Journal of refractive and corneal surgery Impact Factor & Information

Publisher: International Society of Refractive Keratoplasty

Journal description

Discontinued in 1994. Continued by the Journal of Refractive Surgery (1995) (1081-597X).

Current impact factor: 0.00

Impact Factor Rankings

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5-year impact 0.00
Cited half-life 0.00
Immediacy index 0.00
Eigenfactor 0.00
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Other titles Journal of refractive and corneal surgery
ISSN 1081-0803
OCLC 30372788
Material type Periodical
Document type Journal / Magazine / Newspaper

Publications in this journal

  • Journal of refractive and corneal surgery 01/1998; 10(4):466. DOI:10.1016/S0161-6420(98)93055-X
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    ABSTRACT: The possible endothelial damage induced by photorefractive keratectomy was investigated in myopic eyes. A morphometric analysis of the endothelial cells was performed in 19 patients before and 2 months after photorefractive keratectomy for the correction of various degrees of myopia. Central ultrasonic pachometry was also recorded at the same examination times. No significant changes (p = .816) of the endothelial cell density were found between preoperative and postoperative measurements. The pleomorphic index did not show any significant changes after treatment (p = .955). Central corneal thickness was reduced to a various extent (range from 50 microns to 250 microns) according to the amount of myopic correction intended. Our preliminary data suggest that photorefractive keratectomy for the correction of myopia does not induce endothelial cell damage, at least in the short term.
    Journal of refractive and corneal surgery 03/1994; 10(2):137-41.
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    ABSTRACT: To date, there has been no systematic study of the effects of ablation zone diameter on the outcome of photorefractive keratectomy. To address these issues, we examined a series of eyes with bilateral corrections using different-sized ablation zones. Thirty-three patients underwent bilateral photorefractive keratectomy (Summit Excimed UV200, Waltham, Mass) with identical dioptric corrections in both eyes, except first eyes had 4.00-millimeter and second eyes had 5.00-millimeter ablation zones. Identical postoperative eyedrop regimens were used in both eyes of each subject and the interval between treatments was 12 months. The mean depth of the programmed central ablation was 24 microns in eyes treated with 4.00-millimeter and 39 microns with 5.00-millimeter zones. There was no statistically significant difference in the preoperative refraction between first and second eyes. Mean changes in refraction at 1, 3, 6, 9, and 12 months were significantly greater in eyes treated with 5.00-millimeter ablation diameters (p < .001). No eyes treated with 4.00-millimeter zones were overcorrected, but five eyes (15%) treated with 5.00-millimeter beams had a refraction greater than +1.00 diopter (D) at 12 months postoperatively. There was no significant difference in the amount of anterior stromal haze between the two eyes at any stage. In 14 patients, less night halo was noticed in the eye treated with a 5.00-millimeter zone. Using a computer program, halo measurements were made in both eyes of 12 patients whose pre- and postoperative refractions were within 0.50 D. The magnitude of halo was significantly less in eyes treated with 5.00-millimeter zones (p < .01). Despite greater depths of stromal ablation with 5.00-millimeter diameters, there was no increased anterior stromal haze or postoperative regression of refraction. The biological and physical constraints governing the optimum size of the photorefractive keratectomy ablation zone are discussed.
    Journal of refractive and corneal surgery 03/1994; 10(2):87-94.
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    ABSTRACT: Studies of corneal power changes resulting from photorefractive keratectomy generally rely on keratometer or videokeratograph measurements. These instruments convert corneal radius of curvatures values to optical powers by means of the single refracting surface formula, which incorporates an index of refraction value of 1.3375. This index approximates that of the tears but not the 1.376 index of the corneal epithelium or stroma. A hypothetical optical model was used to determine the most appropriate index to be chosen with respect to corneal power calculations relative to photorefractive keratectomy. The contribution of each refractive element in the tear lens-corneal surface to the total power of the eye was calculated in order to identify which index of refraction was most appropriate for the corneal power calculation. The outer tear surface has significant optical power but the tear layer as a whole has nearly zero power due to the offsetting negative power of the posterior test surface. There is no significant difference in the effective power of light leaving the corneal anterior surface when considered with or without the tear layer. Photorefractive keratectomy changes the epithelium and anterior surface of the corneal stroma, but does not affect the posterior stroma or other ocular media. Hence the refractive index for the corneal epithelium or stroma of 1.376 should be used in converting radius to optical power values. The error in assuming a corneal index of 1.3375 is a constant proportion equal to 11.4% of the corneal power reading. Photorefractive keratectomy presents a situation in which the actual corneal refractive index of 1.376 should be used for correct corneal radius to power conversions. This may be accomplished by changing the index value in the instrument algorithm for keratometry and videokeratography to 1.376 or by adding a correction factor of either 11.4% of the regular reading to its value or multiplying by the factor 1.114. In other applications of keratometry or videokeratography, the index 1.3375 may be more appropriate.
    Journal of refractive and corneal surgery 03/1994; 10(2):125-8.
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    ABSTRACT: To date, Snellen visual acuity and postoperative refraction have been used to evaluate the results of photorefractive keratectomy. However, other parameters, such as contrast sensitivity function and glare, may be affected by refractive surgery and lead to unsatisfactory visual performance. This prospective study is aimed at evaluating the effect of photorefractive keratectomy on contrast sensitivity function and glare. Static contrast sensitivity function, dynamic contrast sensitivity function, and glare sensitivity were evaluated in 22 myopic eyes before as well as 1, 3, and 6 months after photorefractive keratectomy. The eyes tested were divided into three groups, according to the amount of myopia: group I, from -4.00 to -8.00 diopters (D); group II, from -8.25 to -11.00 D; group III, from -11.25 to -20.00 D. Both static and dynamic contrast sensitivity function at the intermediate spatial frequencies were altered at 1 month after photorefractive keratectomy, with a trend toward recovery at 3 and 6 months postoperatively. Glare sensitivity was not significantly affected by surgery. Contrast sensitivity function and glare testing may show abnormalities in the presence of optimal visual and refractive results. These tests may result especially important for the evaluation of new refractive surgical procedures.
    Journal of refractive and corneal surgery 03/1994; 10(2):129-36.
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    ABSTRACT: We present 3 eyes that underwent photorefractive keratectomy (PRK) for residual myopia after penetrating keratoplasty, and 1 eye that was treated for recurrent granular dystrophy and myopia following penetrating keratoplasty. The 3 refractive eyes experienced improvements in visual acuity and refractive error through 3 months postoperative, but exhibited regression of effect after 6 months postoperative. One eye also exhibited substantial corneal haze at three months postoperative that was not responsive to steroid retreatment. The eye with granular dystrophy obtained symptomatic relief as well as improvement in vision. We tentatively conclude that the corneal transplant reacts to photorefractive keratectomy in much the same way as a normal cornea. Eyes with substantial degrees of post-graft myopia exhibit regression of refractive effect, much like high myopes following primary photorefractive keratectomy. Photorefractive was unable to prevent the recurrence of granular dystrophy in the transplanted tissue. The eyes reported here achieved only modest long-term visual and refractive improvements.
    Journal of refractive and corneal surgery 01/1994; 10(2 Suppl):S206-10.
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    ABSTRACT: Photorefractive keratectomy (PRK) was performed on 98 consecutive normal myopic eyes with the Summit OmniMed laser System. The minimum follow-up was 3 months and 31 were followed for 6 months. Preoperative myopia ranged from -1.25 to -12.00 D. The myopic eyes were divided into 4 groups according to the amount of myopia: group 1 (-1.25 to -3.00 D), 17 eyes; group 2 (-3.12 to -6.00 D), 42 eyes; group 3 (-6.12 to -9.00 D), 29 eyes and group 4 (> 9.00 D), 10 eyes. In group 1 mean uncorrected visual acuity was 0.87 at 3 months, 1.0 at 6 months and all of the eyes were within 0.50 D of the attempted correction. In group 2 mean uncorrected visual acuity was 0.76 at 3 months, 0.87 at 6 months and 92.3% of the eyes were within 0.50 D of the attempted correction. In group 3 mean uncorrected visual acuity was 0.65 and 0.66 at 3 and 6 months respectively and 77.8% of eyes were within 0.50 D of the attempted refractive correction. In group 4, mean uncorrected visual acuity was 0.46 and 0.7 at 3 and 6 months, respectively, and 100% were within 0.50 D of the attempted correction. Two eyes lost 2 lines and 4 eyes gained 2 or more lines of their preoperative best spectacle corrected visual acuity. Three eyes exhibited steroid induced rise in intraocular pressure that was controlled with topical timolol. No serious complications occurred. Despite the short follow-up, photorefractive keratectomy with the 193 nm excimer laser appears to be an effective and safe treatment for the correction of myopia.
    Journal of refractive and corneal surgery 01/1994; 10(2 Suppl):S231-4.

  • Journal of refractive and corneal surgery 01/1994; 10(5):587-8.

  • Journal of refractive and corneal surgery 01/1994; 10(1):34-5.
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    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.
    Journal of refractive and corneal surgery 01/1994; 10(6):621-4.

  • Journal of refractive and corneal surgery 01/1994; 10(6):658.
  • G Simon · Q Ren ·
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    ABSTRACT: 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. 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. 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. 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.
    Journal of refractive and corneal surgery 01/1994; 10(3):343-51; discussion 351-6.
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    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.
    Journal of refractive and corneal surgery 01/1994; 10(6):631-9.
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    ABSTRACT: To compare the levels of prostaglandin E2 (PGE2) in corneal tissue after 193-nanometer excimer laser keratectomy and mechanical keratectomy with a microkeratome. Four rabbits underwent 193-nanometer excimer laser phototherapeutic keratectomy on one eye, and lamellar keratectomy with the microkeratome on the fellow eye. The corneas were harvested at 10 hours after the treatment and quantitated for PGE2 levels using an enzyme-linked immune assay. Control levels of PGE2 in untreated corneas were obtained from a previous study. Unoperated control corneas had low levels of PGE2 (1.79 +/- 1.0 pg/mL). Both surgical techniques resulted in a significant (p < .01) increase in PGE2. Corneas ablated mechanically with the microkeratome had an average PGE2 level of 15.48 +/-5.36 pg/mL, which represented an 8.6-fold increase compared to control; there was an additional 330% mean increase in PGE2 concentration in the laser-ablated corneas (51.29 +/- 36.08 pg/mL) compared to the corneas treated with mechanical lamellar keratectomy (p = .014). Mechanical and photochemical superficial keratectomies induce production of an inflammatory mediator, PGE2. The 193-nanometer excimer laser irradiation causes a greater increase of PGE2 production in the corneal tissue than does keratectomy with the microkeratome; this observation may support a role for cyclo-oxygenase inhibitors in postoperative therapy.
    Journal of refractive and corneal surgery 01/1994; 10(4):413-6.
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    ABSTRACT: 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.
    Journal of refractive and corneal surgery 01/1994; 10(2 Suppl):S281.
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    ABSTRACT: 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.
    Journal of refractive and corneal surgery 01/1994; 10(2 Suppl):S274-6.
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    ABSTRACT: Photorefractive keratectomy (PRK) was performed on 91 eyes of 71 patients who had previous radial keratotomy, radial combined with astigmatic keratotomy or astigmatic keratotomy alone (refractive keratotomy). Residual myopia, prior to photorefractive keratectomy, ranged from -1.50 to -8.00 D (mean -3.62) and cylinder from 0 to 2.25 D (mean 0.78). Uncorrected visual acuity was 20/40 or better in 89.7% at one year. At the 12 month follow-up 75.9% of patients were within +/- 1.00 D of intended correction.
    Journal of refractive and corneal surgery 01/1994; 10(2 Suppl):S235-8.
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    ABSTRACT: Sclera is commonly preserved in glycerin or ethanol before being used for ophthalmic surgery. The purpose of this study was to determine the ability of bacteria to survive in sclera preserved in glycerin or ethanol. Fresh sclera was inoculated with Staphylococcus aureus, Streptococcus pneumoniae, or Pseudomonas aeruginosa and transferred to preservative vials containing glycerin, 95% ethanol, or trypticase soy broth (control) and stored at room temperature. Pieces of sclera were removed from preservative at designated intervals over a 14-day period. The sclera was then homogenized, plated on blood agar, and incubated at 37 degrees C. Colonies were counted at 24, 48, and 72 hours. S. pneumoniae, P. aeruginosa, and S. aureus were recovered from glycerin preserved sclera for up to 12 hours, 1.5 days, and 8 days, respectively. No bacteria was recovered from the ethanol preserved sclera. Bacteria cannot be recovered from ethanol preserved sclera but can survive in glycerin preserved sclera for at least 8 days. Ethanol may offer advantages over glycerin as a scleral preservative due to its greater antibacterial activity.
    Journal of refractive and corneal surgery 01/1994; 10(1):38-40.
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    ABSTRACT: To determine if excimer laser myopic ablation with a defocused laser image produces a smoother ablation profile than does focused laser light. An ArF excimer laser was used to ablate a 5.00-diopter myopic correction in test blocks using both a contracting and expanding iris aperture. Defocused ablation was performed using a contracting iris aperture by translating the target away from the laser source. A confocal laser scanning microscope was used to analyze the surface smoothness at 55x and 275x magnifications. The confocal laser scanning micrographs revealed a series of sharply demarcated concentric ridges in the focused ablation, and less prominent, slightly wavy lines in the defocused ablation performed with a contracting aperture. The focused ablation with an expanding aperture also created concentric ridges toward the periphery, but with slightly smoother edges.
    Journal of refractive and corneal surgery 01/1994; 10(1):20-6.
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    ABSTRACT: For the correction of myopia, small amounts of corneal tissue--including corneal nerves--are removed, resulting in flattening of the central cornea. We studied the changes in corneal sensation in five regions of the cornea following photorefractive keratectomy at varying depths. We examined and compared the recovery of sensation in 17 sighted myopic eyes, with preoperative refractive ranges from -1.00 to -7.25 D. Eyes were divided into shallow (0 to 30 microns) or deep (31 to 70 microns) ablation groups depending on the attempted laser correction. Corneal sensation was measured in the central ablated area and the temporal, inferior, nasal, and superior unablated regions preoperatively and at 1, 3, and 6 months postoperatively. Central and inferior sensation were significantly reduced in the deep ablations at 1 month and continued in the central cornea 6 months postoperatively. There were no overall differences in the sensations in the unablated nasal, temporal, and superior regions between either group or over time. There was a significant second order trend (p = .034) in these three regions, indicating a sharper increase in sensation from baseline in the deeper group at 1 month than the gradual upward trend of the shallow group. Corneal sensation of both the central ablated area and the unablated peripheral cornea is decreased after deep anterior stromal excimer laser ablations and does not recover within 1 month. Although the deeper group showed isolated areas in the periphery of significant second order trends in sensation, the overall trends were not large, indicating no significant anesthetic effect. Fluctuations in sensation can be detected in the five regions even 6 months after excimer laser keratectomy. The clinical importance of these data remain to be defined.
    Journal of refractive and corneal surgery 01/1994; 10(4):417-22.