Electrophysiological evidence of early functional damage in glaucoma and ocular hypertension.

Purpose: The quantification of early retinal ganglion cell damage in ocular hypertension and glaucoma.

Methods: Thirty subjects under treatment for open-angle glaucoma, 23 subjects with ocular hypertension, and 28 healthy subjects in a control group were investigated by monocular pattern electroretinogram (ERG), L&M (long and medium wavelength) cone ERG, and S (short wavelength)-cone ERG. The diagnosis of glaucoma was based on masked assessment of digital stereoscopic optic nerve head images by three glaucoma specialists.

Ganglion cell loss and dysfunction: relationship to perimetric sensitivity.

Purpose: To describe two methods of neural damage quantification from perimetric data, and to discuss their theoretical implications.

Methods: A recently published model of retinal ganglion cell (GC) receptive field density is used to obtain best estimates of the receptive fields per solid degree at each stimulus point in the 24-2 test pattern array. A method of age related change compensation is proposed and a functional relationship between perimetric sensitivity and GC survival is used for loss quantification.

Can pulsatile ocular blood flow distinguish between patients with and without diabetic retinopathy?

Purpose: Our aim was to determine if pulsatile ocular blood flow (POBF) measurements could distinguish between type 2 diabetes mellitus (DM) subjects with and without diabetic retinopathy (DR).

Methods: Ninety-eight DM subjects were recruited. POBF was measured using an Ocular Blood Flow tonometer and retinopathy was assessed using retinal digital photography.

The length of Henle fibers in the human retina and a model of ganglion receptive field density in the visual field.

An experimental study of lateral displacement of ganglion cells (GCs) from foveal cones in six human retinas is reported. At 406-675 microm in length, as measured in radially oriented cross-sections, Henle fibers are substantially longer than previously reported. However, a new theoretical model indicates that the discrepancies in these reports are mainly due to meridional differences.

Silent substitution S-cone electroretinogram in subjects with diabetes mellitus.

A defect in the blue sensitive mechanism has been reported in certain ocular and systemic diseases. For example, tritanopic colour vision defects and changes to the S-cone electroretinogram (ERG) have been demonstrated in glaucoma and diabetes mellitus. Electrophysiological methods of eliciting the S-cone ERG, however, often result in considerable L- and M-cone intrusion.