Search PubMed⌕ Search

Biomedical subjects

P E Cleary

Publications and source records attributed to P E Cleary.

At least 19 recordsLinked to original sources
PubMed2000

Visual and anatomical success with short-term macular tamponade and autologous platelet concentrate.

BACKGROUND: This study aimed to determine whether, in eyes treated for macular hole by vitrectomy and autologous platelet injection, short-term tamponade with SF6 gas was as effective as longer tamponade with C3F8 gas. METHODS: Patients in group 1 (n=31) had vitrectomy, injection of platelet concentrate, and 16% C3F8 gas/air exchange. Patients in group 2 (n=31) were similarly treated, except that 23% SF6 gas was used. Group 1 patients were required to posture prone for 2-4 weeks, group 2 for 6 days. RESULTS: All patients had 3 months' follow-up. Postoperatively, visual acuity improved faster in group 2. However, the final mean improvement in logMAR acuity was similar in both groups. Intraocular pressure (IOP) spikes occurred in 12 patients in group 2 and in 17 patients in group 1. Posterior subcapsular cataract (PSCC) occurred in 55% of cases in group 1 and in just 37% in group 2. The rate of anatomical success in group 1 was 96.7%, and in group 2, 93.5% (P=1.0). CONCLUSIONS: The combination of SF6 gas, platelet concentrate, and short-term prone posturing gave a degree of anatomical and visual success comparable to that of the group which had longer tamponade. Although no differences were statistically significant, several trends did emerge; in group 2, patients recovered visual acuity faster, had fewer IOP spikes, and there were fewer cases of PSCC formation.

Aged↗
PubMed2000

Prevention of visual field defects after macular hole surgery.

BACKGROUND/AIM: The pathogenesis of visual field loss associated with macular hole surgery is uncertain but a number of explanations have been proposed, the most convincing of which is the effect of peeling of the posterior hyaloid, causing either direct damage to the nerve fibre layer or to its blood supply at the optic nerve head. The purpose of this preliminary prospective study was to determine the incidence of visual field defects following macular hole surgery in cases in which peeling of the posterior hyaloid was confined only to the area of the macula. METHODS: 102 consecutive eyes that had macular hole surgery had preoperative and postoperative visual field examination using a Humphrey's perimeter. A comparison was made between two groups: I, those treated with vitrectomy with complete posterior cortical vitreous peeling; and II, those treated with a vitrectomy with peeling of the posterior hyaloid in the area of the macula but without attempting a complete posterior vitreous detachment. Specifically, no attempt was made to separate the posterior hyaloid from the optic nerve head. Eyes with stage II or III macular holes were operated. Autologous platelet concentrate and non-expansile gas tamponade was used. Patients were postured prone for 1 week. RESULTS: In group I, 22% of patients were found to have visual field defects. In group II, it was possible to separate the posterior hyaloid from the macula without stripping it from the optic nerve head and in these eyes no pattern of postoperative visual field loss emerged. There were no significant vision threatening complications in this group. The difference in the incidence of visual field loss between group I and group II was significant (p=0.02). The anatomical and visual success rates were comparable between both groups. CONCLUSION: The results from this preliminary study suggest that the complication of visual field loss after macular surgery may be reduced if peeling of the posterior hyaloid is confined to the area of the macula so that the hyaloid remains attached at the optic nerve head. The postoperative clinical course does not appear to differ from eyes in which a complete posterior vitreous detachment has been effected during surgery.

Adult↗
PubMed1997

Surgical management of macular holes: results using gas tamponade alone, or in combination with autologous platelet concentrate, or transforming growth factor beta 2.

BACKGROUND: Vitrectomy and gas tamponade has become a recognised technique for the treatment of macular holes. In an attempt to improve the anatomic and visual success of the procedure, various adjunctive therapies--cytokines, serum, and platelets--have been employed. A consecutive series of 85 eyes which underwent macular hole surgery using gas tamponade alone, or gas tamponade with either the cytokine transforming growth factor beta 2 (TGF-beta 2) or autologous platelet concentrate is reported. METHODS: Twenty eyes had vitrectomy and 20% SF6 gas tamponade; 15 had vitrectomy, 20% SF6 gas, and TGF-beta 2; 50 had vitrectomy, 16% C3F8 gas tamponade, and 0.1 ml of autologous platelet concentrate prepared during the procedure. RESULTS: Anatomic success occurred in 86% of eyes, with 96% of the platelet treated group achieving closure of the macular hole. Visual acuity improved by two lines or more in 65% of the SF6 only group, 33% of those treated with TGF-beta 2 and in 74% of the platelet treated group. In the platelet treated group 40% achieved 6/12 or better and 62% achieved 6/18 or better. The best visual results were obtained in stage 2 holes. CONCLUSION: Vitrectomy for macular holes is often of benefit and patients may recover good visual acuity, especially early in the disease process. The procedure has a number of serious complications, and the postoperative posturing requirement is difficult. Patients need to be informed of such concerns before surgery.

Adult↗
PubMed1994

Complications and cardiovascular risk factors in insulin-dependent diabetes--findings in an Irish clinic and in other European centres.

The Eurodiab Insulin Dependent Diabetes (IDDM) Complications Study was a cross-sectional investigation of a stratified random sample of IDDM patients attending 31 clinics in 16 European countries. We compared the findings in the only participating Irish centre (Cork Regional Hospital) with those of the study group as a whole. There were fewer episodes of ketosis but severe hypoglycaemia occurred more frequently in Cork patients, when compared to the full study group. There were no significant differences in the prevalence of background retinopathy, proliferative retinopathy, microalbuminuria, macroalbuminuria or peripheral neuropathy, when the two groups were compared. However, autonomic neuropathy was significantly less common in Cork. The prevalence of cardiovascular disease was slightly lower than the Eurodiab average in Cork patients, and cardiovascular risk factors were more favourable. Waist-hip ratio and total plasma cholesterol were significantly lower than in the full study group. The prevalence of hypertension was similar, but there were fewer smokers in Cork than in most other centres.

Adult↗
PubMed1984

Morphologic evaluation of vitreous collagen after penetrating ocular injury.

Condensation and contraction of the vitreous have been implicated in the development of vitreoretinal traction and traction retinal detachment after penetrating ocular injury. In this study, using the inorganic dye ruthenium-red, we studied ultrastructural changes in vitreous in the rabbit eye after standard penetrating injury and intravitreal blood injection. In normal rabbit vitreous the collagen fibrils have a regular arrangement. In contrast, after a penetrating injury the collagen fibrils appear focally condensed. While it appears unlikely that such a network could alone produce tractional or directional forces, these alterations along the collagen fibrils could provide a scaffold along which contractile cells migrate into the vitreous.

Animals↗
PubMed1981

Vitrectomy in penetrating eye injury. Results of a controlled trial of vitrectomy in an experimental posterior penetrating eye injury in the rhesus monkey.

A controlled trial of pars plana vitrectomy for posterior penetrating eye injury was done in rhesus monkeys. After standard injury, each eye was allocated randomly into a treatment or control group. Treatment groups (ten eyes each) had vitrectomy at 1, 14, or 70 days after injury. The control group had 15 eyes. The same techniques were employed as in human eyes. Surgical objectives were lensectomy, then complete posterior vitrectomy and excision of the anterior vitreous to within 1 or 2 mm of the surface of the peripheral retina and pars plana. Results from this controlled trial provide strong support for the effectiveness of vitrectomy techniques in managing selected posterior penetrating injuries in human eyes and in preventing the complication of traction retinal detachment.

Animals↗
PubMed1981

Mechanisms in traction retinal detachment.

We have developed a reproducible model of traction retinal detachment in the rhesus monkey secondary to a penetrating eye injury. The model is characterized histologically by intravitreal fibroblastic proliferation and by epiretinal and by retroretinal membranes. Cells proliferating within the vitreous and in the epiretinal membranes have the ultrastructural characteristics of myofibroblasts. The presence of these contractile cells suggests that vitreous traction and the contraction of epiretinal membranes may be cell mediated. Our findings suggest that the pathophysiology of traction retinal detachment has many features in common with the normal process of wound healing and in particular with the mechanisms responsible for wound contraction and cicatrization.

Animals↗
PubMed1980

Bright-flash electroretinography and vitreous hemorrhage. An experimental study in primates.

Serial, bright-flash electroretinograms (ERGs) were recorded from rhesus monkey eyes before and after a standard posterior penetrating ocular injury and injection of 0.5 mL of blood into the vitreous. This procedure resulted in a progressive depression to virtual nonrecordability of the ERG during a period of several weeks, owing to a combined progressive increase in optical density and loss of retinal function. The ERG depression, however, was reversible, showing a remarkable recovery during the subsequent four to eight weeks. These findings suggest that in the presence of a recent, massive vitreous hemorrhage, a nonrecordable bright-flash ERG does not necessarily indicate a permanent loss of retinal function.

Animals↗
PubMed1980

Ultrastructure of traction retinal detachment in rhesus monkey eyes after a posterior penetrating ocular injury.

We studied the ultrastructural characteristics of an experimental model of traction retinal detachment secondary to a penetrating eye injury in the rhesus monkey. Cells with the characteristics of myofibroblasts were present in the intravitreal fibrous tissue and in epiretinal membranes. These cells were probably derived from many sources, and were capable of contraction through the mechanism of intracytoplasmic contractile proteins such as actin or myosin. The morphologic observations supported our hypothesis that traction retinal detachment is a cell-mediated event analogous to the processes of wound healing and wound contraction. The force of contraction is mediated by cell-to-cell and cell-to-vitreous connections and by glial bridges that connect epiretinal membranes to the retina. These ultrastructural studies, which provide insight into the pathogenesis of traction retinal detachment in the experimental animal model, may well have significant clinical relevance.

Animals↗
PubMed1980

Experimental posterior penetrating eye injury in the rhesus monkey: vitreous-lens admixture.

A standardised experimental posterior penetrating eye injury in the rhesus monkey with the vitreous-lens admixture resulted in limited fibrous ingrowth from the wound and minimal traction on the peripheral retina. Microscopically inflammation was noted in the iris, ciliary body, and as a perivascular infiltrate of the inner retina. Periretinal membranes did not occur, and cellular proliferation within the vitreous was less marked than observed after an identical wound and simulated vitreous haemorrhage in previously reported studies. The lens may be a less important stimulus to intravitreal fibroblastic proliferation than previously assumed.

Animals↗