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Biomedical subjects

G E Trope

Publications and source records attributed to G E Trope.

At least 19 recordsLinked to original sources
PubMed1998

Ultrasound biomicroscopy in Sturge-Weber-associated glaucoma.

PURPOSE: To evaluate Sturge-Weber-associated glaucoma using ultrasound biomicroscopy. METHOD: Case report. Clinical examination combined with ultrasound biomicroscopy was performed in a patient with Sturge-Weber-associated glaucoma. RESULTS: In the patient's left eye, which had Sturge-Weber-associated glaucoma, a 360-degree supraciliary effusion, dilated superficial and intrascleral vessels, and an open angle were detected by ultrasound biomicroscopy. CONCLUSION: The presence of dilated intrascleral vessels and supraciliary fluid support the hypothesis of increased episcleral venous pressure as the cause of elevated intraocular pressure in this syndrome.

Adolescent↗
PubMed1997

Pointwise univariate linear regression of perimetric sensitivity against follow-up time in glaucoma.

PURPOSE: The authors compared pointwise univariate linear regression (ULR) of sensitivity against follow-up as an indicator of visual field progression with that of the corresponding ULR of mean deviation (MD) and with the Glaucoma Change Probability (GCP) analysis. The authors determined the influence of the number and sequence of prior examinations on the slope of the pointwise function. METHODS: Univariate linear regression was undertaken at each stimulus location on the arbitrarily assigned left eyes of 38 patients with glaucoma examined with the Humphrey Field Analyzer Programs 30-2 or 24-2 (stimulus size III, Humphrey Instruments Inc, San Leandro, CA). The mean age was 59.0 years (standard deviation [SD] = 12.9), the mean number of fields per patients was 12.0 (SD = 2.8), and the mean duration of follow-up was 6.0 years (SD = 1.6). RESULTS: Four patients showed statistically significant MD slopes. Of the 34 patients exhibiting a nonsignificant MD slope, 15 exhibited clusters of at least two contiguous progressing locations. Less than half of these locations were designated as progressing by GCP. The GCP detected less than one third of the locations considered progressing by ULR for the last six fields in the series: this was attributed to the nonlinear nature of the decline in sensitivity. CONCLUSIONS: The degree of agreement between the outcomes of ULR and GCP was dependent on the quality of the collected data, the magnitude of the baseline sensitivity, the extent and type of the subsequent visual field progression, and the position of the fields within the examination series. Good agreement was illustrated at those locations where the deterioration fell outside the limits of expected variability in stable glaucoma.

Female↗
PubMed1997

Laser scanning tomography of the optic nerve head in ocular hypertension and glaucoma.

BACKGROUND: This study evaluated the ability of laser scanning tomography to distinguish between normal and glaucomatous optic nerve heads, and between glaucomatous subjects with and without field loss. METHODS: 57 subjects were classified into three diagnostic groups: subjects with elevated intraocular pressure, normal optic nerve heads, and normal visual fields (n = 10); subjects with glaucomatous optic neuropathy and normal visual fields (n = 30); and subjects with glaucomatous optic neuropathy and repeatable visual field abnormality (n = 17). Three 10 degrees image series were acquired on each subject using the Heidelberg retina tomograph (HRT). From the 14 HRT stereometric variables, three were selected a priori for evaluation: (1) volume above reference (neuroretinal rim volume), (2) third moment in contour (cup shape), and (3) height variation contour (variation in relative nerve fibre layer height at the disc margin). Data were analysed using analysis of covariance, with age as the covariate. RESULTS: Volume above reference, third moment in contour, and mean height contour were significantly different between each of the three diagnostic groups (p < 0.001). Height variation contour showed no significant difference among the three diagnostic groups (p = 0.906). CONCLUSIONS: The HRT variables measuring rim volume, cup shape, and mean nerve fibre layer height distinguished between (1) subjects with elevated intraocular pressures and normal nerve heads, and glaucomatous optic nerve heads, and (2) glaucomatous optic nerve heads with and without repeatable visual field abnormality. This study did not directly assess the ability of the HRT to identify patients at risk of developing glaucoma. It is hypothesised that the greatest potential benefit of laser scanning tomography will be in the documentation of change within an individual over time.

Adult↗
PubMed1996

Glaucoma laser suture lysis.

AIM: Suture lysis is commonly performed after trabeculectomy to improve bleb function. It is often thought to be an innocuous procedure. This is the first large study to determine the safety of the procedure and compare results with a control group. METHODS: Two hundred successive trabeculectomies performed between January 1992 and October 1993 were analysed. RESULTS: Ninety nine eyes underwent trabeculectomy and suture lysis; 101 eyes underwent trabeculectomy and did not require postoperative suture lysis. The following complications were noted with suture lysis: flat chambers (13.1%), external aqueous leaks (9%), malignant glaucoma (2%), iris incarceration (2%), and large blebs (2%). All resolved with appropriate management. There was no significant difference in the final postoperative mean pressures between the lysis and the non-lysis groups. CONCLUSION: Suture lysis is not an innocuous procedure. However if managed appropriately, complications do not affect the intraocular pressure outcome.

Eye Injuries↗
PubMed1996

Loss of sensitivity to motion-defined form in patients with primary open-angle glaucoma and ocular hypertension.

During the past few years many researchers have attempted to find a psychophysical test that will identify at an early stage patients at risk for developing glaucoma. We investigated the ability of a test of motion-defined (MD) form recognition to discriminate between patients with primary open-angle glaucoma (POAG) and control subjects and to identify patients with ocular hypertension (OHT) at risk for developing glaucoma. Performance on two MD tests and three tests of static, luminance-defined (LD) form recognition was compared. Speed thresholds for reading MD letters proved to be the most sensitive test of early glaucomatous damage. 80% of POAG and 38% of OHT patients were abnormal on this test. During a 3-year follow-up period, 50% of these OHT patients developed glaucoma. These psychophysical findings support the hypothesis of early motion deficits in glaucoma.

Adult↗
PubMed1996

Accommodation and iridotomy in the pigment dispersion syndrome.

BACKGROUND AND OBJECTIVE: Iris concavity has been noted in pigment dispersion syndrome, and could have a role in producing iris-zonule contact. Iris concavity is most likely caused by a relative increase in anterior chamber pressure. The method by which this occurs remains speculative. The authors used ultrasound biomicroscopy to examine the role of accommodation in producing iris concavity and to document changes that occur following iridotomy. PATIENTS AND METHODS: Thirteen patients with clinically diagnosed pigmentary dispersion and pigmentary glaucoma underwent accommodation studies while being continuously imaged with ultrasound biomicroscopy. Anterior chamber depths were measured and iris configuration noted on distance and near fixation. These studies were repeated in 6 patients following laser iridotomy. RESULTS: All patients showed a decrease in anterior chamber depth with accommodation. Ten patients had a planar iris configuration on distance fixation and 3 concave. Eleven of 13 patients showed increased concavity of the iris on near fixation as compared with distance fixation. Following iridotomy in 6 patients, the iris showed a planar configuration that remained unchanged on near fixation. CONCLUSION: Accommodation increases iris concavity in some patients with pigment dispersion syndrome. The most likely explanation is an accommodation-induced relative increase in anterior chamber pressure secondary to anterior movement of the lens surface. Iridotomy prevents change in the iris profile with accommodation.

Accommodation, Ocular↗
PubMed1995

Ultrasound biomicroscopic imaging of the effects of YAG laser cycloablation in postmortem eyes and living patients.

PURPOSE: The authors performed a series of experiments designed to determine if early effects of YAG laser cycloablation could be detected by ultrasound biomicroscopy in postmortem eyes and living patients. They also designed an apparatus that allowed simultaneous ultrasound biomicroscopic imaging of YAG laser cycloablation. METHODS: Treated and untreated regions of postmortem eyes treated with YAG cycloablation were imaged and compared. Treatment was placed at varying distances from the limbus in postmortem eyes and the resulting effects imaged. Histologic examinations were performed after imaging. Six living patients had ultrasound biomicroscopy before and after YAG cycloablation. An apparatus combining contact YAG laser and ultrasound biomicroscopy was used in postmortem eyes. RESULTS: Early treatment effects imaged included ciliary epithelial disruption, ciliary epithelial separation, and bubble formation. Ultrasound biomicroscopic findings varied with the distance of treatment from the limbus and were maximal below the treatment site. Results of histologic examination showed close correlation to the ultrasound biomicroscopic images. Similar findings to those found in postmortem eyes were found in living patients after treatment. The apparatus combining contact YAG and ultrasound biomicroscopy allowed realtime imaging of effects of YAG laser cycloablation. CONCLUSIONS: The ability of ultrasound biomicroscopy to detect changes associated with cyclodestructive procedures potentially could provide us with a method of improving treatment precision and correlating treatment effect with clinical response.

Cadaver↗
PubMed1995

Ultrasound biomicroscopic features of spherophakia.

BACKGROUND: Spherophakia is an uncommon diagnosis. This is the first case report of spherophakia evaluated by ultrasound biomicroscopy. METHODS: Ultrasound biomicroscopy is a new diagnostic technique developed by one of the authors and provides images with microscopic resolution of the anterior segment. A patient with spherophakia was evaluated by ultrasound biomicroscopy (Zeiss-Humphrey, 50MHz) before and after YAG laser iridotomy. RESULTS: Ultrasound biomicroscopic assessment revealed a shallow anterior chamber, a very steep anterior lens curvature, iridolenticular contact, elongated zonules, and an increased distance between the lens equator and the ciliary processes. Angle closure glaucoma was due to a pupil block mechanism. The pupil block was relieved by YAG laser iridotomy. CONCLUSIONS: Ultrasound biomicroscopy is a useful technique to confirm the diagnosis of spherophakia. The pupil block in spherophakia is relieved by YAG laser iridotomy.

Adult↗
PubMed1995

(-)-Deprenyl increases the survival of rat retinal ganglion cells after optic nerve crush.

Retinal ganglion cells (RGCs) have been shown to die by apoptosis after damage to their axons caused by optic nerve crush and the death can be reduced by some neurotrophic factors. Since (-)-deprenyl can reduce apoptotic death in some neuronal systems, we determined whether it can increase RGC survival after optic nerve crush. Fluoro-Gold (FG), a fluorescent retrograde tracer, was injected into both superior colliculi to pre-label RGC cells bodies in the retinal ganglion cell layers (RGCLs) of adult Sprague-Dawley rats. Fours days later, the left optic nerve was crushed immediately behind the globe and the animals received either (-)-deprenyl (1 mg/kg) or saline by intraperitoneal injection every two days for 14 days. Nissl stained neuronal cell bodies per mm of section length of RGCL were counted from serial frozen sections. The number of RGCL cell bodies sending axons to the superior colliculi (RGCSCS) were identified by FG fluorescence as a means of determining the proportion of RGCL neurons (RGCLns) that were RGCSCS. In the uncrushed retinas an average of 40.7% of the RGCLns were found to be RGCSCS. There was no difference in RGCSCS/mm between the uncrushed treated with saline group and the uncrushed group treated with (-)-deprenyl group. The optic nerve crush with saline group showed a decrease in RGCSCS to 3.0 +/- 1.0% of the uncrushed saline group while the optic nerve crush with (-)-deprenyl group showed a considerably smaller decrease in RGCSCS to 36.9 +/- 11.2% of the uncrushed saline group.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1995

A common gene for juvenile and adult-onset primary open-angle glaucomas confined on chromosome 1q.

Primary open-angle glaucoma (POAG), which causes progressive loss of the visual fields, was subdivided into two groups according to age at onset: (1) chronic open-angle glaucoma (COAG) diagnosed after age 40 years and (2) juvenile open-angle glaucoma (JOAG) diagnosed between 3 years of age and early adulthood. A JOAG gene (GLC1A) was recently mapped to chromosome 1q. We studied 142 members of a huge multigenerational French Canadian family affected with autosomal dominant POAG. Either JOAG or COAG was diagnosed in 40 patients. Six subjects were also diagnosed with ocular hypertension (OHT), which may lead to POAG. To localize a common disease gene that might be responsible for both glaucoma subsets, we performed linkage analysis considering JOAG and COAG under the same phenotypic category. JOAG/COAG was tightly linked to seven microsatellite markers on chromosome 1q23-q25; a maximum lod score of 6.62 was obtained with AF-M278ye5. To refine the disease locus, we exploited a recombination mapping strategy based on a unique founder effect. The same characteristic haplotype, composed of 14 markers spanning 12 cM between loci D1S196 and D1S212, was recognized in all persons affected by JOAG, COAG, or OHT, but it did not occur in unaffected spouses and in normal family members > 35 years of age, except for three obligatory carriers. Key recombination events confined the disease region within a 9-cM interval between loci D1S445 and D1S416/D1S480. These observations demonstrate that the GLC1A gene is responsible for both adult-onset and juvenile glaucomas and suggest that the JOAG and COAG categories within this family may be part of a clinical continuum artificially divided at age 40 years.

Adolescent↗
PubMed1994

Malignant glaucoma. Clinical and ultrasound biomicroscopic features.

PURPOSE: To determine conditions associated with malignant glaucoma and to assess anterior segment structures in malignant glaucoma using ultrasound biomicroscopy. METHODS: Over a 3-year period, 14 eyes from 14 patients with malignant glaucoma were evaluated. RESULTS: Of the 14 eyes, 7 received medical therapy alone and 7 required both medical and surgical intervention. Predisposing factors included trabeculectomy in 12 eyes, chronic angle-closure glaucoma in 10, sudden ocular decompression in 2 (1 from suture lysis and 1 from corneal perforation), pseudoexfoliation in 4, and cessation of aqueous suppressants and cycloplegics in 2. Ultrasound biomicroscopy of two eyes showed a shallow supraciliary fluid level, anterior rotation of ciliary processes, and obstruction of the trabeculectomy osteum. CONCLUSIONS: Malignant glaucoma is associated with glaucoma surgery, chronic angle-closure glaucoma, pseudoexfoliation, sudden ocular decompression, and cessation of aqueous suppressants. On ultrasound biomicroscopy, a low supraciliary fluid level was found in two patients.

Aged↗
PubMed1994

Deformation of the lamina cribrosa by elevated intraocular pressure.

The purpose of this study was to determine the mechanical response of the lamina cribrosa (LC) to elevated intraocular pressure (IOP) so as to identify possible mechanisms of optic nerve damage in early glaucoma. Ten pairs of normal human eyes were fixed after 24 hours' exposure to 50 mm Hg pressure (experimental eyes) or 5 mm Hg pressure (contralateral control eyes). Photomicrographs of the central region of the optic nerve head (ONH) were taken to examine the LC morphologically and to measure the dimensions of the LC. It was found that elevated IOP caused the LC to deflect posteriorly without affecting its thickness. The majority of the posterior displacement in the LC occurred near the periphery of the ONH. This shape change is consistent with a model of force distribution within the LC in which shear stresses are dominant; such stresses are maximal at the periphery and minimal at the centre of the ONH. These findings support a model in which mechanical forces, specifically shearing stresses within the peripheral lamina, play a direct role in the pathology of glaucomatous optic neuropathy.

Aged↗
PubMed1994

Depot drug delivery system for 5-fluorouracil after filtration surgery in the rabbit.

We investigated the potential value of 50:50 poly (DL glycolic acid-lactic acid) (PGLA) copolymer as a degradable depot delivery system for 5-fluorouracil (5-FU) after filtration surgery. Analysis of retrieved discs after implantation in 22 eyes of 22 pigmented rabbits showed a dual drug release profile and polymer mass loss characteristics. In a second group of pigmented rabbits implantation of PGLA discs impregnated with 5-FU (22 eyes) significantly lengthened the survival time of filtration fistulae compared with discs without 5-FU (18 eyes) or no disc (10 eyes) (p < 0.0001). Use of PGLA copolymer impregnated with 5-FU could prove valuable for patients undergoing glaucoma filtering surgery.

Animals↗
PubMed1994

Ocular timolol levels after drug withdrawal: an experimental model.

Carbon 14-labelled timolol maleate was instilled into both eyes of 12 pigmented rabbits daily for 42 days. Drug levels in the aqueous humour and ocular tissues were measured up to 42 days after drug withdrawal. The results indicate that timolol concentrates mainly in melanotic tissues, with slow release. Even 42 days after withdrawal the drug was still present in pigmented ocular tissues. Timolol was detected in the aqueous up to 5 days after withdrawal. These findings explain the long-term depressant effect of topically administered timolol on aqueous production. We conclude that lower or less frequent doses of timolol should be considered in patients with glaucoma.

Animals↗
PubMed1993

Evaluation of FASTPAC, a new strategy for threshold estimation with the Humphrey Field Analyzer, in a glaucomatous population.

PURPOSE: A new fast strategy for the estimation of threshold, FASTPAC, has been introduced for the Humphrey Field Analyzer. The aim of this study is to evaluate the performance, in a glaucomatous population, of FASTPAC compared with the standard full-threshold 4-2-decibel (dB) double-staircase strategy. METHODS: The sample consisted of 30 glaucoma patients experienced in automated perimetry, ranging in age from 26 to 84 years. One eye of each patient was examined with both strategies using program 24-2, target size III. The order of strategy was randomized for each patient. The results were analyzed using analysis of covariance for a two-period crossover trial. Mean deviation, pattern standard deviation, short-term fluctuation, corrected pattern standard deviation, number of stimulus presentations, and examination time were analyzed separately; test sequence and severity of field loss were considered as between subject factors and age as a covariate. RESULTS: The FASTPAC algorithm demonstrated a 36% saving in examination time (P < 0.001), a lower mean deviation (0.91 dB) (P < 0.001), and a greater short-term fluctuation (0.64 dB) (P = 0.008). The differences in mean deviation (P = 0.015) and short-term fluctuation (P = 0.033) became greater with an increase in age. As the severity of the field loss increased, the short-term fluctuation increased (P = 0.043), and examination time was increased for the FASTPAC strategy, while it became shorter for the standard full-threshold strategy (P = 0.033). CONCLUSIONS: The FASTPAC strategy reduced the examination time but exhibited a decreased estimate of field severity and a greater intra-test variance.

Adult↗
PubMed1993

Prospective study of sub-Tenon's versus retrobulbar anesthesia for inpatient and day-surgery trabeculectomy.

PURPOSE: Several retrospective studies have demonstrated the safety and efficacy of sub-Tenon's anesthesia in ocular surgery. This is the first prospective randomized study comparing sub-Tenon's versus retrobulbar anesthesia for glaucoma surgery. METHODS: Thirty-nine patients undergoing both inpatient and day surgery trabeculectomy were randomized to receive retrobulbar or sub-Tenon's anesthesia. Retrobulbar anesthesia consisted of a 1.5-ml injection of a 1:1 mixture of 2% lidocaine without epinephrine and 0.5% plain bupivacaine with hyaluronidase. Sub-Tenon's anesthesia consisted of 2% lidocaine without epinephrine injected over the superior, medial and lateral recti muscles. Both groups received a van Lint lid block and a standardized sedative. Outcome parameters evaluated included patient demographics, operative complications, intraoperative and postoperative patient comfort, and volume of anesthetic. RESULTS: Seventeen patients were randomized to the retrobulbar group and 22 to the sub-Tenon's group. Patient discomfort was statistically similar between the groups. There was no statistical difference between groups with respect to quantity of sedative received, surgical exposure, eye movements, or operative complications. A retrobulbar hemorrhage, however, developed at the time of retrobulbar anesthesia in one patient, requiring cancellation of surgery. A larger volume of local anesthetic was required in the retrobulbar group versus the sub-Tenon's group (1.8 versus 1.1 ml; P < 0.01). Patients receiving retrobulbar injections were more likely to require additional anesthesia (P < 0.01) and postoperative analgesics (P < 0.05) compared with patients undergoing sub-Tenon's injection. There was no significant difference between the groups with respect to age, sex, or operated eye. CONCLUSIONS: Sub-Tenon's anesthesia is safe and effective for patients undergoing either inpatient or day-surgery trabeculectomies, and it requires less local anesthetic than retrobulbar anesthesia.

Ambulatory Surgical Procedures↗