The Pattern Evoked Electroretinogram: Origin, Characteristics and Clinical Usage

This paper consists of a literature review of the clinical observations of the pattern electroretinogram (pERG) and theories concerning its origin. Normative data are presented for subjects aged 20 to 29 years to document variations in pERG response character­istics as a function of selected stimulus parameters. Clinical cases of visual neural dysfunction are also presented to illustrate the usage of pERGs in the realm of electrodiagnostic testing. Emphasis is placed on new or complimentary information provided by these retinal potentials

Electrical Indices of Rod Dysfunction

Patients presenting with night time vision diffi­culties and a family history of retinitis pigmentosa require special testing procedures even in the absence of typical functional deficits or ophthalmo­scopically visible retinal disease. The authors discuss various theoretical aspects of electroretino­graphy and their practical clinical applications in objectively identifying the physiological defect occurring in retinitis pigmentosa

Visual Dysfunction In Recent Onset Diabetes: A Clinical Report

A clinical report is presented of a 64 year old patient with recent onset diabetes. Simple in-office test proce­dures for the detection of subtle func­tional abnormalities in the visual system are presented. Diagnostic findings are expanded by results of electrophysiological testing, and com­plemented by an investigation of vas­cular structural integrity by fluorescein angiography. The importance of an examination routine consisting of an assessment of both functional and structural aspects of the visual ele­ments typically affected by the diabetic condition is emphasized

Vascular and Neural Changes During Body Inversion: Preliminary Findings

This report examines the influence of gravity on physiological fluid pressures within the body. The interest in the influence of gravity on ocular struc­tures and function is topical not only because of the current fashion of body inversion devices as forms of exercise, but also the ocular consequence of a cephalic redistribution of blood with its subsequent effect on IOP during the micro-gravity environment of space­flight. For the ophthalmic practitioner, the effect of body orientation on intra­ocular pressure and on the blood supply to the eye is of practical importance. In this paper the influence of pre­cisely controlled body positions on the intraocular pressure, central retinal artery pressure, and systemic blood pressure is presented. Deficits in visual neural function resulting from body inversion are documented. Clinical implications of these findings are discussed