Page 216 - PowerPoint 演示文稿

206 Ophthalmic Lenses

time comfortable close and middle distance vision. They can be coated with
anti-reflection coating also. The right and left lenses are symmetrical and
the pupil centre has to be at the lens centre.

ENHANCED NEAR VISION LENS

In an age powered by microchips and computers, time spent working on
computers is rapidly growing. Now, presbyopes who spend time on
computers to communicate with the world and to carry out their
occupational needs can turn to new type of lens in the form of enhanced
near vision lens for the most efficient solution to their visual demands for
near vision as well as intermediate vision. Designed for near and
intermediate vision, this lens offers maximum comfort and wider field of
vision at near and intermediate both. These lenses have become superior
alternative to the near vision lenses and are very good for specific visual
needs. These lenses are suitable for first time presbyopes, single vision users
looking for enhanced near vision and also bifocal users who wants an
additional pair for near vision work.

Fig. 15.2: Enhanced near vision lens

Dispensing criteria
Enhanced near vision lenses are fitted to the near vision prescription by
taking near vision monocular pupillary distance and height. It is usually 3
to 5 mm below the pupil centre. In most cases this corresponds to frame
datum line as shown in the Figure 15.3.