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Biomedical subjects

A R Irvine

Publications and source records attributed to A R Irvine.

At least 73 records · Page 4Linked to original sources
PubMed1981

Extracapsular cataract extraction and pseudophakos implantation in primates: a clinico-pathologic study.

Eighteen rhesus monkeys underwent lens implantation with Choyce Mark VIII, Binkhorst iridocapsular, or Shearing posterior chamber lenses. They were sacrificed 4-28 months postoperative. The eyes were compared clinically and histologically. Controls included unoperated eyes and eyes with lens extraction without implantation. Several histologic findings pertained equally to cataract extraction with or without lens implantation. Late opacification of the posterior capsule was caused by migrations and fibrous metaplasia of the lens epithelial cells. These cells appeared to undergo such metaplasia only when exposed directly to aqueous, never when they were in firm apposition to another tissue such as another layer of capsular epithelium, lens cortex, or iris. All implants were well tolerated clinically. Histologically the eyes with Binkhorst lenses showed a tendency to focal loss of iris pigment epithelium and some pigmented macrophages in the iris stroma an trabecular mesh. The Choyce lenses frequently displayed marked displacement and thinning of the iris root, and occasionally showed a few chronic inflammatory cells and thin fibrous encapsulation around the implant feet. The Shearing lenses had no effect on the adjacent ciliary body when the loops were well seated in the lens capsule, but when a loop was anterior to the capsule, it eroded into the ciliary body. The loops developed a thin fibrous capsule within the ciliary body with very little chronic inflammatory reaction. The long-term effect of such loops lying in the ciliary body is undetermined, however. At present it is recommended that, if such a lens is implanted, every effort be made to ensure both loops lie in the capsular envelope. On the basis of this study, it is also recommended that in removing such a lens, one must assume that a loop might lie embedded in the ciliary body and cut the lens free from the loops before removing it.

Animals↗
PubMed1981

Old and new techniques combined in the management of intraocular foreign bodies.

A series of patients is presented to illustrate how new techniques are combined with traditional ones in the management of intraocular foreign bodies. Whereas X-ray remains the most sensitive method for detecting metallic foreign bodies and can adequately localize most, ultrasonography and CT scans are shown to be of value in selected cases. Similarly, while magnetic extraction remains the most common method of removal, the techniques developed for pars plana vitrectomy make the use of intraocular forceps relatively safe for those cases unresponsive to the magnet. THe role of vitrectomy in cases with vitreous hemorrhage is discussed.

Adult↗
PubMed1981

Orbital melanoma.

A case of choroidal melanoma metastatic to the contralateral orbit is presented. Ultrasound and orbital computerized tomographic scan data are shown. In patients with a history of choroidal melanoma and a contralateral orbital mass, metastatic orbital melanoma should be suspected.

Aged↗
PubMed1980

Diagnostic modalities in choroidal melanoma.

We prospectively studied 51 patients with choroidal melanomas in a masked manner to determine the accuracy of clinical, ultrasound, and fluorescein diagnosis as well as the accuracy of tumor size measurements. In patients with clear media, clinical diagnosis was the most accurate means of detecting a choroidal melanoma. There was excellent correlation between clinical, ultrasound, and pathology measurements of tumor size. In small melanomas, clinical examination was the most accurate means of measuring tumor diameter and ultrasound the most accurate method of measuring tumor height. Even with a trained ocular oncologist, there was a significant variability in tumor measurements on serial ophthalmoscopic examinations.

Choroid Neoplasms↗
PubMed1980

Retinal emboli in patients with mitral valve prolapse.

Small fibrin-platelet emboli caused by prolapsed mitral valves may cause retinal occlusive disease with a wide range of ophthalmic manifestations, including amaurosis fugax in young people, retinal or choroidal arteriolar occlusion, and retinal neovascularization (atypical Eales' disease). Six patients with retinal occusive disease underwent extensive noninvasive cardiac and systemic tests and were found to have prolapsed mitral valves. Patients with unexplained ocular emboli should be examined by a cardiologist for possible mitral valve prolapse.

Adolescent↗
PubMed1980

Helium ion charged particle therapy for choroidal melanoma.

Nine patients with choroidal melanomas were treated with helium ion charged particle irradiation. No patient demonstrated tumor enlargement, and most lesions followed for more than five months have demonstrated tumor shrinkage. The most effective method of choroidal melanoma management is unclear. Heavy charged particle irradiation may be more applicable and have less ocular morbidity associated with it in either radioactive plaques or photocoagulation.

Adult↗
PubMed1980

Diffuse melanoma of the choroid.

An 81-year-old woman with good vision was followed up with the diagnosis of a minimally active melanoma. This tumour was eventually found to be a diffuse melanoma with extraocular extension. Diffuse melanomas of the uvea are difficult to diagnose, have frequent and early extrascleral extension, and have a poorer prognosis than most melanomas of the uveal tract.

Aged↗
PubMed1980

Extracapsular cataract extraction and pseudophakos implantation in primates: a clinico-pathologic study.

Eighteen Rhesus monkeys underwent lens implantation with Choyce Mark VIII, Binkhorst iridocapsular, and Shearing posterior chamber lenses. They were sacrificed 4 to 28 months following surgery. The eyes were compared clinically and histologically. Controls included unoperated eyes and eyes with lens extraction without implantation. Several histologic findings pertained equally to cataract extraction with or without lens implantation. Late opacification of the posterior capsule was caused by migration and fibrous metaplasia of the lens epithelial cells. These cells appeared to undergo such metaplasia only when exposed directly to aqueous, never when they were in firm apposition to another tissue such as another layer of capsular epithelium, lens cortex, or iris. Also strong fibrous posterior synechiae between the iris and lens remnants occurred only where the anterior lens capsule was missing. All implants were well tolerated clinically. Histologically they showed remarkably little inflammation. The eyes with Binkhorst lenses had a mild tendency to focal loss of iris pigment epithelium and some showed pigmented macrophages in the iris stroma and trabecular mesh. The Choyce lenses frequently displayed marked displacement and thinning of the iris root, and occasionally showed a few chronic inflammatory cells and thin fibrous encapsulation around the implant feet. The Shearing lenses had no effect on the adjacent ciliary body when the loops were well seated in the lens capsule, but when a loop was anterior to the capsule, it eroded into the ciliary body. The loops developed a thin fibrous capsule within the ciliary body with very little chronic inflammatory reaction, but the long term effect of such loops lying in the ciliary body is undetermined. At present it is recommended that, if such a lens is implanted, every effort be made to ensure both loops lie in the capsular envelope. On the basis of this study, it is also recommended that in removing such a lens, one must assume that a loop might lie embedded in the ciliary body and cut the lens free from the loops before removing it.

Animals↗
PubMed1979

Pupillary membrane excision and anterior vitrectomy in eyes after uveitis.

Three patients with uveitis and dense pupillary membranes, total synechial closure of the angle, and low or normal pressure, underwent membranectomy and anterior vitrectomy via a limbal approach using scissors and a vitrectomy instrument. Postoperatively all regained useful vision that has been maintained for over two years despite the persistence of angle closure in all cases and severe hypotony in two.

Adult↗
PubMed1978

Endothelial damage with phacoemulsification and intraocular lens implantation.

Specular microscopy was used to study the corneal endothelium in a series of patients undergoing phacoemulsification with and without intraocular lens implantation by one experienced surgeon. Cell loss after phacoemulsification alone was variable, but the mean was 18%, with a median of 11%. The patients undergoing phacoemulsification plus lens implantation showed a mean cell loss of 26%, with a median of 17%. This is considerably lower than has been reported with standard intracapsular extraction plus lens implantation. The decreased endothelial damage is attributed to the technique of inserting the lens through a small incision and maintaining an air bubble between the lens and the cornea throughout lens insertion and wound closure.

Aged↗
PubMed1977

An ultrasonographic study of the persistence of buckle height three years after segmental sponge explants.

We studied a consecutive series of rhegmatogenous retinal detachments treated with segmental silicone sponge explants and cryotherapy, with or without drainage, approximately three years postoperatively by ultrasonography to determine the degree and persistence of the height of the buckle measuring 1.5 to 3 mm remained in all patienst examined clinically and ultrasonographically at three years or later. Five of these patients reexamined one year later demonstrated no loss of buckle height between the third and fourth postoperative years. By comparison, in a small group of patients examined early in their postoperative course (2.5 to 4 months), the buckles were only slightly higher than in the group studied at three years. Buckle height thus appeared to stabilize relatively quickly postoperatively and to persist at least three years. We believe encapsulation of the sponge by scar tissue must contribute to the long-term maintenance of buckle height.

Cryosurgery↗
PubMed1977

Retinal neoplasia and dysplasia. II. Retinoblastoma occurring with persistence and hyperplasia of the primary vitreous.

The occurrence of retinoblastoma in an eye with persistent hyperplastic primary vitreous (PHPV) is reported. These are both rare lesions. The absence of previous reports of their association has led to the clinical impression that the occurrence of PHPV in a microphthalmic eye precludes the presence of retinoblastoma. The coexistence of these lesions in the present case may represent a coincidence. Their occurrence in the same eye is felt to be noteworthy, nontheless, because of its clinical implications and the possibility of a common underlying etiology.

Eye Neoplasms↗
PubMed1976

Recurrent amyloid involvement in the virreous body after vitrectomy.

A patient with vitreous opacification due to primary familial amyloidosis underwent bilateral vitrectomy via the pars plana with excellent visual results. Two and one half years later opacification of the vitreous body recurred in the retrolental area bilaterally, necessitating a repeat vitrectomy in the left eye. This opacity was successfully removed from the posterior surface of the lens without apparent damage to the lens.

Aged↗