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Biomedical subjects

R J Buckley

Publications and source records attributed to R J Buckley.

At least 37 records · Page 2Linked to original sources
PubMed1995

Medical applications of scleral contact lenses: 1. A retrospective analysis of 343 cases.

The medical indications for, and outcome of scleral contact lens wear in 517 eyes of 343 patients attending a Scleral Contact Lens Clinic during a 5-year period from July 1988 to June 1993 were analysed. Keratoconus was the most common condition requiring scleral lens wear (36.2%), followed by aphakia (18.4%), postpenetrating keratoplasty (12.0%), irregular astigmatism secondary to corneal disease (12.0%), high myopia (12.8%), and ocular surface disorders (6.4%). The main indication was visual (85.8%), whereas therapeutic indications accounted for 8.2% of cases. Seventy-six percent of cases had previously failed with other types of contact lenses. The majority of patients were initially fitted with impression moulded polymethylmethacrylate (PMMA) lenses (90.5%); other scleral lens types included preformed PMMA lenses, preformed high Dk gas-permeable (GP) lenses, and a GP/PMMA hybrid scleral lens design. Initial scleral lens fitting was successful in 93.2% of cases, and 71% remained successful with a mean duration of 11.8 years' follow-up. Complications included corneal vascularisation (13.3% of eyes), episodes of corneal oedema (7.4%), corneal abrasion (3.1%), and giant papillary conjunctivitis (1.7%). In addition to 19 eyes initially fitted with GP lenses, there were 99 eyes initially wearing PMMA lenses that were subsequently refitted with GP scleral lenses.

Adolescent↗
PubMed1995

Medical applications of scleral contact lenses: 2. Gas-permeable scleral contact lenses.

The indications and outcome of the wear of gas-permeable (GP) scleral contact lenses in 118 eyes of 85 patients attending a Scleral Contact Lens Clinic during a 5-year period from July 1988 to June 1993 were analysed. Ninety-nine eyes (83.9%) were originally fitted with PMMA lenses and were subsequently changed to GP lenses, whereas 19 (16.1%) were fitted with GP lenses from the outset. The mean duration of GP scleral lens wear was 15.3 months, with a range between 3 and 58 months. The indications for refitting the cases previously wearing PMMA scleral lenses with GP material were related to problems of chronic hypoxia. Thirty-three eyes (26.8%) had previous episodes of corneal oedema, and of the 27 that had a minimum of 3 months' follow-up, none experienced further episodes of oedema. Of the 32 eyes (26%) that had developed corneal vascularisation associated with PMMA scleral lens wear, two eyes were noted to have significant vessel regression after a period of GP wear, whereas in the remainder of cases, vessels remained static and nonprogressive. Thirty additional eyes (24.2%) experienced inadequate wear times associated with discomfort, and in these eyes the change to GP scleral lenses produced a statistically significant reduction in the inability to wear lenses beyond 4 h (p < 0.05).

Adolescent↗
PubMed1995

Iris ischaemia following penetrating keratoplasty for keratoconus (Urrets-Zavalia syndrome)

A fixed and dilated pupil is an uncommon postoperative complication after penetrating keratoplasty (PK) for keratoconus. Although the clinical features have been well described, the precise aetiology is uncertain. We performed anterior segment fluorescein angiography in the early postoperative period on three patients who developed fixed, dilated pupils after apparently uncomplicated surgery. All of the eyes had severe iris ischaemia. A possible role for a postoperative rise in intraocular pressure in the aetiology of this syndrome is discussed.

Adult↗
PubMed1994

Acute corneal hydrops in keratoconus.

PURPOSE: To determine the clinical factors associated with the development of acute corneal hydrops and its subsequent outcome. METHODS: The authors identified 147 eyes (124 patients) with acute hydrops from a database of 5242 eyes (2723 patients) with keratoconus. They compared the clinical features of patients in whom hydrops developed with unaffected patients and assessed the progression to penetrating keratoplasty by actuarial methods. RESULTS: Patients in whom acute hydrops developed tended to be younger males who had advanced corneal ectasia and a poor corrected Snellen visual acuity at the diagnosis of their keratoconus (P < 0.001). Acute hydrops also was more common in the presence of severe allergic eye disease (P < 0.001). The development of hydrops was a very significant risk factor for subsequently receiving a penetrating keratoplasty (P < 0.00001) and at the end of the study period 87 (59%) of the 147 eyes had surgery for visual rehabilitation. These eyes had a greater rate of graft rejection than eyes grafted without hydrops (P = 0.02). After resolution of the hydrops, 46 of the 60 unoperated eyes had been refitted with contact lenses, of which 28 (61%) achieved a Snellen visual acuity of 20/40 or better, although a better visual acuity often was present in the contralateral eye. Microbial keratitis developed in two of these eyes after refitting. CONCLUSIONS: Although a penetrating keratoplasty often is indicated for visual rehabilitation after acute corneal hydrops, there is an increased rate of rejection. Only a minority of eyes were re-established in contact lenses after resolution of hydrops, but some patients achieved a functional level of visual acuity such that the procedure could be delayed or avoided.

Acute Disease↗
PubMed1994

Prognostic factors for the progression of keratoconus.

PURPOSE: The progression of keratoconus to a stage where penetrating keratoplasty (PK) is required for visual rehabilitation has considerable implications for affected patients. To assist with counselling, the authors have attempted to identify which factors measurable early in the course of the disease may indicate the likelihood of subsequent surgery. METHODS: The authors reviewed the records of all patients who attended a single center over a 7-year period for contact lens management of their keratoconus. The influence of clinical variables on the time taken for the worst eye to progress to PK was evaluated by actuarial methods and multivariate analysis. RESULTS: Included in the study were 2723 patients with a mean follow-up for unoperated eyes from the first visit of 4.5 years (range, 3 months to 28 years). Data were available for multivariate analysis in 2363 patients. At the end of the study period, 757 eyes (21.6% of all patients) had been grafted. The number of eyes progressing to PK was independently related to both the maximum and minimum keratometry, a corneal cylinder of more than 1.9 mm, the Snellen acuity, the racial group (P < 0.0001), and the age at presentation (P = 0.0006). Sex, laterality, systemic atopic disease, maternal or paternal age at birth, joint hypermobility, and a family history of keratoconus were not statistically related to outcome. Progression to PK in one eye increased the risk of progression in the contralateral eye (P < 0.0001) and a linear model of disease progression is proposed. CONCLUSIONS: Several clinical variables can be measured in patients at the presentation of keratoconus that influence the probability of a subsequent PK.

Adolescent↗
PubMed1993

Eosinophil granule major basic protein deposition in corneal ulcers associated with vernal keratoconjunctivitis.

An indirect immunofluorescence assay detected eosinophil granule major basic protein in the inflammatory debris covering deepithelialized cornea in two patients with vernal keratoconjunctivitis. A slight degree of non-specific fluorescence was present in the control autopsy corneas. High concentrations of the eosinophil granule major basic protein inhibit epithelial migration and protein synthesis, whereas low concentrations affect epithelial migration. The results suggest participation of eosinophil granule major basic protein in the ulcerative process.

Blood Proteins↗
PubMed1993

The origin of keratopathy in chronic allergic eye disease: a histopathological study.

Although the clinical features of atopic keratoconjunctivitis have been well described, it is recognised that some adults with severe chronic allergic conjunctivitis do not develop a keratopathy despite having marked disease of their lid margins and conjunctiva. The aetiology of the keratopathy of chronic allergic eye disease is not known but may result from the release of toxic mediators from mast cells, eosinophils and neutrophils in the inflamed conjunctiva. To examine this theory we have counted these cells in tarsal and bulbar conjunctival biopsies from patients with severe allergic conjunctivitis and compared the numbers in samples from patients with or without keratopathy. Our results indicate that patients with chronic allergic conjunctivitis with keratopathy have higher cell numbers in their conjunctiva than patients with no keratopathy, especially those staining for eosinophil cationic protein in the tarsal epithelium. A statistically significant difference between disease groups could only be demonstrated, however, when the combined totals of mast cells, eosinophils and neutrophils were compared.

Adult↗
PubMed1993

Nedocromil sodium in contact-lens-associated papillary conjunctivitis.

Forty-five patients with contact-lens-associated papillary conjunctivitis (CLAPC) were included in a 6-week double-masked group comparative study of unpreserved 2% nedocromil sodium eye drops and placebo. Data were collected by diary card recording of symptoms and duration of lens wear, assessment of symptoms at clinic visits, biomicroscopic appraisal of signs on the globe and the upper tarsal conjunctiva, and laboratory analysis of tear and serum IgE levels. All assessments were made by the same clinician throughout the study. Diary card records demonstrated that there was significantly less itching in the nedocromil sodium group compared with the placebo group during weeks 1-3 of the study (p < 0.01), but not during weeks 4-6. Findings for duration of lens wear were inconclusive, due to differences between the groups at admission. Biomicroscopic assessment showed a significant difference in mucus found on the upper tarsal surface in favour of nedocromil sodium by the end of the study (p < 0.02). Twenty-one patients experienced adverse events during the study. The most common were taste and/or stinging on insertion of the drops. No significant difference was seen for tear or serum IgE between the two treatment groups during the study.

Adult↗
PubMed1992

Role of Staphylococcus aureus in chronic allergic conjunctivitis.

A study was undertaken to test the hypothesis that Staphylococcus aureus colonization of the lid margins could determine the expression of allergic eye disease in atopic patients. The authors compared lid isolates of S. aureus from 23 adults who had both atopic dermatitis and chronic conjunctivitis and isolates from 14 patients who had atopic dermatitis but who lacked ocular disease. No significant difference was found in either the staphylococcal protein A or hemolytic toxin production by isolates from the two disease groups, and there was no difference between groups in the quantity of serum IgG nor IgE antibodies to staphylococcal ribitol-teichoic acid. In seven patients with chronic allergic conjunctivitis who were challenged with staphylococcal protein A or heat-killed S. aureus, delayed-type hypersensitivity was not enhanced. These results suggest that although S. aureus colonization of the lids is common in atopic patients, neither the pattern of toxin production nor humoral or cell-mediated immunity to S. aureus play a role in the expression of chronic allergic conjunctivitis.

Adolescent↗
PubMed1992

Peripheral corneal oedema following cataract extraction (Brown-McLean syndrome).

We describe the clinical features of 21 eyes of 15 patients who developed peripheral bullous corneal oedema following cataract extraction. The peripheral oedema was asymptomatic in all cases and was only noted at a review examination. Although the onset of the peripheral oedema was probably delayed for several years after surgery, it was not documented to progress in any patient or to involve the central cornea. Endothelial specular microscopy did not reveal any endothelial features that are specific for this condition, but confirmed that the central endothelial cell density can be as high as 2150 cells/mm2 in the presence of peripheral corneal decompensation. Despite the surface irregularity resulting from the peripheral corneal oedema 12 patients (18 eyes) continued to wear contact lenses to correct their aphakia.

Adult↗
PubMed1992

Corneal neovascularisation in acute hydrops.

Four cases of corneal neovascularisation complicating acute hydrops in keratoconus are presented. Three cases were atopic. In two cases high doses of topical steroids failed to inhibit the neovascular process. The pathogenesis of neovascularisation in this situation is uncertain. Risk factors may be the size of the hydrops and the proximity of oedematous cornea to the limbal vascular arcades, with an associated inflammatory reaction. The coexistence of atopic keratoconjunctivitis may be an additional factor. Patients with large peripheral hydrops should be observed closely for the development of new vessels, and systemic steroids prescribed if topical medication fails to inhibit a neovascular reaction. Consideration should be given to the possibility of removing the stimulus to neovascularisation by corneal grafting, although the technical difficulties and the patients atopic state may militate against this.

Adolescent↗
PubMed1992

Life expectancy in keratoconus.

It is observed that few patients over the age of 60 regularly attend the keratoconus clinic at Moorfields Eye Hospital. The hypothesis that patients with keratoconus have a shorter life expectancy owing to underlying connective tissue related disease was tested. From patient records a sample of 337 keratoconus patients aged at least 40 years by 1991 were identified, of which 279 were living, 13 were deceased, and 45 were untraceable. The mortality rate for keratoconus patients was compared with that of the general population using actuarial English life tables. Results show no significant difference between the general population mortality rate and that of the keratoconus sample even with adjustment for social class. Possible explanations for the non-attendance of older patients are discussed.

Adult↗
PubMed1992

Myopia following penetrating keratoplasty for keratoconus.

The frequent occurrence of spherical myopia after penetrating keratoplasty for keratoconus is partly the result of the excessive dioptric power of the grafted cornea which occurs when the diameter selected for the donor button is greater than the diameter of the host incision. This excessive power could be reduced by eliminating disparity between the diameters of the graft and host. To determine what proportion of the myopia in these eyes would persist as a result of axial myopia the axial lengths of 60 patients grafted for keratoconus and 25 emmetropic controls were compared. A keratometry, objective refraction, and contact probe ultrasonic biometry were performed on all eyes. A comparison of the results with a representational schematic eye indicated that the mean spherical refractive error of the grafted keratoconic eyes (-4.83 dioptres) was the combined effect of steepness of the corneal graft (mean radius of curvature 7.46 mm) and an abnormally great axial length (mean 24.84 mm). The increased axial length was mainly the result of elongation of the posterior segment of the globe with a small contribution from an increased anterior chamber depth. Though axial myopia is common in keratoconus, a further study of 70 keratoconic eyes that had not been grafted showed no statistically significant correlation between the posterior segment length and the severity of corneal ectasia. These data suggest that even if excessive corneal power is eliminated after penetrating keratoplasty for keratoconus the associated axial myopia would still produce a mean spherical refractive error of at least -2.8 dioptres.

Adult↗