摘要:

An automated portable keratometer was used to measure corneal curvatures of cadaveric donor corneas. Globe contours were maintained despite unrecordable intraocular pressures, and reproducible keratometric values were consistently obtainable. Evaluation of nondonor eyes, at varying intraocular pressures (IOPs) ranging from 0 to 66 mm Hg (Schiotz), yielded keratometric readings that were not significantly different at different IOPs. Early correlation of keratometric values in five grafted eyes showed a trend of ±0.5 D from measured cadaveric donor keratometry values when compared with that of the donor sutured into the recipient bed. The study suggests the feasibility of incorporating cadaveric donor keratometry readings in the prediction of final donor keratometric values in the recipient bed, thus allowing more accurate selection of intraocular lens powers for triple procedures and the avoidance of transplanting corneas with unusual or abnormal corneal curvatures.

ISSN:0277-3740    

出版商:OVID    

年代:1994

数据来源: OVID

摘要:

In a previous study, we reported that a single intravenous pulse of 500 mg of methylprednisolone is more effective than oral prednisone in reversing rejection in patients who present early with severe endothelial rejection. In addition, the grafts that survived were less likely to undergo a further rejection episode. This study investigates whether a second pulse given at 24 h (n=31) or at 48 h (n=29) has any advantage over a single pulse (n=30). All three treatment regimens were equally effective in reversing rejection (74.2%, 79.3%, and 83.3%, respectively), and there was no statistical difference in graft survival. An additional pulse therefore appears to offer no advantage over single pulse therapy. In high-risk grafts, current therapy has been reported to be less effective in reversing graft rejection. This study showed no significant difference between high- and low-risk grafts, indicating that pulse therapy may have a particular role in these difficult cases.

ISSN:0277-3740    

出版商:OVID    

年代:1994

数据来源: OVID

摘要:

Limbal allograft transplantation was performed consecutively in 16 eyes with thermal or chemical burns (n=5), Terrien's degeneration (n=2), congenital sclerocornea (n=1), Stevens-Johnson syndrome (n=1), and chronic keratoconjunctivitis (n=7), by transplanting randomly selected cadaver limbocorneal grafts to the recipient eye that had received superficial lamellar keratectomy to remove fibrovascular pannus. Oral cyclosporine A was administered immediately for 2.9 ± 1.3 months. During 18.5 ± 5.4 months of follow-up, the results showed improved visual acuity in 13 eyes (81.3%) and rapid (within 1 week) surface healing in 10 eyes (62.5%). Donor limbal tissue developed engorged and tortuous blood vessels in 12 eyes within 1-2 months, but these regressed within 3 months after surgery. No acute graft failure or allograft rejection could be identified. Twelve eyes (75%) showed total regression of vascularization and four eyes had decreased vascularization. These preliminary results indicate that limbal allograft transplantation may be able to reconstruct a corneal surface that has undergone bilateral diffuse destruction, including the loss of limbal epithelial stem cells.

ISSN:0277-3740    

出版商:OVID    

年代:1994

数据来源: OVID

摘要:

The traumatic loss of iris is often associated with symptoms of glare, which can be debilitating. This symptom may be benefitted by wearing a contact lens with a clear, central optical zone and opacification of the remainder. The patient who is contact lens-intolerant may be helped by tattooing of all of the cornea except the central visual axis. Four patients who had traumatic iris loss and who were treated by this technique reported reduced glare as well as improvement in the cosmetic appearance of the eye. Although corneal tattooing is an ancient procedure, it continues to be of benefit for selected patients.

ISSN:0277-3740    

出版商:OVID    

年代:1994

数据来源: OVID

摘要:

We studied both heat- and light-activated tissue glues, and while a heat-activated mixture such as albumin and fluorescein isothiocyanate was effective, we believed that a light-activated substance would have less of an effect on adjacent tissue. Our glue uses a photosensitive singlet oxygen generator to cross-link a protein solder with corneal stromal collagen. The mixture consists of 18% fibrinogen and 2.6 mg/ml of riboflavin-5-phosphate activated with a blue-green (488-514 nm) Argon laser. We tested our glue by soldering 5-mm penetrating central corneal incisions made in human cadaver eyes. The strength of the closure was measured by cannulating the vitreous cavity with an 18-gauge needle connected to a saline reservoir. The pressure in the reservoir was elevated by connecting it to a sphygmomanometer. Immediately following tissue closure, the intraocular pressure was increased until the wound burst. We soldered and measured 10 eyes and found a mean bursting pressure of 154 mm Hg, with a range of 80-260 mm Hg. Our laser-activated tissue glue is an effective adhesive for corneal tissue, and we now plan to carry out toxicity studies in living animals.

ISSN:0277-3740    

出版商:OVID    

年代:1994

数据来源: OVID

摘要:

We studied the recurrence rate of pterygium after administration of a single dosage of topical mitomycin C at the completion of pterygium surgery. Forty patients who had advanced or recurrent pterygium underwent excision of pterygium, leaving the sclera bare. Patients were randomized in a masked fashion into two groups of 20 patients each. Group 1 received a single dosage of topical 0.02% mitomycin C for 5 min at the completion of the surgery whereas group 2 underwent the same procedure but received NaCl 0.9% instead of mitomycin C. Patients were followed from 6 to 15 months in a masked manner. The pterygium recurred in one patient (5%) in group 1, whereas in group 2 the recurrence rate was 45% (p=0.0035). Formation of dellen and a delay of epithelialization for 5 weeks were found in one patient in group 2. No complications were observed in patients in group 1. This study indicates the possible advantage of administration of a single dosage of 0.02% mitomycin C for postoperative prevention of recurrence of pterygium.

ISSN:0277-3740    

出版商:OVID    

年代:1994

数据来源: OVID

摘要:

A double-blind, parallel, randomized study was conducted to compare the efficacy of Healon GV versus Healon in penetrating keratoplasty (PK). Its objective was to investigate whether Healon GV maintains space in the open anterior chamber better than Healon does during removal of the corneal button. Excluding those patients with an anterior chamber lens implant or a known history of glaucoma, 35 patients scheduled for PK entered the study. After penetration of the cornea with the trephine, a specific amount (0.2 ml) of Healon GV or Healon was injected into the anterior chamber. The corneal button was removed and the distance (mm) between iris and cornea (epithelial side) was measured with a digital slide gauge mounted between the permanent and mobile stand of the microscope. A significant difference between the two groups was shown in the measurements of the distance between the iris and the outer side of the cornea. The mean distance for Healon GV was 1.5 ± 0.6 mm and for Healon it was 1.1 ± 0.4 mm (p=0.038). The removal of the corneal button was significantly facilitated when Healon GV was used (p=0.021). In conclusion, Healon GV was found to be superior in the ability to maintain space in the open anterior chamber.

ISSN:0277-3740    

出版商:OVID    

年代:1994

数据来源: OVID

摘要:

Penetrating keratoplasty with intraocular lens (IOL) exchange is generally recommended for eyes with pseudophakic bullous keratopathy, especially when the keratopathy is associated with uveitis, chronic cystoid macular edema, or a uveitis-glaucoma-hyphema syndrome. Review of the literature has shown basically equivalent long-term results of penetrating keratoplasty and IOL exchange using both Kelman-style, flexible, open-loop anterior chamber lenses and acapsular fixation of sutured posterior chamber lenses. The use of suturefixated posterior chamber IOLs appears warranted in centers where the surgeon has extensive experience with this specific technique and in cases with special indications, for example, in eyes with extensive angle abnormalities. However, because this technique is more difficult to perform, and in the absence of such preexisting contraindications, for most practices we do not hesitate to recommend the use of a Kelman-style anterior chamber lens during routine cases of penetrating keratoplasty and IOL exchange.

ISSN:0277-3740    

出版商:OVID    

年代:1994

数据来源: OVID

摘要:

Silicone rubber contact lenses (SRCLs) are infrequently used because of the risk of developing unpredictable lens tightening, their poor availability, and their expense. However, their high oxygen transmissibility and nonabsorption of water make them valuable as therapeutic lenses. SRCLs are routinely used in our management of severely dry eyes, decompensated or vascularised corneas, and conditions where the corneal shape is flat or irregular. The records of 48 consecutive patients fitted with SRCLs between January 1989 and June 1990 were studied. The clinical history, indications, complications, success, and duration of SRCL wear were analysed. Therapeutic goals, which included epithelial healing, sealing of corneal perforations, and improved comfort and vision, were achieved in 53 of 62 eyes. The best corrected acuity was attained using SRCLs in 58 of 62 eyes. Failure of lens wear was due to lens tightening (four eyes), spoilation (two), discomfort, fornix shortening, handling problems, and decentration (one each). Infective keratitis complicated one case, but SRCL wear was resumed after successful treatment. With adequate follow-up, SRCLs have a low complication rate and are well tolerated even in severely compromised eyes, for which conventional lenses may be contraindicated. Their continued use as therapeutic lenses is advocated in carefully selected cases.

ISSN:0277-3740    

出版商:OVID    

年代:1994

数据来源: OVID

摘要:

Effects of and recovery from continuous wear of four rigid gas permeable (RGP) contact lenses was assessed by noninvasive measurement of lactate dehydrogenase (LDH) activity and isozyme pattern in rabbit tears. Oxygen transmissibility (Dk/L) of lenses used was 27, 44, 84, and 97 x 10-9(cm/s)(ml O2/ml mm Hg); lens thickness (0.15 mm) and diameter (14.0 mm) were standardized. Lenses were worn continuously for 90 days; recovery was assessed 30 days after cessation of lens wear. LDH activity was measured by UV rate assay; isozyme subtypes were determined by agarose gel electrophoresis. Light and scanning electron microscopy (LM, SEM) were used with the determination of total protein as additional measures of lens effects. LDH levels were inversely correlated with lens Dk/L values; low Dk/L values increased the anaerobic (LDH4, 5)/aerobic (LDH1,2,3) subtype,, ratio indicating in vivo metabolic shift. SEM observations were consistent with these results. There was no significant difference in the total cell content of tears or total tear protein levels between control and RGP test-wear groups. Measurement of tear LDH activity and isozyme ratios appears to provide a sensitive, noninvasive assessment of the effects of RGP lens-induced hypoxia over time on the corneal surface. A level of Dk/L of ≥84appears best for maintaining corneal physiology during extended wear. Recovery from chronic lens-induced hypoxia is characterized by a return to normal tear LDH levels and isozyme subtypes.

ISSN:0277-3740    

出版商:OVID    

年代:1994

数据来源: OVID