a placebo. Postoperatively, mitomycin C-treated eyes received artificial tears (3 times daily, tapered in 3 months), whereas the fellow eye was treated with fluorometholone sodium 2% and artificial tears (3 times daily, tapered in 3 months). MAIN OUTCOME MEASURES Uncorrected visual acuity (UCVA) and best-corrected visual acuity (BCVA), contrast sensitivity, manifest refraction, and biomicroscopy. Contrast sensitivity was determined using the Pelli-Robson chart. Corneal confocal microscopy documented CWH. RESULTS Mean follow-up was 18 months (range, 12-36). No side effects or toxic effects were documented. At 12-month follow-up examination, UCVAs (logarithm of the minimum angle of resolution) were 0.4+/-0.48 and 0.5+/-0.53 (P = .03) in mitomycin C-treated eyes and corticosteroid-treated eyes, respectively. At 1 year, corneal haze developed in 20% of corticosteroid-treated eyes, versus 0% of mitomycin C-treated eyes. At 12, 24, and 36 months, corneal confocal microscopy showed activated keratocytes and extracellular matrix significantly more evident in untreated eyes (Ps = 0.004, 0.024, and 0.046, respectively). CONCLUSION Topical intraoperative application of 0.02% mitomycin C can reduce haze formation in highly myopic eyes undergoing PRK.
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Affiliation(s)
- Catia Gambato
- Refractive Surgery Service and Antimetabolite Therapy Research Unit, Department of Ophthalmology, University of Padova, Padova, Italy
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Hammer T, Giessler S, Duncker GIW, Peschke E. Korneale Wundheilungsreaktionen nach hyperoper PRK und LASIK. Ophthalmologe 2005; 102:39-45. [PMID: 15205908 DOI: 10.1007/s00347-004-1059-4] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
Abstract
BACKGROUND The purpose of this study was to investigate the influence of different postoperative treatments on the wound healing reaction in the anterior stroma after PRK and in the interface area after LASIK. METHODS Seventy-two corneal buttons of refractively treated rabbit eyes underwent different postoperative eyedrop regimens with antibiotics and/or steroids or additional UV-B irradiation. Morphological and immunohistological investigations were performed 6 months postoperatively by light and transmission electron microscopy. RESULTS PRK eyes showed interdigitations between the epithelia and the anterior stroma. LASIK-treated eyes showed only minor changes between epithelia and stroma in the incisional region. Only a slight increase in deposits of fibrillar extracellular matrix components were detectable in the interface region. CONCLUSIONS The clinically important problem of haze after PRK is caused by the interdigitations between epithelia and anterior stroma. The delicate wound healing reactions in the interface region in LASIK eyes corresponded to the clinically visible minor changes in these corneas.
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Affiliation(s)
- T Hammer
- Augenklinik und Poliklinik, Martin-Luther-Universität, Halle-Wittenberg.
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Wirbelauer C, Pham DT. Monitoring corneal structures with slitlamp-adapted optical coherence tomography in laser in situ keratomileusis. J Cataract Refract Surg 2004; 30:1851-60. [PMID: 15342046 DOI: 10.1016/j.jcrs.2004.01.035] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 01/22/2004] [Indexed: 10/26/2022]
Abstract
PURPOSE To monitor corneal structures with slitlamp-adapted optical coherence tomography (OCT) in laser in situ keratomileusis (LASIK). SETTING Department of Ophthalmology, Vivantes Klinikum Neukölln, Berlin, Germany. METHODS In this prospective, nonrandomized, comparative clinical case series of consecutive patients who had LASIK for myopia and myopic astigmatism, the corneal structures were studied with slitlamp-adapted OCT at a wavelength of 1,310 nm. The central corneal thickness (CCT) and epithelial, flap, and residual stromal thicknesses were assessed preoperatively, immediately after surgery, on postoperative day 1, and then, on average, after 8, 35, and 160 days. RESULTS Twenty-five eyes of 13 patients were included. The attempted mean spherical equivalent correction was -6.11 diopters (D) +/- 2.16 (SD) with a mean calculated stromal ablation depth of 92 +/- 24 microm. The CCT was 516 +/- 26 microm preoperatively and 453 +/- 40 microm postoperatively (P<.001). The epithelial thickness increased from 57.0 +/- 7.7 microm preoperatively to 61.0 +/- 7.5 microm postoperatively (P =.04). Imaging of the hyperreflective interface was possible in all patients for up to 15 months. The flap and residual stromal thickness was 211 +/- 28 microm and 344 +/- 48 microm, respectively, immediately after LASIK and 164 +/- 21 microm (P<.001) and 284 +/- 32 microm (P<.001), respectively, on postoperative day 1. There were no further significant changes during the follow-up. The overall mean reproducibility was +/-4.50 microm (coefficient of variation [CV] 0.94%) for CCT, +/-4.99 microm (CV 8.57%) for epithelial thickness, +/-6.25 microm (CV 3.55%) for flap thickness, and +/-7.09 microm (CV 2.42%) for residual stromal thickness. CONCLUSION Slitlamp-adapted OCT can be used to longitudinally monitor the variable structures of the cornea, epithelium, flap, and residual stroma in LASIK.
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Neeracher B, Senn P, Schipper I. Glare sensitivity and optical side effects 1 year after photorefractive keratectomy and laser in situ keratomileusis. J Cataract Refract Surg 2004; 30:1696-701. [PMID: 15313292 DOI: 10.1016/j.jcrs.2003.12.058] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 12/04/2003] [Indexed: 10/26/2022]
Abstract
PURPOSE To compare the outcome of low-contrast visual acuity and glare sensitivity after photorefractive keratectomy (PRK) and laser in situ keratomileusis (LASIK). SETTING Department of Ophthalmology, Cantonal Hospital of Lucerne, Lucerne, Switzerland. METHODS In this prospective study, patients selected PRK or LASIK after the advantages and disadvantages of both had been described. Snellen visual acuity and disability glare were measured with the Berkeley glare test preoperatively and 1 year postoperatively. At the 1-year follow-up, haze was graded and patients had to assess their quality of vision subjectively. RESULTS One-year follow-up of 58 patients in the PRK group and 64 patients in the LASIK group was achieved. In both groups, the mean uncorrected visual acuity was 20/32 (P =.63) and the mean best corrected visual acuity, 20/20 with no statistically significant difference (P =.20). There were no preoperative or postoperative differences between the 2 groups in low-contrast visual acuity under 4 glare conditions. At 1 year, LASIK eyes had significantly lower postoperative haze scores than PRK eyes (P =.0013). The number of eyes with visually moderate and disturbing halos or disturbances in night vision did not differ considerably between the groups (P =.88). CONCLUSIONS Efficacy outcomes were generally similar in the PRK and LASIK groups. Both achieved good objective and subjective results after treatment with a second-generation excimer laser.
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Philipp W, Speicher L, Göttinger W. Histopathologische und immunhistochemische Befunde nach LASIK bei Hyperopie. SPEKTRUM DER AUGENHEILKUNDE 2004. [DOI: 10.1007/bf03163154] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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Seo KY, Lee JH, Kim MJ, Park JW, Chung ES, Lee YS, Kim EK. Effect of Suturing on Iatrogenic Keratectasia After Laser in situ Keratomileusis. J Refract Surg 2004; 20:40-5. [PMID: 14763470 DOI: 10.3928/1081-597x-20040101-08] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
PURPOSE To evaluate the influence of corneal suturing on the clinical course of iatrogenic keratectasia after laser in situ keratomileusis (LASIK), in order to improve quality of vision and to avoid progressive deterioration of visual acuity. METHODS Three patients (four eyes) who had a perforation during LASIK or became keratectatic after LASIK received corneal suturing with 10-0 nylon immediately or up to 11 days after LASIK. Sutures were left in place for 1 to 4 months. Patients were followed for 20 to 23 months after suturing. RESULTS All eyes had a significant improvement in uncorrected and best spectacle-corrected visual acuity after suturing. The improvements in visual acuity for all patients remained unchanged after suture removal. In patient 1, keratectatic changes were not detected in the sutured eye although they were detected in the contralateral unsutured eye. In patient 2, both eyes were sutured, one immediately and the other 11 days after LASIK; no keratectatic changes were noted in either eye. Slight progression of corneal protrusion was observed in patient 3, who had corneal suturing after development of prominent keratectasia 2 weeks after LASIK. This eye showed stable but moderate keratectatic change 9 months after suture removal. CONCLUSIONS Flap suturing in patients during the course of keratectasia after LASIK improved both aided and unaided visual acuity. Prompt suturing seemed to provide a means of preventive management for iatrogenic keratectasia in anticipation of keratoplasty.
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Affiliation(s)
- Kyoung Yul Seo
- Department of Ophthalmology, Yonsei Institute of Vision Research, Yonsei University College of Medicine, Seoul, Korea
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Abstract
PURPOSE To report clinical and confocal microscopy characteristics of haze-like opacities in corneas after laser in situ keratomileusis (LASIK). SETTING Department of Ophthalmology, Johann Wolfgang Goethe-University, Frankfurt am Main, Germany. METHODS Eighteen eyes of 11 patients with clinically apparent corneal clouding were examined by slitlamp and confocal microscopy (Confoscan P4, Tomey) 1 to 9 months after primary LASIK or LASIK retreatment. RESULTS Postoperative slitlamp examination showed faint, white, snowflake-like clouding at the interface level in all patients. One patient had folds and rather diffuse haze-like opacities. Confocal microscopy revealed highly reflective structures in the flap stroma and at the interface level in all patients, probably due to numerous activated keratocytes and their processes. The confocal microscopy appearance was similar to that of photorefractive keratectomy haze. CONCLUSION Focal wound-healing reactions in the central flap stroma and interface resulting in significant keratocyte activation could be observed after LASIK.
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Affiliation(s)
- Jens Bühren
- Department of Ophthalmology, Johann Wolfgang Goethe-University, Frankfurt am Main, Germany
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Shoji N, Hayashi E, Shimizu K, Uga S, Sugita J. Central Corneal Haze Increased by Radial Keratotomy Following Photorefractive Keratectomy. J Refract Surg 2003; 19:560-5. [PMID: 14518745 DOI: 10.3928/1081-597x-20030901-11] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
PURPOSE To report a case of central corneal haze induced by minimally invasive radial keratotomy (mini-RK) after photorefractive keratectomy (PRK) and subsequent deep lamellar keratoplasty. METHODS We report a case (one eye of one patient) of central corneal haze that worsened after mini-RK was performed 2 years following PRK. Four years later, a second PRK was done, myopic regression was subsequently observed, and corneal haze persisted. Deep lamellar keratoplasty was performed and a corneal graft was taken, which was examined by light and electron microscopy. RESULTS In the ablated area, irregularity of the basal membrane and hypertrophy of the corneal epithelium were observed. In the stromal layer, collagen fibers showed disorder in their disposition. Aggregated activated keratocytes were observed. An epithelial plug filling the gap of the RK incision persisted for 6 years after the mini-RK. The RK incision was easily divided when deep lamellar keratoplasty was performed and the patient obtained a stable visual outcome. CONCLUSIONS It is possible that mini-RK enhancement after PRK induces central corneal haze and reduces corneal integrity. Deep lamellar keratoplasty for refractory corneal haze after refractive surgery was useful in this eye.
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Affiliation(s)
- Nobuyuki Shoji
- Department of Orthoptics and Visual Science, Kitasato University School of Allied Health Science, Kanagawa, Japan.
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Nieto A, Casas J, Rahhal SM, Alonso L, Martínez-Soriano F, Sanchis-Gimeno JA. NGF and TGF-beta mRNA expression during pregnancy in a rat corneal wound healing model. Clin Exp Optom 2003; 86:239-43. [PMID: 12859243 DOI: 10.1111/j.1444-0938.2003.tb03112.x] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2002] [Revised: 02/10/2003] [Accepted: 02/14/2003] [Indexed: 11/29/2022] Open
Abstract
BACKGROUND Growth factors seem to play a major role in corneal wound healing and TGF-beta seems to be associated with abnormal healing after corneal surgical procedures. Few studies have analysed the role of NGF and TGF-beta on corneal wound healing during pregnancy. The aim of the present study was to create an animal model to evaluate the expression of NGF and TGF-betas during corneal wound healing in two groups: control and pregnant rats. METHODS Corneal mRNA for NGF and the three isoforms of TGF-beta were analysed by RT-PCR, in a time-course experiment on different days after epithelial wounding (2, 7, 14 days) in pregnant and control groups RESULTS The results show high corneal mRNA expression for NGF and TGF-beta1 without any variation throughout the healing process or pregnancy evolution. However, we detected a different expression of corneal mRNAs for TGF-beta2 and TGF-beta3 in the control group. This data was not detected in the pregnant group. DISCUSSION Our results suggested that pregnancy could have a relevant role on TGF-beta2 and TGF-beta3 mRNA expression during the corneal wound healing process. Additional research should be performed to corroborate these findings.
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Affiliation(s)
- A Nieto
- Department of Anatomy and Human Embryology, Faculty of Medicine, University of Valencia, Valencia, Spain
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Møller-Pedersen T. On the structural origin of refractive instability and corneal haze after excimer laser keratectomy for myopia. ACTA ACUST UNITED AC 2003. [DOI: 10.1034/j.1600-0420.81.s237.1.x] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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Holzer MP, Vargas LG, Sandoval HP, Vroman DT, Kasper TJ, Brown SJ, Apple DJ, Solomon KD. Corneal flap complications in refractive surgery: Part 1: development of an experimental animal model. J Cataract Refract Surg 2003; 29:795-802. [PMID: 12686252 DOI: 10.1016/s0886-3350(03)00096-8] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
PURPOSE To report the outcome, learning curve, and complication rates of an experimental animal model for corneal flaps in refractive surgery. SETTING Magill Research Center for Vision Correction, Storm Eye Institute, Charleston, South Carolina, USA. METHODS Corneal flaps with a nasal or a temporal hinge were created in 190 eyes of 95 Dutch Belted rabbits using the Automated Corneal Shaper microkeratome (Bausch & Lomb Surgical). Diffuse lamellar keratitis (DLK) was induced by inoculating the corneal interfaces with 1 of 7 substances. Postoperatively, the eyes were examined with a slitlamp. Special emphasis was placed on corneal flap complications and the relationship between slipped flaps and hinge position and/or inoculation agent. RESULTS A good corneal flap was achieved in 174 eyes (92%). The eyes with a nasal hinge had a lower incidence of slipped flaps (14%) than eyes with a temporal hinge (37%) (P =.02). CONCLUSION With the animal model described, corneal flaps were created in a precise and reproducible way in more than 90% of eyes. Nasal hinged flaps showed less postoperative displacements than temporal hinged flaps and are adequate for further study.
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Affiliation(s)
- Mike P Holzer
- Magill Research Center for Vision Correction, Storm Eye Institute, Medical University of South Carolina, Charleston 29425, USA
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Philipp WE, Speicher L, Göttinger W. Histological and immunohistochemical findings after laser in situ keratomileusis in human corneas. J Cataract Refract Surg 2003; 29:808-20. [PMID: 12686254 DOI: 10.1016/s0886-3350(02)01611-5] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
PURPOSE To describe histopathological and immunohistochemical findings in human corneas after myopic laser in situ keratomileusis (LASIK) followed by iatrogenic keratectasia and after hyperopic LASIK. SETTING Department of Ophthalmology, University of Innsbruck, Innsbruck, Austria. METHODS Clinical, histological, and immunohistochemical investigations were performed of 1 human cornea with iatrogenic keratectasia following myopic LASIK and 1 human cornea with irregular astigmatism and central scar formation after hyperopic LASIK. Corneal buttons were obtained during penetrating keratoplasty in both patients. RESULTS Histopathological examination showed thinning of the central stroma with a posterior residual thickness of 190 microm in the patient with iatrogenic keratectasia after myopic LASIK and significant midperipheral thinning in the patient who had hyperopic LASIK. However, this characteristic ablation profile of the stroma after hyperopic LASIK was partially mitigated and compensated by the epithelium, which was significantly thinned in the center and markedly thickened in the midperiphery. Traces of wound healing with minimal scar tissue were present at the flap margin after myopic and hyperopic LASIK. In a few sections of the cornea with keratectasia after myopia LASIK, only a few collagen lamellae were visible crossing between the posterior residual stroma and the superficial flap. Immunohistochemical examination revealed minimally increased staining of dermatan sulfate proteoglycan within the stroma adjacent to the interface of the microkeratome incision. Increased staining of hepatocyte growth factor was found on keratocytes/fibroblasts at the flap margin in both corneas. CONCLUSIONS The wound-healing response is generally poor after LASIK, which may result in significant weakening of the tensile strength of the cornea after myopic LASIK, probably due to biomechanically ineffective superficial lamella. After LASIK in patients with high hyperopia, compensatory epithelial thickening in the annular midperipheral ablation zone might be partly responsible for regression.
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Goodman RL, Johnson DA, Dillon H, Edelhauser HF, Waller SG. Laser in situ keratomileusis flap stability during simulated aircraft ejection in a rabbit model. Cornea 2003; 22:142-5. [PMID: 12605050 DOI: 10.1097/00003226-200303000-00013] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
PURPOSE To determine the stability of the laser in situ keratomileusis (LASIK) flap in a rabbit model when subjected to vertical acceleration at nine times the force of gravity (+9 Gz) in an aircraft cockpit ejection simulator. METHODS Thirty-six eyes from 25 New Zealand white rabbits underwent LASIK flap creation without laser photoablation. One month after surgery, the rabbits were sedated and harnessed in a cockpit ejection seat simulator used to train United States Air Force pilots. They then underwent a controlled rapid-sequence ejection at +9 Gz. Subsequently, the rabbits were euthanized and the corneas harvested for microscopic examination. Refractive measurements and corneal examination were made before LASIK flap creation and prior to and after the +9 Gz ejections. Determination of LASIK flap dislocation was based on clinical observation of flap slippage or a significant shift in pre-ejection to postejection cylinder axis. RESULTS The average preoperative refraction of the rabbit eye was +1.83 D + 3.25 D x 086 degrees. The average change from pre-ejection to postejection was 0.04 D sphere, 0.02 D cylinder, 6.8 axis degrees, and 0.04 D spherical equivalent. The pre-ejection to postejection measurements were not statistically significantly different by a paired test. Laser in situ keratomileusis flap dislocation or ejection-induced corneal folds or striae were not clinically observed. Histologic examination revealed well-healed LASIK flaps but no reactive keratocytes at the central stromal-stromal interface. CONCLUSIONS Healed LASIK flaps as created in this rabbit model without laser ablation are stable when subjected to a rapid vertical ejection at nine times the force of gravity.
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Affiliation(s)
- Randall L Goodman
- Ophthalmology service, Mike O'Callaghan Federal Hospital, 99MDG/SGOSE, Nellis AFB, NV 89191, USA.
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Schulz D, Iliev ME, Frueh BE, Goldblum D. In vivo pachymetry in normal eyes of rats, mice and rabbits with the optical low coherence reflectometer. Vision Res 2003; 43:723-8. [PMID: 12604109 DOI: 10.1016/s0042-6989(03)00005-1] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
The aim of this study was to determine the central corneal thickness (CCT) in living rats, mice and rabbits using a non-contact, high-speed optical low coherence reflectometer (OLCR) mounted on a regular slit lamp. Both eyes of eight male Wistar rats, eight male balb-c mice and eight male Japanese rabbits were measured. Each eye was measured twice (one measurement consists of 20 scans), the average calculated. Additionally, CCT was measured in rabbits using an ultrasound pachymeter. The mean CCT was: RATS: 159.08 microm (SD+/-14.99 microm), MICE: 106.0 microm (SD+/-3.45 microm) and RABBITS: 356.11 microm (SD+/-14.34 microm). With the use of OLCR we were able to accurately measure the CCT of rats, mice and rabbits in vivo. This technique may prove useful in further refractive, pharmacological and glaucoma studies.
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Affiliation(s)
- Dominic Schulz
- Department of Ophthalmology, University of Bern, Inselspital, CH-3010, Bern, Switzerland
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Katsanevaki VJ, Ginis HS, Naoumidi II, Pallikaris IG. The PALM Technique: histological findings of masked phototherapeutic keratectomy on rabbit corneas. BMC Ophthalmol 2003; 3:4. [PMID: 12597779 PMCID: PMC151685 DOI: 10.1186/1471-2415-3-4] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2002] [Accepted: 02/19/2003] [Indexed: 11/29/2022] Open
Abstract
BACKGROUND To compare the corneal healing response between conventional and phototherapeutic keratectomy through a masking agent, in rabbit corneas. METHODS 24 adult rabbits underwent phototherapeutic keratectomy. Animals were divided in two groups: 12 received photoablation through a masking agent (PALM gel) and the remaining 12 received conventional phototherapeutic keratectomy of equal depth and served as control. Light and transmission electron microscopy was performed in specimens of both groups obtained: immediately after, four hours, one week, one, three and six months after treatment. RESULTS Reepitheliazation was complete within five days in all eyes. Light and transmission electron microscopy did not reveal any differences of the healing process in the experimental eyes compared to the controls. CONCLUSION Photoablation through the PALM technique did not result any evident alterations of the reepithelisation and stromal healing process.
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Affiliation(s)
- Vikentia J Katsanevaki
- University of Crete, Medical School, Vardinoyannion Eye Institute of Crete, Heraklion, Crete, Greece
- University Hospital of Crete, Department of Ophthalmology, Heraklion Greece
| | - Harilaos S Ginis
- University of Crete, Medical School, Vardinoyannion Eye Institute of Crete, Heraklion, Crete, Greece
| | - Irini I Naoumidi
- University of Crete, Medical School, Vardinoyannion Eye Institute of Crete, Heraklion, Crete, Greece
| | - Ioannis G Pallikaris
- University of Crete, Medical School, Vardinoyannion Eye Institute of Crete, Heraklion, Crete, Greece
- University Hospital of Crete, Department of Ophthalmology, Heraklion Greece
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Chan JWW, Edwards MH, Woo GC, Woo VCP. Contrast sensitivity after laser in situ keratomileusis. one-year follow-up. J Cataract Refract Surg 2002; 28:1774-9. [PMID: 12388027 DOI: 10.1016/s0886-3350(02)01499-2] [Citation(s) in RCA: 62] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
PURPOSE To determine whether contrast sensitivity measurement, a more sensitive test of visual function than visual acuity, better characterizes visual outcomes after laser in situ keratomileusis (LASIK). SETTING Hong Kong Laser Eye Centre, Hong Kong, China. METHODS Contrast sensitivity was monitored in 41 LASIK patients for 1 year. Seven spatial frequencies (0.3, 0.8, 1.5, 3.4, 6.9, 10.3, and 20.5 cpd) were tested with 15 sequences per spatial frequency, and a staircase technique was used for target presentation. RESULTS There was a general depression in the contrast sensitivity function after LASIK; 1.5 cpd and 3.4 cpd were the most affected frequencies. Recovery took at least 6 months. The reduction in contrast sensitivity was greater for higher amounts of myopia. CONCLUSION The post-LASIK nonpermanent depression in contrast sensitivity was probably due to optical factors.
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Affiliation(s)
- Jay W W Chan
- Centre for Myopia Research, Department of Optometry and Radiography, The Hong Kong Polytechnic University , Hong Kong, China
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Spadea L, Palmieri G, Mosca L, Fasciani R, Balestrazzi E. Iatrogenic Keratectasia Following Laser in situ Keratomileusis. J Refract Surg 2002; 18:475-80. [PMID: 12160161 DOI: 10.3928/1081-597x-20020701-12] [Citation(s) in RCA: 40] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
PURPOSE To evaluate keratectasia after laser in situ keratomileusis (LASIK) for high myopia. METHODS A 49-year-old male patient with myopia of -23.50 D in both eyes underwent LASIK with a Summit Technology Apex Plus excimer laser. A Moria manually-guided MDSC microkeratome was used. Preoperative corneal topography in both eyes did not reveal underlying or fruste form of keratoconus. Four months after LASIK, a progressive keratectasia occurred in right eye and after 12 months, in left eye. Corneal transplantation was performed in both eyes. RESULTS Histological and ultrastructural examinations were performed on one corneal button. The analysis showed regular stromal morphology and cellularity, with no sign of inflammation. The morphometric analysis showed an overall thickness of 334 microm, with a flap of 262 microm and a stromal residual bed of 72 microm, in the center of the button. CONCLUSION A LASIK corneal flap made with a planned 120-microm plate turned out histologically to be approximately 260 microm thick, in an eye with a refractive correction of -23.50 D. The excessive flap thickness and excessive ablation produced progressive keratectasia requiring a penetrating keratoplasty.
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Sen HN, Uusitalo R, Laatikainen L. Subclinical inflammation after laser in situ keratomileusis in corneal grafts. J Cataract Refract Surg 2002; 28:782-7. [PMID: 11978455 DOI: 10.1016/s0886-3350(02)01239-7] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
PURPOSE To evaluate postoperative inflammatory reaction in the eye after laser in situ keratomileusis (LASIK) in corneal grafts. SETTING Department of Ophthalmology, Helsinki University Central Hospital, Helsinki, Finland. METHODS Ten eyes of 9 patients with penetrating keratoplasty (PKP) and significant postoperative refractive errors and astigmatism had LASIK 22 months or more after the PKP. All patients were treated with the VISX Star excimer laser and the Bausch & Lomb Hansatome microkeratome. Preoperative and early postoperative inflammation was evaluated by quantifying the aqueous flare intensity with a laser flare photometer (Kowa FM-500). A full ophthalmic assessment was also performed before LASIK and up to 6 months postoperatively. RESULTS The inflammatory response was mild and limited to the first postoperative hour. The mean anterior chamber flare increased from 6.0 photons/millisecond (ph/ms) preoperatively to 14.0 ph/ms at 1 hour and then decreased to 6.7 ph/ms (hour 3), 6.8 ph/ms (day 1), and 8.2 ph/ms (day 7). The mean spherical equivalent (SE) refraction decreased from -3.81 diopters (D) (range -9.63 to -0.25 D) to -0.46 D (range -1.13 to +0.38 D), and the mean preoperative astigmatism decreased from 3.0 D (range 6.5 to 0.5 D) to 0.7 D (range 0.0 to 2.0 D). At the last examination, 9 eyes were within +/-1.0 D (6 within +/-0.5 D) and all were within +/-1.5 D of the intended SE refraction. Three eyes achieved full cylinder correction, and 7 were within +/-1.0 D of the intended correction. Eight eyes had a best corrected visual acuity of 20/40 or better (unchanged or gain of 1 to 4 lines [6], loss of 1 line [1], and loss of 3 lines [1]), and 8 had an uncorrected visual acuity of 20/50 or better. CONCLUSIONS Uneventful LASIK induced subtle, short-lasting anterior chamber flare when measured by the laser flare meter. In corneal grafts, LASIK appeared to be a safe and effective procedure for residual refractive errors.
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Affiliation(s)
- Hatice Nida Sen
- Department of Ophthalmology, Helsinki University Central Hospital, Helsinki, Finland.
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Berlau J, Becker HH, Stave J, Oriwol C, Guthoff RF. Depth and age-dependent distribution of keratocytes in healthy human corneas: a study using scanning-slit confocal microscopy in vivo. J Cataract Refract Surg 2002; 28:611-6. [PMID: 11955900 DOI: 10.1016/s0886-3350(01)01227-5] [Citation(s) in RCA: 63] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
PURPOSE To document keratocyte distribution and changes with age in the cellular network of the human cornea in vivo. SETTING Department of Ophthalmology, University of Rostock, Rostock, Germany. METHODS Forty-nine eyes of 31 healthy subjects of various ages were examined with a modified Microphthal scanning-slit confocal microscope (SSCM) (Hund) to document keratocyte distribution in the intact living cornea. Optical sections made by confocal microscopy were recorded on videotape, and the keratocyte density was determined for the total volume of the cornea and for the stromal sublayers. RESULTS The highest cell density was in the anterior stroma of the cornea immediately posterior to Bowman's membrane (24 320 cells/mm(3) +/- 6740 [SD]), the lowest in the central area (11,610 +/- 4290 cells/mm(3)), and an intermediate density in the posterior stroma immediately adjacent to Descemet's membrane (18,850 +/- 4610 cells/mm(3)). The differences were statistically significant (P <.005). The keratocyte density was significantly lower in the anterior and posterior regions in the group older than 50 years: Cell density at 4% depth was 20,960 +/- 8200 cells/mm(3) and at 96%, 15 520 +/- 4290 cells/mm(3) (P <.05). CONCLUSIONS In healthy living corneas, the keratocyte density was high in the areas adjacent to Bowman's and Descemet's membranes and was lower in patients older than 50 years than in those younger than 50 years. Further studies are needed to document the rate of change with age and to better understand the role and capacity of aging keratocytes in regenerative processes following corneal diseases or surgical procedures.
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Affiliation(s)
- Jens Berlau
- Department of Ophthalmology, University of Rostock, Rostock, Germany
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Mitooka K, Ramirez M, Maguire LJ, Erie JC, Patel SV, McLaren JW, Hodge DO, Bourne WM. Keratocyte density of central human cornea after laser in situ keratomileusis. Am J Ophthalmol 2002; 133:307-14. [PMID: 11860965 DOI: 10.1016/s0002-9394(01)01421-0] [Citation(s) in RCA: 64] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
Abstract
PURPOSE To determine changes in keratocyte density in the first year after laser in situ keratomileusis (LASIK). DESIGN Prospective interventional cohort study. METHODS Seventeen eyes of 11 patients received LASIK with a planned 180-microm flap to correct refractive errors between -2.0 diopters and -11.0 diopters. Images of the full-thickness cornea were obtained by using confocal microscopy in vivo before LASIK and at 1 week, 1, 3, 6, and 12 months after LASIK. Bright objects (that resembled keratocytes) in images without motion blur were manually counted by one observer. Cell densities were determined in anterior and posterior halves of the stromal flap, anterior and posterior halves of the layer 100 microm-thick immediately deep to the ablation (retroablation layer), and in the posterior third of the stroma. The region of stroma that was ablated (as measured 1 month after LASIK) was omitted from the preoperative analysis. RESULTS Keratocyte density in the anterior flap was 28,978 +/- 5849 cells/mm(3) (mean +/- SD) pre-LASIK, and was decreased at all postoperative examinations, but the difference was not significant until 12 months after LASIK (22% decrease). Keratocyte densities in the posterior flap were 20,397 +/- 4215 cells/mm(3) pre-LASIK and were decreased by 20%-40% at all postoperative examinations 1 week to 1 year after LASIK. Keratocyte densities in the anterior half of the retroablation layer were 16,605 +/- 3595 cells/mm(3) pre-LASIK and decreased by 16%-30% between 3 and 12 months after LASIK. Keratocyte densities in the posterior half of the retroablation layer and posterior stroma did not change. CONCLUSIONS Keratocyte densities in the posterior flap and anterior retroablation layer (regions adjacent to the lamellar cut) decrease at 1 week and 3 months, respectively, after LASIK and remain decreased in these regions at 12 months after LASIK. In the anterior flap, keratocyte density decreases 1 year after LASIK. The long-term effects of these cellular deficits, if any, require further study.
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Affiliation(s)
- Katsuya Mitooka
- Department of Ophthalmology, Mayo Clinic, Rochester, Minnesota 55905, USA
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Alonso-Muñoz L, Lleó-Pérez A, Rahhal MS, Sanchis-Gimeno JA. Assessment of applanation tonometry after hyperopic laser in situ keratomileusis. Cornea 2002; 21:156-60. [PMID: 11862085 DOI: 10.1097/00003226-200203000-00005] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
PURPOSE To determine the reliability and identify pitfalls in intraocular pressure measurement by Goldmann applanation tonometry after hyperopic laser in situ keratomileusis (LASIK). METHODS Prospective non-masked case series at University of Valencia, Faculty of Medicine and Rahhal Ophthalmology Clinic, Valencia, Spain. One hundred three patients (103 eyes) treated with hyperopic LASIK were evaluated. The main treatment was hyperopic LASIK using a microkeratome Chiron Hansatome (Chiron Vision Corp, Claremont, CA) and the excimer laser Chiron Technolas 217-C LASIK (Chiron Technolas GmbH, Dornack; Germany). Central Goldmann applanation tonometric readings before surgery and 1, 3, and 6 months after surgery were analyzed. RESULTS After hyperopic LASIK, a significant decrease in intraocular pressure was observed in the postoperative controls. In the low hyperopia patients (range: 1.00-3.00 D) a decrease of 2.43 mmHg was observed at the 6-month follow-up (p < 0.001). In the moderate hyperopia group (range: 3.25-6.00 D) a decrease of 2.05 mmHg was observed at the 6-month follow-up (p < 0.001). There were no significant differences between low and moderate hyperopia (p = 0.812). There was no statistically significant correlation between the magnitude of decrease in tonometry and gender, age, treated spherical equivalent, pachymetry, and anterior chamber depth (ACD). CONCLUSIONS This clinical study displays that postoperative tonometry after hyperopic LASIK was significantly lower than the preoperative, hence modifying the reliability of Goldmann tonometry, and causing an intraocular pressure underestimation. A correcting factor should be applied when using applanation tonometry to measure postoperative intraocular pressure in patients who have undergone hyperopic LASIK.
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Nagy ZZ, Tóth J, Nagymihály A, Süveges I. The role of ultraviolet-B in corneal healing following excimer laser in situ keratomileusis. Pathol Oncol Res 2002; 8:41-6. [PMID: 11994762 DOI: 10.1007/bf03033700] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
Corneal photoablation with the 193 nm argon fluoride excimer laser during photorefractive keratectomy (PRK) in high diopter range is frequently associated with subepithelial haze and consequent refractive regression due to avascular corneal wound healing. The wound healing response can be augmented by Ultraviolet-B (UV-B) exposure originating from sun or solarium. Clinically Laser in situ Keratomileusis (LASIK) even in high diopter range is associated with less subepithelial haze and regression than PRK. In an animal model, the morphologic changes of the rabbit cornea were evaluated following LASIK and secondary UV-B exposure. Light microscpic changes were found to be insignificant. Transmission electron microscopy (TEM) normal epithelium, epithelial adhesion structures and normal anterior stroma showed in the LASIK treated UV-B irradiated rabbit eyes. Around the peripheral LASIK cut, migrating keratocytes with pseudopodia were observed. Under the flap (160 microm depth) the overall stromal collagen structure was normal, some activated keratocytes and mild extracellular matrix formation within and around keratocytes were noted. Within activated keratocytes TEM showed prominent rough endoplasmic reticulum, Golgi apparatus, mitochondria and extracellular vacuoles, which showed resolution with time. These changes were much milder than in PRK treated-UV-B irradiated eyes. Secondary UV-B caused no long-term disturbance in corneal transparency in LASIK and UV-B treated rabbit eyes.
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Affiliation(s)
- Zoltán Zsolt Nagy
- Semmelweis University, 1(st) Department of Ophthalmology Töm u. 25-29, Budapest, 1083, Hungary
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Pisella PJ, Auzerie O, Bokobza Y, Debbasch C, Baudouin C. Evaluation of corneal stromal changes in vivo after laser in situ keratomileusis with confocal microscopy. Ophthalmology 2001; 108:1744-50. [PMID: 11581044 DOI: 10.1016/s0161-6420(01)00771-0] [Citation(s) in RCA: 87] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
Abstract
PURPOSE To assess by in vivo confocal microscopy the modifications of the corneal stroma after laser in situ keratomileusis (LASIK) for myopia. DESIGN Nonrandomized comparative (self-controlled) trial. PARTICIPANTS Sixteen eyes of 13 patients were examined before surgery and at days 8, 30, and 90, and 9 eyes were examined at 6 months postoperatively using an in vivo confocal microscope. TESTING/INTERVENTION: Stromal morphologic changes, keratocyte density, flap thickness, and subclinical haze were evaluated and compared at different time points. LASIK was performed with a Flapmaker microkeratome (Solan Ophthalmic products, Jacksonville, FL) and a Lasersight LSX excimer laser (LaserSight Technologies Inc., Winter Park, FL). MAIN OUTCOME MEASURE Confocal microscopy results. RESULTS Microfolds at the Bowman's layer were found in most eyes, as well as variable reflectivity particles (pa) located at the interface level in all eyes examined postoperatively. The density of these particles significantly decreased with time with, respectively, 504 +/- 101 pa/mm2 at day 8 and 380 +/- 111 pa/mm2 at day 30 (P = 0.003), 332 +/- 100 pa/mm2 at month 3 and 312 +/- 40 pa/mm2 at month 6. The mean flap and the activated-cells area thicknesses were, respectively, 102 +/- 26 microm and 61 +/- 19 microm and showed significant negative correlation (P < 0.0001). The intensity of the added peak (47.3 microm 8.6%), corresponding to the subclinical haze, realized by Z-scan measure, was also negatively correlated with flap thickness (P = 0.01). Keratocyte (k) density quantified in the posterior stroma significantly increased from day 0 (480 +/- 67 k/mm2) to day 8 (701 +/- 41 k/mm2, P < 0.0001 compared with day 0) and day 30 (917 +/- 143 k/mm2, P = 0.0006, compared with day 0) but significantly decreased at 3 months postoperatively (597 +/- 56 k/mm2, P < 0.0001 compared with day 30) to reach the initial level at month 6 (502 +/- 41 k/mm2, nonsignificant compared with day 0). There was no correlation between preoperative or postoperative spherical equivalent and the density of particles, keratocytes, and the haze intensity. CONCLUSIONS This study confirms the presence of microfolds and particles at the interface level, as well as subclinical impairment. Evaluation of keratocyte density constitutes a major contribution of confocal microscopy toward an understanding of the keratocyte response to corneal wound healing after corneal refractive surgery. Moreover, flap thickness seems to be involved in the postoperative cellular activation with a higher response when thin.
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Affiliation(s)
- P J Pisella
- Department of Ophthalmology, Ambroise Paré Hôpital, AP-HP, Quinze-Vingts National Hospital University Paris-V, France
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El-Harazi SM, Chuang AZ, Yee RW. Assessment of anterior chamber flare and cells after laser in situ keratomileusis. J Cataract Refract Surg 2001; 27:693-6. [PMID: 11377897 DOI: 10.1016/s0886-3350(01)00798-2] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
PURPOSE To determine the presence of anterior chamber flare and cells after laser in situ keratomileusis (LASIK) for the correction of myopia. SETTING Hermann Eye Center and the University of Texas Medical School, Department of Ophthalmology and Visual Science, Houston, Texas, USA. METHODS Forty-three eyes of 23 consecutive patients ranging in age from 24 to 62 years had LASIK for myopia. All surgeries were performed by a single surgeon using a VISX Star laser and the same technique. Patients received no preoperative antiinflammatory medications. Postoperatively, all patients were instructed to use 1 drop of ofloxacin (Ocuflox) and 1 drop of fluorometholone 0.1% (FML) in the operated eye 4 times daily while awake for 7 days. At baseline and postoperative days 1, 7, and 28, anterior chamber flare was measured and cells were counted using a Kowa laser flare meter (FM-500) and laser cell counter (LC-500), respectively. RESULTS Flare and cells increased significantly on day 1 (P <.0001 for both flare and cells) and returned to preoperative levels by day 7. No statistically significant correlation was detected between the amount of inflammation and the number of laser pulses (P =.2922) or the ablation time (P =.8383). CONCLUSIONS A significant increase in anterior chamber inflammation occurred during the first 24 hours after LASIK. Inflammation levels then subsided to preoperative levels by day 7 with steroid use. Anterior chamber inflammation did not appear to correlate with the duration of the ablation or the number of laser pulses.
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Affiliation(s)
- S M El-Harazi
- Department of Ophthalmology and Visual Science, The University of Texas Health Science Center, Houston, Texas, USA
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Frueh BE, Eggli P, Böhnke M. Morphology of the Stromal Surface and Endothelium Using Two Different Microkeratomes. J Refract Surg 2001; 17:428-32. [PMID: 11472000 DOI: 10.3928/1081-597x-20010701-04] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
PURPOSE To compare stromal surface and endothelial morphology after keratectomies and after laser in situ keratomileusis (LASIK), using two different microkeratomes. METHODS Keratectomies (160-microm and 400-microm) were performed on 82 enucleated porcine eyes using the Chiron Automated Corneal Shaper (52 eyes) and the Microtech Turbokeratome (30 eyes). LASIK procedures of -9.00 D, -27.00 D, and -36.00 D were performed with a Schwind excimer laser. The corneas were immediately fixed in glutaraldehyde or stained with alizarin red and trypan. Scanning electron microscopy was then performed. RESULTS All keratectomies performed with the Chiron microkeratome displayed a relatively smooth surface. The quality of the keratectomies with the manually advanced Microtech microkeratome was variable, with a high incidence (4 of 9) of incomplete cuts and irregular surfaces. In the eyes in which the stromal laser ablation was performed, a thin layer of condensed stroma (pseudomembrane formation) was seen. Vital staining did not indicate endothelial damage. CONCLUSIONS The surface morphology was unacceptable for one of the microkeratomes tested. Keratectomies of 160 to 400 microm and LASIK up to -36.00 D did not acutely alter endothelial morphology in porcine eyes.
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Affiliation(s)
- B E Frueh
- Department of Ophthalmology, University of Bern, Switzerland
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Peters NT, Iskander NG, Anderson Penno EE, Woods DE, Moore RA, Gimbel HV. Diffuse lamellar keratitis: isolation of endotoxin and demonstration of the inflammatory potential in a rabbit laser in situ keratomileusis model. J Cataract Refract Surg 2001; 27:917-23. [PMID: 11408141 DOI: 10.1016/s0886-3350(00)00779-3] [Citation(s) in RCA: 54] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
Abstract
PURPOSE To systematically examine sources of endotoxin contamination in eye centers as a potential cause of diffuse lamellar keratitis (DLK) and to demonstrate the inflammatory potential of endotoxin in a rabbit model of laser in situ keratomileusis (LASIK) surgery. SETTING University of Calgary, Calgary, Alberta, Canada. METHODS In this prospective study, all water sources that routinely come in contact with LASIK instruments, including sterilizer reservoirs, eyedrops, microkeratome blades, and cleaning solutions, were examined for endotoxins at 5 eye centers. Bacterial cultures were performed on water samples from 5 sterilizer reservoirs. A LASIK flap was created in 8 rabbit eyes using an Automated Corneal Shaper microkeratome (Bausch & Lomb). The flaps were reflected, and a dose of endotoxin at various concentrations was placed on the interface. After 1 minute, the flap was irrigated and repositioned. The rabbit eyes were examined daily with a slitlamp biomicroscope for 3 days for the development of DLK, which was classified on a scale from grade 1 to 4 (mild to severe). The rabbits were killed at the conclusion of the study, and the interfaces were stained to rule out infectious etiologies. RESULTS Endotoxin was detected in significant concentrations in tap water, filtered and distilled water, instrument washbasins, and sterilizer reservoirs at all 5 centers. The cultures of the water samples taken from the sterilizer reservoirs ranged from no growth to the presence of >100 colony-forming units of Flavobacterium and Pseudomonas aeruginosa. Endotoxins caused DLK-like interface inflammation in all eyes tested. Examination of stained scrapings showed no microorganisms in the interface of the rabbit eyes. CONCLUSION Endotoxin contamination was detected in water sources that routinely come in contact with LASIK instruments. Endotoxins were capable of inducing interface inflammation in a rabbit model and may therefore be a significant factor in epidemic DLK.
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Affiliation(s)
- N T Peters
- Gimbel Eye Centre, Calgary, Alberta, Canada.
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