Search PubMed⌕ Search

Biomedical subjects

D S Greenfield

Publications and source records attributed to D S Greenfield.

At least 19 recordsLinked to original sources
PubMed2006

An enhancement module to improve the atypical birefringence pattern using scanning laser polarimetry with variable corneal compensation.

AIM: To examine the repeatability and effect of an enhancement module on the severity of atypical birefringence patterns (ABP) using scanning laser polarimetery (SLP) with variable corneal compensation (VCC). METHODS: 16 patients with perimetric glaucoma (PG), 24 glaucoma suspect and pre-perimetric glaucoma (GSPPG), and 12 normal volunteers (N) were included. One randomly selected eye of each volunteer was scanned three times using VCC and enhanced corneal compensation (ECC) at the same session by the same examiner. Typical scan scores (TSS) were calculated to evaluate the ABP. Coefficients of variability (CoV), coefficients of repeatability (CoR), and intraclass correlation coefficients (ICC) were calculated. RESULTS: The mean TSS using ECC (n = 97.3 (5.5), GSPPG = 98.3 (3.5), PG = 99.2 (2.3)) was significantly higher (p = 0.02, 0.01, and 0.006, respectively) compared with VCC (86.5 (14.4), 88.2 (18.2), and 83.4 (2.2), respectively). VCC parameters had a CoR of 1.2-6.5, CoV of 1.9%-8.6%, and ICC of 0.8-0.9. ECC parameters had a CoR of 0.5-4.0, CoV of 0.3%-5.1%, and ICC of 0.2-0.9. TSNIT average was the overall best performing parameter with the highest repeatability and least variability using both techniques (CoR<2.1, CoV<2%). CONCLUSION: The enhancement module significantly reduced the severity of ABP and maintained a high level of repeatability of retardation measurements.

Adult↗
PubMed2001

Presumed topiramate-induced bilateral acute angle-closure glaucoma.

PURPOSE: We describe a case of bilateral angle-closure glaucoma associated with oral topiramate therapy. METHODS: Interventional case report. Case report with echographic illustration. RESULTS: A 51-year-old man developed bilateral acute angle-closure glaucoma 2 weeks after beginning topiramate therapy for bipolar affective disorder. Laser peripheral iridotomy was performed in the right eye without resolution of the acute attack. Echography revealed lens thickening and ciliochoroidal detachments in both eyes. Visual acuity, intraocular pressure, and anterior and posterior segment anatomy normalized 2 weeks after cessation of topiramate therapy. CONCLUSION: Topiramate, a new sulfa-derivative antiepileptic medication, may cause idiosyncratic ciliochoroidal detachments and ciliary body edema leading to anterior displacement of the lens-iris diaphragm, lens thickening, and acute angle-closure glaucoma.

Acute Disease↗
PubMed2001

Intermediate-term outcomes of 350-mm(2) Baerveldt glaucoma implants.

OBJECTIVE: To determine the intermediate-term outcome of 350-mm(2) Baerveldt glaucoma implants. DESIGN: Retrospective, noncomparative case series. PARTICIPANTS: Sixty-five patients (65 eyes). INTERVENTION: Implantation of 350-mm(2) Baerveldt glaucoma drainage device. MAIN OUTCOME MEASURES: Intraocular pressure, number of glaucoma medications, best-corrected Snellen visual acuity, length of follow-up, risk factors for failure, and complications. RESULTS: Mean intraocular pressure was reduced from a preoperative value of 32 mmHg to a 2-year postoperative value of 14 mmHg (56% reduction, P < 0.001). Success rates at 2-year follow-up were 71%, 81%, 78%, 60%, and 47% for the overall group, primary open-angle glaucoma group, neovascular group, uveitic group, and other group, respectively. After accounting for the effect of diagnosis group, significant risk factors in the overall group for failure at 2 years included younger age, high preoperative intraocular pressure, and more prior incisional surgeries. Glaucoma medication use in our overall study population was reduced from 2.5 mean preoperative medications to 0.8 postoperative medications (68%). Median change in Snellen visual acuity between preoperative and 2-year postoperative visits was not significant in the overall group. Postoperative complications included choroidal effusion in 15 patients (23%), tube obstruction by blood or vitreous in five patients (8%), phthisis in four patients (6%), aqueous misdirection in two patients (3%), strabismus in two patients (3%), tube-cornea touch in two patients (3%), endophthalmitis in two patients (3%), and retinal detachment in two patients (3%). No patients had suprachoroidal hemorrhage. CONCLUSIONS: The 350-mm(2) Baerveldt glaucoma implants are a safe and effective treatment for intermediate-term intraocular pressure control in patients with refractory glaucoma.

Adult↗
PubMed2001

Stability of corneal polarization axis measurements for scanning laser polarimetry.

OBJECTIVE: Corneal polarization axis (CPA) has been reported to affect retardation measurements obtained with scanning laser polarimetry. The purpose of this investigation was to evaluate the longitudinal stability of CPA measurements. DESIGN: Prospective, noncomparative case series. PARTICIPANTS: Persons with normal corneas were enrolled; eyes with less than 1 year of follow-up from the initial CPA measurement were excluded. INTERVENTION: We constructed a noninvasive slit-lamp-mounted device incorporating two crossed linear polarizers and an optical retarder to measure the slow axis of corneal birefringence, or CPA. MAIN OUTCOME MEASURES: Corneal polarization axis measurements. RESULTS: Seventy-one eyes of 40 individuals (23 female, 17 male) were enrolled in this investigation (mean age, 42.9 +/- 13.6 years; range, 22-85 years). Initial CPA measurements (mean, 24.0 +/- 18.0 degrees nasally downward; range, 67 degrees downward to 13 degrees nasally upward) were strongly associated (R2 = 0.88; P < 0.0001) with repeat CPA measurements (mean, 20.9 +/- 14.6 degrees nasally downward; range, 59 degrees nasally downward to 14 degrees nasally upward). The mean change in CPA was 4.1 +/- 3.2 degrees (range, 0-13 degrees ). Corneal polarization axis stability was statistically associated with the mean (initial and repeat) CPA (R2 = 0.1; P = 0.009), but not associated with age (R2 = 0.0003; P = 0.9) or gender (R2 = 0.03; P = 0.2). CONCLUSIONS: Corneal polarization axis measurements have good 1-year stability. These data suggest that CPA should not contribute significantly to longitudinal measurements of retinal nerve fiber layer thickness obtained with scanning laser polarimetry.

Adult↗
PubMed2001

Late endophthalmitis associated with glaucoma drainage implants.

OBJECTIVE: To report the clinical course of a series of patients who had late endophthalmitis develop after glaucoma drainage implant (GDI) surgery. DESIGN: Noncomparative, interventional, consecutive case series. PARTICIPANTS: Four patients were identified with late endophthalmitis associated with Baerveldt glaucoma implants. METHODS: The medical records of all patients with endophthalmitis associated with a GDI treated at the Bascom Palmer Eye Institute or University of Florida between January 1, 1987 and December 31, 1999 were retrospectively reviewed. Patients with culture-positive endophthalmitis diagnosed more than 1 month after GDI surgery were included in this series. MAIN OUTCOME MEASURES: Visual acuity and intraocular pressure (IOP). RESULTS: Late endophthalmitis associated with Baerveldt glaucoma implants developed 7 weeks to 2 years postoperatively. Exposure of the GDI tube was present in all cases. The implant was removed in three of four patients. Visual acuity worsened from preinfection level in two of four cases. IOP was controlled at last follow-up in all patients, although replacement of the explanted GDI was required in one patient. CONCLUSIONS: Late endophthalmitis may occur after GDI surgery. Exposure of the GDI tube seems to represent a major risk factor for these infections. To prevent this potentially devastating complication, we recommend prophylactic surgical revision with a patch graft in all cases in which there is an exposed GDI tube.

Aged↗
PubMed2000

Baerveldt drainage implants in eyes with a preexisting scleral buckle.

OBJECTIVE: To describe the surgical insertion of a Baerveldt drainage implant and postoperative visual acuity and intraocular pressure (IOP) outcomes in patients with a preexisting scleral buckle. METHODS: Medical records of all patients with a preexisting scleral buckle who underwent insertion of a Baerveldt drainage implant at Bascom Palmer Eye Institute, Miami, Fla, from January 1, 1994, through December 31, 1998, were reviewed. Outcome measures included visual acuity and IOP at 1 year. RESULTS: At 1 year postoperatively, 14 (88%) of 16 patients had stable or improved visual acuity. Preoperatively, mean IOP was 30.9 mm Hg and the mean number of antiglaucoma medications was 3.4; at 1 year postoperatively, mean IOP was 12.0 mm Hg and the mean number of antiglaucoma medications was 0.8 (P<.001). Nine patients (56%) achieved an IOP of greater than 5 and no greater than 21 mm Hg without medication, and an additional 7 (44%) achieved this level of IOP control with medication. No patient required further surgery for uncontrolled IOP during the follow-up interval, which ranged from 19. 1 to 45.5 months. CONCLUSION: Baerveldt drainage device insertion behind or over a preexisting encircling band is often successful in managing refractory glaucoma in patients who have undergone previous scleral buckling procedures. Arch Ophthalmol. 2000;118:1509-1513

Adolescent↗
PubMed2000

Risk factors for glaucoma filtering bleb infections.

OBJECTIVE: To determine risk factors for bleb-related ocular infection after glaucoma filtering surgery. METHODS: A case-control study comparing all consecutive cases of glaucoma filtering bleb-related infections (55 eyes of 55 patients) with matched control eyes between January 1, 1990, and June 30, 1998, was performed. Bleb-related infection was classified as blebitis when a mucopurulent infiltrate was identified within the bleb and associated with mild to moderate anterior segment inflammation. Eyes with endophthalmitis had hypopyon, cells in the anterior vitreous cavity, or a positive vitreous biopsy sampling result. A control was selected for each case based on matching of the surgeon, date and type of glaucoma surgery, and type of antifibrotic agent used. Multivariate, matched, case-control logistic regression analysis was performed using age, race, sex, diagnosis, number of previous incisional operations, filtering bleb location, and presence of bleb leak to determine which variables were associated with bleb-related infection. RESULTS: The odds of an eye with a bleb-related infection being seen with a concomitant late-onset bleb leak are 25.8 times the odds of a noninfected eye having a late-onset bleb leak at any time in the postoperative period (P<.001; 95% confidence interval, 2.3-294.1). Other risk factors for bleb-related infection included younger age (P = .05), black race (P = .03), diagnosis of primary open-angle glaucoma (P = .03), and inferior location of the filtering bleb (P = .04). CONCLUSIONS: Late-onset bleb leakage is a significant risk factor for bleb-related infection. The risk of infection may warrant closure of late-onset bleb leaks in selected eyes.

Aged↗
PubMed2000

Effect of corneal polarization axis on assessment of retinal nerve fiber layer thickness by scanning laser polarimetry.

PURPOSE: Scanning laser polarimetry uses an anterior segment compensating device that assumes a fixed axis of corneal birefringence, which we call the corneal polarization axis. The purpose of this investigation was to establish the distribution of corneal polarization axes among a population of normal eyes and to evaluate the relationship between corneal polarization axis and posterior segment retardation. METHODS: We constructed a noninvasive slit lamp-mounted device incorporating two crossed linear polarizers and an optical retarder in order to measure the slow axis of corneal birefringence. Normal subjects underwent corneal polarization axis measurement. A subset of eyes underwent scanning laser polarimetry of the peripapillary retinal nerve fiber layer (n = 32) and macula (n = 29), and retardation measurements were evaluated in each group. RESULTS: One hundred eighteen eyes of 63 normal subjects (35 female, 28 male) underwent corneal polarization axis measurement (mean age, 45.5 +/- 17.1 years). Six eyes (5.1%) demonstrated unmeasurable corneal polarization. In the remaining 112 eyes, the mode of the corneal polarization axis distribution was 10 to 20 degrees nasally downward (range, 90 degrees nasally downward to 54 degrees nasally upward). A significant (P <.0001) correlation was observed between fellow eyes (R(2) =.52), with a mean difference of 11.2 +/- 10.5 degrees (range, 0-52 degrees). Corneal polarization axis was significantly associated (R(2) =.52-.84) with retinal nerve fiber layer and macula summary retardation parameters (average thickness, ellipse average, superior and inferior average, superior and total integral; P <.0001 for all groups). CONCLUSIONS: The mean corneal polarization axis among normal corneas is nasally downward; however, considerable intraindividual and interindividual variability exists. The linear relationship between corneal polarization axis and posterior segment retardation parameters is responsible, in part, for the wide distribution of retinal nerve fiber layer thickness data generated by scanning laser polarimetry.

Adult↗
PubMed2000

Optical coherence tomography and scanning laser polarimetry in normal, ocular hypertensive, and glaucomatous eyes.

PURPOSE: To evaluate the relationship between visual function and retinal nerve fiber layer measurements obtained with scanning laser polarimetry and optical coherence tomography in a masked, prospective trial. METHODS: Consecutive normal, ocular hypertensive, and glaucomatous subjects who met inclusion and exclusion criteria were evaluated. Complete ophthalmologic examination, disk photography, scanning laser polarimetry, optical coherence tomography, and automated achromatic perimetry were performed. RESULTS: Seventy-eight eyes of 78 patients (17 normal, 23 ocular hypertensive, and 38 glaucomatous) were enrolled (mean age, 56.8+/-11.5 years; range, 26 to 75 years). Eyes with glaucoma had significantly greater neural network scores on scanning laser polarimetry and lower maximum modulation, ellipse modulation, and mean retinal nerve fiber layer thickness measured with optical coherence tomography compared with normal and ocular hypertensive eyes, respectively (all P<.005). Significant associations were observed between neural network number (r = -.51, r = .03), maximum modulation (r = .39, r = -.32), ellipse modulation (r = .36, r = -.28), and optical coherence tomography-generated retinal nerve fiber layer thickness (r = .68, r = -.59) and visual field mean deviation and corrected pattern standard deviation, respectively. All scanning laser polarimetry parameters were significantly associated with optical coherence tomography-generated retinal nerve fiber layer thickness. CONCLUSION: Optical coherence tomography and scanning laser polarimetry were capable of differentiating glaucomatous from nonglaucomatous populations in this cohort; however considerable measurement overlap was observed among normal, ocular hypertensive, and glaucomatous eyes. Retinal nerve fiber layer structural measurements demonstrated good correlation with visual function, and retinal nerve fiber layer thickness by optical coherence tomography correlated with retardation measurements by scanning laser polarimetry.

Adult↗
PubMed2000

Trabeculectomy with intraoperative mitomycin C versus 5-fluorouracil. Prospective randomized clinical trial.

OBJECTIVE: To evaluate the relative efficacy and safety of 5-fluorouracil (5-FU) and mitomycin C (MMC) when used as adjuncts with primary trabeculectomy in eyes not at high risk for failure. DESIGN: Prospective multicenter, randomized clinical trial. PARTICIPANTS: One hundred thirteen patients with primary open-angle, pseudoexfoliative, pigmentary, or angle-closure glaucoma undergoing primary trabeculectomy were recruited. METHODS: One eye of each patient was randomized to receive either 5-FU (50 mg/ml for 5 minutes) or MMC (0.4 mg/ml for 2 minutes). MAIN OUTCOME MEASURES: Intraocular pressure (IOP), visual acuity, complications, and interventions were documented at fixed intervals after surgery. The study also examined progression of visual field loss, long-term complications, and bleb appearance 3 years after surgery. RESULTS: Of the 108 patients with complete perioperative information, 54 eyes received 5-FU and 54 received MMC. The proportion of patients reaching different predefined target IOPs after surgery was slightly higher in the MMC group than in the 5-FU group. This difference was less than 25%, which would have been necessary to achieve statistical significance with a power of 0.8 and the sample size used. Likewise, there was no statistically significant difference between the groups with regard to mean preoperative IOP, complications, or interventions. Mean postoperative follow-up was 309 and 330 days in the 5-FU and MMC groups, respectively (P = 0.593). CONCLUSIONS: 5-Fluorouracil and MMC were found to be equally safe and effective adjuncts to primary trabeculectomy in the short- and medium-term postoperative periods.

Aged↗
PubMed1999

Iridolenticular contact decreases following laser iridotomy for pigment dispersion syndrome.

OBJECTIVE: To evaluate changes in anterior segment anatomy after laser iridotomy for pigment dispersion syndrome. METHODS: Ultrasound biomicroscopy was performed on 7 eyes of 7 untreated patients with reverse pupillary block and pigment dispersion syndrome. A radially oriented image with the probe perpendicular to the eye in the superior meridian was obtained before and at least 1 week after laser iridotomy in each eye. We assessed changes in angle recess area and iris-lens contact distance. RESULTS: Mean +/- SD patient age was 31.3 +/- 5.7 years and mean +/- SD refractive error was -5.0 +/- 3.9 diopters. Angle recess area (mean +/- SD, 0.78 +/- 0.28 vs 0.35 +/- 0.11 mm2; P=.001, paired t test) and iris-lens contact distance (2.05 +/- 0.28 vs 0.79 +/- 0.13 mm; P<.001) decreased following iridotomy. Central anterior chamber depth did not change. CONCLUSION: Flattening of the iris following laser iridotomy for pigment dispersion syndrome causes a decrease in iris-lens contact and angle width while lens position remains constant.

Adult↗
PubMed1999

Hyphema associated with pupillary dilation in a patient with exfoliation glaucoma and warfarin therapy.

PURPOSE: To describe an unusual hemorrhagic complication associated with pupillary dilation in a patient with exfoliation glaucoma taking anticoagulation therapy. METHODS: A 78-year-old woman with bilateral exfoliation glaucoma who was receiving warfarin, 2 mg daily, for systemic anticoagulation developed acute visual loss in the right eye several hours after pupillary dilation. RESULT: Examination disclosed bilateral advanced exfoliation glaucoma, localized vascularized iridolenticular adhesions in the right eye, and a 4-mm layered hyphema in the right eye. CONCLUSION: Patients with exfoliation glaucoma and vascularized posterior synechiae who are receiving anticoagulation therapy are at increased risk for visually significant spontaneous hyphema after pupillary dilation.

Aged↗
PubMed1999

Aqueous misdirection after glaucoma drainage device implantation.

OBJECTIVE: To describe the clinical presentation, outcome, and possible underlying mechanism of aqueous misdirection after glaucoma drainage device implantation. DESIGN: Retrospective, noncomparative, interventional case series. PARTICIPANTS: Ten eyes (five primary open-angle glaucoma, four chronic angle-closure glaucoma, one nanophthalmos) of nine patients with a mean age of 68.5+/-12.0 years (range, 43-83 years). INTERVENTION: The authors reviewed the medical records of all patients with a clinical diagnosis of aqueous misdirection after Baerveldt glaucoma drainage device implantation at two tertiary care referral centers from October 1992 to October 1997. Surgery was performed in a standardized fashion; all drainage tubes were inserted in the anterior chamber and occluded with an external 7-0 polyglactin ligature. All eyes were treated with topical corticosteroids, cycloplegia, and aqueous suppressants. Eyes with persistent aqueous misdirection received neodymium:YAG (Nd:YAG) hyaloidotomy or pars plana vitrectomy. MAIN OUTCOME MEASURES: Visual acuity, intraocular pressure, biomicroscopic anterior chamber depth, and antiglaucomatous medication. RESULTS: All eyes had axial shallowing of the anterior chamber, one or more patent iridotomies, and no ophthalmoscopic or B-scan ultrasonographic evidence of serous or hemorrhagic ciliochoroidal detachment. Median time to the development of angle-closure glaucoma was 33.5 days (range, 1-343 days) and mean intraocular pressure at diagnosis was 27.7+/-18.7 mm Hg (range, 10-62 mm Hg). Normalization of anterior segment anatomy was achieved with aqueous suppression and cycloplegia (one eye); Nd:YAG capsulotomy (four eyes); pars plana vitrectomy alone (two eyes) or with lensectomy (one eye), and pars plana vitrectomy with intraocular lens explanation (two eyes). Mean final intraocular pressure was 14.1+/-6.0 mmHg at a mean follow-up of 9.1+/-7.8 months after the development of aqueous misdirection (range, 1-23 months). CONCLUSIONS: Aqueous misdirection may develop days to months after glaucoma drainage device implantation. In this series, there was a poor response to medical therapy, and normalization in anterior chamber depth required aggressive laser and surgical therapy.

Adult↗
PubMed1999

Heidelberg retina tomography and optical coherence tomography in normal, ocular-hypertensive, and glaucomatous eyes.

PURPOSE: To evaluate optic disc and retinal nerve fiber layer (RNFL) appearance in normal, ocular-hypertensive, and glaucomatous eyes undergoing confocal scanning laser ophthalmoscopy and optical coherence tomography (OCT). DESIGN: Prospective, cross-sectional study. PARTICIPANTS: Seventy-eight eyes of 78 consecutive normal (n = 17), ocular-hypertensive (n = 23), and glaucomatous subjects (n = 38) were enrolled. METHODS: Each patient underwent complete ophthalmic examination, achromatic automated perimetry, confocal scanning laser ophthalmoscopy (Heidelberg Retinal Tomography [HRT]), and OCT. Topographic HRT parameters (disc area, cup-disc ratio, rim area, rim volume, cup shape measure, mean RNFL thickness, and cross-sectional area) and mean OCT-generated RNFL thickness were evaluated in each group. MAIN OUTCOME MEASURES: OCT and HRT assessment of optic disc and RNFL anatomy. RESULTS: OCT RNFL thickness showed no difference between normal and ocular-hypertensive eyes (P = 0.15) but was significantly less in glaucomatous eyes (P < 0.001). HRT measurements of rim area, cup-disc ratio, cup shape measure, RNFL thickness, and RNFL cross-sectional area were significantly less in glaucomatous eyes (all P < 0.005) and were correlated with mean OCT RNFL thickness (all P < 0.02). RNFL thickness using OCT or HRT was highly correlated with visual field mean defect during achromatic perimetry (P < 0.0001). CONCLUSION: Both HRT and OCT can differentiate glaucomatous from nonglaucomatous eyes. RNFL thickness measurements using OCT correspond to disc topographic parameters using HRT.

Adult↗
PubMed1999

Differential diagnosis of anterior segment cysts by ultrasound biomicroscopy.

BACKGROUND: To describe the ultrasound biomicroscopic (UBM) features of anterior segment cysts. DESIGN: A retrospective case series. PARTICIPANTS: One hundred eighteen eyes with anterior segment cysts examined by UBM at The New York Eye and Ear Infirmary between August 1992 and November 1997 were included in this study. INTERVENTION: The authors reviewed demographic and diagnostic data from the medical record including ocular and medical history, age, race, gender, and intraocular pressure. Ultrasound data concerning the type, number, position, and acoustic characteristics of cysts were recorded. The authors then correlated the written, clinical, and UBM characteristics. RESULTS: One hundred eyes (92.6%) had neuroepithelial cysts. Ninety (83.3%) of these had primary neuroepithelial cysts, 10 (9.3%) had cysts associated with uveitis, 7 (6.5%) had implantation cysts, and 1 (0.9%) had a cavitated ciliary body tumor. Neuroepithelial cysts typically were round or ovoid, thin-walled, and echolucent. Of the 90 eyes with primary neuroepithelial cysts, 56 (62.2%) had 3 or fewer cysts; multiple cysts (>3 per eye) were found in 34 eyes (37.8%). The multiple cysts occupied more than 180 degrees in 12 patients (13.3%). Primary neuroepithelial cysts were located at the iridociliary junction (74.2%), pars plicata (14.0%), pars plana (6.8%), and iris (5.0%). Implantation cysts (seven eyes) tended to have thicker walls and two contained a copious, echogenic material. CONCLUSION: The UBM results provide important information regarding location and extent of anterior segment cystic lesions. Ultrasound characteristics may help differentiate between neuroepithelial, implantation, and neoplastic cysts.

Adolescent↗
PubMed1999

Glaucomatous versus nonglaucomatous optic disc cupping: clinical differentiation.

Cupping of the optic nerve head associated with normal intraocular pressure (IOP) is a common clinical presentation for which clearly defined management guidelines have not been established. The clinical approach represents a diagnostic challenge because the mechanism of optic nerve injury is often difficult to objectively establish. Of paramount importance is the primary distinction between physiologic cupping and pathologic cupping, and the accurate subclassification of eyes with pathologic cupping. Therefore, it is essential for clinicians to differentiate glaucomatous from nonglaucomatous disc damage. This article reviews the clinical differentiation of eyes with glaucomatous and nonglaucomatous optic disc cupping.

Chronic Disease↗