Quantification of the ultraviolet radiation (UVR) field in the human eye in vivo using novel instrumentation and the potential benefits of UVR blocking hydrogel contact lens.

BACKGROUND/AIMS: Certain degenerative eye conditions occur predominantly nasally, at the limbal region, and are associated with solar ultraviolet radiation (UVR) induced damage. The relative contribution to the in vivo ocular flux of (a) the reflection of UVR incident on the skin of the nose onto the nasal limbus, and (b) the focusing of UVR incident on the temporal side of the cornea onto the nasal limbus were examined. METHODS: A novel photodiode sensor array was used to measure the UVR field across the eye. In addition, a novel spectrometer set-up was used to measure the spectrum of radiation refracted across the cornea. The efficacy of UVR blocking hydrogel contact lenses in filtering incident UVR was assessed in vivo. RESULTS: Qualitative and quantitative data indicated an increase nasally of UVR. Photodiode readings showed a net UVR increase from the temporal to the nasal side. Transmission curves showed that most UVR incident on the limbal region is either absorbed by, or transmitted through, the ocular tissues. This radiation is filtered by UVR blocking soft contact lens. CONCLUSIONS: An increased UVR flux on the nasal side of the eye, due to reflection off the nasal skin, was identified in vivo. Any UVR passing through the cornea is either absorbed by the conjunctiva and/or transmitted through it onto the sclera where it is absorbed. UVR blocking hydrogel contact lenses can eliminate these sources of UVR.

Immune-mediated corneal melting disease.

Corneal melting disease is, as illustrated, a very severe problem for patients. Correct diagnosis and aggressive management is critical. Help from general physicians and rheumatologists as required is essential, given that the medications used have significant toxic effects.

Localization of the gene for autosomal recessive congenital hereditary endothelial dystrophy (CHED2) to chromosome 20 by homozygosity mapping.

Congenital hereditary endothelial dystrophy (CHED) is a corneal disorder that presents with diffuse bilateral corneal clouding. Vision may be severely impaired, and many patients require corneal transplantation. Both autosomal dominant (AD) and autosomal recessive (AR) forms of the disorder have been described. The gene responsible for AD CHED (HGMW-approved symbol CHED1) has been mapped to the pericentromeric region of chromosome 20. Investigating a large, consanguineous Irish pedigree with autosomal recessive CHED, we have previously excluded linkage to this AD CHED locus. We now describe a genome-wide search using homozygosity mapping and DNA pooling. Evidence of linkage to chromosome 20p was demonstrated with a maximum lod score of 9.30 at a recombination fraction of 0.0 using microsatellite marker D20S482. A region of homozygosity in all affected individuals was identified, narrowing the disease gene locus to an 8-cM region flanked by markers D20S113 and D20S882. This AR CHED (HGMW-approved symbol CHED2) disease gene locus is physically and genetically distinct from the AD CHED locus.

Vernal keratoconjunctivitis.

Vernal keratoconjunctivitis therefore, if managed properly, can be controlled. Inaccurate diagnosis or staging of the disease, together with inaccurate treatment will however, result in changes which can jeopardize sight and may even necessitate corneal surgery at a later date.

Homozygosity mapping and linkage analysis demonstrate that autosomal recessive congenital hereditary endothelial dystrophy (CHED) and autosomal dominant CHED are genetically distinct.

BACKGROUND: Congenital hereditary endothelial dystrophy (CHED) is a corneal dystrophy characterised by diffuse bilateral corneal clouding resulting in impaired vision. It is inherited in either an autosomal dominant (AD) or autosomal recessive (AR) manner. The AD form of CHED has been mapped to the pericentromeric region of chromosome 20. Another endothelial dystrophy, posterior polymorphous dystrophy (PPM), has been linked to a larger but overlapping region on chromosome 20. A large, Irish, consanguineous family with AR CHED was investigated to determine if there was linkage to this region. METHODS: The technique of linkage analysis with polymorphic microsatellite markers amplified by polymerase chain reaction (PCR) was used. In addition, a DNA pooling approach to homozygosity mapping was employed to demonstrate the efficiency of this method. RESULTS: Conventional genetic analysis in addition to a pooled DNA strategy excludes linkage of AR CHED to the AD CHED and larger PPMD loci. CONCLUSION: This demonstrates that AR CHED is genetically distinct from AD CHED and PPMD.

Association of HLA type with pseudoexfoliation of the lens capsule.

AIMS/BACKGROUND: To identify an HLA association with pseudoexfoliation of the lens capsule to support the hypothesis that there is a genetic predisposition to pseudoexfoliation. A randomised trial would be ideal for establishing a relation but is more costly and time consuming to conduct. Case-control studies provide an alternative method of establishing a relation. METHODS: The study group comprised 128 subjects who presented to a major eye centre with pseudoexfoliation. Data from blood donors representative of the population of Ireland were used to form a control group. RESULTS: An HLA association with pseudoexfoliation is identified for 14 antigens. Eleven antigens (HLA A1, A33, B8, B47, B51, B53, B57, B62, DR3, DR12, and DR13) are significantly more common in the pseudoexfoliation group while three antigens (HLA B12, B17, and DR2) are significantly less common. Four HLA antigens are strongly associated, with odds ratios of over 7.5. CONCLUSION: The strength of this HLA association is supportive evidence for a genetic component to the development of pseudoexfoliation of the lens capsule.

Randomised trial of ganciclovir and acyclovir in the treatment of herpes simplex dendritic keratitis: a multicentre study.

AIMS: This study was designed to assess the relative efficacy of topical ganciclovir 0.15% gel and acyclovir 3% ointment in the treatment of herpes simplex dendritic keratitis. METHODS: Both treatment modalities were administered on a five times daily basis to patients suffering from herpes simplex keratitis. Patients were assigned randomly to one of the two treatment groups for the purpose of the trial. They were then examined on days 2, 7, 10, and 14 to assess the rate of healing of the dendritic ulceration. RESULTS: There was no statistically significant difference detected in the rate of healing between the two treatment groups over the course of the trial. CONCLUSIONS: Review of the relative efficacy of topical ganciclovir and acyclovir in the treatment of herpes simplex dendritic keratitis showed that both treatment modalities were equally effective in their ability to heal the viral induced corneal ulceration. There were no significant side effects or adverse effects reported for either treatment modality.

Adherence of human lens epithelial cells to conventional poly(methyl methacrylate), heparin-surface-modified, and polyHema lenses.

We developed an in vitro model to assess the adherence of human lens epithelial cells to three types of intraocular lenses: poly(methyl methacrylate) (PMMA), heparin-surface-modified PMMA (HSM-PMMA), and polyHema. Lenses were incubated with a fixed number of human lens epithelial cells. Adherent cells were counted after 72 hours in culture. Scanning electron microscopy showed significantly fewer cells adhering to the HSM-PMMA and polyHema lenses than to the PMMA lenses (P < .01). Repeat experiments on cell lines established from different donors confirmed these findings.

Daunomycin as an inhibitor of human lens epithelial cell proliferation in culture.

Posterior capsule opacification is still a major complication of both extracapsular cataract extraction and phacoemulsification. We evaluated the effects of the anti-proliferative agent daunomycin on cultured human and bovine lens epithelial cell viability and proliferation. After ten minutes of exposure, low concentrations of the agent markedly inhibited the proliferation of both cell types. The calculated LD50 for the drug against human cells was 2.20 micrograms/ml and against the bovine cells was 0.38 microgram/ml. The bovine cells appeared to be slightly more susceptible to the drug's effects, although this difference was not marked. Our results indicate that daunomycin is a potent inhibitor of both human and bovine lens epithelial cells in the laboratory.

Topical ciprofloxacin in the treatment of blepharitis and blepharoconjunctivitis.

An international multicentre study assessed the clinical and antibacterial efficacy of a new topical ophthalmic formulation of the quinolone antimicrobial agent ciprofloxacin and compared it with that of tobramycin ophthalmic solution in patients with blepharitis and blepharoconjunctivitis. The study consisted of a randomised double-masked between-group evaluation of 464 patients, 230 of whom were treated with ciprofloxacin and 234 with tobramycin. There was qualitative and quantitative bacteriology, and clinical assessment of ocular symptoms and signs before and after a seven-day course of treatment. Bacteriological cultures demonstrated eradication or reduction of potentially pathogenic bacteria in 93.7% of eyes (ciprofloxacin) versus 88.9% of eyes (tobramycin), seven days after starting treatment. Clinically more than 80% of patients in both treatment groups were cured or improved after seven days. No statistically significant differences were observed between the two treatment groups. No serious side-effects were observed after use of either antimicrobial agent. Ciprofloxacin ophthalmic solution appears safe and effective. The spectrum of activity and clinical efficacy of this new formulation are discussed in comparison with currently used antimicrobial agents.

Effect of topical cyclosporin A on conjunctival T cells in patients with secondary Sjögren's syndrome.

The effect of topical cyclosporin A on conjunctival T cells was studied in nine patients with secondary Sjögren's disease. Patients had conjunctival biopsies performed before and after a 6-week course of topical cyclosporin. Epithelium and substantia propria in the Sjögren's patients before treatment showed significantly more CD4+ cells than specimens taken from nine age- and sex-matched controls. Following treatment with topical cyclosporin, there was a significant reduction in the number of CD4+ cells in both the conjunctival epithelium and substantia propria. Despite the fact that the treatment resulted in immunopathological improvement, the clinical benefit was not as favorable. Our results suggest that topical cyclosporin may have a local immunosuppressive effect on the conjunctiva in patients with Sjögren's disease.

Evaluation of efficacy and safety of ciprofloxacin ophthalmic solution versus chloramphenicol.

The results of this clinical study demonstrate that ciprofloxacin ophthalmic solution 0.3% is as safe and as effective as 0.5% chloramphenicol ophthalmic solution in the treatment of conjunctivitis and blepharitis of bacterial aetiology. Both agents achieved microbiological improvement rates in excess of 90% after 1 week's treatment. On ciprofloxacin 93.5% of patients were judged clinically cured or improved versus 84.6% on chloramphenicol after 1 week. There were no serious adverse affects. One patient in each group suffered drug-related side-effects (chemosis, erythema) which resolved on discontinuation or changing of therapy. Cirpofloxacin is not associated with the rare, but serious, side effect of aplastic anaemia which is associated with chloramphenicol use. On the evidence of this study ciprofloxacin would appear to be an appropriate agent for general use as a topical ophthalmic formulation.

The management of ocular allergy.

There is a broad spectrum of ocular allergy. In the mild forms it is no more than an inconvenience, but severe forms such as eczematous kerato-conjunctivitis can be sight-threatening. However, with proper understanding of the diseases and constructive management, most patients can be satisfactorily controlled.

Acyclovir ointment plus topical betamethasone or placebo in first episode disciform keratitis.

Thirty patients with first episode disciform keratitis and with no previous steroid exposure were randomly assigned to double blind treatment with 3% acyclovir ointment and 0.1% betamethasone (Betnesol) drops or acyclovir ointment and matching placebo. In the steroid group 14 of the 15 patients healed in a mean time of 21.8 days. In the placebo group eight of the 13 patients healed in a mean time of 34.5 days. The difference in mean healing time between the two groups was significant (p < 0.05). The cumulative rate of healing was also quicker in the steroid group when compared with the placebo group (p < 0.001). Other clinical parameters improved more favourably in the combination treatment group. Four patients, two in either group, experienced a mild transient punctate epitheliopathy, but no other serious adverse effects were noted. There has been no significant difference in the recurrence rate between the two groups after a mean follow-up period of approximately 3 years.

Randomised double-masked trial of lodoxamide and sodium cromoglycate in allergic eye disease. A multicentre study.

135 patients were entered into a 28-day randomized double-masked multicentre study comparing the efficacy and short-term safety of lodoxamide 0.1% ophthalmic solution (Alomide--Alcon Laboratories), a mast cell stabilizer, with sodium cromoglycate 2% ophthalmic solution (Opticrom--Fisons Pharmaceuticals) in the treatment of allergic eye disease. Patients given lodoxamide 0.1% showed a significantly more rapid and greater improvement in their signs and symptoms of allergic eye disease than patients given sodium cromoglycate 2%. Both treatments were found to be safe, and side-effect profiles were comparable between the two treatment groups, although the overall incidence of side-effects in this study was found to be less frequent in the lodoxamide-treated group.

Electron microscopic appearances of human corneal endothelium following Nd:YAG laser iridotomy.

We looked at the electron microscopic appearances of the corneal endothelium following neodymium:YAG (Nd:YAG) laser iridotomy in a patient with a shallow anterior chamber. An area of denuded endothelial cells approximately 500 microns in diameter was produced when no contact lens was used. The area of cell loss was reduced by approximately 50% when an Abraham YAG goniolens was used. We conclude that the use of a positive plus contact lens can help minimize cell loss following Nd:YAG laser iridotomy.