Biomedical subjects

Robert Ritch

Publications and source records attributed to Robert Ritch.

At least 55 records · Page 3Linked to original sources

PubMed2004

Absence of myocilin and optineurin mutations in a large Philippine family with juvenile onset primary open angle glaucoma.

PURPOSE: To analyze the role of the two primary open angle glaucoma (POAG) genes, myocilin (MYOC) and optineurin (OPTN), in a large Philippine family segregating autosomal dominant juvenile onset open angle glaucoma (JOAG). METHODS: The coding sequences of the MYOC and OPTN genes were screened in 27 family members by polymerase chain reaction and direct sequencing. The specific MYOC promoter polymorphism (MYOC.mtl) was identified by restriction endonuclease assay. All of the ABI MD-10 microsatellite markers on chromosomes 1, 2, 3, 7, 8, and 10, which harbor the six known POAG loci, were analyzed for linkage with POAG. RESULTS: No mutation was identified in this large kindred. Instead, three polymorphisms (-80G->A, -1000G->C, R76K) in MYOC and four polymorphisms (T34T, M98K, R545Q, IVS7+24G->A) in OPTN were found. All markers flanking the six known POAG loci gave LOD scores not more than 1.1. Non-parametric linkage analysis for all these markers resulted in p values more than 0.05. CONCLUSIONS: Both mutation testing and linkage analysis provide strong evidence against MYOC and OPTN being the causative gene in this large family. It indicates that unidentified genes will underlie the occurrence of glaucoma in this family.

Adult↗

PubMed2004

Phenotypic and molecular assessment of seven patients with 6p25 deletion syndrome: relevance to ocular dysgenesis and hearing impairment.

BACKGROUND: Thirty-nine patients have been described with deletions involving chromosome 6p25. However, relatively few of these deletions have had molecular characterization. Common phenotypes of 6p25 deletion syndrome patients include hydrocephalus, hearing loss, and ocular, craniofacial, skeletal, cardiac, and renal malformations. Molecular characterization of deletions can identify genes that are responsible for these phenotypes. METHODS: We report the clinical phenotype of seven patients with terminal deletions of chromosome 6p25 and compare them to previously reported patients. Molecular characterization of the deletions was performed using polymorphic marker analysis to determine the extents of the deletions in these seven 6p25 deletion syndrome patients. RESULTS: Our results, and previous data, show that ocular dysgenesis and hearing impairment are the two most highly penetrant phenotypes of the 6p25 deletion syndrome. While deletion of the forkhead box C1 gene (FOXC1) probably underlies the ocular dysgenesis, no gene in this region is known to be involved in hearing impairment. CONCLUSIONS: Ocular dysgenesis and hearing impairment are the two most common phenotypes of 6p25 deletion syndrome. We conclude that a locus for dominant hearing loss is present at 6p25 and that this locus is restricted to a region distal to D6S1617. Molecular characterization of more 6p25 deletion patients will aid in refinement of this locus and the identification of a gene involved in dominant hearing loss.

Abnormalities, Multiple↗

PubMed2004

Stem cell therapy for ocular disorders.

Cell injury or degeneration occurs in a number of blinding diseases. Therapy has classically consisted of preventing the initial injury or increasing the resistance of cells to injury (cytoprotection). Recently, it has become possible to repopulate tissue compartments with stem cells. This article presents a current summary of ocular stem cell research and applications to disease. It is based on presentations and discussions from the July 2002 international conference "Stem Cells and Glaucoma" sponsored by the Glaucoma Foundation. This meeting, the first of its kind, brought together ophthalmologists, geneticists, immunologists, and developmental biologists working on stem cell development and applications in both human and animal models.

Animals↗

PubMed2004

A method for comparing electrophysiological, psychophysical, and structural measures of glaucomatous damage.

OBJECTIVE: To develop a method for comparing multifocal visual-evoked potential (mfVEP) responses and behaviorally determined visual fields with structural measures of the optic nerve head. METHODS: Humphrey 24-2 visual fields and mfVEPs were obtained from each eye of 20 patients with open-angle glaucoma. Monocular and interocular analyses were performed to identify locations with abnormal mfVEP responses. Optic discs were assessed with a confocal scanning laser ophthalmoscope (Heidelberg Retina Tomograph II). The image of the optic nerve head was divided into 6 sectors. The rim and disc area measurements for each sector were compared with those in a normal database using Moorfields regression analysis. The optic nerve head measurements for the 6 sectors were related to the Humphrey visual field locations and the 60 sectors of the mfVEP display. RESULTS: Of 240 sectors tested (40 eyes x 6 sectors), 18.8% on Humphrey visual field, 22.1% on mfVEP, and 10.8% on confocal scanning laser ophthalmoscopic testing were significantly different from those of control subjects. There were no significant deficits in 165 sectors. There was agreement for 86.7% of the sectors when the Humphrey visual field and mfVEP results were compared. The confocal scanning laser ophthalmoscopic results were in agreement for 84.6% of these sectors. CONCLUSIONS: The method used allows for a comparison among measures of visual function and a structural measure of the optic nerve head. In general, the results of the functional and structural measures showed agreement; however, there were clear examples of disagreements that merit further study.

Adult↗

PubMed2004

Long-term success of argon laser peripheral iridoplasty in the management of plateau iris syndrome.

OBJECTIVE: To document the long-term effect of argon laser peripheral iridoplasty (ALPI) in eyes with plateau iris syndrome. DESIGN: Retrospective, noncomparative, interventional case series. SETTING: New York Eye and Ear Infirmary. METHODS: The charts of all patients with plateau iris syndrome treated with ALPI from 1982 to 1991 and subsequently followed for 6 or more years were retrospectively reviewed. Patients with lens-related mechanisms contributing to angle closure (e.g., phacomorphic or malignant glaucoma) were excluded. MAIN OUTCOME MEASURES: Necessity for repeat ALPI and/or any additional means of intervention. RESULTS: A total of 26 ALPI procedures were performed in 23 eyes of 14 patients (4 men, 10 women). The mean age was 61+/-8.7 years. The mean follow-up was 78.9+/-8.0 months (range, 72-188 months). The angle in 20 of 23 (87.0%) eyes remained open throughout the entire follow-up period after only 1 treatment with ALPI. In 3 eyes, there was gradual reclosure of the angle 5 to 9 years after initial ALPI, but they were readily reopened and maintained open by a single repeat treatment. No filtration surgery was necessary in any eye during follow-up. CONCLUSIONS: ALPI is highly effective in eliminating residual appositional closure after laser iridotomy caused by plateau iris syndrome. The effect is maintained for years, although a small proportion of patients might require retreatment.

Aged↗

PubMed2004

The Proview phosphene tonometer fails to measure ocular pressure accurately in clinical practice.

PURPOSE: To evaluate the Proview Eye Pressure Monitor as a medical instrument and as a technique for enabling a patient to obtain an accurate measure of his or her intraocular pressure (IOP). DESIGN: An experimental laboratory evaluation and an independent prospective clinical study to test the reproducibility and accuracy of the Proview technique relative to Goldmann applanation tonometry. PARTICIPANTS: For the laboratory study, we analyzed 3 tonometers, each packaged as a Proview Eye Pressure Monitor by Bausch & Lomb. In the independent prospective experimental study, 137 subjects participated, consisting of healthy volunteers and glaucoma patients. METHODS: For laboratory testing, we held each tonometer with a micrometer to assure controlled positioning and pressed its sensing tip against a force meter that produced a calibrated, digital force reading. For clinical testing, we taught subjects (n = 137) to use the Proview technique in accordance with the manufacturer's instructions. Each subject obtained 5 measurements with each of the 5 different Proview devices. A clinician measured the IOP using Goldmann applanation tonometry. MAIN OUTCOME MEASURES: We measured the absolute value, linearity, and repeatability of the force meter readings on the tonometers during the instrument laboratory evaluation. The accuracy was evaluated by comparing the Proview measurements to the Goldmann applanation measurements. Reproducibility of clinical Proview measurements was also measured. All measurements were in mmHg during the clinical evaluation. RESULTS: Laboratory: There was a linear relationship between the pressures read by the Proview tonometers and known forces. The Proview tonometers read the maximum pressure applied. Clinical: The Proview technique is simple to use because it was comfortable and reproducible, with an average variance of the measurements by the same patient of 3.4 mmHg(2). Other variables besides IOP seem to affect the Proview pressure measurements, as seen in the large scatter in our data, measured by our correlation coefficient of r = 0.41. The sensitivity of the Proview technique to detect patients with high IOP (which we defined as a Goldmann pressure of >/=22 mmHg) is low; the Proview pressure identified only 18% (4/22) of these patients. CONCLUSIONS: The Proview instrument and technique were reproducible. However, the Proview tonometer seems not to be reliable as an indicator of IOP. The sensitivity for detecting high IOP was low in this cohort, and the agreement with Goldmann applanation was poor for some individuals. This brings into question the underlying assumption that a force proportional to the IOP generates phosphenes.

Adolescent↗

PubMed2004

Effect of pupillary dilation on retinal nerve fiber layer thickness measurements using optical coherence tomography.

PURPOSE: To evaluate the effect of pupillary dilation on retinal nerve fiber layer thickness (RNFL) measurements using optical coherence tomography (OCT-3). METHODS: Randomly chosen eyes of healthy individuals were scanned before and after pupillary dilation by two trained operators (R.G.O., R.V.) using OCT-3 (Carl Zeiss Meditec, Inc., Dublin, CA). Fast and regular RNFL (256 A-scans) OCT-3 protocols (software version A1.1) were used in each scanning session. RNFL thickness measurements before and after dilation were compared. RESULTS: Ten eyes of 10 subjects (6 females, 4 males) were enrolled. Mean age was 32.0 +/- 11.2 years (range, 21 to 52 years). Mean pupillary diameter before and after dilation was 2.9 +/- 0.6 mm and 7.6 +/- 0.8 mm, respectively (P < 0.0001, paired t-test). There was no significant difference in RNFL thickness measurements before and after dilation using both fast and regular RNFL protocols (P > or = 0.05 for all comparisons, paired t-test). Mean coefficients of variation for mean RNFL thickness measurements were 15.3% before and 13.7% after dilation for operator 1; and 10.8% before and 12.7% after dilation for operator 2 for the fast RNFL protocol and 11.3% versus 10.4% and 12.9 versus 11.1%, respectively, for the regular RNFL protocol. CONCLUSION: Pupillary dilation is not necessary in all subjects to obtain reproducible RNFL thickness measurements using OCT-3.

Adult↗

PubMed2004

Scanning protocol choice affects optical coherence tomography (OCT-3) measurements.

PURPOSE: To determine the optimal OCT-3 scanning protocol. METHODS: Normal subjects, ocular hypertensive, and open-angle glaucoma patients were enrolled. The "fast" RNFL scan protocol consists of 3 consecutive circular scans, each containing 256 A-scans obtained in a single 1.92 second session. The "regular" RNFL scan protocol contains 3 separate circular scans, each of which consists of 512 A-scans and is obtained in 1.28 seconds (total 3.84 seconds). A customized 256-point scan was created from the 512-point "regular" RNFL scan by extracting the RNFL measurements from every second point. Mean RNFL thickness measurements and mean coefficients of variation (CV) were calculated for each of the scan types. RESULTS: Thirty-one eyes with visual field defects (31 glaucoma eyes) and 30 eyes with normal fields (10 normal and 20 ocular hypertensive eyes) were enrolled. There was no difference in RNFL thickness or CV between fast, regular, or customized RNFL scans in the eyes with VF defects (P > 0.05 for all comparisons). Although eyes with normal fields showed no difference in CV between fast, regular, and customized RNFL scans (P > 0.05 for all comparisons), there was a thicker RNFL measurement using the fast RNFL scan (P = 0.01). CONCLUSIONS: Optimal sampling density for OCT-3 assessment of parapapillary RNFL thickness is not more than 256 axial determinations. Although both scanning protocols have good reproducibility, the scanning protocol should remain constant during serial OCT-3 evaluation.

Adult↗

PubMed2004

Macular and retinal nerve fiber layer thickness measurement reproducibility using optical coherence tomography (OCT-3).

PURPOSE: To assess the reproducibility of retinal nerve fiber layer thickness and macular thickness measurements using OCT-3. METHODS: Randomly chosen eyes of healthy individuals were scanned following pupillary dilation by two trained operators (RGO, RV) using OCT-3 (software version A1.1, Carl Zeiss Meditec, Inc., Dublin, CA), three times on separate days within a one-month period. Fast and regular macula (128 A-scans), and fast and regular RNFL (256 A-scans) scanning protocols were performed. Intra- and interoperator measurement reproducibility was evaluated. RESULTS: Ten eyes of 10 subjects (6 females, 4 males) were enrolled. Mean age was 32 +/- 11.2 years (range, 21 to 52 years). Intraoperator reproducibility was high for both macular and RNFL thickness measurements. Mean coefficients of variation (CV) for mean total RNFL thickness measurements ranged from 6.9 +/- 6.4% to 8.0 +/- 3.5% for operators 1 and 2 in fast and regular RNFL protocols. Mean CV for mean macular thickness measurements ranged from 4.7 +/- 2.6% to 6.4 +/- 5.5% for operator 1 and 2 in fast and regular macula protocols. There was no difference in mean total RNFL and mean foveal thickness measurements performed on different days (P > 0.05 for all measurements in all protocols, for operators 1 and 2, ANOVA). Interoperator reproducibility was high for both macular and RNFL thickness measurements (P > 0.05 for all measurements in all protocols, paired t test). CONCLUSION: OCT-3 RNFL and macular thickness measurements are reproducible in normal eyes. These results should be validated in ocular hypertensive and glaucomatous eyes.

Adult↗

PubMed2004

Characterization and prevalence of PITX2 microdeletions and mutations in Axenfeld-Rieger malformations.

PURPOSE: Mutations of the homeodomain protein PITX2 produce Axenfeld-Rieger (AR) malformations of the anterior chamber, an autosomal dominant disorder accompanied by a 50% risk of glaucoma. Twenty-nine mutations of PITX2 have been described, with a mutational prevalence estimated between 10% and 60% in AR. In the current study, the possible role of altered PITX2 gene dosage in the etiology of AR was investigated. Gross gene deletions and duplications should alter PITX2 activity analogously to hypomorphic and hypermorphic mutations, respectively. METHODS: Sixty-four patients with AR, iridogoniodysgenesis (IGD), iris hypoplasia (IH), or anterior segment dysgenesis (ASD) were screened for PITX2 mutations by sequencing. PITX2 gene dosage was concurrently examined in these patients by real-time quantitative PCR. Microsatellite markers were used to map 4q25 microdeletions at a contig scale, as well as for haplotype analysis in an extended AR kindred. An additional 27 patients with other assorted ocular phenotypes were evaluated by similar methods, amounting to a total of 91 cases analyzed. RESULTS: Three novel mutations of PITX2 (4.7%) were identified among 64 patients with AR, IGD, IH, or ASD. Deletions of PITX2 were as frequent as mutations in our sample. Chromosome 4q25 microdeletions were physically mapped relative to several microsatellite markers in each patient. Cosegregation of AR and a PITX2 deletion was demonstrated in an extended kindred. CONCLUSIONS: Point mutations and gross deletions of PITX2 appear to produce an equivalent haploinsufficiency phenotype. Quantitative PCR is an efficient means of detecting causative PITX2 deletions in patients with AR and may increase the detection rate at this locus.

Anterior Eye Segment↗

PubMed2004

Detecting early to mild glaucomatous damage: a comparison of the multifocal VEP and automated perimetry.

PURPOSE: To gain better understanding of the relationship between abnormalities detected by the multifocal VEP (mfVEP) compared with those detected by static achromatic, automated perimetry in patients with glaucoma. METHODS: Fifty patients were studied who had open-angle glaucoma that met the following criteria: (1) a mean deviation (MD) of better than -8 dB in both eyes on the 24-2 Humphrey visual field (HVF) test (Carl Zeiss Meditec, Dublin, CA); and (2) glaucomatous damage in at least one eye, as defined by a glaucomatous optic disc and an abnormal 24-2 HVF test result (pattern standard deviation [PSD] <5% and/or glaucoma hemifield test [GHT] results outside normal limits). Monocular mfVEPs were obtained from each eye by using a pattern-reversal dartboard array, 44.5 degrees in diameter, which contained 60 sectors. Recording electrodes were placed at the inion (I) and I+4 cm, and also at two lateral locations up 1 cm and over 4 cm from I. Monocular and interocular mfVEP probability plots were derived by comparing the results with those of normal control subjects. For both the HVF and mfVEP probability plots, a hemifield was classified as abnormal if three or more contiguous points were significant at less than 5%, with at least one at less than 1%. RESULTS: Of the 200 hemifields tested (50 patients x two eyes x two hemifields), 75 showed significant clusters on the HVF, and 74 (monocular probability plot) and 93 (monocular or interocular plot) showed significant clusters on the mfVEP. Overall, the HVF and mfVEP results agreed on 74% of the hemifields, and 90 hemifields were normal and 58 were abnormal on both the mfVEP (interocular and/or monocular abnormal) and HVF cluster tests. Of the 52 disagreements, 35 hemifields had a significant cluster on the mfVEP, but not on the HVF, whereas the reverse was true of 17 hemifields. A case-by-case analysis indicated that misses and false-positive results occurred on both the HVF and mfVEP tests. CONCLUSIONS: As predicted from a theoretical analysis, under these conditions (i.e., the signal-to-noise level) the HVF and monocular mfVEP tests showed a comparable number of defects, and, with the addition of the interocular test, the mfVEP showed more abnormalities than the HVF. However, although there were abnormalities detected by the mfVEP that were missed by the HVF, the reverse was true as well.

Adult↗

PubMed2004

The wing 2 region of the FOXC1 forkhead domain is necessary for normal DNA-binding and transactivation functions.

PURPOSE: To determine the biochemical defects that underlie Axenfeld-Rieger malformations, to determine a functional role for wing 2 in FOXC1, and to understand how mutations in this region disrupt FOXC1 function. METHODS: Sequencing DNA from patients with Axenfeld-Rieger malformation resulted in the identification of two novel missense mutations (G165R and R169P) in wing 2 of FOXC1. Site-directed mutagenesis was used to introduce these mutations, as well as previously reported mutation (M161K), into the FOXC1 cDNA. These FOXC1 mutants were evaluated to determine their ability to localize to the nucleus, bind DNA and activate gene expression. RESULTS: Two novel missense mutations were identified in unrelated patients, in wing 2 of the FOXC1 forkhead domain. Because there had been no previous biochemical analysis, the mutation M161K was also investigated. All three mutant proteins localized correctly to the nucleus. The G165R mutation maintained wild-type levels of DNA binding; however, both the M161K and R169P mutations displayed reduced DNA binding ability. Biochemical analysis showed that all three mutations disrupt FOXC1's transactivation ability. CONCLUSIONS: Biochemical analysis of mutations G165R and R169P and of a previously reported mutation, M161K, demonstrate the functional significance of wing 2. M161K and R169P disrupt DNA binding of FOXC1, consistent with the hypothesis that wing 2 is necessary for DNA binding. The results also suggest that wing 2 plays a role in gene activation. These results provide the first insights into how mutations in wing 2 disrupt FOXC1 function.

Amino Acid Sequence↗

PubMed2003

High-frequency ultrasonographic evaluation of conjunctival intraepithelial neoplasia and squamous cell carcinoma.

OBJECTIVE: To evaluate the high-frequency B-scan ultrasonographic characteristics of squamous conjunctival neoplasia (conjunctival intraepithelial neoplasia and squamous cell carcinoma). METHODS: Each of 11 patients was examined with 20- and/or 50-MHz ultrasonography in a retrospective consecutive case series. MAIN OUTCOME MEASURES: Ultrasonographic findings with clinical and histopathologic correlations. RESULTS: Eleven eyes of 11 patients (8 men) were affected. Disease involved the right eye in 6 (55%) of the patients and the left eye in 5 (45%) of the patients; it was multifocal in 5 (45%) of the eyes. All tumors extended to, or primarily involved, the limbal conjunctiva. One patient developed superficial spread overlying a functioning partial-thickness filtering bleb, 1 developed intraocular extension, 1 developed scleral invasion, and 3 developed orbital involvement before treatment. Results of ultrasonographic examinations showed that the superficial aspect of the smaller limbal tumors appeared as fusiform thickening of the conjunctiva. In all patients, the tumor surface was highly reflective in contrast to the characteristically low reflectivity seen within the tumor stroma. Intraocular tumor extension was variably reflective, but evidenced by blunting of the anterior chamber angle and thickening of the uvea. Orbital extension was viewed as low reflective tumor extension into the relatively hyperechoic orbital tissues. CONCLUSIONS: High-frequency ultrasonography may be used to assess the extent of squamous conjunctival neoplasia. While the 50-MHz system offered better resolution, 20-MHz ultrasonography allowed for a wider and deeper field of view. High-frequency ultrasonography was useful in determining tumor thickness, shape, and internal reflectivity, and especially in revealing tumor extension into the sclera, eye, and orbit.

Carcinoma in Situ↗

PubMed2003

Iridociliary apposition in plateau iris syndrome persists after cataract extraction.

PURPOSE: To evaluate the ultrasound biomicroscopic appearance of the anterior segment before and after cataract extraction in eyes with plateau iris syndrome and to determine the effect of postoperative zonular relaxation on ciliary body position. DESIGN: Interventional case series. METHODS: Eyes with plateau iris syndrome scanned before and after cataract extraction between January 1994 and September 2001 were enrolled. The iridociliary relationship and the anterior chamber depth at a distance of 3 mm from the scleral spur were assessed. RESULTS: We examined six eyes of six patients. Mean patient age was 74.2 +/- 6.4 years (standard deviation [SD]) (range, 65-81 years). Mean refractive error was + 1.0 +/- 3.9 diopters [D] (range, -5.75-+5.50), and mean axial length was 21.85 +/- 0.77 mm (range, 20.90-22.95 mm). All eyes had undergone laser iridotomy and argon laser peripheral iridoplasty before cataract extraction. Ultrasound biomicroscopy examination revealed a narrow angle and absence of a ciliary body sulcus in all eyes with focal areas of iridotrabecular apposition in three eyes. Following cataract extraction, the anterior chamber depth increased (P =.0006, paired t test), while the iridociliary contact remained unchanged. CONCLUSIONS: Iridociliary apposition persists after cataract extraction in plateau iris syndrome. Whether the cause is congenital or acquired, or both, remains to be determined.

Aged↗

PubMed2003

An improved technique of eye drop self-administration for patients with limited vision.

PURPOSE: To describe a new, highly accurate, tactile technique to increase accuracy in the self-administration of eye drops. DESIGN: Interventional case series. METHODS: Ten adult patients with loss of fixation (< or = 20/400) in one eye and ten adult patients with loss of fixation in both eyes instilled one drop of artificial tears in each eye using the technique normally employed at home. The time required to instill each drop, the number of drops squeezed from the bottle, and location of the drops' landing points on the face or eye were recorded. The patients were then instructed in a new technique for instillation, guided through the procedure once, and allowed to practice until comfortable with it. All measurements were then repeated. RESULTS: In patients with loss of fixation in one eye, an additional 3.2 +/- 4.1 seconds were required to instill a drop using the new technique (P <.0001, paired t test; range, -7-18 seconds). The mean number of drops dispensed decreased by 0.1 +/- 0.6 drops (P =.60, paired t test; range, -2-1 drop). The accuracy of drop placement increased from 80.0% to 82.5% (P =.32, paired t test). In subjects with loss of fixation in both eyes, using the new technique increased the time needed to instill a drop by 3.8 +/- 3.8 seconds (P <.0001, paired t test; range, -3-13 seconds). The average number of drops dispensed decreased by 0.1 +/- 0.6 drops (P =.25, paired t test; range, -2-1 drop). The accuracy of placement increased from 63.0% to 85.0% (P =.001, paired t test). CONCLUSIONS: This technique of drop instillation may be beneficial for patients with significant visual impairment in both eyes.

Adult↗

PubMed2003

Plasma homocysteine is elevated in patients with exfoliation syndrome.

PURPOSE: To compare plasma homocysteine concentrations among patients with exfoliation syndrome, exfoliative glaucoma, normal-tension glaucoma, and normal control subjects without vascular or inflammatory ocular disease or glaucoma. DESIGN: Cross-sectional study. METHODS: We tested 25 patients with exfoliation syndrome, 50 with exfoliative glaucoma, 25 with normal-tension glaucoma, and 24 control subjects. Fasting plasma homocysteine concentrations were measured by fluorescence polarization immunoassay. Patients using vitamin supplements or medications known to alter serum homocysteine were excluded. RESULTS: Homocysteine levels were higher in both exfoliatin groups compared with controls (exfoliation syndrome: P =.003; exfoliative glaucoma: P =.009); levels in normal-tension glaucoma were higher than but not significantly different from those in controls (P =.2). Hyperhomocysteinemia was present in 16 of 25 (64%) exfoliation syndrome patients, 28 of 50 (56%) exfoliative glaucoma patients, 13 of 25 (52%) normal-tension glaucoma patients, and 7 of 24 (29.2%) controls (P =.005). Multiple logistic regression analyses comparing exfoliation syndrome and exfoliative glaucoma patients with controls indicated that elevated plasma homocysteine concentration was a significant risk factor for exfoliation syndrome, in both those patients (odds ratios per 1.0 micromol/l increase in plasma homocysteine concentrations = 1.47; 95% confidence interval [CI] = 1.08-2.0) and in exfoliative glaucoma patients (odds ratio = 1.3; 95% CI = 1.07-1.6). Although exfoliative glaucoma and normal-tension glaucoma patients were not significantly different with respect to hyperhomocysteinemia, logistic regression modeling of exfoliative glaucoma vs normal-tension glaucoma patients showed that an increased homocysteine concentration was a significant risk factor for exfoliation syndrome in the presence of glaucoma (odds ratio per 1.0 micromol/l increase in homocysteine = 1.2, 95% CI = 1.0-1.4). These relationships were not affected by adjustment for potential confounding due to sex, history of hypertension, or other factors. RESULTS: Elevated plasma homocysteine, a risk factor for cardiovascular disease, is more common in exfoliation syndrome and exfoliative glaucoma patients than healthy controls. Patients with exfoliation syndrome may benefit from measurement of homocysteine levels.

Aged↗

PubMed2003

Multifocal visual evoked potential responses in glaucoma patients with unilateral hemifield defects.

PURPOSE: To determine whether the multifocal visual evoked potential (mfVEP) technique can detect damage to the visual system in the unaffected hemifields of patients with glaucoma and unilateral hemifield defects. DESIGN: Experimental study. METHODS: Monocular mfVEPs and achromatic automated perimetry (AAP) were obtained in both eyes of 16 patients with open-angle glaucoma and unilateral hemifield defects. The mfVEPs were obtained using a pattern-reversal dartboard array with 60 sectors; the entire display was 44.5 degrees in diameter. For each pair of mfVEP responses an interocular ratio of root-mean-square amplitude was calculated. These values were compared with the mean values obtained from 30 control subjects. Probability plots for MfVEP were derived. A cluster analysis was used to determine whether an mfVEP hemifield was normal or abnormal. RESULTS: Three of 60 (5.0%) mfVEP hemifields from control subjects had significant mfVEP deficits based upon a cluster of abnormal points. Significant mfVEP deficits were detected in the affected AAP hemifield in 15 of 16 (93.8%) glaucoma patients and in 6 of 16 patients in hemifields with apparently normal AAP. The percentage of hemifields with abnormal mfVEPs, but normal AAP, was significantly higher for the glaucoma patients than for the controls (37.5% vs 5.0%, P <.001, chi square).In glaucomatous eyes with achromatic visual fields defects limited to one hemifield, the mfVEP technique can detect evidence of glaucomatous damage in the unaffected hemifield.

Adult↗

PubMed2003

Long anterior zonules and pigment dispersion.

PURPOSE: To describe pigment dispersion associated with long anterior zonules. DESIGN: Multicenter observational case series. METHODS: Fifteen patients, seven of whom were treated for glaucoma or ocular hypertension, were identified with long anterior zonules and pigment dispersion. Transmission electron microscopy was performed on one anterior capsule specimen. RESULTS: All patients had anterior zonules that inserted centrally on the lens capsule. Signs of pigment dispersion included corneal endothelial pigmentation, loss of the pupillary ruff, and variable trabecular meshwork pigmentation. Ultrasound biomicroscopy verified the lack of posterior iris insertion and concavity. There was no exfoliation material. Transmission electron microscopy showed zonular lamellae with adherent pigment granules, and no exfoliation material. CONCLUSIONS: Long anterior zonules inserted onto the central lens capsule may cause mechanical disruption of the pigment epithelium at the pupillary ruff and central iris leading to pigment dispersion.

Adult↗