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Sy ME, Kovoor TA, Tannan A, Choi D, Deng SX, Danesh J, Hamilton DR. Combined astigmatic keratotomy and conductive keratoplasty to correct high corneal astigmatism. J Cataract Refract Surg 2015; 41:1050-6. [PMID: 25935339 DOI: 10.1016/j.jcrs.2014.10.028] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2014] [Revised: 09/14/2014] [Accepted: 10/11/2014] [Indexed: 12/01/2022]
Abstract
PURPOSE To determine the safety, efficacy, and predictability of combined astigmatic keratotomy (AK) and conductive keratoplasty (CK) for treating high corneal astigmatism. SETTING University of California-Los Angeles, Los Angeles, California, USA. DESIGN Retrospective case series. METHODS From January 1, 2004, to December 31, 2009, AK and CK were performed in eyes with corneal astigmatism of 5.0 diopters (D) or more after keratoplasty or trauma. The uncorrected (UDVA) and corrected (CDVA) distance visual acuities, spherical equivalent (SE), defocus equivalent, mean astigmatism, efficacy index, and complications were evaluated. RESULTS In 11 eyes of 11 patients, the mean UDVA improved from 1.54 logMAR ± 0.50 (SD) preoperatively to 0.69 ± 0.62 logMAR 3 months postoperatively (P < .001) and the mean CDVA from 0.55 ± 0.62 logMAR to 0.12 ± 0.11 logMAR (P = .028). The mean SE and mean defocus equivalent decreased from -1.25 ± 5.06 D to 3.13 ± 3.06 D (P = .15) and from 7.98 ± 4.41 D to 6.97 ± 3.73 D (P = .45), respectively; these changes were not statistically significant. The mean absolute astigmatism decreased from 10.25 ± 4.71 D to 4.31 ± 2.34 D (P < .001). The mean absolute orthogonal and mean oblique astigmatism showed a statistically significant decrease. The efficacy index was 0.82. One case of wound gape after AK required suturing. No infectious keratitis, corneal perforation, or graft rejection occurred. CONCLUSIONS Results indicate that combined AK and CK is safe and effective for correcting high corneal astigmatism after surgery or trauma.
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Affiliation(s)
- Mary Ellen Sy
- From the American Eye Center (Sy), Makati, Manila, Philippines; Houston Eye Associates (Kovoor), Houston, Texas, Jules Stein Eye Institute (Tannan, Deng, Hamilton), David Geffen School of Medicine (Danesh), University of California Los Angeles, Los Angeles, and the Department of Ophthalmology (Choi), Stanford School of Medicine, Stanford, California, USA
| | - Timmy A Kovoor
- From the American Eye Center (Sy), Makati, Manila, Philippines; Houston Eye Associates (Kovoor), Houston, Texas, Jules Stein Eye Institute (Tannan, Deng, Hamilton), David Geffen School of Medicine (Danesh), University of California Los Angeles, Los Angeles, and the Department of Ophthalmology (Choi), Stanford School of Medicine, Stanford, California, USA
| | - Anjali Tannan
- From the American Eye Center (Sy), Makati, Manila, Philippines; Houston Eye Associates (Kovoor), Houston, Texas, Jules Stein Eye Institute (Tannan, Deng, Hamilton), David Geffen School of Medicine (Danesh), University of California Los Angeles, Los Angeles, and the Department of Ophthalmology (Choi), Stanford School of Medicine, Stanford, California, USA
| | - Daniel Choi
- From the American Eye Center (Sy), Makati, Manila, Philippines; Houston Eye Associates (Kovoor), Houston, Texas, Jules Stein Eye Institute (Tannan, Deng, Hamilton), David Geffen School of Medicine (Danesh), University of California Los Angeles, Los Angeles, and the Department of Ophthalmology (Choi), Stanford School of Medicine, Stanford, California, USA
| | - Sophie X Deng
- From the American Eye Center (Sy), Makati, Manila, Philippines; Houston Eye Associates (Kovoor), Houston, Texas, Jules Stein Eye Institute (Tannan, Deng, Hamilton), David Geffen School of Medicine (Danesh), University of California Los Angeles, Los Angeles, and the Department of Ophthalmology (Choi), Stanford School of Medicine, Stanford, California, USA
| | - Jennifer Danesh
- From the American Eye Center (Sy), Makati, Manila, Philippines; Houston Eye Associates (Kovoor), Houston, Texas, Jules Stein Eye Institute (Tannan, Deng, Hamilton), David Geffen School of Medicine (Danesh), University of California Los Angeles, Los Angeles, and the Department of Ophthalmology (Choi), Stanford School of Medicine, Stanford, California, USA
| | - D Rex Hamilton
- From the American Eye Center (Sy), Makati, Manila, Philippines; Houston Eye Associates (Kovoor), Houston, Texas, Jules Stein Eye Institute (Tannan, Deng, Hamilton), David Geffen School of Medicine (Danesh), University of California Los Angeles, Los Angeles, and the Department of Ophthalmology (Choi), Stanford School of Medicine, Stanford, California, USA.
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Ye P, Xu W, Tang X, Yao K, Li Z, Xu H, Shi J. Conductive keratoplasty for symptomatic presbyopia following monofocal intraocular lens implantation. Clin Exp Ophthalmol 2011; 39:404-11. [PMID: 21070548 DOI: 10.1111/j.1442-9071.2010.02464.x] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Panpan Ye
- Eye Center, Second Affiliated Hospital, Zhejiang University, Hangzhou, China
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Ursea R, Feng MT. Traumatic Flap Striae 6 Years After LASIK: Case Report and Literature Review. J Refract Surg 2010; 26:899-905. [DOI: 10.3928/1081597x-20091209-02] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 08/30/2023]
Abstract
Purpose:
To report a case of traumatic flap striae without flap dislocation 6 years after LASIK and provide a literature review of surgical flap striae, late traumatic flap striae, and their management.
Methods:
A 28-year-old man presented with late traumatic flap striae without concurrent flap dislocation, which closely approximated the longest reported interval between LASIK and the development of flap striae.
Results:
In the absence of flap dislocation, the finding of striae alone was subtle and went undetected initially. The flap was successfully refloated, stretched, and smoothed with recovery of 20/20 vision.
Conclusions:
Traumatic LASIK flap complications may occur many years after the original procedure. This report presents the first case of late traumatic flap striae without concurrent flap dislocation. Proper management can restore good visual function.
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Conductive keratoplasty followed by collagen cross-linking with riboflavin-UV-A in patients with keratoconus. Cornea 2010; 29:239-43. [PMID: 20023583 DOI: 10.1097/ico.0b013e3181a818ab] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
PURPOSE To evaluate the combined effect of conductive keratoplasty (CK) followed by corneal collagen cross-linking (CXL) in 2 patients with keratoconus. METHODS CK spots were applied on the flatter side of the cornea followed by CXL using riboflavin and UV-A light. RESULTS Immediately after CK, a significant corneal topographic improvement was observed. The CK effect regressed 3 months postoperatively and remained unchanged until the sixth postoperative month in both patients. CONCLUSION Corneal remodeling with CK in patients with keratoconus seems to have a temporary effect despite the subsequent application of CXL.
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Chang JSM, Lau SYF. Conductive keratoplasty to treat hyperopic overcorrection after LASIK for myopia. J Refract Surg 2010; 27:49-55. [PMID: 20166620 DOI: 10.3928/1081597x-20100212-10] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2009] [Accepted: 01/13/2010] [Indexed: 11/20/2022]
Abstract
PURPOSE to investigate the refractive outcomes and stability of conductive keratoplasty (CK) for retreatment of myopic LASIK overcorrection. METHODS seven eyes (six patients) that were overcorrected after myopic LASIK by +1.00 to +2.75 diopters (D) manifest refraction spherical equivalent (MRSE) were retreated using CK. All eyes had insufficient stromal thickness for LASIK retreatment. LightTouch CK was performed at least 1 year after LASIK. Either 8 or 16 spots were applied at 7- and/or 8-mm zones on the cornea. Uncorrected distance visual acuity, manifest refraction, corrected distance visual acuity (CDVA), and postoperative complications were analyzed. RESULTS mean MRSE after CK at last follow-up was +0.38 ± 0.52 D (range: -0.38 to +1.13 D). The change in MRSE ranged from -0.63 to -2.38 D. Mean MRSE after CK changed from -0.60 ± 2.07 D (range: -3.38 to +1.50 D) at 1 week to +0.45 ± 0.69 D (range: -0.38 to +1.38 D) at 12 months. Two eyes experienced an initial overcorrection of -2.75 D and -3.38 D, respectively, at 1 week after CK. Cylinder ≤0.75 D was induced in four eyes, whereas one eye had a 0.75-D reduction in cylinder. All eyes had CDVA of logMAR 0.10 or better. Two eyes lost one line of CDVA and no eyes lost more than one line. CONCLUSIONS lighttouch CK retreatment for over-corrected myopic LASIK can reduce the hyperopia but produces minimal change in cylinder, and may be appropriate for eyes with insufficient stromal tissue for repeated excimer laser surgery. Early regression occurs commonly.
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Affiliation(s)
- John S M Chang
- Guy Hugh Chan Refractive Surgery Centre, Department of Ophthalmology, Hong Kong Sonatorium and Hospital, Happy Valley, Hong Kong.
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Conductive Keratoplasty for the Treatment of Astigmatism Induced by CornealTrauma or Incision. J Refract Surg 2010; 26:33-42. [DOI: 10.3928/1081597x-20101215-05] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2008] [Accepted: 12/16/2008] [Indexed: 11/20/2022]
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Wang TJ, Lo W, Hsueh CM, Hsieh MS, Dong CY, Hu FR. Ex vivo multiphoton analysis of rabbit corneal wound healing following conductive keratoplasty. JOURNAL OF BIOMEDICAL OPTICS 2008; 13:034019. [PMID: 18601564 DOI: 10.1117/1.2943156] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/16/2023]
Abstract
Ex vivo multiphoton imaging is used to characterize rabbit corneal wound healing after conductive keratoplasty (CK) procedures. CK is performed on the right eyes from eight New Zealand albino rabbits while the left eyes are punctured by a keratoplast tip without energy application. Rabbits are humanely sacrificed 1 day, 1, 2, and 4 weeks after the CK procedure. Eye balls are enucleated and placed on the microscope for multiphoton imaging. Multiphoton imaging reveals damage of corneal epithelium and stroma caused by the CK procedure and the subsequent wound healing process can be followed without histological procedures. Multiphoton excited autofluorescence images demonstrate that re-epithelilialization is accomplished within 1 week in both CK and control groups. However, epithelial hyperplasia is observed in CK corneas. In addition, stromal wounds in the control group become inconspicuous within 1 week while obvious wounds still exist in CK corneas for at least 4 weeks. Postconductive keratoplasty corneal damage and wound healing can be characterized by multiphoton microscopy without histological procedures. Our results suggest that multiphoton microscopy has potential in the clinical evaluation of corneal damage due to refractive surgery, and can be used to study and reduce the unwanted side effects of these procedures.
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Affiliation(s)
- Tsung-Jen Wang
- Taipei Medical University Hospital, Department of Ophthalmology, Taipei 110, Taiwan
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Berjano EJ, Navarro E, Ribera V, Gorris J, Alió JL. Radiofrequency heating of the cornea: an engineering review of electrodes and applicators. Open Biomed Eng J 2007; 1:71-6. [PMID: 19662131 PMCID: PMC2701077 DOI: 10.2174/1874120700701010071] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2007] [Revised: 11/26/2007] [Accepted: 11/27/2007] [Indexed: 11/23/2022] Open
Abstract
This paper reviews the different applicators and electrodes employed to create localized heating in the cornea by means of the application of radiofrequency (RF) currents. Thermokeratoplasty (TKP) is probably the best known of these techniques and is based on the principle that heating corneal tissue (particularly the central part of the corneal tissue, i.e. the central stroma) causes collagen to shrink, and hence changes the corneal curvature. Firstly, we point out that TKP techniques are a complex challenge from the engineering point of view, due to the fact that it is necessary to create very localized heating in a precise location (central stroma), within a narrow temperature range (from 58 to 76ºC). Secondly, we describe the different applicator designs (i.e. RF electrodes) proposed and tested to date. This review is planned from a technical point of view, i.e. the technical developments are classified and described taking into consideration technical criteria, such as energy delivery mode (monopolar versus bipolar), thermal conditions (dry versus cooled electrodes), lesion pattern (focal versus circular lesions), and application placement (surface versus intrastromal).
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Affiliation(s)
- Enrique J Berjano
- Institute for Research and Innovation on Bioengineering, Technical University of Valencia, Valencia, Spain
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Abstract
PURPOSE OF REVIEW Conductive keratoplasty is a noninvasive, in-office procedure for the correction of hyperopia, hyperopic astigmatism, and management of presbyopia. It serves as an alternative to laser-based refractive surgery with essentially no intraoperative or postoperative complications. RECENT FINDINGS In the past decade, photorefractive keratectomy and laser in-situ keratomileusis have been the most popular refractive surgical procedures to correct myopia, hyperopia and astigmatism. Although relatively safe, flap-related complications often result in undesirable visual acuity. Since US Food and Drugs Administration approval in 2002, conductive keratoplasty has become a promising technique to correct low to moderate hyperopia and astigmatism. The procedure was first used by Mendez and colleagues in 1993. It is a nonlaser, no cutting procedure that delivers radio-frequency energy to corneal stroma in a circular fashion to steepen the cornea. Multiple studies have shown that conductive keratoplasty offers equal or superior efficacy, predictability, stability and safety than currently used refractive procedures to correct hyperopia or hyperopic astigmatism. In addition, monovision conductive keratoplasty has been shown to be successful for the management of presbyopia. SUMMARY Conductive keratoplasty, an alternative to the laser-based procedure, is effective, predictable, and safe to correct low to moderate hyperopia, astigmatism, and manage presbyopia.
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Affiliation(s)
- Ted T Du
- Department of Ophthalmology, Mount Sinai School of Medicine, New York, NY 10029, USA.
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Lyra JM, Trindade FC, Lyra D, Bezerra A. Outcomes of radiofrequency in advanced keratoconus. J Cataract Refract Surg 2007; 33:1288-95. [PMID: 17586389 DOI: 10.1016/j.jcrs.2007.03.042] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2006] [Accepted: 03/22/2007] [Indexed: 11/16/2022]
Abstract
PURPOSE To evaluate the use of radiofrequency energy to correct advanced keratoconus. SETTING Universidade Federal de Minas Gerais, Belo Horizonte, and Universidade de Ciências da Saúde de Alagoas, Maceió, Brazil. METHODS In this prospective comparative study, radiofrequency was applied to 25 eyes of 21 consecutive patients. One group comprised patients with a K-reading between 54.0 diopters (D) and 58.0 D; 8 thermal spots were placed at the 4.0 mm optical zone. The other group comprised patients with a K-reading greater than 58.0 D; 16 spots were applied at the 4.0 mm and 5.0 mm optical zones. The minimum follow-up was 18 months in all patients. Differences between preoperative and postoperative uncorrected visual acuity, best spectacle-corrected visual acuity (BSCVA), manifest refraction, and K-readings were clinically and statistically evaluated. RESULTS At end of the 18-month follow-up, the mean BSCVA in the 8-spot group improved from 20/100 (0.71+/-0.25 logMAR) preoperatively to 20/40 (0.32+/-0.11 logMAR) and in the 16-spot group, from 20/200 (1.03+/-0.30 logMAR) to 20/60 (0.62+/-0.22 logMAR). The mean manifest refractive spherical equivalent (MRSE) improved from -7.70 D+/-5.20 (SD) preoperatively to -6.82+/-4.41 D after 18 months in the 8-spot group and from -11.33+/-6.70 to -8.38+/-5.12 D, respectively, in the 16-spot group. The mean best contact lens-corrected visual acuity was 20/30 (0.18+/-0.24 logMAR) in the 8-spot group and 20/40 (0.31+/-0.19 logMAR) in the 16-spot group. A dense corneal scar was seen in 1 patient in the 16-spot group at the 6-month follow-up. CONCLUSIONS Radiofrequency appeared safe for the treatment of advanced keratoconus. Contact lens fitting was stable in all cases.
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Abstract
Surgical attempts to correct hyperopia have yielded varying results over the last 130 years. These techniques include the reshaping of the cornea through incisions, burns, or lamellar cuts with removal of peripheral tissue; the addition of central inlays; laser ablations; and the replacement of the crystalline lens. By examining the success of each surgical technique, the refractive surgeon may be able to make an informed decision on its indications and limitations, based on the specific patient's characteristics. Reporting the outcomes and complications of hyperopic surgery will help refine our approach to the management of an increasingly hyperopic and presbyopic population.
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Affiliation(s)
- Salomon Esquenazi
- LSU Eye Center and LSU Neuroscience Center, Louisiana State University Health Sciences Center, New Orleans, USA.
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Naoumidi TL, Kounis GA, Astyrakakis NI, Tsatsaronis DN, Pallikaris IG. Two-year follow-up of conductive keratoplasty for the treatment of hyperopic astigmatism. J Cataract Refract Surg 2006; 32:732-41. [PMID: 16765788 DOI: 10.1016/j.jcrs.2006.01.062] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2005] [Accepted: 10/13/2005] [Indexed: 11/25/2022]
Abstract
PURPOSE To evaluate the safety, efficacy, predictability, and stability of conductive keratoplasty (CK) for the treatment of hyperopic astigmatism. SETTING University of Crete Medical School, Vardinoyannion Eye Institute of Crete, Heraklion, Greece. METHODS In this prospective nonrandomized noncontrolled single-center study, 47 eyes of 34 patients (15 women and 19 men) were treated for hyperopic astigmatism (up to + 3.50 diopters [D]) with a Refractec ViewPoint CK system and followed for 24 months +/- 0.6 (SD). The treatment consisted of 4 to 36 spots applied to the periphery of the cornea. Mean age was 48.5 years +/- 9.7 years, range 25 to 68 years. All the treated eyes were analyzed for safety, efficacy, predictability, and stability. RESULTS The mean patient age was 48.5 +/- 9.7 years (range 25 to 68 years). Preoperatively, the mean manifest refraction spherical equivalent (MRSE) was +2.11 +/- 0.88 D (range -0.50 to + 4.13 D); at 12 months, it was -0.52 +/- 0.73 D and at 24 months, -0.50 +/- 0.77 D. At 24 months, the mean MRSE was within +/-0.50 D in 61% of eyes, within +/-1.00 D in 83%, and within +/-2.00 D in all eyes. At 24 months, the uncorrected visual acuity was 20/20 or better in 37% of eyes and 20/40 or better in 97%. By the end of the follow-up period, no eye had lost > or =2 Snellen lines or had an induced cylinder > or =1.50 D. CONCLUSIONS Conductive keratoplasty for low hyperopic astigmatism was a safe, effective, and stable procedure. Nomogram adjustments and careful patient selection should contribute to higher levels of predictability when treating hyperopic astigmatism.
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Affiliation(s)
- Tatiana L Naoumidi
- University of Crete Medical School, Vardinoyannion Eye Institute of Crete, Heraklion, Greece.
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Naoumidi TL, Pallikaris IG, Naoumidi II, Astyrakakis NI. Conductive keratoplasty: histological study of human corneas. Am J Ophthalmol 2005; 140:984-992. [PMID: 16376640 DOI: 10.1016/j.ajo.2005.06.027] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2005] [Revised: 06/03/2005] [Accepted: 06/11/2005] [Indexed: 10/25/2022]
Abstract
PURPOSE To determine the morphologic changes in human corneas over time following radiofrequency-based conductive keratoplasty (CK) treatment. DESIGN Prospective, observational case series. METHODS In a single-center study six human corneas of six patients with localized peripheral keratoconus underwent CK treatment followed by penetrating keratoplasty. Three spots were applied in the periphery of each cornea (6 mm optical zone). Corneal buttons were examined with light and electron microscopy at different postoperative intervals up to 6 months post-CK. RESULTS In samples assessed on day one post-CK, small areas of detachment between the basal layer of epithelial cells and Bowman's layer were observed. At 1 week after the CK procedure, the epithelium appeared almost normal. Endothelium and Descemet's membrane had no alterations. In all samples, thermally induced misconfiguration of collagen fibers, described as "crumpled" changes of collagen layers, was observed reaching 75% to 80% of the stromal depth. The area of alterations had a cylindrical shape with a diameter of 120 mum. CONCLUSIONS The conductive keratoplasty procedure produced collagen "crumpling and splitting" changes in human corneas, which were observed during the follow-up of 6 months. Areas adjacent to treatment site were minimally damaged.
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Affiliation(s)
- Tatiana L Naoumidi
- University of Crete, School of Medicine, Vardinoyannion Eye Institute of Crete, Voutes PO 1352, 71110 Heraklion, Crete, Greece.
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Hersh PS, Fry KL, Chandrashekhar R, Fikaris DS. Conductive keratoplasty to treat complications of LASIK and photorefractive keratectomy. Ophthalmology 2005; 112:1941-7. [PMID: 16157379 DOI: 10.1016/j.ophtha.2005.05.017] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2004] [Accepted: 05/16/2005] [Indexed: 11/23/2022] Open
Abstract
PURPOSE To assess the outcomes of conductive keratoplasty (CK) for patients with complications related to LASIK or photorefractive keratectomy (PRK). DESIGN Retrospective, noncomparative, interventional case series. PARTICIPANTS Sixteen eyes of 15 patients were treated using CK after complications of initial LASIK or PRK surgeries. Five cases are described in detail. INTERVENTION Rehabilitative CK was performed. MAIN OUTCOME MEASURES Uncorrected visual acuity (UCVA) and best spectacle-corrected visual acuity (BSCVA), refractive error, keratometry, topography analysis, and a subjective assessment of visual quality. RESULTS After CK treatment, there was a mean improvement in UCVA of 2 lines; 1 eye lost >1 line of UCVA. Best-corrected visual acuity improved or remained the same in 12 of 15 eyes; no eyes lost >1 line of BSCVA. There was a mean reduction in astigmatism of 54%. Videokeratography generally demonstrated improved quality of the corneal optical surface, and patients reported a reduction in optical symptoms such as glare and halo. CONCLUSIONS Conductive keratoplasty may give improved corneal optics and vision in patients with complications of LASIK or PRK. This application of CK offers an alternative in cases in which further flap manipulation or laser treatments are contraindicated.
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Affiliation(s)
- Peter S Hersh
- Cornea and Laser Eye Institute-Hersh Vision Group, Teaneck, New Jersey 07666, USA.
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Pallikaris IG, Naoumidi TL, Astyrakakis NI. Long-term results of conductive keratoplasty for low to moderate hyperopia. J Cataract Refract Surg 2005; 31:1520-9. [PMID: 16129286 DOI: 10.1016/j.jcrs.2005.01.032] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 01/12/2005] [Indexed: 11/24/2022]
Abstract
PURPOSE To assess the long-term safety, efficacy, predictability, and stability of conductive keratoplasty (CK) for the treatment of low to moderate hyperopia and to evaluate the impact of the procedure on the quality of vision. SETTING University of Crete, Medical School, Vardinoyannion Eye Institute of Crete, Crete, Greece. METHODS In this prospective nonrandomized noncontrolled single-center study, 38 eyes of 26 patients (13 women and 13 men) were treated for hyperopia with a Refractec ViewPoint CK system and followed for 30 months. Preoperatively, the mean manifest refraction spherical equivalent (MRSE) was +1.89 diopters (D) +/- 0.6 (SD) (range +1.00 to +3.25 D), and the mean follow-up was 30.9 +/- 1.1 months. All eyes were treated with the regular CK nomogram for the treatment of spherical hyperopia. The treatment consisted of 8 to 32 spots applied to the periphery of the cornea. Mean age was 50.3 +/- 8.8 years (range 31 to 71 years). All treated eyes were analyzed for safety, efficacy, predictability, and stability. RESULTS At 12 months, the MRSE was -0.06 +/- 0.8 D and at 30 months was -0.02 +/- 0.7 D. At 30 months, the mean MRSE was within +/-0.50 D in 68%, within +/-1.00 D in 92%, and within +/-2.00 D in all eyes. At 30 months, uncorrected visual acuity was 20/20 or better in 52.5% and 20/40 or better in 89% of eyes. No eye lost 2 or more Snellen lines or had an induced cylinder of 2.00 D or greater. The procedure did not cause statistically significant changes in contrast sensitivity. CONCLUSION Results show that CK for low to moderate hyperopia is a safe, effective, predictable, and stable procedure.
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Affiliation(s)
- Ioannis G Pallikaris
- University of Crete, Medical School, Vardinoyannion Eye Institute of Crete, Heraklion, Greece
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Kymionis GD, Naoumidi TL, Aslanides IM, Kumar V, Astyrakakis NI, Tsilimbaris M, Pallikaris IG. Intraocular Pressure Measurements After Conductive Keratoplasty. J Refract Surg 2005; 21:171-5. [PMID: 15796223 DOI: 10.3928/1081-597x-20050301-13] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
PURPOSE To determine the possible impact of conductive keratoplasty (CK) on intraocular pressure (IOP) measurements. METHODS A prospective, single-center, noncomparative interventional case series was performed. Baseline and postoperative IOPs were measured by Goldmann applanation tonometry in 32 eyes of 18 patients who underwent CK for hyperopia correction. Mean follow-up was 11.9 months (range: 8 to 18 months). RESULTS After CK, a statistically significant decrease in the measured IOP was observed (before CK: 14.22+/-1.64 vs after CK: 12.66+/-2.21, P<.001). The change in IOP readings postoperatively was not correlated with age, sex, keratometric readings, or attempted correction. CONCLUSIONS Despite the limitations due to the small number of patients enrolled in this study, the applanation tonometer appears to underestimate the true IOP after CK.
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Affiliation(s)
- George D Kymionis
- Department of Ophthalmology, and Vardinoyannion Eye Institute of Crete, University of Crete, Greece.
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Haji SA, Ramonas K, Potapova N, Wang G, Asbell PA. Intraoperative Correction of Induced Astigmatism After Spherical Correction of Hyperopia With Conductive Keratoplasty. Eye Contact Lens 2005; 31:76-9. [PMID: 15798478 DOI: 10.1097/01.icl.0000146169.06755.e0] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
PURPOSE To evaluate the treatment of surgically induced astigmatism intraoperatively during conductive keratoplasty (CK) for correcting hyperopia. METHODS Conductive keratoplasty uses radiofrequency energy applied to the peripheral corneal stroma to shrink the collagen and alter the central cornea to correct hyperopia. Nineteen consecutive patients (27 eyes) who underwent CK for hyperopia and were treated intraoperatively for induced astigmatism were examined. By using automated keratometric readings taken during the procedure, additional spots were applied at the minus cylinder or flat axis at the 7-mm zone until the intraoperative astigmatism was 2 diopters (D) or less. RESULTS The intraoperative treatment reduced the astigmatism by an average of 2.30 +/- 1.32 D (P=0.00001). The mean induced astigmatism was 3.33 +/- 0.14 D for eyes that received eight spots, 4.12 +/- 1.13 D for eyes that received 16 spots, 4.43 +/- 0.82 D for eyes that received 24 spots, and 4.60 +/- 1.08 D for eyes that received 32 spots. Additional spots reduced astigmatism in most patients to less than 2 D. CONCLUSIONS Intraoperative treatment of astigmatism through the addition of more spots at the minus cylinder or flat axis reduced the degree of induced astigmatism. Surgically induced astigmatism was observed more frequently in patients who received 32 treatment spots and 6-mm treatment zone application.
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Affiliation(s)
- Shamim A Haji
- Department of Ophthalmology, Mount Sinai School of Medicine, New York, NY 10029, USA
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Berjano EJ, Alió JL, Saiz J. Modeling for radio-frequency conductive keratoplasty: implications for the maximum temperature reached in the cornea. Physiol Meas 2005; 26:157-72. [PMID: 15798292 DOI: 10.1088/0967-3334/26/3/002] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Conductive keratoplasty (CK) is a new surgical technique for steepening the contours of the cornea to reduce hyperopia. It has been emphasized that during CK, tissue resistance to radio-frequency electrical current flow generates a localized heat with temperatures between 65 and 75 degrees C; however, we hypothesize that the maximum temperature reached in the cornea may be higher. For this reason, we developed a finite-element model to estimate the temperature distributions in the cornea during CK. The time evolution of the impedance obtained from computer simulations was compared to that obtained in an experimental study previously published. Our results show that during a typical CK with a 60% setting power (equivalent to 200 V peak-to-peak), the cornea may reach temperatures over 100 degrees C at the electrode tip. On the other hand, the initial impedance of the cornea has a significant influence on the temperature distribution, while the initial temperature of the cornea is not a significant parameter. The results also suggest that low power settings (30-40%) do not produce temperatures over 100 degrees C. Finally, although the actual voltage waveform during CK is exponential and pulsed, our model based on a constant voltage (with a value equal to the root mean square value) provides a better agreement between the theoretical impedance time evolution and that obtained experimentally.
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Affiliation(s)
- Enrique J Berjano
- Center for Research and Innovation on Bioengineering, Valencia Polytechnic University, Camino de Vera s/n, 46022 Valencia, Spain.
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Abstract
PURPOSE To provide 6-month results of a 1-year clinical trial evaluating conductive keratoplasty (CK) for the treatment of presbyopic symptoms in emmetropic and hyperopic eyes. METHODS A total of 143 patients with presbyopic symptoms were enrolled in this 1-year United States FDA clinical trial and treated to improve near vision in 1 eye (unilateral treatment). In addition, 33 fellow eyes were treated to improve distance vision (bilateral treatment). For near vision correction, the target refraction was up to -2.0 D in the nondominant eye, and for distance vision correction, 0.0 D. Enrolled patients had a preoperative spherical equivalent of plano to +2.00 D, no more than 0.75 D of refractive astigmatism, and were 40 years of age or older. No retreatments were performed. RESULTS Of the eyes treated for near, 77% had uncorrected near vision of J3 or better at 6 months postoperatively. A total of 85% of all patients had binocular distance UCVA of 20/25 or better along with J3 or better near, a combination that represents functional acuity for a presbyope. Sixty-six percent of eyes treated for near had a manifest refractive spherical equivalent (MRSE) within +/- 0.50 D of intended at 6 months. In 89% of eyes, the MRSE changed 0.05 D or less between 3 and 6 months postoperatively. After month 1, the incidence of variables associated with safety was 1% or lower. Seventy-six percent were very satisfied or satisfied with their procedure. CONCLUSIONS CK appears to be very safe and effective in producing functional visual acuity in presbyopic eyes up to 6 months following the procedure. Patient satisfaction with the procedure is similar to that of monovision LASIK.
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Pallikaris LG, Naoumidi TL, Panagopoulou SI, Alegakis AK, Astyrakakis NI. Conductive Keratoplasty for Low to Moderate Hyperopia: 1-year Results. J Refract Surg 2003; 19:496-506. [PMID: 14518738 DOI: 10.3928/1081-597x-20030901-04] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
PURPOSE To assess the safety, efficacy, and stability of conductive keratoplasty in the treatment of low to moderate hyperopia and evaluate the impact of the procedure on the quality of vision. METHODS Thirty-six eyes (25 patients; 13 female and 12 male) were treated for hyperopia up to +3.25 D with a Refractec ViewPoint CK system and followed for 1 year. Mean age was 50.2 +/- 8.7 years (range 31 to 71). RESULTS Before surgery, mean spherical equivalent refraction was +1.90 +/- 0.60 D (range +1.00 to +3.25 D), decreasing at 1 year after conductive keratoplasty to -0.06 +/- 0.80 D, and was within +/- 0.50 D of emmetropia in 68% (24 eyes) and within +/- 2.00 D in all eyes. Twelve months after conductive keratoplasty, uncorrected visual acuity was 20/20 or better in 19 eyes (50%) and 20/40 or better in 32 eyes (89%). No eye lost > or = 2 Snellen lines or had induced cylinder > or = 2.00 D. The mean root mean square values for higher order optical aberrations were 0.060 +/- 0.039 before and 0.174 +/- 0.170 at 3 months after surgery. No statistically significant changes in contrast sensitivity were noted. CONCLUSIONS Conductive keratoplasty for low to moderate hyperopia provided safe, effective, and stable results both in refraction and quality of vision.
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Affiliation(s)
- loannis G Pallikaris
- University of Crete, Medical School, Vardinoyannion Eye Institute of Crete, Heraklion, Greece
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