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Sports Lenses 195

The solution to this is especially designed spectacle lenses which are
individually manufactured to meet most prescription needs in terms of
the following with the aim of fitting the lenses directly into the frames:
1. The base curve
2. The dioptric power
3. The cent ration.
So, while dispensing sports lenses following specifications must be
considered:
1. Prescription (Spherical, Cylindrical, Axis, Prism)
2. Monocular P.D and fitting height.
3. Lens data:
a. Refractive index of the lens
b. Base curve of demo lens.
c. Diameter of the blank.
4. Frame data:
a. Eye shape
b. Bridge size
c. Horizontal inclination of the frame or dihedral angle.
From this information, sports software calculates an aberrationally corrected
dioptre effect and optimizes the centering data to provide wider peripheral
field of view and clear vision throughout the lens size.

HORIZONTAL INCLINATION

Horizontal inclination is measured by drawing a tangent to the optical
centre of the lens and noting the angle it makes with the front plane of the
frame. As it is clear from Figure 14.3 that the visual axis of a sports frame
does not correspond to the optical axis of the lens and this is really the
reason why we need to make compensations for sports lens dispensing.
There will be some adjustments in the dioptric power and/or cylinder with

Fig. 14.3: Horizontal inclination