Epidemiology and aetiology of presbyopia and refractive errors
11 / 2004 - 09 / 2008
OBJECTIVES: The optical system of the eye consists of the cornea and lens, which refract the light entering the eye to obtain sharp vision. The lens is able to change its shape, which allows focusing at various distances (accommodation). Unfortunately, this ability diminishes with age (presbyopia); reading glasses generally become necessary at the age of 45. Surprisingly, for the human eye, there is still a lack of reliable data describing its refractive properties. This is particularly true for the inner structures of the eye (posterior corneal surface and the lens). The purpose of this study is to measure the shape of the cornea and lens as a function of accommodation, age, and refractive error. This gives more insight in the origin of presbyopia and development of refractive errors. METHODS: The shape of the lens and cornea (shape, thickness, radius), eye length, and optical properties of the whole will be measured by three objective methods: 1) slit-lamp Scheimpflug photography; 2) partial coherence interferometry; and 3) aberrometry. Biometric data is collected on 200 eyes in subjects ranging in age from 18 to 70 years. This combination of techniques allows a complete description of the optics of the eye.