Optics of Contact Lenses |
Contents
REVISION OF ELEMENTARY OPTICS | 1 |
TO DETERMINE THE VERTEX POWERS OF A GIVEN LENS | 9 |
THEORY OF AFOCAL LENSES | 21 |
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Common terms and phrases
afocal ametropia angle apical clearance applies approximately assumed astigmatism auxiliary axis back vertex power basis blurred calculation cent centre thickness Chapter comparison computing contact lens system corneal vertex correction corresponding crystalline lens curvature curve denotes determined difference dioptres distance effect entrance pupil equal equation equivalent power error example expression eye's F₁ F₂ figures fitting fluid focal length formed formula give given graph Hence hypermetropia incident increase inner optic radius keratometer L₁ lenses light liquid lens means measured method metres neutralising object obtained ocular accommodation ocular refraction orthodox spectacles parallel pencil placed plane portion position possible posterior power F previously principal point prismatic effect purely radii ratio reading reduced reference refractive index Relative Spectacle Magnification represents result retinal image schematic eye seen shown shows simple spectacle lens Spectacle Magnification spectacle refraction surface power Taking trial vergence