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Li A, Liu Z, Lin M, Gong Q, Wei L, Lu F, Hu L. Changes in Corneal Epithelial Thickness in Different Areas After Femtosecond Laser-Assisted LASIK in Patients With High Astigmatism. J Refract Surg 2024; 40:e239-e244. [PMID: 38593260 DOI: 10.3928/1081597x-20240311-04] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/11/2024]
Abstract
PURPOSE To explore changes in corneal epithelial thickness (CET) after femtosecond laser-assisted laser in situ keratomileusis in patients with high astigmatism. METHODS CET was measured at every intersection of the concentric circles and specific axes using AngioVue optical coherence tomography (Angio-OCT) preoperatively and 1 month postoperatively. The average thickness of corneal central, paracentral, and peripheral regions was the mean of the points within the central 2, 2 to 5, and 5 to 7 mm areas, respectively. Correlation analysis was performed to investigate the association between CET along different axes and other preoperative and postoperative parameters. RESULTS Forty-two eyes of 28 patients were included. CET along the astigmatic (K1) and perpendicular (K2) axes in the central and paracentral areas increased (P < .001), whereas that along the K2 axis decreased in the peripheral area 1 month postoperatively (P = .001). The amount of CET change in the peripheral area between the K1 and K2 axes was significantly different (P < .001). In the central area, the change in CET along the K2 axis was positively correlated with ablation depth (r = 0.315, P = .042) and negatively with refractive power after surgery (r = -0.347, P = .024). In the peripheral area, the changes in CET along both K1 and K2 axes were negatively correlated with ablation depth (r = -0.431, P = .004; r = -0.387, P = .011, respectively). CONCLUSIONS Epithelial modeling differed between the different astigmatism axes after refractive surgery. The compensatory response of the corneal epithelium is more pronounced along the steeper axis. [J Refract Surg. 2024;40(4):e239-e244.].
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Ye Y, Hou X, Yu N, Chen P, Zhuang J, Yu K. Corneal Epithelial Remodeling Induced by Photorefractive Keratectomy Enhancement After Small-Incision Lenticule Extraction. Transl Vis Sci Technol 2024; 13:14. [PMID: 38231497 PMCID: PMC10795581 DOI: 10.1167/tvst.13.1.14] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2023] [Accepted: 11/25/2023] [Indexed: 01/18/2024] Open
Abstract
Purpose To assess changes in corneal epithelial thickness (ET) within 9-mm diameter cornea after photorefractive keratectomy (PRK) retreatment after small-incision lenticule extraction (SMILE). Methods A total of 28 eyes of 19 patients with mean spherical equivalent of -1.30 ± 0.60 D who underwent retreatment after SMILE were included in this retrospective study. ET mapped across a 9-mm diameter area was obtained using wide-field optical coherence tomography (OCT) before and at one, three, and six months after surgery. The ET changes were compared between the different time points and analyzed zones. Results Before enhancement, the ET were 63.64 ± 6.01 µm and 61.25 ± 4.32 µm in central and paracentral zones, respectively. The ET of central and paracentral zones significantly decreased at one month and subsequently increased until six months. Six months after surgery, significant epithelial thickening occurred in 2- to 9-mm diameter cornea (all P < 0.05), whereas no significant change was observed in central 2-mm diameter cornea (P = 0.460). There was no significant difference in the ET between the central and paracentral zones (P = 1.00). The degree of myopic correction significantly correlated with the average ET in the central (P = 0.046) and paracentral (P = 0.033) zones at six months after PRK enhancement. No significant correlation was detected between the average ET of all zones and the postoperative spherical equivalent at six months after surgery (all P > 0.05). Conclusions PRK enhancement did not alter the overall trend of corneal epithelial remodeling induced by SMILE. An asymmetric and flatter lenticule-like pattern of epithelial remodeling was observed six months after surgery, which did not affect the refractive outcomes. Translational Relevance An asymmetric and centrally flattened lenticule-like pattern of epithelial remodeling was observed after PRK enhancement. Surgeons should consider expanding the intended optical zones for enhancement surgery after SMILE.
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Affiliation(s)
- Yiming Ye
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-Sen University, Guangzhou, China
- Guangdong Provincial Key Laboratory of Ophthalmology and Visual Science, Guangzhou, China
- Guangdong Provincial Clinical Research Center for Ocular Diseases, Guangzhou, China
| | - Xiangtao Hou
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-Sen University, Guangzhou, China
- Guangdong Provincial Key Laboratory of Ophthalmology and Visual Science, Guangzhou, China
- Guangdong Provincial Clinical Research Center for Ocular Diseases, Guangzhou, China
| | - Na Yu
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-Sen University, Guangzhou, China
- Guangdong Provincial Key Laboratory of Ophthalmology and Visual Science, Guangzhou, China
- Guangdong Provincial Clinical Research Center for Ocular Diseases, Guangzhou, China
| | - Pei Chen
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-Sen University, Guangzhou, China
- Guangdong Provincial Key Laboratory of Ophthalmology and Visual Science, Guangzhou, China
- Guangdong Provincial Clinical Research Center for Ocular Diseases, Guangzhou, China
| | - Jing Zhuang
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-Sen University, Guangzhou, China
- Guangdong Provincial Key Laboratory of Ophthalmology and Visual Science, Guangzhou, China
- Guangdong Provincial Clinical Research Center for Ocular Diseases, Guangzhou, China
| | - Keming Yu
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-Sen University, Guangzhou, China
- Guangdong Provincial Key Laboratory of Ophthalmology and Visual Science, Guangzhou, China
- Guangdong Provincial Clinical Research Center for Ocular Diseases, Guangzhou, China
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Lyra AFV, Alves EM, Montenegro AA, Parente NS, Cardoso MT, Alves LM, Maia CB, Fontes BM, Nose W. Corneal Higher Order Aberrations and Epithelial Remodeling With Femtosecond Laser-Assisted LASIK Topography-guided and Customized Asphericity Ablation in the Contralateral Eye: A Randomized, Double-Blind, Prospective Study. J Refract Surg 2023; 39:751-758. [PMID: 37937761 DOI: 10.3928/1081597x-20230925-03] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2023]
Abstract
PURPOSE To evaluate refractive results, corneal higher order aberrations (HOAs), and epithelial remodeling in the preoperative and postoperative period of regular corneas that had topography-guided femtosecond laser-assisted laser in situ keratomileusis (LASIK) (Contoura WaveLight; Alcon Laboratories, Inc) and compare them with the contralateral eye that underwent ablation customized by asphericity (Custom-Q WaveLight; Alcon Laboratories, Inc) in myopic eyes with or without astigmatism. METHODS A prospective, randomized, and double-blind study was conducted. Patients underwent preoperative and postoperative epithelial mapping and corneal tomography to assess the epithelial thickness map, HOAs of the corneal anterior surface, visual acuity, and refractive evaluation. RESULTS This study enrolled 96 normal eyes of 48 patients. Uncorrected distance visual acuity of 20/20 or better was achieved in 97% of patients and gains in corrected distance visual acuity and effectiveness in correcting refractive astigmatism were similar in both techniques. Seventeen sectors of the corneal epithelium map were assessed by spectral-domain optical coherence tomography and no significant differences were found between techniques preoperatively and postoperatively (P > .05). HOA root mean square, coma Z3±1, trefoil Z3-3, and tissue consumption exhibited statistically significant between-technique differences (P < .05). CONCLUSIONS The Contoura and Custom-Q techniques were similar with respect to refractive and visual outcomes after 3 months, as well as in epithelial remodeling. The Contoura provides lower postoperative HOA root mean square, coma Z3±1, and trefoil Z3-3 values, but the techniques showed no differences in the correction of the corneal astigmatic wavefront component and in the spherical aberration after 3 months. [J Refract Surg. 2023;39(11):751-758.].
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Feng Y, Reinstein DZ, Nitter T, Archer TJ, McAlinden C, Chen X, Bertelsen G, Utheim TP, Stojanovic A. Heidelberg Anterion Swept-Source OCT Corneal Epithelial Thickness Mapping: Repeatability and Agreement With Optovue Avanti. J Refract Surg 2022; 38:356-363. [PMID: 35686707 DOI: 10.3928/1081597x-20220414-01] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Abstract
PURPOSE To assess the repeatability of corneal epithelial thickness mapping in virgin, post-laser refractive surgery (PLRS), and keratoconic eyes using a novel swept-source optical coherence tomographer (SS-OCT), and to determine the agreement of the measurements with a validated spectral-domain (SD) OCT. METHODS Analysis of 90 virgin, 46 PLRS, and 122 keratoconic eyes was performed. Three consecutive measurements of each eye were acquired with the Anterion SS-OCT and Avanti SD-OCT devices, and averages of the epithelial thickness mapping were calculated in the central 2-mm zone and in the 2- to 5-mm and 5- to 7-mm diameter rings. The repeatability was analyzed using pooled within-subject standard deviation (Sw). The agreement was assessed by Bland-Altman analysis and paired t tests. RESULTS The repeatability ranges of the Anterion and Avanti epithelial thickness mapping measurements were Sw: 0.60 to 1.36 µm and Sw: 0.75 to 1.96 µm, respectively. The 95% limits of agreement of the Anterion and Avanti were 0.826 to 8.297. All values of the thickness measurements with the Anterion were lower than those of the Avanti, with the mean differences being 4.06 ± 1.81, 3.26 ± 2.52, and 3.68 ± 2.51 µm in virgin, PLRS, and keratoconic eyes, respectively (P < .001 for all). CONCLUSIONS The repeatability of the Anterion's epithelial thickness mapping was higher than that of the Avanti. In terms of the agreement between the Anterion and Avanti, the epithelium measured by the Anterion was always thinner than that of the Avanti, making their interchangeable use unsuitable without corrections. [J Refract Surg. 2022;38(6):356-363.].
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Wu Y, Sun S, Liu Z, Wang S, Wang G, Zhao S, Wei R, Huang Y. Changes in asphericity of anterior and posterior corneal surfaces for mild–moderate and high myopia after topography-guided FS-LASIK. Int Ophthalmol 2022; 42:3555-3565. [DOI: 10.1007/s10792-022-02356-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2021] [Accepted: 04/18/2022] [Indexed: 10/18/2022]
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Sun M, Cogswell D, Adams S, Ayoubi Y, Kumar A, Reljic T, Avila MY, Margo CE, Espana EM. Downregulation of collagen XI during late postnatal corneal development is followed by upregulation after injury. J Cell Sci 2022; 135:273967. [PMID: 34854919 PMCID: PMC8767274 DOI: 10.1242/jcs.258694] [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: 03/24/2021] [Accepted: 11/18/2021] [Indexed: 01/14/2023] Open
Abstract
Collagen XI plays a role in nucleating collagen fibrils and in controlling fibril diameter. The aim of this research was to elucidate the role that collagen XI plays in corneal fibrillogenesis during development and following injury. The temporal and spatial expression of collagen XI was evaluated in C57BL/6 wild-type mice. For wound-healing studies in adult mice, stromal injuries were created using techniques that avoid caustic chemicals. The temporal expression and spatial localization of collagen XI was studied following injury in a Col11a1 inducible knockout mouse model. We found that collagen XI expression occurs during early maturation and is upregulated after stromal injury in areas of regeneration and remodeling. Abnormal fibrillogenesis with new fibrils of heterogeneous size and shape occurs after injury in a decreased collagen XI matrix. In conclusion, collagen XI is expressed in the stroma during development and following injury in adults, and is a regulator of collagen fibrillogenesis in regenerating corneal tissue.
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Affiliation(s)
- Mei Sun
- From the Cornea, External Disease Service, Department of Ophthalmology, University of South Florida, Tampa, FL 33612, USA
| | - Devon Cogswell
- From the Cornea, External Disease Service, Department of Ophthalmology, University of South Florida, Tampa, FL 33612, USA
| | - Sheila Adams
- From the Cornea, External Disease Service, Department of Ophthalmology, University of South Florida, Tampa, FL 33612, USA
| | - Yasmin Ayoubi
- From the Cornea, External Disease Service, Department of Ophthalmology, University of South Florida, Tampa, FL 33612, USA
| | - Ambuj Kumar
- Research Methodology and Biostatistics Core, Morsani College of Medicine, University of South Florida, Tampa, FL 33612, USA
| | - Tea Reljic
- Research Methodology and Biostatistics Core, Morsani College of Medicine, University of South Florida, Tampa, FL 33612, USA
| | - Marcel Y. Avila
- Department of Ophthalmology, Universidad Nacional de Colombia, Bogota 111321, Colombia
| | - Curtis E. Margo
- From the Cornea, External Disease Service, Department of Ophthalmology, University of South Florida, Tampa, FL 33612, USA,Department of Pathology and Cell Biology, Morsani College of Medicine, University of South Florida, Tampa, FL 33612, USA
| | - Edgar M. Espana
- From the Cornea, External Disease Service, Department of Ophthalmology, University of South Florida, Tampa, FL 33612, USA,Department of Molecular Pharmacology and Physiology, University of South Florida, Tampa, FL 33612, USA,Author for correspondence ()
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Stewart S, Liu YC, Lin MTY, Mehta JS. Clinical Applications of In Vivo Confocal Microscopy in Keratorefractive Surgery. J Refract Surg 2021; 37:493-503. [PMID: 34236907 DOI: 10.3928/1081597x-20210419-01] [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] [Indexed: 11/20/2022]
Abstract
PURPOSE To review the contribution of in vivo confocal microscopy (IVCM) to the understanding of corneal wound healing following refractive surgery, and its role in the diagnosis and management of complications arising from keratorefractive procedures. METHODS Review of the basic science and clinical literature relating to the study of keratorefractive surgical procedures using IVCM. RESULTS Extensive research using IVCM has generated a comprehensive understanding of tissue responses after corneal refractive surgery. Epithelial thickness and stromal keratocyte density can be quantified postoperatively and studied longitudinally. Corneal nerve loss and subsequent reinnervation has been characterized and differs significantly between laser refractive techniques. IVCM has also been used to study complications arising from postoperative inflammation (diffuse lamellar keratitis, central toxic keratopathy, ring keratitis, and ectasia), infection (microbial keratitis), and neuropathy (dry eye and neuralgia). This imaging technique can have a critical role in the diagnosis of these complications and subsequent monitoring of treatment response. Manual processing of IVCM images is time-consuming and there may be significant interobserver and intraobserver variability with poor repeatability. However, increasing automation and the use of artificial intelligence is improving the speed and accuracy of image analysis. CONCLUSIONS IVCM has historically been confined to a research setting because image capture and subsequent processing was extremely labor intensive. However, advances in both hardware and software capabilities promise to allow the use of IVCM in routine clinical practice. Real-time evaluation of the cornea at a cellular level will be particularly useful in patients with inflammatory, infectious, or neuropathic complications of keratorefractive surgery. [J Refract Surg. 2021;37(7):493-503.].
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Zisimopoulos A, Vingopoulos F, Kanellopoulos AJ. Comparison of Planned Versus Achieved Central Stromal Thickness Reduction in LASIK Versus SMILE: A Contralateral Eye Study. J Refract Surg 2021; 37:454-459. [PMID: 34236905 DOI: 10.3928/1081597x-20210427-03] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
PURPOSE To compare attempted versus achieved corneal stromal thickness reduction in a consecutive case series of patients undergoing laser in situ keratomileusis (LASIK) in one eye and small incision lenticule extraction (SMILE) in the other eye. METHODS This prospective, randomized, contralateral eye study included 22 consecutive patients (44 eyes), one eye randomized to have myopic LASIK and the contralateral eye to have SMILE. Anterior segment optical coherence tomography was performed preoperatively and at 3 months postoperatively. For each of the treatment groups, the achieved maximum stromal thickness reduction was compared to the planned/attempted thickness. The deviation of planned versus achieved stromal thickness reduction was then compared between the two groups. RESULTS At 3 months postoperatively, LASIK had a lower difference between planned versus attempted stromal thickness reduction compared to SMILE (13.72 ± 14.45 vs 24.00 ± 19.45 µm, P = .03). Graphical analysis revealed this deviation to be exaggerated in higher myopic errors, when a higher maximum stromal reduction was planned. The mean stromal reduction thickness was 83.40 ± 29.52 µm achieved versus 97.13 ± 25.69 µm mean planned ablation depth in the LASIK group (P < .001) compared to 76.45 ± 29.69 µm achieved versus 100.45 ± 26.56 µm planned ablation depth in the SMILE group (P < .001). CONCLUSIONS LASIK had a significantly lower difference between planned versus achieved stromal thickness reduction when compared to SMILE (P = .03). This difference was more apparent in higher myopic corrections. [J Refract Surg. 2021;37(7):454-459.].
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Gad RE, Hosny M, Ahmed RA, Sherif AM, Salah Eldin Y. Contralateral Eye Study of Topography Guided versus Q Value Adjusted Photorefractive Keratectomy in Myopia and Myopic Astigmatism. Clin Ophthalmol 2021; 15:1735-1749. [PMID: 33935490 PMCID: PMC8080117 DOI: 10.2147/opth.s300232] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2021] [Accepted: 03/15/2021] [Indexed: 11/23/2022] Open
Abstract
Purpose of the Study To compare visual outcome, higher order aberrations (HOAs) of topography guided and Q value adjusted ablation in the fellow eye of patients undergoing photorefractive keratectomy (PRK) for the correction of myopia and myopic astigmatism. Methods Prospective randomized controlled interventional clinical study. The eyes of 52 patients undergoing PRK for myopia and astigmatism were included, that is, 104 eyes in total. In each patient, eyes were randomly allocated to group I: one eye received topography guided PRK using Contoura ablation software, or group II: the other eye received Q value adjusted PRK using Custom Q ablation software. Follow-Up Six months. Results At the end of 6 months, LogMAR UDVA was -0.04 ± 0.12 and -0.05 ± 0.11 (p = 0.688), while LogMAR CDVA was -0.06 ± 0.09 and -0.06 ± 0.1 in group I and group II, respectively (p = 0.972). Both groups showed a progressive oblate shift with time. This oblate shift was insignificantly less in group I by Topolyzer at 6mm, 15° and 30° at 6 months (p = 0.102, p = 0.138, p = 0.245, respectively). Topolyzer identified a significant difference between the change in coma and trefoil in both groups at 6 months (p<0.001 and p = 0.001, respectively). This was caused by the significant worsening of coma in group II (p<0.001) and the significant improvement of trefoil in group I (p = 0.007). No significant difference was found between groups in the change of ISV or ABR (p = 0.955 and 0.982, respectively). Ablation depth is a significant predictor of ΔQ at 6mm, 15° and 30° (p = 0.009, 0.039 and 0, respectively). No significant difference was found in the Strehl ratio or contrast sensitivity, although they were insignificantly better in group I (p = 0.785 and p = 0.745, respectively). Conclusion TG PRK and CQ PRK yielded similar results regarding UDVA, CDVA, MRSE, safety, predictability and contrast sensitivity. Both groups showed a progressive oblate shift, which was less in the TG group but the difference was statistically insignificant. TG PRK showed significantly improved trefoil HOA as compared to CQ PRK.
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Affiliation(s)
- Rania E Gad
- Ophthalmology Department, Helwan University, Cairo, Egypt
| | - Mohamed Hosny
- Ophthalmology Department, Cairo University, Cairo, Egypt
| | - Rania A Ahmed
- Ophthalmology Department, Cairo University, Cairo, Egypt
| | - Ahmed M Sherif
- Ophthalmology Department, Cairo University, Cairo, Egypt
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Montorio D, Cennamo G, Menna F, Donna P, Napolitano P, Breve MA, Fiore U, Cennamo G, Rosa N. Evaluation of corneal structures in myopic eyes more than twenty-two years after photorefractive keratectomy. JOURNAL OF BIOPHOTONICS 2020; 13:e202000138. [PMID: 32668101 DOI: 10.1002/jbio.202000138] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/09/2020] [Revised: 07/05/2020] [Accepted: 07/12/2020] [Indexed: 06/11/2023]
Abstract
The aim of this study is to evaluate corneal epithelial thickness (CET), corneal densitometry (CD) in 84 myopic eyes (57 patients) more than 22 years after photorefractive keratectomy, using anterior segment-optical coherence tomography (AS-OCT) and Scheimpflug imaging system. The CET was significantly higher in all operated eyes than in unoperated eyes in central sector. A statistically significant increase in CD in corneal anterior layer of central sector was shown in groups of operated eyes with greater ablation depth respect to unoperated eyes. While there was no significant difference in CD between the operated eyes groups with lower ablation depth and unoperated eyes. A significant trend toward higher values in anterior CD with deeper ablations in central sector was found. These noninvasive imaging techniques allow to better understand the corneal remodeling process after photoablation and to monitor the patients over time.
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Affiliation(s)
- Daniela Montorio
- Department of Neurosciences, Reproductive Sciences and Dentistry, University of Naples Federico II, Naples, Italy
| | - Gilda Cennamo
- Eye Clinic, Public Health Department, University of Naples Federico II, Naples, Italy
| | - Feliciana Menna
- Department of Neurosciences, Reproductive Sciences and Dentistry, University of Naples Federico II, Naples, Italy
| | - Piero Donna
- Department of Neurosciences, Reproductive Sciences and Dentistry, University of Naples Federico II, Naples, Italy
| | - Pasquale Napolitano
- Department of Neurosciences, Reproductive Sciences and Dentistry, University of Naples Federico II, Naples, Italy
| | - Maria Angelica Breve
- Department of Neurosciences, Reproductive Sciences and Dentistry, University of Naples Federico II, Naples, Italy
| | - Ugo Fiore
- Department of Management and Quantitative Studies, Parthenope University, Naples, Italy
| | - Giovanni Cennamo
- Department of Neurosciences, Reproductive Sciences and Dentistry, University of Naples Federico II, Naples, Italy
| | - Nicola Rosa
- Department of Medicine, Surgery and Dentistry, "Scuola Medica Salernitana", University of Salerno, Salerno, Italy
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Abstract
PURPOSE Long-term evaluation of corneal epithelial thickness (ET) profile changes after photorefractive keratectomy (PRK) using Fourier-domain anterior segment optical coherence tomography. METHODS Three hundred twenty-six eyes of 163 patients were included in this prospective observational study. The corneal epithelial map was obtained across a 9-mm diameter area of the cornea before and up to 27 months after surgery. ET was assessed in 25 sectors and 4 annular zones (central 2 mm, paracentral 2-5 mm, midperipheral 5-7 mm, and peripheral 7-9 mm). RESULTS There was a significant reduction in mean ET in all zones 1 month after PRK. Subsequently, ET increased in all annular zones. The change in mean ET became stable in the midperipheral and peripheral zones at 3 to 6 months and in the central zone at 12 months, and it continued to increase in the paracentral zone even after 18 months after surgery. The ET was 3.40 μm and 4.05 μm in the central and paracentral zones at 6 months, respectively. Postoperative spherical equivalent changed significantly only from 1 to 3 months (P < 0.04). There was a significant correlation between postoperative spherical equivalent at month 1 and ET change in the paracentral and midperipheral zones (P < 0.027). CONCLUSIONS There is a significant reduction in ET 1 month after myopic PRK with a gradual thickening thereafter until it reaches stability at 12 months in the central zone. However, it continues to change even after 18 months in the paracentral zone. The greatest thickening is in the paracentral zone, followed by the central zone.
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Romito N, Trinh L, Goemaere I, Borderie V, Laroche L, Bouheraoua N. Corneal Remodeling After Myopic SMILE: An Optical Coherence Tomography and In Vivo Confocal Microscopy Study. J Refract Surg 2020; 36:597-605. [DOI: 10.3928/1081597x-20200713-01] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2020] [Accepted: 06/12/2020] [Indexed: 11/20/2022]
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Ryu IH, Kim WK, Nam MS, Kim JK, Kim SW. Reduction of corneal epithelial thickness during medical treatment for myopic regression following FS-LASIK. BMC Ophthalmol 2020; 20:296. [PMID: 32682402 PMCID: PMC7368729 DOI: 10.1186/s12886-020-01570-2] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2020] [Accepted: 07/14/2020] [Indexed: 11/10/2022] Open
Abstract
Background To evaluate corneal epithelial thickness change during medical treatment for eyes with myopic regression after femtosecond laser-assisted in situ keratomileusis (FS-LASIK). Methods This study included 84 eyes of 54 subjects diagnosed with myopic regression after FS-LASIK and treated using topical steroid and anti-glaucoma drugs. Corneal epithelial thickness was measured using Fourier-domain optical coherence tomography before and after treatment. Subjects were divided into three groups based on their corneal epithelial thickness at the time of myopic regression and regression analyses were used to investigate the association between corneal epithelial thickness, visual acuity, and refraction. Logistic regression and receiver operating characteristic (ROC) curve analysis was performed to determine whether corneal epithelial thickness could predict the success of treatment, improvements of ≥ two lines in uncorrected distance visual acuity and ≥ 0.5 diopter in refraction or K. Results Corneal epithelial thickness decreased with greater change in the center as myopic regression subsided during medical treatment. Subgroup with the thickest epithelium (≥ 62 μm) showed a higher success rate and greater changes in refraction and vision. Reduced magnitude of corneal epithelial thickness showed significant correlations with changes of K and refractive error (all P < 0.001). Corneal epithelial thickness was a significant factor for the success of treatment and ROC curve showed that corneal epithelial thickness > 60.50 μm had 81.5% sensitivity and 84.2% specificity for the success of medical treatment. Conclusion Corneal epithelial thickness decreases proportionally with the magnitude of improvement of myopic regression during treatment with steroid and anti-glaucoma drugs in post-LASIK eyes with myopic regression.
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Affiliation(s)
| | | | - Myoung Sik Nam
- Department of Ophthalmology, Yonsei University Wonju College of Medicine, 20, Ilsan-ro, Wonju, Gangwon-do, 26426, South Korea
| | | | - Sun Woong Kim
- Department of Ophthalmology, Yonsei University Wonju College of Medicine, 20, Ilsan-ro, Wonju, Gangwon-do, 26426, South Korea.
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Sedaghat MR, Momeni-Moghaddam H, Gazanchian M, Reinstein DZ, Archer TJ, Randleman JB, Hosseini SR, Nouri-Hosseini G. Corneal Epithelial Thickness Mapping After Photorefractive Keratectomy for Myopia. J Refract Surg 2020; 35:632-641. [PMID: 31610004 DOI: 10.3928/1081597x-20190826-03] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2019] [Accepted: 08/26/2019] [Indexed: 11/20/2022]
Abstract
PURPOSE To evaluate the longitudinal changes in epithelial thickness after photorefractive keratectomy (PRK) and correlate these with refractive changes. METHODS This prospective study included 52 eyes of 52 candidates for myopic PRK. Along with standard ophthalmic examinations, corneal epithelial thickness mapping by anterior segment optical coherence tomography was performed. Epithelial thickness maps of 9-mm diameter were divided into 25 sectors, including a central 2-mm zone and eight octants within para-central (2 to 5 mm), midperipheral (5 to 7 mm), and peripheral (7 to 9 mm) annular zones. All PRK treatments were performed using the Technolas Teneo 317 model 2 excimer laser (Bausch & Lomb, Rochester, NY) and an aspheric profile with a 6-mm diameter optical zone. Follow-up was at 1, 3, and 6 months. RESULTS Repeated thickness measures before and after PRK at different follow-up times showed a significant difference in thickness separately in various zones (P < .001). A significant decrease in thickness was seen 1 month after PRK in all zones. Afterward, epithelial thickening continued in all zones and reached the preoperative thickness in the midperipheral and peripheral zones 6 months later, whereas the thickness in the central 5-mm zone was significantly thicker than before surgery. There was also a significant correlation between changes in spherical equivalent and epithelial thickness from before to 6 months postoperatively in the paracentral and peripheral zones. CONCLUSIONS There was a marked decrease in the epithelial thickening pattern at 1 month after PRK, with gradual thickening at 3 and 6 months. Changes in epithelial thickness and spherical equivalent were significant only for the para-central peripheral zone. [J Refract Surg. 2019;35(10):632-641.].
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Khamar P, Chandapura R, Shetty R, Dadachanji Z, Kundu G, Patel Y, Nuijts RM, Sinha Roy A. Epithelium Zernike Indices and Artificial Intelligence Can Differentiate Epithelial Remodeling Between Flap and Flapless Refractive Procedures. J Refract Surg 2020; 36:97-103. [DOI: 10.3928/1081597x-20200103-01] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2019] [Accepted: 01/02/2020] [Indexed: 11/20/2022]
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Kang DSY, Kim SW. Effect of Corneal Cross-linking on Epithelial Hyperplasia and Myopia Regression After Transepithelial Photorefractive Keratectomy. J Refract Surg 2019; 35:354-361. [PMID: 31185100 DOI: 10.3928/1081597x-20190422-01] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2018] [Accepted: 04/22/2019] [Indexed: 11/20/2022]
Abstract
PURPOSE To investigate the effect of accelerated corneal cross-linking (CXL) on epithelial thickness change and refractive outcome after myopic transepithelial photorefractive keratectomy (TPRK). METHODS This study compared epithelial thickness changes in 49 patients undergoing TPRK-CXL with 49 patients undergoing TPRK who were matched for age and refractive error. Corneal epithelial thickness, obtained using spectral-domain optical coherence tomography preoperatively and 12 months postoperatively, was compared between the groups. Regression analysis was performed to investigate the association between changes in epithelial thickness and keratometric power. Factors affecting myopic regression (> 0.50 diopters] were evaluated using logistic regression analysis. RESULTS For TPRK, the mean epithelial thickness of the center (2-mm diameter), paracenter (2- to 5-mm diameter), and pericenter (5- to 6-mm diameter) increased by 6.5 ± 3.1, 7.0 ± 2.9, and 4.9 ± 2.9 µm, respectively; increases of 4.8 ± 3.0, 5.9 ± 2.8, and 4.8 ± 2.7 µm were observed following TPRK-CXL, indicating a significant difference in the center (P = .013). Epithelial thickness increased linearly to the magnitude of myopic correction and was negatively correlated with the optical zone diameter of ablation. Change in epithelial thickness showed a linear correlation with the change in keratometric power between 1 and 12 months postoperatively, indicating regression in eyes following TPRK. Corneal epithelial thickening was significantly associated with myopic regression and simultaneous CXL tended to reduce the risk of regression. CONCLUSIONS TPRK-CXL induces less epithelial hyperplasia than does TPRK, presumably owing to the effect of CXL, and the magnitude of epithelial thickening seemed to be associated with myopic regression. [J Refract Surg. 2019;35(6):354-361.].
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Cho Y, Hieda O, Wakimasu K, Yamamura K, Yamasaki T, Nakamura Y, Sotozono C, Kinoshita S. Multiple Linear Regression Analysis of the Impact of Corneal Epithelial Thickness on Refractive Error Post Corneal Refractive Surgery. Am J Ophthalmol 2019; 207:326-332. [PMID: 31128091 DOI: 10.1016/j.ajo.2019.05.016] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2018] [Revised: 05/12/2019] [Accepted: 05/14/2019] [Indexed: 11/19/2022]
Abstract
PURPOSE To evaluate the influence of corneal epithelial thickness (CET) on the deviation from the targeted refraction (refractive error [RE]) post corneal refractive surgery. DESIGN Retrospective, single-center, cross-sectional study. METHODS This study involved 211 eyes of 211 patients who previously underwent laser-assisted in situ keratomileusis (LASIK) or epipolis LASIK for the correction of myopia and myopic astigmatism from August 2000 to May 2014 at the Baptist Eye Institute, Kyoto, Japan, and who subsequently underwent examination of CET via optical coherence tomography imaging of 17 zones (central: n = 1 zone, paracentral: n = 8 zones, and midperipheral: n = 8 zones) within a 6.0-mm-diameter area of the central cornea from April 2014 to February 2015. The relationship between CET and RE was evaluated using Spearman coefficient in 5 parameters: CET in the (1) central, (2) paracentral, and (3) midperipheral zones, and the difference between the (4) central and paracentral zones and the (5) central and midperipheral zones. The influence of CET on RE was evaluated in the CET parameter that showed a significant correlation with RE using multiple liner regression analysis. RESULTS The correlation coefficient with RE was (1) -0.238 (P < .01), (2) -0.172 (P < .05), (3) -0.002 (P = .98), (4) -0.186 (P < .01), and (5) -0.266 (P < .01), respectively. Multiple liner regression analysis revealed that the difference of mean CET between the central and midperipheral zones had a significant influence on RE (β coefficient = -0.028, P < .01). CONCLUSIONS The difference between CET at the central and midperipheral zones may play a role in the final RE post corneal refractive surgery.
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Affiliation(s)
- Yuko Cho
- Department of Ophthalmology, Kyoto Prefectural University of Medicine, Kyoto, Japan.
| | - Osamu Hieda
- Department of Ophthalmology, Kyoto Prefectural University of Medicine, Kyoto, Japan
| | | | | | | | - Yo Nakamura
- Department of Ophthalmology, Kyoto Prefectural University of Medicine, Kyoto, Japan
| | - Chie Sotozono
- Department of Ophthalmology, Kyoto Prefectural University of Medicine, Kyoto, Japan
| | - Shigeru Kinoshita
- Department of Frontier Medical Science and Technology for Ophthalmology, Kyoto Prefectural University of Medicine, Kyoto, Japan
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Wang Y, Ma J. Future Developments in SMILE: Higher Degree of Myopia and Hyperopia. Asia Pac J Ophthalmol (Phila) 2019; 8:412-416. [PMID: 31490200 PMCID: PMC6784781 DOI: 10.1097/01.apo.0000580128.27272.bb] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2019] [Accepted: 06/13/2019] [Indexed: 11/25/2022] Open
Abstract
Small incision lenticule extraction (SMILE) is a novel 1-step refractive procedure with femtosecond laser for the correction of myopia and myopic astigmatism. Although it has shown good clinical results in efficacy, safety, predictability, and stability, there are still some concerns. In this study, we review the published clinical outcomes of high myopia correction and exploration in hyperopia correction. Results have suggested that SMILE has acceptable outcomes in correction for high myopia <10.0 diopters (D), and it is a feasible and effective procedure for the treatment of hyperopia. However, it is unsuitable for the treatment of extremely high myopia because there is undercorrection and regression as existed in laser-assisted in situ keratomileusis (LASIK), and compound hyperopic astigmatism currently could not be corrected either. More technical and clinical improvements are required to make SMILE competitive.
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Affiliation(s)
- Yan Wang
- Tianjin Eye Hospital, Nankai University Affiliated Eye Hospital, Clinical College of Ophthalmology, Tianjin Medical University, Tianjin Eye Institute, Tianjin Key Laboratory of Ophthalmology and Visual Science, Tianjin, China
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Zhang L, Wang Y, Zhao W, Cheng W, Cui T. Corneal remodeling and spatial profiles following small incision lenticule extraction. Int Ophthalmol 2018; 39:1827-1836. [PMID: 30171445 DOI: 10.1007/s10792-018-1010-3] [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: 10/03/2017] [Accepted: 08/27/2018] [Indexed: 10/28/2022]
Abstract
PURPOSE To evaluate the three-dimensional corneal spatial profiles following small incision lenticule extraction (SMILE) based on corneal asphericity, thickness, and volume. MATERIALS AND METHODS Eighty-three eyes in 83 patients who underwent SMILE were examined before and 1 and 6 months after surgery. The asphericity of the anterior and posterior corneal surfaces was analyzed. Corneal volume (CV) was measured in corneal regions measuring 3.0 mm, 5.0 mm, and 7.0 mm in diameter. Mean corneal thickness (CT) values were acquired at the apex (0.0 mm) and in four concentric radial zones from the apex (with diameters of 2.0, 4.0, 6.0, and 8.0 mm). RESULTS The mean anterior Q value increased from - 0.32 preoperatively to 0.67 at 1 month and 0.62 at 6 months postoperatively. The mean posterior Q value decreased from - 0.30 preoperatively to - 0.26 at 1 month and to - 0.25 at 6 months postoperatively. The CV increased by 0.05 ± 0.06 mm3 (1.40%), 0.06 ± 0.11 mm3 (0.83%), and 0.09 ± 0.17 mm3 (0.73%) along the radial zones with respective diameters of 3.0 mm, 5.0 mm, and 7.0 mm. The CT increased by 6.02 ± 6.48 µm (1.36%) at the apex and then decreased with increasing distance from the center, i.e., to 5.52 ± 6.31 µm (1.20%) at 2.0 mm, 4.72 ± 6.55 µm (0.92%) at 4.0 mm, 4.47 ± 7.86 µm (0.75%) at 6.0 mm, and 4.86 ± 10.31 µm (0.70%) at 8.0 mm. No correlations were observed between changes in CV and CT and refractive fluctuation between 1 month and 6 months postoperatively. CONCLUSIONS The corneal profile displayed a less oblate shift on the anterior surface; however, the posterior surface showed a slight backward shift during the postoperative period. The CV and CT steadily increased after surgery and mainly within the operative zones. Refraction remained stable postoperatively and was not affected by the corneal remodeling.
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Affiliation(s)
- Lin Zhang
- Clinical College of Ophthalmology, Tianjin Medical University, Tianjin, China
| | - Yan Wang
- Clinical College of Ophthalmology, Tianjin Medical University, Tianjin, China. .,Tianjin Eye Hospital and Eye Institute, Tianjin Key Lab of Ophthalmology and Visual Science, Clinical College of Ophthalmology, Tianjin Medical University, No 4. Gansu Road, Heping District, Tianjin, 300020, China.
| | - Wei Zhao
- Clinical College of Ophthalmology, Tianjin Medical University, Tianjin, China
| | - Wenbo Cheng
- Clinical College of Ophthalmology, Tianjin Medical University, Tianjin, China
| | - Tong Cui
- Clinical College of Ophthalmology, Tianjin Medical University, Tianjin, China
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Jun I, Kang DSY, Arba-Mosquera S, Kim EK, Seo KY, Kim TI. Clinical Outcomes of Transepithelial Photorefractive Keratectomy According to Epithelial Thickness. J Refract Surg 2018; 34:533-540. [DOI: 10.3928/1081597x-20180618-02] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2018] [Accepted: 06/08/2018] [Indexed: 11/20/2022]
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Murueta-Goyena A, Cañadas P. Visual outcomes and management after corneal refractive surgery: A review. JOURNAL OF OPTOMETRY 2018; 11:121-129. [PMID: 29183707 PMCID: PMC5904824 DOI: 10.1016/j.optom.2017.09.002] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/27/2017] [Revised: 09/18/2017] [Accepted: 09/19/2017] [Indexed: 05/04/2023]
Abstract
Corneal refractive surgery procedures are widely performed to permanently correct refractive errors. Overall, refractive surgeries are safe, predictable and present high rates of satisfaction. Nevertheless, the induced epithelial, stromal and nerve damage alters corneal integrity and function, triggering a regenerative response. Complications that arise from corneal wound healing process might directly impact on visual outcomes of keratorefractive procedures. Most of these complications can be prevented or effectively treated with minimal consequences and minor impact on optical quality. Nevertheless, it is crucial to accurately and timely identify these corneal regeneration-related complications for successful counseling and management. Optometrists, as primary eye care providers, play an essential role in detecting anatomic and functional alterations in vision. It is therefore of great interest for optometrists to be familiar with the principal postoperative complications derived from alterations in regenerative process after corneal laser refractive surgeries. This review aims to provide a basis for optometrists to better understand, identify and manage the main wound healing-related complications after refractive surgery.
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Affiliation(s)
- Ane Murueta-Goyena
- Deparment of Neuroscience, University of the Basque Country (UPV/EHU), Leioa, Spain.
| | - Pilar Cañadas
- Instituto de Oftalmobiología Aplicada (IOBA) Grupo de Superficie Ocular, Universidad de Valladolid, Valladolid, Spain; Departamento de Física Teórica Atómica y Óptica, Universidad de Valladolid, Valladolid, Spain
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Dynamic Roles of the Corneal Epithelium in Refractive Surgery. CURRENT OPHTHALMOLOGY REPORTS 2017. [DOI: 10.1007/s40135-017-0149-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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Ryu IH, Kim BJ, Lee JH, Kim SW. Comparison of Corneal Epithelial Remodeling After Femtosecond Laser–Assisted LASIK and Small Incision Lenticule Extraction (SMILE). J Refract Surg 2017; 33:250-256. [DOI: 10.3928/1081597x-20170111-01] [Citation(s) in RCA: 43] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2016] [Accepted: 01/03/2017] [Indexed: 11/20/2022]
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Cornea donors who have had prior refractive surgery: data from the Eye Bank Association of America. Curr Opin Ophthalmol 2016; 27:323-6. [PMID: 27138639 DOI: 10.1097/icu.0000000000000278] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
PURPOSE OF REVIEW Millions of Americans have undergone refractive surgeries, including radial keratotomy, photorefractive keratectomy, and laser-assisted in situ keratomileusis. Eye Bank Association of America medical standards do not permit corneas from patients who have undergone refractive procedures to be used in penetrating keratoplasty, anterior lamellar keratoplasty, or tectonic grafting procedures. Such corneas, can, however, be used for endothelial corneal transplantation. The objective of this article is to provide an update on current trends for the screening and usage of corneas that have undergone refractive surgery. RECENT FINDINGS Several case reports have highlighted the difficulty in using postrefractive surgery corneas in penetrating keratoplasty. However, tissue with anterior stromal flaws, including a history of refractive surgery, has been used in endothelial keratoplasty with equivalent outcomes in topography, endothelial cell count, and visual acuity. Many modalities for proper identification of postmortem donor corneas that have undergone refractive surgery have been studied. SUMMARY Corneas with a history of refractive surgery have found use in endothelial keratoplasty. Multiple objective methods of tissue identification have been investigated to avoid the use of these corneas in penetrating or anterior keratoplasty surgeries.
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Corneal Epithelial Remodeling and Its Effect on Corneal Asphericity after Transepithelial Photorefractive Keratectomy for Myopia. J Ophthalmol 2016; 2016:8582362. [PMID: 27672447 PMCID: PMC5031833 DOI: 10.1155/2016/8582362] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2016] [Accepted: 07/28/2016] [Indexed: 11/18/2022] Open
Abstract
Purpose. To evaluate the changes in epithelial thickness profile following transepithelial photorefractive keratectomy (T-PRK) for myopia and to investigate the effect of epithelial remodeling on corneal asphericity. Methods. Forty-four patients (44 right eyes) who underwent T-PRK were retrospectively evaluated. Epithelial thickness was measured using spectral-domain optical coherence tomography at different corneal zones (central, 2 mm; paracentral, 2–5 mm; and mid-peripheral, 5-6 mm) preoperatively and at 1 week and 1, 3, and 6 months postoperatively. The correlation between the changes in corneal epithelial thickness (ΔCET) and postoperative Q-value changes (ΔQ) was analyzed 6 months postoperatively. Results. Epithelial thickness at 6 months showed a negative meniscus-like lenticular pattern with less central thickening, which increased progressively toward the mid-periphery (3.69 ± 4.2, 5.19 ± 3.8, and 6.23 ± 3.9 μm at the center, paracenter, and mid-periphery, resp., P < 0.01). A significant positive relationship was observed between epithelial thickening and ΔQ 6 months postoperatively (r = 0.438, 0.580, and 0.504, resp., P < 0.01). Conclusions. Significant epithelial thickening was observed after T-PRK and showed a lenticular change with more thickening mid-peripherally, resulting in increased oblateness postoperatively. Epithelial remodeling may modify the epithelial thickness profile after surface ablation refractive surgery for myopia.
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Fu D, Zhang ZY, Wang L, Zhou XT, Yu ZQ. Refractive Regression and Changes in Central Corneal Thickness Three Years after Laser-Assisted Subepithelial Keratectomy for High Myopia in Eyes with Thin Corneas: A Retrospective Study. Semin Ophthalmol 2016; 32:631-641. [PMID: 27367533 DOI: 10.3109/08820538.2016.1142579] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Affiliation(s)
- Dan Fu
- Department of Ophthalmology, Eye and ENT Hospital, Fudan University, Shanghai, PR China
| | - Zhen-Yong Zhang
- Department of Ophthalmology, Shanghai University of Traditional Chinese Medicine, Shanghai, PR China
| | - Lin Wang
- Department of Ophthalmology, Eye and ENT Hospital, Fudan University, Shanghai, PR China
| | - Xing-Tao Zhou
- Department of Ophthalmology, Eye and ENT Hospital, Fudan University, Shanghai, PR China
- Key Laboratory of Myopia, Ministry of Health, Shanghai, PR China
| | - Zhi-Qiang Yu
- Department of Ophthalmology, Eye and ENT Hospital, Fudan University, Shanghai, PR China
- Key Laboratory of Myopia, Ministry of Health, Shanghai, PR China
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Ganesh S, Brar S, Relekar KJ. Epithelial Thickness Profile Changes Following Small Incision Refractive Lenticule Extraction (SMILE) for Myopia and Myopic Astigmatism. J Refract Surg 2016; 32:473-82. [DOI: 10.3928/1081597x-20160512-01] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2015] [Accepted: 04/05/2016] [Indexed: 11/20/2022]
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Chan TCY, Yu MCY, Mak S, Jhanji V. Longitudinal comparison of femtosecond-assisted sub-Bowman keratomileusis versus photorefractive keratectomy for high myopia. Br J Ophthalmol 2016; 101:275-282. [DOI: 10.1136/bjophthalmol-2016-308642] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/29/2016] [Revised: 05/04/2016] [Accepted: 05/15/2016] [Indexed: 11/04/2022]
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Abstract
Purpose: To compare changes in the corneal thickness profile before and 6 months after femtosecond laser in situ keratomileusis (LASIK) for hyperopia. Methods: In a prospective noncomparative case series study, 24 eyes of 20 hyperopic patients undergoing femtosecond LASIK were examined preoperatively and 6 months postoperatively. Corneal profile was measured using Pentacam HR device. Paired t test was used to compare preoperative and postoperative values. Spearman correlation analysis was performed to evaluate the relationship between the central corneal thickness changes and attempted spherical equivalent refraction (SER). Results: The mean uncorrected distance visual acuity significantly improved after surgery (P<0.001). Significant differences in central, midperipheral, ablative annular, and peripheral corneal thicknesses were observed from preoperatively to 6 months postoperatively (all P<0.001). There was no significant correlation between the changes in the central corneal thickness and attempted SER (P=0.23). Conclusions: The corneal thicknesses across the whole ablation zone including central corneal thickness, significantly decrease postoperatively compared with preoperatively.
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Corneal epithelial thickness measured by Fourier-domain optical coherence tomography. SPEKTRUM DER AUGENHEILKUNDE 2015. [DOI: 10.1007/s00717-015-0267-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
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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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Chen X, Stojanovic A, Liu Y, Chen Y, Zhou Y, Utheim TP. Postoperative Changes in Corneal Epithelial and Stromal Thickness Profiles After Photorefractive Keratectomy in Treatment of Myopia. J Refract Surg 2015; 31:446-53. [DOI: 10.3928/1081597x-20150623-02] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2014] [Accepted: 05/20/2015] [Indexed: 11/20/2022]
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Xu Z, Shen M, Hu L, Zhuang X, Peng M, Hu D, Liu J, Wang J, Qu J, Lu F. The Impact of Flap Creation Methods for Sub-Bowman's Keratomileusis (SBK) on the Central Thickness of Bowman's Layer. PLoS One 2015; 10:e0124996. [PMID: 25938492 PMCID: PMC4418749 DOI: 10.1371/journal.pone.0124996] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2014] [Accepted: 03/19/2015] [Indexed: 11/20/2022] Open
Abstract
Purpose To determine the impact of flap creation methods for sub-Bowman’s keratomileusis (SBK) on central Bowman’s layer thickness. Methods SBK flaps were made by Moria microkeratome for 20 subjects and by femtosecond (FEMTO) laser for 21 subjects. Corneal sublayer thicknesses were measured by ultra-high resolution optical coherence tomography before SBK and at 1 day, 1 week, 2 weeks, and 1 month afterwards. Each subject was imaged twice on each visit. Thicknesses of central epithelium, Bowman’s layer, flap, and total cornea were calculated using a custom-made automated image processing algorithm. The repeatability of sublayer thickness measurements was tested by the intraclass correlation coefficient (ICC) and by the coefficient of repeatability (CoR) at 1 week post-SBK. Results ICCs of the Moria and FEMTO groups were ≥0.959 and ≥0.961 respectively for all sublayer measurements. The segmentation CoRs were less than 6.78% and 5.63% respectively. For both groups, microdistortions were present in the epithelium and Bowman’s layer after SKB. The flap thickness of the Moria group was 9.8 μm (95% confidence interval: 4.8 – 14.8μm) thinner than the FEMTO group one day after SBK (independent samples t-test, P < 0.05). Bowman’s layer became thicker by 1.6 ± 1.1 μm and 1.7 ± 1.6 μm one day post-SBK for the Moria and FEMTO groups (repeated ANOVA, P < 0.05) and then remained stable. Corneal and sublayer thickness were similar between the two groups. Conclusions Central Bowman’s layer thickness increased 1 day post-SBK. Flap creation by Moria microkeratome and femtosecond laser did not have significantly different impacts on Bowman’s layer thickness following SBK. Trial Registration Chinese Clinical Trial Registry (ChiCTR) NO: ChiCTR-OCH-14004525
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Affiliation(s)
- Zhe Xu
- School of Ophthalmology and Optometry, Wenzhou Medical University, Wenzhou, Zhejiang, China
| | - Meixiao Shen
- School of Ophthalmology and Optometry, Wenzhou Medical University, Wenzhou, Zhejiang, China
| | - Liang Hu
- School of Ophthalmology and Optometry, Wenzhou Medical University, Wenzhou, Zhejiang, China
| | - Xiran Zhuang
- School of Ophthalmology and Optometry, Wenzhou Medical University, Wenzhou, Zhejiang, China
| | - Mei Peng
- School of Ophthalmology and Optometry, Wenzhou Medical University, Wenzhou, Zhejiang, China
| | - Di Hu
- School of Ophthalmology and Optometry, Wenzhou Medical University, Wenzhou, Zhejiang, China
| | - Jing Liu
- School of Ophthalmology and Optometry, Wenzhou Medical University, Wenzhou, Zhejiang, China
| | - Jianhua Wang
- Department of Ophthalmology, Bascom Palmer Eye Institute, University of Miami, Miami, FL, United States of America
| | - Jia Qu
- School of Ophthalmology and Optometry, Wenzhou Medical University, Wenzhou, Zhejiang, China
| | - Fan Lu
- School of Ophthalmology and Optometry, Wenzhou Medical University, Wenzhou, Zhejiang, China
- * E-mail:
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Corneal Epithelial Remodeling after LASIK Measured by Fourier-Domain Optical Coherence Tomography. J Ophthalmol 2015; 2015:860313. [PMID: 26060579 PMCID: PMC4427820 DOI: 10.1155/2015/860313] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2015] [Revised: 04/09/2015] [Accepted: 04/13/2015] [Indexed: 11/17/2022] Open
Abstract
Purpose. To quantify corneal epithelial thickness changes after myopic LASIK by OCT. Methods. Epithelial thickness before and after myopic LASIK were measured by a Fourier-domain OCT system. Average central (within 1 mm diameter) and paracentral epithelial thickness (5~6 mm diameter) before and after LASIK were compared. Correlation between central epithelial thickness change and laser spherical equivalent setting was evaluated. An epithelial smoothing constant was estimated based on a mathematical model published previously. Results. Nineteen eyes from 11 subjects were included in the study. Eyes had myopic LASIK ranging from -1.69 D to -6.75 D spherical equivalent. The average central epithelial thickness was 52.6 ± 4.1 μm before LASIK and 56.2 ± 4.3 μm 3 months after LASIK (p = 0.002). The average paracentral epithelial thickness was 51.6 ± 6.6 μm before LASIK and 54.8 ± 4.3 μm 3 months after LASIK (p = 0.007). The change in average central epithelial thickness was correlated with laser spherical equivalent (R (2) = 0.40, p = 0.028). The epithelial smoothing constant was estimated to be 0.46 mm. Conclusions. Corneal epithelial thickens centrally and paracentrally after myopic LASIK. The extent of epithelial remodeling correlated with the amount of LASIK correction and could be predicted by a mathematical model.
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[Corneal morphometric predictive models from ametropia to excimer laser treatment]. ACTA ACUST UNITED AC 2015; 90:312-23. [PMID: 25865651 DOI: 10.1016/j.oftal.2014.09.012] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2013] [Revised: 09/09/2014] [Accepted: 09/30/2014] [Indexed: 11/23/2022]
Abstract
OBJECTIVE To develop corneal morphometric models with refractive error in excimer laser surgery. METHOD A prospective-longitudinal study was conducted on 78 patients (151 eyes) using the LASIK surgical technique, and 56 patients (111 eyes) with myopic astigmatism using ESIRIS (Schwind-Germany) equipment with pendulous microkeratome. The results were analyzed using descriptive statistics. A NIDEK Confoscan microscope was used to obtain and study the images. RESULTS After LASIK treatment 84.3% of the variations in epithelium thickness variations were due to the magnitude of refractive error and the epithelium thickness before LASIK treatment. More than two-thirds (68.8%) of the variations in keratocyte density variations in posterior flap and 48.2% of the variations in the anterior retroablation zone were due to the magnitude of the refractive error. Variations of 90% were found in the corneal thickness after LASEK, which were due to the magnitude of the refractive error before LASEK. CONCLUSIONS Predictive models reveal that morphometrical variations depend of the magnitude of the refractive error. These models are very important in the selection of patient for refractive surgery, and also for the specific technique to use.
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Reinstein DZ, Gobbe M, Archer TJ, Youssefi G, Sutton HFS. Stromal surface topography-guided custom ablation as a repair tool for corneal irregular astigmatism. J Refract Surg 2015; 31:54-9. [PMID: 25599543 DOI: 10.3928/1081597x-20141218-06] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2014] [Accepted: 09/26/2014] [Indexed: 11/20/2022]
Abstract
PURPOSE To illustrate the concept of using a stromal surface topography-guided procedure for therapeutic repair after a complication following primary laser refractive surgery. METHODS One case example of therapeutic retreatment for short nasal flap after primary LASIK performed in September 2000 is presented. The Artemis very high-frequency digital ultrasound arc-scanner (Arc-Scan, Inc., Morrison, CO) was used to obtain layered corneal thickness including epithelial thickness profile. Corneal front surface elevation was measured with the Orbscan II (Bausch & Lomb, Salt Lake City, UT). Stromal surface height was then calculated by subtracting epithelial thickness data from corneal front surface elevation data and used to calculate the ablation profile applied to the eye. The treatment was performed using the Ultralink system (ArcScan, Inc.), linking the ultrasound corneal thickness data with the Technolas 217c laser (Bausch & Lomb). Postoperative data were available at 30 days and 13 years. RESULTS One month after treatment, the epithelial thickness map demonstrated that the difference in thickness between the thinnest and thickest points located 2.5-mm nasally was reduced by 26 µm (from 56 to 30 µm). The axial difference map demonstrated an increase in corneal curvature of approximately 4 diopters where the cornea was the flattest nasally, thereby reducing the corneal asymmetry. The anterior elevation map also showed a reduced depression nasally. The patient reported significant improvement of her night vision. CONCLUSIONS This case example of stromal surface topography-guided treatment demonstrated a significant reduction in the irregularity of the stromal surface and an improvement in the topography, and the visual quality. Stromal surface topography-guided ablation might become the tool of the future for therapeutic repairs because it offers advantages over the current alternative of transepithelial phototherapeutic keratectomy.
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Vestergaard AH, Grauslund J, Ivarsen AR, Hjortdal JØ. Central corneal sublayer pachymetry and biomechanical properties after refractive femtosecond lenticule extraction. J Refract Surg 2014; 30:102-8. [PMID: 24763475 DOI: 10.3928/1081597x-20140120-05] [Citation(s) in RCA: 52] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2013] [Accepted: 10/24/2013] [Indexed: 11/20/2022]
Abstract
PURPOSE To compare central corneal sublayer pachymetry and biomechanical properties after femtosecond lenticule extraction (FLEX) and small-incision lenticule extraction (SMILE). METHODS A prospective, randomized, single-masked clinical trial of 35 patients treated for moderate to high myopia with FLEX in one eye and SMILE in the other. Anterior segment optical coherence tomography imaging (Heidelberg Spectralis; Heidelberg Engineering GmbH, Heidelberg, Germany) was used to measure central corneal thickness (CCT) and epithelial, flap/cap, and residual stromal bed thickness centrally. The Ocular Response Analyzer (Reichert Ophthalmic Instruments, Buffalo, NY) was used to assess corneal hysteresis (CH) and corneal resistance factor (CRF). Patients were examined before and 6 months after surgery. RESULTS Mean decrease in CCT was 105 μm in FLEX-treated eyes and 106 μm in SMILE-treated eyes (P = .70), which is equivalent to approximately 14 μm/diopters corrected. Mean central epithelial thickness increased 7 ± 6 μm in FLEX-treated eyes and 6 ± 5 μm in SMILE-treated eyes (P = .64). Achieved mean flap/cap thickness was 4 ± 6 μm from the expected thickness in FLEX-treated eyes and 4 ± 9 μm in SMILE-treated eyes (P = .37). CH was reduced 2.7 ± 1.3 mm Hg in FLEX-treated eyes and 3.3 ± 1.2 mm Hg in SMILE-treated eyes (P = .08). CRF was reduced 4.5 ± 1.2 mm Hg in FLEX-treated eyes and 4.6 ± 1.2 mm Hg in SMILE-treated eyes (P = .71). CH and CRF were highly correlated with CCT, but not patient age. CONCLUSIONS In this paired-eye study, the flap-based FLEX and cap-based SMILE resulted in almost identical changes in central corneal sublayer pachymetry and biomechanical properties for moderate to high myopia 6 months after treatment.
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Ivarsen A, Hjortdal J. All-Femtosecond Laser Keratorefractive Surgery. CURRENT OPHTHALMOLOGY REPORTS 2014. [DOI: 10.1007/s40135-013-0032-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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Vestergaard AH. Past and present of corneal refractive surgery: a retrospective study of long-term results after photorefractive keratectomy and a prospective study of refractive lenticule extraction. Acta Ophthalmol 2014; 92 Thesis 2:1-21. [PMID: 24636364 DOI: 10.1111/aos.12385] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
UNLABELLED Surgical correction of refractive errors is becoming increasingly popular. In the 1990s, the excimer laser revolutionized the field of corneal refractive surgery with PRK and LASIK, and lately refractive lenticule extraction (ReLEx) of intracorneal tissue, using only a femtosecond laser, has become possible. Two new procedures were developed, ReLEx flex (FLEX) and ReLEx smile (SMILE). Until this thesis, only a few long-term studies of PRK with a relatively limited number of patients had been published; therefore, this thesis intended to retrospectively evaluate long-term outcomes after PRK for all degrees of myopia for a large number of patients. Furthermore, a prospective contralateral eye study comparing FLEX and SMILE, when treating high to moderate degrees of myopia, had not been performed prior to this study. This was the second aim of this thesis. In the first study, results from 160 PRK patients (289 eyes) were presented. Preoperative spherical equivalent ranged from -1.25 to -20.25 D, with 78% having low myopia (<-6 D). Average follow-up time was 16 years (range 13-19 years), making this the longest published follow-up study on PRK patients. Outcomes from eyes with low myopia were generally superior to outcomes from eyes with high myopia, at final follow-up. Seventy-two percent were within ± 1.00 D of target refraction, as compared to 47% of eyes with high myopia. However, results from a subgroup of unilateral treated PRK patients indicated that refraction at final follow-up was affected by myopic progression. Fifty percent of eyes with low myopia had uncorrected 20/20 distance visual acuity or better, as compared to 22% of eyes with high myopia. Haze did not occur if attempted corrections were <-4 D, and only eyes with high myopia lost two lines or more of CDVA (corrected distance visual acuity). Eighty-one per cent were satisfied or very satisfied with their surgery. CONCLUSION The results support the continued use of the excimer laser for corneal surface ablation as a treatment option for correction of low degrees of myopia, and as the treatment of choice for subgroups of refractive patients (thin corneas, etc.). The results also highlight that treatment of higher degrees of myopia with standard PRK should only be done today under special circumstances, due to low refractive predictability, and high risk of corneal haze. Technological advances since then should be taken into account when comparing these results with contemporary techniques. In the second study, 35 patients were randomized to receive FLEX in one eye and SMILE in the other. Preoperative spherical equivalent refraction ranged from -6 to -10 D with low degrees of astigmatism. A total of 34 patients completed the 6 month follow-up period. Refractive and visual outcomes were very similar for the two methods, as well as tear film measurements and changes in corneal biomechanics. Ninety-seven percent were within ± 1.00 D of target refraction, no eyes lost two lines or more of CDVA, and contrast sensitivity was unaffected after both procedures. The changes in higher-order aberrations were also very similar. There were also no differences in tear film parameters 6 months after surgery, although less postoperative foreign body sensation was reported within the first week after surgery in SMILE eyes. Corneal sublayer pachymetry measurements demonstrated equally increased epithelial thickness 6 months after surgery. Contrary to expectations, it was not possible to measure the theoretical biomechanical advantages of a small corneal incision in SMILE as compared to a corneal flap in FLEX. The main differences between FLEX and SMILE were found when the corneal nerves and intraoperative complications were evaluated. Thus, corneal sensitivity was better preserved and corneal nerve morphology was less affected after SMILE, but intraoperative complications occurred more frequently, although without visual sequela. Finally, 97% were satisfied or very satisfied with both their surgeries. CONCLUSION The results support the continued use of both FLEX and SMILE for treatment of up to high degrees of myopia. Overall, refractive and visual results for both procedures were good and similar, but from a biological point of view, the less invasive SMILE technique is more attractive, as demonstrated in this study, despite being slightly more surgically demanding than FLEX.
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Affiliation(s)
- Anders Højslet Vestergaard
- Faculty of Health Science; University of Southern Denmark; Odense Denmark
- Department of Ophthalmology; Odense University Hospital; Odense Denmark
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Kim Y, Lee D, Kyung H. Comparison of LASIK Mode Ablation and PRK Mode Ablation in LASEK Using MEL-80 Excimer Laser. JOURNAL OF THE KOREAN OPHTHALMOLOGICAL SOCIETY 2014. [DOI: 10.3341/jkos.2014.55.11.1625] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Affiliation(s)
- Youngdon Kim
- Department of Ophthalmology, National Medical Center, Seoul, Korea
| | | | - Haksu Kyung
- Department of Ophthalmology, National Medical Center, Seoul, Korea
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Tay E, Li X, Gimbel HV, Kaye G. Assessment of axial length before and after myopic LASIK with the IOLMaster. J Refract Surg 2013; 29:838-41. [PMID: 24088060 DOI: 10.3928/1081597x-20130924-01] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2013] [Accepted: 06/25/2013] [Indexed: 11/20/2022]
Abstract
PURPOSE To assess the relationship between theoretical ablation depth and axial length change after LASIK with the IOLMaster (Carl Zeiss Meditec, Dublin, CA). METHODS Ninety-nine eyes were examined preoperatively and 1 and 3 months after LASIK. RESULTS Mean ± standard deviation (SD) spherical equivalent before LASIK was -4.06 ± 1.91 diopters (D). Mean ± SD ablation depth was 83.13 ± 30.31 μm. Mean ± SD postoperative axial length of 25.11 ± 0.14 mm at 1 month was significantly shorter than mean ± SD preoperative axial length of 25.20 ± 0.14 mm (P < .001) with no subsequent change thereafter (P = .450). An increase in ablation depth of 1 μm led to a decrease in axial length of 0.00118 ± 0.00005 mm. Ablation depth correlated strongly with change in axial length (adjusted R(2) = 0.9039). CONCLUSIONS The IOLMaster showed a decrease in axial length after LASIK that correlated well with theoretical ablation depth.
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Benayoun Y, Rosenberg R, Casse G, Dallaudière B, Robert PY. [Imaging and quantification of corneal neovascularization]. J Fr Ophtalmol 2013; 36:693-703. [PMID: 23969009 DOI: 10.1016/j.jfo.2013.04.006] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2013] [Revised: 04/09/2013] [Accepted: 04/23/2013] [Indexed: 11/27/2022]
Abstract
Corneal neovascularization is defined as the invasion of vessels into the normally avascular clear corneal stroma, secondary to acute or chronic tissue injury. In addition to decreasing visual acuity, vascularity introduces circulating immune cells, reducing corneal immune privilege and the graft survival of subsequent keratoplasty. Thus, reducing neovascularization has become a recent therapeutic target in order to increase the success of corneal transplantation. Comparing the effects of antiangiogenic drugs assumes that we are able to quantify corneal neovascularization before and after treatment. In the first part of this literature review, we present the various methods to document neovessels (color photos, fluorescein and indocyanine green anterior segment angiography, in vivo confocal microscopy). Next, we report methods to classify and quantify corneal neovascularization.
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Affiliation(s)
- Y Benayoun
- Service d'ophtalmologie, hôpital Dupuytren, CHU de Limoges, 2, avenue Martin-Luther-King, 87042 Limoges cedex 1, France; Service d'ophtalmologie, clinique François-Chénieux, 18, rue du Général-Catroux, 87039 Limoges cedex, France.
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Improving Interobserver Variation in Corneal Sublayer Pachymetry Using ConfoScan4 With Z Ring. Eye Contact Lens 2013; 39:214-9. [DOI: 10.1097/icl.0b013e318286bc35] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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Arba Mosquera S, Awwad ST. Theoretical analyses of the refractive implications of transepithelial PRK ablations. Br J Ophthalmol 2013; 97:905-11. [PMID: 23603760 DOI: 10.1136/bjophthalmol-2012-302853] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Abstract
BACKGROUND/AIMS To analyse the refractive implications of single-step, transepithelial photorefractive keratectomy (TransPRK) ablations. METHODS A simulation for quantifying the refractive implications of TransPRK ablations has been developed. The simulation includes a simple modelling of corneal epithelial profiles, epithelial ablation profiles as well as refractive ablation profiles, and allows the analytical quantification of the refractive implications of TransPRK in terms of wasted tissue, achieved optical zone (OZ) and induced refractive error. RESULTS Wasted tissue occurs whenever the actual corneal epithelial profile is thinner than the applied epithelial ablation profile, achieved OZ is reduced whenever the actual corneal epithelial profile is thicker than the applied epithelial ablation profile and additional refractive errors are induced whenever the actual difference centre-to-periphery in the corneal epithelial profile deviates from the difference in the applied epithelial ablation profile. CONCLUSIONS The refractive implications of TransPRK ablations can be quantified using simple theoretical simulations. These implications can be wasted tissue (∼14 µm, if the corneal epithelial profile is thinner than the ablated one), reduced OZ (if the corneal epithelial profile is thicker than ablated one, very severe for low corrections) and additional refractive errors (∼0.66 D, if the centre-to-periphery progression of the corneal epithelial profile deviates from the progression of the ablated one). When TransPRK profiles are applied to normal, not previously treated, non-pathologic corneas, no specific refractive implications associated to the transepithelial profile can be anticipated; TransPRK would provide refractive outcomes equal to those of standard PRK. Adjustments for the planned OZ and, in the event of retreatments, for the target sphere can be easily derived.
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Affiliation(s)
- Samuel Arba Mosquera
- Department of Research and Development, SCHWIND eye-tech-solutions, Kleinostheim, Germany.
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Klingler KN, McLaren JW, Bourne WM, Patel SV. Corneal endothelial cell changes 5 years after laser in situ keratomileusis: femtosecond laser versus mechanical microkeratome. J Cataract Refract Surg 2012; 38:2125-30. [PMID: 23073480 DOI: 10.1016/j.jcrs.2012.07.034] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2012] [Revised: 07/24/2012] [Accepted: 07/27/2012] [Indexed: 10/27/2022]
Abstract
PURPOSE To compare corneal endothelial cell density (ECD) and morphology between flap creation with a femtosecond laser and flap creation with a mechanical microkeratome 5 years after laser in situ keratomileusis (LASIK). SETTING Mayo Clinic, Rochester, Minnesota, USA. DESIGN Prospective randomized masked paired-eye study. METHODS In this study of LASIK for myopia or myopic astigmatism, fellow eyes were randomized by ocular dominance to flap creation by a femtosecond laser or by a mechanical microkeratome. Central endothelial images were analyzed before and 3 years and 5 years after LASIK; endothelial cell variables were compared between treatments at each examination. Relationships between endothelial cell loss and contact lens wear, residual bed thickness, and preoperative refractive error were evaluated. RESULTS There were no differences in the ECD, percentage of hexagonal cells, or coefficient of variation of cell area between treatments at any examination (all P = .99); the smallest detectable differences were 120 cells/mm(2), 5%, and 2%, respectively. The mean annual rate of corneal endothelial cell loss was -0.1% ± 1.2% (SD) and -0.1% ± 1.0% for the femtosecond laser and the mechanical microkeratome, respectively. Endothelial cell loss was not associated with contact lens wear, residual bed thickness, or preoperative refractive error. CONCLUSIONS The energy delivered to the cornea during femtosecond laser flap creation did not affect the corneal endothelium 5 years after LASIK when compared with flap creation with a mechanical microkeratome. Corneas that have had either method of flap creation could be accepted as donor tissue for endothelial keratoplasty from the standpoint of endothelial health. FINANCIAL DISCLOSURE No author has a financial or proprietary interest in any material or method mentioned.
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Affiliation(s)
- Kyle N Klingler
- Department of Ophthalmology, Mayo Clinic, Rochester, Minnesota, USA
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Li Y, Tan O, Brass R, Weiss JL, Huang D. Corneal epithelial thickness mapping by Fourier-domain optical coherence tomography in normal and keratoconic eyes. Ophthalmology 2012; 119:2425-33. [PMID: 22917888 DOI: 10.1016/j.ophtha.2012.06.023] [Citation(s) in RCA: 243] [Impact Index Per Article: 20.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2011] [Revised: 06/13/2012] [Accepted: 06/14/2012] [Indexed: 02/08/2023] Open
Abstract
OBJECTIVE To map the corneal epithelial thickness with Fourier-domain optical coherence tomography (OCT) and to develop epithelial thickness-based variables for keratoconus detection. DESIGN Cross-sectional observational study. PARTICIPANTS One hundred forty-five eyes from 76 normal subjects and 35 keratoconic eyes from 22 patients. METHODS A 26,000-Hz Fourier-domain OCT system with 5-μm axial resolution was used. The cornea was imaged with a Pachymetry + Cpwr scan pattern (6-mm scan diameter, 8 radials, 1024 axial-scans each, repeated 5 times) centered on the pupil. Three scans were obtained at a single visit in a prospective study. A computer algorithm was developed to map the corneal epithelial thickness automatically. Zonal epithelial thicknesses and 5 diagnostic variables, including minimum, superior-inferior (S-I), minimum-maximum (MIN-MAX), map standard deviation (MSD), and pattern standard deviation (PSD), were calculated. Repeatability of the measurements was assessed by the pooled standard deviation. The area under the receiver operating characteristic curve (AUC) was used to evaluate diagnostic accuracy. MAIN OUTCOME MEASURES Descriptive statistics, repeatability, and AUC of the zonal epithelial thickness and diagnostic variables. RESULTS The central, superior, and inferior epithelial thickness averages were 52.3 ± 3.6 μm, 49.6 ± 3.5 μm, and 51.2 ± 3.4 μm in normal eyes and 51.9 ± 5.3 μm, 51.2 ± 4.2 μm, and 49.1 ± 4.3 μm in keratoconic eyes. Compared with normal eyes, keratoconic eyes had significantly lower inferior (P = 0.03) and minimum (P<0.0001) corneal epithelial thickness, greater S-I (P = 0.013), more negative MIN-MAX (P<0.0001), greater MSD (P<0.0001), and larger PSD (P<0.0001). The repeatability of the zonal average, minimum, S-I, and MIN-MAX epithelial thickness variables were between 0.7 and 1.9 μm. The repeatability of MSD was better than 0.4 μm. The repeatability of PSD was 0.02 or better. Among all epithelial thickness-based variables investigated, PSD provided the best diagnostic power (AUC = 1.00). Using an PSD cutoff value of 0.057 alone gave 100% specificity and 100% sensitivity. CONCLUSIONS High-resolution Fourier-domain OCT mapped corneal epithelial thickness with good repeatability in both normal and keratoconic eyes. Keratoconus was characterized by apical epithelial thinning. The resulting deviation from the normal epithelial pattern could be detected with very high accuracy using the PSD variable. FINANCIAL DISCLOSURE(S) Proprietary or commercial disclosure may be found after the references.
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Affiliation(s)
- Yan Li
- Center for Ophthalmic Optics and Lasers, Casey Eye Institute and Department of Ophthalmology, Oregon Health and Science University, Portland, Oregon 97239, USA.
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Luger MH, Ewering T, Arba-Mosquera S. Consecutive myopia correction with transepithelial versus alcohol-assisted photorefractive keratectomy in contralateral eyes: One-year results. J Cataract Refract Surg 2012; 38:1414-23. [DOI: 10.1016/j.jcrs.2012.03.028] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2012] [Revised: 03/02/2012] [Accepted: 03/12/2012] [Indexed: 10/28/2022]
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Flap thickness in eyes with ectasia after laser in situ keratomileusis. J Cataract Refract Surg 2012; 38:752-7. [PMID: 22424807 DOI: 10.1016/j.jcrs.2011.11.044] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2011] [Revised: 11/15/2011] [Accepted: 11/20/2011] [Indexed: 11/24/2022]
Abstract
PURPOSE To measure central flap thickness in eyes with ectasia after laser in situ keratomileusis (LASIK) and to compare these values with estimated anticipated flap thickness based on mean published values for each device used for flap creation. SETTING Emory Vision at Emory University, Atlanta, Georgia, USA. DESIGN Retrospective comparative case series, using published data for controls. METHODS Confocal microscopic analysis was performed using the Confoscan 3 device to measure central flap thickness in eyes with ectasia after LASIK. Pre-LASIK records were evaluated for information, including basic patient demographics, preoperative corneal topographies, estimated anticipated flap thickness based on the mean average thickness values, and residual stromal bed (RSB) thickness calculations using measured and estimated flap thicknesses. RESULTS Fifty eyes of 29 patients were evaluated. The mean measured flap thickness was 138 μm ± 26 (SD) (range 90 to 220 μm). There were no significant differences between measured and estimated flap thicknesses (138 μm versus 135 μm; P=.5) or RSB thickness (329 μm versus 332 μm; P=.7), nor were there differences in flap thickness between eyes developing ectasia with normal corneal topographies and eyes with abnormal corneal topographies. One eye had a measured flap resulting in an unintended RSB thickness less than 250 μm; this eye also had abnormal topography. CONCLUSIONS Measured central flap thickness was not thicker than estimated in most eyes developing ectasia after LASIK. Thus, excessively thick flaps do not appear to be a major contributing factor to the pathogenesis of ectasia after LASIK. FINANCIAL DISCLOSURE No author has a financial or proprietary interest in any material or method mentioned.
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Reinstein DZ, Archer TJ, Gobbe M. Change in Epithelial Thickness Profile 24 Hours and Longitudinally for 1 Year After Myopic LASIK: Three-dimensional Display With Artemis Very High-frequency Digital Ultrasound. J Refract Surg 2012; 28:195-201. [DOI: 10.3928/1081597x-20120127-02] [Citation(s) in RCA: 84] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2011] [Accepted: 11/28/2011] [Indexed: 11/20/2022]
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