Question

What is The different components of the schematic eye ( compare and contrast the schematic eyes).

Answer 1

A schematic eye is a mathematical or physical model that represents the basic optical features of the real eye.

Dimensions of the reduced schematic eye, defined by the anterior corneal surface (P), the simplified nodal point of the eye (N), and the fovea (F'). The distance from the simplified nodal point to the fovea is 17.0 mm, and the distance from the anterior corneal surface to the nodal point is 5.6 mm. The refractive index for air is taken to be 1.000, and the simplified refractive index for the eye (n') is 1.333. The refractive power of this reduced schematic eye is 60.0 D, with its principal plane at the front surface of the cornea.

Nodal point :
The average eye has an axial length 22.6 mm and the index of refraction of the ocular media is 1.333, indicating a refractive power of 1.333/0.0226 = 59 D. The nodal point of this representative eye is located 17 mm in front of the retina.

Measurement of ocular wavefront aberration is becoming a popular clinical technique due to recent technical advances and an increasing awareness of its potential for practical application in the fields of surgical and optical refractive correction. In addition, information about the status of peripheral refraction determined from ocular wavefront aberrations is now being used to monitor the progression of myopia and other refractive errors in children, and as a basis for the study of the process of emmetropization. Several finite, anatomically accurate, wide-angled, model eyes have been proposed previously in an effort to produce a schematic eye that accurately reproduces vision under different practical circumstances. This compares these models in terms of their wavefront aberration, image quality metrics and peripheral refraction profiles and contrasts these with data from real eyes to assess their relative utility.