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Abstract
Various materials have been placed in the corneal stroma to modify a spherical refractive error (usually hyperopic). As the surgical procedures evolved to simplify the insertion process so has the quality and biocompatibility of the implanted materials. Failures have been due to excessive inlay dimensions, bioincompatibility of the materials used, poor choice of test model, or combinations of the above. We present a thorough analysis of the history of the intracorneal inlay and the materials and techniques used up to and including the current materials and techniques available for the correction of spherical refractive errors.
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Huseynova T, Kanamori T, Waring GO, Tomita M. Outcomes of small aperture corneal inlay implantation in patients with pseudophakia. J Refract Surg 2014; 30:110-6. [PMID: 24763476 DOI: 10.3928/1081597x-20140120-06] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2013] [Accepted: 11/11/2013] [Indexed: 11/20/2022]
Abstract
PURPOSE To evaluate the improvement in near visual acuity after KAMRA corneal inlay (AcuFocus, Inc., Irvine, CA) implantation in patients with pseudophakia. METHODS A retrospective study analysis of patients with pseudophakia undergoing monocular corneal inlay implantation in the non-dominant eye was performed. The inlay was implanted monocularly in the non-dominant eye of patients. Manifest refractive spherical equivalent, uncorrected distance visual acuity, corrected distance visual acuity, uncorrected near visual acuity, and corrected near visual acuity were evaluated. The follow-up period was 3 months. RESULTS Thirteen eyes from 13 patients were evaluated. Four patients underwent LASIK for improved distance acuity at the time of inlay implantation. Mean uncorrected near visual acuity improved five lines (from J10 to J4) postoperatively. Mean uncorrected distance visual acuity, corrected distance visual acuity, and corrected near visual acuity remained stable and were 20/20, 20/16, and J1, respectively, before and after KAMRA implantation. Three eyes lost two lines and 1 eye lost one line of uncorrected distance visual acuity. Two eyes lost two lines and 1 eye lost 1 line of corrected distance visual acuity. Mean manifest refractive spherical equivalent changed before and after KAMRA implantation from -0.01 ± 1.07 diopters (D) (range: 2.25 to -1.88 D) to -1.12 ± 0.87 D (range: 0.25 to -2.75 D), respectively. CONCLUSIONS Implantation of a small aperture corneal inlay improved uncorrected near visual acuity while maintaining uncorrected and corrected distance visual acuity in monofocal patients with pseudophakia.
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Biomaterials for refractive correction: corneal onlays and inlays. Sci China Chem 2014. [DOI: 10.1007/s11426-014-5083-1] [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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Ozulken K, Cabot F, Yoo SH. Applications of femtosecond lasers in ophthalmic surgery. Expert Rev Med Devices 2014; 10:115-24. [DOI: 10.1586/erd.12.59] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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Abstract
PURPOSE To assess the efficacy of a small aperture corneal inlay (KAMRA, AcuFocus Inc) to improve near vision in emmetropic presbyopes. METHODS Prospective, nonrandomized, multicenter clinical trial in presbyopic emmetropes aged 45 to 60 years. A small corneal pocket or flap was created in the nondominant eye by femtosecond laser or mechanical microkeratome, and the inlay (N=507) placed on the stromal bed. Uncorrected visual acuity was measured for the implanted eye at near (40 cm), intermediate (80 cm), and distance (20 ft) using ETDRS charts with the Optec 6500 Vision Tester (Stereo Optical Inc) at the preoperative, and 1-, 3-, 6-, 9-, 12-, and 18-month postoperative examinations. Contrast sensitivity (CS) was measured with best distance correction in the implanted eye using the Optec system and FACT chart under photopic (85 cd/m(2)) and mesopic (3 cd/m(2)) conditions preoperatively and at 1-year follow-up. RESULTS Mean patient age was 52.87±3.64 years. Monocular mean uncorrected near visual acuity was J8 (0.482±0.925 logMAR) preoperatively, J3 (0.185±0.848 logMAR) at 1 month (n=506, P<.0001), and J2 (0.139±0.851 logMAR) at 18 months (n=99, P<.0001). Mean uncorrected intermediate visual acuity was 20/35 (0.239±0.837 logMAR) preoperatively and 20/26 (0.139±0853 logMAR) at 18 months (P<.0001). Mean uncorrected distance visual acuity (UDVA) was 20/20 (0.011±0.890 logMAR) at 18 months. Photopic (P<.001) and mesopic (P<.0001) monocular contrast sensitivities were within the range of the normal population at 1 year. CONCLUSIONS The KAMRA corneal inlay improved near visual acuity with minimal impact on UDVA or mesopic contrast sensitivity in the implanted eye.
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Affiliation(s)
- George O Waring
- ReVision Advanced Laser Eye Center, Columbus, Ohio 43240, USA.
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McAlinden C. Corneal refractive surgery: past to present. Clin Exp Optom 2012; 95:386-98. [PMID: 22672114 DOI: 10.1111/j.1444-0938.2012.00761.x] [Citation(s) in RCA: 51] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/27/2011] [Revised: 04/07/2012] [Accepted: 04/17/2012] [Indexed: 12/20/2022] Open
Abstract
There have been many historical corneal refractive techniques and procedures developed over the years. From early techniques of radial keratotomy to modern excimer laser techniques, the field of refractive surgery is one of the most rapidly developing in ophthalmology. This review details the historical aspects of the many early techniques up to current techniques used on millions of eyes around the world.
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Affiliation(s)
- Colm McAlinden
- University of Ulster, United Kingdom and Flinders Medical Centre and Flinders University, Adelaide, South Australia, Australia.
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Tomita M, Kanamori T, Waring GO, Yukawa S, Yamamoto T, Sekiya K, Tsuru T. Simultaneous corneal inlay implantation and laser in situ keratomileusis for presbyopia in patients with hyperopia, myopia, or emmetropia: six-month results. J Cataract Refract Surg 2012; 38:495-506. [PMID: 22340607 DOI: 10.1016/j.jcrs.2011.10.033] [Citation(s) in RCA: 73] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2010] [Revised: 10/11/2011] [Accepted: 10/14/2011] [Indexed: 11/17/2022]
Abstract
PURPOSE To evaluate the safety and efficacy of simultaneous Kamra corneal inlay implantation and laser in situ keratomileusis (LASIK) for the treatment of presbyopia in emmetropic, hyperopic, or myopic patients. SETTING Private center, Tokyo, Japan. DESIGN Cohort study. METHODS Patients had bilateral LASIK with simultaneous implantation of a corneal inlay in the nondominant eye to treat presbyopia and ametropia between September 2009 and April 2010. The efficacy and safety were determined by the spherical equivalent (SE) in the eye with the inlay. RESULTS The study enrolled 360 eyes of 180 patients with a mean age of 52.4 years ± 5.1 (SD) (range 41 to 65 years). Sixty-four patients were available for the 6-month postoperative examination. The mean logMAR uncorrected near visual acuity in the eye with the inlay improved 7 lines in hyperopic eyes, 6 lines in emmetropic eyes, and 2 lines in myopic eyes. The mean logMAR uncorrected distance visual acuity improved by 3 lines, 1 line, and 10 lines, respectively. CONCLUSIONS Simultaneous intracorneal inlay implantation and LASIK to treat presbyopia with emmetropia, hyperopia, or myopia was clinically safe and effective, yielding improvement in distance and near visual acuity. Patients were satisfied with decreased dependence on reading glasses regardless of the preoperative SE range. However, postoperative symptoms, such as dry eyes, halo, glare, or night-vision disturbances, occurred occasionally. FINANCIAL DISCLOSURE Dr. Waring has a financial interest in and is world surgical monitor for Acufocus. No other author has a financial or proprietary interest in any material or method mentioned.
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Hydrogel intracorneal inlays for the correction of hyperopia: outcomes and complications after 5 years of follow-up. Ophthalmology 2009; 116:1455-60, 1460.e1. [PMID: 19651310 DOI: 10.1016/j.ophtha.2009.05.019] [Citation(s) in RCA: 69] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2008] [Revised: 05/05/2009] [Accepted: 05/12/2009] [Indexed: 11/24/2022] Open
Abstract
PURPOSE To evaluate safety and efficacy of an intracorneal inlay for the correction of hyperopia. DESIGN A prospective, nonrandomized, noncomparative, 2-center study. PARTICIPANTS Thirty-four hyperopic eyes were implanted with a hydrogel intracorneal inlay (Permavision, Anamed, Lake Forest, CA). Preoperative hyperopia was +3.9 diopter (D; range, +2 to +7). Uncorrected visual acuity (UCVA) was the logarithm of the minimum angle of resolution (logMAR; the decimal logarithm of decimal visual acuity with a minus sign) 0.6 +/- logMAR 1, and best-corrected visual acuity (BCVA) was logMAR 0.1 +/- 0.7. METHODS Corneal flaps were created with a mechanical microkeratome (M2 [Moria, Anthony, France] or Amadeus [Advanced Medical Optics Inc, Santa Ana, CA]; 180 microm), followed by inlay implantation onto the stromal bed over the pupillary center and covered by the corneal flap. Follow-up was 5 years. MAIN OUTCOME MEASURES We measured UCVA and BCVA; patients underwent, slit-lamp examination, pachymetry, and confocal microscopy. The follow-up was up to 6 years. RESULTS The UCVA improved during 3 months and was stable for up to 2 years. There was a loss of > or =2 lines of spectacle-corrected visual acuity in 35% of eyes at 2 years, and a loss of > or =2 lines in 55.5% of the eyes at 5 years. Refractive predictability was poor, with 60% of the eyes having +/-3.00 D of emmetropia. A decentration of the inlay occurred in 29.4%, progressive perilenticular deposits were observed in 88.2%, haze was seen in 73.5%, and the inlay was explanted in 58.8%, with a cumulative survival rate of 58.4%. CONCLUSIONS An intracorneal inlay may be an option to treat hyperopia, but the tested inlay caused significant visual loss and scarring and had to be explanted in the majority of cases.
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Gimbel HV, Kaye GB, Ferensowicz M. Results of Photorefractive Keratectomy in High Myopia and Hyperopia. Semin Ophthalmol 2009. [DOI: 10.3109/08820539609063817] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
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Sweeney DF, Vannas A, Hughes TC, Evans MD, McLean KM, Xie RZ, Pravin VK, Prakasam RK. Synthetic corneal inlays. Clin Exp Optom 2008; 91:56-66. [PMID: 18045251 DOI: 10.1111/j.1444-0938.2007.00198.x] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022] Open
Abstract
This review is based on the activities of the Vision Cooperative Research Centre (previously Cooperative Research Centre for Eye Research and Technology) Corneal Implant team from 1991 to 2007. The development of a synthetic polymer of perfluoropolyether (PFPE), meeting essential physical and biological requirements, for use as a corneal inlay is presented. Each inlay was placed in a corneal flap created with a microkeratome and monitored over a two-year period in a rabbit model. The results indicate that the PFPE implant shows excellent biocompatibility and biostability. As a result, a Phase 1 clinical trial is being conducted. Three years post-implantation, the PFPE inlays are exhibiting continued excellent biocompatibility. Corneal inlays made from PFPE are biocompatible with corneal tissue in the long term and offer a safe and biologically-acceptable alternative to other forms of refractive surgery.
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Sweeney DF. The Max Schapero Memorial Award Lecture 2004: Contact Lenses on and in the Cornea, What the Eye Needs. Optom Vis Sci 2006; 83:133-42. [PMID: 16534455 DOI: 10.1097/01.opx.0000204517.71174.e5] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022] Open
Abstract
PURPOSE The aim of this study is to review the advances made in understanding the needs of the cornea and the way in which it responds to contact lens wear and corneal implants. METHODS The review is based on personal knowledge and involvement of the author and colleagues from the 1970s to 2005. RESULTS Development of silicone hydrogel contact lenses is presented as well as development of synthetic materials for implantation on the corneal surface (corneal onlay). CONCLUSIONS The future of vision correction involves developing highly porous and biocompatible lens materials. For contact lenses, a better understanding of the effects of contact lens wear on the ocular surfaces, including the tear film, and development of lens materials with greater bacterial resistance are required. For those who require new solutions to permanent vision correction, corneal onlays (implantable contact lenses) are a minimally invasive and totally reversible procedure that can be removed or replaced as visual needs change over time.
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Alió JL, Shabayek MH, Montes-Mico R, Múlet ME, Ahmed AG, Merayo J. Intracorneal Hydrogel Lenses and Corneal Aberrations. J Refract Surg 2005; 21:247-52. [PMID: 15977881 DOI: 10.3928/1081-597x-20050501-07] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
PURPOSE To investigate the optical performance of the cornea based on corneal aberrometry following intracorneal hydrogel lens implantation. METHODS A retrospective, nonconsecutive, observational study of the anterior corneal surface aberration profile of four hyperopic eyes previously implanted with an intracorneal hydrogel lens were studied by videokeratographic elevation maps before and 6 months after surgery. RESULTS Intracorneal hydrogel lenses reduced the optical performance in all four eyes by increasing the spherical aberrations by a mean factor of 1.87 and 1.95, coma aberrations by a mean factor of 2.98 and 3.01, and total higher order aberrations by a mean factor of 2.6 and 2.17 at 3.0-mm and 6.5-mm pupils, respectively (P<.005). CONCLUSIONS Intracorneal hydrogel lenses decreased the optical performance of the cornea by significantly increasing spherical, coma, and total higher order aberrations.
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Affiliation(s)
- Jorge L Alió
- Department of Refractive Surgery, Vissum Instituto Oftalmológico de Alicante and Division of Ophthalmology, Miguel Hernández University, Medical School, Alicante, Spain.
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Peyman GA, Beyer CF, Bezerra Y, Vincent JM, Arosemena A, Friedlander MH, Hoffmann L, Kangeler J, Roussau D. Photoablative inlay laser in situ keratomileusis (PAI-LASIK) in the rabbit model. J Cataract Refract Surg 2005; 31:389-97. [PMID: 15767164 DOI: 10.1016/j.jcrs.2004.06.028] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 04/14/2004] [Indexed: 11/19/2022]
Abstract
PURPOSE To evaluate the suitability, biocompatibility, and efficacy of a proprietary hydrogel photoablative inlay (PAI) for use during laser in situ keratomileusis (LASIK). SETTING Laboratory study, Tulane University Health Sciences Center, New Orleans, Louisiana, USA. METHODS Eight rabbits (1 eye each) underwent the PAI-LASIK procedure; 4 eyes had a disk-shaped inlay and 4, a donut-shaped inlay. Preoperatively, the hydrogel material was ablated with a programmed correction of 5.0 diopters of hyperopia or myopia. RESULTS The eyes were followed for 1 to 16 months. No eye showed signs of rejection or extrusion of the PAI. There was no significant difference in corneal clarity or the healing rate between eyes with donut-shaped PAIs and those with disk-shaped PAIs. One eye with a donut-shaped PAI had minimal corneal haze. The remaining inlays did not opacify or fracture during ablation. CONCLUSION The hydrogel material can be used for the proposed PAI-LASIK procedure.
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Affiliation(s)
- Gholam A Peyman
- Department of Ophthalmology, Tulane University Health Sciences Center, New Orleans, Louisiana 70112-2699, USA
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Thompson RW, Choi DM, Price FW. Clear lens replacement surgery. Int Ophthalmol Clin 2002; 42:131-52. [PMID: 12409928 DOI: 10.1097/00004397-200210000-00013] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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Abstract
PURPOSE To review the major advances in the field of refractive surgery occurring over the past 25 years. METHODS Literature review. RESULTS The major developments in refractive surgery over the past 25 years are reviewed. CONCLUSIONS The past 25 years have witnessed great changes in refractive surgery. As a result of advancements in technology, instrumentation, and technique, we have seen improvements in the treatment of all types of ametropias. In this article, we review some of the successes and failures of the past quarter-century.
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Affiliation(s)
- R D Stulting
- Cornea Service, Emory University School of Medicine, Department of Ophthalmology, Atlanta, Georgia, USA
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Pérez-Santonja JJ, Ayala MJ, Sakla HF, Ruíz-Moreno JM, Alió JL. Retreatment after laser in situ keratomileusis. Ophthalmology 1999; 106:21-8. [PMID: 9917776 DOI: 10.1016/s0161-6420(99)90001-5] [Citation(s) in RCA: 52] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022] Open
Abstract
OBJECTIVE To evaluate the effectiveness, predictability, and safety of laser in situ keratomileusis (LASIK) retreatment for correcting residual myopia. DESIGN Retrospective noncomparative case series. PARTICIPANTS AND INTERVENTION Fifty-nine consecutive eyes (43 patients) underwent LASIK retreatment at 3 or 6 months after the primary LASIK procedure. Lifting the corneal flap and reablating the stromal bed with a VISX 20/20 excimer laser was the procedure used for LASIK enhancement. MAIN OUTCOME MEASURES The following parameters were studied before and after retreatment: visual acuity, refraction, videokeratography, applanation tonometry, and corneal thickness. Complications after LASIK enhancement also were evaluated. Follow-up was 12 months. RESULTS Before retreatment, only 3.38% of eyes (2 of 59) had an uncorrected visual acuity of 0.5 (20/40) or better, and after retreatment, this percentage increased to 60% (30 of 50) at 6 months and 61.8% (34 of 55) at 12 months. After reoperation, mean best-corrected visual acuity improved by half a line over the values before retreatment. The preretreatment refraction of -2.92 +/- 1.22 diopters (D) (mean +/- standard deviation) decreased significantly to -0.44 +/- 0.80 D at 6 months and to -0.61 +/- 0.82 D at 12 months (P < 0.001). In 82% of eyes (41 of 50) at 6 months and 81.8% (45 of 55) at 12 months, the spherical equivalent was within 1.00 D of emmetropia. There was a significant regression of effect (0.38 D) between 3 and 12 months (P < 0.01). Postretreatment refraction was related to the original refraction before the primary LASIK, the preretreatment refraction, and the ablation diameter used. Although no vision-threatening complications were found, epithelial ingrowth and flap melting were more common after than before LASIK retreatment, with 31% of eyes at 12 months with epithelial ingrowth and 10.9% with flap melting. However, LASIK enhancement improved decentration and night-vision problems. CONCLUSIONS LASIK retreatment was an effective and predictable procedure for correcting residual myopia. Epithelial ingrowth and flap melting were more frequent after than before LASIK retreatment, whereas decentration and night-vision symptoms improved.
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Affiliation(s)
- J J Pérez-Santonja
- Refractive Surgery and Cornea Unit, Alicante Institute of Ophthalmology, University of Alicante School of Medicine, Spain
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Menezo JL, Cisneros AL, Rodriguez-Salvador V. Endothelial study of iris-claw phakic lens: four year follow-up. J Cataract Refract Surg 1998; 24:1039-49. [PMID: 9719962 DOI: 10.1016/s0886-3350(98)80096-5] [Citation(s) in RCA: 142] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
PURPOSE To study quantitative and morphometric endothelial changes in phakic eyes implanted with the Worst iris-claw lens to correct high myopia. SETTING Department of Ophthalmology, University Hospital "La Fe", Valencia, Spain. MATERIAL AND METHODS This retrospective study involved 111 phakic eyes (73 patients) implanted with the Worst iris-claw lens. Noncontact specular microscopy and computer-assisted analysis was performed preoperatively and 6 months and 1, 2, 3, and 4 years postoperatively. RESULTS The mean cell loss was 3.85% at 6 months, 6.59% at 1 year, 9.22% at 2 years, 11.68% at 3 years, and 13.42% at 4 years. At 2 years, the hexagonality and coefficient variation in cell size were close to the preoperative levels. No major complications were seen; early postoperative corneal touch required intraocular lens (IOL) removal in 1 case (0.9%). Four eyes (3.6%) needed a reoperation because of poor IOL fixation (2 eyes), traumatic subluxation of the IOL (1 eye), and miscalculation of the IOL power (1 eye). CONCLUSIONS Although there was a slight progressive cell loss after IOL implantation, the morphometric changes recovered and were close to the preoperative levels. This suggests that endothelial damage occurred primarily during the surgical procedure.
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Affiliation(s)
- J L Menezo
- Department of Ophthalmology, University Hospital La Fe, University of Valencia, Spain
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Chirila TV, Hicks CR, Dalton PD, Vijayasekaran S, Lou X, Hong Y, Clayton AB, Ziegelaar BW, Fitton J, Platten S, Crawford GJ, Constable IJ. Artificial cornea. Prog Polym Sci 1998. [DOI: 10.1016/s0079-6700(97)00036-1] [Citation(s) in RCA: 96] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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Menezo JL, Aviño JA, Cisneros A, Rodriguez-Salvador V, Martinez-Costa R. Iris Claw Phakic Intraocular Lens for High Myopia. J Refract Surg 1997; 13:545-55. [PMID: 9352483 DOI: 10.3928/1081-597x-19970901-11] [Citation(s) in RCA: 83] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
BACKGROUND The implantation of a Worst-Fechner iris claw intraocular lens (IOL) is one of the surgical procedures used for the correction of high myopia. This technique reduces myopia with stable refractive results; however, its potential long-term risks have not been evaluated. We report results in 94 eyes with a minimum follow-up of 3 years. METHODS We studied 94 eyes of 62 patients with myopia > or = -7.00 diopters (D) who underwent Worst-Fechner IOL implantation. Lens decentration, permeability of the blood-aqueous barrier by iris angiography, and changes in corneal endothelial density were analyzed. RESULTS Mean follow-up time was 48.9 months (range 36 to 72 mo). Three years after surgery, 58 eyes (61%) had an uncorrected visual acuity > or = 20/40, and 77 eyes (82%) gained two or more lines of spectacle-corrected visual acuity with respect to the preoperative value; 75 eyes (79%) were within +/- 1.00 D of emmetropia and 46 eyes (48%) were within +/- 0.50 D of emmetropia. The mean endothelial cell loss was 17.9% at 5 years after surgery, while the percentage of hexagonality and the coefficient of cell variation tended toward preoperative levels. No vision threatening complications were seen. CONCLUSIONS The implantation of a Worst-Fechner iris claw phakic IOL reduced high myopia with a stable refractive outcome. Endothelial cell damage was within acceptable limits. The absence of major complications makes this procedure an acceptable method for correcting high myopia.
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Affiliation(s)
- J L Menezo
- La Fe University Hospital, University of Valencia School of Medicine, Department of Ophthalmology, Spain
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Abstract
PURPOSE To assess the efficacy, stability, and safety of Permalens hydrogel intracorneal lenses for the correction of spherical ametropia 6 years after implantation. METHODS Implantation of intracorneal hydrogel lenses was performed by the same surgeon (JIBM) in five aphakic and five high myopic eyes. The lens closet to corneal vertex refraction was used. Refractive outcomes, keratometry, keratography, endothelial cell count, and corneal topography were studied. RESULTS Corneal tolerance to the hydrogel implants was maintained throughout for 6 years with no alteration in endothelial cell count. All myopic eyes showed regression of achieved correction. The aphakic eyes showed no statistically significant difference between the results at 1 month and those obtained at 1 and 6 years. CONCLUSIONS Hyrdogel intracorneal lenses are well tolerated and the refractive results are stable in aphakic patients. They may be considered when intraocular lenses cannot be placed in aphakic patients, but are not now in clinical use.
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Affiliation(s)
- J I Barraquer
- Barraquer Institute of America, Santa fe de Bogota, Colombia
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Pérez-Santonja JJ, Bellot J, Claramonte P, Ismail MM, Alió JL. Laser in situ keratomileusis to correct high myopia. J Cataract Refract Surg 1997; 23:372-85. [PMID: 9159682 DOI: 10.1016/s0886-3350(97)80182-4] [Citation(s) in RCA: 256] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
PURPOSE To evaluate the effectiveness, predictability, and safety of laser in situ keratomileusis (LASIK) in 143 eyes with myopia from 8.00 to 20.00 diopters (D). SETTING Alicante Institute of Ophthalmology, University of Alicante School of Medicine, Alicante, Spain. METHODS This prospective study comprised 143 eyes (94 patients) that had LASIK with the Chiron Automated Corneal Shaper and the VISX 20/20 excimer laser using a multizone profile and a sutureless hinged corneal flap technique. RESULTS Uncorrected visual acuity of 20/40 or better in 45.0% of eyes 3 months postoperatively and in 46.4% at 6 months. Best corrected visual acuity (BCVA) improved by 0.07 at 3 and 6 months and was stable after 3 months. Mean spherical equivalent was -13.19 diopters (D) +/- 2.89 (SD) preoperatively and +0.51 +/- 1.63 D at 3 months and +0.18 +/- 1.66 D at 6 months postoperatively. At 3 months, spherical equivalent was within 1.00 D of emmetropia in 57.5% of all eyes, 71.0% of eyes with a baseline refraction from -8.00 to -11.99 D (n = 59), 44.4% with a baseline refraction from -12.00 to -15.99 D (n = 54), and 53.0% of eyes with a baseline refraction from -16.00 to -20.00 D (n = 30). The respective 6 month percentages were 60.0, 72.4, 46.0, and 50.0%. The regression of effect was similar in all groups (approximately 0.50 D) between 1 and 3 months, although the high myopia group had further regression. Significant corneal steepening and an increase in corneal thickness occurred between 1 and 3 months. Flap thickness was always less than predicted with both the 130 microns plates, and achieved laser ablation was deeper than programmed. The relationships between postoperative refraction and preoperative keratometry and postoperative refraction and the difference in achieved versus programmed ablation were significant. Complications at 6 months included epithelial ingrowth, corneal flap melting, decentered ablation, and irregular astigmatism with loss of BCVA, although none was vision threatening. CONCLUSION In this study, LASIK was effective and predictable in the correction of high myopia but was more accurate for myopia up to 12.00 D. Current surgical algorithms must be modified to improve predictability in higher corrections. Longer follow-up is necessary to evaluate long-term incidence of vision-threatening complications.
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Affiliation(s)
- J J Pérez-Santonja
- Refractive Surgery Section, Alicante Institute of Ophthalmology, University of Alicante, School of Medicine, Spain
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Parks RA, Assil KK, Schanzlin DJ. Intracorneal implants. Semin Ophthalmol 1994; 9:125-9. [PMID: 10172081 DOI: 10.3109/08820539409060006] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Affiliation(s)
- R A Parks
- Department of Ophthalmology, Anheuser-Busch Eye Institute, Saint Louis University, MO 63104
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Chirila TV, Vijayasekaran S, Horne R, Chen YC, Dalton PD, Constable IJ, Crawford GJ. Interpenetrating polymer network (IPN) as a permanent joint between the elements of a new type of artificial cornea. JOURNAL OF BIOMEDICAL MATERIALS RESEARCH 1994; 28:745-53. [PMID: 8071386 DOI: 10.1002/jbm.820280612] [Citation(s) in RCA: 83] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
The combination at the interface between two chemically identical polymers was investigated by light and electron (scanning, transmission) microscopy. The polymers constitute elements of a new type of artificial cornea in which the peripheral skirt is made from spongy poly(2-hydroxyethyl methacrylate) (PHEMA) and the central optical zone from homogeneous, transparent PHEMA. Their two-phase combination along the boundary fulfill formally the requirements for an interpenetrating polymer network (IPN). The procedure for the manufacture of prosthesis was described in detail. Thin and ultrathin sections excised from the interface region were investigated using microscopic techniques. Light microscopy allowed the measurement of the diffusion path length of transparent PHEMA into sponge, which was approximately 0.5 mm. Transmission electron microscopy revealed a cellular-like morphology as well as larger segregated zones, which indicated network interpenetration on a molecular level and also a relatively poor miscibility of the two polymers despite their identical chemical structure. The latter was interpreted as a result of the submicroscopic restraints imposed by polymer I (sponge) upon polymer II. This study provides evidence that the interface combination of the prosthetic elements should be regarded as a gradient homo-IPN. This system offers a union between elements much stronger than those previously reported in artificial corneas.
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Affiliation(s)
- T V Chirila
- Lions Eye Institute, Nedlands, Western Australia
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25
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Nosé W, Neves RA, Schanzlin DJ, Belfort R. Intrastromal Corneal Ring-One-Year Results of First Implants in Humans: A Preliminary Nonfunctional Eye Study. J Refract Surg 1993. [DOI: 10.3928/1081-597x-19931101-09] [Citation(s) in RCA: 58] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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