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PubMed1983

The arterially perfused enucleated rabbit eye as a model for studying aqueous humor formation.

The rate of turnover of aqueous humor (Kout), as measured by the decay of radioactive inulin from the anterior chamber of the enucleated eye, was similar to the rate of loss of 125I-RISA (radioiodinated serum albumin) from the eye of a living rabbit. Arterial perfusion with 125I-RISA or rabbit serum showed that the permeability characteristics of the blood-aqueous barrier to protein molecules are unaffected in the enucleated eye. The viability of the enucleated eye for secretion of ascorbic acid was also examined, but the results were inconclusive.

Animals↗
PubMed1975

The effect of intraocular pressure on conventional outflow resistance in the enucleated human eye.

A technique for measuring resistance to outflow in enucleated eyes is described. The technique minimizes the artifactual effects of ocular stretching and anterior chamber deepening. Using this perfusion technique, it was found that the resistance to outflow in normal, enucleated human eyes increases directly and linearly with intraocular pressure. This phenomenon, termed the outflow obstruction effect, was defined as the fractional increase in baseline outflow resistance (outflow resistance at an outflow pressure of zero) per millimeter of Hg intraocular pressure rise above baseline and was designated by the letter Q. The value of Q was found to be 0.012 mm. Hg-1 plus or minus 0.0014 indicating that the outflow resistance rise above its baseline value approximately 1 per cent per millimeter of Hg rise in intraocular pressure. Estimates of Q, calculated from data published by other investigators over the past two decades, are also included.

Anterior Chamber↗
PubMed1982

N-ethylmaleimide increases the facility of aqueous outflow of excised monkey and calf eyes.

Freshly enucleated eyes were quantitatively perfused via the anterior chamber at 15 mm Hg pressure with various concentrations of the sulfhydryl (-SH) agent. N-ethylmaleimide (NEM). In the monkey eye a dosage of 9.4 mM NEM produced a 108% increase in facility of outflow. In calf eyes a dosage of NEM of 4.7 mM or greater also produced a significant increase in outflow facility. At the threshold dosage of 4.7 mM NEM there was only slight (12%) inhibition of glycolysis in the calf meshwork, which was excised after perfusion. The results suggest that the effect of NEM on outflow facility is not caused by a metabolic inhibitory action. We propose that alteration of cell membrane -SH groups in the outflow pathways can influence aqueous outflow resistance.

Animals↗
PubMed1980

Plasticity and interaction after ablations of visual or somatosensory motor cortex or retina in neonatal rats.

The results obtained following eye enucleation and dorsal occipital cortical (DOC) lesion in normal adult animals are in general agreement with those reported in previous work. The details, however, vary somewhat. A DOC projection to the claustrum and reticularis thalami is reported here for the first time in the rat. Six experiments were performed: (1) DOC lesions followed by eye enucleations. (2) Eye enucleations followed by DOC lesions. (3) Eye enucleations followed by sensorimotor cortical (SMC) lesions. (4) SMC lesions followed by eye enucleations. (5) DOC lesions followed by SMC lesions. (6) SMC lesions followed by DOC lesions. The results obtained from the experimental animals demonstrate a certain degree of plasticity and interaction between the DOC and retinal efferents to the superior colliculus, lateral geniculate nucleus, the pretectal region and the superior colliculus. Thus, following a neonatal left dorsal occipital cortical lesion, the retinal efferents from the right eye produce a denser projection to the contralateral lateralis posterior (LP), nucleus lateralis of the optic tract (NLOT), and the caudal part of the lateral division of the lateral geniculate nucleus pars ventralis (VGN). Following neonatal left eye enucleation, increased ipsilateral projection from the right DOC was noted in the superficial part of the stratum griseum superficiale (SGS), NLOT, pretectal nucleus (PT) and the adjoining stratum griseum intermediate (SGI) of the superior colliculus, lateral geniculate nucleus, pars dorsalis (DGN), and both the medial and lateral halves of the caudal portion of VGN. Following a neonatal DOC lesion a denser projection from the remaining ipsilateral SMC was seen in the medial pretectal nucleus (PTM), PT and deep pretectal nucleus (PTP). Following a neonatal SMC lesion a denser projection from the ipsilateral DOC was seen in the SGI, PT, nucleus medialis of the optic tract (NMOT) and PTM. There was no change in the retinal efferents following neonatal SMC lesions. Nor was there any change in the SMC efferents following neonatal eye enucleations.

Animals↗
PubMed1994

Erbium:YAG laser photothermal retinal ablation in enucleated rabbit eyes.

The erbium:YAG laser has been shown to produce precise tissue ablation because of the high water absorption of the 2.94-microns wave-length emitted by this laser. We used an experimental system to create lesions of various depths in the surface of the rabbit retina in enucleated eyes in vitro to examine the potential application to maneuvers such as retinotomy and the removal of epiretinal membranes in vitrectomy. With an air/retinal interface, single pulses produced discrete craters in the retinal surface with a depth proportional to fluence, ranging from 30 microns for a pulse of 1.3 J/cm2 to a full-thickness retinotomy at 3.9 J/cm2. An adjacent zone of coagulated tissue ranging in size from 15 to 40 microns was noted. Multiple pulses had an additive effect. With a fluid/retinal interface, 20 pulses of 3.6 J/cm2 produced a full-thickness retinotomy, with an adjacent zone of damaged tissue up to 1 mm, caused by effects of volatilization of intervening fluid. The erbium:YAG laser may have a role in vitreoretinal surgery.

Animals↗
PubMedDate not supplied

Evaluation of increased aqueous outflow after radial keratotomy in enucleated bovine eyes.

PURPOSE: We studied the efficacy of using radial keratotomy incisions as a surgical method of increasing outflow facility in enucleated bovine eyes. METHODS: Each freshly enucleated bovine eye (n = 23) was cannulated to a system measuring the rate of flow into the eyes. Preoperatively, corneal thickness measurements were determined for all treated eyes. Radial keratotomy was performed in 13 eyes and a control set of eyes (n = 10) had no surgical manipulation. The intraocular pressure was set at 16.9 mm Hg. A clear zone of 10 mm was used for each eye with the incision depth set at 100% of the pachymetric reading. One set of experimental eyes had incisions that remained in the clear cornea, and the other set had incisions that reached 2 mm beyond the limbus into sclera. Preoperative outflow measurements were performed on each eye. Postoperative measurements were made after 10 incisions and 20 incisions. All eyes were checked for perforation after surgery and discarded if a perforation was found. RESULTS: No eye included in the analysis was perforated. The preoperative (baseline) total flow rate was 27.90 +/- 3.72 mu 1/min at 16.9 mmHg. The flow rate increased by 23.5% (over baseline) with 20 radial keratotomy incisions. A paired t-test was used to statistically compare the outflow measurements before radial keratotomy and after the first and second set of radial incisions. The increases in flow were found to be statistically significant (P < .005) for both 10 and 20 radial incisions. CONCLUSION: Assuming the flow measurements (flow rate) in these experiments parallel outflow facility, radial keratotomy increases the outflow facility in enucleated bovine eyes.

Animals↗
PubMed2006

Optical coherence tomography of peripheral retinal lesions in enucleated human eye specimens with histologic correlation.

PURPOSE: To report optical coherence tomography (OCT) histologic correlations of three common peripheral retinal lesions and to explore the feasibility of the use of OCT to image retinal pathologic conditions in fixed tissue specimens. DESIGN: Experimental study. METHODS: We studied peripheral retinal lesions that were available to us in 11 formalin-fixed caps of seven human eyes that had been enucleated previously for choroidal melanoma. OCT scans were performed through these lesions, and the images were correlated with corresponding histologic sections. RESULTS: Three peripheral retinal diseases that included cystoid degeneration, localized retinal detachment, and paving stone degeneration were imaged successfully, and their optical characteristics correlated well with their histologic data. CONCLUSION: We explored potential utility for OCT imaging of peripheral retinal pathologic conditions in fixed tissue specimens. That these OCT images correlate with findings from histologic sections suggests a possible role for OCT in the eye pathology laboratory.

Choroid Neoplasms↗
PubMed1998

Intraocular neoplastic cyst from mucoepidermoid carcinoma of the conjunctiva.

An 89-year-old woman with recurrent conjunctival mucoepidermoid carcinoma developed intraocular inflammation and an elevated fundus lesion that simulated choroidal detachment in her affected right eye. Intraocular invasion of squamous cell carcinoma was suspected and the eye was enucleated. Pathologic examination of the enucleated eye showed intraocular invasion by conjunctival mucoepidermoid carcinoma that formed a suprauveal cyst lined with malignant epithelial cells. The patient developed an orbital recurrence 1 year later and underwent orbital exenteration. She died 2 years later from an unrelated cause. Conjunctival mucoepidermoid carcinoma can exhibit intraocular invasion and produce an intraocular neoplastic cyst.

Aged↗
PubMed1996

Immunocytochemical features of retinoblastoma in an adult.

OBJECTIVE: To describe the clinical course and immunocytochemical characteristics of an unusual intraocular tumor. METHODS: Immunocytochemical analysis of the enucleated eye with an intraocular mass that markedly waxed and waned in size during 1 year of close observation of a 29-year-old woman. RESULTS: Most of the tumor was composed of either dying or rapidly proliferating cells. One area located near the retina consisted mostly of well-differentiated cells in uniform sheets (bacillettes) with lacelike glial processes between the tumor cells. Almost all of the differentiated tumor cells were positive for S antigen. In particular, the dominant cell type stained positively for both antibodies known to be specific for those isoforms of S antigen found only in blue cones and rods but not in red or green cones. Only a few of these cells labeled positively with an anti-rhodopsin antibody. CONCLUSIONS: This is the first case of adult retinoblastoma to be confirmed immunocytochemically. The tumor was unusual because the differentiated regions contained bacillettes composed mostly of blue cones. It is possible that this and other adult retinoblastomas may arise from previously existing retinocytomas.

Adult↗
PubMed1992

Cryptococcosis of the anterior segment in acquired immune deficiency syndrome.

Cryptococcosis is a rare form of human ocular infection, usually occurring in immunocompromised patients. Unilateral or bilateral posterior segment involvement is the rule. The authors describe a unique case of intraocular cryptococcosis presenting as an iris inflammatory mass in a patient with acquired immune deficiency syndrome. Diagnosis was established by anterior chamber paracentesis and confirmed by histopathologic examination of the enucleated eye.

Acquired Immunodeficiency Syndrome↗
PubMed1995

Long-term follow-up of the Allen implant. 1967 to 1991.

PURPOSE: The objectives of this study are to determine the incidence of superficial tissue breakdown and/or exposure of the Allen implant, to identify potential risk factors for superficial tissue breakdown and/or exposure of the Allen implant, and to provide a comparison for future studies of other orbital implants. METHODS: The authors retrospectively studied 186 consecutive patients managed with enucleation and Allen implant placement from January 1967 through December 1991. Information was obtained from a review of the patients' records and from telephone and letter surveys. RESULTS: More than half of the patients had follow-up more than 5 years and approximately one third had follow-up of 10 or more years. The mean length of follow-up was 7.8 years. Two allen implants (1.1%) became exposed 5.3 and 11.5 years, respectively, after initial implant placement and were subsequently replaced by dermis fat grafts. Superficial tissue breakdown without implant exposure occurred over four additional Allen implants (2.2%); the patients satisfactorily were treated medically or surgically without the need for removal or replacement of the Allen implant. Most prostheses have horizontal and vertical excursions of 30 degrees or more. CONCLUSION: The satisfactory motility, the low incidence of superficial tissue breakdown, and the even lower incidence of exposed Allen implants observed in our long-term follow-up study provide evidence that the Allen implant is a satisfactory choice to replace the enucleated eye. The absence of implant exposure occurring before 5 years of follow-up underscores the need for long-term follow-up to properly evaluate newer orbital implants.

Adolescent↗
PubMed1997

Workup for metastatic retinoblastoma. A review of 261 patients.

PURPOSE: The means available to screen for retinoblastoma metastases, including bone marrow aspiration, lumbar puncture, and radionuclide scans, offer variable usefulness at different stages of the disease. In this study, the authors attempted to assess the value of these tests as part of the initial workup for metastases. METHODS: Medical files of 261 patients with retinoblastoma were reviewed, and the results of bone marrow, lumbar puncture, and bone and liver radionuclide scans were correlated with the laterality, clinical staging, and histopathologic findings. The presence or absence of tumor in the choroid and the optic nerve also were correlated with the results of diagnostic tests. RESULTS: Of 261 patients with retinoblastoma, 147 (56.3%) and 114 (43.7%) had unilateral and bilateral disease, respectively; 11.6% of unilateral cases and 14.9% of bilateral cases had distant metastasis (P = 0.2). Bone marrow aspirations were performed on 101 patients (38.7%), and 10 (9.9%), of these specimens showed the presence of retinoblastoma cells in the aspirate. Ninety-four (36%) of the patients were examined with spinal tap cytology, and the results of four (4.3%) of these were positive for tumor cells. Radionuclide bone and liver scans were performed on 49 (18.8%) and 48 (18.4%) patients, respectively; 5 (10.2%) had abnormal bone scans and 3 (6.2%) had abnormal liver scans. The average age in the metastatic group was 3.1 years, whereas the average age in the nonmetastatic group was 2.3 years. All of our abnormal test results were found in patients with stages III and IV disease, with the exception of one abnormal lumbar puncture in a patient with stage II disease. The correlation of diagnostic tests with the histopathologic findings showed that with no choroidal involvement, no positive diagnostic tests were encountered. Correlation between positive diagnostic test results and the level of optic nerve involvement failed to indicate any trends. CONCLUSION: Our study indicated a good interrelation between the positivity of diagnostic tests (bone marrow and bone scan) and higher stages of the disease (stages III and IV) and choroidal involvement in enucleated eyes, with statistically significant correlations; correlations with lumbar puncture and liver scan were not significant.

Adolescent↗
PubMed1999

Coats' disease of the retina (unilateral retinal telangiectasis) caused by somatic mutation in the NDP gene: a role for norrin in retinal angiogenesis.

Coats' disease is characterized by abnormal retinal vascular development (so-called 'retinal telangiectasis') which results in massive intraretinal and subretinal lipid accumulation (exudative retinal detachment). The classical form of Coats' disease is almost invariably isolated, unilateral and seen in males. A female with a unilateral variant of Coats' disease gave birth to a son affected by Norrie disease. Both carried a missense mutation within the NDP gene on chromosome Xp11.2. Subsequently analysis of the retinas of nine enucleated eyes from males with Coats' disease demonstrated in one a somatic mutation in the NDP gene which was not present within non-retinal tissue. We suggest that Coats' telangiectasis is secondary to somatic mutation in the NDP gene which results in a deficiency of norrin (the protein product of the NDP gene) within the developing retina. This supports recent observations that the protein is critical for normal retinal vasculogenesis.

Amino Acid Substitution↗
PubMedDate not supplied

Sympathetic ophthalmia in vater association combined with persisting hyperplastic primary vitreous after cyclodestructive procedure.

PURPOSE: To report on the occurrence of histology-proven sympathetic ophthalmia in a patient with VATER association and persisting hyperplastic primary vitreous (PHPV) after a cyclodestructive procedure was performed to treat secondary angle-closure glaucoma. METHODS: The left eye of a 13-year-old boy with VATER association was microphthalmic from birth and had been diagnosed with PHPV at age 1 year. It developed iris neovascularization and secondary angle-closure glaucoma, which was treated by combined cyclocryocoagulation and cyclophotocoagulation. Six weeks later, a bilateral fibrinous iritis developed. Despite intensive topical and systemic steroid treatment, the iritis persisted so that the left blind eye was enucleated. RESULTS: Histology of the enucleated eye showed a marked intraocular inflammation with lymphocytes, epithelioid cells, and multinuclear giant cells grouped around remnants of melanin-bearing cells. CONCLUSIONS: Sympathetic ophthalmia may occur in patients with VATER association and PHPV after a secondary angle-closure glaucoma is treated by a combined cyclocryocoagulation and cyclophotocoagulation.

Abnormalities, Multiple↗
PubMedDate not supplied

Causes of enucleation of the eye at Lagos University Teaching Hospital. A study of 101 eyes.

Causes of enucleation of the eye at Lagos University Teaching Hospital over a period of 10 years - January, 1976 - December, 1985 were reviewed. One hundred and one (5.7%) eyes were enucleated out of the 1758 eye operations performed over this period. Most of the patients were below the age of 30 but their mean age was 14.5 years. The three commonest causes of enucleation were tumours (41.7%) chronic inflammatory diseases (16.8%) and glaucoma (12.3%). Retinoblastoma was the commonest tumour encountered, and most of the patients presented late leaving enucleation as the main line of treatment. Staphyloma is the commonest chronic inflammatory disease, and frequently due to measles. Injury accounted for only (7.9%). Positive measures to eradicate measles and to reduce trauma are advocated.

Adolescent↗
PubMed2000

Cataract in enucleated goat eyes: training model for phacoemulsification.

We developed an inexpensive, reproducible technique of inducing cataract in enucleated animal eyes for phacoemulsification training. Injection of 0.3 to 0.5 mL of formalin 20% in the central and paracentral portion of the crystalline lens in a goat's eye induced cataract in about 5 to 10 minutes. Varying the interval would enable novice surgeons to practice different techniques of phacoemulsification based on cataract hardness.

Animals↗