Search PubMed⌕ Search

Biomedical subjects

R Ritch

Publications and source records attributed to R Ritch.

At least 73 records · Page 4Linked to original sources
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

A uniform format for ocular imaging devices.

PURPOSE: To develop a uniform file format of ocular imaging data, including, but not limited to, ultrasound biomicroscopy, optical coherence tomography, and nerve fiber analyzer, capable of being transmitted via Internet or intranet for collaborative research and telemedicine use. METHOD: File filters were developed as dynamic link libraries (DLLs). These can read the original raw data format of each ocular imaging device. A data file format was also designed to describe these raw data uniformly in three different types of compression: noncompressed, run length compression, and differential pulse code modulation (DPCM). These three file formats were then tested in the following aspects: file size, speed of reading, and speed of writing. RESULTS: Run length compression failed to compress raw data, while DPCM compressed raw data successfully (< or =35.5%). The speed of reading and writing files was slowest in DPCM. However, the actual time of reading and writing was fast enough (<0.6 s) for daily work regardless of file compression methods. CONCLUSION: The format designed has robust potential to be the standard file format for transmission of any ocular imaging raw data.

Data Display↗
PubMed1999

Ginkgo biloba extract increases ocular blood flow velocity.

We evaluated a possible therapeutic effect of Ginkgo biloba extract (GBE) on glaucoma patients that may benefit from improvements in ocular blood flow. A Phase I cross-over trial of GBE with placebo control in 11 healthy volunteers (8 women, 3 men: Age; 34 +/- 3 years, mean +/- SE) was performed. Patients were treated with either GBE 40 mg or placebo three times daily orally, for 2 days. Color Doppler imaging (Siemens Quantum 2000) was used to measure ocular blood flow before and after treatment. There was a two week washout period between GBE and placebo treatment. Ginkgo biloba extract significantly increased end diastolic velocity (EDV) in the ophthalmic artery (OA) (baseline vs GBE-treatment; 6.5 +/- 0.5 vs 7.7 +/- 0.5 cm/sec, 23% change, p=0.023), with no change seen in placebo (baseline vs GBE-treatment; 7.2 +/- 0.6 vs 7.1 +/- 0.5 cm/sec, 3% change, p=0.892). No side effects related to GBE were found. Ginkgo biloba extract did not alter arterial blood pressure, heart rate, or IOP. Ginkgo biloba extract significantly increased EDV in the OA and deserves further investigation in ocular blood flow and neuroprotection for possible application to the treatment of glaucomatous optic neuropathy as well as other ischemic ocular diseases.

Adult↗
PubMed1999

Analysis of myocilin mutations in 1703 glaucoma patients from five different populations.

A glaucoma locus, GLC1A, was identified previously on chromosome 1q. A gene within this locus (encoding the protein myocilin) subsequently was shown to harbor mutations in 2-4% of primary open angle glaucoma patients. A total of 1703 patients was screened from five different populations representing three racial groups. There were 1284 patients from primarily Caucasian populations in Iowa (727), Australia (390) and Canada (167). A group of 312 African American patients was from New York City and 107 Asian patients from Japan. Overall, 61 different myocilin sequence variations were identified. Of the 61 variations, 21 were judged to be probable disease-causing mutations. The number of probands found to harbor such mutations in each population was: Iowa 31/727 (4.3%), African Americans from New York City 8/312 (2.6%), Japan 3/107 (2.8%), Canada 5/167 (3.0%), Australia 11/390 (2.8%) and overall 58/1703 (3. 4%). Overall, 16 (76%) of 21 mutations were found in only one population. The most common mutation observed, Gln368Stop, was found in 27/1703 (1.6%) glaucoma probands and was found at least once in all groups except the Japanese. Studies of genetic markers flanking the myocilin gene suggest that most cases of the Gln368Stop mutations are descended from a common founder. Although the specific mutations found in each of the five populations were different, the overall frequency of myocilin mutations was similar ( approximately 2-4%) in all populations, suggesting that the increased rate of glaucoma in African Americans is not due to a higher prevalence of myocilin mutations.

Asian People↗
PubMed1999

A slit-lamp needling filtration procedure for uncontrolled glaucoma in pseudophakic and aphakic eyes.

In one aphakic and one pseudophakic patient without previous filtration surgery, a transconjunctival needling procedure similar to that used for failed filtration procedures was performed to create a filtering bleb. In both cases, intraocular pressure was successfully lowered for 6 months until the occurrence of bleb encapsulation, which was relieved by transconjunctival needling. There were no complications. In selected cases, this minimally invasive slit-lamp needling procedure provides successful filtration.

Aged↗
PubMed1999

A slit-lamp eyepiece micrometer calibrated at 50-micron intervals.

Measurements of dimensions of various intraocular structures, both normal and abnormal, are both theoretically and clinically useful. The currently available standard Haag-Streit slit-lamp micrometer eyepiece is calibrated at 100 micron intervals. In order to achieve greater precision in measurement of smaller intraocular structures, the authors and Haag-Streit, Inc. (Kaniz, Switzerland) have developed an eyepiece calibrated in 50-micron intervals.

Calibration↗
PubMed1999

Effect of pupillary dilation on retinal nerve fiber layer thickness as measured by scanning laser polarimetry in eyes with and without cataract.

PURPOSE: This study was conducted to evaluate the effect of pupillary dilation on retinal nerve fiber layer (RNFL) thickness as measured by scanning laser polarimetry (SLP) in cataractous and noncataractous eyes. METHODS: The study included 31 eyes of 31 consecutive patients (mean age, 62.5 +/- 14.0 years; range, 30-76 years). Eyes with refractive error exceeding 5.0 D sphere or 2.0 D cylinder, nonlenticular media opacity, cup-to-disc ratio > 0.9, corneal disease, ocular inflammation, or previous intraocular surgery were excluded. A standard reticule was used to measure pupillary diameter. Cataract grade was evaluated by a single observer using the Lens Opacities Classification System (LOCS III). RNFL thickness measurements were obtained by means of SLP before and after pupillary dilation. RESULTS: Of the patients, 10 had clear lenses and 21 had variable degrees of lenticular opacification. In four eyes, imaging could not be performed because of dense cataracts. Mean pupillary diameters before and after dilation were 2.5 +/- 0.7 mm and 7.3 +/- 1.1 mm, respectively. There were no significant differences in global RNFL thickness before and after dilation in noncataractous and cataractous eyes. Among cataractous eyes in which imaging was possible, there was no correlation between difference in RNFL thickness before and after dilation and nuclear opalescence, nuclear color, and cortical and posterior subcapsular grading of the LOCS III score. Six of 27 eyes (22.2%) had a change of more than 10% in RNFL thickness after pupillary dilation. CONCLUSION: Although pharmacologic mydriasis does not statistically alter RNFL thickness as measured by SLP, approximately one fifth of such eyes will have a change of more than 10% in retardation. Uniformity in pupil size is recommended when longitudinally evaluating RNFL measurements.

Adult↗
PubMed1999

Latanoprost in glaucoma associated with Sturge-Weber syndrome: benefits and side-effects.

PURPOSE: This study was conducted to evaluate the ocular hypotensive efficacy, safety, and side effects of latanoprost 0.005% administered as adjunctive therapy in patients with Sturge-Weber syndrome (SWS) and glaucoma. METHODS: Commercially available latanoprost 0.005% was added as a single drop once daily to other antiglaucoma medications. Intraocular pressure (IOP) was measured at 1, 3, and 6 months of treatment. A successful response was defined as a reduction of at least 20% in IOP at the final follow-up evaluation without additional medical or surgical therapy and no adverse events related to latanoprost. RESULTS: 18 eyes of 18 patients with SWS and glaucoma were enrolled from 9 clinical centers. Mean baseline IOP was 28.4 +/- 7.1 mmHg (range, 17-42 mmHg). Using Kaplan-Meier analysis, a successful response to latanoprost was observed in 3 of 18 (16.7%) patients at the 6-month interval. Seven (38.9%) patients required surgery; three (16.7%) patients required additional medical therapy, seven (38.9%) patients had no change in therapy. One (5.6%) patient discontinued latanoprost treatment because of intolerable conjunctival hyperemia. Two successfully treated patients had significantly greater episcleral vessel engorgement after initiation of latanoprost therapy. CONCLUSION: Patients with SWS and glaucoma respond poorly to adjunctive latanoprost therapy and often require additional medical or surgical intervention. Increased episcleral vascular engorgement might result in greater operative risks should filtration surgery become necessary in these patients.

Adolescent↗
PubMed1999

Increasing sampling density improves reproducibility of optical coherence tomography measurements.

PURPOSE: Published series of peripapillary retinal nerve fiber layer (RNFL) measurements using optical coherence tomography (OCT) have sampled 100 evenly distributed points on a 360 degrees peripapillary circular scan. The goal of this study was to determine whether a four-fold increase in sampling density improves the reproducibility of OCT measurements. METHODS: Complete ophthalmic examinations, achromatic automated perimetry, and OCT imaging were performed in all patients. The OCT scanning consisted of three superior and inferior quadrantic scans (100 sampling points/quadrant) and three circular scans (25 points/quadrant). The RNFL thickness measurements and coefficient of variation (CV) were calculated for the superior and inferior quadrants for each sampling density technique. RESULTS: The study included 22 eyes of 22 patients (3 control subjects; 2 patients with ocular hypertension; and 17 patients with glaucoma). Quadrants with associated glaucomatous visual field loss on automated achromatic perimetry had thinner RNFLs than quadrants without functional defects for both the 25- and 100-points/quadrant scans. For quadrants associated with normal visual hemifields (n = 22), there was no difference between the 25- and 100-points/quadrant scans in mean RNFL thickness and CV. Among quadrants with visual field defects (n = 22), RNFL thickness measurements were thinner in the 25-points/quadrant scans than in the 100-points/quadrant scans. The CV for the 25-points/quadrant scans (25.9%) was significantly higher than that for the 100-points/quadrant scans (11.9%). CONCLUSION: Increasing the sampling density of OCT scans provides less variable representation of RNFL thickness. The optimal sampling density to achieve maximal reliability of OCT scans remains to be determined.

Adult↗
PubMed1999

Kinetic and static fixation methods in automated threshold perimetry.

PURPOSE: Static fixation is the standard method for stabilizing the eye during automated perimetry. Kinetic fixation is an alternative for fixation control in which the eye follows a moving target. This study was conducted to evaluate the fixation accuracy of static and kinetic fixation perimetry and to determine their ability to detect the absolute scotoma of the physiologic blind spot. METHODS: The 71 patients with early glaucomatous field loss (mean age 65 years) and 45 control subjects (mean age 57 years) recruited from five clinical sites underwent threshold testing on the Dicon perimeter (kinetic fixation; Vismed, San Diego, CA) and Humphrey Field Analyzer (static fixation). The frequency of Heijl-Krakau fixation catch-trial errors was used as an indicator of fixation accuracy, and the measured sensitivity at the physiologic blind spot was used as an indicator of perimetric accuracy. RESULTS: In patients with glaucoma, the frequency of fixation errors was significantly greater for kinetic fixation (17.2%) than for static fixation (10.2%). In the control group, the frequency of fixation errors also was significantly greater for kinetic fixation (27.5%) than for static fixation (12.6%). The threshold at the presumed location of the blind spot (15 degrees temporal, 3 degrees inferior from fixation) was 14.8 dB using kinetic fixation versus 4.0 dB with static fixation in patients with glaucoma, and 18.5 dB using kinetic fixation versus 2.5 dB using static fixation in the control group. CONCLUSION: Relative to static fixation, kinetic fixation was associated with fixation inaccuracy and underestimation of the absolute scotoma at the physiologic blind spot.

Adult↗
PubMed1999

Combined exfoliation and pigment dispersion: an overlap syndrome.

PURPOSE: To describe a series of patients with combined pigment dispersion syndrome (PDS) and exfoliation syndrome (XFS) and to introduce a concept, the overlap syndrome, to aid in assessing multiple risk factors for glaucomatous damage. METHODS: A retrospective review of the records of all patients on our database who carried a diagnosis of both PDS/pigmentary glaucoma (PG) and XFS/exfoliative glaucoma (XFG). RESULTS: We identified 26 patients as having both XFS/XFG and PDS/PG. The average age was 64.3 +/- 9.8 years and 19 of 26 were men. All patients had bilateral PDS/PG. Bilateral XFS/XFG was present in 9 of 26 patients, and of the 17 patients with unilateral involvement, the left eye was affected in 13. CONCLUSION: Both XFS and PDS are common. Middle-aged patients with known PDS/PG should be suspected of having the onset of XFS if 1 eye escapes intraocular pressure control. Patients presenting with unilateral XFG may also have signs of PDS/PG, often remitted. We define an overlap syndrome as the appearance of a new co-morbidity for glaucomatous damage in a patient with a pre-existing risk factor, which then changes the course, and prognosis of the disease. This concept should be particularly useful in dealing with secondary and normal-tension glaucoma.

Exfoliation Syndrome↗
PubMed1998

Anterior segment implantation cysts. Ultrasound biomicroscopy with histopathologic correlation.

OBJECTIVE: To correlate the clinical, histopathologic, and ultrasound biomicroscopic characteristics of anterior segment implantation cysts. METHODS: We performed a retrospective review of 7 cases of secondary anterior segment implantation cysts. We reviewed the clinical history, visual acuity, clinical findings, and ultrasound biomicroscopic characteristics in all cases. Histopathologic correlation was possible in 4 cases. RESULTS: Six eyes had been subjected to major trauma prior to cyst formation. Trauma was noted as blunt in 3 eyes and surgical in 3 eyes. The diagnosis was confirmed in 1 eye when conjunctival cells were aspirated on fine needle biopsy. Ultrasound biomicroscopy revealed large (mean +/- SD greatest diameter, 4.7 +/- 0.9 mm) cystic tumors. In 1 patient, a cyst-related indentation of the anterior lens surface was seen. Ultrasonographic evaluations of internal reflectivity revealed thick, moderately reflective cyst walls encapsulating a relatively hypoechoic core. In 3 cases, the cyst contents consisted of variably reflective material. The other 4 were completely sonolucent. Histopathologic correlation showed that the cyst walls were lined with stratified squamous epithelium. The moderately reflective cyst contents were found to be degenerated conjunctival cells with inflammatory foci and cholesterol crystals. The sonolucent regions correlated with inflammatory cells and fluid. CONCLUSIONS: This study demonstrates that implantation cysts are unilateral, large, and thick walled. They may be sonolucent or exhibit variable internal reflectivity. These findings as well as the extent of anterior segment involvement (particularly posterior extension) could be evaluated by ultrasound biomicroscopy prior to surgery.

Adolescent↗
PubMed1998

Late-onset bleb leaks after glaucoma filtering surgery.

OBJECTIVE: To determine the incidence of focal, late-onset, conjunctival bleb leaks after glaucoma filtering surgery. DESIGN: Prospective, cross-sectional analysis. SETTING: Tertiary care outpatient referral center. PATIENTS: Consecutive patients who underwent glaucoma filtering surgery prior to June 1996 presenting for evaluation from September 2,1996, through November 15,1996. Five hundred twenty-five eyes of 525 consecutive patients were enrolled in the study. INTERVENTION: Bleb height (elevated or flat), area (diffuse or localized), and wall thickness (thin, thick, or encapsulated) were classified. Each bleb was tested for focal leakage using a moistened fluorescein strip, cobalt blue illumination, and slit-lamp biomicroscopy. Diffuse transconjunctival aqueous flow did not qualify as a focal leak. MAIN OUTCOME MEASURE: Seidel-positive aqueous leakage. RESULTS: Bleb leakage occurred in 14 eyes following trabeculectomy (mitomycin C treatment, 10 eyes; 5-fluorouracil treatment, 3 eyes; no antifibrosis agent, 1 eye) and in 1 eye following combined cataract and glaucoma surgery with adjunctive mitomycin C therapy. Bleb leakage occurred more frequently in eyes that received mitomycin C (10 [3.7%] of 273 eyes) than 5-fluorouracil (3 [1.4%] of 213 eyes) or no antifibrosis agent (1 [2.6%] of 39 eyes), using Kaplan-Meier estimates (P=.008, log-rank test). Conjunctival blebs were significantly thinner after trabeculectomy with mitomycin C than with 5-fluorouracil (P=.001). Bleb wall thickness was greater following combined cataract and glaucoma surgery than following trabeculectomy alone (P=.008). Age (P=.84), sex (P=.68), race (P=.77), duration of mitomycin C exposure (P=.62), number of antiglaucoma medications (P=.16), and total 5-fluorouracil dose (P=.85) were not associated with late-onset leaks. CONCLUSIONS: The risk of late-onset focal bleb leakage increases following trabeculectomy with mitomycin C therapy. Late leakage after combined cataract and glaucoma surgery is infrequent.

Adolescent↗
PubMed1998

Angle-closure glaucoma associated with occult annular ciliary body detachment.

OBJECTIVE: To evaluate the role of annular ciliary body detachment in the development of postoperative angle-closure glaucoma. DESIGN: Case series. SETTING: Tertiary care glaucoma referral center. METHODS: High-resolution, anterior segment ultrasound biomicroscopy, ophthalmoscopy, and B-scan ultrasonography were performed on 6 eyes of 6 patients with a clinical diagnosis of postoperative malignant glaucoma. RESULTS: Each eye had an elevated intraocular pressure, a shallow anterior chamber, 1 or more patent iridectomies, and no ophthalmoscopic or B-scan ultrasound evidence of serous or hemorrhagic ciliochoroidal detachment. Ultrasound biomicroscopy revealed annular ciliary body detachment in each eye. In 4 eyes, observation with topical medical treatment was associated with deepening of the anterior chamber, reduced intraocular pressure, and resolution of the detachment. Drainage of the supraciliary fluid was performed in 2 eyes. CONCLUSION: Occult, annular, serous detachment of the ciliary body may cause postoperative angle-closure glaucoma. This entity is clinically indistinguishable from malignant glaucoma. Ultrasound biomicroscopy facilitates the diagnosis.

Aged↗
PubMed1998

The Glaucoma Symptom Scale. A brief index of glaucoma-specific symptoms.

OBJECTIVE: To develop a brief symptom survey specific for persons with glaucoma, the Glaucoma Symptom Scale (GSS). DESIGN: Cross-sectional study of symptoms, functional impairment, and vision-targeted health-related quality of life among persons with glaucoma. PATIENTS: A sample of 147 persons with glaucoma among a broad range of treatment categories from 4 tertiary care glaucoma centers and 44 persons without eye disease enrolled from the same 4 centers. MAIN OUTCOME MEASURES: Participants completed a modified version of the Ocular Hypertension Treatment Study 10-item symptom checklist. Participants also completed 2 vision-specific measures, the National Eye Institute Visual Function Questionnaire and the VF-14. Participants underwent a clinical evaluation, including ocular and medical history, dilated ophthalmic examination, and Humphrey 24-2 automated visual field testing. RESULTS: The GSS has 2 underlying domains that demonstrate sufficient internal consistency reliability for between-group comparisons. The GSS discriminates well between persons with and without glaucoma. Additionally, tests of association with clinical markers of glaucoma severity support the clinical validity of the measure and tests of association with established vision-targeted measures provide evidence of construct validity. CONCLUSION: The simplicity, brevity, and psychometric properties of the GSS support its use in clinical practice and research to quantify symptoms in patients with glaucoma and to assist in investigations concerning the effect of glaucoma and treatments.

Cross-Sectional Studies↗