Journal of refractive and corneal surgery
Discontinued in 1994. Continued by the Journal of Refractive Surgery (1995) (1081-597X).
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Journal impact history
|Other titles||Journal of refractive and corneal surgery|
|Document type||Journal / Magazine / Newspaper|
Publications in this journal
Article: Photorefractive keratectomy
- [Show abstract] [Hide abstract] ABSTRACT: Corneal neovascularization is a common clinical entity. Although visual acuity is usually impaired and corneal function compromised, there has been only limited success in the clinical management of this condition. We evaluated the efficacy of laser photocoagulation of neovascularization in the rabbit cornea. New vessel formation was provoked by the placement of sutures in the corneas. Rose bengal was injected intravenously and new vessels in the upper part of the corneas were treated with an argon laser. The lower halves were used as controls. Eighteen rabbits were divided into 2 groups. In group A neovascularization was treated 28 days after suture removal, when corneal inflammation had regressed. In group B treatment was performed 3 days after suture removal, when the cornea still exhibited marked inflammation. Postoperatively, the corneas were studied by slit-lamp microscopy, fluorescein angiography, and light, as well as electron microscopy. In group A, treatment led to the immediate occlusion of the vessels and to their gradual disappearance during the course of 3 months. In group B, no occlusion was seen during the 3-month follow-up period. The main histologic findings in the occluded vessels were endothelial cell disruption and degeneration, and the formation of clots. Our results suggest that argon laser photocoagulation using rose bengal is an effective method of occluding corneal new vessels, providing there is no corneal inflammation at the time of treatment.
- [Show abstract] [Hide abstract] ABSTRACT: Single and double deepening of the peripheral part of radial keratotomy incisions are used to increase the refractive effect. Single peripheral deepening was performed in 52 eyes of 36 patients and double peripheral deepening in 19 eyes of 14 patients who received radial keratotomy. In the single peripheral deepening group, the mean change in refractive power was 4.01 diopters (D); 53.8% of eyes were within +/- 1.00 D of emmetropia; residual myopia was greater than -1.00 D in 46.2% of eyes; 65.4% of eyes achieved an uncorrected visual acuity greater than or equal to 20/40. In the double peripheral deepening group, the mean change in refractive power was 5.07 D; 52.6% of eyes wee within +/- 1.00 D of emmetropia; residual myopia was greater than -1.00 D in 47.4% of eyes; 89.4% of eyes achieved an uncorrected visual acuity greater than 20/40. The difference in mean dioptric change between the standard radial keratotomy groups and the single and double peripheral deepening groups was 0.53 D and 0.47 D, respectively. Considering the limited additional dioptric change compared with the standard radial keratotomy surgical technique and the increased rate of complications, we think that peripheral deepening in radial keratotomy should be avoided.
- [Show abstract] [Hide abstract] ABSTRACT: A free floating cyst in the anterior chamber was observed 10 days after a 35-year-old woman underwent an eight-incision radial keratotomy and two-incision transverse keratotomy of the left eye. A single self-sealing microperforation had occurred on the inferotemporal incision during the initial surgery, which used a two direction incision technique. A free floating cystic structure was first noted by the surgeon 10 days after surgery, when the patient returned for repeated surgery for residual myopia. After 18 months, there was little change in the size or appearance of the cyst. The patient, who was informed of the complication, remained asymptomatic with uncorrected visual acuity of 20/25 + 2 bilaterally. Because of the lack of growth of the cyst, continued observation was chosen instead of surgical removal. The cause of the cyst is unknown. A free floating cyst in the anterior chamber may occur after refractive keratotomy.
Article: Keratoconus in a donor cornea
- [Show abstract] [Hide abstract] ABSTRACT: The purpose of this study is to investigate retrospectively the visual function of eyes 1 year after photorefractive keratectomy. Visual function was assessed in 34 eyes of 22 patients who had undergone excimer laser surgery (Summit Excimed UV200). The mean time after surgery was 12.3 months. Twenty eyes of 20 age-matched normal subjects served as controls. The following tests were used: high and low contrast logMAR visual acuity, Pelli-Robson contrast sensitivity, and straylightmeter scores at 3.5 degrees and 10 degrees. There was a significant difference between scores obtained for the photorefractive keratectomy population and the control (p < .001, ANOVA). Fifty-six percent (18/32) of the excimer treated eyes fell outside the 95% confidence limits of the normal data in at least one test of visual function; 22% (7/32) fell outside in at least 3 out of 5 tests. Some eyes showed reduced visual function 1 year after excimer surgery compared to age-matched normal controls. These deficits can only be detected fully when psychophysical tests in addition to visual acuity are employed.
- [Show abstract] [Hide abstract] ABSTRACT: Treatment of corneal abrasions often involves antibiotic ointment and pressure patching. The corneal abrasions following excimer laser photorefractive keratectomy have been managed with disposable soft contact lenses and diclofenac (Voltaren) eye drops. We report 13 patients with corneal abrasions from trauma or recurrent corneal erosions treated with application of a disposable soft contact lens and instillation of diclofenac and antibiotic eye drops. All 13 patients reported significant pain relief and all abrasions healed within 3 days (most within 24 hours). Two of the recurrent erosion patients suffered subsequent spontaneous abrasions and one of the traumatic abrasion patients developed a possible infectious keratitis which cleared without visual loss. In this small series, the combination of a disposable soft contact lens and the instillation of diclofenac drops provided significant pain relief while the abrasion healed and allowed the patients to function with binocular vision. This treatment regimen offers an alternative to pressure patching in the treatment of corneal abrasions.
Article: Mastel Byron Radial Keratotomy Guide
- [Show abstract] [Hide abstract] ABSTRACT: There are several advantages to implanting a posterior chamber intraocular lens (IOL) in the ciliary sulcus when the lens capsule is absent. I have developed a simple method of fixating an IOL into the ciliary sulcus which does not require different needles, multiple needle passes, scleral dissection, or awkward surgical maneuvers. Thirty eyes were enrolled in this study. All eyes were either aphakic, requiring a secondary lens implantation, or required IOL exchange. The patients were followed for 30 months. Using a single 10-0 double-armed, polypropylene suture, a through-and-through infraciliary scleral pass secured each haptic without tying. The lens was then positioned into the ciliary sulcus and the knots tied outside the eye under direct visualization. This procedure has been used in 30 eyes without erosion of sutures, dislocation or tilting of the IOL, or induced astigmatism. Twenty-one eyes (70%) had spectacle-corrected visual acuity of 20/40 or better. The results of this study demonstrate that posterior chamber transscleral fixated IOLs give improved postoperative visual results.
- [Show abstract] [Hide abstract] ABSTRACT: Refractive error is assessed in the seated position while keratorefractive procedures are performed in the supine position. Since position-induced ocular torsion could yield suboptimal results from improper axis alignment, this study was undertaken to ascertain whether ocular cyclotorsion occurs when a subject moves from a seated to supine position. Fifty eyes of 29 subjects with refractive cylinder greater than 0.50 diopters were enrolled. Refraction was done with a phoropter and the correction was placed in a trial frame using plus cylinder. Astigmatic axis was determined in the seated and supine positions for 32 eyes by utilizing the "rocking the cylinder" technique and for 32 eyes using the Jackson cross cylinder. Both techniques were used for 14 eyes. No statistically-significant difference for cylinder axis measured in the seated versus supine position was observed using the rocking the cylinder (4.3 degrees standard deviation [SD], 3.5 degrees, range 0 degrees to 13 degrees, p = NS) or the Jackson cross cylinder methods (2.3 degrees, SD, 1.9 degrees, range 0 degrees to 7 degrees, p = NS). Approximately 25% of eyes had a change in axis of 7 degrees to 16 degrees. These data suggest that the cylinder axis does not change significantly or predictably when most subjects move from the seated to supine position. The Jackson cross cylinder method seems more accurate and reproducible than the rocking the cylinder technique in determination of astigmatic axis under these circumstances.
- [Show abstract] [Hide abstract] ABSTRACT: Intraocular lens (IOL) decentration and tilt may affect postoperative refractive errors through spherical aberration of the IOL. Through 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. IOL 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. IOL 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.
- [Show abstract] [Hide abstract] ABSTRACT: Laser photothermal keratoplasty has been studied as a potential refractive procedure. The purpose of this study is to investigate the histological response to various laser treatments including geometrical patterns, radiant exposure levels, and pulse numbers. A noncontact laser photothermal keratoplasty system was used in this study. Epithelial and endothelial response to the laser photothermal keratoplasty annulus treatment pattern were studied on an owl monkey model with a 5-millimeter annulus ring pattern, 8 J/cm2, 25 consecutive pulses at 1 Hz. Epithelial and endothelial response to the laser photothermal keratoplasty spot pattern were then studied and compared on cat and rabbit models for safety monitoring. One pulse and five consecutive pulses of eight different radiant exposures (5.00 J/cm2 to 18.01 J/cm2) were applied on each cornea. A cadaver eye model was used to study the collagen shrinkage induced by the laser spot treatment following the same protocol as the cat and rabbit model. Finally, the biological healing response to the laser photothermal keratoplasty treatment with the optimal laser parameters obtained in our experiment was studied on the cat model. Five cats were treated by the laser photothermal keratoplasty procedure with eight spots on a 3-millimeter ring, 15.6 J/cm2, and 1 pulse. Epithelial and endothelial damage were observed after annulus treatment on an owl monkey's cornea at 8 J/cm2, 25 pulses, and after spot treatment on cat and rabbit corneas at 18.01 J/cm2, five pulses. No endothelial damage was observed on cat corneas for the single pulse treatment at 18.01 J/cm2. For the tissue shrinkage study, no laser photothermal keratoplasty lesion could be detected for a radiant exposure setting below 10.26 J/cm2. Histological cross-sections showed that the five-pulse treatment reached the endothelial layer at a radiant exposure of 13.4 J/cm2, while no single pulse treatment reached the endothelium for the radiant exposure range (5 J/cm2 to 18 J/cm2) studied. The cat model showed that the laser-induced mechanical octagonal stress-lines by collagen shrinkage were maintained after 3 months. The histological sections across the lesion showed a denser keratocyte population indicating scar formation. The volume of collagen shrinkage, its location, and its geometrical shape can be accurately and precisely controlled by a 2.10-micrometer Ho:YAG laser coupled to an optical delivery system.
- [Show abstract] [Hide abstract] ABSTRACT: 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. 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. 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. 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.
- [Show abstract] [Hide abstract] ABSTRACT: Individual clinical and optical variables may influence the effect of excimer laser photorefractive keratectomy. A theoretical model to describe the influence of initial corneal power, astigmatism, and topography on the expected results of photorefractive keratectomy would be useful in identifying those variables that may ultimately improve the predictability of the procedure. Using a mathematical analysis based on the change in sagittal depth of the central ablation zone following photoablation, we predict the effect of initial corneal curvature on the ultimate outcome of a standardized photorefractive keratectomy. Refractive results from the Phase III US Food & Drug Administration clinical trials of photorefractive keratectomy were analyzed to confirm these mathematical predictions. We find that the initial corneal power, theoretically, is not expected to significantly affect the refractive change that results from a given ablation. Similarly, the corneal astigmatism present before photorefractive keratectomy is expected to be only minimally altered by a spherical excimer laser treatment. Clinically, there is no detectable difference in predictability of the procedure amongst groups stratified by initial mean keratometric power. Our analysis provides a methodology to predict the optical effects of photorefractive keratectomy upon the cornea and may be applied to a variety of hypothetical clinical settings. The predicted lack of clinical association between initial corneal curvature and predictability of photorefractive keratectomy is confirmed.
- [Show abstract] [Hide abstract] ABSTRACT: Many radial keratotomy surgeons advocate bilateral simultaneous surgery, in which there is an inherent, although rare, risk of bilateral sight-threatening complications such as microbial keratitis. This study was designed to evaluate the refractive outcomes of simultaneous and non-simultaneous radial keratotomy performed by a single surgeon. We retrospectively compared the results of radial keratotomy performed simultaneously (both eyes operated on the same day, 20 patients) versus non-simultaneously (right and left eyes operated on different days, 71 patients) by a single surgeon. Both eyes had the same surgical procedure, including clear zone diameter and number of incisions. The refractive results of bilateral simultaneous and non-simultaneous surgery were largely equivalent for all parameters analyzed except one. The variability of the difference in postoperative refractive error between right and left eyes was less for those patients undergoing simultaneous surgery (p = .0008). Our data suggest that performing radial keratotomy as a bilateral simultaneous procedure increases the symmetry of the refractive effect. In view of recent reports of sight-threatening risks such as bilateral microbial keratitis following bilateral keratotomy, however, the potential risks and benefits of bilateral surgery should be carefully considered before operating on both eyes on the same day.
- [Show abstract] [Hide abstract] ABSTRACT: 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. 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. 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. This technique offers a viable alternative to transscleral fixation of a posterior chamber IOL via a limbal approach.
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