Kératotomie radiaire pour le traitement des sous-corrections après le laser excimer, (Radial keratotomy for the treatment of excimer laser undercorrections).
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Cornea↗
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[Correction of astigmatism with the Excimer laser].
Excimer laser corneal T-excisions for the correction of astigmatism in eight eyes followed up for three months postoperatively revealed an effective change in refraction of up to 4.2 diopters. The effect depends on the depth of the excision. Although the clinical results agree with astigmatism theory predictions from a biomechanical model of the cornea, some features are not explained by the model. The temporal behavior of the changes in refraction subsequent to excimer laser excisions differ from those produced by blade incisions, indicating a different repair mechanism. The keratectomy technique employed did not result in any serious side effects.
Adult↗
Percutaneous excimer-laser and excimer-laser-assisted angioplasty of the lower extremities: results of initial clinical trial.
Percutaneous peripheral excimer-laser angioplasty at 308 nm was used for treatment of 30 patients with peripheral vascular disease. Twenty-eight patients underwent laser-assisted balloon angioplasty, and two patients underwent laser angioplasty alone. Acute angiographic and clinical success was achieved in 24 of 31 (77%) femoropopliteal stenoses and occlusions. Seven of nine (78%) stenoses, six of seven (86%) short (0-5 cm) occlusions, seven of eight (88%) medium-length (6-10 cm) occlusions, three of four (75%) long (11-15 cm) occlusions, and one of three (33%) extreme (greater than 15 cm) occlusions were successfully treated. Inability to treat total occlusions was in each case related to a failure to maintain coaxial position and subintimal passage of the fiber. These cases demonstrate the feasibility of safely performing percutaneous peripheral excimer-laser or excimer-laser-assisted angioplasty. The overall frequency of restenosis after a mean follow-up period of 9.1 months was 29%. The data suggest that these procedures may be useful for the treatment of peripheral vascular disease in selected patients.
Adult↗
Undercorrection after excimer laser refractive surgery. Excimer Laser Group.
PURPOSE: The incidence and correlations of undercorrection were studied for 1 year after excimer laser surgery for myopia or myuopic astigmatism. METHODS: A consecutive series of 645 eyes of 440 patients were studied. Eyes were examined preoperatively and at 1, 3, 6, and 12 months after surgery. The parameters evaluated were visual acuity, refraction, and corneal clarity. RESULTS: Following excimer laser surgery, undercorrection of > or = -1.00 diopters gradually increased from 10% at 1 month to 40% at 12 months. Increasing degree of preoperative myopia was significantly associated with increasing occurrence of undercorrection at 3 months (chi 2 = 17.3, P < .001), 6 months (chi 2 = 53.6, P < .001), and 12 months (chi 2 = 64.8, P < .001). Undercorrection was more common in eyes that had had photorefractive keratectomy than in those that had had photoastigmatic refractive keratectomy (odds ratio, 0.40; 95% confidence interval, 0.25 to 0.60). At 1 year, a loss of 2 or more lines of best-corrected visual acuity was recorded in 38% of undercorrected patients. Loss of 2 or more lines of best-corrected visual acuity was more common in patients undercorrected by -1.00 diopter or more (odds ratio, 8.8; 95% confidence interval, 5.4 to 14.6). No relationship was seen between corneal haze and loss of best-corrected visual acuity. Undercorrection was not associated with age, gender, use of nonsteroidal anti-inflammatory drugs, bandage contact lens wear, or corneal haze. Patients with lower degrees of myopia reached a stable refraction more quickly. At 6 months, 71% were within +/- 0.5 diopter of 1-year refraction. Of 17 patients with undercorrection who were treated with topical corticosteroids, only one patient showed a permanent beneficial change. CONCLUSION: Occurrence of undercorrection is more common in patients with severe myopia and when simultaneous astigmatic corrections are undertaken.
Adult↗
[The treatment of myopia by photoreactive keratectomy (PRK) with the 193-nm excimer laser].
Excimer laser photokeratectomy is the most recent procedure used for correcting myopia surgically. It consist in flattening the cornea by performing ablations of a part of its anterior stroma. Over 15,000 patients underwent this almost entirely robotic surgical intervention, supposed not to present the shortcomings of radial keratotomy. This robotic surgery tend to replace radial keratotomy. Photokeratectomy is designed to correct all kinds of myopia, astigmatism as well as these resulting from such surgical interventions as cataract extraction or Keratoplasty. A bifocal photorefractive keratectomy is expected to correct the myopia of the patients who reached the age of presbyopia.
Animals↗
Coronary perforation after excimer laser coronary angioplasty: the Excimer Laser Coronary Angioplasty Registry experience.
OBJECTIVES: This study assessed the frequency of perforation with excimer coronary angioplasty. BACKGROUND: Coronary artery perforation after conventional percutaneous transluminal coronary angioplasty is extremely rare. Because laser coronary angioplasty involves actual tissue ablation, it has an increased potential for perforation. METHODS: All patients in the Excimer Laser Coronary Angioplasty Registry were included in this prospective study. Those who had a perforation related to the procedure were compared with those who did not have this complication. RESULTS: Of 2,759 consecutive patients in the Excimer Laser Coronary Angioplasty Registry, 36 (1.3%) had perforation. In these patients, the left anterior descending coronary artery was the most frequently treated vessel (53%). There were no differences in fiber sizes between patients with and those without perforation. Among the patients with perforation, 36.1% required coronary artery bypass surgery, 16.7% experienced an infarction and 5.6% had a fatal outcome. Among the patients without perforation, the rates were 3.1%, 3.8% and 0.6%, respectively. However, 41.7% of the patients with documented coronary artery perforation did not need coronary artery bypass surgery or experience myocardial infarction or death. No angiographic characteristics distinguished lesions with from those without perforation. The frequency of coronary artery perforation declined over time with increasing operator experience, from 1.6% in the first 1,888 patients to only 0.4% in the last 1,000 patients (p = 0.002). CONCLUSIONS: With increasing operator experience, the rate of perforation with excimer laser coronary angioplasty has decreased. When perforation occurs, subsequent event rates increase.
Angioplasty, Balloon, Coronary↗
Predictability of excimer laser treatment of myopia. Melbourne Excimer Laser Group.
OBJECTIVE: To prospectively examine the predictability of excimer laser photorefractive keratectomy and photoastigmatic refractive keratectomy for myopia that ranged from -1 to -18 diopters (D). METHODS: Patients were treated with an excimer laser and followed up prospectively for 12 months. Low myopia was treated in one ablation zone (6.0 mm), high myopia in two ablation zones (5.0 and 6.0 mm), and extreme myopia in three ablation zones (4.5, 5.0, and 6.0 mm) with a maximum treatment of 15 D. Data were analyzed to determine the distribution of the various postoperative outcomes by preoperative myopia. RESULTS: Two hundred seventy-four low myopes, 189 high myopes, and 41 extreme myopes were available for 12-month follow-up. The re-treatment rate increased with preoperative myopia. The predictability of refraction and uncorrected and best corrected visual acuity progressively decreased with increasing myopia. The likelihood of losing lines of best corrected visual acuity and corneal haze increased with increasing myopia. CONCLUSION: These data should help in the counseling of patients about the likely outcome if they have excimer laser surgery to correct myopia.
Adult↗
Coronary artery perforation during excimer laser coronary angioplasty. The percutaneous Excimer Laser Coronary Angioplasty Registry.
OBJECTIVES: The aim of this study was to analyze the risk of vessel perforation during excimer laser angioplasty. BACKGROUND: Vessel perforation is a serious complication of angioplasty. METHODS: A total of 764 patients had 858 stenoses treated with excimer laser angioplasty. Laser catheters had a diameter of 1.4, 1.7 or 2 mm. Laser energy was delivered in pulses of 135 ns, at a frequency of 25 s-1 and at a fluence of 30 to 60 mJ/mm2. Follow-up angiography was requested for all patients who did not require emergency bypass surgery. RESULTS: In the 764 consecutive patients treated with excimer laser coronary angioplasty, vessel perforation occurred in 23 patients (3%). Nine patients had a major complication resulting directly from vessel perforation (cardiac tamponade, myocardial infarction or need for bypass surgery) and 14 had no clinical complications after successful sealing of the puncture site. No patient with a perforation died. Multivariate analysis showed that bifurcation lesions (odds ratio [OR] = 3.5; p = 0.049), diabetes mellitus (OR = 3.15; p = 0.029) and female gender (OR = 2.86; p = 0.013) were associated with an increased risk of vessel perforation. Lesions > 10 mm in length (OR = 0.45; p = 0.206), calcified stenoses (OR = 0.26; p = 0.088) and saphenous vein graft lesions (OR = 0.50; p = 0.295) were not at increased risk. Vessel perforation was seen in 10 (8.3%) of 120 lesions in which the laser catheter was equivalent in diameter to the target vessel (< or = 0.5 mm smaller in size) but in only 8 (1.5%) of 525 lesions in which the laser catheter was > 1 mm smaller than the target vessel (p = 0.001). CONCLUSIONS: Most lesions thought to be suitable for excimer laser treatment are not at increased risk of perforation. The complication may be avoided by improved patient and laser catheter size selection.
Adult↗
Intraoperative coronary artery endarterectomy with excimer laser.
Compared with continuous-wave lasers, excimer lasers exhibit several in vitro advantages: nonthermal ablation process and linear relation between the number of pulses and the depth of the crater. A 308 nm, 20 nsec pulse duration, 1 to 5 repetition rate laser was specifically designed for clinical application. At the time of cardiopulmonary bypass in 10 symptomatic patients, before bypass grafting, a 1 mm diameter core specifically ultraviolet-tipped fiberoptic scope was introduced via the coronary arteriotomy and placed upstream (seven patients) and downstream (three patients) in contact with the stenosis. Laser power was increasingly delivered up to the clearing of the stenosis or occlusion. Quality of angioplasty was controlled by calibration of the neolumen, cardioplegic solution output through the laser-treated segment, and an eighth day or sixth month coronary arteriogram. In the first three patients studied on the eighth day, all laser-treated coronary artery segments showed an early parallel-linked patent neolumen despite competitive bypass graft flow. In the patients studied after 6 months, all recanalized segments were patent except one; in one patient the venous graft was occluded, but the upstream laser angioplasty was patent. The main limitation of the method lies in the fact that laser coronary recanalization is confined to the fiber core diameter. We conclude that (1) excimer laser angioplasty may be safe and efficient during surgical procedure and (2) as catheter flexibility remains the most critical problem, we are now assuming an appropriate tool with a multifiber system that is suitable for intraoperative as well as percutaneous routes.
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Clinical success, complications and restenosis rates with excimer laser coronary angioplasty. The Percutaneous Excimer Laser Coronary Angioplasty Registry.
The role of excimer laser angioplasty in treating complex coronary artery disease remains uncertain. A randomized trial comparing this new technology with balloon angioplasty cannot be designed until systematic analysis identifies the lesion types that are likely to benefit from treatment with excimer laser angioplasty. In a cohort of 764 patients who had 858 coronary stenoses treated with excimer laser-facilitated angioplasty, relative risk analysis was used to examine acute success, complications and restenosis rates, and the results were compared with those of balloon angioplasty to identify the lesion types that show the greatest benefit with the new treatment. Clinical success was achieved in 657 patients (86%), as indicated by < or = 50% residual stenosis and no in-hospital complication. A major in-hospital complication (death, bypass surgery, or Q-wave or non-Q-wave myocardial infarction) occurred in 58 patients (7.6%). Follow-up angiography was obtained in 70% of eligible patients. Combining angiographic and noninvasive restenosis rates yielded an overall restenosis rate of 46%. Relative risk analysis showed that major complications occurred frequently in lesions at an arterial bifurcation (odds ratio [OR] 5.96 [2.76, 12.6]; p = 0.001). However, certain complex lesions that are difficult to treat with balloon angioplasty (saphenous vein graft lesions, lesions > 10 mm, ostial lesions, calcified stenoses, total occlusions and unsuccessful balloon dilatations), analyzed together as a group, had lower complication rates by univariate (OR 0.59 [0.35, 1.00]; p = 0.051) and multivariate logistic regression (p = 0.006) analyses.(ABSTRACT TRUNCATED AT 250 WORDS)
Angioplasty, Balloon, Coronary↗
Topical interferon alpha 2b for corneal haze after excimer laser photorefractive keratectomy. The Melbourne Excimer Laser Group.
PURPOSE: To determine whether topical interferon alpha 2b (IFN-alpha) prevents corneal haze after excimer laser photorefractive keratectomy (PRK). SETTING: Tertiary referral ophthalmic hospital. METHOD: A prospective, double-blind, placebo-controlled, randomized study of 31 patients was undertaken. After surgery in a single institution, patients received a drop of either a placebo or IFN-alpha (5 x 10(6) IU/ml) four times daily for 4 weeks. The main outcome measures were corneal haze, refraction, and visual acuity. RESULTS: The major side effect of interferon alpha treatment was a significant delay in epithelial healing by a mean of 2 days. The means of the average post-treatment clinical scores for haze in all patients up to 12 months after surgery were 0.46 +/- 0.25 for the IFN-alpha group and 0.64 +/- 0.43 for the placebo group (P = .20). Of patients with a correction of greater than 5.00 diopters (D), the IFN-alpha group had significantly less haze over the course of the study (0.39 +/- 0.23 versus 0.98 +/- 0.50; P = .03). After 12 months, the mean absolute spherical equivalent in the two groups was not significantly different (1.02 +/- 1.13 D versus 1.44 +/- 2.64 D). There was a tendency toward better uncorrected visual acuity in the INF-alpha group (P < .10, Kolmogorov-Smirnov). CONCLUSION: Topical IFN-alpha may merit further investigation as a treatment to reduce corneal haze after excimer laser PRK for corrections greater than 5.00 D.
Administration, Topical↗
Relation of hormone and menopausal status to outcomes following excimer laser photorefractive keratectomy in women. Melbourne Excimer Laser Group.
PURPOSE: To examine the effect of hormone use, pregnancy and menopausal status on clinical outcomes following excimer laser surgery for myopia and myopic astigmatism. METHODS: Participants comprised all female patients of the Melbourne Excimer Laser Group (MELG). A standardised surgical protocol was followed by the 27 MELG members, using the VisX 20/20 excimer laser and included the prospective collection of the following information preoperatively and one, three, six and 12 months after the procedure: uncorrected and best corrected visual acuity with a LogMAR chart; best manifest refraction; and subjective assessment of corneal clarity. A survey that elicited information about oral contraceptive (OC) use, pregnancy history, surgical and natural menopause, and use of hormone replacement therapy (HRT) was mailed to all the women. RESULTS: A 77% response to the mailed survey was achieved. Two women were pregnant at the time of surgery, one became pregnant during the first month after surgery, and all three women were excluded from further analyses, although a review of two of the case histories revealed suboptimal clinical outcomes. Women taking OC were included in the control group after OC use was shown not to be associated with outcome. Women were grouped accordingly: control, n = 225, pre-menopausal on HRT, n = 7, post-menopausal not on HRT, n = 34; and post-menopausal on HRT, n = 21. The groups differed significantly with regard to age and preoperative spherical equivalent. After controlling for age and preoperative spherical equivalent, the mean number of uncorrected LogMAR letters read one year after surgery was significantly lower for the post-menopausal women on the HRT in comparison with the control group. Best corrected acuity and corneal clarity were not significantly different among the groups. DISCUSSION: These preliminary results suggest that the interaction of menopausal and HRT status could decrease the effectiveness of PRK and PARK, but require confirmation with a further study in a prospective manner using objective measures of corneal epithelial healing and serum hormone levels.
Adult↗
Retreatment after excimer laser photorefractive keratectomy. The Melbourne Excimer Laser Group.
PURPOSE: To determine the risk factors for undercorrection of myopia after photorefractive keratectomy and to evaluate the efficacy and safety of retreatment. METHODS: A VISX Twenty/Twenty excimer laser was used to treat myopia and myopic astigmatism of up to -15.00 diopters (spherical equivalent) at the corneal plane. Retreatments were performed primarily for undercorrection with or without coexistent corneal haze or abnormalities on videokeratoscopy. Not every patient who was undercorrected requested retreatment. RESULTS: Of 645 eyes (440 patients) followed up for more than 12 months, 58 eyes (9%) required retreatment. The retreatment rate increased with increasing myopia: 17 (5%) eyes with myopia of less than -5.00 diopters, 30 (13%) eyes with myopia of -5.01 to -10.00 diopters, and 11 (19%) eyes with myopia of greater than -10.00 diopters required a second procedure. A higher retreatment rate was observed after astigmatic corrections than after spherical corrections. Corneal haze after retreatment was no greater than that observed after initial procedures. Twelve months after primary procedures, 378 (75%) of 504 eyes were within 1.00 diopter of emmetropia, whereas 27 (69%) of 39 eyes attained this result after retreatment. A total of 383 (76%) of 504 eyes attained uncorrected visual acuity of 20/40 or better after primary procedures, compared with 25 (64%) of 39 eyes after retreatment. CONCLUSIONS: The risk of undercorrection requiring retreatment after photorefractive keratectomy increases with the magnitude of the primary treatment. Although less successful than initial procedures, retreatment appears to enhance the results of photorefractive keratectomy.
Adult↗
Comparison of excimer laser treatment of astigmatism and myopia. The Excimer Laser and Research Group.
OBJECTIVE: To assess the safety and efficacy of excimer laser treatment of myopic astigmatism and to compare this with the excimer laser treatment of myopia. DESIGN: A prospective, open study of consecutive patients having excimer laser treatment of myopic astigmatism or myopia. SETTINGS: Patients were recruited from 18 private ophthalmic practices. PATIENTS: Fifty-four eyes received treatment for astigmatism and 66 eyes for myopia. One patient was lost to follow-up, and another underwent an ineffective ablation. INTERVENTIONS: A VISX Twenty/Twenty excimer laser was used to perform either photoastigmatic refractive keratectomy or photorefractive keratectomy. MAIN OUTCOME MEASURES: Refraction and visual acuity with and without correction were assessed preoperatively and postoperatively. RESULTS: At 6 months, 17 (85%) of the 20 patients receiving photoastigmatic refractive keratectomy were within 1 diopter of plano refraction, and 19 (95%) of 20 had uncorrected visual acuity of 6/12 (20/40) or better. For patients receiving photorefractive keratectomy, these figures were 28 (88%) of 32 patients and 28 (88%) of 32 patients, respectively. CONCLUSIONS: Excimer laser surgery offers an effective option in the treatment of myopic astigmatism.
Adult↗
Effect of intracoronary saline infusion on dissection during excimer laser coronary angioplasty: a randomized trial. The Percutaneous Excimer Laser Coronary Angioplasty (PELCA) Investigators.
OBJECTIVES: We sought to evaluate whether intracoronary saline infusion during excimer laser coronary angioplasty decreases the incidence of significant laser-induced coronary artery dissections. BACKGROUND: Despite procedural success rates > 90%, coronary artery dissections occur in 17% to 27% of excimer laser coronary angioplasty procedures. Excimer laser irradiation of blood results in vapor bubble formation and acoustomechanical trauma to the vessel wall. Saline infusion into a coronary artery may minimize blood irradiation and consequent arterial wall damage. METHODS: In this prospective, randomized, controlled study, consecutive patients undergoing excimer laser coronary angioplasty were randomly assigned to conventional laser irradiation in a blood medium or to laser irradiation with blood displacement by intracoronary saline infusion. In the patients randomized to intracoronary saline infusion, prewarmed normal saline was injected through the coronary artery guide catheter at a rate of 1 to 2 ml/s using a power injector. The incidence and severity of dissection after excimer laser ablation were evaluated in a core laboratory by angiographers with no knowledge of treatment assignment. The severity of coronary artery dissection was rated on an ordinal scale of 1 to 5. Dissections of grade 2 or higher were considered significant. RESULTS: The mean (+/- SE) dissection grade after laser angioplasty in patients treated with intracoronary saline infusion was 0.43 +/- 0.13 compared with 0.91 +/- 0.26 in patients undergoing laser angioplasty in a blood medium. The incidence of significant dissection was 7% in saline-treated patients compared with 24% in conventionally treated patients (p < 0.05). No significant complications were associated with saline infusion. CONCLUSIONS: Intracoronary saline infusion should be incorporated into all excimer laser coronary angioplasty procedures.
Aged↗
[The Excimer laser. II. Initial experiences with the Excimer laser in Lucerne].
In the period between September 1990 and July 1991, 35 patients (46 eyes) were treated with the Excimer Laser. In 25 patients (34 eyes), a Myopia-Laser-Shaping was performed, one patient was treated for both myopia and astigmatism. In eight patients (10 eyes) correction of astigmatism was carried out. Two patients with recurrent erosions and one patient with superficial scarring of the cornea were treated. The authors review their initial experience with the Excimer Laser. The decision to initiate treatment must not be undertaken lightly, because the possibility of serious complications may not be neglected. This method shows promise in selected patients with light to medium degrees of myopia. In cases of severe myopia, our experience is encouraging. Subjectively, the patients are satisfied with the results, which do not fall short of their expectations. Further research and clinical experience in this area is urgently required.
Astigmatism↗
Astigmatic change 1 year after excimer laser treatment of myopia and myopic astigmatism. Melbourne Excimer Laser Group.
PURPOSE: To evaluate the surgically induced astigmatism (SIA) 1 year after excimer laser photorefractive astigmatic keratectomy (PARK) and photorefractive keratectomy (PRK). SETTING: Royal Victorian Ear and Eye Hospital, Melbourne, Australia. METHODS: This study comprised 333 PARK patients and 155 PRK patients treated with a VISX 20/20 excimer laser and followed prospectively for 12 months. Vector analysis of the change in astigmatism was used to calculate the SIA in the PRK group and the percentage of astigmatism corrected in the PARK group. RESULTS: Among patients with low cylinders astigmatic correction varied greatly, particularly in those treated for large amounts of myopia. The spherical PRK treatments yielded a mean induced postoperative astigmatism of 0.47 diopter. There was a linear relationship between this inadvertent SIA and increasing myopia. CONCLUSION: Excimer laser surgery for myopia creates a low degree of random, unpredictable SIA that may be the result of irregular epithelial thickening during postoperative healing. This creates a background noise of astigmatic change upon which the targeted astigmatic correction is superimposed.
Adult↗
Excimer laser treatment for high and extreme myopia. The Melbourne Excimer Laser and Research Group.
OBJECTIVE: The excimer laser allows the controlled ablation of corneal tissue to correct refractive error. We assessed the efficacy of excimer laser treatment for persons with high (spherical equivalent between -5 and -10 diopters) and extreme (spherical equivalent greater than -10D) myopia. METHODS: Patients were assessed 1, 3, and 6 months postoperatively. A VisX Twenty/Twenty laser was used. Visual acuity, refraction, corneal clarity, and adverse reactions were evaluated at each visit. RESULTS: Six month follow-up data were available for 194 high myopes and 53 extreme myopes. Postoperative healing was similar for the two groups. Six months postoperatively, 89.2% of high myopes and 49% of extreme myopes were within 2D of planned refraction. At 6 months, 28% of high myopes had an uncorrected visual acuity of 20/20 and 71% had an uncorrected visual acuity of 20/40. Of extreme myopes, 4% had an uncorrected visual acuity of 20/20 and 30% had an uncorrected visual acuity of 20/40. Significantly more corneal haze was observed in the extreme myopes. Loss of 2 or more lines of best corrected visual acuity was observed in 13% of high myopes and 13% of extreme myopes at 6 months. CONCLUSIONS: Excimer laser photorefractive keratectomy is an alternative means of treating high and extreme myopia and can cause a significant reduction in myopia. There is a need to gather further information as more patients are followed up for greater time.
Adult↗