The interaction of infrared light with the human ocular fundus, particularly sub-retinal structures, was studied in vivo. Visible and infra-red wavelengths and a scanning laser ophthalmoscope were used to acquire digital images of the human fundus. The contrast and reflectance of selected retinal and sub-retinal features were computed for a series of wavelengths or modes of imaging. Near infrared light provides better visibility than visible light for sub-retinal features. Sub-retinal deposits appear light and thickened; the optic nerve head, retinal vessels, and choroidal vessels appear dark. Contrast and visibility of features increases with increasing wavelength from 795 to 895 nm. Optimizing the mode of imaging improves the visibility of some structures. This new quantitative basis for near infrared imaging techniques can be applied to a wide range of imaging modalities for the study of pathophysiology and treatment in diseases affecting the retinal pigment epithelium and Bruch's membrane, such as age-related macular degeneration.

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In a cross-sectional survey of 86 elderly persons, it was observed that subjects with elevated plasma alpha-tocopherol levels had depressed plasma gamma-tocopherol. Tocopherols were measured by both reverse-phase and normal-phase high performance liquid chromatography (HPLC). When eight human volunteers (age range 30-60) were given 1200 IU of all-rac-alpha-tocopherol daily for 8 wk, plasma gamma-tocopherol and beta-tocopherol decreased in all subjects. After supplementation, gamma-tocopherol values were typically 30-50% of initial values, and alpha-tocopherol values were typically 200-400% of initial values. These results suggest that intestinal uptake and/or plasma transport make more efficient use of alpha-tocopherol than of gamma- or beta-tocopherol. Moreover, the results indicate that the ratio of gamma- to alpha-tocopherol in plasma would be a more satisfactory index to measure compliance in trials involving supplementation with alpha-tocopherol.

To understand the natural history of retinal pigment epithelial (RPE) detachments (PEDs) associated with drusen, we retrospectively reviewed 125 PEDs that had not undergone laser treatment over an average follow-up period of 28 months. We identified six types of RPE detachments: pseudo-vitelliform, confluent drusen, serous, vascular, and hemorrhagic lesions as well as PEDs associated with a retinal vascular abnormality. We correlated the type of detachment with visual acuity and anatomic outcome. The poorest results were obtained for PEDs associated with neovascularization (vascular, hemorrhagic, and retinal vascular abnormality types). Eyes presenting with pseudo-vitelliform lesions or confluent drusen had the best visual prognosis and anatomic results. Obvious subretinal new vessels developed in 16 (34%) of the serous PEDs over an average follow-up period of 25 months. Subretinal neovascularization was rare in the pseudo-vitelliform and confluent drusen groups. The proposed classification system may be useful in predicting the natural course of PEDs.

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The bidirectional laser Doppler technique and monochromatic photography were used to measure the absolute blood flow rate in the majortemporal retinal arteries in seven patients foliowing unilateral scleral buckling and encircling procedures, and in two patients before and after removal of scleral buckling elements. In the seven patients who had undergone uncomplicated scleral buckling procedures the arterial flow rates were on average 50% lower (p=0-01) in the surgicaily treated eyes than in the contralateral eyes. Removal of scleral buckling elements in two patients produced increases of 73% and 44% in arterial blood flow rates.In the current study we used the newer bidirectional laser Doppler technique and monochromatic retinal photography to measure for the first time absolute retinal blood flow rates in seven patients who had undergone unilateral scleral buckling procedures for the repair of retinal detachment. Specifically we compared the blood flow rates measured in retinal arteries of surgically treated eyes with the flow rates measured in corresponding arteries in fellow eyes. In two additional patients who experienced complications after scleral buckling procedures absolute blood flow rates were measured in retinal arteries before and after removal of the buckling elements.

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