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Biomedical subjects

G W Aylward

Publications and source records attributed to G W Aylward.

At least 19 recordsLinked to original sources
PubMed2001

How to predict proliferative vitreoretinopathy: a prospective study.

PURPOSE: To determine prospectively the accuracy of a predictive risk formula for the development of postoperative proliferative vitreoretinopathy (PVR) when applied in a clinical setting. DESIGN: Prospective noncomparative interventional case series. PARTICIPANTS: Two hundred nineteen subjects undergoing primary vitrectomy for rhegmatogenous retinal detachment were studied. METHOD: By use of a formula-based discriminant rule, subjects were classified as either high or low risk for the development of PVR. All subjects were followed prospectively. OUTCOME MEASURES: Development of postoperative PVR as defined by the updated the Retina Society Classification. RESULTS: Complete data were available on 212 of 219 subjects. There were 130 subjects identified as low risk and 82 subjects as high risk; 9.2% of the low-risk (12 of 130) compared with 28% (23 of 82) of the high-risk subjects had postoperative PVR develop. This difference was statistically significant (P < 0.001). CONCLUSIONS: Our study has shown that using a clinical model it is possible to identify subjects at greater risk of PVR developing after primary vitrectomy.

Adolescent↗
PubMed2001

Adjuvant 5-fluorouracil and heparin prevents proliferative vitreoretinopathy : Results from a randomized, double-blind, controlled clinical trial.

PURPOSE: To assess the safety and efficacy of adjuvant combination therapy using 5-fluorouracil (5-FU) and low molecular weight heparin (LMWH) for prevention of proliferative vitreoretinopathy (PVR) after vitrectomy and retinal reattachment surgery. DESIGN: Prospective randomized, double-masked, placebo controlled trial. PARTICIPANTS: One hundred seventy-four high-risk patients were randomized to receive either 5-FU and LMWH therapy or placebo. Patients were selected from all patients undergoing primary vitrectomy for rhegmatogenous retinal detachment. METHOD: Results of standard surgery with 5-FU and LMWH therapy or placebo were compared at the 6-month follow-up. MAIN OUTCOME MEASURES: Development of postoperative PVR, retinal reattachment at 6 months after surgery, single operation reattachment rate, number of reoperations, and best-corrected visual acuity. RESULTS: There were 87 patients in the 5-FU and LMWH therapy group and 87 in the placebo group. The incidence of postoperative PVR was significantly lower (P = 0.02) in the 5-FU and LMWH therapy compared with the placebo group. In 26.4% (23/87) of the placebo group and in 12.6% (11/87) of the 5-FU and LMWH group, postoperative PVR developed. In the 5-FU and LMWH group, the number of patients undergoing more than one operation was 19.5% (17/87) and the number of reoperations resulting from PVR was 52.9% (9/17). In the placebo group, the number of patients undergoing more than one operation was 25.3% (22/87) and the number of reoperations resulting from PVR was 72.7% (16/22). The difference in visual acuity was not statistically different in the two treatment groups, although those patients in whom postoperative PVR developed tended to have poorer vision (P < 0.0001). There were no differences in complication rates between the two groups. CONCLUSIONS: There is a significant reduction in the incidence of postoperative PVR in patients receiving the 5-FU and LMWH therapy and in the reoperation rate resulting from PVR. This trial shows that incidence of PVR can be reduced with inexpensive and simple pharmacologic treatment with 5-FU and LMWH and should be used routinely in the treatment of patients at risk of developing PVR.

Adolescent↗
PubMed2001

Retinal pigment epithelium translocation and central visual function in age related macular degeneration: preliminary results.

PURPOSE: To test the feasibility of a new surgical technique, and to assess visual function over the translocated retinal pigment epithelium (RPE) cells in patients operated upon for subfoveal choroidal neovascularization (CNV) secondary to age-related macular degeneration (AMD). MATERIALS AND METHODS: Six patients presenting previously untreated exudative AMD underwent surgical excision of the subfoveal CNV with RPE translocation and were followed from 1 to 10.5 months. The surgery consisted of a standard three port pars plana vitrectomy (TPPPV), excision of the CNV and RPE translocation. Pre and post-operative ocular examination included best-corrected visual acuity measurement, fundus color stereo photography and fundus fluorescein angiography. Optical coherence tomography (OCT) and confocal laser scanning ophthalmoscopy (cLSO) were performed post-operatively. A cross fixation target and a single-point flashing light were projected on different areas of the posterior pole using a cLSO. Photopic 10-2 perimetry, photopic fine matrix mapping, cLSO microperimetry were also performed pre and post-operatively in four patients. OCT cross-sectional scans and cLSO RPE autofluorescence were recorded to detect the presence of viable translocated RPE. Visual acuity, fixation, photopic 10-2 perimetry, photopic fine matrix mapping and cLSO microperimetry were tested for the presence of central visual function. RESULTS: RPE could be effectively translocated at the time of CNV removal from the edge of the RPE defect to a subfoveal location. OCT showed the translocated RPE as an area of increased optical reflectivity with optical shadowing external to it. cLSO showed autofluorescence of the translocated RPE. The cross fixation target was seen when projected on the translocated RPE. During eccentric fixation, the patients could see a flashing point-target projected on the translocated RPE. Photopic 10-2 perimetry, photopic fine matrix mapping and cLSO microperimetry showed presence of central visual function. CONCLUSIONS: The authors propose that translocation of RPE at the time of CNV removal, from the edge of the RPE defect to a subfoveal location, may have a role in the surgical management of AMD.

Aged↗
PubMed2001

The effect of pars plana vitrectomy in the management of Fuchs heterochromic cyclitis.

PURPOSE: Fuchs heterochromic cyclitis (FHC) is characterized by a unilateral chronic iridocyclitis of insidious onset and uncertain cause. Our aim was to evaluate the effect of vitreous surgery in patients with FHC and clinically significant visual symptoms caused by inflammatory vitreous debris. METHODS: This study was a review of 12 eyes of 12 consecutive patients with FHC who underwent pars plana vitrectomy for visually significant vitreous opacities. Cataract extraction with posterior chamber lens implantation had been performed on four eyes preoperatively. Four eyes had a concomitant lensectomy for cataracts, and one had a surgical posterior capsulotomy. Visual and anatomic data were recorded before surgery and for at least 6 months after surgery. RESULTS: Visual acuity improved in all patients from an average logMAR of 0.57 to 0.007 (P = 0.0004) and by more than 2 Snellen lines in 8 of 12 of the eyes (P < 0.05). Symptoms of floaters resolved in all 11 patients in whom they were a symptom. Vitreous haze was cleared completely from an average Nussenblatt grade of 1.7 to 0 after 1 week (P = 0.0001). CONCLUSIONS: Pars plana vitrectomy is a safe and effective treatment for the visual symptoms associated with FHC and can be combined safely with a lensectomy if required.

Adult↗
PubMed2001

Screening for retinal detachment.

There is a reasonable basis for examination of patients with acute symptoms of posterior vitreous detachment, and this is current practice for patients who present with such symptoms. Significant morbidity is associated with detachment of the macula before treatment of retinal detachment, and in most cases, this occurs before presentation. There may be benefit in public information campaigns in an attempt to encourage patients to present earlier. A small reduction in the proportion of patients who present for surgery with a detached macula would produce a significant decrease in visual morbidity. With the current state of evidence, however, there is no justification for the general screening of patients for retinal detachment, or for predisposing lesions.

Humans↗
PubMed2000

Visual outcome after silicone oil removal and recurrent retinal detachment repair.

PURPOSE: Prospective analysis of the effect of removal of silicone oil (ROSO) in eyes with complicated retinal detachments and evaluation of the visual outcome following recurrent retinal detachment after silicone oil removal. METHODS: We evaluated 62 consecutive cases of ROSO over a 12 month period. All eyes had previously undergone silicone oil placement for complicated retinal detachments. All eyes undergoing scheduled ROSO over the time period of the study were entered and were reviewed post-operatively. RESULTS: Sixty-two eyes were entered into the study. Twenty-one of 62 (34%) developed recurrent retinal detachment following ROSO; 18 of these 21 recurrent detachments were reattached with one additional procedure and only 5 required replacement of the silicone oil. Ten of these 21 eyes (48%) had improvement or stabilisation in final visual acuity compared with the presenting visual acuity. Overall, 39 eyes (63%) had improvement in vision following ROSO and 76% of all eyes had ambulatory visual acuity at the end of the follow-up period. Fourteen eyes required cataract extraction with ROSO to attain this final visual acuity. CONCLUSIONS: Overall, ROSO has a significant rate of recurrent retinal detachment, with a high reattachment rate with one additional procedure. Few of these eyes need the silicone oil replaced. Most eyes will retain ambulatory visual acuity even with multiple procedures in cases of complicated retinal detachments following ROSO even with recurrent retinal detachment.

Adolescent↗
PubMed2000

Risk factors for proliferative vitreoretinopathy after primary vitrectomy: a prospective study.

AIM: To assess clinical variables and vitreous protein as risk factors for the development of postoperative proliferative vitreoretinopathy (PVR). METHODS: A prospective study was conducted on 140 patients with a rhegmatogenous retinal detachment in whom a primary vitrectomy was performed. 12 clinical variables were recorded and vitreous samples obtained for measurement of protein concentration. Univariate and multivariate logistic regression analysis was used to determine the risk factors for PVR. RESULTS: Complete data were available for 136 of 140 patients. 40 of the 136 patients (29.4%) developed postoperative PVR. Univariate regression revealed that significant (p<0.05) risk factors included aphakia, presence of preoperative PVR, size of detachment, the use of silicone oil, and high vitreous protein level. Multivariate regression analysis revealed only aphakia (odds ratio 2.72), the presence of preoperative PVR (odds ratio 3.01), and high vitreous protein concentration (odds ratio 1.11) to be significant (p<0.05) independent, predictive risk factors for the development of PVR. CONCLUSIONS: This study has shown that the significant risk factors for PVR are preoperative PVR, aphakia, and high vitreous protein levels. Two models (clinical factors only and clinical factors and vitreous protein) were constructed to predict the probability of developing postoperative PVR and may be used to identify those at risk for possible intravitreal pharmacological treatment.

Adolescent↗
PubMed1999

Expression of vitreous cytokines in proliferative vitreoretinopathy: a prospective study.

PURPOSE: Proliferative vitreoretinopathy (PVR) is a major cause of failure of retinal detachment surgery. It is believed to be a wound-healing process in the retina. Many of the cellular functions are influenced by cytokines and growth factors such as interleukins (ILs). The present study was conducted to investigate the presence of transforming growth factor-beta 2 (TGF-beta2), basic fibroblast growth factor (bFGF), IL-1beta, IL-6, and protein in the vitreous of patients with retinal detachment and to determine the value of these mediators in predicting the future development of PVR. METHODS: A prospective study was conducted in 140 consecutive patients with rhegmatogenous retinal detachment in whom vitrectomy was considered necessary. Vitreous samples were analyzed for the presence of TGF-beta2, bFGF, IL-1beta, IL-6, and protein. Patients were then followed up for 3 months for the development of postoperative PVR. RESULTS: The mean levels of TGF-beta2, bFGF, IL-1beta, and protein in the vitreous were significantly higher (P < 0.05) in patients with preoperative PVR compared with those without. The mean levels of TGF-beta2, bFGF, IL-6, and protein in the vitreous were significantly higher (P < 0.05) in patients who had postoperative PVR compared with those who did not. Multivariate logistic regression analysis showed IL-6 and protein to be significant (P < 0.05), independent, predictive risk factors for the development of PVR. CONCLUSIONS: The various cytokines may play a role in the pathobiology of PVR. High vitreous levels of IL-6 and protein were identified as significant risk factors for PVR. A model was developed to predict the probability of development of postoperative PVR in these patients, and it may be used to indicate intravitreal pharmacologic treatment for those at risk.

Adolescent↗
PubMed1998

A long-term follow-up of choroidal osteoma.

OBJECTIVE: To provide long-term follow-up information on a large series of patients with choroidal osteoma. METHODS: Review of patients with a diagnosis of choroidal osteoma who had been examined at the Bascom Palmer Eye Institute, Miami, Fla, or known to one of us (J.D.M.G.). Information was obtained from hospital medical records or by a questionnaire sent to referring ophthalmologists. Life-table analysis was used to study the loss of vision and development of choroidal neovascularization. RESULTS: We followed up 36 patients, 31 (89%) were female, mean age, 21 years (range, 5-54 years) for a mean of 10 years (range, 2-22 years). Growth was observed for 9 (41%) of 22 well-documented osteomas. The probability of loss of visual acuity to 20/200 or worse was 58% by 10 years and 62% by 20 years. The probability of developing choroidal neovascularization was 47% by 10 years and 56% by 20 years. Successful treatment of the choroidal neovascularization with laser photocoagulation was performed for 5 (25%) of 20 patients. CONCLUSIONS: Most patients with choroidal osteomas maintain good vision in at least 1 eye, but they have a high risk of developing choroidal neovascularization. When this occurs, only a minority can be successfully treated with laser photocoagulation.

Adolescent↗
PubMed1998

The management of dislocated lens material after phacoemulsification.

PURPOSE: To determine the visual outcome, prognostic factors, and effect of timing of surgical intervention in patients with retained lens fragments after phacoemulsification. METHODS: A retrospective review was carried out of the notes of 44 consecutive patients who suffered posterior dislocation of lens fragments during phacoemulsification, of whom 34 underwent vitrectomy. RESULTS: The presence of severe uveitis at presentation was a significant predictor of a final visual acuity of less than 6/60 (p = 0.002). A raised intraocular pressure at presentation (> 29 mmHg) significantly increased the risk of chronic glaucoma (p = 0.0279), but there was no association between glaucoma and delay in vitrectomy. Patients operated on within 1 week of cataract surgery obtained a better visual outcome (64.7%) of patients achieved 6/12 or better visual acuity) than those operated on later than 1 week (41% obtained 6/12), but this difference did not reach statistical significance. CONCLUSIONS: The trend towards a better visual outcome with early vitrectomy was not statistically significant. A large prospective trial is indicated to determine the optimum time for vitrectomy in these patients.

Adult↗
PubMed1998

Effects of single, short-term exposures of human retinal pigment epithelial cells to thiotepa or 5-fluorouracil: implications for the treatment of proliferative vitreoretinopathy.

AIM: To investigate the effects of single, short-term (5 or 30 minutes) exposures to thiotepa or 5-fluorouracil (5-FU) on collagen lattice contraction and retinal pigment epithelial (RPE) cell proliferation. METHODS: For collagen contraction studies, RPE cells seeded into free floating type I collagen lattices were exposed to single 5 or 30 minute treatments with thiotepa (0.06-4 mg/ml), or 5-FU (0.25-25 mg/ml), or phosphate buffered saline alone as a control. For proliferation studies, RPE cell monolayers were similarly exposed to these agents. The degree of contraction, effects on cell number, and viability were determined up to 14 days after treatment. RESULTS: Contraction of collagen lattices containing RPE cells and proliferation of RPE cells were significantly inhibited (p < 0.05) by thiotepa and 5-FU at concentrations above 0.06 mg/ml and 0.25 mg/ml respectively (for both 5 and 30 minute treatments), compared with controls. Cell death did not occur except for exposure of the RPE cells in collagen lattices to the highest concentration of thiotepa (4 mg/ml). CONCLUSION: It was concluded that single 5 or 30 minute exposures to thiotepa or 5-FU significantly inhibited collagen contraction and the proliferation of RPE cells. These findings suggest that short, single, non-toxic exposures to thiotepa or 5-FU which can be reproduced clinically may be useful in the modulation of proliferative vitreoretinopathy.

Alkylating Agents↗