Spark in your eyes !

Spark in your eyes !

By : Dr. Prof. S.P.S. Grewal

Many of you would be surprised to know that our eyes actually run on electricity! The light waves from all the objects that we look at fall on the retina and get converted into electrical impulses that are transmitted to our brain which in turn processes the electrical impulses into an understandable view.

Retinal Electrophysiology, a study of various electrical currents generated inside our eyes, enables us to record these electrical impulses. As an expert electrician finds the expert fault by testing the various circuits, a Retinalelecto-physiologist, by performing various tests, can diagnose a problem in patients with poor vision. You get a graph for the eyes, just like the ECG.

ERG (Electroretinogram) is an indispensable tool that gives a clear assessment of the retinal function. ERG is an electrical potential generated by the retina in response to a brief flash of light. When the retina is suddenly illuminated, all of its cells are simultaneously activated and generate current. A part of this current escapes the eye through the corneas (front part of the eye). However, this current is extremely small and requires a special instrument to be recorded as ERG. The amount of generated is proportional to the functional status of the retina.

The standard ERG is the whole response evoked from the entire retina. It is not able to pick up the isolated problem localised to themacula (the central part of retina), which is the most important part of the visual function, but constitutes only1% of the total retinal surface area. Here Multifocal ERG comes to our rescue. Specialised equipments are used to measure the reaction of several areas of the retina in a single recording. This is really helpful in diseases of themacula with small or no morphological changes in the retina.

Multifocal ERG not only gives information regarding central loss of function in maculopathies, but also gives a detailed description of extent of the lesion, which is useful in case of patients with diseases such as diabetic eye disease, optic neuritis, retinal detachment, glaucoma, and multiple sclerosis.

Electrophysiolgy (used to determine presence of retinal function) is also quite useful in confirming the diagnosis of specific diseases and evaluating the progression of Age Relatedmacular Degeneration (AMD), Electrophysiology can be used for early detection of toxic retinopathies (side effect of drugs on the eyes). Electrophysiology is a useful tool that helps assess visual functions in infants, children, and uncooperative patients. All such modern tools and techniques can add a spark to your eyes. ***

Prof. Dr. S.P.S. Grewal

Grewal Eye Institute

SCO 166, Sector 9-C, Madhya Marg

CHANDIGARH - 160 014 (India)

Ph : +91-17-2747118, 5056901, 5056969

Fax : +91-172-274843

Mail : drgrewal@gmail.com

Website : www.gei.co.in