Metabolic Disorders: Optic Fundus Photography
Optic fundus photography is performed on conscious animals using a Kowa Genesis small-animal-fundus camera modified according to Hawes et al. (1999). Intraperitoneal injection of fluorescein permits the acquisition of direct light fundus images and fluorescent angiograms for each examination. These non-invasive tests detect clinically important phenotypes in the retina such as progressive retinal degenerations and proliferative retinopathies. Mutations in several genes, such as beta-subunit of rod phosphodiesterase present with comparable fundus changes in both mice and humans (Hawes et al., 1999; McLaughlin et al., 1993). In addition to direct ophthalmological changes, this test can detect retinal changes associated with systemic diseases such as diabetes and atherosclerosis (Kim et al., 2004; Kimble et al., 2005).
Qualitative results are presented as digital images in comprehensive data packages. Reference images from wild type mice are also provided.
Image illustrates fundus of mutant (left) and reference wild type (right) mice. Images were taken with a Kowa Genesis small-animal-fundus camera (Kowa Optimed, Inc; Torrance, CA)
Displayed below is a sample graph of quantitative data form optic fundus images are presented. In comprehensive phenotypic data packages graphs are interactive. Raw or calculated data and statistics can be seen by clicking on points in the graph.
Figure illustrates artery to vein ratio in retina of mutant mice. Artery/vein ratios of wild type littermates (green circle), homozygous (red diamond), and recent historical wild type (purple line) mice are plotted against long-term historical values (± 2 standard deviations) for wild type animals (green shading). Recent wild type values are calculated from data collected within 60 days of current measures and long-term historical values are derived from data collected on more than 10,000 wild type mice.
Hawes NL, Smith RS, Chang B, Davisson M, Heckenlively JR, John SW. (1999) Mouse fundus photography and angiography: a catalogue of normal and mutant phenotypes, Mol Vis, 5:22.
Kim SY, Johnson MA, McLeod DS, Alexander T, Otsuji T, Steidl SM, Hansen BC, Lutty GA. (2004) Retinopathy in monkeys with spontaneous type 2 diabetes, Invest Ophthalmol Vis Sci, 45:4543-4553.
Kimble JA, Brandt BM, McGwin G Jr. (2005) Clinical examination accurately locates capillary nonperfusion in diabetic retinopathy, Am J Ophthalmol, 139:555-557.
McLaughlin ME, Sandberg MA, Berson EL, Dryja TP. (1993) Recessive mutations in the gene encoding the beta-subunit of rod phosphodiesterase in patients with retinitis pigmentosa, Nat Genet, 4:130-134.