Biomedical subjects
Publications and source records attributed to G W Cleasby.
A 13-year-old white male was found to have a melanoma of the iris. Three treatments with xenon arc photocoagulation resulted in regression of the lesion with development of an iris coloboma. There were no complications, and corrected visual acuity has remained at 20/15 after a 19-year follow-up.
Explore the source record for details and available documents.
A 66-year-old man had malignant melanoma of the choroid that enlarged during a two-year period while a retinal detachment developed. Treatment consisted of a cobalt 60 plaque placed to deliver a dose of 35,000 rads to the base and 9,000 rads to the apex of the tumor. Clinical response was excellent and complete regression occurred. The patient later died of an unrelated disease. Histopathologic study verified complete regression of the tumor.
Corneal alterations from hard contact lens wear can have significant effects on the results of intraocular lens (IOL) calculation and this should be kept in mind in those patients who are candidates for lens implantation. Seven patients were studied during and two weeks after hard contact lens wear, showing an average increase of +0.79 +/- 1.05 (P less than 0.05) in keratometry reading and an average decrease of -0.98 in emmetropic IOL calculations after discontinuing contact lens wear. Since the effect of hard contact lens wear on corneal curvature and resultant IOL calculations is variable and unpredictable, it is important that IOL calculations be made well after discontinuation of hard contact lens wear.
Eight family members had familial exudative vitreoretinopathy. They exhibited a variety of clinical stages of the disease process. Some clinical findings included retinal detachment, fibrovascular masses with dragged disc and macula, neovascular fronds and intraretinal deposits. The fundus and angiographic findings were found to be similar to those in cases reported previously. Electroretinograms were normal. Of particular interest in this pedigree was the sole clinical finding of isolated intraretinal deposits in four family members. This characteristic may represent a mild expression of the disease and warrant appropriate genetic counseling. Our study confirms the variable clinical expression of the disease.
Pars plana endoscopy was used to guide removal of a large nonmagnetic intraocular foreign body from an eye with corneal scarring and irregularity of such a degree the view through the operating microscope was not adequate to permit such surgery.
We have successfully used a new small endoscope in posterior segment surgery in situations where the operating microscope or binocular indirect ophthalmoscope provided an inadequate view. In this series of 18 procedures, we preformed posterior vitrectomies, removed retained foreign bodies, and reattached persistent retinal detachments. The only major complication was a retinal detachment. Learning to use a monocular system requires practice and preparation with experimental animals.
Orbital endoscopy is useful in managing various types of orbital problems. A hand-held endoscope can be used for simple procedures. Surgery and prolonged observation require a mounted endoscope. These two techniques provided good results in 15 patients. Endoscopy proved useful in finding and removing orbital foreign bodies. It is potentially useful in the management of orbital tumors, but experience in this area is still limited.
Selected vitreous surgery techniques can provide effective and safe means of supplementing anterior segment surgery for correction or avoidance of many problems. In my experience, the guillotine or piston action vitrectomy instruments are more effective and safer than those which have a rotating or oscillating action. Pars plana vitreous surgery has added a new dimension to anterior segment surgery. There is reason to hope that the future will bring further refinements of instrumentation and surgical technique and more precise knowledge of the indications and limitations of this type of surgery.
In a series of 357 cases, vitreous surgery instruments were employed via a pars plana approach for supplementation of cataract surgery. The most frequent use was for supplementation of primary cataract surgery, either to correct vitreous loss or for performance of posterior capsulectomy. Other frequent indications included secondary cataract ("after-cataract"), retro-implant membrane, and PHPV. Improved vision was obtained in 84.3%, excluding cases in which the vitreous surgery was combined with primary cataract extraction. The complication rate was low, the most frequent problem being the presence of symptomatic cystoid macular edema in 9.2% of cases.
The technique of bimanual phacoemulsification utilizing a microsurgical spatula has been found very useful to me and to others who have learned this method.
Explore the source record for details and available documents.
Information on the fate of the fellow eye in patients who have suffered loss of central vision in the first eye due to exudative senile maculopathy suggests that there is a high incidence of later loss of vision in the second eye due to the same disease process. It has been speculated that prophylactic photocoagulation of the macula in the fellow eye might have a protective effect. This is a preliminary report of a series of patients in which argon laser photocoagulation of the second eye has been performed.
An endoscope with a 1.7-mm diameter shaft has unique properties of focus, magnification, and large field of view that make it useful for both orbital and intraocular surgery.
Explore the source record for details and available documents.
Two independent, double-masked, controlled studies were made to evaluate the efficacy of calcium dobesilate for the treatment of nonproliferative diabetic retinopathy. Forty-two patients underwent a six-month crossover evaluation while receiving calcium dobesilate (750 mg per day) and placebo in random order. Thirty-six patients received calcium dobesilate (1,000 mg per day) or placebo for one year. Evaluation by clinical examination, fluorescein angiography, angiography, and fundus photography failed to demonstrate any beneficial effect of calcium dobesilate.
Hypotony after intracapsular cataract extraction was prolonged in 3 eyes because cyclodialysis clefts were inadvertently formed. One eye became normotensive with the topical application of corticosteroid; 2 required surgical intervention.
Explore the source record for details and available documents.