Your browser doesn't support javascript.
loading
Show: 20 | 50 | 100
Results 1 - 20 de 32
Filter
2.
Ophthalmology ; 106(10): 1966-74; discussion 1974-5, 1999 Oct.
Article in English | MEDLINE | ID: mdl-10519594

ABSTRACT

PURPOSE: To determine the safety and effectiveness of laser in situ keratomileusis (LASIK) for visual rehabilitation of residual myopia and astigmatism after penetrating keratoplasty. DESIGN: Prospective, noncomparative case series. PARTICIPANTS: LASIK was performed on 23 eyes of 22 patients unable to wear glasses or contact lenses after penetrating keratoplasty due to anisometropia, high astigmatism, and/or contact lens-intolerance. METHODS: All patients underwent LASIK for visual rehabilitation after penetrating keratoplasty. Uncorrected visual acuity and best spectacle-corrected visual acuity, degree of anisometropia, and corneal transplant integrity were recorded before surgery, as well as at 1 month, 3 months, 6 months, and 12 months after LASIK surgery. RESULTS: The mean spherical equivalent before surgery was -7.58+/-4.42 diopters (D), which was reduced to -1.09+/-2.01 D, -0.79+/-1.84 D, -0.77+/-1.25 D, and -1.57+/-1.20 D, respectively, at 1, 3, 6, and 12 months after LASIK. The mean cylinder before surgery was 3.64+/-1.72 D, which was reduced to 1.98+/-1.15 D, 1.64+/-1.14 D, 1.48+/-0.92 D, and 1.29+/-1.04 D, respectively, at 1, 3, 6, and 12 months after LASIK. Spherical equivalent anisometropia was reduced from a mean of 6.88+/-4.4 D to 1.42+/-1.05 D at the final examination. Best-corrected visual acuity remained the same or improved in 21 of 23 eyes and decreased by 1 and 3 lines in 2 patients. There were no surgical flap or corneal transplant complications. CONCLUSIONS: LASIK is a viable treatment alternative for myopia and astigmatism after penetrating keratoplasty in patients who are contact lens-intolerant. LASIK is more effective in treating myopia than astigmatism after penetrating keratoplasty.


Subject(s)
Astigmatism/surgery , Cornea/surgery , Keratoplasty, Penetrating/adverse effects , Laser Therapy , Myopia/surgery , Adult , Aged , Aged, 80 and over , Astigmatism/etiology , Cell Count , Corneal Topography , Corneal Transplantation/methods , Endothelium, Corneal/cytology , Female , Humans , Male , Middle Aged , Myopia/etiology , Prospective Studies , Refraction, Ocular , Surgical Flaps , Visual Acuity
3.
J Cataract Refract Surg ; 24(11): 1434-40, 1998 Nov.
Article in English | MEDLINE | ID: mdl-9818331

ABSTRACT

PURPOSE: To evaluate the use of a picosecond neodymium:YLF (Nd:YLF) laser as a nonmechanical intrastromal microkeratome. SETTING: Universita Cattolica del Sacro Cuore, Rome, Italy. METHODS: An intrastromal spiral disc pattern of picosecond laser pulses was used to create a corneal flap for laser in situ keratomileusis (LASIK) in 14 partially sighted eyes. RESULTS: Flaps with a 6.0 mm diameter and 180 to 200 microns depth were successfully created in most cases. The underlying stroma was treated with a Lambda Physik excimer laser using a 3.5 to 4.5 mm optical zone. Patients were divided into 3 groups for target corrections of 5.0, 10.0, and 15.0 diopters of myopia. Good corneal clarity and refractive undercorrection were recorded in each group 6 months postoperatively. The undercorrection was due in part to the limited optical zone of the laser's delivery system. Some flap decentration was noted. CONCLUSION: This pilot study indicates that the Nd:YLF picosecond laser may be clinically applied for creating corneal flaps for LASIK. Further refinements of the laser delivery system will include enlargement of the flap diameter and improvements in flap centration. The use of a femtosecond laser may expand the capabilities and precision of this technology.


Subject(s)
Blindness/surgery , Corneal Stroma/surgery , Laser Therapy/methods , Myopia/surgery , Ophthalmologic Surgical Procedures , Adult , Aged , Corneal Topography , Female , Humans , Laser Therapy/instrumentation , Male , Middle Aged , Pilot Projects , Surgical Flaps , Treatment Outcome , Visual Acuity
4.
Am J Ophthalmol ; 121(6): 718-20, 1996 Jun.
Article in English | MEDLINE | ID: mdl-8644821

ABSTRACT

PURPOSE: To evaluate the ability of ultrasound biomicroscopy to monitor the repair of large Descemet's membrane detachments. METHODS: Intraoperative ultrasound biomicroscopy was performed in two patients who had undergone previous unsuccessful surgical repair of large Descemet's membrane detachments. RESULTS: Ultrasound biomicroscopy visualized and located Descemet's membrane detachment and verified proper suture placement and membrane repositioning. CONCLUSIONS: Ultrasound biomicroscopy is a useful tool to guide surgical repair of Descemet's membrane detachments, particularly when hazy media prevent satisfactory visualization.


Subject(s)
Cataract Extraction/adverse effects , Corneal Diseases/diagnostic imaging , Corneal Diseases/surgery , Descemet Membrane/diagnostic imaging , Descemet Membrane/surgery , Aged , Anterior Chamber/ultrastructure , Corneal Diseases/etiology , Corneal Edema/etiology , Female , Glaucoma/surgery , Humans , Microscopy , Monitoring, Intraoperative , Postoperative Complications , Suture Techniques , Trabeculectomy/adverse effects , Ultrasonography , Visual Acuity
5.
J Refract Surg ; 11(6): 442-7, 1995.
Article in English | MEDLINE | ID: mdl-8624827

ABSTRACT

BACKGROUND: We studied the histopathology of the stromal wound healing response in the cat cornea following intrastromal photorefractive keratectomy (IPRK) with the Nd:YLF picosecond laser. METHODS: Intrastromal PRK was performed in the anterior stroma of cat corneas with the Nd:YLF picosecond laser. The cats were sacrificed at predetermined intervals ranging from immediately to 6 months postoperatively. Effects of the laser treatment on the epithelium, Bowman's layer, stroma, and the endothelium were evaluated using light and scanning electron microscopy. No anti-inflammatory agents were used. RESULTS: Intrastromal PRK resulted in no perceptible damage to the corneal epithelium or Bowman's layer either acutely or at 6 months. The corneal stroma showed multiple cavitations immediately after intrastromal PRK, which collapsed over several hours, followed by thinning of the cornea over 2 weeks. At 1 month, the stromal collagen was abnormal with surrounding hypercellularity. The endothelium showed no injury, acutely or at 6 months. No thermal effects on stromal collagen were observed at 6 months, and disruption of the lamellar pattern was not apparent after the cavitation bubbles were reabsorbed. CONCLUSION: Intrastromal PRK can effectively remove stromal tissue without acute damage to the adjacent lamellae, epithelium, or endothelium. There is a transient cellular wound healing response associated with a transient stromal collagen abnormality at 2 weeks to 1 month, which was not apparent 2 months after the procedure.


Subject(s)
Corneal Stroma/surgery , Photorefractive Keratectomy , Wound Healing , Animals , Cats , Cornea/pathology , Corneal Stroma/physiopathology , Female , Lasers , Lasers, Excimer , Microscopy, Electron, Scanning , Photorefractive Keratectomy/instrumentation , Photorefractive Keratectomy/methods , Postoperative Period
6.
J Refract Surg ; 11(6): 448-52, 1995.
Article in English | MEDLINE | ID: mdl-8624828

ABSTRACT

PURPOSE: To evaluate corneal morphology in vivo following intrastromal photorefractive keratectomy (IPRK) with the Nd:YLF picosecond laser, using the ultrasound biomicroscope. MATERIALS AND METHODS: Myopic intrastromal PRK was performed in the anterior stroma of cat corneas with the neodymium:yttrium lithium fluoride (Nd:YLF) picosecond laser. Periodic examination of the treated corneas up to 6 months postoperative was performed with high resolution ultrasound biomicroscopy. Corneal thickness, depth of the laser patterns from the corneal surface, alignment of the laser treatment, extent of stromal opacification until resolution, and contour of the corneal surface were measured with the ultrasound biomicroscope throughout follow up. RESULTS: The treated corneas were thickened on ultrasonic biomicroscopy measurement immediately after intrastromal PRK and revealed a densely echogenic shadow parallel to the corneal surface at the treatment site. There was increased stromal echogenicity denoting mild edema. The echoes decreased over time and appeared thinner at 2 months compared to the preoperative and immediate postoperative measurements. At 6-month follow up, the treated corneas were echolucent on ultrasonic biomicroscopy. CONCLUSION: The ultrasound biomicroscope might become a helpful tool in assessing accuracy of treatment parameters of intrastromal PRK as well as in monitoring the response of the cornea to treatment.


Subject(s)
Cornea/diagnostic imaging , Corneal Stroma/surgery , Photorefractive Keratectomy , Animals , Cats , Female , Lasers , Lasers, Excimer , Photorefractive Keratectomy/instrumentation , Photorefractive Keratectomy/methods , Postoperative Period , Time Factors , Ultrasonography
7.
Ophthalmic Surg Lasers ; 26(5): 481-3, 1995.
Article in English | MEDLINE | ID: mdl-8963863

ABSTRACT

BACKGROUND AND OBJECTIVE: To determine the nature and chemical composition of the cavitation bubbles generated by intrastromal photorefractive keratectomy (IPRK) with the Neodymium: Yttrium Lithium Fluoride (Nd:YLF) picosecond laser. MATERIALS AND METHODS: IPRK was performed on the corneas of three fresh human cadaver eyes with the Nd:YLF picosecond laser. High energy levels of 200 mJ/pulse to 300 mJ/pulse were used to produce the maximum amount of gas within the corneal stroma. The cavitation bubbles produced in the stroma were aspirated using a gas-tight syringe connected to a valve, and the specimens were analyzed with a mass spectrometer. RESULTS: The experiment was performed on three different occasions using one cadaver eye in each experiment. The analysis consistently revealed a mixture of carbon dioxide, carbon monoxide, water vapor, oxygen, and nitrogen. Atmospheric control samples also revealed oxygen and nitrogen. No other components were detected. CONCLUSION: The gaseous by-products of IPRK with the picosecond laser result from the simple breakdown of stromal tissue and contain no toxic or unexpected components. We found that these gaseous products are capable of rapid elimination by absorption or diffusion out of the intact cornea.


Subject(s)
Corneal Stroma/chemistry , Gases/analysis , Mass Spectrometry , Photorefractive Keratectomy , Cadaver , Corneal Stroma/ultrastructure , Humans , Lasers, Excimer , Microscopy, Electron, Scanning , Postoperative Period
8.
Arch Ophthalmol ; 113(4): 499-505, 1995 Apr.
Article in English | MEDLINE | ID: mdl-7710402

ABSTRACT

OBJECTIVE: To evaluate the refractive effects of myopic intrastromal photorefractive keratectomy (IPRK) with the neodymium-yttrium lithium fluoride (Nd-YLF) picosecond laser. METHODS: A 1053-nm Nd-YLF picosecond laser was used to produce myopic IPRK in cat corneas at threshold energy densities. Preoperative corneal topography and ultrasonic pachymetry were performed followed by IPRK in one eye each of 21 cats. No anti-inflammatory medications were administered. Postoperative corneal topography, ultrasonic pachymetry, and slit-lamp examination were performed at scheduled intervals. RESULTS: An average topographic flattening of 11.4 diopters and pachymetric thinning of 50 microns at the center of the treatment zone were observed by 6 weeks following treatment. The average diameter of the zone of flattening was 5.1 mm at 6 weeks and 6.0 mm at 12 weeks postoperatively. At 6 months postoperatively, the average central corneal power was unchanged, while the average central thickness had returned to the preoperative value. A mild subepithelial haze was detected at 1 month following IPRK, which was barely perceptible at the second through sixth months. Regression of the topographic effects of PRK was not observed. CONCLUSION: Intrastromal PRK with the Nd-YLF picosecond laser produces central flattening of the cat cornea with barely perceptible stromal haze and no regression of topographic effect after 6 months in the absence of treatment with anti-inflammatory agents.


Subject(s)
Cornea/surgery , Corneal Stroma/surgery , Laser Therapy , Myopia/surgery , Animals , Cats , Cornea/pathology , Corneal Stroma/pathology , Female , Follow-Up Studies , Image Processing, Computer-Assisted , Myopia/pathology
10.
Ophthalmic Surg ; 25(5): 284-7, 1994 May.
Article in English | MEDLINE | ID: mdl-8058258

ABSTRACT

Preoperative evaluation and surgical planning for penetrating keratoplasty in patients with dense corneal scars is often difficult because of poor visualization of the anterior segment. We performed ultrasound biomicroscopy (50-megahertz frequency, 50-micron resolution) on five eyes of five patients with dense corneal opacities of different etiologies to evaluate the anatomic relationships of the iris, lens, angle, and ciliary body. Corneal thickness, the presence or absence of iridocorneal adhesions, peripheral anterior synechiae, and cyclitic membranes, intraocular lens position, and relationships among intraocular structures could be evaluated in vivo. Ultrasound biomicroscopy is the optimal method of obtaining reliable, high-resolution images delineating anatomic relationships and pathology in the anterior segment. This information aids in surgical planning for penetrating keratoplasty and anterior segment reconstruction.


Subject(s)
Anterior Eye Segment/diagnostic imaging , Corneal Opacity/diagnostic imaging , Adult , Aged , Anterior Eye Segment/pathology , Corneal Opacity/etiology , Corneal Opacity/pathology , Humans , Infant, Newborn , Keratoplasty, Penetrating , Male , Microscopy , Middle Aged , Preoperative Care , Ultrasonography
12.
Arch Ophthalmol ; 111(2): 250-3, 1993 Feb.
Article in English | MEDLINE | ID: mdl-8431164

ABSTRACT

A recent case-control study indicated that the insertion of an intraocular lens with polypropylene (Prolene) haptic materials was a significant risk factor for postoperative endophthalmitis (odds ratio = 4.5, P < .01). In the present study, we used quantitative techniques to evaluate adherence of Staphylococcus epidermidis to two intraocular lens types--lenses with polypropylene haptic materials and all-polymethyl methacrylate optic and three-piece all-polymethyl methacrylate lenses--using a quantitative culture method, a radioisotope technique, and scanning electron microscopy. All three methods demonstrated approximately twice as many bacteria adherent to lenses with polypropylene haptic materials as to all-polymethyl methacrylate lenses. Scanning electron microscopy showed preferential bacterial adherence to the polypropylene haptic materials. These data provide a pathogenic mechanism to explain our epidemiologic findings of an increased risk of postoperative endophthalmitis associated with implantation of intraocular lenses with polypropylene haptic materials.


Subject(s)
Bacterial Adhesion , Equipment Contamination , Lenses, Intraocular/standards , Polypropylenes/standards , Staphylococcus epidermidis , Adsorption , Colony Count, Microbial , Endophthalmitis/epidemiology , Endophthalmitis/etiology , Endophthalmitis/microbiology , Isotope Labeling , Materials Testing , Methylmethacrylate , Methylmethacrylates/standards , Microscopy, Electron, Scanning , Postoperative Complications/epidemiology , Postoperative Complications/etiology , Postoperative Complications/microbiology , Risk Factors , Sonication , Staphylococcus epidermidis/growth & development , Staphylococcus epidermidis/isolation & purification
14.
Infect Dis Clin North Am ; 6(4): 777-87, 1992 Dec.
Article in English | MEDLINE | ID: mdl-1460262

ABSTRACT

Blepharitis is an acute or chronic inflammatory process involving the eyelids that is frequently associated with conjunctivitis. In its many clinical forms, blepharitis is one of the most common diseases seen by ophthalmologists; yet it remains a diagnostic and therapeutic challenge. This article reviews the clinical presentation, classification, diagnosis, etiology and pathogenesis, and treatment of blepharitis.


Subject(s)
Blepharitis/microbiology , Blepharitis/diagnosis , Blepharitis/parasitology , Chalazion/diagnosis , Diagnosis, Differential , Dry Eye Syndromes/diagnosis , Eye Infections, Bacterial/diagnosis , Eye Infections, Parasitic/diagnosis , Hordeolum/diagnosis , Humans , Staphylococcal Infections/diagnosis
15.
Ophthalmology ; 99(11): 1647-54, 1992 Nov.
Article in English | MEDLINE | ID: mdl-1454338

ABSTRACT

BACKGROUND: The use of topical mitomycin (mitomycin-C) as a medical adjunct to pterygium and glaucoma surgery is increasing. METHODS: The authors report on a series of 10 patients who experienced serious, vision-threatening complications associated with the use of this drug after pterygium surgery. RESULTS: Complications included severe secondary glaucoma (4 patients), corneal edema (3 patients), corneal perforation (1 patient), corectopia (2 patients), iritis (8 patients), sudden onset mature cataract (2 patients), scleral calcification (1 patient) and incapacitating photophobia and pain (8 patients). Two patients required penetrating keratoplasties and a third required three lamellar keratoplasties. Another patient underwent four additional surgeries including a conjunctival Z-plasty, scleral patch grafting, and conjunctival autografting before his intractable pain and photophobia resolved 15 months after the original surgery. Because of these complications, 6 patients required a total of 20 return visits to the operating room after their original pterygium surgery. In 5 eyes, visual acuity remained at 20/200 or less. Three of the six patients with the most severe complications had concomitant chronic external diseases (rosacea [3 patients], ichthyosis [1 patient], keratitis sicca [1 patient]). CONCLUSION: The authors urge extreme caution in the use of mitomycin. If mitomycin is used, the lowest possible concentration should be applied for the shortest time period in an effort to avoid these complications. A prospective multicenter study of the ophthalmic use of this medication is needed.


Subject(s)
Eye Diseases/chemically induced , Mitomycin/adverse effects , Pterygium/surgery , Adult , Aged , Calcinosis/chemically induced , Cataract/chemically induced , Contraindications , Corneal Diseases/chemically induced , Female , Humans , Iritis/chemically induced , Male , Middle Aged , Ophthalmic Solutions/adverse effects , Postoperative Complications , Pterygium/drug therapy , Scleral Diseases/chemically induced , Vision Disorders/chemically induced , Visual Acuity
17.
CLAO J ; 18(1): 59-63, 1992 Jan.
Article in English | MEDLINE | ID: mdl-1313747

ABSTRACT

Collagen shields applied to the corneas of patients with bacterial keratitis degrade rapidly, often within a few hours. Once treatment brings the infection under control, subsequently applied collagen shields degrade more slowly. In vitro models were established to evaluate the significance of these observations. Twenty-four and 72-hour collagen shields were incubated with collagenase from Clostridium histolyticum. The in vitro rate of digestion of the shields was directly proportional to the concentration of collagenase, with the rate of digestion of the 24-hour shields being greater than that of the 72-hour shields. Therefore, the rate of collagen shield degradation may be a clinically useful index of collagenase activity on the ocular surface. Ultrastructural studies of collagen shields from patients with acute bacterial keratitis revealed irregular degradation of shield matrix with no evidence of adherence of microorganisms or inflammatory cells. Co-incubation of deepithelialized rabbit corneas and collagen shields resulted in inhibition of the digestion of the rabbit corneas when the weight:weight ratio of collagen shield:rabbit cornea was increased to greater than or equal to 2:1. Collagen shields may inhibit corneal collagen degradation in infectious ulceration and melting disorders by effectively competing for collagenase on the ocular surface.


Subject(s)
Collagen/pharmacology , Cornea/enzymology , Microbial Collagenase/antagonists & inhibitors , Animals , Biological Dressings , Collagen/therapeutic use , Collagen/ultrastructure , Corneal Ulcer/microbiology , Corneal Ulcer/therapy , Humans , Microbial Collagenase/metabolism , Rabbits
18.
Ophthalmology ; 98(12): 1761-8, 1991 Dec.
Article in English | MEDLINE | ID: mdl-1775307

ABSTRACT

The authors conducted a case-control study to identify risk factors for postoperative endophthalmitis. Fifty-four cases of patients who developed endophthalmitis after intraocular surgery at the New York Eye and Ear Infirmary during the period from January 1988 through October 1990 were identified. A control group of 228 patients was randomly selected from the 24,105 patients who underwent intraocular surgery during this same period. Logistic regression analysis identified significant independent risks associated with intraoperative communication with the vitreous cavity (risk ratio 13.7, P less than 0.001) and use of an intraocular lens with haptics made of polypropylene (risk ratio 4.5, P = 0.007). The study predicts that there would be approximately 700 fewer cases of postoperative endophthalmitis annually in the United States (approximately a 50% decrease in incidence) if intraocular lenses with haptics made of polymethyl-methacrylate, rather than polypropylene, were used exclusively.


Subject(s)
Endophthalmitis/microbiology , Postoperative Complications/etiology , Adolescent , Adult , Aged , Aged, 80 and over , Case-Control Studies , Cataract Extraction , Child , Cross Infection/epidemiology , Endophthalmitis/epidemiology , Eye Infections, Bacterial/epidemiology , Female , Humans , Lenses, Intraocular , Male , Methylmethacrylates , Middle Aged , New York/epidemiology , Odds Ratio , Polypropylenes , Postoperative Complications/epidemiology , Random Allocation , Regression Analysis , Risk Factors
19.
Ophthalmology ; 98(12): 1769-75, 1991 Dec.
Article in English | MEDLINE | ID: mdl-1775308

ABSTRACT

The authors conducted an open-label nonrandomized parallel trial to examine whether the preoperative application of povidone-iodine to the ocular surface reduces the incidence of endophthalmitis after intraocular surgery. During an 11-month period, topical 5% povidone-iodine was used to prepare the conjunctiva in 1 set of 5 operating rooms, while silver protein solution was used in another set of 5 rooms. In all cases, surgeons continued to use their customary prophylactic antibiotics. A significantly lower incidence of culture-positive endophthalmitis (P less than 0.03) was observed in the operating rooms using povidone-iodine (2 of 3489 or 0.06%) compared with those using silver protein solution (11 of 4594 or 0.24%). Use of topical povidone-iodine in over 3000 cases was not associated with any adverse reactions. In a majority of the observed cases of endophthalmitis, some form of intraoperative communication with the vitreous cavity existed.


Subject(s)
Endophthalmitis/prevention & control , Eye Infections, Bacterial/prevention & control , Povidone-Iodine/administration & dosage , Silver Proteins/administration & dosage , Administration, Topical , Adult , Aged , Aged, 80 and over , Anti-Bacterial Agents/therapeutic use , Bacteria/isolation & purification , Conjunctiva/drug effects , Endophthalmitis/epidemiology , Endophthalmitis/microbiology , Eye Infections, Bacterial/epidemiology , Female , Humans , Incidence , Male , Middle Aged , New York/epidemiology , Operating Rooms , Postoperative Complications/prevention & control , Prospective Studies
20.
Arch Ophthalmol ; 109(12): 1703-6, 1991 Dec.
Article in English | MEDLINE | ID: mdl-1841580

ABSTRACT

The effects of gas-permeable contact lens wear on the density and morphologic characteristics of corneal endothelial cells were prospectively studied by wide-field specular microscopy in 18 eyes that had undergone keratoplasty at least 14 months previously. Daily-wear rigid gas-permeable lenses were fitted to allow as much movement and tear exchange as possible. There was no evidence of morphologic instability of the endothelial cells during the course of the study, with a mean duration of lens wear of 9.8 months. Although there is concern over adverse effects associated with polymethylmethacrylate contact lens wear, this study suggests that the endothelium of a corneal transplant tolerates rigid gas-permeable lens wear without adverse effect during a limited period of follow-up.


Subject(s)
Contact Lenses/adverse effects , Corneal Transplantation/pathology , Endothelium, Corneal/pathology , Follow-Up Studies , Humans , Least-Squares Analysis , Prospective Studies
SELECTION OF CITATIONS
SEARCH DETAIL
...