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Koosha N, Riazi MS, Janfaza P, Mohammadbeigy I, Rahimi A, Khoshali M, Pourazizi M, Peyman A. Laser vision correction after radial keratotomy: systematic review and meta-analysis. J Cataract Refract Surg 2024; 50:767-776. [PMID: 38353281 DOI: 10.1097/j.jcrs.0000000000001426] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2023] [Accepted: 02/09/2024] [Indexed: 06/25/2024]
Abstract
Laser vision correction for residual refractive errors in patients with previous radial keratotomy (RK) presents a challenging task. Different techniques have been used with varying outcomes. This study aimed to systematically review published articles on refractive surgeries in post-RK patients by conducting a search on PubMed, Scopus, and Web of Science. The final analysis included 35 studies that described a total of 888 eyes. Our systematic review and meta-analysis demonstrated a significant improvement in uncorrected distance visual acuity (UDVA) for photorefractive keratectomy (PRK), topography-guided PRK, wavefront-guided PRK, and femtosecond laser-assisted in situ keratomileusis (LASIK) while mechanical microkeratome LASIK did not yield such significant improvements. Moreover, our results suggest that post-RK patients with hyperopia had a significant improvement in UDVA, whereas no such improvement was observed in patients with myopia.
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Affiliation(s)
- Nima Koosha
- From the Isfahan Eye Research Center, Department of Ophthalmology, Isfahan University of Medical Sciences, Isfahan, Iran (Koosha, Riazi, Janfaza, Mohammadbeigy, Pourazizi, Peyman); Health Information Technology Research Center, Isfahan University Medical Sciences, Isfahan, Iran (Rahimi); Child Growth and Development Research Center, Research Institute for Primordial Prevention of Non-communicable Disease, Isfahan University of Medical Sciences, Isfahan, Iran (Khoshali)
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Santhiago MR, Dutra BAL, Morgado CR, Seiler TG, Wendelstein J, Awwad ST, Assaf JF, Ghanem RC, Ghanem VC, Talley Rostov AR, Wiley WF. Therapeutic visual rehabilitation in a patient with high hyperopia and flat cornea years after radial keratotomy. J Cataract Refract Surg 2023; 49:649-653. [PMID: 37257174 DOI: 10.1097/j.jcrs.0000000000001196] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
A 51-year-old man was referred for refractive surgery evaluation. Spectacle dependence and poor visual quality in both eyes was his chief complaint. He cannot tolerate contact lenses. Corrected distance visual acuity (CDVA) was 20/40 in both eyes. Manifest refraction was +5.25 -2.25 @ 90 (20/40) in the right eye and +6.25 -2.25 @ 105 (20/40) in the left eye. The patient had a history of radial keratotomy (RK) almost 30 years ago in both eyes and at the slitlamp presented 8 RK incisions, proportionally spaced between one another. All incisions were closed, and there were no relevant signs of scarring. The patient denied any history of ocular trauma, systemic disease, or medications. Corneal topography with different technologies revealed an irregular pattern with marked central flattening in both eyes, with some points below 30 diopters (D) (Supplemental Figures 1 and 2, available at http://links.lww.com/JRS/A862 and http://links.lww.com/JRS/A863, respectively). There were no signs of cataract, and fundus examination was normal. Optical coherence tomography (OCT) of the right eye revealed a more homogeneous thickness pattern, little variation between the thinnest and thickest areas, and adequate transparency (Figure 1JOURNAL/jcrs/04.03/02158034-202306000-00018/figure1/v/2023-05-31T172126Z/r/image-tiff). In the left eye, there is wide variability between the thinnest and thickest stromal points, with annular thinning and central thickening (Figure 2JOURNAL/jcrs/04.03/02158034-202306000-00018/figure2/v/2023-05-31T172126Z/r/image-tiff). Both eyes show marked epithelial irregularity. Considering this patient's current ocular status, how would you reach visual rehabilitation? Because he is contact lens intolerant, would you consider surface ablation, for example, photorefractive keratectomy (PRK) with mitomycin-C (MMC)? If that were the case, would you think of an optimized or a topography-guided (TG) treatment? Would you immediately consider a corneal transplant option? Would you instead consider a more conservative approach? Which one and why?
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Charpentier S, Keilani C, Maréchal M, Friang C, De Faria A, Froussart-Maille F, Delbarre M. Corneal haze post photorefractive keratectomy. J Fr Ophtalmol 2021; 44:1425-1438. [PMID: 34538661 DOI: 10.1016/j.jfo.2021.05.006] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2021] [Revised: 04/21/2021] [Accepted: 05/18/2021] [Indexed: 10/20/2022]
Abstract
Corneal haze represents subepithelial corneal fibrosis, a manifestation of a pathological healing process. It occurs as a result of an epithelial-stromal lesion involving a break in the epithelial barrier. It is an inflammatory response that involves the migration, multiplication and differentiation of keratocytes into mature myofibroblasts, causing loss of corneal transparency. Although it is a transient phenomenon, this complication is feared following refractive photokeratectomy (PRK), because it can cause alterations in the quality of vision, refractive regression and decreased visual acuity. The severity of these symptoms is correlated with the severity of the corneal haze, which can be assessed clinically or by objective means such as corneal densitometry measurement. The frequency and severity of corneal haze increase with the depth of photoablation in PRK and are therefore increased during the treatment of severe ametropia. Considering that no consensus exists, the application of mitomycin C (MMC) intraoperatively and topical corticosteroids postoperatively are conventionally used to inhibit collagen synthesis, sometimes in combination with various protocols depending on the center or surgeon. This review of the literature reports the current knowledge on corneal haze, in order to better understand it and optimise its prevention in the context of a decreased MMC supply, which has occurred in the past and could recur in the future.
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Affiliation(s)
- S Charpentier
- Service d'ophtalmologie, hôpital d'instruction des armées Bégin, 69, avenue de Paris, 94163 Saint-Mandé Cedex, France.
| | - C Keilani
- Service ophtalmologie, hôpital d'instruction des armées Percy, BP 406, 92141 Clamart Cedex, France
| | - M Maréchal
- Service ophtalmologie, hôpital d'instruction des armées Percy, BP 406, 92141 Clamart Cedex, France; Centre principal d'expertise du personnel naviguant, BP 406, 92141 Clamart Cedex, France
| | - C Friang
- Service ophtalmologie, hôpital d'instruction des armées Percy, BP 406, 92141 Clamart Cedex, France; Centre principal d'expertise du personnel naviguant, BP 406, 92141 Clamart Cedex, France
| | - A De Faria
- Service ophtalmologie, hôpital d'instruction des armées Percy, BP 406, 92141 Clamart Cedex, France; Centre principal d'expertise du personnel naviguant, BP 406, 92141 Clamart Cedex, France
| | - F Froussart-Maille
- Service ophtalmologie, hôpital d'instruction des armées Percy, BP 406, 92141 Clamart Cedex, France; Centre principal d'expertise du personnel naviguant, BP 406, 92141 Clamart Cedex, France; École du Val-de-Grâce, 1, place Alphonse Laveran, 75230 Paris Cedex 05, France
| | - M Delbarre
- Service ophtalmologie, hôpital d'instruction des armées Percy, BP 406, 92141 Clamart Cedex, France; Centre principal d'expertise du personnel naviguant, BP 406, 92141 Clamart Cedex, France
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Carlos de Oliveira R, Wilson SE. Biological effects of mitomycin C on late corneal haze stromal fibrosis following PRK. Exp Eye Res 2020; 200:108218. [PMID: 32905844 DOI: 10.1016/j.exer.2020.108218] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2020] [Revised: 08/25/2020] [Accepted: 08/30/2020] [Indexed: 12/12/2022]
Abstract
This review details the current understanding of the mechanism of action and corneal effects of mitomycin C (MMC) for prophylactic prevention of stromal fibrosis after photorefractive keratectomy (PRK), and includes discussion of available information on dosage and exposure time recommended for MMC during PRK. MMC is an alkylating agent, with DNA-crosslinking activity, that inhibits DNA replication and cellular proliferation. It acts as a pro-drug and requires reduction in the tissue to be converted to an active agent capable of DNA alkylation. Although MMC augments the early keratocyte apoptosis wave in the anterior corneal stroma, its most important effect responsible for inhibition of fibrosis in surface ablation procedures such as PRK is via the inhibition of mitosis of myofibroblast precursor cells during the first few weeks after PRK. MMC use is especially useful when treating eyes with higher levels of myopia (≥approximately 6 D), which have shown higher risk of developing fibrosis (also clinically termed late haze). Studies have supported the use of MMC at a concentration of 0.02%, rather than lower doses (such as 0.01% or 0.002%), for optimal reduction of fibrosis after PRK. Exposure times for 0.02% MMC longer than 40 s may be beneficial for moderate to high myopia (≥6D), but shorter exposures times appear to be equally effective for lower levels of myopia. Although MMC treatment may also be beneficial in preventing fibrosis after PRK treatments for hyperopia and astigmatism, more studies are needed. Thus, despite the clinical use of MMC after PRK for nearly twenty years-with limited evidence of harmful effects in the cornea-many decades of experience will be needed to exclude late long-term effects that could be noted after MMC treatment.
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Affiliation(s)
| | - Steven E Wilson
- The Cole Eye Institute, Cleveland Clinic, Cleveland, OH, USA.
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Filev FS, Kromer R, Frings A, Dragneva D, Mitov T, Mitova D. [Photorefractive Keratectomy (PRK) as a Procedure for Correction of Residual Refractive Errors after Radial Keratotomy]. Klin Monbl Augenheilkd 2019; 237:961-967. [PMID: 31266074 DOI: 10.1055/a-0901-7544] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
Abstract
BACKGROUND A large number of myopic patients were treated by radial keratotomy (RK) in recent years. Despite being effective in many cases, the refractive results of this surgical intervention proved to be of limited predictability, and it frequently resulted in over- or under-correction in the long term. In this study, we discuss the intermediate and long-term results of a topography-guided photorefractive keratotomy (PRK) in a consecutive series of patients who were previously treated for myopia by radial keratotomy. MATERIALS AND METHODS In this retrospective case series, we examined the refraction and visual acuity in a consecutive series of patients-16 eyes-who were treated by PRK for residual refractive errors after radial keratotomy in the past. Mean follow up was 41 months (min. 9, max. 96). RESULTS All treated eyes showed an improvement in uncorrected visual acuity, and 56% had an improvement in corrected visual acuity. No serious or sight-threatening complications were recorded. Refraction was stable throughout the study period in all patients. CONCLUSIONS In this case series, photorefractive keratotomy was shown to be an effective treatment method for secondary ametropia after radial keratotomy. Apart from the correct planning and execution of the PRK, it is of critical importance to inform the patients about the limitations and the anticipated refractive result of the procedure.
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Affiliation(s)
| | - Robert Kromer
- Klinik für Augenheilkunde, Universitätsklinikum Hamburg-Eppendorf
| | - Andreas Frings
- Klinik für Augenheilkunde, Universitätsklinikum Düsseldorf
| | | | - Tosho Mitov
- Ophthalmology, St. Petka Eye Clinic, Varna, Bulgaria
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Corneal Breakthrough Haze After Photorefractive Keratectomy With Mitomycin C: Incidence and Risk Factors. Cornea 2018; 36:961-966. [PMID: 28542088 DOI: 10.1097/ico.0000000000001231] [Citation(s) in RCA: 34] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
PURPOSE To identify preoperative and intraoperative factors affecting breakthrough corneal haze incidence after photorefractive keratectomy (PRK) with mitomycin C (MMC). METHODS In this retrospective study of PRK performed at the Care Vision Refractive Laser Center, Tel Aviv, Israel, a total of 7535 eyes (n = 3854 patients; mean age ± SD, 26 ± 6 years; 55% men) underwent PRK with intraoperative MMC application. Patients with histories of corneal pathology or surgery were excluded. Incidence, time of onset, and corneal haze severity were documented on follow-up of 118 ± 110 days. Eyes were grouped by preoperative refraction [low (≤-3D), moderate (-3D to -6D), or high (>-6D) myopia; low (≤3D) or high (>3D) astigmatism; low or high hyperopia]; by intraoperative time (above or below 40 seconds); and by MMC application time (above or below 40 seconds). The main outcome measures were incidence, onset time, and severity of corneal haze. RESULTS The haze incidence was 2.1% in eyes with high myopia versus 1.1% in those with low to moderate myopia (P = 0.002), and 3.5 times higher in eyes with high than with low astigmatism (P < 0.05). The overall incidence was higher in eyes treated for hyperopia (10.8%) than for myopia (1.3%) (P = 0.0001). In eyes with moderate myopia, the haze incidence was lower in MMC application time ≥40 seconds (0%) than in <40 seconds (1.3%) (P = 0.03). After surgery, a mild early haze incidence peaked at 68.8 ± 6 days and severe late haze at 115 ± 17 days (P = 0.02). CONCLUSIONS Hyperopic and large myopic or astigmatic corrections carry higher risk of haze. Longer MMC application might have beneficial haze prevention.
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Malta JBNS, Kaz Soong H, Moscovici B, Campos M. Two-year follow-up of corneal cross-linking and refractive surface ablation in patients with asymmetric corneal topography. Br J Ophthalmol 2018; 103:137-142. [DOI: 10.1136/bjophthalmol-2017-310840] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2017] [Revised: 02/02/2018] [Accepted: 03/10/2018] [Indexed: 11/04/2022]
Abstract
AimsTo evaluate the safety and efficacy of corneal cross-linking (CXL) followed by photorefractive keratectomy (PRK) for refractive correction in patients with bilateral asymmetric topography.MethodsForty-four patients (88 eyes) were enrolled in this prospective randomised clinical trial. CXL with subsequent PRK after 6 months was performed in one eye (study group), and PRK alone was performed in contralateral eyes (control group). Patients were followed for 24 months after PRK. Outcome measures investigated included visual acuity (VA), refraction, aberrometry, topography, pachymetry and endothelial cell count. Groups were compared with linear mixed regression and repeated measures logistic regression. Multiple comparison adjustment with the Holm procedure was performed.ResultsAt baseline, the logMAR VA (best spectacle corrected) in study and control groups was 0.12±0.13 (mean±SD) and 0.08D±0.14, respectively, and axial inferior–superior index (IS) (topographic IS) in study and control groups were 0.59D±0.31D and 0.58D±0.32D, respectively. After 24 months, a mean under correction of −0.50D was observed in both groups. Change from baseline in logMAR VA in study and control groups was 0.00D±0.08D and −0.02D±0.10D, respectively. Frequency of haze at 30 months in study and control group eyes was, respectively, 18.2% and 4.6% (p=0.05). There was no statistical difference between groups in spherical aberration and coma after adjustment for multiple comparisons.ConclusionsNon-simultaneous CXL followed by PRK may be performed safely, and refractive results over a 2-year follow-up are highly similar in virgin and previously cross-linked corneas. Despite using mitomycin C, corneal haze can be significantly higher in the first year after PRK in eyes pretreated with CXL.
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Ghoreishi M, Peyman A, Koosha N, Golabchi K, Pourazizi M. Topography-guided transepithelial photorefractive keratectomy to correct irregular refractive errors after radial keratotomy. J Cataract Refract Surg 2018; 44:274-279. [DOI: 10.1016/j.jcrs.2017.12.015] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2017] [Revised: 11/24/2017] [Accepted: 12/04/2017] [Indexed: 10/17/2022]
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Martín-Escuer B, Alfonso JF, Esteve-Taboada JJ, Fernández-Vega Cueto L, Montés-Micó R. Implantation of Implantable Collamer Lenses After Radial Keratotomy. J Refract Surg 2017; 33:395-398. [PMID: 28586500 DOI: 10.3928/1081597x-20170426-01] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2017] [Accepted: 04/11/2017] [Indexed: 11/20/2022]
Abstract
PURPOSE To assess the predictability, efficacy, and safety of posterior chamber phakic implantable collamer lens (ICL) implantation after radial keratotomy. METHODS In a retrospective non-comparative interventional case series, outcomes in 6 consecutive eyes of 4 patients with residual refraction after radial keratotomy were analyzed after the implantation of ICLs. All of the lenses were implanted to correct the residual refractive error, ranging from -12.00 to +3.50 diopters (D) for sphere and from -0.75 to -3.75 D for cylinder. RESULTS The mean uncorrected distance visual acuity after ICL implantation was 0.31 ± 0.36 logMAR and the corrected distance visual acuity was 0.12 ± 0.10 logMAR. The mean efficacy index was 0.86. No eyes lost lines of visual acuity, two eyes did not change after surgery, two eyes gained one line, and two eyes gained two lines. The mean safety index was 1.17. No intraoperative complications were found and ICL explantation or repositioning was not required during the follow-up. No cases of cataract, pigment dispersion glaucoma, pupillary block, or other vision-threatening complications were found. CONCLUSIONS ICL implantation may be considered a reasonable surgical procedure for correcting residual refractive errors after radial keratotomy. [J Refract Surg. 2017;33(6):395-398.].
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Pinheiro FI, Araújo-Filho I, Meneses do Rego AC, Pereira de Azevedo E, Tabosa do Egito ES, Oréfice F, Alves de Souza Lima Filho A. New drug delivery system for corneal administration of mitomycin-C. J Cataract Refract Surg 2016; 42:1216-23. [PMID: 27531299 DOI: 10.1016/j.jcrs.2016.04.035] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2016] [Revised: 04/29/2016] [Accepted: 04/29/2016] [Indexed: 11/18/2022]
Abstract
PURPOSE To develop a new corneal release system to deliver optimum amounts of mitomycin-C (MMC) during the perioperative period of photorefractive keratectomy (PRK). SETTING Ophthalmos S/A, São Paulo, Brazil. DESIGN Experimental study. METHODS An in vitro experimental design was developed for studying a new MMC delivery system at a drug concentration of 0.02%. Whatman sterile filter paper disks with a diameter of 8.0 mm were impregnated with MMC solution. After drying, the disks were placed on agar plates seeded with Staphylococcus epidermidis; this was followed by instillation of a drop of sterile water. After 1 minute, the disks were removed and the plates were incubated for 48 hours at 35°C. The mean volume of the drops delivered from regular eyedrop bottles was determined, and the inhibition zone (in millimeters) was correlated with the amount of MMC loaded onto the disks. RESULTS Analysis of the inhibition zones produced by MMC indicated that 16 μg was the optimum dose to be incorporated in the disks. The mean volume of a drop delivered from eyedrop bottles was 37.7 μL. One minute after the application of a single drop of a balanced salt solution, the system released an adequate concentration of MMC for PRK. CONCLUSION A new delivery system for MMC was successfully developed for application during photorefractive keratectomy. FINANCIAL DISCLOSURE Dr. de Souza Lima Filho is the managing director of Ophtalmos S/A. Drs. de Souza Lima Filho, Irochima Pinheiro, and Oréfice have exclusive rights to intellectual property of this invention secured by a patent application filed with the Instituto Nacional da Propriedade Industrial.
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Affiliation(s)
- Francisco Irochima Pinheiro
- From the Graduate Program in Biotechnology (Pinheiro, Araújo-Filho, Rego, Azevedo), Potiguar University, the Laboratory of Dispersed Systems (Tabosa do Egito), Federal University of Rio Grande do Norte, Natal-RN, the Division of Uveitis, Brazilian Center for Visual Sciences (Oréfice), Belo Horizonte-MG, Ophthalmos S/A (Lima Filho), and the Department of Ophthalmology (Lima Filho), Federal University of São Paulo (USP), São Paulo, Brazil
| | - Irami Araújo-Filho
- From the Graduate Program in Biotechnology (Pinheiro, Araújo-Filho, Rego, Azevedo), Potiguar University, the Laboratory of Dispersed Systems (Tabosa do Egito), Federal University of Rio Grande do Norte, Natal-RN, the Division of Uveitis, Brazilian Center for Visual Sciences (Oréfice), Belo Horizonte-MG, Ophthalmos S/A (Lima Filho), and the Department of Ophthalmology (Lima Filho), Federal University of São Paulo (USP), São Paulo, Brazil.
| | - Amalia Cinthia Meneses do Rego
- From the Graduate Program in Biotechnology (Pinheiro, Araújo-Filho, Rego, Azevedo), Potiguar University, the Laboratory of Dispersed Systems (Tabosa do Egito), Federal University of Rio Grande do Norte, Natal-RN, the Division of Uveitis, Brazilian Center for Visual Sciences (Oréfice), Belo Horizonte-MG, Ophthalmos S/A (Lima Filho), and the Department of Ophthalmology (Lima Filho), Federal University of São Paulo (USP), São Paulo, Brazil
| | - Eduardo Pereira de Azevedo
- From the Graduate Program in Biotechnology (Pinheiro, Araújo-Filho, Rego, Azevedo), Potiguar University, the Laboratory of Dispersed Systems (Tabosa do Egito), Federal University of Rio Grande do Norte, Natal-RN, the Division of Uveitis, Brazilian Center for Visual Sciences (Oréfice), Belo Horizonte-MG, Ophthalmos S/A (Lima Filho), and the Department of Ophthalmology (Lima Filho), Federal University of São Paulo (USP), São Paulo, Brazil
| | - Eryvaldo Socrates Tabosa do Egito
- From the Graduate Program in Biotechnology (Pinheiro, Araújo-Filho, Rego, Azevedo), Potiguar University, the Laboratory of Dispersed Systems (Tabosa do Egito), Federal University of Rio Grande do Norte, Natal-RN, the Division of Uveitis, Brazilian Center for Visual Sciences (Oréfice), Belo Horizonte-MG, Ophthalmos S/A (Lima Filho), and the Department of Ophthalmology (Lima Filho), Federal University of São Paulo (USP), São Paulo, Brazil
| | - Fernando Oréfice
- From the Graduate Program in Biotechnology (Pinheiro, Araújo-Filho, Rego, Azevedo), Potiguar University, the Laboratory of Dispersed Systems (Tabosa do Egito), Federal University of Rio Grande do Norte, Natal-RN, the Division of Uveitis, Brazilian Center for Visual Sciences (Oréfice), Belo Horizonte-MG, Ophthalmos S/A (Lima Filho), and the Department of Ophthalmology (Lima Filho), Federal University of São Paulo (USP), São Paulo, Brazil
| | - Acácio Alves de Souza Lima Filho
- From the Graduate Program in Biotechnology (Pinheiro, Araújo-Filho, Rego, Azevedo), Potiguar University, the Laboratory of Dispersed Systems (Tabosa do Egito), Federal University of Rio Grande do Norte, Natal-RN, the Division of Uveitis, Brazilian Center for Visual Sciences (Oréfice), Belo Horizonte-MG, Ophthalmos S/A (Lima Filho), and the Department of Ophthalmology (Lima Filho), Federal University of São Paulo (USP), São Paulo, Brazil
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Tomás-Juan J, Murueta-Goyena Larrañaga A, Hanneken L. Corneal Regeneration After Photorefractive Keratectomy: A Review. JOURNAL OF OPTOMETRY 2015; 8:149-69. [PMID: 25444646 PMCID: PMC4502084 DOI: 10.1016/j.optom.2014.09.001] [Citation(s) in RCA: 62] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/28/2014] [Revised: 08/01/2014] [Indexed: 05/20/2023]
Abstract
Photorefractive keratectomy (PRK) remodels corneal stroma to compensate refractive errors. The removal of epithelium and the ablation of stroma provoke the disruption of corneal nerves and a release of several peptides from tears, epithelium, stroma and nerves. A myriad of cytokines, growth factors, and matrix metalloproteases participate in the process of corneal wound healing. Their balance will determine if reepithelization and stromal remodeling are appropriate. The final aim is to achieve corneal transparency for restoring corneal function, and a proper visual quality. Therefore, wound-healing response is critical for a successful refractive surgery. Our goal is to provide an overview into how corneal wounding develops following PRK. We will also review the influence of intraoperative application of mitomycin C, bandage contact lenses, anti-inflammatory and other drugs in preventing corneal haze and post-PRK pain.
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Affiliation(s)
- Javier Tomás-Juan
- Department of Visual Science, VallmedicVision International Eye Clinic, Andorra.
| | | | - Ludger Hanneken
- Department of Visual Science, VallmedicVision International Eye Clinic, Andorra
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Abstract
PURPOSE The aim of this study was to report the outcomes of corneal collagen crosslinking (CXL) after previous radial keratotomy (RK) in patients with decreasing visual acuity and/or diurnal visual fluctuations. METHODS The charts of all patients who had undergone CXL because of a worsening corrected distance visual acuity (CDVA) and/or diurnal visual fluctuations after RK were reviewed retrospectively. Uncorrected distance visual acuity, CDVA, manifest refraction, and corneal topography were recorded preoperatively and at 1, 3, 6, and 12 months after the procedure. RESULTS Nine eyes of 6 patients that had undergone an RK 15 to 23 years before the CXL were included in the study. In 5 patients (8 out of 9 eyes), discontinuation of diurnal visual fluctuation was reported between 6 and 12 months after the CXL. The mean uncorrected distance visual acuities pre and 12 months after the CXL were 0.7 logarithm of the minimum angle of resolution (logMAR) and 0.6 logMAR, respectively (P = 0.3). The mean CDVAs pre and 12 months after the CXL were 0.2 logMAR and 0.1 logMAR (P = 0.5), respectively. The mean average keratometry pre and 12 months after the CXL were 40.1 and 39.1 diopters (P = 0.06), respectively. The mean corneal astigmatism values pre and 12 months after the CXL were 2.3 and 1.9 diopters (P = 0.06), respectively. The mean manifest refraction spherical equivalents (MRSEs) before and 12 months after the CXL were +1.4 and +2.5 (P = 0.1), respectively. CONCLUSIONS CXL is a safe and effective method to restore corneal stability in eyes with a history of RK. However, some of the effect that was achieved at the 6-month visit was blunted at the 12-month visit. Therefore, a longer follow-up is necessary to validate these findings.
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Donnelly KS, Giuliano EA, Sharma A, Mohan RR. Suberoylanilide hydroxamic acid (vorinostat): its role on equine corneal fibrosis and matrix metalloproteinase activity. Vet Ophthalmol 2013; 17 Suppl 1:61-8. [DOI: 10.1111/vop.12129] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Affiliation(s)
- Kevin S. Donnelly
- Harry S. Truman Veterans Memorial Hospital; 800 Hospital Drive Columbia MO USA
- Department of Veterinary Medicine and Surgery; College of Veterinary Medicine; University of Missouri; 900 East Campus Drive Columbia MO USA
| | - Elizabeth A. Giuliano
- Department of Veterinary Medicine and Surgery; College of Veterinary Medicine; University of Missouri; 900 East Campus Drive Columbia MO USA
| | - Ajay Sharma
- Harry S. Truman Veterans Memorial Hospital; 800 Hospital Drive Columbia MO USA
- Mason Eye Institute; University of Missouri; 1 Hospital Drive Columbia MO USA
| | - Rajiv R. Mohan
- Harry S. Truman Veterans Memorial Hospital; 800 Hospital Drive Columbia MO USA
- Department of Veterinary Medicine and Surgery; College of Veterinary Medicine; University of Missouri; 900 East Campus Drive Columbia MO USA
- Mason Eye Institute; University of Missouri; 1 Hospital Drive Columbia MO USA
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Abstract
PURPOSE To provide an overview of the safety and efficacy of mitomycin C (MMC) as adjuvant therapy after refractive surgery procedures. METHODS Literature review. RESULTS Over the past 10 years, MMC has been used by refractive surgeons to prophylactically decrease haze after surface ablation procedures and therapeutically in the treatment of preexisting haze. Development of MMC treatments has had a significant role in the revival of surface ablation techniques. We reviewed the literature regarding mechanism of action of MMC, its role in modulating wound healing after refractive surgery, and its safety and efficacy as adjuvant therapy applied after primary photorefractive keratectomy surgery or after photorefractive keratectomy re-treatment after laser in situ keratomileusis and other corneal surgeries and disorders. The drug is a potent mitotic inhibitor that effectively blocks keratocyte activation, proliferation, and myofibroblast differentiation. Many studies have suggested that MMC is safe and effective in doses used by anterior surface surgeons, although there continue to be concerns regarding long-term safety. After initial depletion of anterior keratocytes, keratocyte density seems to return to normal 6 to 12 months after the use of MMC when corneas are examined with the confocal microscope. Most clinical studies found no difference between preoperative and postoperative corneal endothelial cell densities when MMC 0.02% was applied during refractive surgery, with exposure time of 2 minutes or less. CONCLUSIONS After more than 10 years of use, MMC has been found to be effective when used for prevention and treatment of corneal haze. Questions remain regarding optimal treatment parameters and long-term safety.
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Bosiack AP, Giuliano EA, Gupta R, Mohan RR. Efficacy and safety of suberoylanilide hydroxamic acid (Vorinostat) in the treatment of canine corneal fibrosis. Vet Ophthalmol 2011; 15:307-14. [PMID: 22212187 DOI: 10.1111/j.1463-5224.2011.00985.x] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
OBJECTIVE Study aims were to evaluate the safety and efficacy of the Food and Drug Administration-approved drug Vorinostat [suberoylanilide hydroxamic acid (SAHA)] in the treatment of canine corneal fibrosis using an in vitro model. METHODS Healthy donor canine corneas were collected and used to generate primary canine corneal fibroblasts (CCFs) by growing cultures in minimal essential medium supplemented with 10% fetal bovine serum. Canine corneal myofibroblasts, used as a model for corneal fibrosis, were produced by growing CCF cultures in serum-free medium containing transforming growth factor β1 (1 ng/mL). Trypan blue exclusion assays were used to determine the optimal SAHA dose for this in vitro model. Four hour after culturing with TGFβ1, CCF cultures were treated with 0.06% SAHA for 5 min (group 1) and for 24 h (group 2), representing single and multiple dose treatment regimes, respectively. Cultures were then further incubated in the presence of TGFβ1 (1 ng/μL) under serum-free conditions until they reached 70% confluence. Trypan blue exclusion, immunocytochemistry, and TUNEL assays were used to evaluate the cytotoxicity of SAHA. Real-time PCR, western blot analysis, and immunocytochemistry were used to determine the efficacy of SAHA to inhibit canine corneal myofibroblast formation. RESULTS Topical SAHA application in both treatment groups successfully decreased α-smooth muscle actin expression when compared to the TGFβ1 only treatment group (P < 0.05). Tested SAHA did not affect CCF phenotype or cellular viability and did not cause significant cell death. CONCLUSIONS Suberoylanilide hydroxamic acid safely and effectively inhibits TGFβ1-induced CCFs transformation to myofibroblast in vitro.
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Affiliation(s)
- Ann P Bosiack
- Harry S. Truman Veterans Memorial Hospital, Columbia, MO, USA
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Bosiack AP, Giuliano EA, Gupta R, Mohan RR. Canine corneal fibroblast and myofibroblast transduction with AAV5. Vet Ophthalmol 2011; 15:291-8. [DOI: 10.1111/j.1463-5224.2011.00980.x] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
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Woodward MA, Edelhauser HF. Corneal endothelium after refractive surgery. J Cataract Refract Surg 2011; 37:767-77. [PMID: 21420604 DOI: 10.1016/j.jcrs.2011.01.012] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2010] [Revised: 10/28/2010] [Accepted: 10/29/2010] [Indexed: 11/25/2022]
Abstract
UNLABELLED The endothelium is vital to the health and optical clarity of the human cornea. The safety of procedures to correct refractive errors depends on preservation of an intact corneal endothelium. Disease states and genetic and environmental factors affect the corneal endothelium; an unstable corneal endothelium can impact the success of refractive surgery. Technological advances and recent laboratory findings have improved the ability to assess the endothelium. The status of the corneal endothelium after laser in situ keratomileusis, photorefractive keratectomy, phakic intraocular lenses, and adjuvants to these treatments has been the topic of numerous clinical trials. Safety guidelines for refractive surgery procedures should be followed to minimize deleterious effects on the corneal endothelium. FINANCIAL DISCLOSURE Neither author has a financial or proprietary interest in any material or method mentioned.
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McAlinden C, Moore J. Laser-assisted subepithelial keratectomy retreatment surgery. J Cataract Refract Surg 2011; 37:358-63. [DOI: 10.1016/j.jcrs.2010.11.009] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2010] [Revised: 07/13/2010] [Accepted: 08/18/2010] [Indexed: 11/26/2022]
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Decision Making in Refractive Surgery. Cornea 2011. [DOI: 10.1016/b978-0-323-06387-6.00165-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
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Buss DG, Sharma A, Giuliano EA, Mohan RR. Efficacy and safety of mitomycin C as an agent to treat corneal scarring in horses using an in vitro model. Vet Ophthalmol 2010; 13:211-8. [PMID: 20618797 DOI: 10.1111/j.1463-5224.2010.00782.x] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
OBJECTIVE Mitomycin C (MMC) is used clinically to treat corneal scarring in human patients. We investigated the safety and efficacy of MMC to treat corneal scarring in horses by examining its effects at the early and late stages of disease using an in vitro model. PROCEDURE An in vitro model of equine corneal fibroblast (ECF) developed was used. The ECF or myofibroblast cultures were produced by growing primary ECF in the presence or absence of transforming growth factor beta-1 (TGFbeta1) under serum-free conditions. The MMC dose for the equine cornea was defined with dose-dependent trypan blue exclusion and (3-4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assays after applying MMC to the cultures once for 2 min. The efficacy of MMC to control corneal scarring in horses was determined by measuring mRNA and protein expression of corneal scarring markers (alpha-smooth muscle actin and F-actin) with western blotting, immunocytochemistry and/or quantitative real-time polymerase chain reactions. RESULTS A single 2-min treatment of 0.02% or less MMC did not alter ECF phenotype, viability, or cellular proliferation whereas 0.05% or higher MMC doses showed mild-to-moderate cellular toxicity. The TGFbeta1 at 1 ng/mL showed significant myofibroblast formation in ECF under serum-free conditions. A single 2-min, 0.02% MMC treatment 24 h (early) after TGFbeta1 stimulation significantly reduced conversion of ECF to myofibroblasts, however, a single 0.02% MMC treatment 11 days after TGFbeta1 stimulation showed moderate myofibroblast inhibition. CONCLUSIONS That MMC safely and effectively reduced scarring in ECF by reducing the degree of transdifferentiation of corneal fibroblasts to myofibroblasts in vitro. Further clinical in vivo investigations are warranted using MMC in horses.
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Affiliation(s)
- Dylan G Buss
- Harry S. Truman Memorial Veterans Hospital, Columbia, MO, USA
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de Benito-Llopis L, Teus MA. Efficacy of surface ablation retreatments using mitomycin C. Am J Ophthalmol 2010; 150:376-380.e2. [PMID: 20570239 DOI: 10.1016/j.ajo.2010.03.027] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2009] [Revised: 03/20/2010] [Accepted: 03/24/2010] [Indexed: 10/19/2022]
Abstract
PURPOSE To evaluate the visual and refractive results and the incidence of complications after laser subepithelial keratectomy (LASEK) enhancement using mitomycin C (MMC) after a previous LASEK procedure with MMC. DESIGN Retrospective, noncomparative, interventional case series. METHODS Setting was Vissum Santa Hortensia, Madrid, Spain. We performed a retrospective study of LASEK-treated eyes that received intraoperative MMC for 30 seconds and that needed an enhancement procedure. LASEK retreatment with MMC 0.02%, applied for 60 seconds, was performed 3 to 6 months after the initial surgery. We measured the visual and refractive results 3 months after the enhancement and the incidence of complications. RESULTS Eighty-two eyes were included in the study. The preoperative data were best spectacle-corrected visual acuity (BSCVA) 1.08 +/- 0.19, sphere -4.68 +/- 2.8 diopters (D), and cylinder -1.30 +/- 1.20 D. Three to 6 months postoperatively, before enhancement, the uncorrected VA (UCVA) was 0.59 +/- 0.2; the BSCVA, 0.976 +/- 0.2; the residual sphere, +0.17 +/- 0.7 D, and the cylinder, -0.39 +/- 0.5 D. Three months after retreatment, the UCVA was 0.93 +/- 0.1; the BSCVA, 0.977 +/- 0.1; the residual sphere, 0.09 +/- 0.3 D; and the residual cylinder, -0.2 +/- 0.3 D. The safety index after retreatment was 1.01 +/- 0.1, and the efficacy index was 0.96 +/- 0.1. No haze, no delay in epithelial healing, and no case of endothelial decompensation were detected. CONCLUSION Surface ablation retreatment using MMC seems to be effective to correct residual refractive errors after an initial surgery with MMC.
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Abstract
PURPOSE OF REVIEW Ametropia and astigmatism following successful penetrating keratoplasty can seriously impact a patient's quality of vision. Similar limitations can result following anterior lamellar keratoplasty (ALK) and Descemet's stripping endothelial keratoplasty (DSEK). These patients often suffer from aniseikonia and can be intolerant of spectacles and contact lenses. Refractive surgery can correct both ametropia and astigmatism following corneal transplantation and improve a patient's final visual outcome. The same methods used to correct naturally occurring refractive errors are being used with increasing success in patients who have undergone corneal transplants. RECENT FINDINGS Many refractive options are available to treat ametropia following penetrating keratoplasty. Incisional keratotomies have been employed to treat high amounts of astigmatism. Photorefractive keratectomy (PRK) and laser in-situ keratomileusis (LASIK) are also used to treat myopia, hyperopia and astigmatism. LASIK has been shown to have an overall better outcome compared to PRK; however, the use of mitomycin-C with PRK has improved results. Phakic and pseudophakic piggyback intraocular lenses are also being used to treat high degrees of ametropia and astigmatism; however, the long-term results are somewhat limited. SUMMARY Refractive surgery can improve the final visual outcome of patients who have undergone successful corneal transplantation. Currently available modalities provide many options for patients who are intolerant of spectacles and contact lenses. Continued advances and research will enable surgeons to optimize visual quality in postkeratoplasty patients.
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Buss DG, Giuliano EA, Sharma A, Mohan RR. Isolation and cultivation of equine corneal keratocytes, fibroblasts and myofibroblasts. Vet Ophthalmol 2010; 13:37-42. [PMID: 20149174 DOI: 10.1111/j.1463-5224.2009.00755.x] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
OBJECTIVE To establish an in vitro model for the investigation of equine corneal wound healing. To accomplish this goal, a protocol to isolate and culture equine corneal keratocytes, fibroblasts and myofibroblasts was developed. ANIMAL MATERIAL: Equine corneal buttons were aseptically harvested from healthy research horses undergoing humane euthanasia for reasons unrelated to this study. Slit-lamp biomicroscopy was performed prior to euthanasia by a board-certified veterinary ophthalmologist to ensure that all samples were harvested from horses free of anterior segment disease. PROCEDURE Equine corneal stroma was isolated using mechanical techniques and stromal sub-sections were then cultured. Customized media at different culture conditions was used to promote growth and differentiation of corneal stromal cells into keratocytes, fibroblasts and myofibroblasts. RESULTS Cell culture techniques were successfully used to establish a method for the isolation and culture of equine corneal keratocytes, fibroblasts and myofibroblasts. Immunohistochemical staining for alpha-smooth muscle and F-actin was used to definitively differentiate the three cell types. CONCLUSION Equine corneal stromal keratocytes, fibroblasts and myofibroblasts can be predictably isolated and cultured in vitro using this protocol.
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Affiliation(s)
- Dylan G Buss
- College of Veterinary Medicine, University of Missouri, Columbia, MO, USA
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Chang SW, Chou SF, Yu SY. Dexamethasone reduces mitomycin C-related inflammatory cytokine expression without inducing further cell death in corneal fibroblasts. Wound Repair Regen 2009; 18:59-69. [PMID: 20002897 DOI: 10.1111/j.1524-475x.2009.00551.x] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
The purpose of this study was to investigate the effect of dexamethasone (DEX) on mitomycin C (MMC)-induced inflammatory cytokine expression in corneal fibroblasts. Primary human corneal fibroblasts were treated with MMC, dexamethasone, or in combination. Morphological changes and cell growth were documented using phase-contrast microscopy and PicoGreen assay, respectively. Cell apoptosis was evaluated by annexin V/propidium iodide staining, whereas viability was tested by the live/dead assay and analyzed by flow cytometry. The relative expression of interleukin-8 and monocyte chemoattractant protein-1 was investigated with quantitative real-time polymerase chain reaction and enzyme-linked immunosorbent assay. Mitogen-activated protein kinase activation and mitogen-activated protein kinase phosphatase-1 expression were documented by Western blot analysis. We found that MMC induced corneal fibroblast elongation, apoptosis, and retarded cell growth, whereas DEX did not significantly alter cell morphology or viability. The combination of DEX and MMC did not induce additional apoptosis and cell death. DEX dose dependently down-regulated basal and MMC-induced interleukin-8 and monocyte chemoattractant protein-1 mRNA expression and protein secretion. DEX attenuated MMC-induced p38 and Jun N-terminal kinases activation and up-regulated expression. These suggested that DEX may inhibit MMC-induced interleukin-8 and monocyte chemoattractant protein-1 by up-regulating MKP-1 expression, which subsequently deactivated p38 and Jun N-terminal kinases activation. Combined MMC and DEX treatment may facilitate corneal wound healing.
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Affiliation(s)
- Shu-Wen Chang
- Department of Ophthalmology, Far Eastern Memorial Hospital, Ban-Chiao, Taipei, Taiwan.
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Abstract
Mitomycin C has played a deciding role in the current revival of excimer laser surface ablation techniques. We review the literature regarding mechanism of action of mitomycin C, histological effects on the cornea, and indications, dose, exposure time, and toxicity of mitomycin C in corneal refractive surgery. Mitomycin C is an alkylating agent with cytotoxic and antiproliferative effects that reduces the myofibroblast repopulation after laser surface ablation and, therefore, reduces the risk of postoperative corneal haze. It is used prophylactically to avoid haze after primary surface ablation and therapeutically to treat pre-existing haze. There is no definite evidence that establishes an exact diopter limit or ablation depth at which to apply prophylactic mitomycin C. It is usually applied at a concentration of 0.2mg/ml (0.02%) for 12 to 120 seconds over the ablated stroma, although some studies suggest that lower concentrations (0.01%, 0.002%) could also be effective in preventing haze when treating low to moderate myopia. This dose of mitomycin C has not been associated with any clinically relevant epithelial corneal toxicity. Its effect on the endothelium is more controversial: two studies report a decrease in endothelial cell density, but the majority of reports suggest that the endothelium is not altered. Regarding mitomycin C's effect on keratocyte population, although animal studies report keratocyte depletion after its use, longer follow-up suggested that the initial keratocyte depletion does not persist over time.
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Koch DD, Maloney R, Hardten DR, Dell S, Sweeney AD, Wang L. Wavefront-guided photorefractive keratectomy in eyes with prior radial keratotomy: a multicenter study. Ophthalmology 2009; 116:1688-1696.e2. [PMID: 19643486 DOI: 10.1016/j.ophtha.2009.05.013] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2008] [Revised: 05/08/2009] [Accepted: 05/08/2009] [Indexed: 11/16/2022] Open
Abstract
PURPOSE To investigate the outcomes of wavefront-guided photorefractive keratectomy (WG PRK) using prophylactic mitomycin C (MMC) in eyes that had previously undergone radial keratotomy (RK). DESIGN Retrospective, observational, consecutive case series. PARTICIPANTS Thirty-two eyes of 27 patients with previous RK that underwent WG PRK with MMC. METHODS The records were reviewed of consecutive RK patients whose eyes underwent WG PRK with MMC in 4 centers with postoperative follow-up of 6 months or longer (range, 6-21 months). Eyes were divided into myopic WG PRK and hyperopic WG PRK groups based on their preoperative spherical equivalent (SE). Preoperative best spectacle-corrected visual acuity (BSCVA) was compared with postoperative uncorrected visual acuity (UCVA) and BSCVA to ascertain efficacy and safety. Change in SE and attempted versus achieved SE were evaluated. Incidences of haze and other complications were recorded. MAIN OUTCOME MEASURES Uncorrected visual acuity, BSCVA, SE, corneal haze, and other complications. RESULTS In the myopic WG PRK group (n = 9), UCVA improved by 3 lines on average (P = 0.015) with UCVA of > or =20/20 in 56% and > or =20/40 in 100% of eyes; 55% were within 0.5 diopter (D), and 100% were within 1 D of attempted refraction. In the hyperopic WG PRK group (n = 23), UCVA improved for 3 lines on average (P<0.001), with UCVA of > or =20/20 in 48% and > or =20/40 in 100% of eyes; 57% were within 0.5 D and 74% were within 1 D of attempted refraction. One eye lost 2 lines of BSCVA as a result of the development of mild to moderate haze, but recovered in 4 months. No eyes lost more than 2 lines of BSCVA. Six eyes (19%; 6/32) experienced the development of haze in the postoperative course, with mild to moderate haze in 1 eye and trace haze in the other 5 eyes. No other complications were noted. CONCLUSIONS Wavefront-guided PRK with MMC in eyes with prior RK improved the UCVA significantly and was safe over the short follow-up of this series. Although haze occurred, no eye suffered persistent visual loss of 2 or more lines. FINANCIAL DISCLOSURE(S) Proprietary or commercial disclosure may be found after the references.
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Affiliation(s)
- Douglas D Koch
- Department of Ophthalmology, Baylor College of Medicine, 6565 Fannin Street, Houston, TX 77030, USA.
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Photorefractive Keratectomy With Mitomycin-C for Consecutive Hyperopia After Radial Keratotomy. Cornea 2009; 28:371-4. [DOI: 10.1097/ico.0b013e31818c4d47] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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Alió JL, Piñero DP, Plaza Puche AB. Corneal wavefront-guided photorefractive keratectomy in patients with irregular corneas after corneal refractive surgery. J Cataract Refract Surg 2008; 34:1727-35. [DOI: 10.1016/j.jcrs.2008.06.025] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2008] [Accepted: 06/11/2008] [Indexed: 10/21/2022]
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Nassiri N, Farahangiz S, Rahnavardi M, Rahmani L, Nassiri N. Corneal endothelial cell injury induced by mitomycin-C in photorefractive keratectomy: Nonrandomized controlled trial. J Cataract Refract Surg 2008; 34:902-8. [DOI: 10.1016/j.jcrs.2008.03.007] [Citation(s) in RCA: 57] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2007] [Accepted: 03/02/2008] [Indexed: 10/22/2022]
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Thornton I, Xu M, Krueger RR. Comparison of standard (0.02%) and low dose (0.002%) mitomycin C in the prevention of corneal haze following surface ablation for myopia. J Refract Surg 2008; 24:S68-76. [PMID: 18269154 DOI: 10.3928/1081597x-20080101-13] [Citation(s) in RCA: 49] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
PURPOSE To retrospectively compare the safety and efficacy of lower dose mitomycin C (MMC) (0.002%) to that of the standard dose (0.02%) in eyes treated with photorefractive keratectomy (PRK) for myopia. METHODS The clinical efficacy of 95 eyes receiving myopic PRK with a standard concentration of MMC (0.02%) is sequentially compared to 126 eyes receiving low dose MMC (0.002%). The topical exposure times for MMC varied between 30 seconds and 2 minutes in both groups, and direct contralateral eye comparison of these two exposure times was analyzed in a prospective subset of 39 patients from among the low dose group. Patients were examined preoperatively and postoperatively at 1, 3, 6-9, and 9-12 months. Haze, visual acuity, and efficacy ratio outcomes were analyzed. RESULTS The preoperative findings were overall statistically similar, except for higher spherical equivalent refractive error (P = .007) and best spectacle-corrected visual acuity (P = .007) in the standard MMC group. Postoperatively, haze levels ranged from 0 to 4+. With multivariable analysis, significantly less haze was noted among the standard dose MMC eyes for high myopia and higher ablation depth at all postoperative time points. In contrast, the haze levels were statistically similar for moderate myopia and lower ablation depths at the latter postoperative time points. The subset of contralateral eyes randomly receiving low dose MMC (0.002%) at either 30 seconds or 2 minutes exposure showed no significant difference in haze between these exposure times. CONCLUSIONS The standard concentration of topical MMC (0.02%) is more effective than low dose MMC (0.002%) in preventing postoperative haze following surface ablation for myopia > or = -6.00 D and deeper ablation depth > or = 75 microm. However, for moderate myopia and shallow depth, low dosing appears to be equally effective. The duration of MMC exposure appears to be less important than its concentration.
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Affiliation(s)
- Ivey Thornton
- Cole Eye Institute, Cleveland Clinic Foundation, Cleveland, Ohio 44195, USA
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Photorefractive Keratectomy With Mitomycin C After Deep Anterior Lamellar Keratoplasty for Keratoconus. Cornea 2008; 27:417-20. [DOI: 10.1097/ico.0b013e318164e4b8] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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Bibliography. Current world literature. Curr Opin Ophthalmol 2007; 18:342-50. [PMID: 17568213 DOI: 10.1097/icu.0b013e3282887e1e] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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