The potential usefulness to research of retina obtained by biopsy.

Retinal biopsy has been performed on normal rabbits and dogs. It was shown that retinal samples could be obtained by internal and external routes in rabbits, but in dogs inability to achieve adequate vitrectomy precluded useful retinal biopsy by the internal route. A single external biopsy specimen of 3 mm diameter was more than adequate to undertake standard histopathological examination, immunocytochemical experiments and determination of cyclic nucleotide levels. The quality of the micrographs, immunocytochemical labelling of rhodopsin and phosphodiesterase, and cyclic nucleotide analyses were similar to those obtained with retinas from freshly enucleated eyes. The surgical exercise was well tolerated by most eyes and does not preclude serial biopsies being undertaken. It is concluded that retinal biopsy provides material of sufficient quantity and quality to satisfy many laboratory needs in retinal research.

Experimental immunogenic rubeosis iridis.

We have developed a primate model of rubeosis iridis in monkeys systemically sensitized to crystalline beef insulin. After intravitreal insulin injection, the dose-related immunogenic inflammation includes cells, flare, fibrin, and blood in the anterior chamber. With more severe inflammation, posterior synechiae, iris bombé, and cataracts occur. Of particular importance, new blood vessels develop within the stroma and on the anterior surface of the iris. Following injection of small amounts of insulin, the anterior surface vessels may regress over time, and the iris regains its normal appearance and coloration. However, the new stromal vessels persist and are cuffed by inflammatory cells including plasma cells. After injection of large amounts of insulin, more extensive structural alterations develop as noted above in conjunction with persistent iris anterior surface and stromal neovascularization. The relationship of rubeosis iridis to clinical inflammatory syndromes and to previous laboratory studies is discussed. Stromal neovascularization was a consistent finding in this experimental model even when anterior surface vessels regressed. On the basis of these experimental data and a review of publications describing human pathology, we believe that a broadening of the classic definition of rubeosis iridis is waranted to include a recognition of the stromal component of the clinical and pathologic findings.

Detection of cytoplasmic S-100 protein in primary and metastatic intraocular melanomas.

The authors sought S-100 protein in sections cut from formalin- or glutaraldehyde-fixed, paraffin-embedded tumors from the eye and other sites by an immunoperoxidase technique, using rabbit antibovine S-100 protein antiserum, swine antirabbit serum, a peroxidase-antiperoxidase preparation, and amino-ethylcarbizole as developer. Tissue from 26 intraocular tumors was examined, the pathologic diagnosis being unknown to the investigators at that time that the tests were performed. Thirteen of 16 malignant melanomas of the choroid contained S-100 protein (81%), while only one of seven retinoblastomas contained S-100 protein (14%). One cutaneous malignant melanoma metastatic to the eye contained S-100 protein, while none of three metastatic nonmelanocytic, nonneural tumors contained the protein. These results are similar to our findings with nonocular tumors, in which 56 of 56 cutaneous melanomas contained S-100 protein (100%) and only 1 of 51 nonneural, nonmelanocytic tumors contained S-100 protein (2%). S-100 protein may be useful as a marker for ocular malignant melanoma.

2.5% v 10% phenylephrine in maintaining mydriasis during cataract surgery.

A 10% viscous solution of phenylephrine hydrochloride was more effective than a 2.5% aqueous solution of phenylephrine hydrochloride in maintaining mydriasis during extracapsular cataract surgery. The pupil area after nucleus expression was 57% larger with the stronger phenylephrine concentration. The difference in pupil area was greater in darkly pigmented irides (114%) than in moderately pigmented (70%) or lightly pigmented irides (12%). Mean BP elevations following phenylephrine administration were not higher in the group receiving the 10% solution than in the group receiving the 2.5% solution. In darkly pigmented irides, a 10% viscous solution of phenylephrine hydrochloride is more effective than a 2.5% concentration in maintaining mydriasis during cataract surgery.

Small malignant melanoma of the choroid with extraocular extension.

A disciform macular lesion in the hyperpigmented eye of a patient with melanosis oculi demonstrated slowly progressive increase in size during eight years. Clinical observation and serial fundus photography indicated increase in anteroposterior thickness of the lesion to 2.0 mm and in greatest diameter from 3.5 to 6.0 mm. Subsequent echography revealed an overall anteroposterior dimension of 3.4 mm and an increase to 5.5 mm in 20 months. Enucleation of the affected eye with the intact extraocular tumor mass and a local tenonectomy demonstrated a choroidal malignant melanoma of the epithelioid cell type with extraocular extension, peripapillary scleral infiltration, focal invasion of the juxtalaminar optic nerve, and tumor cells in the subarachnoid space. This experience emphasizes the importance of echography in the periodic evaluation of small choroidal malignant melanomas to detect growth not apparent by ophthalmoscopy.

The COMS randomized trial of iodine 125 brachytherapy for choroidal melanoma, II: characteristics of patients enrolled and not enrolled. COMS Report No. 17.

OBJECTIVES: To describe characteristics of patients evaluated for the Collaborative Ocular Melanoma Study (COMS) randomized clinical trial of iodine 125 brachytherapy for choroidal melanoma by enrollment status, and to compare characteristics of patients enrolled with those of patients with tumors of eligible size who did not enroll in order to assess the extent to which findings from the clinical trial can be generalized to future patients. METHODS: For all patients diagnosed with choroidal melanoma and evaluated for the clinical trial at COMS centers from November 1986 through July 31, 1998, selected data were transmitted to the COMS Coordinating Center, Baltimore, Md, where they were integrated and analyzed. Data included ophthalmic and medical history, examination findings, and visual acuity measurements recorded prior to enrollment; standardized A- and B-scan echographic examination findings; and wide-angle fundus photographs and fluorescein angiograms. RESULTS: Of 8712 patients with choroidal melanoma, 5046 had tumors of eligible size; of these, 2882 (57%) were eligible for enrollment, and 1317 (46% of eligible patients, 26% of patients with tumors of eligible size) enrolled. Most differences between eligible and ineligible patients corresponded to eligibility and exclusion criteria. However, ineligible patients were older and had thicker tumors than eligible patients. Eligible patients who enrolled were slightly older and had larger tumors than those who did not enroll. Nearly half (48%) of enrolled patients had choroidal melanoma with the apex located temporal to the fovea, compared with 40% of eligible patients not enrolled and 29% of ineligible patients. CONCLUSIONS: This trial was designed to yield internally valid treatment comparisons through random assignment to treatment at time of enrollment. Information from this and other studies document that enrolled patients were similar to other patients with choroidal melanoma who were treated with 125I brachytherapy. These findings support the external validity of the trial and applicability of treatment findings to all patients who meet the criteria used to judge eligibility for the trial.

The COMS randomized trial of iodine 125 brachytherapy for choroidal melanoma, III: initial mortality findings. COMS Report No. 18.

OBJECTIVES: To report initial mortality findings from the Collaborative Ocular Melanoma Study (COMS) randomized clinical trial of iodine 125 brachytherapy vs enucleation for treatment of choroidal melanoma. METHODS: Patients were evaluated for eligibility at 43 participating clinical centers in the United States and Canada. Eligible consenting patients were assigned randomly at the time of enrollment to enucleation or 125I brachytherapy. Patients were examined at specified intervals after enrollment for data collection purposes. Findings presented herein are based on data received by September 30, 2000. Data for each patient were analyzed with the treatment group to which the patient was assigned randomly at the time of enrollment. RESULTS: During the 11(1/2)-year accrual period, 1317 patients enrolled; 660 were assigned randomly to enucleation and 657 to 125I brachytherapy. Only 2 patients in the enucleation arm were found to have been misdiagnosed when histopathology was reviewed centrally. All but 17 patients (1.3%) received the assigned treatment. Adherence to the brachytherapy protocol was excellent, with 91% of patients treated per protocol. Based on time since enrollment, 1072 patients (81%) had been followed for mortality for 5 years and 416 (32%) for 10 years. A total of 364 patients had died: 188 (28%) of 660 patients in the enucleation arm and 176 (27%) of 657 patients in the brachytherapy arm. The unadjusted estimated 5-year survival rates were 81% and 82%, respectively; there was no clinically or statistically significant difference in survival rates overall (P =.48, log-rank test). The adjusted estimated risk ratio for 125I brachytherapy vs enucleation was 0.99 (95% confidence interval [CI], 0.80-1.22). Five-year rates of death with histopathologically confirmed melanoma metastasis were 11% and 9% following enucleation and brachytherapy, respectively; after adjustment, the estimated risk ratio was 0.91 (95% CI, 0.66-1.24). CONCLUSIONS: Mortality rates following 125I brachytherapy did not differ from mortality rates following enucleation for up to 12 years after treatment of patients with choroidal melanoma who enrolled in this COMS trial. The power of the study was sufficient to indicate that neither treatment is likely to increase or decrease mortality rates by as much as 25% relative to the other.

Apparent disappearance of a macular hole associated with development of an epiretinal membrane.

A macular hole in a 78-year-old man participating in a long-term follow-up study changed its biomicroscopic appearance dramatically as a result of changes in an epiretinal membrane. The macular hole became invisible and visual acuity improved from 20/70-2 to 20/30-2+2.

Methyl bromide optic atrophy.

A 32-year-old fumigation assistant developed systemic and neuro-ophthalmic manifestations of methyl bromide poisoning, including increased serum bromide level (6.6 mg/100 ml), paresthesias and burning dysesthesia on his hands and feet, and visual impairment. Ocular examination showed mild bilateral decrease in vision, temporal optic nerve head pallor, severely attenuated visual-evoked response amplitudes and normal latencies, a normal electroretinogram, an abnormal electrooculogram, and a severe deuteranomalous (green) defect on Farnsworth-Munsell 100-hue testing. His vision had not improved 12 months after the initial exposure.

Fluorescein angiography in reticular degeneration of the pigment epithelium.

We studied reticular degeneration of the pigment epithelium by fluorescein angiography in 32 eyes of 50 consecutive patients who had ophthalmoscopic indications of this aging-related entity. In this type of degeneration, fluorescein angiography delineated extensive abnormalities of the retinal pigment epithelium and demonstrated normal-appearing retinal vessels and choriocapillaries in the affected areas.

Resorption of intravitreal blood following vitrectomy.

Eight rhesus monkeys underwent unilateral vitrectomy and subsequent injection of blood into both vitreous cavities. There was no significant inflammation, cataract, delayed corneal healing, or elevated intraocular pressure. Blood in the operated eyes dispersed immediately while blood in the control eyes did not disperse until seven to 14 days after injection. All operated eyes showed more rapid clearing of blood than control eyes containing formed vitreous. This result occurred in the presence or absence of the crystalline lens.

Posterior vitreous cyst.

We observed two patients who had unilateral posterior vitreous cysts; one patient had been observed for 17 years. Both patients were young females who reported transient, infrequent obscurations of vision that were not disabling. One involved eye was emmetropic, and the other was highly myopic. No other ocular abnormalities were present. In the patient observed for 17 years, the physical characteristics of the posterior vitreous cyst remained unchanged. With this stable clinical course, posterior vitreous cyst that does not visually disable the patient may be managed by periodic observation.

Lens capsule and epithelium in age-related cataract.

On the basis of preoperative assessment of patient characteristics, intraoperative obtainment of a lens-capsule and epithelium specimen, histopathologic investigation of lens capsule and epithelium, and biochemical analysis of glutathione reductase in lens epithelium, age-related cataract was studied in 50 adult patients who underwent consecutive extracapsular cataract-posterior chamber lens implant surgery. Patients (25 men and 25 women; age range, 41 to 91 years; mean age, 75 years) had a wide range of systemic and ocular disease; 17 of 50 (34%) patients had a history of severe vision-impairing cataract in a first-degree relative. Anterior lens-capsule thickness ranged from 10 to 22 microns, with a mean of 17 microns. Statistical analysis of lens-epithelium ultrastructure in 41 of 50 specimens documented mixing of normal and abnormal cells, verified a gradation in the degree of abnormal ultrastructural features, and demonstrated a statistically significant decrease in epithelial cytologic activity with advancing age (P = .038). Biochemical analysis documented a severe glutathione reductase deficiency in nine of 39 (23%) lens-epithelium specimens, possibly reflecting a dietary deficiency of riboflavin.

Tissue plasminogen activator treatment of experimental subretinal hemorrhage.

To determine if tissue plasminogen activator, a clot-specific fibrinolytic agent, could eventually be used to assist in the clearance or removal of subretinal hemorrhage, we studied the effect of subretinal injections of tissue plasminogen activator, autologous blood, balanced salt solution, and the combination of either tissue plasminogen activator or balanced salt solution after subretinal injection of autologous blood on retinal morphologic characteristics and clearance of subretinal hemorrhage in the albino rabbit. No morphologic evidence of tissue plasminogen activator toxicity was found in the rabbit retina at a dose of 25 to 50 micrograms/0.1 ml. Subretinal hemorrhage cleared faster after subretinal injection of tissue plasminogen activator when compared to balanced salt solution (P = .0005) but did not completely prevent overlying retinal degeneration. Both tissue plasminogen activator and balanced salt solution were found to decrease the toxic effects of subretinal blood on the morphologic characteristics of the rabbit retina, and this effect can be explained at least partly by dilution of the subretinal blood.

Transvitreal chorioretinal biopsy in the rabbit.

Transvitreal chorioretinal biopsy was performed in nine Dutch rabbits by introducing a biopsy instrument through a small eye wall incision, passing the instrument across the eye through the vitreous to the biopsy site, and by trephinating and removing from the eye a 1.6-mm diameter specimen of the posterior eye wall. Biopsy was carried out under stereotaxic control by using a micromanipulator especially designed for ophthalmic surgery. Hemostasis was achieved by circumferential mechanical pressure around the biopsy site. The eye wall defect was sealed by a preplaced explant and repaired by fibrovascular ingrowth from the surrounding choroid and episclera. The normal histologic features of the biopsy specimen were preserved, except for separation of the neurosensory retina from the pigmented epithelium. Complications of the procedure included hemorrhage from the incision site, transvitreal strand formation, and lens abrasion. In no instance, however, did these complications result in significant opacification of the optical media. The biopsy technique has potential use as a clinical procedure in the diagnosis of choroidal tumors and other selected disorders of the choroid and retina and as a technique in investigational animal studies.

Clinicobiochemical correlations in aging-related human cataract. The Pan American Association and American Journal of Ophthalmology lecture.

In a series of 50 consecutive adult patients (24 men and 26 women) we studied aging-related cataract by means of comprehensive presurgical examination of the patient, the eyes, and the cataractous lens; cataract sample collection from predetermined sites during surgery; biochemical analyses with high-performance liquid chromatography of each individual lens sample; and computer-assisted biostatistical data analysis. Compared with normal values established on clear human lenses obtained from a donor eye program, the ratios of 23,000 (23K) crystallin to total beta, gamma, and low molecular weight soluble proteins were statistically significantly lower in the anterior axial lens cortex (P less than .001) and in the lens nucleus (P less than .001). Increased grades of cortex opacification and nucleus opacification were generally associated with progressively decreased 23K crystallin ratios. In this series of patients with diverse cataract-associated systemic diseases, family histories, ophthalmic disorders, and drug-use patterns, decreased 23K crystallin ratios were a sensitive marker for aging-related cataract. Similar biochemical abnormalities in patients with multiple cataract-associated factors may have important clinical implications.

Myelinated retinal nerve fibers associated with ipsilateral myopia, amblyopia, and strabismus.

Four patients had extensive unilateral myelinated nerve fibers associated with ipsilateral myopia, amblyopia, and strabismus. Their profound visual impairment, exotropia, and the early age onset of symptoms indicated that the amblyopia may have been organically caused. Prognosis is poor for even partial correction but good results have been obtained with intense therapy that includes full correction of the refractive error in each eye and extraocular muscle surgery if cosmetically necessary. In patients with axial myopia, images of a similar size will be produced by placing a lens of the correct power at the spectacle plane. In younger patients, a contact lens should not be used to correct the refractive error because it creates an undesirable anisometropia. Younger patients who have parafoveal fixation and no strabismus respond best to amblyopia therapy.

Myelinated retinal nerve fibers.

In a series of 3,968 consecutive autopsies, myelinated nerve fibers of the retina were presented in 39 (0.98%) cases and bilateral in three (7.7%) affected cases; thus, 42 (0.54%) of the 7,936 eyes examined were affected. Myelinated nerve fiber lesions appeared as white or gray-white striated patches corresponding in shape to the distribution of retinal nerve fibers and demonstrated frayed borders. Myelinated retinal nerve fibers were continuous with the optic nerve head in 14 (33%) and discontinuous with the optic nerve head in 28 (66%) affected eyes. By light microscopy and electron microscopy, myelinated retinal fibers were marked by a ganglion cell axon surrounded by concentric lipoprotein lamellae that formed the myelin sheath. Glial cells were often prominent near the myelin sheaths, but other components of the sensory retina were morphologically normal. Clinically, 32 patients with myelinated retinal nerve fibers had comparable overall features, visual field defects less extensive than expected on the basis of ophthalmoscopic appearance, and normal findings on fluorescein angiography. Four patients had a syndrome characterized by ipsilateral extensive myelinated retinal nerve fibers, anisometropic myopia, amblyopia, and strabismus.

Incidence, risk factors, and morphology in operating microscope light retinopathy.

A review of 135 consecutive cataract operations identified ten cases (7.4%) of operating microscope light retinopathy. Ophthalmoscopically, these light retinopathy lesions appeared as a focal pigment epithelial change with varying degrees of pigment clumping in the center. Fluorescein angiography accentuated the lesion by demonstrating a sharply demarcated transmission defect, occasionally with multiple satellite lesions. The shape of the lesion matched the shape of the illuminating source of the particular operating microscope used during the surgery. The most significant risk factor associated with the production of these light retinopathy lesions was prolonged operating time. Mean total operating time for the ten patients with light retinopathy was 51 minutes longer than for those without (P less than .0001). Other significant associated factors were the presence of diabetes mellitus (P less than .03), younger age (P less than .05), and the use of hydrochlorothiazide (P less than .04).

Single-dose compared with fractionated-dose radiation of the OM431 choroidal melanoma cell line.

PURPOSE: To compare single-dose and fractionated-dose radiotherapeutic effects on choroidal melanoma cells. METHODS: We determined the effects of gamma radiation on OM431 cell survival by exposing cells to either a single 9-Gy dose or two 4.5-Gy fractionated doses at intervals of 20 minutes to eight hours. The effects of single dosing and fractionated dosing at six hours were compared at doses of 2 to 12 Gy. RESULTS: Tumor cell repair was most rapid during the first two hours. Maximum repair had occurred by six hours after radiation. Cell survival curves showed doses greater than 3 Gy of single-dose gamma radiation resulted in a greater number of cells killed than did equivalent fractionated doses. CONCLUSIONS: Ocular melanoma in vitro is relatively radioresistant to low-dose fractionated radiotherapy. High single-dose radiotherapy would be more effective but would also result in more damage to normal tissue unless more focused modalities of radiotherapy are used.