Effect of Aging on the Normal Human Electro-Oculogram

Abstract

 

Purpose:

 

The electro-oculogram (EOG) is used to measure the light response generated by the retinal pigment epithelium (RPE), a slow voltage change of the RPE basal membrane¹. This test has clinical relevance for the assessment of retinal and RPE function, and is particularly useful in the diagnosis of Best vitelliform dystrophy. The purpose of this study was to measure the effect of aging on the EOG recorded in normal human subjects.

 

Methods:

 

The study included 121 control subjects, 62 men and 59 women, from 7 to 72 years of age, stratified by decade. All subjects underwent a full ophthalmological examination. The EOG was recorded following standard ISCEV EOG techniques¹. Five minutes of pre-adaptation (20 cd/m²), were followed by 15 minutes of dark adaptation, and by 20 minutes of light adaptation (100 cd/m²). Fast oscillations (FO) were recorded during six 2.5-minute cycles, each consisting of 75 seconds of light adaptation (100 cd/m²) followed by 75 seconds of dark adaptation. In 3 subjects, no FO could be recorded; they were excluded from analysis.

 

Results:

 

Study variables for the EOG were dark trough amplitude (DT amp), light peak amplitude (LP amp), light peak implicit time (LP time), and Arden ratio. A log transformation was used for all amplitude values. The Pearson correlation coefficient (r) was used to assess change with age. A decline in LP amp was observed, while DT amp did not change. Thus, the Arden ratio decreased significantly with age. An increase in LP time was detected. Study variables for the FO were peak-to-peak amplitude (FO amp) and phase (FO phase). An increase in phase lag was seen; FO amp showed a modest, non-significant increase.  

 

Conclusions:

 

Many parameters of the EOG change with aging, albeit to a moderate degree. This fact should be taken into consideration when determining normative reference values, and also when assessing the clinical significance of a measurement in an older individual.1. Documenta Ophthalmologica: 95: 91-92, 1998

 

Keywords: electrophysiology: clinical • aging • retinal pigment epithelium