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Biomedical subjects

R Ritch

Publications and source records attributed to R Ritch.

At least 55 records · Page 3Linked to original sources
PubMed2000

Combined exfoliation and pigment dispersion: paradigm of an overlap syndrome.

OBJECTIVE: 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. DESIGN: Clinic-based, cross-sectional study. SETTING: New York Eye and Ear Infirmary. PARTICIPANTS: Twenty-six patients identified from the glaucoma database as having combined pigment dispersion syndrome-glaucoma and exfoliation syndrome-glaucoma. MAIN OUTCOME MEASURES: Quantification of patients with both pigment dispersion syndrome-glaucoma (PDS/PG) and exfoliation syndrome-glaucoma (XFS/XFG) and its clinical implications. RESULTS: Among the 26 patients (all white) 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. CONCLUSIONS: Both XFS and PDS are common. Middle-aged patients with known PDS/PG should be suspected of having the onset of XFS if one eye escapes intraocular pressure control. Patients with unilateral XFG at presentation may also have signs of PDS/PG, often remitted. We define the term overlap syndrome to describe the sequential appearance over time of two or more risk factors for glaucomatous damage. The appearance of a new risk factor in a patient whose condition has been stable can alter the course and prognosis of the disease. This concept should prove useful in dealing with secondary and normal-tension glaucomas.

Aged↗
PubMed2000

Low-dose 5-fluorouracil trabeculectomy as initial surgery in uncomplicated glaucoma: long-term followup.

OBJECTIVE: To compare the effectiveness of trabeculectomy with adjunctive, low-dose, subconjunctival 5-fluorouracil (5-FU) to trabeculectomy alone in patients with uncomplicated glaucoma undergoing their first incisional surgical procedure. DESIGN: Retrospective, nonrandomized comparative trial. PARTICIPANTS: Consecutive series of 52 patients and 74 control subjects. INTERVENTION: Trabeculectomy was performed in all patients. Study patients received adjunctive, subconjunctival injections of 5-FU up to 14 days from the date of surgery. MAIN OUTCOME MEASURES: Intraocular pressure, number of postoperative antiglaucoma medications, interventions, and complications were evaluated. RESULTS: Mean followup for all patients was 58.1 +/- 44.1 months (range, 1.1-159.9 months). Mean followup for successful eyes was 55.9 +/- 47.1 months (range, 7.6-159.9 months). The cumulative 5-year success (intraocular pressure [IOP] < or = 21 mmHg) was 77.8% in the 5-FU group and 62.2% in the control group (P = 0.02, Wilcoxon test. Complete success (IOP < or = 21 mmHg without medications) at 5 years was lower in both the 5-FU group (72.3%) and the control group (51.3%). Postoperative mean IOP at 5 years for all successful patients was lower in eyes receiving 5-FU (10.7 +/- 3.6 mmHg vs. 16.0 +/- 6.1 mmHg [P = 0.02, t-test]). For those patients considered to be complete successes, there was no difference in IOP between the two groups of patients at any evaluated time interval. Patients in the 5-FU group were using 0.7 +/- 1.1 medications at final followup compared with 1.8 +/- 1.4 medications in the control group (P = < 0.0001, t test). Bleb-related ocular infection occurred in 6.3% of patients and was more common in patients receiving 5-FU than controls (6 of 52 vs 2 of 74, respectively; P = 0.05, Fischer's exact test). CONCLUSIONS: Adjunctive, low-dose 5-FU at the time of initial surgery in uncomplicated glaucoma improves long-term IOP control and reduces the need for postoperative, antiglaucoma therapy. Eyes receiving 5-FU are at greater risk of developing late bleb-related ocular infection.

Adolescent↗
PubMed2000

Trabeculectomy with mitomycin-C in the treatment of pediatric glaucomas.

PURPOSE: To evaluate the effectiveness and safety of trabeculectomy with mitomycin-C (MMC) in the management of childhood glaucomas. DESIGN: Retrospective, noncomparative case series. PARTICIPANTS: All patients less than 18 years of age who underwent trabeculectomy with MMC from June 1991 through October 1997 were included. METHODS: The medical records of 29 consecutive patients (29 eyes) were reviewed. Data collected during routine patient follow-up were analyzed. Surgical outcome was evaluated using Kaplan-Meier life-table analysis. MAIN OUTCOME MEASURES: Clinical outcome assessment included intraocular pressure (IOP) control, visual acuity, and identification of complications. Successful IOP control was defined as 5 mmHg < or = final IOP < or = 21 mmHg, with or without antiglaucoma medications and without further glaucoma surgery or loss of light perception. Outcomes for the group of patients with primary infantile glaucoma were compared with those for the group with secondary glaucomas. RESULTS: Mean patient age was 6.4 +/- 4.4 years (range, 0.2-15.3 years). A variety of primary and secondary glaucomas were represented. Mitomycin-C (0.5 mg/ml) on a surgical sponge was applied to the episcleral surface for an average of 3.8 +/- 1.0 minutes (range, 1.5-5.0 minutes). Mean follow-up time for patients categorized as successes was 25.1 +/- 16.0 months (range, 5.5-59.7 months). The 12-, 24-, and 36-month life-table success rates for IOP control were 82%, 59%, and 59% respectively. There was no difference between the primary infantile glaucoma group and the secondary glaucoma group with respect to length of follow-up, rate of successful IOP control, and incidence of complications. Five patients (17%) experienced late bleb-related infection (BRI) at an average of 27.9 +/- 18.1 months (range, 5.4-55.5 months) after surgery. Other complications included hyphema, retinal detachment, late-onset bleb leak, flat anterior chamber, chronic hypotony, decompression retinopathy, suture abscess, and phthisis. CONCLUSIONS: Trabeculectomy with MMC may be useful in the management of childhood glaucomas in which goniotomy, trabeculotomy, or both have failed. However, the high incidence of BRI in this series over an extended follow-up interval dictates caution in using MMC as an adjunct in pediatric trabeculectomy.

Adolescent↗
PubMed2000

Potential role for Ginkgo biloba extract in the treatment of glaucoma.

Glaucoma is becoming recognized as a condition for which not only elevated intraocular pressure, but also non-pressure-dependent risk factors are responsible. New avenues of treatment into which investigations are being initiated include agents which could possibly improve blood flow to the eye and neuroprotective drugs. Only calcium channel blockers are presently available for such treatment in glaucoma, and these have not been widely adopted, in contrast to clinical trials involving a number of neuroprotectants in other neurologic disorders. Ginkgo biloba extract is freely available and has several biological actions which combine to make it a potentially important agent in the treatment of glaucoma: improvement of central and peripheral blood flow, reduction of vasospasm, reduction of serum viscosity, antioxidant activity, platelet activating factor inhibitory activity, inhibition of apoptosis, and inhibition of excitotoxicity. The effect of Ginkgo biloba extract as a potential antiglaucoma therapy deserves intensive scrutiny.

Animals↗
PubMed2000

Neuroprotection: is it already applicable to glaucoma therapy?

Many categories of both natural and synthetic compounds have been reported to have neuroprotective activity. These include not only antioxidants, N-methyl-D-aspartate receptor antagonists, inhibitors of glutamate release, calcium channel blockers, polyamine antagonists, and nitric oxide synthase inhibitors, but cannabinoids, aspirin, melatonin, and vitamin B-12. The lack of availability of specific neuroprotectant compounds in the United States and the lack of clinical trials examining the benefits of neuroprotective agents for glaucoma currently limit the use of these agents. This article provides a short overview of the concept of neuroprotection as it applies to glaucoma and suggests the possibility of neuroprotective activity that might be provided by compounds that are presently easily available.

Animals↗
PubMed2000

Quantitative assessment of the anterior segment using ultrasound biomicroscopy.

The development of ocular imaging devices has progressed rapidly during the past 10 years. Ultrasound biomicroscopy has revolutionized the evaluation of the anterior segment of the eye. The qualitative information gathered using this technology has contributed to our understanding of the pathophysiology of angle-closure glaucoma, pigmentary glaucoma, and a variety of other anterior segment disorders. However, the area of quantitative analysis of ultrasound biomicroscopic images remains largely to be developed. This review describes the role of ultrasound biomicroscopy in the measurement of the anatomic structures and their configurations within the anterior segment. Included are previously published and established methods as well as methods in their early stages of development. Application of quantitative image analysis techniques should yield significant information about mechanisms of appositional angle closure, dynamic functions of the iris, accommodation, and presbyopia.

Anterior Eye Segment↗
PubMed2000

Electrophysiologic assessment of photoreceptor function in patients with primary open-angle glaucoma.

PURPOSE: Electroretinograms to high-intensity flashes were obtained to determine the extent of rod and cone photoreceptor and postreceptor dysfunction in patients with primary open-angle glaucoma. METHODS: Full-field flash electroretinograms were obtained using brief high-intensity flashes. Dark-adapted (rod-dominated) and light-adapted (cone-dominated) electroretinogram responses were recorded to a "white" light as a function of flash intensity. The a-wave data were fitted with a model based on photopigment transduction to obtain values for the parameters of log Rmax (the maximum response) and log S (sensitivity). Oscillatory potentials were measured to the cone-dominated high-intensity flashes. Standard clinical 30 Hz flicker electroretinogram responses were recorded using a Grass photostimulator. RESULTS: Analysis of rod and cone a-wave data showed that log Rmax and log S values were within the normal range in nearly all of the patients. For some patients, oscillatory potentials were delayed beyond the normal range. CONCLUSION: Our results provide little evidence for widespread photoreceptor abnormalities in primary open-angle glaucoma.

Adult↗
PubMed2000

An attempt to detect glaucomatous damage to the inner retina with the multifocal ERG.

PURPOSE: To detect glaucomatous damage to the inner retina using the multifocal electroretinogram (mERG). METHODS: The stimulus array consisted of 103 hexagons with a mean luminance of 100 cd/m2 and a contrast of 50%. The mERG was recorded from 13 control subjects, 18 patients with open-angle glaucoma (OAG), 4 glaucoma suspects, and one patient with ischemic optic neuropathy (ION). Individual responses, as well as responses summed within quadrants or across the entire array, were measured in a number of ways. Humphrey visual fields were obtained for all patients, and the mean total deviation (MD) values for the 18 patients with OAG ranged from -2.2 to -18.2 with a mean (SD) of -7.3 (4.5). RESULTS: The mERG measure that best discriminated between the patients and the control subjects was the ratio of the amplitude at 8 msec after the peak response to the amplitude at the peak. Although the value of this ratio fell below the median of the control group for 16 of the 18 OAG patients, only 6 of these patients had ratios that fell below the normal range. Other measures of first- and second-order kernels did not do as well. Both within and across patients, the correlation between local field loss and the mERG ratio measure was poor. Furthermore, although in some patients the mERG waveform is clearly different from normal, in other patients (including the patient with ION) the waveform approximates the normal even in visual field areas with substantial sensitivity loss. CONCLUSIONS: Because glaucomatous damage is known to affect the ganglion cell axon, these data suggest that damage to ganglion cell axons is not a sufficient condition to produce changes in the mERG as measured here and that in patients with clear changes in mERG waveforms, these changes do not appear to be well localized and local waveforms are poorly correlated with local changes in field sensitivity.

Adult↗
PubMed2000

An interocular comparison of the multifocal VEP: a possible technique for detecting local damage to the optic nerve.

PURPOSE: To develop a quantitative measure of local damage to the ganglion cells/optic nerve based on an interocular comparison of multifocal visual evoked potentials (mVEP). METHODS: Multifocal VEPs were recorded from both eyes of six normal subjects and four patients; each eye was stimulated separately. Two of the patients had glaucoma, one had ischemic optic neuropathy, and one had unilateral optic neuritis. All four patients had considerably more damage in one eye than in the other, as indicated by their Humphrey visual fields. The multi-input procedure of Sutter was used to obtain 60 VEP responses to a scaled checkerboard pattern. The amplitude in each response was obtained using a root mean square measure of response magnitude. For each of the 60 pairs of responses, a ratio between the amplitude of the responses from the two eyes was obtained as a measure of the relative health of one eye compared with the other. The mean and SD of this ratio measure for the control group were used to specify confidence intervals for each of the 60 locations. All patients had Humphrey 24-2 visual fields performed. To allow a comparison of the mVEPs to the visual fields, a procedure was developed for displaying the results of both tests on a common set of coordinates. RESULTS: Except for a small interocular difference in timing attributable to nasotemporal retinal differences, the pairs of mVEP responses from the two eyes of the control subjects were essentially identical. Many of the pairs of responses from the patients were significantly different. In general, there was reasonably good agreement with the Humphrey 24-2 visual field data. Although some regions with visual field defects were not detected in the mVEP due to small responses from the better eye, other abnormalities were detected that were hard to discern in the visual fields. CONCLUSIONS: Local monocular damage to the ganglion cell/optic nerve can be quantitatively measured by an interocular comparison of the mVEP.

Adult↗
PubMed2000

The combined effect of brain-derived neurotrophic factor and a free radical scavenger in experimental glaucoma.

UNLABELLED: PURPOSE. Brain-derived neurotrophic factor (BDNF) had a limited effect on the survival of retinal ganglion cells (RGCs) in rats' eyes with elevated intraocular pressure (IOP). The combined treatment of BDNF and a nonspecific free radical scavenger N-tert-butyl-(2-sulfophenyal)-nitrone (S-PBN) was investigated on the RGCs in hypertensive eyes of rats. METHODS: Adult Wistar rats were separated into five groups: BDNF (0.5 microg) + S-PBN; BDNF (1. 0 microg) + S-PBN; BDNF (1.0 microg); S-PBN; and phosphate-buffered saline. Right eyes served as normal controls (n = 10). RGCs were labeled with 5% Fluoro Gold; injected into the superior colliculus. Three days after intratectal injection, the episcleral veins of the left eyes were cauterized. Intravitreal injection of BDNF was performed on days 5, 13, 21, and 29 after IOP elevation. S-PBN was injected intraperitoneally (100 mg/kg body wt) every 12 hours starting 30 minutes after cauterization. RESULTS: The survival of RGCs using BDNF treatment alone in moderately hypertensive eyes and systemic administration of S-PBN alone did not significantly rescue the RGCs. However, the combination of BDNF and S-PBN increased the survival of RGCs to 90.1%. CONCLUSIONS: Trophic factors and antioxidants have synergistic effects on rescuing RGCs from death in eyes with elevated IOP. Further studies of different combined treatment therapies may provide avenues to save RGCs from death in eyes with elevated IOP.

Animals↗
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

Noninfectious crystalline keratopathy after postoperative subconjunctival 5-fluorouracil.

PURPOSE: To describe a case of transient, noninfectious crystalline keratopathy after postoperative subconjunctival 5-fluorouracil. METHOD: Case report. Slit-lamp biomicroscopic examinations were performed during serial office examinations. RESULTS: A 69-year-old woman underwent an uncomplicated trabeculectomy with adjunctive sponge 5-fluorouracil application for 5 minutes in her left eye. Postoperative treatment included topical prednisolone acetate, ciprofloxacin, and scopolamine. She was initially examined with intrastromal corneal crystalline deposits 5 days after her first postoperative subconjunctival injection of 5-fluorouracil. The deposits completely disappeared 4 days later without addition to or change in treatment. CONCLUSION: Transient, noninfectious, crystalline, intrastromal corneal deposits may develop after adjunctive subconjunctival 5-fluorouracil administration.

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

Combined phacoemulsification and goniosynechialysis for uncontrolled chronic angle-closure glaucoma after acute angle-closure glaucoma.

OBJECTIVE: To evaluate combined phacoemulsification, posterior chamber intraocular lens (PCIOL) implantation, and goniosynechialysis (phaco-GSL) prospectively in eyes with more than 180 degrees of peripheral anterior synechiae (PAS) and uncontrolled intraocular pressure (IOP) when performed within 6 months of an attack of acute angle-closure glaucoma (ACG). DESIGN: Prospective, noncontrolled clinical trial. PARTICIPANTS: Patients who had presented with acute ACG and had persistently uncontrolled IOP despite successful laser iridotomy for pupillary block and argon laser peripheral iridoplasty for continued appositional closure after iridotomy. INTERVENTION: After the completion of phacoemulsification and posterior chamber lens implantation, goniosynechialysis was performed in 52 eyes of 48 patients. MAIN OUTCOME MEASURES: Postoperative visual acuity, IOP, extent of PAS, and number of medications, if any, required for IOP control. RESULTS: Intraocular pressure was less than 20 mmHg in 47 eyes (90.4%) without medications; 4 were controlled with medications and 1 required filtration. Mean extent of PAS was reduced from 310 degrees to 60 degrees. Peripheral anterior synechiae formation or IOP elevation did not recur after 3 months after surgery up to 6 years. Eight patients achieved 20/20 visual acuity, while 44 patients had less than 20/20 visual acuity. No patient had worse visual acuity after surgery compared to before surgery. CONCLUSION: Phaco-GSL and PCIOL implantation is effective in reducing PAS and IOP and improving visual acuity in eyes with persistent chronic ACG when performed within 6 months after treatment for acute ACG.

Acute Disease↗