摘要:

Corneal neovascularization complicates many anterior segment diseases. Corneal laser photocoagulation using yellow light (577 nm) has been shown to reduce corneal neovascularization. No histopathologic studies of the effects of this treatment on the eye have been reported, however. Target (cornea) and nontarget (iris, lens, retina, and choroid) ocular tissue were studied 1, 24, and 48 h and 5 days after yellow dye corneal laser photocoagulation in a rabbit model of corneal neovascularization. Biomicroscopic examination of the corneas revealed intracorneal hemorrhage in five of 24 (21%) eyes of nonpigmented rabbits. Faint lenticular opacities were observed in two eyes of pigmented rabbits 24 h after laser treatment. Histopathologic examination revealed increased cellularity (neutrophils) (p < 0.005) in the cornea, increasing from 1 h after treatment, peaking 24 h later, and persisting past 5 days. Distortion of the corneal lamellae by red blood cells occurred in eyes in which intracorneal hemorrhage developed. These results indicate that corneal laser photocoagulation using yellow light is a relatively safe procedure for reducing corneal neovascularization.

ISSN:0277-3740    

出版商:OVID    

年代:1993

数据来源: OVID

摘要:

The effect of ascorbate and L-ascorbic acid 2-phosphate (P-Asc), a stable derivative of ascorbate, on the growth of cultured rabbit keratocytes was examined. In a 12-day culture, P-Asc (0.05-0.1 mM) and ascorbate (0.05 mM) enhanced the growth of the cells, whereas 0.1-1.0 mM ascorbate was cytotoxic to the cells. An increase in the concentration of P-Asc up to 1.0 mM resulted in no further change in the cell growth. The effect of 0.1 mM P-Asc was observed after the confluency had been achieved in the culture. The lower toxicity of P-Asc may be due to its stability. The presence of both 0.1 mM P-Asc and mouse epidermal growth factor in the medium stimulated cell growth to a higher degree than each factor alone. The results suggested that these two factors enhance the growth of keratocytes in a different manner.

ISSN:0277-3740    

出版商:OVID    

年代:1993

数据来源: OVID

摘要:

Measurements of electrical potential difference across isolated rabbit corneal endothelium (transendothelial electrical potential difference, TEPD) were used to evaluate the effect of two commonly used commercially prepared intraocular irrigation balanced salt solutions, BSS and BSS +, together with our own standard bicarbonatecontaining control solution (BS). The highest and most durable TEPD values were obtained by using BSS +; TEPD began at 550 μ V, peaked at 600 μ V 1 h later, and then decreased slowly down to some 300 μ V after about 8 h. Gassing BSS+ with an air/5% CO2mixture was optimal; gassing it with air reduced the TEPD values slightly, by about 10%. On the other hand, perfusion with BSS gassed with air had a rapid and marked adverse effect; the TEPD, which began at some 500 μ,V, fell down precipitously to about 50 μ V after 1 hour. In contrast, perfusion with BSS on the endothelial side with the addition of BS to the stromal side, both sides being gassed with an air/5% CO2mixture, maintained the TEPD at levels near those obtained with BSS +. We attribute the adverse effect by BSS to the absence of bicarbonate in it. From these and past results, we conclude that BSS cannot be recommended for intraocular use as a properly balanced saline solution.

ISSN:0277-3740    

出版商:OVID    

年代:1993

数据来源: OVID

摘要:

FK-506 is a new immunosuppressant with the ability to inhibit activation of T-lymphocytes that would be cytolytic to an allograft. We studied periocular injection of FK-506 in a rat penetrating keratoplasty model. Corneas were transplanted from Brown Norway rats into Lewis rat recipients. The transplanted rats received periocular injection of either 0.5 mg/kg FK-506 or an equivalent volume of FK-506 vehicle only. Injections were given 1 day before, at keratoplasty, and every other day after keratoplasty until allograft rejection. The group receiving FK- 506 had a significant delay in allograft rejection (p < 0.05). The FK-506 group rejected 12-20 days postkeratoplasty with a mean rejection time (MRT) of 14.3 days, compared with 8-14 days (MRT 11.1 days) for the control group. We conclude that periocular administration of FK- 506 is effective in prolonging allograft survival in the rat penetrating keratoplasty model.

ISSN:0277-3740    

出版商:OVID    

年代:1993

数据来源: OVID

摘要:

The influence of epidermal growth factor (EGF), basic fibroblast growth factor (bFGF), and insulin-like growth factor (IGF) I and II on wound healing was investigated in a corneal endothelial system with minimal mitotic activity, using serum-deprived kitten corneal endothelial-cell cultures. After wounding, growth factors were added and wound diameter was evaluated. The DNA synthesis was determined by 3H-thymidine labeling. Wounds did not close in the control cultures grown in serum-free medium without growth factors. The IGF I or II, alone (10 and 100 ng/ml) or added (10 ng/ml) to EGF or bFGF, had no significant effect on wound closure or thymidine uptake. With EGF or bFGF (10 ng/ml), wounds closed after 15 days. Wounds closed after 10 days with EGF or bFGF (100 ng/ml) alone or with the combination of EGF and bFGF (each at 10 ng/ml). Combined EGF and bFGF (each at 100 ng/ml) did not enhance wound closure further. Thymidine uptake was significantly higher in cultures treated with EGF or bFGF (10 ng/ml) than in controls. The uptake could be increased, if both growth factors were combined, but only to the same level achieved with a single factor at 100 ng/ml. This study showed that EGF and bFGF, but not IGF I or II, enhanced wound closure and DNA synthesis in a corneal endothelial cell system that had minimal mitotic activity.

ISSN:0277-3740    

出版商:OVID    

年代:1993

数据来源: OVID

摘要:

Epidemics of viral conjunctivitis are a major public health problem in the Far East. No treatment has been shown to shorten the duration of illness. We studied the clinical course of epidemic keratoconjunctivitis in 74 patients during an outbreak of nearly 3,000 cases in late 1988 at a U.S. military base in the Philippines. Patients were randomly assigned to treatment with trifluridine, dexamethasone, or artificial tears, and examined in a doublemasked fashion. There was no significant difference between the results of the three treatments. No bacterial cultures were positive. The prompt use of patient isolation, identification of nonadenoviral red eyes, and symptomatic treatment without steroids, antiviral, or antibiotic medication is recommended in cases of epidemic keratoconjunctivitis. This is the largest series of cases of epidemic keratoconjunctivitis with laboratory confirmation reported from the Philippines.

ISSN:0277-3740    

出版商:OVID    

年代:1993

数据来源: OVID

摘要:

Gentamicin is the only antibiotic currently added to commercially available corneal storage media. To reduce the potential for bacterial dissemination from donor corneal tissue to the recipient eye, we evaluated the addition of vancomycin to corneal storage media. When added to Dexsol at a concentration of 200 μ,g/ml, vancomycin levels were maintained, showing at 7 % decrease in vancomycin concentration per month, measured== 90 days after its addition. Human corneas were stored in gentamicin-free Dexsol (Chiron Ophthalmics, Inc., Irvine, CA, U.S.A.) containing 150 μ g/ml vancomycin. Corneal tissue levels of vancomycin determined by agar diffusion bioassay were 201, 226, 292 μ g/ml at 1, 3, and 7 days of storage respectively, suggesting that corneal tissue concentrates vancomycin with time. No differences in endothelial cell count or cell death were seen in corneas stored in Dexsol (containing gentamicin) or Dexsol plus vancomycin when followed for *sl4 days. Vancomycin added to corneal storage media should reduce the potential for endophthalmitis due to gentamicin-resistant organisms.

ISSN:0277-3740    

出版商:OVID    

年代:1993

数据来源: OVID

摘要:

Corneal asphericity was measured before and after surgery in 81 radial keratotomy eyes. Asphericity was calculated between keratoscope rings 2 and 9, representing corneal diameters of 2.3 mm and 7.6 mm. Statistical methods were used to assess the relationship between postoperative asphericity and undilated, uncorrected visual acuity. Smaller radial keratotomy clear zones resulted in greater negative asphericity after surgery (R= 0.74, p <0.0001). For eyes with smaller clear zones of <4.0 mm, postoperative negative asphericity was high (mean —6.44). Eyes in this smaller clear zone range had better uncorrected visual acuity if they possessed higher levels of negative asphericity (Mann-Whitney U test, p <0.0001). The study suggests that eyes with smaller clear zones gain a beneficial increase in depth of field as the degree of negative asphericity increases. The study offers this as one reason that radial keratotomy patients with residual refractive error often have better uncorrected visual acuity than expected.

ISSN:0277-3740    

出版商:OVID    

年代:1993

数据来源: OVID

摘要:

Bupivacaine is a local ocular anesthetic with a long duration of action when administered by retrobulbar injection. To determine the potential for the use of bupivacaine as a topical ocular anesthetic, the onset and duration of action and toxicity of various concentrations of bupivacaine were studied after instillation in rabbit eyes. The onset and duration of action were not significantly different from that of topical 0.5% proparacaine. Increasing the pH of the bupivacaine solution from 5.7 to 6.5 nearly doubled the duration of action, but the increase was not sufficient to be clinically important. Slit lamp biomicroscopic examination and scanning electron microscopy showed that bupivacaine was less toxic to the corneal epithelium than 0.5% proparacaine. Healing after keratectomy was significantly more rapid in eyes treated with 0.75% bupivacaine, compared with eyes treated with 0.5% proparacaine. These results suggest that bupivacaine may be less toxic to the corneal epithelium than proparacaine and could be clinically useful for topical ocular anesthesia, particularly if pharmacologic modifications can increase the duration of anesthesia provided by this drug.

ISSN:0277-3740    

出版商:OVID    

年代:1993

数据来源: OVID

摘要:

Adult male C57BL/6J inbred mice were subjected to ultraviolet radiation (UVR) exposure (302-nm peak wavelength; average intensity 282 (µ W/cm2) for 1 h and monitored for ocular aldehyde dehydrogenase (ALDH) and alcohol dehydrogenase (ADH) activity changes over a period of 25 days. Dramatic reductions in activities were observed by 4-6 days postexposure, resulting in enzyme levels of 15-16% of control animals. Major decreases in corneal enzyme levels were predominantly responsible for these changes. Ocular morphology was observed throughout using a photoslit-lamp biomicroscope, with maximum corneal clouding occurring at days 4-6. These data support earlier proposals for major roles for these corneal enzymes in assisting the cornea in protecting the eye against UVR-induced tissue damage.

ISSN:0277-3740    

出版商:OVID    

年代:1993

数据来源: OVID