Lutetium texaphyrin (Lu-Tex): a potential new agent for ocular fundus angiography and photodynamic therapy.

PURPOSE: To investigate the suitability of lutetium texaphyrin (lu-tex) as a fluorescence imaging agent in the delineation of retinal vascular and choroidal vascular diseases. The utilization of an efficient fluorescent molecule that is also a photosensitizer represents a unique opportunity to couple diagnosis and therapy. METHODS: Fundus fluorescence angiography comparing lu-tex (motexafin lutetium, Optrin, Pharmacyclics Inc, Sunnyvale, California) with the conventional angiographic dyes, sodium fluorescein, and indocynanine green (ICG), was performed on the eyes of normal and laser-injured New Zealand white rabbits. Plasma pharmacokinetic data and plasma protein binding were assessed in addition to light microscopy of the retina in both imaged and laser-injured eyes. RESULTS: Normal retinal and choroidal vasculature was well delineated by lu-tex angiography. Experimentally induced choroidal and retinal vascular lesions were enhanced by lu-tex and demonstrated different staining patterns than fluorescein or ICG, particularly at the margins of the lesions. Lu-tex cleared rapidly from the plasma, with 39.7% bound to the high-density lipoprotein (HDL) fraction while 15.8% was bound to the low-density lipoprotein (LDL) fraction. No evidence of retinal toxicity after dye administration was observed by either ophthalmoscopy and fundus photography or by light microscopy. CONCLUSION: Lu-tex angiography is a potentially valuable method for retinal vascular and choroidal vascular evaluation, and it has advantages over fluorescein and ICG angiography. The same agent could conceivably be used for both the identification of abnormal vasculature and subsequent photodynamic treatment.

Repeatability of the glaucoma-scope measurements of optic nerve head topography.

The Glaucoma-Scope is designed to measure the topography of the optic nerve head. Depth measurements are reported as a grid of cells where each value represents the average depth of an area 55 +/- 100 mum in size. The Glaucoma-Scope was tested on 10 normal and 18 glaucomatous subjects, >40 years of age. Two separate visits were simulated for each patient. To estimate measurement variability, depth values were analyzed in groups of 25 cells, comprising "areas of interest." A components of variance analysis was used to compare the variability of the difference between the depth of an area measured at the first and second visits. The analysis yields within visit standard deviation of the difference between depth measurements taken within the same visit (Sw), the standard deviation of the difference between depth measurements taken at separate visits (Sb), and the total standard deviation of the difference between depth measurements (Sd). For flat areas outside the optic nerve head, Sd = 11.68 mum. For flat areas within the optic nerve head, Sd = 17.91 mum. For areas at the bottom of the cup, which includes sloped areas, Sd = 32.01 mum. For sloped areas within the optic nerve head, Sd = 20.78 mum. For areas over a vessel, Sd = 34.76 mum. The mean standard deviation of a single pixel in the Glaucoma-Scope measurement is 15.42 mum. The Glaucoma-Scope measurements are highly reproducible for both healthy and glaucomatous subjects. Local variability in depth measurements should be considered when evaluating change in optic nerve head topography.

Digital indocyanine-green angiography in chorioretinal disorders.

The authors performed digital indocyanine-green angiography in 37 patients with chorioretinal disorders. Eighteen patients had choroidal neovascularization, 7 patients had atrophic age-related maculopathy, and 12 patients had uncommon choroidal and retinal disorders. A Topcon indocyanine-green camera was integrated with a digital (1024-line resolution) angiography system. Compared with conventional video or photographic indocyanine-green angiography, this technique offers enhanced image resolution, the possibility of direct qualitative comparison with fluorescein angiography, image archiving, hard-copy generation, and tracing capabilities to plan laser treatment strategies and monitor the adequacy of laser therapy after surgery.