Journal of refractive and corneal surgery最新文献

{"title":"The Hamburger Institute.","authors":"G. Waring","doi":"10.3928/1081-597X-19940901-06","DOIUrl":"https://doi.org/10.3928/1081-597X-19940901-06","url":null,"abstract":"","PeriodicalId":79348,"journal":{"name":"Journal of refractive and corneal surgery","volume":"10 5 1","pages":"495-7"},"PeriodicalIF":0.0,"publicationDate":"1994-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"70145557","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Noncontact laser photothermal keratoplasty. I: Biophysical principles and laser beam delivery system.","authors":"J. Parel, Q. Ren, G. Simón","doi":"10.3928/1081-597X-19940901-08","DOIUrl":"https://doi.org/10.3928/1081-597X-19940901-08","url":null,"abstract":"BACKGROUND\u0000Thermal shrinkage of stromal collagen is known to produce changes in the corneal curvature. We designed a novel, noncontact laser beam delivery system to perform laser photothermal keratoplasty.\u0000\u0000\u0000MATERIALS AND METHODS\u0000The instrument consisted of a pulsed holmium:YAG laser (2.10-micrometer wavelength, 250-microsecond pulse width, 5-hertz repetition rate) coupled via a monofilament fiber to a common slit-lamp microscope equipped with a polyprism, an adjustable mask, and a projection lens. The system projected an 8-spot annular pattern of infrared laser energy on the cornea to achieve a thermal profile within the stroma and to attain controlled, predictable collagen shrinkage. The system produced treatment patterns of 8 to 32 spots of 150 to 600 microns diameter in concentric rings, continuously adjustable between 3 and 7 mm. The versatility of the system in creating different treatment patterns was tested on thermal paper and human cadaver eyes.\u0000\u0000\u0000RESULTS\u0000A uniform beam profile and different treatment patterns for myopia, hyperopia, and astigmatism were obtained. Myopic correction of 6.00 diopters was demonstrated on cadaver eyes. Corneal topography documented corneal flattening (> 6.00 D) with the following treatment parameters: each spot size on the cornea = 300 microns, radiant exposure of each spot = 18.0 J/cm2, number of pulses = 1, diameter of the treatment ring = 3 mm.\u0000\u0000\u0000CONCLUSIONS\u0000Noncontact slit-lamp microscope laser delivery system for laser photothermal keratoplasty provides flexible and precise selection of laser treatment parameters. It may improve the efficacy of the procedure.","PeriodicalId":79348,"journal":{"name":"Journal of refractive and corneal surgery","volume":"10 5 1","pages":"511-8"},"PeriodicalIF":0.0,"publicationDate":"1994-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"70145644","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Astigmatism following photorefractive keratectomy for myopia.","authors":"Michael Goggin, K. Algawi, Michael O'Keefe","doi":"10.3928/1081-597X-19940901-11","DOIUrl":"https://doi.org/10.3928/1081-597X-19940901-11","url":null,"abstract":"BACKGROUND\u0000Astigmatism following photorefractive keratectomy for myopia has been reported as stable as early as 2 to 3 months. The authors report 36 out of 60 consecutive eyes with variations in the cylindrical component of their refraction at 6 months after laser treatment.\u0000\u0000\u0000METHOD\u0000A standard photorefractive keratectomy was carried out on 60 consecutive eyes in 52 patients over a 7-month period. The manifest refraction of these eyes was followed for 6 months.\u0000\u0000\u0000RESULTS\u0000Thirty-six eyes demonstrated a change in the cylindrical element of their refraction manifested as a change in cylinder power or axis, or both. The mean pretreatment cylinder power in the group that underwent a change in the cylindrical element was significantly higher than the mean of the group where this did not take place. The mean cylinder power change was 0.75 diopters (D) and in 9 eyes this change was 1.00 D or more. The corrected and uncorrected postoperative visual acuities were the same in the two groups.\u0000\u0000\u0000CONCLUSIONS\u0000This observation implies meridional variability in the healing process of the anterior cornea following photorefractive keratectomy.","PeriodicalId":79348,"journal":{"name":"Journal of refractive and corneal surgery","volume":"10 5 1","pages":"540-4"},"PeriodicalIF":0.0,"publicationDate":"1994-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"70145707","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Changes in refraction induced by change in intraocular lens position.","authors":"J. Korynta, J. Bok, J. Cendelín","doi":"10.3928/1081-597X-19940901-14","DOIUrl":"https://doi.org/10.3928/1081-597X-19940901-14","url":null,"abstract":"BACKGROUND\u0000Intraocular lens (IOL) decentration and tilt may affect postoperative refractive errors through spherical aberration of the IOL.\u0000\u0000\u0000METHODS\u0000Through a use of a ray-tracing program and by minimizing algorithm, we calculated theoretical refractive errors for various degrees of IOL decentration and tilt. We compared our results with those obtained by paraxial vergence calculations.\u0000\u0000\u0000RESULTS\u0000IOL decentration and/or tilt shifted postoperative refractive errors toward myopia and astigmatism of oblique origin. For example, a 3-millimeter decentration of an IOL resulted in induction of approximately -2.00 diopters (D) sphere and +0.70 D cylinder. IOL tilt affected refractive errors to a lesser degree. The change in refractive error caused by a combination of IOL decentration and tilt depended on the relationship between the geometrical axes of decentration and tilt. In the case of the least favorable combination of 12 degrees of tilt and 3 mm of decentration, it can reach -7.00 D sphere and +4.00 D cylinder.\u0000\u0000\u0000CONCLUSIONS\u0000IOL decentration and/or tilt increase myopia and astigmatism. They are negligible for small decentrations, but could be sources of substantial postoperative refractive errors if the decentration or tile is large.","PeriodicalId":79348,"journal":{"name":"Journal of refractive and corneal surgery","volume":"10 5 1","pages":"556-64"},"PeriodicalIF":0.0,"publicationDate":"1994-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"70145791","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Myopic keratomileusis by excimer laser on a lathe.","authors":"S. Ganem, D. Aron‐Rosa, M. Gross, S. Rosolen","doi":"10.3928/1081-597X-19940901-18","DOIUrl":"https://doi.org/10.3928/1081-597X-19940901-18","url":null,"abstract":"BACKGROUND\u0000We designed an excimer laser keratomileusis delivery system to increase the regularity of the refractive cut surface and allow greater precision in the level and shape of the ablated zone.\u0000\u0000\u0000METHODS\u0000A parallel faced corneal disc was produced by microkeratectomy from six human eyes and surgical keratectomy in 12 beagle corneas. A 193-nanometer excimer laser that was used to project an oval beam onto the corneal disc was rotated on a flat surface to ensure overlapping of the ovally ablated areas between pulses.\u0000\u0000\u0000RESULTS\u0000Electron microscopy of eye bank lenticules demonstrated a circular smooth regularly concave ablation zone. Histological examination of nine clear corneas confirmed thinning of the stroma without fibroblastic reaction and no epithelial hypertrophy. Mean preoperative corneal power of 43.15 +/- 2.18 decreased postoperatively to 33.61 +/- 2.34.\u0000\u0000\u0000CONCLUSIONS\u0000The new technique of excimer laser keratomileusis has the advantage of a cut surface smoother and the clear zone is devoid of the stepwise concavity and irregularity seen in diaphragm based photoablation delivery systems.","PeriodicalId":79348,"journal":{"name":"Journal of refractive and corneal surgery","volume":"10 5 1","pages":"575-81"},"PeriodicalIF":0.0,"publicationDate":"1994-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"70145862","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Suturing a posterior chamber intraocular lens to the iris through limbal incisions: results in 30 eyes.","authors":"E A Navia-Aray","doi":"","DOIUrl":"","url":null,"abstract":"<p><strong>Background: </strong>I have previously reported a new technique of suture fixation of a posterior chamber intraocular lens (IOL) to the iris through a limbal incision in the absence of a posterior lens capsule. This study evaluated the results of that technique as an alternative to anterior chamber lens implantation or suturing of a posterior chamber lens through the ciliary sulcus and sclera.</p><p><strong>Methods: </strong>The clinical records of 30 consecutive eyes that underwent this procedure between September 1987 and February 1991 were studied retrospectively. Four sutures were attached to four holes in the optic of a posterior chamber IOL. Two sutures on straight needles were passed through a superior limbal wound, to the pupil, reaching the inferior iris to be tied onto this iris. The two upper sutures on curved needles were passed through the pupil and going to the superior iris and then tied.</p><p><strong>Results: </strong>An anterior vitrectomy was done in the pupil in 18 (60%) eyes. The mean postoperative follow-up time was 40 months (range, 24 to 66 months). Nineteen eyes (63%) had visual acuities of 20/40 or better; and 10 eyes (33%) had visual acuities between 20/50 and 20/80. The remaining eye had persistent cystoid macular edema, proven by fluorescein angiography, with 20/100 visual acuity. No serious anterior segment complications occurred. There was mild pigment dispersion on the IOL in four eyes. Four eyes needed timolol drops to lower the intraocular pressure.</p><p><strong>Conclusions: </strong>This technique offers a viable alternative to transscleral fixation of a posterior chamber IOL via a limbal approach.</p>","PeriodicalId":79348,"journal":{"name":"Journal of refractive and corneal surgery","volume":"10 5","pages":"565-70"},"PeriodicalIF":0.0,"publicationDate":"1994-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"18538308","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Myopic keratomileusis by excimer laser on a lathe.","authors":"S Ganem,&nbsp;D Aron-Rosa,&nbsp;M Gross,&nbsp;S Rosolen","doi":"","DOIUrl":"","url":null,"abstract":"<p><strong>Background: </strong>We designed an excimer laser keratomileusis delivery system to increase the regularity of the refractive cut surface and allow greater precision in the level and shape of the ablated zone.</p><p><strong>Methods: </strong>A parallel faced corneal disc was produced by microkeratectomy from six human eyes and surgical keratectomy in 12 beagle corneas. A 193-nanometer excimer laser that was used to project an oval beam onto the corneal disc was rotated on a flat surface to ensure overlapping of the ovally ablated areas between pulses.</p><p><strong>Results: </strong>Electron microscopy of eye bank lenticules demonstrated a circular smooth regularly concave ablation zone. Histological examination of nine clear corneas confirmed thinning of the stroma without fibroblastic reaction and no epithelial hypertrophy. Mean preoperative corneal power of 43.15 +/- 2.18 decreased postoperatively to 33.61 +/- 2.34.</p><p><strong>Conclusions: </strong>The new technique of excimer laser keratomileusis has the advantage of a cut surface smoother and the clear zone is devoid of the stepwise concavity and irregularity seen in diaphragm based photoablation delivery systems.</p>","PeriodicalId":79348,"journal":{"name":"Journal of refractive and corneal surgery","volume":"10 5","pages":"575-81"},"PeriodicalIF":0.0,"publicationDate":"1994-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"18538310","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Noncontact laser photothermal keratoplasty. II: Refractive effects and treatment parameters in cadaver eyes.","authors":"G Simon,&nbsp;Q Ren,&nbsp;J M Parel","doi":"","DOIUrl":"","url":null,"abstract":"<p><strong>Background: </strong>Noncontact laser photothermal keratoplasty may provide a new alternative for the treatment of myopia, hyperopia, and astigmatism. The purpose of this article is to study the refractive effect that laser photoablation keratoplasty is capable of producing on a normal human cadaver cornea, including the relationship between the keratometric changes and laser treatment parameters.</p><p><strong>Methods: </strong>The human cadaver eyes were treated with a holmium laser (pulsed Ho:YAG, 2.10 microns, 250 microseconds) coupled to a maskable, polyprismatic delivery system mounted on either an optical bench or a slit-lamp microscope. Using a topographic videokeratography system, we first investigated the refractive effect that noncontact laser photothermal keratoplasty would produce on a normal cadaver cornea. We then studied the keratometric changes produced by different radiant exposure levels at a fixed treatment pattern, as well as by different treatment patterns at a fixed radiant exposure level. Finally, we studied the possible therapeutic application of laser photothermal keratoplasty for correcting high postoperative astigmatism on a cadaver eye model.</p><p><strong>Results: </strong>For the single-pulse 3-millimeter ring of eight-spot treatment, the keratometric power of the cornea initially increased with the radiant exposure and peaked at 26 J/cm2. The refractive effect was increased by projecting an additional set of eight spots equidistant between the first eight spots on the same diameter ring. Eighteen J/cm2 was the minimal radiant exposure required to produce consistent and predictable keratometric changes. The corneas were flattened using treatment patterns smaller than or equal to 3 mm in diameter and steepened using treatment patterns larger than or equal to 5 mm in diameter. A transition zone between 4 and 5 mm was observed in which minimal and unpredictable keratometric changes of the central cornea occurred. The surgically-induced astigmatism (> 10.00 D) was corrected by progressive laser photothermal keratoplasty treatments.</p><p><strong>Conclusions: </strong>Laser photothermal keratoplasty can acutely steepen and flatten the cornea in human cadaver eyes.</p>","PeriodicalId":79348,"journal":{"name":"Journal of refractive and corneal surgery","volume":"10 5","pages":"519-28"},"PeriodicalIF":0.0,"publicationDate":"1994-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"18536153","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Accommodation of an endocapsular silicone lens (Phaco-Ersatz) in the aging rhesus monkey.","authors":"E Haefliger,&nbsp;J M Parel","doi":"","DOIUrl":"","url":null,"abstract":"<p><strong>Background: </strong>After accommodative changes of endocapsular silicone lenses in presenile nonhuman primates had been confirmed by several authors, this pilot study was designed to evaluate the ability of an artificial lens to restore accommodation in the senile eye of a rhesus monkey that had previously lost most of its accommodative capability.</p><p><strong>Methods: </strong>An injectable silicone lens was implanted in one eye of six rhesus monkeys who were older than 17 years. Accommodation was documented as the amount of decrease of anterior chamber depth after pilocarpine stimulation.</p><p><strong>Results: </strong>Four months after surgery, the decrease of anterior chamber depth was higher in the operated eye with the silicone intraocular lens in the two monkeys who had marked presbyopic changes in the natural lens. One monkey was kept for more than 4 years, retaining a decrease of at least 0.5 mm with the silicone lens, whereas the natural lens failed to show any accommodative change.</p><p><strong>Conclusions: </strong>These findings support recent reports that presbyopia is primarily a consequence of lenticular aging rather than ciliary muscle factors. A pliable injected lens may therefore have the potential to restore accommodation in the senile primate eye.</p>","PeriodicalId":79348,"journal":{"name":"Journal of refractive and corneal surgery","volume":"10 5","pages":"550-5"},"PeriodicalIF":0.0,"publicationDate":"1994-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"18536154","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Noncontact laser photothermal keratoplasty. II: Refractive effects and treatment parameters in cadaver eyes.","authors":"G. Simón, Q. Ren, J. Parel","doi":"10.3928/1081-597X-19940901-09","DOIUrl":"https://doi.org/10.3928/1081-597X-19940901-09","url":null,"abstract":"BACKGROUND\u0000Noncontact laser photothermal keratoplasty may provide a new alternative for the treatment of myopia, hyperopia, and astigmatism. The purpose of this article is to study the refractive effect that laser photoablation keratoplasty is capable of producing on a normal human cadaver cornea, including the relationship between the keratometric changes and laser treatment parameters.\u0000\u0000\u0000METHODS\u0000The human cadaver eyes were treated with a holmium laser (pulsed Ho:YAG, 2.10 microns, 250 microseconds) coupled to a maskable, polyprismatic delivery system mounted on either an optical bench or a slit-lamp microscope. Using a topographic videokeratography system, we first investigated the refractive effect that noncontact laser photothermal keratoplasty would produce on a normal cadaver cornea. We then studied the keratometric changes produced by different radiant exposure levels at a fixed treatment pattern, as well as by different treatment patterns at a fixed radiant exposure level. Finally, we studied the possible therapeutic application of laser photothermal keratoplasty for correcting high postoperative astigmatism on a cadaver eye model.\u0000\u0000\u0000RESULTS\u0000For the single-pulse 3-millimeter ring of eight-spot treatment, the keratometric power of the cornea initially increased with the radiant exposure and peaked at 26 J/cm2. The refractive effect was increased by projecting an additional set of eight spots equidistant between the first eight spots on the same diameter ring. Eighteen J/cm2 was the minimal radiant exposure required to produce consistent and predictable keratometric changes. The corneas were flattened using treatment patterns smaller than or equal to 3 mm in diameter and steepened using treatment patterns larger than or equal to 5 mm in diameter. A transition zone between 4 and 5 mm was observed in which minimal and unpredictable keratometric changes of the central cornea occurred. The surgically-induced astigmatism (> 10.00 D) was corrected by progressive laser photothermal keratoplasty treatments.\u0000\u0000\u0000CONCLUSIONS\u0000Laser photothermal keratoplasty can acutely steepen and flatten the cornea in human cadaver eyes.","PeriodicalId":79348,"journal":{"name":"Journal of refractive and corneal surgery","volume":"10 5 1","pages":"519-28"},"PeriodicalIF":0.0,"publicationDate":"1994-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"70145654","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}