Ocular fluorophotometry in the normal- and diabetic monkey.

Normal- and diabetic rhesus monkeys without retinopathy demonstrable by ophthalmoscopy or fluorescein angiography were examined with ocular fluorophotometry to detect alterations in their blood-ocular barriers. All vitreous fluorophotometry values were corrected for fluorescence attributable to background levels and then normalized to a blood fluorescein level of 10 micrograms ml-1. Reproducibility studies demonstrated an average coefficient of variation of 0.17 for all animals combined. Insulin-dependent monkeys, both pancreatectomized and streptozotocin-treated, demonstrated significantly higher posterior vitreous fluorescence levels than either control animals or monkeys treated with streptozotocin that were not insulin-dependent. These results cannot be attributed to differences in fluorescein binding or to vitreous abnormalities. However, 14 out of 24 (58%) of the insulin-dependent animals exhibited posterior vitreous fluorescence values within two standard deviations of the control mean. No correlation was apparent between the vitreous values and age or duration of treatment. No difference in anterior chamber concentrations was found between groups after correction. Our results indicate that alterations in blood-retinal barrier can occur in insulin-dependent diabetic monkeys before development of retinopathy.

Coloboma of optic nerve associated with serous maculopathy. A clinicopathologic correlative study.

A rhesus monkey with a congenital coloboma of the optic nerve head associated with serous macular detachment underwent intravenous (IV), intrathecal, and retrobulbar fluorescein angiography. No fluorescein leaked beneath the serous detachment after IV or intrathecal injection, although the retrobulbar injection caused a bolus to extravasate from the margin of the optic nerve coloboma, drifting toward the macular region temporally. Histopathologically, glial tissue replaced optic nerve axonal bundles in the temporal coloboma. The intermediary tissue of Kuhnt was disrupted, and fluid from the retrobulbar space diffused into the subretinal space temporally, where a localized retinal detachment extended from the optic nerve to the macula. Subretinal fluid in the macula associated with optic nerve coloboma might derive from (1) fluid perfusing into the retrobulbar space from surrounding orbital tissue, (2) peripapillary choriocapillaris, or (3) CSF.

Birdshot retinochoroidopathy.

Nine patients had birdshot retinochoroidopathy. Associated ophthalmologic findings included rhegmatogenous retinal detachment, rubeosis iridis, glaucoma, and a high incidence of disciform macular degeneration. Four patterns of birdshot spot distribution were noted on fundus examination. Immunologic studies showed a significantly elevated percentage of EA rosettes and an elevated C4 complement level. Electroretinograms showed b-wave amplitude reduction, with a disproportionate implicit time prolongation. The etiology of this syndrome remains unknown.

Intraocular granulomas associated with tuberculosis in primates.

Intraocular granulomas associated with tuberculosis were observed in 2 subhuman primates (Ateles geoffroyi and Macaca mulatta). Bacterial cultures from lung tissues at the time of necropsy confirmed the presence of Mycobacterium bovis and M tuberculosis, respectively. The absence of generalized clinical signs in spite of systemic dissemination of the organisms in these cases and the public health significance of tuberculous infections emphasize the importance of proper observation and diagnostic procedures in primate colonies and display collections.

Macular lesions in blacks with the presumed ocular histoplasmosis syndrome.

Six black patients had fundus lesions diagnostic of the presumed ocular histoplasmosis syndrome. All patients had peripapillary changes or peripheral punched-out chorioretinal lesions, or both. Five of the six had macular subretinal neovascularization, disciform scarring, or an atrophic macular lesion, and one patient had a macular hole; four of five patients tested had a positive histoplasmin skin test. The macular involvement was bilateral in three of the six cases. HLA B-7 was present in one of four patients who had HLA typing. Macular involvement can occur in blacks with the presumed ocular histoplasmosis syndrome.

Bilateral cytomegalovirus panuveitis after high-dose corticosteroid therapy.

A 30-year-old previously healthy woman who recieved immunosuppressive doses of corticosteroids developed an unusual culture-proved cytomegalovirus panuveitis bilaterally. The atypical clinical course was marked by bilateral exudative detachements with minimal evidence of retinitis. Any patient receiving blood transfusions and immunosuppressive doses of corticosteroids is potentially at risk for developing ocular cytomegalovirus infection, and the clinical presentation of the ocular infection may be atypical.

Early detection of retinal involvement in diabetes by vitreous fluorophotometry.

Vitreous fluorophotometry is a new quantitative method for evaluation of the blood-retinal barrier (BRB). The application of this method to a series of diabetic patients with apparently normal fundi revealed the presence of a significant breakdown of the BRB in the early stages of retinal involvement in diabetes. This alteration of the BRB appears to be the earliest clinically detectable change to occur in the retina in diabetes. Higher vitreous fluorophotometry values, indicating a more marked breakdown of the BRB, occurred in patients who were under worse metabolic control. Higher vitreous fluorophotometry values were also associated with the development of visible retinal lesions.

Vitreous fluorophotometry evaluation of xenon photocoagulation.

An abnormal increase in the permeability of the outer blood-retinal barrier was induced in the eyes of adult pigmented rabbits after retinal xenon arc photocoagulation. The alteration of the blood-retinal barrier, which was assessed by vitreous fluorophotometry after systemic administration of sodium fluorescein, followed a well-defined pattern. Higher values, which were recorded during the first three days after photocoagulation, recovered progressively afterward. The permeability of the blood-retinal barrier returned to near-normal levels between 10 and 14 days after photocoagulation. A direct correlation was observed between higher initial values and heavier photocoagulation.

Ultrastructure of the hyaloid vasculature in primates.

The histology and ultrastructure of the hyaloid vascular system was studied in 16 monkeys, ages 85 days in utero to 3 years old. The well-developed hyaloid artery is identifiable ultrastructurally as an arteriole consisting of a nonfenestrated intima, a multilayered smooth muscular media, a connective tissue adventitia, and a perivascular sheath. By the fourth week after birth, the vessel walls appear hyalinized and acellular; the lumen is occluded by a thrombus. The time of the complete disappearance of the hyaloid artery varied considerably in individual monkeys; remnants of the hyaloid artery were often present on the disc (Bergmeister's papilla) in adult life. The vasa hyaloidea propria and tunica vasculosa lentis are small branches of the hyaloid artery which fill the primary vitreous. Ultrastructurally, they are Type A-1-alpha capillaries having a nonfenestrated endothelium, incomplete pericyte layer, and basement membranes surrounding each. Fluorescein angiography of several newborn monkeys revealed nonleakage of dye from the hyaloid artery and its branches, thus correlating with the presence of endothelial tight functions.

Hyaloid vascular remnants in human neonates.

A consecutive series of 226 infants was examined within 36 to 48 hours of birth using direct and binocular indirect ophthalmoscopy. Hyaloid vessel remnants were observed in over 90% of infants of less than 36 weeks gestation and in over 95% of infants weighing less than 5 lbs at birth. The majority in these groups were complete remnants. The number of complete remnants in preterm and low birth-weight infants was significantly higher than previously reported. The distinctive and orderly changes in the premature eye were suggested as a possible method of gestational assessment.

Experimental inhibition of prostaglandin-like inflammatory response after cryotherapy.

To determine the effect of aspirin as an inhibitor of the prostaglandin-induced inflammatory reaction that follows cryotherapy, 12 rabbits were pretreated with aspirin and 12 were controls. The aspirin-pretreated animals showed less inflammatory reaction after cryotherapy and significantly less protein in the aqueous humor than did the control animals (P less than .01). We believe that the conjunctival hyperemia and chemosis, and the increase in protein concentrations in the aqueous humor that follow cryotherapy, are prostaglandin-related, because pretreatment with aspirin inhibited these phenomena.

Octafluorocyclobutane in vitreous and aqueous humor replacement.

Vitreous replacement with air, pure octafluorocyclobutane (C4F8), and mixtures of 40% C4F8 and 60% air was done in owl monkeys to determine ocular toxicity and duration of gas within the vitreous compartment. Large volumes of gas mixture and pure C4F8 caused posterior subcapsular cataract formation. Pure C4F8 expands in the vitreous within 24 to 48 hours. A 1.0-ml mixture of 40% C4F8 and 60% air lasted 12.7 days and did not cause ocular changes. However, anterior chamber aqueous replacement with pure C4F8 or gas mixture resulted in cataract production. Twenty-four and fourty-eight hours after injection of 0.1-ml pure C4F8 in the vitreous of experimental rabbits, presence of oxygen, nitrogen, and carbon dioxide was shown by gas chromatographic analysis. This finding supports the hypothesis of volume expansion secondary to diffusion of above-mentioned gases inside the C4F8 gas bubble.

Clinical trail of intravitreal C F in retinal detachment surgery.

A mixture of 40% octafluorocyclobutane (C4F8) and 60% air was used clinically in eight patients with long-standing retinal detachment. In seven cases the retina reattached after intravitreal injection of C4F8 and intrascleral diathermization of the retinal tear. The one failure was due to massive vitreous retraction and preretinal proliferation prior to the surgery. Except for a slight postoperative iritis when 4 cc of gas lasted for 12 to 30 days after intravitreal injection. On the basis of this and our previous studies, we recommend the use of C4F8 in retinal detachment surgery.