PURPOSE Disruption of widely expressed essential genes in mice often leads to embryonic or neonatal lethality. To circumvent this problem and dissect gene functions in the cone photoreceptors, we elected to generate cone photoreceptor specific cre transgenic mice. METHODS Transgenic mice expressing Cre recombinase directed by the human red/green pigment (HRGP) gene promoter were generated. Ca...

PURPOSE To develop a contact lens electrode with a built-in blue light-emitting diode (LED) to record the electroretinogram from short-wave sensitive-cone (S-cone) electroretinogram (ERG) in humans. METHODS The ERG was recorded using the blue LED (450 nm) built-in electrode under a yellow background illumination from a slide projector in five normal subjects, a patient with blue cone monochro...

PURPOSE To evaluate the effects of selective rod and/or cone loss on frequency-domain optical coherence tomography (fdOCT) measures of photoreceptor structure in patients with retinal degenerative diseases. METHODS Six patients with cone dystrophy (CD) and eight patients with retinitis pigmentosa (RP) were recruited from the Southwest Eye Registry on the basis of diagnosis and ERG findings. f...

We study the Zariski tangent cone TX π −→ X to an affine variety X and the closure TX of π−1(Reg(X)) in TX . We focus on the comparison between TX and TX , giving sufficient conditions on X in order that TX = TX . One aspect of the results is to understand when this equality takes place in the presence of the reducedness of the Zariski tangent cone. Our other interest is to consider conditions ...

OBJECTIVES To describe the clinical, perimetric, and electroretinographic (ERG) results of 4 patients with cone dysfunction following irofulven treatment including the histopathologic and immunocytochemical features of one patient's retinas. DESIGN Observational case series. METHODS The patients were examined clinically, including perimetric and ERG evaluations. Eyes from patient 1 and heal...

The ganzfeld-evoked electroretinogram (ERG) is the most effective measure of the mass electrical response of cones and rods; however, all variables affecting the various components of the ERG have not been identified. The scotopic b-wave amplitude has been appreciated to be age-dependent, but little or no information exists in the literature regarding age dependency for other components. Linear...

Estimates of the density spectrum of the macular pigment (Wyszecki G, Stiles WS. Color Science: Concepts and Methods. Quantitative Data and Formulas. 1st ed. New York: Wiley, 1967); (Vos JJ. Literature review of human macular absorption in the visible and its consequences for the cone receptor primaries. Institute for Perception. Soesterberg, The Netherlands, 1972) are partially based on the di...

The cone electroretinogram has been examined at different levels of ganzfeld adaptation in normals and subjects with retinitis pigmentosa (RP). As light adaptation increases, the amplitude and time course (measured as b-wave implicit time) of the cone ERG decrease in both normal and RP subjects. The same level of light adaptation, however, decreases the amplitude and the implicit time more in n...

Rod amplitudes as a function of retinal illuminance were analyzed by determining the parameters of the best fit Naka-Rushton function for 15 normal subjects, 25 patients with rod-cone degeneration, and 10 patients with cone-rod degeneration. Rod b-wave implicit times were analyzed by determining the best linear fit to log retinal illuminance. Retinal illuminances necessary for a criterion b-wav...