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Biomedical subjects

R Ritch

Publications and source records attributed to R Ritch.

At least 91 records · Page 5Linked to original sources
PubMed1998

Latanoprost treatment for glaucoma: effects of treating for 1 year and of switching from timolol. United States Latanoprost Study Group.

PURPOSE: To determine the efficacy and safety of latanoprost treatment for 1 year in glaucoma patients, and to evaluate the effects of switching from timolol to latanoprost therapy. METHODS: Latanoprost 0.005% was topically applied once daily without masking for 6 months in 223 patients with elevated intraocular pressure after previous treatment with latanoprost once daily or 0.5% timolol twice daily for 6 months in a multicenter, randomized, double-masked, parallel group study. RESULTS: Compared with baseline values before treatment, a significant (P < .0001) diurnal reduction in intraocular pressure of 6 to 8 mm Hg was maintained with minimal fluctuation for the duration of treatment. When treatment was switched from timolol to latanoprost, intraocular pressure was reduced by 1.5 +/- 0.3 mm Hg (mean +/- SEM; 8% change in intraocular pressure; 31% of the intraocular pressure reduction produced by timolol; P < .001) compared with the change in intraocular pressure in patients remaining on latanoprost therapy. Of the patients initially enrolled, 95% successfully completed treatment. There was a slight overall increase in conjunctival hyperemia in patients who switched from timolol to latanoprost, but no change in those who continued latanoprost. The timolol-induced reduction of resting heart rate returned to baseline levels after switching to latanoprost. Of the 247 patients treated with latanoprost during the masked and/or open-label studies, 12 (5%) demonstrated a definite (n = 4) or possible (n = 8) increase in iris pigmentation. CONCLUSIONS: Latanoprost is a well-tolerated ocular hypotensive agent that appears to be more effective than timolol in reducing intraocular pressure. The increase in iris pigmentation appears to be harmless but requires further investigation.

Adult↗
PubMed1998

Visual evoked potential assessment of the effects of glaucoma on visual subsystems.

The purpose of this study is to test the hypothesis that glaucoma leads to selective deficits in parallel pathways or channels. Sweep VEPs were obtained to isolated-check stimuli that were modulated sinusoidally in either isoluminant chromatic contrast or in positive and negative luminance contrast. Response functions were obtained from 14 control subjects, 15 patients with open-angle glaucoma, and seven glaucoma suspects. For all three groups of subjects we found characteristic differences between the VEP response functions to isoluminant chromatic contrast stimuli and to luminance contrast stimuli. The isoluminant chromatic stimulus conditions appeared to favor activity of the P-pathway, whereas the luminance contrast stimuli at low depths of modulation favored M-pathway activity. VEP responses for patients with OAG were significantly reduced for chromatic contrast and luminance contrast conditions, whereas VEP responses for glaucoma suspects were significantly reduced only for the 15-Hz positive luminance contrast condition. Our results suggest that both M- and P-pathways are affected by glaucoma.

Adult↗
PubMed1998

High-resolution ultrasound biomicroscopy of the pars plana and peripheral retina.

OBJECTIVE: This study aimed to evaluate the ability and role of ultrasound biomicroscopy in imaging the peripheral retina, pars plana, and anterior choroid. DESIGN: The study design was a case series. PARTICIPANTS: Seventeen eyes of 17 patients with a variety of clinical diagnoses involving the anterior portion of the posterior segment were studied. INTERVENTION: High-frequency (50 MHz), high-resolution (50 microns) ultrasound biomicroscopy was performed. RESULTS: Ultrasound biomicroscopy was capable of imaging the peripheral retina, pars plana, and anterior choroid. Images had features consistent with known histopathology. Retinoschisis consisted of one thin hyper-reflective echo and could be differentiated from a retinal detachment, which was thicker and formed a bilayered echo. A choroidal effusion could be identified as an echolucent space within the suprachoroidea, whereas a choroidal hemorrhage was moderately echodense. Inflammatory diseases, such as a sarcoid granuloma, pars planitis, and Harada's disease, were characterized by different forms of uveal thickening. A ciliochoroidal nevus was internally hyporeflective and could be measured accurately and localized. CONCLUSIONS: Imaging of the peripheral retina, pars plana, and anterior choroid is possible with ultrasound biomicroscopy and may aid in the diagnosis and management of pathology involving this region.

Adolescent↗
PubMed1998

Novel trabecular meshwork inducible glucocorticoid response mutation in an eight-generation juvenile-onset primary open-angle glaucoma pedigree.

OBJECTIVE: This study aimed to update a large kindred with juvenile-onset primary open-angle glaucoma (POAG) first described in 1940 and to identify the underlying genetic cause of the disease. DESIGN: Molecular genetic study of a single kindred, including clinical examination, retrospective review of clinical and family history records, linkage analysis, and mutation screening. PARTICIPANTS: The retrospective review included 957 members of a single large family. The linkage study included 40 members of 1 branch of the family in which juvenile-onset POAG is segregating in an autosomal-dominant pattern. Mutation screening included 15 at-risk family members with juvenile-onset POAG, probands of 40 families with adult-onset POAG, probands of 11 additional unrelated juvenile-onset POAG families, and 43 unrelated normal control subjects. INTERVENTION: Clinical and family history records were obtained, ophthalmologic examinations were performed, and blood samples were drawn for use in genotyping. MAIN OUTCOME MEASURES: Allele sizes of microsatellite repeat genetic markers from the vicinity of the GLC1A glaucoma gene on chromosome 1q were assigned based on size fractionation of DNA fragments generated by polymerase chain reaction (PCR). Linkage was established by the method of lod scores. Mutations were identified by determination of the DNA sequence of PCR products amplified from the trabecular meshwork inducible glucocorticoid response (TIGR) gene. Glaucoma status for purposes of linkage and mutation analysis was based on a combination of ophthalmologic examination, clinical records, family history, and previously published information. For some individuals reported in the pedigree, but not included in the genotyping studies, less information was available as presented in the text and tables. RESULTS: Autosomal-dominant POAG was confirmed or reported for 78 members of an 8-generation family. Linkage analysis showed significant evidence for linkage of juvenile-onset POAG in one branch of the family to D1S452 (maximum lod score of 6.42 at a recombination fraction of 0.00) and other markers in the vicinity of the GLC1A gene on chromosome 1q. Screening of the TIGR gene identified a mutation that results in substitution of asparagine for isoleucine at codon 477 near the carboxyterminal end of the protein. CONCLUSIONS: The authors' findings strongly suggest that the juvenile-onset POAG locus in this family is the GLC1A locus and that the underlying cause of the disease is the IIe477Asn TIGR mutation that cosegregates with juvenile-onset POAG in one branch of this large family. Lack of samples from deceased individuals prevented the authors from determining whether reported adult-onset cases in this family could also be attributed to the IIe477Asn TIGR mutation. Absence of the IIe477Asn TIGR mutation from other juvenile- and adult-onset POAG families implies that this TIGR mutation is not a common cause of glaucoma.

Adolescent↗
PubMed1998

Ultrasound biomicroscopic localization and evaluation of intraocular foreign bodies.

PURPOSE: To evaluate the ultrasound biomicroscopic appearance of anterior segment foreign bodies under clinical and experimental conditions. METHODS: Ultrasound biomicroscopy was performed on 4 eyes of 4 patients referred for evaluation of anterior segment trauma and known or suspected intraocular foreign body. Imaging of wood, aluminum, concrete, and glass foreign bodies was performed in the anterior chamber of a human cadaver eye. RESULTS: Ultrasound biomicroscopy verified the location of a foreign body in two patients and identified occult foreign bodies in two others. Under clinical and experimental conditions, intraocular aluminum and glass produced comet tail artifacts. Under experimental conditions intraocular wood and concrete produced shadowing artifacts. CONCLUSION: Ultrasound biomicroscopy provides useful information in the evaluation of known and occult anterior segment foreign bodies. Ultrasound patterns of shadowing and comet tail may help differentiate foreign body materials.

Adolescent↗
PubMed1998

Lack of cross-reactive allergic response to brimonidine in patients with known apraclonidine allergy.

PURPOSE: To assess the allergenic potential of topical brimonidine 0.2% in patients shown to be allergic to apraclonidine 0.5%. METHODS: Eighteen glaucoma patients who developed allergy to apraclonidine were enrolled. Allergy was graded and documented photographically. Apraclonidine was then discontinued until the allergy resolved. Grading and photography were repeated, following which treatment with brimonidine was initiated. Patients were examined 1 h after the initial drop of brimonidine, twice weekly for 6 weeks, and at 3 monthly intervals thereafter. All other anti-glaucoma medications were continued. RESULTS: Mean patient age was 66.3 +/- 14.9 years (range 33.5-89.3 years). The mean time to apraclonidine allergy from initial exposure was 12.9 +/- 12.9 months (range 2.1-46.8 months). For the 10 patients rechallenged with apraclonidine, the mean time to allergy was 13.6 +/- 10.2 days (range 3-32 days). Mean duration of brimonidine therapy was 140.7 +/- 66.2 days (range 14-286 days), with 11 patients reaching at least 150 days of follow-up. Two patients developed symptomatic brimonidine allergy at 138 and 201 days respectively. For those patients who did not develop symptoms of allergy to brimonidine, there was no significant change in any of the parameters by which allergy was graded throughout the study. CONCLUSIONS: Patients with known apraclonidine allergy do not develop an early allergic response to brimonidine. These data rule against a cross-reactive allergic response between these two alpha 2-adrenoreceptor agonists.

Adrenergic alpha-Agonists↗
PubMed1998

New patterns of infecting organisms in late bleb-related endophthalmitis: a ten year review.

PURPOSE: To report the risk factors, causative organisms and visual outcomes in patients with late-onset bleb-related endophthalmitis. METHODS: Medical records of all patients with the clinical diagnosis of late-onset bleb-related endophthalmitis undergoing vitreous aspirates for culture at our institution from January 1987 to July 1996 were reviewed. Late-onset bleb-related endophthalmitis was defined as conjunctival injection, bleb purulence and intraocular inflammation developing at least 1 month following filtering surgery. RESULTS: Forty-nine cases of bleb-related endophthalmitis developed in 42 patients (23 men, 19 women). Mean patient age was 62.1 +/- 19.3 years (range 5-94 years). Thirty-nine patients underwent prior filtering surgery (superior trabeculectomy, 24 eyes; inferior trabeculectomy, 10 eyes; combined superior trabeculectomy/cataract extraction, 4 eyes; posterior lip sclerectomy, 1 eye) and 3 had inadvertent blebs following cataract extraction. Endophthalmitis developed an average of 25.4 +/- 23.5 months (range 1-96 months) post-operatively. Antifibrosis agents were used in 25 of 39 eyes undergoing filtering surgery (mitomycin C, 13 eyes; 5-fluorouracil, 12 eyes). Bleb leaks were documented in a total of 32 of 49 (65%) cases either before or at the time of endophthalmitis diagnosis. Vitreous cultures were positive in 42 of 49 (86%) cases. The most frequently cultured organisms were Staphylococcus aureus (13), Staphylococcus epidermidis (12), Streptococcus species (8) and Haemophilus influenzae (2). A final visual acuity of 20/400 or better was achieved in 32 of 49 (65%) cases. CONCLUSIONS: Staphylococcal species were the most frequently cultured organisms in this series and may be associated with better visual outcomes. Although a causal relationship cannot be established, these results suggest a strong association between bleb leaks and endophthalmitis.

Adolescent↗
PubMed1998

[Family history of glaucoma and risk factors in pigmentary glaucoma. A new clinical study].

BACKGROUND: Whether a family history of glaucoma (FHG) in patients with pigmentary glaucoma (PG) is a prognostical indicator, is unknown. Therefore the aim of this study was to evaluate the influence of FHG on the severity of the disease in PG and pigment dispersion syndrome (PDS). Furthermore risk factors in PG and PDS were evaluated. METHODS: The findings of 207 patients with PG and PDS, who were able to give information about FHG, were evaluated (149 PG, 43 PDS with ocular hypertension (OH), 15 PDS without OH). RESULTS: Significance of FHG: FHG was found in 39.1%, and in one third of the patients more than one relative had the disease. FHG was found in PG not more frequent than in PDS. Pigmentary glaucomas in advanced stages of the disease did not have a higher incidence of FHG than patients in beginning stages. Out of 207 patients with PG and PDS 71% were male and 29% female (p < 0.001). In patients with FHG the share of men was 64.2% and not significantly different to the group without FHG with 75.4%. The sex distribution in parents and grandparents having a glaucomatous disease was 1:1. RISK FACTORS: The pf1p4nts with and without FHG in PDS with and without OH, PG, and within the different stages of visual field loss, showed no significant differences in risk factors, for example in maximum intraocular pressure, refraction and cup-disc ratio. Myopia: Patients with PG had a significantly higher myopia than patients with PDS (p < 0.01). The higher the myopia, the earlier the disease was diagnosed (p = 0.008). Krukenberg spindle: During miotic therapy the Krukenberg spindle decreased in the upper half of the cornea. Time of diagnosis: PG was diagnosed at a higher age compared to PDS. CONCLUSION: FHG does not influence the severity of the disease in PG. Family history of glaucoma is a risk factor in patients with PG, but no prognostical indicator. Patients with FHG do not have primarily larger cup-disc ratios than patients without FHG. Myopia is a risk factor.

Adolescent↗
PubMed1998

Mutations of the forkhead/winged-helix gene, FKHL7, in patients with Axenfeld-Rieger anomaly.

Genetic linkage, genome mismatch scanning, and analysis of patients with alterations of chromosome 6 have indicated that a major locus for development of the anterior segment of the eye, IRID1, is located at 6p25. Abnormalities of this locus lead to glaucoma. FKHL7 (also called "FREAC3"), a member of the forkhead/winged-helix transcription-factor family, has also been mapped to 6p25. DNA sequencing of FKHL7 in five IRID1 families and 16 sporadic patients with anterior-segment defects revealed three mutations: a 10-bp deletion predicted to cause a frameshift and premature protein truncation prior to the FKHL7 forkhead DNA-binding domain, as well as two missense mutations of conserved amino acids within the FKHL7 forkhead domain. Mf1, the murine homologue of FKHL7, is expressed in the developing brain, skeletal system, and eye, consistent with FKHL7 having a role in ocular development. However, mutational screening and genetic-linkage analyses excluded FKHL7 from underlying the anterior-segment disorders in two IRID1 families with linkage to 6p25. Our findings demonstrate that, although mutations of FKHL7 result in anterior-segment defects and glaucoma in some patients, it is probable that at least one more locus involved in the regulation of eye development is also located at 6p25.

Amino Acid Sequence↗
PubMed1998

Role of ultrasound biomicroscopy in the differentiation of block glaucomas.

Ultrasound biomicroscopy has allowed us to elucidate the anatomic variations and underlying mechanisms in angle-closure glaucoma. Four levels of anatomic block can be distinguished, and a specific approach to treatment exists for each level to correct the abnormal forces leading to closure of the angle. As more quantitative approaches are developed, our understanding of these disorders will become increasingly sophisticated.

Anterior Eye Segment↗
PubMed1998

Recurrent bleb infections.

AIM: To report the patient characteristics, causative organisms, and clinical outcomes in patients with recurrent bleb related ocular infections. METHODS: The medical records of all patients diagnosed with bleb related ocular infection at the New York Eye and Ear Infirmary over a 10 year period were reviewed. Recurrent bleb infection was defined as at least two episodes of bleb purulence with or without associated intraocular inflammation separated by a quiescent period of at least 3 months. RESULTS: Recurrent bleb infections developed in 12 eyes of 12 patients (10 men, two women) a mean of 16.3 (SD 17.9) months (range 3-51 months) after the initial infection. Two patients developed a third episode 3 and 20 months, respectively, after the second infection, yielding a total of 14 recurrent infection episodes. Recurrent infection developed after trabeculectomy in 11 eyes (adjunctive 5-fluorouracil, nine eyes; mitomycin C, one eye; no antifibrosis agent, one eye) and following cataract extraction with inadvertent bleb formation in one eye. Four (36.4%) of the filtered eyes had undergone trabeculectomy at the inferior limbus. The mean follow up time from filtering surgery to the first bleb related infection was 28 months for the nine patients treated with 5-fluorouracil and 14 months for the single patient treated with mitomycin C. 11 (78.6%) cases had a documented bleb leak in the 4 week period before or at the time of recurrent infection. Topical, prophylactic antibiotics had been used in 7/14 (50%) cases. The same organism was cultured from the initial and recurrent infections in 2/14 (14.3%) cases. CONCLUSION: Eyes that have been successfully treated for bleb related infection remain at risk for recurrent infection. No apparent correlation exists between organisms responsible for the initial and recurrent infections. The increased rate of recurrent bleb related infection in patients receiving adjunctive 5-fluorouracil compared to mitomycin C may have been related to the longer follow up of the 5-fluorouracil eyes.

Adult↗
PubMed1998

Peripapillary nerve fiber layer thickness measurement reproducibility using scanning laser polarimetry.

PURPOSE: The authors assess the reproducibility of retinal nerve fiber layer (RNFL) thickness measurements using scanning laser polarimetry. METHODS: The right eyes of five healthy individuals were scanned by two trained operators (S.T.H., H.I.) using the Nerve Fiber Analyzer II (Laser Diagnostic Technologies, Inc., San Diego, CA, U.S.A.). Each participant was scanned six consecutive times per session for five sessions carried out over separate days within a two-week period. Intra- and interoperator measurement reproducibility was assessed. RESULTS: Intraoperator reproducibility was high. Mean coefficients of variation for total RNFL thickness measurements were 4.48 +/- 1.76% and 4.92 +/- 2.32% for operators 1 and 2, respectively. Interoperator reproducibility was high (p = 0.20-0.93) if a single ellipse was applied to the images of both examiners. However, measurement reproducibility worsened if each operator created his own measurement ellipse (p < or = 0.05 for 3 out of 5 participants). CONCLUSION: Interoperator error in image analysis can be minimized by using a single ellipse for the baseline and all subsequent scans even if subsequent scans are acquired by different operators.

Adult↗
PubMed1998

Pericardial patch grafts in glaucoma implant surgery.

PURPOSE: The authors determine the safety and effectiveness of pericardial patch grafts in glaucoma implant surgery. METHODS: A retrospective chart review was conducted on all patients who underwent a glaucoma implant procedure with the use of a pericardial patch graft to cover the subconjunctival portion of the tube at The New York Eye and Ear Infirmary between September 1, 1995 and June 30, 1996. Charts were assessed for evidence of delle formation, graft rejection, graft-related infection, graft thinning, or tube erosion. RESULTS: Forty-four eyes of 44 patients were enrolled. Mean follow-up was 10.2 +/- 4.0 months (range, 2.3 to 18.6 months). Infection, tube erosion, graft rejection, and graft-related inflammation did not occur. Five eyes were noted to have asymptomatic thinning of the patch without evidence of tube erosion. CONCLUSIONS: Preserved human cadaveric pericardial patch grafts appear to be well-tolerated for use with glaucoma drainage devices. As with other grafting material, potential for graft thinning is possible and further long-term experience is needed.

Adolescent↗
PubMed1998

Late hypotony after cataract extraction due to a scleral fistula: a technique for surgical correction.

The authors report the use of a surgical procedure for the correction of a scleral fistula in a patient with late hypotony after cataract surgery. Trephination of necrotic tissue lining the scleral fistula with a double scleral patch technique was performed. Four months later, the patient's vision had improved to 20/40, with improvement of the macular folds and an intraocular pressure of 10 mm Hg. The authors conclude that the use of a double-patching technique is effective in the repair of scleral fistulas. The technique allows one to avoid more risky repair procedures that involve a greater area of tissue excision.

Aged↗
PubMed1998

Reproducibility of retinal thickness measurements in normal eyes using optical coherence tomography.

BACKGROUND AND OBJECTIVE: To determine the reproducibility of retinal thickness measurements in normal eyes using optical coherence tomography (OCT). PATIENTS AND METHODS: Multiple 3.20-mm vertical cross-sectional images through the center of fixation of consecutive patients with normal results on ocular examinations were obtained. Each image was divided into seven 320-micron segments. Regional retinal thicknesses for each section were measured using both the manually assisted (requiring observer localization of reflectivity peaks) and the automated modes (observer-independent measurement) of the computer software. RESULTS: Eighteen right eyes were studied. The mean coefficient of variation was less than 10% for all locations using the manually assisted method (average standard deviation less than 17 microns [range 9 to 16 microns]). The automated method was less reliable, with a coefficient of variation greater than 10% for locations within 500 microns of fixation. Automated measurements at fixation were the least reproducible because of poor internal limiting membrane reflectivity. CONCLUSION: OCT is capable of reproducible measurement of retinal thickness in normal eyes. Computer-driven, automated measurement of retinal thickness within 500 microns of fixation needs to be refined and its reproducibility reassessed in this region.

Adult↗