Study of the Effects of Aging, Refraction and Intraocular Pressure Levels on Retinal Nerve Fiber Layer Thickness of Normal Healthy Eyes

Abstract

Glaucomatous optic neuropathy (GON), clinically characterized by progressive visual field defects that correspond with glaucomatous optic disc changes, is known as one of the major causes of irreversible blindness worldwide (Quigley, 1999). Thus far, there is no known cure for GON. Thus, early diagnosis and treatment to slow down the disease progression is considered of most importance. To diagnose earlier stages of GON, a sensitive and reliable methodology to detect the specific glaucomatous optic disc changes required. To this point, retinal nerve fiber layer (RNFL) thickness measurements by optical coherent tomography (OCT) has been widely utilized (Bowd et al., 2000; Katai et al., 2003). However, the optic disc appearance is quite variable within even healthy populations. In fact, recent studies have revealed that its incidence exclusively varies with races, ages and others, and therefore, these factors should be taken into account to perform better analyses through OCT (Katai et al., 2006). The purpose of the present study is to investigate the effects of aging, refraction, and intraocular pressure levels on RNFL thickness. To do so, the eyes of healthy Japanese individuals were evaluated and compared with those of Europeans.