Journal Of Refractive And Corneal Surgery[JOURNAL]
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105 papers
Retrospective comparison of simultaneous and non-simultaneous bilateral radial keratotomy.
Moreira H, Kolahdouz-Isfahani AH, Englanoff JS … +4 more , Fasano AP, Ziogas A, Villaseñor R, McDonnell PJ
J Refract Corneal Surg · 1994 · PMID 7530104
PURPOSE: 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 wa...
PURPOSE: 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. METHODS: 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. RESULTS: 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). CONCLUSION: 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.
Astigmatism following photorefractive keratectomy for myopia.
Goggin M, Algawi K, O'Keefe M
J Refract Corneal Surg · 1994 · PMID 7530103
BACKGROUND: Astigmatism 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 componen...
BACKGROUND: Astigmatism 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. METHOD: A 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. RESULTS: Thirty-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. CONCLUSIONS: This observation implies meridional variability in the healing process of the anterior cornea following photorefractive keratectomy.
Noncontact laser photothermal keratoplasty. III: Histological study in animal eyes.
Ren Q, Simon G, Parel JM
J Refract Corneal Surg · 1994 · PMID 7530102
BACKGROUND: 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 pa...
BACKGROUND: 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. MATERIALS AND METHODS: 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. RESULTS: 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. CONCLUSION: 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.
Noncontact laser photothermal keratoplasty. II: Refractive effects and treatment parameters in cadaver eyes.
Simon G, Ren Q, Parel JM
J Refract Corneal Surg · 1994 · PMID 7530101
BACKGROUND: 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 photo...
BACKGROUND: 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. METHODS: 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. RESULTS: 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. CONCLUSIONS: Laser photothermal keratoplasty can acutely steepen and flatten the cornea in human cadaver eyes.
Noncontact laser photothermal keratoplasty. I: Biophysical principles and laser beam delivery system.
Parel JM, Ren Q, Simon G
J Refract Corneal Surg · 1994 · PMID 7530100
BACKGROUND: Thermal 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. MATERIALS AND...
BACKGROUND: Thermal 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. MATERIALS AND METHODS: The 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. RESULTS: A 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. CONCLUSIONS: Noncontact 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.
Excimer laser in situ keratomileusis and photorefractive keratectomy for correction of high myopia.
Pallikaris IG, Siganos DS
J Refract Corneal Surg · 1994 · PMID 7530099
BACKGROUND: The purpose of this research was to study the visual outcome of excimer laser photorefractive keratectomy and laser in situ keratomileusis (LASIK) for the correction of moderate and high myopia. METHODS: Twen...
BACKGROUND: The purpose of this research was to study the visual outcome of excimer laser photorefractive keratectomy and laser in situ keratomileusis (LASIK) for the correction of moderate and high myopia. METHODS: Twenty partially-sighted eyes of 20 patients were divided into two groups, LASIK and photorefractive keratectomy. Ten eyes underwent LASIK and the other 10 photorefractive keratectomy. Follow up was at 1, 3, 6, and 12 months. The LASIK technique included a nasally based, 150 microns thick, 8.0 x 9.0 mm diameter, truncated, disc-shaped corneal flap created with a microkeratome; and the ablation of the stroma with a 193-nanometer ArF excimer laser. The flap was returned to its original position and held in place by apposition. The photorefractive keratectomy technique included mechanical removal of the epithelium and ablation of the stroma with a 193-nanometer ArF excimer laser. RESULTS: LASIK series: One eye had a ruptured globe during the second postoperative month and was excluded from the study. The preoperative spherical equivalent refraction ranged from -10.62 to -25.87 diopters (D). The attempted correction ranged from -8.00 to -16.00 D. Postoperative refraction and corneal topography stabilized between 4 and 12 weeks. Spectacle-corrected visual acuity was within 1 Snellen line of preoperative in all eyes. The refraction in six eyes (66.6%) was within +/- 1.00 D of the intended correction, and in eight eyes was within +/- 2.00 D (88.8%) at 12 months. The mean attempted correction (11.40 +/- 2.60 D) was close to the mean achieved correction at 12 months (11.96 +/- 3.10 D). The mean postoperative refractive astigmatism (1.50 +/- 0.97; range, 0.25 to 3.50 D) was close to the preoperative astigmatism (1.70 +/- 1.15; range, 0 to 3.75 D). Endothelial cell density at 12 months showed an average 8.67% of cell loss. All eyes showed a clear interface. Photorefractive keratectomy series: The preoperative spherical equivalent refraction ranged from -10.75 to -23.12 D. The attempted correction ranged from -8.80 to -17.60 D. Postoperative refraction showed regression throughout the follow-up period, and corneal topography did not stabilize. Spectacle-corrected visual acuity was within 1 Snellen line in eight eyes. Two eyes lost 2 and 3 Snellen lines. One eye was within +/- 1.00 D, and three eyes (30%) were within +/- 2.00 D of the intended correction at 12 months. The achieved correction mean (7.17 +/- 5.29 D) was 61% of the attempted mean (11.72 +/- 2.81 D) at 12 months. The postoperative refractive astigmatism (1.80 +/- 0.95; range, 0.50 to 4.00 D) was very close to the preoperative (1.90 +/- 1.33; range, 0 to 5.00 D). Endothelial cell density showed an average of 10.56% cell loss at 12 months. The mean haze at 12 months was 1.2 (0 to 4 scale). CONCLUSION: LASIK, although more complicated because of the use of a microkeratome, was more effective than photorefractive keratectomy in higher myopes. LASIK created less corneal haze. The refraction was more stable with LASIK in the correction of high myopia. Its predictability was three times that of PRK.
The Hamburger Institute.
Waring GO
J Refract Corneal Surg · 1994 · PMID 7530098
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Misalignment of videokeratoscope produces pseudo-keratoconus suspect.
Silverman CM
J Refract Corneal Surg · 1994 · PMID 7528621
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Optometrists barred from using therapeutic lasers in Georgia.
Tucker RP
J Refract Corneal Surg · 1994 · PMID 7528620
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Photorefractive keratectomy.
Gordon M
J Refract Corneal Surg · 1994 · PMID 7528619
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Frown incision in the cornea.
Pohlhausen EG
J Refract Corneal Surg · 1994 · PMID 7528618
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Radial keratotomy and excimer laser photorefractive keratectomy for the correction of myopia.
Binder PS
J Refract Corneal Surg · 1994 · PMID 7528617
PURPOSE: To compare our current knowledge of the two most common current refractive surgical procedures for the correction of myopia. METHODS: I reviewed the scientific literature and my personal experience with radial k...
PURPOSE: To compare our current knowledge of the two most common current refractive surgical procedures for the correction of myopia. METHODS: I reviewed the scientific literature and my personal experience with radial keratotomy and excimer laser photorefractive keratectomy to compare these two modalities. RESULTS: Both radial keratotomy and photorefractive keratectomy are capable of permanently correcting myopic refractive errors. However, each procedure has its individual advantages and disadvantages, with the greatest concern currently being the effect of wound healing on refractive outcome. The procedures are not mutually exclusive. CONCLUSIONS: Both radial keratotomy and photorefractive keratectomy will be used to surgically correct myopia for the next several years until newer technology is developed to improve the predictability and stability of refractive results currently achieved with each procedure.
Rotating brush for fast removal of corneal epithelium.
Pallikaris IG, Karoutis AD, Lydataki SE … +1 more , Siganos DS
J Refract Corneal Surg · 1994 · PMID 7528616
BACKGROUND: A simple new device is proposed for safe and very fast epithelial removal of the cornea. This is a rotating plastic brush that removes the corneal epithelium within a few seconds under irrigation, without cau...
BACKGROUND: A simple new device is proposed for safe and very fast epithelial removal of the cornea. This is a rotating plastic brush that removes the corneal epithelium within a few seconds under irrigation, without causing any mechanical damage to the stromal surface. METHODS: Comparative SEM and TEM studies on rabbit corneas were carried out following epithelial removal by rotating brush and by a Beaver knife blade. Epithelial removal time and reepithelialization time after photorefractive keratectomy were evaluated in a series of 40 human sighted eyes treated with the brush. RESULTS: The rotating brush-abraded surface was smoother compared to the blade-abraded one. Additionally, the brush provoked no damage to the basal lamina of the rabbit corneal epithelium. In human photorefractive keratectomy, the mean time needed for removal of the corneal epithelium by the rotating brush was only 3 sec (range, 2-5 sec). Reepithelialization time following photorefractive keratectomy did not exceed 3 days. CONCLUSION: Experimental and preliminary clinical studies suggest that the new rotating plastic brush is a safe and fast method for removing the corneal epithelium.
Photoablation of gelatin with the free-electron laser between 2.7 and 6.7 microns.
Jean B, Bende T
J Refract Corneal Surg · 1994 · PMID 7528615
BACKGROUND: Photoablation in the infrared (IR) is an option for future refractive and corneal surgery; its basic principles have not yet been investigated systematically. For the first time, the free electron laser allow...
BACKGROUND: Photoablation in the infrared (IR) is an option for future refractive and corneal surgery; its basic principles have not yet been investigated systematically. For the first time, the free electron laser allows the dynamic study of photoablation over a wide range of wavelengths with variable combinations of pulselength and energy. The goal of this study is to use the free electron laser as a tool to describe photoablation in the IR quantitatively. We studied the function of wavelength as it is related to target material spectroscopy and the effects of corneal hydration and the pulse repetition rate. METHODS: Surface absorption spectroscopy of the human cornea and of gelatin as a proven model of the cornea was performed between 2.7 and 6.7 microns. Gelatin probes of well-defined thickness (140 +/- 5 microns) and controlled hydration (wet/dry weight 1 to 4.5) served as target material. Photoablation was performed with the Vanderbilt University free electron laser (Nashville, Tenn) in September 1992 at a fluence of 1.27 J/cm2, and a macropulse of 4 microseconds, composed of 2 ps micropulses at a 2.9 GHz pulse repetition rate. Wavelength was tunable between 2.7 and 6.7 microns at stable beam profiles. Ablation experiments were performed as a function of energy, hydration, and pulse repetition rate. Ablation rates were assessed by a) perforation experiments, and b) direct measurements using confocal laser topometry (UBM, Ettlingen, FRG). RESULTS: Ablation rate, assessed by perforation experiments and topometry, correlated well with the corresponding measured absorbencies of the target material: maximal ablation rate at maximal target absorption, around the 3- and 6-micrometer water absorption bands. The ablation threshold at 6.2 microns was 0.7 +/- 0.05 J/cm2 (perforation) and 0.55 +/- 0.08 J/cm2 for depth measurements. Ablation rate as a function of hydration increased to 2.3 (wet/dry weight) with a decrease for higher hydrations. Ablation rate as a function of the pulse repetition rate showed an increase of up to 20 Hz, where it was found to be 60% higher. CONCLUSION: The first systematic use of free electron laser technology positively correlated ablation efficiency with target material absorption, thus identifying a "new" promising wavelength at around 6.2 microns for materials with a high water content such as corneal tissue.
Surgical results of penetrating keratoplasty in essential iris atrophy.
DeBroff BM, Thoft RA
J Refract Corneal Surg · 1994 · PMID 7528614
BACKGROUND: Results of penetrating keratoplasty in iridocorneal endothelial syndrome have been considered favorable based on past studies; however, documented results in eyes specifically with essential iris atrophy are...
BACKGROUND: Results of penetrating keratoplasty in iridocorneal endothelial syndrome have been considered favorable based on past studies; however, documented results in eyes specifically with essential iris atrophy are lacking. METHODS: A retrospective study was performed to evaluate all patients at the University of Pittsburgh with essential iris atrophy who had undergone penetrating keratoplasty for corneal decompensation over 21 years (1971-1992). RESULTS: Penetrating keratoplasty had been performed on six eyes with essential iris atrophy for corneal decompensation. All eyes postoperatively had evidence of persistent anterior uveitis resistant to corticosteroid treatment with one or more episodes of graft reaction. Five of the six eyes (83.3%) ultimately went on to graft failure. Two of the six eyes (33.3%) rejected grafts on two separate occasions. CONCLUSIONS: Penetrating keratoplasty in essential iris atrophy was frequently associated with chronic anterior uveitis and immunologic graft failure.
Topical diclofenac following excimer laser: effect on corneal sensitivity and wound healing in rabbits.
Loya N, Bassage S, Vyas S … +3 more , del Cerro M, Park SB, Aquavella JV
J Refract Corneal Surg · 1994 · PMID 7528613
BACKGROUND: Diclofenac is a nonsteroidal antiinflammatory drug (NSAID) that is widely used systemically and topically. We studied the effect of diclofenac on corneal reepithelialization and corneal sensitivity after exci...
BACKGROUND: Diclofenac is a nonsteroidal antiinflammatory drug (NSAID) that is widely used systemically and topically. We studied the effect of diclofenac on corneal reepithelialization and corneal sensitivity after excimer laser treatment in rabbits. METHODS: Twelve New Zealand white rabbits were divided into four groups (A, B, C, and D). Groups A and B received diclofenac four times and eight times daily, respectively, following a central 5-millimeter epithelial debridement. Groups C (control) and D (diclofenac four times daily) underwent excimer laser ablation (30-micrometer depth) following manual debridement. Wound healing was compared between groups A and B and groups C and D. Sensitivity was recorded preoperatively and postoperatively 1 to 5 and 14 days in groups C and D until normal values were reestablished. RESULTS: Total time for corneal wound healing and epithelial migration rates was not delayed in any group receiving diclofenac (A, B, and D). Sensitivity after laser ablation reached a minimum of 15% to 20% in both groups C and D by day 2 and returned to normal (100%) by day 8. The decrease in sensitivity between group C, the controls, and group D, receiving diclofenac four times daily, was not statistically significant. CONCLUSIONS: Diclofenac can be used up to eight times daily in the rabbit without causing changes in corneal wound healing or epithelial migration rate. There was no significant, long-term reduction of sensitivity, and recovery was not affected by diclofenac.
Corneal sensation following excimer laser photorefractive keratectomy in humans.
Ishikawa T, Park SB, Cox C … +2 more , del Cerro M, Aquavella JV
J Refract Corneal Surg · 1994 · PMID 7528612
BACKGROUND: For the correction of myopia, small amounts of corneal tissue--including corneal nerves--are removed, resulting in flattening of the central cornea. METHODS: We studied the changes in corneal sensation in fiv...
BACKGROUND: For the correction of myopia, small amounts of corneal tissue--including corneal nerves--are removed, resulting in flattening of the central cornea. METHODS: 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. RESULTS: 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. CONCLUSIONS: 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.
Prostaglandin E2 production after lamellar keratectomy and photorefractive keratectomy.
Szerenyi KD, Campos M, McDonnell PJ
J Refract Corneal Surg · 1994 · PMID 7528611
PURPOSE: To compare the levels of prostaglandin E2 (PGE2) in corneal tissue after 193-nanometer excimer laser keratectomy and mechanical keratectomy with a microkeratome. METHODS: Four rabbits underwent 193-nanometer exc...
PURPOSE: To compare the levels of prostaglandin E2 (PGE2) in corneal tissue after 193-nanometer excimer laser keratectomy and mechanical keratectomy with a microkeratome. METHODS: 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. RESULTS: 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). CONCLUSIONS: 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.
Nonfreeze myopic keratomileusis for myopia in 158 eyes.
Laroche L, Gauthier L, Thenot JC … +6 more , Lagoutte F, Nordmann JP, Denis P, Borderie V, Giral P, Saraux H
J Refract Corneal Surg · 1994 · PMID 7528610
BACKGROUND: A prospective evaluation of non-freeze myopic keratomileusis is reported. METHODS: One hundred and fifty-eight eyes of 98 consecutive patients underwent nonfreeze myopic keratomileusis, with BKS 1000 (Eyetech...
BACKGROUND: A prospective evaluation of non-freeze myopic keratomileusis is reported. METHODS: One hundred and fifty-eight eyes of 98 consecutive patients underwent nonfreeze myopic keratomileusis, with BKS 1000 (Eyetech-M.V.A.A.G, Balzers, Liechtenstein) refractive set. The preoperative myopia ranged from -6.25 to -28.00 D. Mean follow up was 591.3 days (range, 90 to 1500 days). RESULTS: The logarithmic mean preoperative spectacle-corrected visual acuity was 0.48 +/- 0.31 (20/40), and 0.44 (20/50) +/- 0.30 after 2 years and longer, whereas mean uncorrected visual acuity was 0.32 +/- 0.28 (20/70) in 34 of 82 (41.5%) eyes. After 2 years and longer, 21 of 82 (25.6%) eyes were within 1.00 D of emmetropia, and 43 of 82 (52.4%) were within 2.00 D. The subjective spherical equivalent refraction confidence interval at 90% was 9.28 D (-6.85 to +2.43 D). No refractive instability was detected during follow-up. We detected a trend toward improvement of spectacle-corrected visual acuity with time. However, after 2 years and longer, there was an increase in astigmatism of more than 1.00 D, when compared to the preoperative values, and 14 of 82 (17%) eyes lost two or more lines of spectacle-corrected visual acuity (statistically significant: p < .01). CONCLUSION: The nonfreeze myopic keratomileusis procedure, with BKS 1000, substantially reduces moderate to high myopia, but predictability of refractive outcome is only fair, and the frequency of optical complications including irregular astigmatism is higher than desired.
Summit builds on co-management concept.
J Refract Corneal Surg · 1994 · PMID 7528609
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