Description

This article is from the Vision and Eye Care FAQ, by grants@research.canon.com.au (Grant Sayer) with numerous contributions by others.

3.3.5 Bifocal

The different types include;

+ multifocal aspheric - light from all distances focus without interruption
by lines or zones of the lens
+ concentric - different zones of the lens for distance and/or near
+ zone based - parallel bands of focal zones for various distances
+ segmented - three basic types

(a) lens divided into two roughly equal parts like an
executive bifocal

(b) lens divided into two unequal parts with near part like
a segment of bofocal spectacles, either flat-top or
crescent shaped

(c) internally fused segment of different refractive index.

Research photos of RGP Lenses on the eye include

URL: http://www.route-one.co.uk/route-one/scotlens/

This site maintains some nice research photos of RGP lenses with conditions
such as
- Drying
- Surface Wetting
- Deposits
- Mucous Deposits

 

Continue to:

• prev: 3.3.4 Toric
• Index
• next: 3.4 Costs of Contact Lenses

Share and Enjoy

Tags

health, vision, eye care, contact lenses, spectacles, eyecare, prescriptions, sunglasses, surgery