Biomedical subjects

Scott D Smith

Publications and source records attributed to Scott D Smith.

At least 19 recordsLinked to original sources

PubMed2007

Comparison of silicone and polypropylene Ahmed Glaucoma Valve implants.

PURPOSE: To compare the efficacy and safety of silicone and polypropylene Ahmed Glaucoma Valves (AGVs) in patients with refractory glaucoma. METHODS: A retrospective chart review of 180 eyes of 166 patients who underwent AGV implantation with a minimum follow-up period of 3 months was performed. All patients who underwent implantation of either the AGV model S-2 (polypropylene) or model FP-7 (silicone) were included, unless previous laser cyclophotocoagulation had been performed. The primary outcome measures were the change in intraocular pressure (IOP) and visual acuity after surgery and the rate of postoperative complications. RESULTS: No significant differences were seen in the baseline characteristics of patients in each group. Baseline IOP was statistically equivalent in the 2 groups (silicone =33.8+/-11.9 mm Hg, polypropylene=33.0+/-10.3 mm Hg, P=0.6). A significant reduction in IOP from baseline was achieved after both silicone and polypropylene AGV implantation (silicone =-17.7+/-11.8 mm Hg, polypropylene =-17.7+/-11.3 mm Hg, both P<0.00005). However, there was no statistically significant difference in IOP decrease between the 2 groups at any follow-up visit (all P>0.09). The mean number of postoperative antiglaucoma medications was also similar in the silicone and the polypropylene AGV groups at each time point (all P>0.2). The rate of complications and the change in visual acuity did not differ between the 2 groups (P>0.6 and P>0.3, respectively). CONCLUSIONS: Silicone and polypropylene AGVs have similar results with respect to both safety and efficacy in the treatment of patients with refractory glaucoma.

Antihypertensive Agents↗

PubMed2006

Predictive factors for short-term visual outcome after intravitreal triamcinolone acetonide injection for diabetic macular oedema: an optical coherence tomography study.

AIM: To evaluate the predictive factors for visual outcome after intravitreal triamcinolone acetonide injection to treat refractory diabetic macular oedema (DME). METHODS: A retrospective chart review of patients with DME who met the following inclusion criteria was performed: clinically significant diabetic macular oedema, receipt of a 4 mg/0.1 ml intravitreal triamcinolone acetonide injection and an optical coherence tomography (OCT) of the macula performed up to 10 days before injection. All patients received a full ophthalmic examination including best-corrected Snellen visual acuity (VA). The main outcome measure was the mean change in vision 3 months after injection. RESULTS: Data from 73 eyes of 59 patients were analysed. After a mean follow-up of 324 days, the mean change in vision was -0.075 logarithm of minimum angle of resolution (logMAR) units, with 27.3% improving > or =3 lines, 6.8% declining > or =3 lines and 60.2% remaining stable within 1 line of baseline vision. Statistical analysis was performed using multivariate generalised estimating equations on the basis of data from 52 eyes of 42 patients. Factors associated with an improvement in vision 3 months after injection were worse baseline VA (-0.27 logMAR units/unit increase in baseline VA, p = 0.002) and presence of subretinal fluid (-0.17 logMAR units, p = 0.06). The presence of cystoid macular oedema negatively affected the visual outcome (0.15 logMAR units, p = 0.03). In addition, the presence of an epiretinal membrane (ERM) was associated with less visual improvement. ERM modified the effect of baseline VA as demonstrated by a significant interaction between these two variables (0.34 logMAR units/unit increase in baseline VA, p = 0.04). CONCLUSIONS: OCT factors and baseline VA can be useful in predicting the outcomes of VA 3 months after intravitreal triamcinolone acetonide injection in patients with refractory DME.

Aged↗

PubMed2006

Detection of primary angle closure using anterior segment optical coherence tomography in Asian eyes.

OBJECTIVE: To evaluate noncontact anterior segment optical coherence technology (AS-OCT) as a qualitative method of imaging the anterior chamber angle and to determine its ability to detect primary angle closure when compared with gonioscopy in Asian subjects. DESIGN: Prospective observational case series. PARTICIPANTS: Two hundred three subjects were recruited from glaucoma clinics in Singapore with diagnoses of primary angle closure, primary open-angle glaucoma, ocular hypertension, or cataract. Both eyes (if eligible) of each patient were included in the study. Exclusion criteria were pseudophakia or previous glaucoma surgery. METHODS: Images of the nasal, temporal, and inferior angles were obtained with AS-OCT in dark and then light conditions. Gonioscopic angle width was graded using the Spaeth classification for each quadrant in low lighting conditions. MAIN OUTCOME MEASURES: Angle closure was defined by AS-OCT as contact between the peripheral iris and angle wall anterior to the scleral spur and by gonioscopy as a Spaeth grade of 0 degree (posterior trabecular meshwork not visible). Comparison of the 2 methods in detecting angle closure was done by eye and by individual. Sensitivities and specificities of AS-OCT were calculated using gonioscopy as the reference standard. RESULTS: Complete data were available for 342 eyes of 200 patients. Of the patients, 70.9% had a clinical diagnosis of treated or untreated primary angle closure. Angle closure in > or =1 quadrants was detected by AS-OCT in 142 (71%) patients (228 [66.7%] eyes) and by gonioscopy in 99 (49.5%) patients (152 [44.4%] eyes). The inferior angle was closed more frequently than the nasal or temporal quadrants using both AS-OCT and gonioscopy. When performed under dark conditions, AS-OCT identified 98% of those subjects found to have angle closure on gonioscopy (95% confidence interval [CI], 92.2-99.6) and led to the characterization of 44.6% of those found to have open angles on gonioscopy to have angle closure as well. With gonioscopy as the reference standard, specificity of AS-OCT in the dark was 55.4% (95% CI, 45.2-65.2) for detecting individuals with angle closure. CONCLUSION: Anterior segment OCT is a rapid noncontact method of imaging angle structures. It is highly sensitive in detecting angle closure when compared with gonioscopy. More persons are found to have closed angles with AS-OCT than with gonioscopy.

Adult↗

PubMed2006

Imaging of trabeculectomy blebs using anterior segment optical coherence tomography.

OBJECTIVE: To image trabeculectomy blebs using anterior segment optical coherence tomography (AS-OCT). DESIGN: Prospective cross-sectional study. PARTICIPANTS: Fifty-five patients who had previously undergone trabeculectomy surgery. METHODS: All blebs were imaged with a prototype of the AS-OCT. Standardized color monophotographs of blebs were also obtained. Blebs were assessed for the following qualitative features: bleb height, thickness of the conjunctiva in the bleb wall, presence of cystic spaces within the bleb wall, apposition of the scleral flap to underlying sclera, and patency of the internal ostium. MAIN OUTCOME MEASURES: For blebs with preoperative intraocular pressure (IOP) > 18 mmHg with or without ocular hypotensive medication, success was defined as last recorded IOP< or =18 mmHg without topical glaucoma medication. For blebs with preoperative IOP< or =18 mmHg with ocular hypotensive medication, success was defined last recorded IOP< or =18 mmHg with cessation of ocular hypotensive medication. For blebs with preoperative IOP< or =18 mmHg without ocular hypotensive medication, a 20% drop in IOP with no ocular hypotensive medication was accepted as success. RESULTS: Seventy-eight blebs in eyes of 55 patients were imaged. There were 32 (58.2%) men and the mean age was 68.9+/-11.5 years. Fifty-seven (73.1%) blebs were classified as successful. Anterior segment optical coherence tomography identified the following bleb characteristics: total bleb height, bleb cavity, bleb wall thickness, tangential and radial dimensions, scleral flap thickness, and patency of the internal ostium. The majority of successful blebs displayed thickening of the bleb wall. Failed blebs were mostly low and were characterized by ostial occlusion, apposition of conjunctiva-episclera to sclera or apposition of the scleral flap to its bed. Thickening of the bleb wall was typically absent. CONCLUSIONS: AS-OCT is a promising tool to image trabeculectomy blebs. It was able to demonstrate features of bleb morphology not visible with the slit lamp.

Aged↗

PubMed2006

Proteomics of metal transport and metal-associated diseases.

Proteomics technology has the potential to identify groups of proteins that have similar biological function. However, few attempts have been made to identify and characterize metal-binding proteins by using proteomics strategies. Many transition metals are essential to sustain life. Copper, iron, and zinc are the most abundant transition metals relevant to biological systems. In addition to their important biological functions, metals can also catalyze the formation of damaging free radical species. Hence, their intracellular transport is tightly regulated. Despite recent insights into the intracellular transport of copper and other metals, our overall understanding of intracellular metal metabolism remains incomplete and it is likely that many metal-binding proteins remain undiscovered. Furthermore, the protein targets for metals during metal-associated disease states or during exposure to toxic levels of environmental metals are yet to be unravelled. A proteomics strategy for the analysis of metal-transporting or metal-binding proteins has the potential to uncover how a large number of proteins function in normal or metal-associated diseased states. Here we discuss the principal aspects of metal metabolism, and the recent developments in the area of the proteomics of metal transport.

Biological Transport↗

PubMed2006

Antiplatelet and anticoagulant therapy in patients with giant cell arteritis.

OBJECTIVE: Vision loss and cerebrovascular accidents often complicate giant cell arteritis (GCA). Antiplatelet and anticoagulant therapy reduce the risk of stroke in other populations. We sought to determine whether antiplatelet or anticoagulant therapy reduces ischemic complications in patients with GCA. METHODS: A retrospective chart review for patients with GCA was conducted. Included patients fulfilled modified 1990 American College of Rheumatology criteria for GCA. Collected information included demographic data, dates of antiplatelet or anticoagulant use, vision loss or stroke, and presence of bleeding complications and cerebrovascular risk factors. RESULTS: A total of 143 patients were included with a mean followup period of 4 years. The cohort included 109 women (76%) and 34 men (24%) with a mean age of 71.8 years. A total of 104 patients (73%) had a biopsy-proven diagnosis. Eighty-six patients (60.1%) had received long-term antiplatelet or anticoagulant therapy, including 18 (12.6%) who did not start therapy until after an ischemic event had occurred. Antiplatelet agents or anticoagulants were not used in 57 patients (39.9%). Overall, 11 of 68 patients (16.2%) had an ischemic event while receiving antiplatelet or anticoagulant therapy, compared with 36 of 75 patients (48.0%) not receiving such therapy (P < 0.0005). Univariate analysis failed to show a statistical difference between groups in regard to cerebrovascular risk factors, age, sex, or biopsy-proven diagnosis. Bleeding complications occurred in 2 patients receiving aspirin, 1 patient receiving warfarin, and 5 patients who did not receive anticoagulant or antiplatelet therapy. CONCLUSION: Antiplatelet or anticoagulant therapy may reduce the risk of ischemic events in patients with GCA. An increased risk of bleeding complications was not observed.

Aged↗

PubMed2006

Optical coherence tomographic patterns of diabetic macular edema.

PURPOSE: To describe various morphologic patterns of diabetic macular edema (DME) demonstrated by optical coherence tomography (OCT) and correlate them with visual acuity. DESIGN: Retrospective, observational, case series. METHODS: A retrospective review of all patients with DME who underwent OCT evaluation and met the study inclusion criteria between May 1998 and December 2002 at the Cole Eye Institute was performed. The OCT scans were evaluated for the presence of diffuse retinal thickening (DRT), cystoid macular edema (CME), posterior hyaloidal traction (PHT), serous retinal detachment (SRD), and traction retinal detachment (TRD). Additionally, the retinal thickness was measured and visual acuity evaluated. RESULTS: Two hundred seventy-six OCT scans of 164 eyes of 119 patients were identified. OCT revealed five morphologic patterns of DME: DRT (269, 97%), CME (152, 55%), SRD without PHT (19, 7.0%), PHT without TRD (35, 12.7%), and PHT with TRD (8, 2.9%). Mean retinal thickness varied depending on the morphologic pattern. The mean visual acuities (Snellen equivalent) also varied between groups. Increasing retinal thickness in all patterns was significantly correlated with worse visual acuity (P < .005). The OCT patterns containing CME (P = .01) and PHT without TRD (P = .02) were also significantly associated with worse vision. CONCLUSIONS: DME exhibits at least five different morphologic patterns on OCT. There is a significant correlation between retinal thickness and visual acuity.

Diabetic Retinopathy↗

PubMed2006

Antioxidants in prevention of cataracts in South India: methodology and baseline data*.

PURPOSE: To describe the methodology and baseline data for the Antioxidants in Prevention of Cataracts (APC) study in South India. METHODS: The APC study is a prospective, 5-year, randomized, triple-masked, placebo-controlled, field-based clinical trial to examine the effect of antioxidants (combination tablet of vitamins A, C, and E) on progression of cataract. The primary outcome variable is cataract progression (nuclear opalescence), evaluated with the slit-lamp biomicroscope by the Lens Opacification Classification System III method. Secondary outcome variables are progression in cortical and posterior subcapsular opacity and nuclear color, change in best corrected visual acuity, myopic shift, and treatment failure (progression to cataract surgery or best corrected vision worse than 20/400 in an eye). Inclusion criteria are age between 35 and 50 years and best-corrected visual acuity of 20/40 or better. Exclusion criteria are a diagnosis of diabetes mellitus or nonfasting blood glucose level>7.8 mmol/L, history or presence of various ocular conditions or treatment forms, or current use of vitamin supplements. Baseline ophthalmic, demographic, and potential cataract risk factor data (such as smoking, sunlight, or alcohol exposure) were compared between groups on an intent-to-treat basis. RESULTS: Of 954 people screened, 798 were enrolled, a sample size which exceeded the required estimate. More than 80% of subjects had 20/20 or better vision in at least one eye, and baseline prevalence of significant cataract according to the LOCS III grading scale was high. The two treatment groups were comparable for all baseline measures except alcohol intake. CONCLUSION: The sample size and group baseline characteristics will provide sufficient power to detect a change in cataract progression within 5 years.

Adult↗

PubMed2006