Journal Of Refractive And Corneal Surgery[JOURNAL]
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105 papers
Endothelial change after excimer laser photorefractive keratectomy.
Toda I, Tsubota K, Itoh S
J Refract Corneal Surg · 1994 · PMID 7522098
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Refractive surgery goes mainstream: establishing radial keratotomy services at a suburban community hospital.
Epstein RJ
J Refract Corneal Surg · 1994 · PMID 7522097
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Excimer laser photorefractive keratectomy for treatment of keratoconus.
Mortensen J, Ohrström A
J Refract Corneal Surg · 1994 · PMID 7522096
BACKGROUND: Five eyes with keratoconus that were scheduled for penetrating keratoplasty were treated instead with excimer laser photorefractive keratectomy to reduce the steepness of the cone. The follow up after 6 to 12...
BACKGROUND: Five eyes with keratoconus that were scheduled for penetrating keratoplasty were treated instead with excimer laser photorefractive keratectomy to reduce the steepness of the cone. The follow up after 6 to 12 months is reported here. METHODS: A 193-nanometer excimer laser system VISX 20/20 was used for correction of myopia or astigmatism. The patients had a complete ophthalmological examination including slit-lamp microscopy and videokeratography. The patients were followed with six examinations during a period of at least 6 months. RESULTS: In four eyes, a reduction of the astigmatism was achieved with an increase of visual acuity. There were no problems with wound healing or any signs that the excimer adversely affected the cornea or activated the keratoconus disease process. CONCLUSION: The treatment of keratoconus with excimer laser has been regarded as seriously contraindicated on a speculative basis. This risk seems to be exaggerated.
A surgical technique for the treatment of central corneal perforations.
Vrabec MP, Jordan JJ
J Refract Corneal Surg · 1994 · PMID 7522095
BACKGROUND: Generally, corneal perforations of 2 mm in diameter or greater are treated using graft material for tectonic support. A surgical technique for the primary repair of such perforations without the use of any ad...
BACKGROUND: Generally, corneal perforations of 2 mm in diameter or greater are treated using graft material for tectonic support. A surgical technique for the primary repair of such perforations without the use of any additional tissue is presented. METHODS: This procedure is demonstrated by a case report. The technique involves creation of an elliptical defect out of a circular one, thus allowing for primary closure, with the addition of glue. A definitive penetrating keratoplasty was subsequently performed with several important modifications described herein. RESULTS: A water-tight closure was obtained with this technique for 1 month while the inflammation subsided. Preoperative visual acuity was light perception. One year postoperatively, it was count fingers at 8 feet with mild irregular astigmatism. CONCLUSION: This technique is useful for perforations which are central, larger than 2 mm in diameter, and when corneal or scleral material is not readily available for patch grafting.
Corneal ectasia as a complication of repeated keratotomy surgery.
Wellish KL, Glasgow BJ, Beltran F … +1 more , Maloney RK
J Refract Corneal Surg · 1994 · PMID 7522094
BACKGROUND: Staged keratotomy surgery, or "enhancement surgery," may allow a more predictable outcome, but also subjects the patient to additional surgical risks. METHODS: A 39-year-old man underwent astigmatic keratotom...
BACKGROUND: Staged keratotomy surgery, or "enhancement surgery," may allow a more predictable outcome, but also subjects the patient to additional surgical risks. METHODS: A 39-year-old man underwent astigmatic keratotomy for myopic astigmatism, followed by 12 enhancement procedures for residual astigmatism. RESULTS: These procedures effectively resulted in a double hexagonal keratotomy. The patient's best spectacle-corrected acuity deteriorated to counting fingers. Clinically, a conically-shaped protrusion of the central cornea, Munson's sign, diffuse subepithelial scarring, and central corneal thinning were noted. Penetrating keratoplasty was performed. Histopathologic examination showed central thinning, epithelial edema, disruption of Bowman's layer, marked stromal scarring, and focal areas of endothelial attenuation--findings consistent with keratoconus. CONCLUSION: This case illustrates that multiple keratotomy procedures may result in corneal ectasia in apparently normal eyes and suggests that hexagonal keratotomy may be more likely to cause iatrogenic keratoconus.
Corneal epithelial dots following excimer laser photorefractive keratectomy.
Busin M, Meller D
J Refract Corneal Surg · 1994 · PMID 7522093
BACKGROUND: Map-dot-fingerprint epithelial changes of the cornea have been reported to occur as a consequence of trauma or surgical procedures, such as radial keratotomy. METHODS: We describe a case of dot-like changes i...
BACKGROUND: Map-dot-fingerprint epithelial changes of the cornea have been reported to occur as a consequence of trauma or surgical procedures, such as radial keratotomy. METHODS: We describe a case of dot-like changes in the corneal epithelium following excimer laser photorefractive keratectomy for the correction of myopia. Because the lesions were located centrally, possibly reducing visual acuity, the epithelium was removed mechanically. RESULTS: Dot-like changes recurred in the same areas 4 weeks after epithelial debridement. Best spectacle-corrected visual acuity improved from 20/200 to 20/100 and remained stable thereafter. CONCLUSIONS: Photorefractive keratectomy can lead to abnormal regeneration of epithelium basement membrane, possibly resulting in dot-like changes of corneal epithelium.
Biomechanical behavior of the cornea and its response to radial keratotomy.
Simon G, Ren Q
J Refract Corneal Surg · 1994 · PMID 7522092
BACKGROUND: Radial keratotomy reduces myopia by flattening the central cornea, but the mechanism remains a matter of controversy. In this article, we studied the biomechanical behavior of the cornea and its response to r...
BACKGROUND: Radial keratotomy reduces myopia by flattening the central cornea, but the mechanism remains a matter of controversy. In this article, we studied the biomechanical behavior of the cornea and its response to radial keratotomy. METHODS: A human cadaver eye model without corneal epithelium was used in this study. We studied the effects which varying intraocular pressure (IOP) and corneal hydration would have on the keratometric power of unoperated eyes and eyes following radial keratotomy. For nonoperated eyes, first, normal corneal hydration was maintained while the IOP was varied. Second, the IOP was maintained at a constant level of 20 mm Hg while the corneal hydration was changed. The effects of separately varying the IOP and corneal hydration of postoperative eyes following an eight-incision radial keratotomy were studied in a similar fashion. RESULTS: In the nonoperated eye, a very high IOP was associated with a general reduction of corneal astigmatism without significantly affecting the overall keratometric spherical equivalent refraction. A steepening change of less than 0.50 diopters (D) was obtained in all eyes when dehydrating the cornea from 700 +/- 50 microns (centrally) and 830 +/- 70 microns (peripherally), to 495 +/- 25 microns (centrally) and 655 +/- 45 microns (peripherally). Following radial keratotomy, changes in IOP within the physiological range were found to have minimal influence (< 0.50 D) on the radial keratotomy keratometric power. However, after hydrating the cornea with balanced salt solution for 30 minutes, we obtained a mean flattening of 10.00 D. When dehydrating these corneas with topical hyperosmotic solution over a period of 3.5 hours, the flattening reversed to near preoperative values. The change in keratometric power resulting from radial keratotomy was significantly modulated by varying the hydration state of the deepithelialized cornea: the greater the hydration, the flatter the central cornea; therefore, the unpredictable surgical outcomes and diurnal fluctuations observed after radial keratotomy may be affected by applying topical hyperosmotic agents. CONCLUSIONS: We hypothesize that the corneal stroma is an inelastic, anisotropic, layered collagen structure that distributes tensile stress unequally throughout its thickness as a function of the amount of hydration. IOP, within physiological levels, did not have a significant effect on corneal flattening.
Refractive stability after cataract extraction using a 6.5-millimeter scleral pocket incision with horizontal or radial sutures.
Werblin TP
J Refract Corneal Surg · 1994 · PMID 7522091
BACKGROUND: Radial suturing of 6.5-millimeter scleral tunnel incisions following cataract surgery can create significant with-the-rule astigmatism in the immediate postoperative period. Because of the significant visual...
BACKGROUND: Radial suturing of 6.5-millimeter scleral tunnel incisions following cataract surgery can create significant with-the-rule astigmatism in the immediate postoperative period. Because of the significant visual distortion and slow visual recovery seen with radial suturing, this study was undertaken to compare two other suturing techniques which induce lesser amounts of with-the-rule astigmatism in the immediate postoperative period. METHODS: The refractive behavior of eyes closed with loose radial sutures and with horizontal sutures was compared to the behavior of eyes closed with the more traditional "tight" radial sutures following phacoemulsification surgery. RESULTS: Eyes sutured with loosely tied radial sutures demonstrated minimal with-the-rule cylinder immediately following surgery (1.25 D) and showed a more rapid stabilization of astigmatism than did the eyes tied with tight radial sutures, 2 months versus up to 6 months. However, the eyes tied with horizontal sutures, which showed no induced with-the-rule astigmatism at the time of surgery, showed even more rapid stabilization between 5 days and 1 month from the time of surgery. CONCLUSION: To get the most rapid visual rehabilitation following cataract surgery, a wound closure which generates no induced with-the-rule cylinder such as horizontal sutures would be required.
Evaluation of night vision disturbances.
Florakis GJ, Jewelewicz DA, Michelsen HE … +1 more , Trokel SL
J Refract Corneal Surg · 1994 · PMID 7522090
BACKGROUND: Evaluation of night vision disturbances has relied on subjective responses. We designed a test to more objectively measure night vision disturbances. METHODS: The test consisted of projecting a small circle o...
BACKGROUND: Evaluation of night vision disturbances has relied on subjective responses. We designed a test to more objectively measure night vision disturbances. METHODS: The test consisted of projecting a small circle onto a visual acuity screen. The patient is asked to draw exactly what he sees on an Amsler grid. We evaluated 118 eyes in photopic and scotopic conditions and under different conditions of refractive correction. RESULTS: Image degradation increased in scotopic conditions for myopes (p = .0001), hyperopes (p = .005), and emmetropes (p = .01). Myopic refractive error correlated with size of glare response (p = .001). Astigmatism correlated with decentration of glare response (p = .0001). Decentration increased in scotopic compared to photopic conditions (p = .002). CONCLUSION: Our test offers a simple, convenient way to evaluate night vision disturbances and may offer a means of assessing night vision disturbances in patients considering refractive surgery.
Induction of astigmatism by straight transverse corneal incisions, 45 degrees long, at different clear zones in human cadaver eyes.
Sabates MA, Buzard KA, Friedlander MH … +1 more , Cortinas MB
J Refract Corneal Surg · 1994 · PMID 7522089
BACKGROUND: Two of the major factors affecting the amount of astigmatism correction are the length of the transverse incision and its distance from the center of the cornea. Many nomograms used in clinical practice have...
BACKGROUND: Two of the major factors affecting the amount of astigmatism correction are the length of the transverse incision and its distance from the center of the cornea. Many nomograms used in clinical practice have been created by varying the length or clear zone diameter of the incisions. A simplification of this situation has been suggested by Thornton, who has theorized that straight transverse incisions, subtending 45 degrees of arc, have equal astigmatic corrective effect at different clear zones. Our study tested Thornton's theory in human donor eyes. METHODS: Ten eyes were tested at four clear zones: 5.0, 6.0, 7.0, and 8.0 mm. Paired straight transverse incisions, subtending an arc of 45 degrees (2.1 to 3.3 mm long), were centered on the 90-degree meridian. Preoperative keratometric readings at the 180- and 90-degree meridians were compared to the postoperative readings; the difference was the total astigmatism induced. We also calculated the coupling ratio. RESULTS: Student's t-tests comparing clear zones 6.0 and 7.0 mm revealed a statistical difference (p = .0085) in total astigmatic induction, greater for the 6.0-millimeter zone. The coupling ratio decreased as the clear zone diameter increased, presumably as a result of diminished flattening effect along the incised meridian. One-way analysis of variance indicated that the groups were different (p = .0001), and that the theory noted above was incorrect. CONCLUSIONS: The effect of transverse incisions subtending the same angular length, drops off dramatically with clear zones larger than 6.0 mm, contrary to the theory of Thornton. This effect may be due to reduction in coupling as the clear zone diameter increases, suggesting that the greatest efficacy is achieved for transverse incisions placed between 5.0- and 6.0-millimeter zones.
Effect of nitrogen flow on recovery of vision after excimer laser photorefractive keratectomy without nitrogen flow.
Maguen E, Nesburn AB, Papaioannou T … +3 more , Salz JJ, Macy JI, Warren C
J Refract Corneal Surg · 1994 · PMID 7522088
BACKGROUND: Excimer laser (VISX) photorefractive keratectomy was performed using nitrogen flowing through the ocular fixation ring. It was felt that eliminating nitrogen flow may provide faster early visual rehabilitatio...
BACKGROUND: Excimer laser (VISX) photorefractive keratectomy was performed using nitrogen flowing through the ocular fixation ring. It was felt that eliminating nitrogen flow may provide faster early visual rehabilitation. METHODS: Two groups of 50 consecutive eyes underwent photorefractive keratectomy with (N2 flow) and without (no N2 flow) nitrogen flow, and were evaluated at 1 month postoperatively. RESULTS: There were more under- or overcorrections exceeding 1.00 diopter (D) in the N2 flow than in the no N2 flow groups. Eighteen eyes in the N2 flow and 11 in no N2 flow groups saw 20/50 or less, without correction. Fourteen eyes in the N2 flow and nine eyes in the no N2 flow groups lost two or more lines of best spectacle-corrected visual acuity. Four eyes in the N2 flow and none in the no N2 flow groups increased more than 1.00 D of astigmatism. CONCLUSION: The elimination of nitrogen flow in photorefractive keratectomy performed with the VISX laser appears to improve visual results in the early postoperative period.
Financial implications of excimer laser phototherapeutic keratectomy.
Moretti M
J Refract Corneal Surg · 1994 · PMID 7522087
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Laser corneal surgery. Bibliography.
J Refract Corneal Surg · 1994 · PMID 7517323
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Phototherapeutic keratectomy in the treatment of corneal scarring from trachoma.
Goldstein M, Loewenstein A, Rosner M … +2 more , Lipshitz I, Lazar M
J Refract Corneal Surg · 1994 · PMID 7517322
Trachoma is still one of the world's major blinding diseases. Characteristically, trachoma causes deep scarring of the conjunctiva and tarsus that can result in tear deficiency, trichiasis, and entropion. Another common...
Trachoma is still one of the world's major blinding diseases. Characteristically, trachoma causes deep scarring of the conjunctiva and tarsus that can result in tear deficiency, trichiasis, and entropion. Another common finding is a diffused corneal opacity that is the end stage of peripheral and central corneal infiltrates. The conventional treatment of the corneal opacities is keratoplasty, which has a guarded prognosis because of severe dryness and trichiasis. We report on our experience in treating patients with corneal trachoma with phototherapeutic keratectomy (PTK) with the excimer laser.
Use of topical nonsteroidal anti-inflammatory drugs after photorefractive keratectomy.
Ferrari M
J Refract Corneal Surg · 1994 · PMID 7517321
BACKGROUND: Photorefractive keratectomy (PRK) requires a careful pharmacologic regimen during the postoperative period to reduce corneal haze and refractive myopic regression. Noncorticosteroidal anti-inflammatory drugs...
BACKGROUND: Photorefractive keratectomy (PRK) requires a careful pharmacologic regimen during the postoperative period to reduce corneal haze and refractive myopic regression. Noncorticosteroidal anti-inflammatory drugs limit postablative corneal inflammation without the complications that may occur during corticosteroid treatment. METHODS: Twenty consecutive eyes of 10 patients with attempted correction ranging from 4.00 to 9.00 D of myopia were studied. During the postoperative period, corticosteroid drops (dexamethasone 0.1%) were instilled in the first eye of each patient, and the second eye was treated with diclofenac sodium ophthalmic solution 0.1% (Voltaren). Follow-up was 12 months after surgery. RESULTS: Corneal haze and refraction were studied. Six of the 10 eyes treated with noncorticosteroidal anti-inflammatory drugs did not show any significant difference in corneal haze and refractive evolution compared to the contralateral eyes treated with corticosteroids. Two eyes (20%) showed less corneal haze and more refractive stability than the contralateral eyes. In two eyes (20%), we observed similar corneal haze but more refractive regression than in the contralateral eyes. CONCLUSIONS: Eyes treated with topical diclofenac sodium had a similar postoperative course as those treated with corticosteroids, but without the adverse effects of corticosteroids. Topical nonsteroidal anti-inflammatory drugs are represented by diclofenac (Voltaren), which has significant ocular penetration. This permits reduction of the possibility of general and ocular complications that frequently occur with corticosteroids. The aim of this study was to evaluate the efficacy of topical nonsteroidal antiinflammatory drugs vs. corticosteroidal eyedrops after photorefractive keratectomy (PRK) to reduce moderate and high myopia.
Photorefractive keratectomy for the treatment of myopia after epikeratoplasty: a case report.
Loewenstein A, Lipshitz I, Lazar M
J Refract Corneal Surg · 1994 · PMID 7517320
An aphakic eye with a +9.00 diopter (D) refraction developed high myopia of -13.00 D after applying epikeratoplasty using a +14.00 D lenticule. We preformed photorefractive keratectomy by excimer laser. The procedure was...
An aphakic eye with a +9.00 diopter (D) refraction developed high myopia of -13.00 D after applying epikeratoplasty using a +14.00 D lenticule. We preformed photorefractive keratectomy by excimer laser. The procedure was uneventful, with no postoperative pain. Epithelialization occurred as usual. Recovery of the cornea followed the usual course with initial overcorrection followed by certain regression. After 7 months follow-up the spherical equivalent was -3.25 D and the lenticule was clear. In myopia after epikeratoplasty photorefractive keratectomy is an effective alternative to lenticule exchange.
Astigmatic keratotomy followed by photorefractive keratectomy in the treatment of compound myopic astigmatism.
Lipshitz I, Loewenstein A, Lazar M
J Refract Corneal Surg · 1994 · PMID 7517319
Eleven eyes of 9 patients that had compound myopic astigmatism were treated by astigmatic keratotomy followed 1 month later by photorefractive keratectomy (PRK). In 9 eyes arcuate incisions were performed, in 1 eye a mod...
Eleven eyes of 9 patients that had compound myopic astigmatism were treated by astigmatic keratotomy followed 1 month later by photorefractive keratectomy (PRK). In 9 eyes arcuate incisions were performed, in 1 eye a modified Ruiz procedure was performed, and in 1 eye radial T cuts were done. The mean spherical equivalent was -8.26 +/- 2.51 diopters (D) after the astigmatic keratotomy but before photorefractive keratectomy, and -0.36 +/- 0.93 D after photorefractive keratectomy. The mean cylinder was -3.11 +/- 1.16 D preoperatively, and -0.14 +/- 0.9 D postoperatively. Combined astigmatic keratotomy and photorefractive keratectomy are effective treatments for compound myopic astigmatism.
Discrimination between the origins and functional implications of haze and halo at night after photorefractive keratectomy.
O'Brart DP, Lohmann CP, Fitzke FW … +4 more , Klonos G, Corbett MC, Kerr-Muir MG, Marshall J
J Refract Corneal Surg · 1994 · PMID 7517318
A series of 84 eyes with up to -6.00 diopters (D) of myopia were treated by photorefractive keratectomy (PRK) using a 5.00 mm ablation zone. Three months postoperatively, 43 eyes (51%) complained of disturbed night visio...
A series of 84 eyes with up to -6.00 diopters (D) of myopia were treated by photorefractive keratectomy (PRK) using a 5.00 mm ablation zone. Three months postoperatively, 43 eyes (51%) complained of disturbed night vision, compared to 12 (14%) preoperatively. Ten (12%) had significant problems, ie, interference with driving at night. At 12 months, there were 32 patients (38%) with minor disturbances of night vision, 4 (5%) with significant problems.
Holmium:YAG laser thermokeratoplasty for hyperopia.
Durrie DS, Schumer DJ, Cavanaugh TB
J Refract Corneal Surg · 1994 · PMID 7517317
Holmium:YAG laser thermokeratoplasty (LTK), a procedure using a solid-state infrared laser to treat hyperopia, was performed on 10 patients in phase I and 16 patients in phase II--in a total of 29 eyes at the Hunkeler Ey...
Holmium:YAG laser thermokeratoplasty (LTK), a procedure using a solid-state infrared laser to treat hyperopia, was performed on 10 patients in phase I and 16 patients in phase II--in a total of 29 eyes at the Hunkeler Eye Clinic. Phase II was redesigned after phase I results showed undercorrection and regression. The follow-up period ranged from 1 to 24 months (mean 10.9 months). A total of 79% of phase II patients were within +/- 1.00 D of intended correction at the 6-month visit. Looking at both phases together, no patients had J2 or better near vision preoperatively, but 75% had J2 or better at the 6-month visit. A total of 43% of eyes in phase II lost 1 line and 7% lost two lines of best spectacle corrected visual acuity due to induction of irregular astigmatism. The surgical challenges are to insure appropriate centration of the procedure about the optical axis. Concerns about regression and stability will be defined as these patients are followed through their 2-year visits.
Scraping of epithelium for treatment of undercorrection and haze after photorefractive keratectomy.
Loewenstein A, Lipshitz I, Lazar M
J Refract Corneal Surg · 1994 · PMID 7517316
We report an easy, safe technique to treat regression and haze after excimer laser photorefractive keratectomy (PRK), in which the hyperplastic epithelium is removed manually. The results of scraping of epithelium in 21...
We report an easy, safe technique to treat regression and haze after excimer laser photorefractive keratectomy (PRK), in which the hyperplastic epithelium is removed manually. The results of scraping of epithelium in 21 eyes of 20 patients are presented. Mean follow-up time was 3 months (range 1 to 7). The mean spherical equivalent refraction before photorefractive keratectomy was -9.93 +/- 2.95 diopters (D); the mean spherical equivalent refraction before epithelial scraping was -3.82 +/- 2.87 D; after scraping it declined to -2.63 +/- 4.04 D. The uncorrected visual acuity after scraping was 20/50 or better in 6 eyes. In 5 others it was between 20/60 and 20/100, and in 10 eyes it was worse than 20/100. The corrected visual acuity after scraping was 20/30 or better in 8 eyes, between 20/40 and 20/60 in 8 eyes, and between 20/60 and 20/100 in 5 eyes.
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