Advanced Vision Analysis

In most basic terms, visual loss can be categorized as either optical or retinoneural.

Optical sources involve any obstruction or scattering of light along the clear pathway through the eye. Such problems as opacities of the cornea, cataract or vitreous opacities would be examples of optical sources vision loss. The effect of optical sources on overall vision loss can be objectively determined by using wavefront aberrometry using the i-Trace aberrometer and glare disability testing using the C-Quant psychometric glare tester.

Retinoneural sources involves impairment of the function of the electrical events involved in reception of light in the retina where an electrical signal is formed, transmission of the electrical impulse through the pathways (optic nerve, optic chiasm, optic tract and radiations) to the brain and finally the areas of creation of the sense of sight in the visual part of the brain (posterior cortex) with integration and interpretation elsewhere throughout the brain.

At VRV we study the impairment of the electrical signal creation and its transmission to the brain with pattern ERG and visually evoked potential [VEP] using the Diopsys instrument. This can be invaluable in finding earliest evidence of vision loss in condition such as glaucoma or retinal toxicity, as may occur with the use of certain drugs such as hydroxychloroquine (Plaquenil) frequently used in long-term management of rheumatological conditions.

The combined use of optical and retinoneural assessment can permit more accurate localization of the source of vision loss.