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Biomedical subjects

M B Shields

Publications and source records attributed to M B Shields.

At least 91 records · Page 5Linked to original sources
PubMed1989

A comparison of the clinical variations of the iridocorneal endothelial syndrome.

Iridocorneal endothelial syndrome is generally considered to have three major variations: Chandler's syndrome, progressive (essential) iris atrophy, and the Cogan-Reese syndrome. To better understand the clinical significance of this classification, we studied the medical records of 37 consecutive patients from our practice, comparing the presentation and course of the three subgroups. Chandler's syndrome was the most common clinical variant within this spectrum of disease (21 cases). Patients with Chandler's syndrome had more severe corneal edema than the rest of the group, while those with progressive iris atrophy (8 cases) or the Cogan-Reese syndrome (8 cases) had worse secondary glaucoma.

Adult↗
PubMed1989

Reproducibility of pallor measurements with the optic nerve head analyzer.

One eye each of ten healthy volunteers was tested with the Rodenstock Optic Nerve Head Analyzer on ten separate occasions. A color-coded pallor map was developed for each examination. A color transparency of each pallor map was then obtained from the television monitor of the Optic Nerve Head Analyzer, using a camera mounted on a tripod at a fixed distance from the screen. A color-coded zone within the center of the disc was chosen for each set of ten studies, and the area of this zone was measured by boundary analysis with another computerized image analyzer, the Oasys Image Processor. There was wide intrasubject variation in all ten volunteers, suggesting that the pallor map generated by the Optic Nerve Head Analyzer, when used in the manner described in this paper, is not adequate for following subtle changes in optic nerve head pallor.

Humans↗
PubMed1989

Full threshold versus quantification of defects for visual field testing in glaucoma.

Nineteen glaucoma patients, 17 ocular hypertensives, and 16 normal subjects underwent visual field testing on the Humphrey Field Analyzer using two programs: full threshold (thresholding of all test points with double-crossing technique) and quantification of defects (thresholding only points that deviated more than 6 dB from a presumed normal retinal contour). The purpose of the study was to compare the diagnostic value of information gained by the latter, less time-consuming test with that of the full threshold procedure. The average time requirement per eye was 13 min 11 s for full thresholding and 4 min 22 s for quantification of defects. Of the 104 sets of fields, the diagnosis was at variance in 18. The differences were most often due to shallow defects in otherwise normal fields or shallow defects surrounding deeper scotomas that had been detected by both programs. The shallow defects placed the fields in more advanced diagnostic categories and were all detected with the full threshold technique.

Diagnosis, Computer-Assisted↗
PubMed1989

An evaluation of three surgical approaches for coexisting cataract and glaucoma.

Seventy-eight eyes of 69 patients with coexisting cataract and glaucoma underwent extracapsular cataract extraction and posterior chamber intraocular lens implantation by one surgeon. A combined guarded filtering procedure was performed in 22 of these cases, and a two-stage procedure filtering surgery followed by cataract extraction was performed in 22 more. Cataract surgery alone was performed in the remaining 34. Since different criteria were used for selecting one of these three surgical approaches, and since baseline values in the three groups were not comparable, the significance of the results is limited. Observations of possible clinical significance, however, include the following: there were fewer early postoperative intraocular pressure rises associated with the combined procedures than were associated with cataract surgery alone, but there was an otherwise relatively lower complication rate in the latter group. All three groups had similar final intraocular pressures, although eyes undergoing the two-stage procedure, having had higher baseline pressures than those in the other two groups, had a higher percentage pressure reduction.

Adult↗
PubMed1988

Management of anterior chamber depth after trabeculectomy.

We followed up 36 eyes of 34 patients for the first three months after trabeculectomy, paying special attention to the depth of the anterior chamber. A significant difference in postoperative course was noted between those eyes with central cornea-lens touch and those with cornea-iris touch but not contact between cornea and lens. The former group (four eyes) had a high rate of complications, including corneal edema, cataract, and bleb failure, despite early efforts to reform the anterior chamber. The latter group (18 eyes), in which the anterior chambers were all allowed to reform spontaneously, had a favorable course, similar to those eyes that maintained formed anterior chambers throughout the study.

Adult↗
PubMed1988

Peripheral visual field testing by automated kinetic perimetry in glaucoma.

The peripheral visual field was measured with a single kinetic target and the central 30 degrees with static stimuli in 600 eyes of 323 patients with glaucoma and patients suspected of having glaucoma using an automated perimeter (Fieldmaster 5000). The purpose of the study was to compare the additional information gained by the peripheral field testing against the time requirement for this extra procedure. An abnormal peripheral field supported the diagnosis suggested by a central abnormality in 131 eyes (21.8%), while a defect in the peripheral field provided the principal diagnostic information, when the central field was normal or equivocal, in 25 cases (4.2%). Peripheral field measurements accounted for approximately 28% of the total testing time.

Glaucoma↗
PubMed1988

Exfoliation syndrome. Prevalence in a southeastern United States population.

A prospective study of 2121 patients in the southeastern United States having no evidence of glaucoma, suspected of having primary open angle glaucoma, having primary open angle glaucoma, or having open angle glaucoma with exfoliation syndrome revealed an overall prevalence of exfoliation syndrome of 1.6% and a prevalence in the glaucoma subpopulation of 6.0%. All but one of the 33 patients with exfoliation syndrome were at least 60 years of age, and the prevalence of exfoliation syndrome in the subgroup of 1000 patients in this age group was 3.2%. Among the patients in this age group who did not have open angle glaucoma, 1.6% had exfoliation syndrome, and this prevalence was significantly less than those reported in studies from other geographic areas.

Adult↗
PubMed1988

Transscleral neodymium-YAG cyclophotocoagulation. A histologic study of human autopsy eyes.

Transscleral cyclophotocoagulation was performed with a neodymium-YAG laser in the free-running mode (20-ms pulses) on eight human autopsy eyes. Variables studied were laser beam position and angle, defocusing, and pulse energy. Based on gross and histologic evaluation of the treated eyes, a tangential beam placed 1.0 to 1.5 mm behind the limbus, with maximum defocusing and an energy setting of approximately 8 J, appears to provide the optimum probability of damaging the ciliary processes.

Ciliary Body↗
PubMed1988

Exfoliation syndrome in the southeastern United States. I. Prevalence in open-angle glaucoma and non-glaucoma populations.

A prospective study of 2,121 patients, 30 years of age or older, examined in two clinics in the southeastern United States with dilated slit-lamp biomicroscopy, revealed the exfoliation syndrome in 1.6% of the total population and in 6.0% of an open-angle glaucoma subpopulation. All but one of the 33 patients with exfoliation syndrome were over age 60 years, and the prevalence of exfoliation syndrome in the subgroup over age 60 was 3.2%. Among the patients over age 60 who did not have open-angle glaucoma, 1.6% had exfoliation syndrome. By chi square analysis, the prevalence of the exfoliation syndrome in the over age 60 population without glaucoma was found to be significantly less (P = 0.00009) than reported in studies from other geographic areas.

Age Factors↗
PubMed1988

Exfoliation syndrome in the southeastern United States. II. Characteristics of patient population and clinical course.

Fifty-three patients with the exfoliation syndrome, seen at the Duke University Eye Center, Durham, North Carolina, were characterized by a mean age of 71.3 years, a predilection toward women (38:15), and a marked preponderance of whites to blacks (51:2). There were 31 unilateral and 22 bilateral cases on the initial exam, with glaucoma in 62 of the 75 eyes with exfoliation, as well as 15 of the fellow, non-exfoliation eyes. The incidence of glaucoma is undoubtedly skewed, since the patients were from a glaucoma referral practice. Twenty-four patients were followed from six months to ten years, with a mean of three years, during which time four patients progressed from unilateral to bilateral exfoliation and five more patients acquired glaucoma in eyes with the exfoliation syndrome. The glaucoma associated with the exfoliation syndrome was typically difficult to treat with a high percentage of patients requiring multiple medications or surgical intervention.

Age Factors↗
PubMed1988

Intraocular pressure following intravitreal silicone oil injection.

The clinical features of 100 consecutive cases and the histopathology of six enucleated eyes, all having undergone silicone oil injection for complicated retinal detachments, were studied with regard to the incidence and mechanisms of postoperative intraocular pressure changes. Preoperatively, five patients had glaucoma and 35 had hypotony (7 mm Hg or less). Immediately after surgery, 43 patients had glaucoma and 14 had hypotony, while seven had glaucoma and 39 had hypotony in the late postoperative period (average follow-up of 1 year). In most cases, the mechanism of intraocular pressure change did not appear to be directly related to the presence of silicone, but rather to the preoperative status of the eye and other aspects of the vitreoretinal surgery. When silicone was a factor, the resulting intraocular pressure appeared to represent a balance between mechanisms obstructing aqueous outflow (pupillary block and the reaction to silicone bubbles in the anterior chamber angle) and mechanisms reducing aqueous production (cyclitic membranes and retinal detachment).

Adolescent↗
PubMed1988

Transpupillary argon laser cyclophotocoagulation in the treatment of glaucoma.

Twenty-seven patients with glaucoma, which could not be controlled with maximum tolerable medication and standard laser techniques, underwent transpupillary argon laser cyclophotocoagulation. Only six patients (22.3%) had a successful outcome, and the postoperative course in many cases was complicated by an additional, sustained increase in intraocular pressure. Notwithstanding these results, the procedure may be useful occasionally to preclude the need for conventional glaucoma surgery.

Adolescent↗
PubMed1988

The early postoperative pressure course in glaucoma patients following cataract surgery.

The intraocular pressure (IOP) course during the first 2 months after cataract surgery in patients with preexisting glaucoma was evaluated in 25 consecutive cases of extracapsular cataract extraction (ECCE) with posterior chamber intraocular lens (PC-IOL) implantation and in 25 cases of intracapsular cataract extraction (ICCE) without IOL implantation. Although the former group had a slightly more favorable postoperative IOP course, approximately half of each group had a pressure rise above 21 mm Hg on the first day postoperatively, and approximately 80% had an IOP rise during the first postoperative month. These findings support the position that all glaucoma patients require close monitoring of their IOPs immediately after both ECCE and ICCE, and that patients with moderate to advanced glaucomatous damage should probably have glaucoma surgery either before or in combination with their cataract operation.

Adult↗
PubMed1987

Reproducibility of topographic measurements with the optic nerve head analyzer.

We evaluated the reproducibility of optic nerve head contour mapping by the Optic Nerve Head Analyzer with ten recordings and analyses of one eye each in ten normal volunteers and ten analyses of a single recording in three of the eyes. Reproducibility was good for cup-to-disk ratio and neural rim area. Reproducibility was poor for cup volume, which was inversely related to cup size. Instrument and operator error were low for cup-to-disk ratio and neural rim area, but high for cup volume. Subjective comparisons of contour lines from five recordings of six eyes implied good reproducibility of this measurement.

Glaucoma↗
PubMed1987

Suprachoroidal hemorrhage after glaucoma filtering surgery.

We reviewed a series of 305 consecutive glaucoma filtering procedures performed by one surgeon. Five eyes (1.6%) had a postoperative suprachoroidal hemorrhage. All five eyes were aphakic, and four had undergone a partial or complete vitrectomy before the glaucoma surgery. The incidence of this complication was 13% (five of 37) among the aphakic eyes and 33% (four of 12) in the aphakic, vitrectomized eyes in this series. Despite drainage of the hemorrhage and reformation of the anterior chamber, three patients had a poor visual outcome.

Adult↗