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Biomedical subjects

D H Nicholson

Publications and source records attributed to D H Nicholson.

At least 19 recordsLinked to original sources
PubMed1991

Results and complications in treated retinal breaks.

One hundred sixty-four patients (171 eyes) were treated for retinal breaks and the treatment outcomes were studied. One hundred two eyes were acutely symptomatic, 22 eyes were chronically symptomatic, and 47 eyes were asymptomatic. The reasons for further treatment in 38 of the 171 eyes (22%) included the following: (1) inadequate closure of the original break without detachment in eight eyes (5%), (2) new breaks without detachment in 15 eyes (9%), (3) an operation for retinal detachment caused by the original break in seven eyes (4%), or (4) retinal detachment caused by a new break in eight eyes (5%). Failure rates of treatment among acutely symptomatic, chronically symptomatic, and asymptomatic subgroups were not statistically significant. The risk of treatment failure was higher for aphakic and pseudophakic eyes, and in eyes with peripheral retinal abnormalities in the fellow eye. Among 38 patients with failed treatments, 20 (52%) returned for further examination within one month of initial treatment, whereas eight of the 38 patients with failed treatments (21%) returned six months or more after initial treatment. Peripheral retinal abnormalities were recognized initially in 65 of the 171 fellow eyes (38%) and subsequently developed in nine of the fellow eyes (5%) during the follow-up interval. Further treatment is often necessary after initial treatment of peripheral retinal breaks, emphasizing the need for careful long-term follow-up care.

Acute Disease↗
PubMed1991

Choroidal detachment associated with malignant choroidal tumors.

The association of choroidal detachment with malignant choroidal tumors is not well recognized. The authors' experience with six cases suggests that choroidal detachment may be associated with both metastatic tumors and choroidal melanoma. In two of these cases, the choroidal or retinal detachment was so massive that echography was necessary to detect the underlying tumor. Three patients presented with painful visual loss, and three patients presented with painless visual loss or a visual field defect. In one patient, the correct diagnosis and appropriate treatment of the choroidal metastasis with external radiation relieved the patient's pain and improved visual acuity from 1/200 to 20/35. Metastatic and primary uveal malignant tumors should be added to the list of causes of choroidal detachment and can be excluded only after thorough clinical, and often echographic, examination.

Aged↗
PubMed1990

Ophthalmology.

Explore the source record for details and available documents.

Cataract↗
PubMed1990

Subretinal hemorrhage management by pars plana vitrectomy and internal drainage.

We reviewed 14 consecutive cases of subretinal hemorrhage involving the macula, in which surgery to remove the hemorrhage was performed by the authors between February 1984 and January 1989. All patients underwent pars plana vitrectomy and internal subretinal hemorrhage drainage. The causes of subretinal hemorrhages in group 1 were primary rhegmatogenous retinal detachments (three eyes), complications from scleral buckling procedures (three eyes), traumatic retinal detachments (two eyes), and sickle cell retinopathy associated with anticoagulation therapy after a pulmonary embolus (one eye). Group 2 consisted of five eyes with massive subretinal hemorrhage associated with age-related macular degeneration. In group 1, recurrent postoperative retinal detachment occurred in five eyes but reattachment was achieved in eight of the nine eyes, and final visual acuities were 20/400 or better in those eight eyes. In group 2, marked subretinal fibrosis occurred in two eyes. Although three eyes had improved visual acuities, final visual acuities were 5/200 or worse in all five eyes.

Drainage↗
PubMed1989

MR technique for localization and verification procedures in episcleral brachytherapy.

Spatial definition of an intraocular tumor and subsequent determination of the actual position of an implanted eye plaque are essential for adequate ocular brachytherapy treatment planning. However, a method for verification of the plaque placement which would provide required 3-dimensional information is not available at present. In addition, tumor localization procedures, including ultrasonography and CT techniques, cannot always offer the precision needed for 3-dimensional definition of an intraocular target. This communication describes a magnetic resonance imaging technique specifically developed for both localization and verification procedures. A 1.5 Tesla magnetic resonance scanner, spin-echo pulse sequence (echo time 30 msec, repetition time 700 msec), and commercially available surface coil were used to obtain a series of transverse, coronal, and sagittal images of a slice thickness of 3 mm. Usually, eight scans in each of the three planes were needed for adequate coverage of the orbit. The required patient set-up and data acquisition time did not exceed 40 minutes. With a data matrix size of 256 X 256 pixels and 13 cm field of view, localization and verification were accomplished with a precision of 0.5 mm. Our results suggest that the magnetic resonance imaging technique permits precise integration of diagnostic and therapeutic procedures, and in addition provides adequate data for accurate treatment planning. We conclude that magnetic resonance imaging is the preferred diagnostic technique for episcleral brachytherapy.

Brachytherapy↗
PubMed1986

Rhegmatogenous retinal detachment in angiomatosis retinae.

Three patients with von Hippel tumors of the retina developed rhegmatogenous retinal detachments caused by surface traction on the angioma. The break in each case was located at the posterior base of the angioma, between the afferent and efferent vessels. Conventional scleral buckling surgery with cryotherapy and a silicone episcleral sponge successfully reattached the retina in all three cases.

Adolescent↗
PubMed1985

Echographic and histologic tumor height measurements in uveal melanoma.

We studied the relation between echographic tumor elevation (measured by standardized A-scan echography) and histologic tumor thickness (measured from histologic slides with an ocular micrometer) in a series of 53 choroidal and ciliary body melanomas enucleated within one month of the most recent echographic measurement. Histologic height was less than echographic height for all sizes and locations studied, with a correlation coefficient of r = .926. The following equations for straight lines described the relationship: Echographic height = 1.964 + (1.042 X histologic height). Histologic height = -0.660 + (0.823 X echographic height). Thus, current thickness criteria for small (less than 3 mm), medium (3 to 5 mm), and large (more than 5 mm) melanomas, based on histologic measurements, may be translated to the following echographic terms: small, less than 5.2 mm; medium, 5.2 to 7.2 mm; and large, more than 7.2 mm. The source of this difference is a variable degree of tumor shrinkage induced by fixation and histologic preparation.

Choroid↗
PubMed1978

Epibulbar Kaposi sarcoma.

This report illustrates the clinical and pathological features of epibulbar Kaposi sarcoma in an adult who had no other cutaneous or systemic manifestations of the disorder.

Aged↗
PubMed1978

Small melanomas of the choroid.

We reviewed 38 cases of small choroidal melanomas on file in the Eye Pathology Laboratory of Bascom Palmer Eye Institute, Miami. Clinical and histopathological features of these cases were noted, and clinical follow-up information was obtained for 36 (95%) of the patients. Two tumor deaths occurred among the 18 patients that had a possible follow-up period of six years of more, yielding a tumor death rate of 11%. Retrospective analysis of clinical records and photographs permitted us to correlate the presence or absence of documented tumor growth with the degree of mitotic activity.

Adolescent↗
PubMed1977

Intraocular extension of squamous cell carcinoma of the conjunctiva.

The present case report illustrates the clinical and pathologic features of intraocular invasion by squamous cell carcinoma of the conjunctiva. Cytologic study of aqueous humor aspirate is a useful technique for confirming the diagnosis of this unusual route of tumor extension.

Aged↗
PubMed1977

A clinical and histopathological study of François-Neetens speckled corneal dystrophy.

A 57-year-old black man had François-Neetens speckled dystrophy of the cornea and orbital phycomycosis. Examination of family members confirmed an auto-somal-dominant pattern of inheritance. Light and electron microscopic study of the cornea of a blind eye disclosed that the corneal opacities were represented by swollen, vacuolated keratocytes filled with histochemically demonstrable acid mucopolysaccharide and complex lipids. Thus, this dystrophy may represent a dominantly inherited metabolic disorder confined to the cornea.

Adolescent↗
PubMed1976

Ocular toxoplasmosis in an adult receiving long-term corticosteroid therapy.

Sudden death of a 58-year-old woman who developed ocular toxoplasmosis while receiving long-term systemic corticosteroid therapy permitted correlation of early histopathologic lesions with their clinical counterpart recorded on fundus photographs. A wide-spread, paravascular, whitish, retinal opacification dominated the initial clinical picture. These lesions were represented histologically by focal zones of inner retinal necrosis located adjacent to arteries and veins. No associated inflammatory cell infiltrate was present, and numerous viable free Toxoplasma organisms were consistently present at the interface between necrotic and healthy retina. Electron microscopy of formaldehyde-fixed tissue provided a useful technique for confirming the identity of the infecting organism in the absence of serologic or culture data.

Adrenal Cortex Hormones↗