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Biomedical subjects

G A Williams

Publications and source records attributed to G A Williams.

At least 19 recordsLinked to original sources
PubMed2000

Effect of perifoveal tissue dissection in the management of acute idiopathic full-thickness macular holes.

OBJECTIVE: To evaluate the efficacy of perifoveal tissue dissection (PTD) on patients undergoing pars plana vitrectomy for idiopathic macular holes of less than 1-year's duration. METHODS: Pars plana core vitrectomy was performed on 107 eyes of 104 consecutive patients with acute idiopathic macular holes. One cohort had routine PTD. In the other cohort, no attempt was made to strip preretinal tissue. Follow-up was longer than 6 months (follow-up range, 6 to 36 months). RESULTS: Overall, 95 (89%) of all macular holes were closed. Visual acuity improved 2 lines or more of the Snellen letter chart in 91 eyes (85%). A postoperative visual acuity of 20/50 or better was achieved in 79 eyes (74%). A transient increase in intraocular pressure (230 mm Hg) developed in 25 eyes (23.4%). In 6 eyes (5.6%) a retinal detachment developed. One eye had retinal pigment epithelial changes and 1 patient reported peripheral field loss. No statistically significant differences were noted between eyes having PTD and those without PTD for any outcome measure. CONCLUSION: In this series, no beneficial or adverse effect could be demonstrated by performing PTD in eyes undergoing pars plana core vitrectomy for acute idiopathic macular holes.

Acute Disease↗
PubMed2000

Nonsurgical management of macular hemorrhage secondary to retinal artery macroaneurysms.

OBJECTIVE: To report visual acuity outcomes of nonsurgical management of macular hemorrhage secondary to retinal artery macroaneurysms. METHODS: Forty-one patients at multiple centers with macular hemorrhage secondary to retinal artery macroaneurysms managed with observation alone were reviewed. Time to clearance of macular hemorrhage, visual acuity at final follow-up, and presence or absence of macular pigmentary changes after absorption of the hemorrhage were recorded for each patient. RESULTS: On initial examination, visual acuity was 20/200 or worse in all except 4 patients (3 with 20/70, 1 with 20/80). At an average follow-up of 15. 7 months, a final visual acuity of 20/40 or better was achieved in 15 eyes (37%), between 20/50 and 20/100 in 12 (29%), and 20/200 or worse in 14 (34%). Macular pigmentary abnormalities were noted after clearance of the hemorrhage in 23 (56%) of 41 cases, and these eyes generally had worse visual acuity outcomes. CONCLUSIONS: In eyes with macular hemorrhage secondary to retinal artery macroaneurysms managed with observation alone, good visual acuity outcomes can often be achieved. Poorer visual acuity outcomes are associated with macular pigmentary changes after resorption of blood. Arch Ophthalmol. 2000;118:780-785

Adult↗
PubMed2000

A new approach to stage 3 macular holes.

PURPOSE: The purpose of this article is to demonstrate the feasibility of a surgical approach that might be possible in an office setting for idiopathic stage 3 macular holes. The posterior hyaloid of the vitreous and perihole tissue is enzymatically manipulated to create an atraumatic posterior vitreous separation and may stimulate cell proliferation to close macular holes. DESIGN: Prospective noncomparative interventional case series. PARTICIPANTS: Nine eyes of eight patients with idiopathic stage 3 macular holes were treated. METHODS: The patients were treated with an injection of 0.4 IU of autologous plasmin enzyme into the midvitreous cavity and lavage of the vitreous cavity with an infusion light pipe and vitreous cutter followed by filling 70% to 80% of the vitreous cavity with 14% C3F8 and head-down positioning. MAIN OUTCOME MEASURES: Posterior vitreous detachment, macular hole closure, and vision improvement. RESULTS: Eight of nine eyes showed a spontaneous posterior vitreous detachment. One eye required minimal suction of less than 50 mmHg to elevate the posterior hyaloid off the retinal surface. Eyes were followed for a minimum of 6 months. All holes closed, and there was an average visual acuity improvement of four lines. The average surgical time for this procedure was 20 minutes. CONCLUSIONS: Autologous plasmin enzyme-assisted vitreous surgery techniques can reduce operative time, expense, and patient inconvenience while maintaining excellent surgical results, which may allow office-based vitreous surgery for idiopathic stage 3 macular holes.

Aged↗
PubMed1999

Results after lens extraction in patients with diabetic retinopathy: early treatment diabetic retinopathy study report number 25.

OBJECTIVE: To assess the visual results after surgical lens removal in patients with diabetic retinopathy. DESIGN: A multicenter randomized clinical trial designed to assess the effect of photocoagulation and aspirin in patients with mild to severe nonproliferative or early proliferative diabetic retinopathy and/or macular edema. PARTICIPANTS: Of the 3711 patients enrolled in the Early Treatment Diabetic Retinopathy Study, lens surgery was performed on 205 patients (270 eyes) during follow-up that ranged from 4 to 9 years. OUTCOME MEASUREMENTS: Visual acuity, macular edema status, and degree of diabetic retinopathy. In addition, risk factors associated with lens extraction and with poor postoperative visual acuity (worse than 20/100) were assessed. RESULTS: The risk of lens extraction increased with increasing age, female sex, and baseline proteinuria. Ocular variables associated with increased risk of lens surgery included poor baseline visual acuity and vitrectomy performed during the course of the study. At 1 year after lens surgery, visual acuity improvement of 2 or more lines from preoperative levels occurred in 64.3% of the operated-on eyes assigned to early photocoagulation and 59.3% of eyes assigned to deferral of photocoagulation. In eyes assigned to early photocoagulation, 46% of eyes achieved visual acuity better than 20/40; 73%, better than 20/100; and 8%, 5/200 or worse at 1 year after surgery. Visual acuity results for eyes assigned to deferral of laser photocoagulation at 1 year were not as favorable; 36% achieved visual acuity better than 20/40; 55%, better than 20/100; and 17%, 5/200 or worse at 1 year after surgery. Evaluation of 1-year postoperative visual acuities for all eyes with mild to moderate nonproliferative diabetic retinopathy at the annual visit before lens surgery showed that 53% were better than 20/40; 90%, better than 20/100; and 1%, 5/200 or worse. However, for eyes with severe nonproliferative or worse retinopathy at the annual visit before lens surgery, only 25% were better than 20/40; 42%, better than 20/100; and 22%, 5/200 or worse at 1 year after lens surgery. There was little change in visual acuity between 1 and 2 years postoperatively. Increased severity of retinopathy and poor visual acuity before surgery were associated with visual acuity of worse than 20/100 at 1 year after surgery. Lens surgery was associated with a borderline statistically significant increased risk of progression of diabetic retinopathy in the adjusted analyses (P = .03). No statistically significant long-term increased risk of macular edema was documented after lens surgery. CONCLUSIONS: Visual acuity results after lens surgery in patients in the Early Treatment Diabetic Retinopathy Study were better than published results for similar patients. This may be because of more intensive photocoagulation for lesions of diabetic retinopathy in the Early Treatment Diabetic Retinopathy Study than in previously reported studies. Although patients with severe nonproliferative retinopathy or worse before lens surgery had poorer visual results, visual improvement was seen in 55% of these patients at 1-year follow-up. The main causes of poor visual results in eyes after lens surgery were complications of proliferative retinopathy and/or macular edema.

Aspirin↗
PubMed1999

Vitrectomy for chronic pseudophakic cystoid macular edema.

PURPOSE: We report the results of pars plana vitrectomy for chronic pseudophakic cystoid macular edema unresponsive to medical treatment. METHODS: Retrospective analysis of 23 consecutive eyes of 23 patients with chronic pseudophakic cystoid macular edema was performed. Eyes with vitreous incarceration into the cataract wound or vitreous-cornea contact were excluded from the study. Preoperatively, all eyes had cystoid macular edema confirmed on fluorescein angiography and were unresponsive to medical treatment. Pars plana vitrectomy was performed using standard techniques and vitreous adhesions to the iris, intraocular lens, or both were lysed if present. RESULTS: The mean interval between cataract surgery and vitrectomy was 32.3+/-30.9 months (median, 20 months; range, 3 to 110 months). The vitreous was adherent to the iris or intraocular lens in 12 eyes (52.2%) and was present in the anterior chamber with no evidence of adhesions in seven eyes (30.4%). In four eyes (17.4%) the vitreous was posterior to the iris plane with no adhesions to anterior segment structures. The median preoperative best-corrected visual acuity was 20/200, and the median final postoperative best-corrected visual acuity was 20/60 (P<.0001) after a mean follow-up of 30.2+/-31.2 months (median, 14 months; range, 2 to 109 months). Final best-corrected visual acuity improved by a mean of 3.3+/-2.6 Snellen lines, with a median percent change of 70% (mean, 57.3%; range, 0% to 99%). In all 23 eyes the cystoid macular edema resolved postoperatively by biomicroscopic examination in a mean period of 3.3 months (median, 2 months; range, 1 to 12 months). CONCLUSIONS: In pseudophakic eyes with chronic cystoid macular edema unresponsive to medical treatment, vitrectomy resulted in resolution of the cystoid macular edema with improved visual acuity in some cases. Clinical improvement may occur in eyes with no apparent vitreous disturbance.

Aged↗
PubMed1999

Potential utility of left heart contrast agents in diagnosis of myocardial rupture by 2-dimensional echocardiography.

This case illustrates the use of intravenous injections of a contrast agent during 2-dimensional echocardiography in a patient with myocardial rupture after myocardial infarction. Intravenous injections of echocardiographic contrast agents may have potential use in the identification of intrapericardial hemorrhage after myocardial infarction caused by myocardial rupture or development of ventricular pseudoaneurysm.

Aged↗
PubMed1999

Successful closure of traumatic macular holes.

PURPOSE: To establish the efficacy of vitreoretinal surgery without the use of transforming growth factor-beta or autologous platelet concentrate in the repair of traumatic macular holes. METHODS: This retrospective review consisted of 16 eyes from 16 consecutive patients treated by five vitreoretinal surgeons at a single institution between 1993 and 1997. Intervention included pars plana vitrectomy with creation of posterior vitreous detachment, placement of 14% to 16% C3F8 gas, and postoperative face-down positioning. Ten eyes received intraoperative autologous plasmin to facilitate formation of posterior vitreous detachment. Main outcome measures were anatomic closure rate and visual outcome. RESULTS: Anatomic closure of the macular holes was achieved in 15 (94%) of 16 eyes, with an average follow-up of 7 months. Six (38%) eyes achieved visual acuity of 20/40 or better. Visual acuity improved by 2 or more lines in 11 (69%) of 16 eyes. The average preoperative logMAR-converted visual acuity of 20/175 improved to 20/60 postoperatively. CONCLUSION: Traumatic macular holes can be closed successfully with substantial visual recovery without the use of transforming growth factor-beta or platelet concentrate.

Adolescent↗
PubMed1999

Human diabetic neovascular membranes contain high levels of urokinase and metalloproteinase enzymes.

PURPOSE: Retinal neovascularization is one of the leading causes of blindness. A crucial event in this process is the remodeling and penetration of the capillary basement membrane by migrating endothelial cells. This process requires proteolysis of basement membrane components by a variety of proteinases. The objective of the present study was to determine the expression of proteinases in human retinal tissues showing active neovascularization. METHODS: Epiretinal neovascular membranes surgically removed from patients with proliferative diabetic retinopathy were analyzed by zymography, and the types and amounts of proteinases present in the tissues were determined. Retinas from nondiabetic donor eyes served as control specimens. RESULTS: Both the high- (54 kDa) and low- (33 kDa) molecular-weight forms of urokinase were present at significantly higher levels in neovascular membranes than in normal retinas. The pro forms of the matrix metalloproteinases (MMP) MMP-2 and MMP-9 were significantly elevated in the neovascular membranes in comparison with levels in normal retinas. In addition, the active forms of these enzymes were present in the membranes, whereas there was no detectable level of the active forms in normal retinas. CONCLUSIONS: Human diabetic neovascular membranes contain high levels of urokinase and MMP. The increased activity of proteinases in the final common pathway of retinal neovascularization indicates that inhibition of these enzymes may be a useful therapeutic target as an alternative approach in the management of proliferative retinopathies.

Aged↗
PubMed1998

Comparison of recombinant transforming growth factor-beta-2 and placebo as an adjunctive agent for macular hole surgery.

OBJECTIVE: This study aimed to compare the visual and anatomic results of macular hole surgery in eyes treated with recombinant transforming growth factor-beta-2 (TGF-beta2) or placebo. DESIGN: The design was a prospective, multicenter, randomized, double-masked, placebo-controlled clinical study. PARTICIPANTS: One hundred thirty eyes with idiopathic macular holes of 1 year or less and a refracted Early Treatment Diabetic Retinopathy Study visual acuity of 20/80 or worse were treated with 1.1 microg recombinant TGF-beta2 or placebo to the macular hole after fluid-gas exchange. INTERVENTION: The effect of recombinant TGF-beta2 as an adjunctive agent for macular hole surgery was evaluated. MAIN OUTCOME MEASURES: Closure of the macular hole and change in visual acuity at 3 months were measured. RESULTS: The 3-month visits were completed for 120 eyes. The macular hole was closed at 3 months in 35 (61.4%) of 57 eyes treated with placebo and 49 (77.8%) of 63 eyes treated with recombinant TGF-beta2 (P = 0.08). The mean visual acuity gain was +6.4 letters in eyes receiving placebo and +8.9 letters in eyes treated with recombinant TGF-beta2 (P = 0.27). Visual acuity improved 2 or more lines in 23 (40.4%) of 57 eyes treated with placebo and 30 (47.6%) of 63 eyes treated with recombinant TGF-beta2 (P = 0.42). Intraocular pressure elevation greater than 30 mmHg was more common 2 weeks after surgery in eyes treated with recombinant TGF-beta2 (P < 0.001). CONCLUSIONS: Recombinant TGF-beta2 resulted in a similar proportion of successful closure of macular holes as placebo. There was no statistically significant visual acuity benefit with the use of recombinant TGF-beta2 for the treatment of macular holes.

Aged↗
PubMed1998

Plasmin enzyme-assisted vitrectomy in traumatic pediatric macular holes.

OBJECTIVE: This study aimed to evaluate the benefit of plasmin enzyme-assisted macular hole surgery on a consecutive series of pediatric patients with traumatic macular holes. DESIGN: Prospective noncomparative case series operated on at William Beaumont Hospital between July 13, 1996, and November 16, 1996, and observed for at least 6 months. PARTICIPANTS: During this interval, the authors operated on four eyes from four consecutive patients who were 14 years of age or younger with traumatic macular holes. INTERVENTION: The patients underwent plasmin enzyme-assisted pars plana vitrectomy with membrane peeling, fluid-gas exchange, and postoperative positioning. The enzyme used was 0.4 international unit (IU) of autologous plasmin enzyme. MAIN OUTCOME MEASURES: Snellen lines of improvement in visual acuity and rate of final visual acuity of 20/40 or greater, and incidence of complications and reoperations were measured. RESULTS: All four macular holes were closed successfully. Follow-up was from 6 to 12 months. There were no reoperations. Visual acuity improved from four to eight lines in all eyes. Three eyes (75%) achieved a postoperative visual acuity of 20/40 or better. Three eyes (75%) had transient, posterior, subcapsular cataracts develop: two of the eyes after surgery and one as a result of the initial injury. CONCLUSION: The treatment of pediatric traumatic macular holes with plasmin enzyme-assisted vitrectomy, membrane peeling, and gas-fluid exchange resulted in closure of the macular holes with significant visual improvement.

Adolescent↗
PubMed1998

Good visual acuity in an adult population with marked posterior segment changes secondary to retinopathy of prematurity.

PURPOSE: To show that good visual acuity can be compatible with marked posterior segment changes secondary to retinopathy of prematurity (ROP) in the adult population. METHODS: A retrospective chart review of adult patients with regressed ROP. We found 14 eyes in 12 patients who were older than 21 years with a visual acuity of 20/60 or better associated with marked posterior segment changes secondary to ROP. RESULTS: Of the 14 eyes, 11 were myopic, with six eyes having the spherical equivalent of > or = -6.00. Best-corrected visual acuities ranged from 20/15-20/60. One eye had a macular fold. Thirteen eyes had macular ectopia. CONCLUSIONS: Good vision can be compatible with marked posterior segment changes secondary to ROP in an adult population. This emphasizes the need to follow these patients closely during childhood and treat them promptly for any amblyogenic condition that could prevent them from reaching their full visual potential.

Adult↗
PubMed1998

Adrenoleukodystrophy: unusual clinical and radiographic manifestation.

Adrenoleukodystrophy is an X-linked recessive peroxisomal disorder, characterized by progressive neurologic deterioration due to cerebral white matter demyelination and adrenal insufficiency. Onset is usually in childhood between ages 5 and 10, and its course is fatal within approximately 5 years. Initial symptoms are behavioral, gait, and auditory disturbances and may be a diagnostic dilemma. Abnormally raised plasma very long chain fatty acids (VLCFA) are diagnostic; computed tomography and magnetic resonance imaging findings show symmetrical occipital white matter lesions which progress in a rostralcaudal direction.

Adolescent↗
PubMed1998

Video technology and children's evidence: international perspectives and recent research.

Research has shown that children can be as competent and reliable as adults as eyewitnesses of crime, if questioned in an appropriate manner. However, there is considerable variation between, and within, countries in the way in which child witness evidence is accepted in criminal cases. This article reviews the legal facilities that exist for young witnesses in countries such as the United States, England & Wales, Canada and Australia. Particular emphasis is placed on recent research into the use of video technology by the courts in child abuse cases--namely testimony with a live video link or a pre-recorded interview in place of live, open court evidence. Studies into the use of live link and videotaped interviews have shown that these innovations could help to reduce the trauma of testifying for children and could lead to better quality evidence from the child. However, there is considerable concern among legal and child protection professionals about the relative lack of impact of video testimony when compared with live, in-court testimony. Research has uncovered significant support among legal professionals towards using curtained partitions 'screens' to allow a child witness to testify within the courtroom without allowing the child to see, or be distracted by, the accused. There is also widespread concern about the questioning techniques used in videotaped interviews and with the live link. Future implications for the use of video testimony are also discussed.

Adolescent↗
PubMed1997

Vitrectomy for retained lens fragments after phacoemulsification.

PURPOSE: Posterior lens fragments after phacoemulsification can be a serious complication of cataract surgery. This study is designed to evaluate the clinical features of eyes after pars plana vitrectomy has been performed to remove posteriorly dislocated lens fragments after phacoemulsification. METHODS: The authors performed a retrospective chart review of 126 consecutive eyes of 126 patients with dislocated lens fragments after phacoemulsification, managed with pars plana vitrectomy at Associated Retinal Consultants of Michigan. These eyes were operated on from January 1986 through January 1996. RESULTS: The relation of the intervals between cataract surgery and vitrectomy to various postoperative clinical parameters was studied. Clinical features at presentation included elevated intraocular pressure (IOP over 25 mmHg) in 52.4% of the eyes, uveitis in 69.6%, and corneal edema in 50.8%. Initial visual acuity was 20/400 or worse in 73.8% of the eyes. The mean preoperative visual acuity was 20/278 (median, 20/400), whereas the mean final visual acuity was 20/40 (median, 20/50) after a mean follow-up of 18.9 months. Retinal detachments were found in 20 eyes: 7 before vitrectomy and 13 during or after it. After surgery, 44% of eyes achieved a final visual acuity of 20/40 or better and 90% were 20/400 or better. The distribution of best-corrected final visual acuities among the eyes showed statistically significant differences based on the type of intraocular lens (IOL) used, with posterior chamber IOL greater than anterior chamber IOL, and anterior chamber IOL greater than aphakia. Reasons for a poor visual outcome included persistent corneal edema (four eyes), retinal detachment (two eyes), central retinal vein occlusion (two eyes), age-related macular degeneration (two eyes) glaucoma (one year), and endophthalmitis (one eye). CONCLUSIONS: There were no statistically significant differences between early (< 7 days) and delayed (8 days or more) vitrectomy when increased IOP, corneal edema, choroidal effusions, cystoid macular edema, and visual acuity were analyzed. The use of vitrectomy to remove posteriorly dislocated lens fragments has been shown to be an effective treatment method that significantly reduces the inflammatory response and hastens visual recovery.

Adult↗
PubMed1997

Using focus group methodology to develop breast cancer screening programs that recruit African American women.

Public communication campaigns are designed to increase the number of women who receive mammograms, breast examinations, and cervical exams. However, these campaigns have failed to recruit sufficient numbers of African American women. Focus group techniques were used to provide data to develop a communication campaign that would increase the knowledge, assess the attitudes, and change behaviors of African American women, aged 40-65, about the aforementioned preventive health practices. The discussions revealed that participants distrusted "clinics" and preferred being examined by "their own" or a private physician. Results further revealed that the personal influence of opinion leaders, combined with interpersonal contacts that encourage preventive care, help influence women to participate in mammography and cervical cancer screening.

Adult↗
PubMed1997

Macular hole surgery without using adjunctive additives.

BACKGROUND AND OBJECTIVE: To evaluate the efficacy of performing surgical techniques for macular holes without using adjunctive additives. PATIENTS AND METHODS: A prospective study was completed of consecutive eyes treated for macular holes of 1 year or less duration that had not had previous vitreous surgery. The best-corrected visual acuity and hole flattening were determined. RESULTS: Postoperative flattening of the hole was achieved in 39 (91%) of 43 eyes, with at least a 50% reduction of the minimum resolvable visual angle (3-line visual increase) in 65% of the eyes and a final vision of 20/40 or better in 40% of the eyes during the follow-up interval (mean 10.6 months). CONCLUSIONS: The success rate of current macular hole surgical techniques suggests that adjunctive additives may not be necessary for most cases. Thus, new treatment modalities need to be evaluated with carefully controlled studies.

Aged↗