Lens shapes.pptx

FOR OPTOMETRIC OPTICS

1. LENS SHAPES

2. 1. Round

・ Most ancient shape

・ Due to round edge, nasal edge cannot be easily
determined so care must be taken while fitting that the
centration is in correct direction

・ Not advisable for toric R,

3. 2. Oval

・ Elliptical

・ Produced by cutting through a circular rod in any plane
oblique to the axis

4. 3. Pantascopic Round Oval (PRO)

ㆍ Lower half is elliptical shape with same horizontal
diameter

« Important part of evolution of modern lens shape
because it was the first step towards recognition of both
functional and ancient wear

・ Field of view is larger

5. 4. Perimetric Shape

・ On closing of eye the FOV is not symmetrical
・ Nasal side being much more restricted than temporal

6. 5. Contour Shape

« These follow both contour of the face in the region of the
eye and approximately the contour of the eyes field of
vision

7. 6. Quadra Shape

・ Different shapes and sizes

・ Have more or more than four recognizable defined sides
of shallow curvature joined by areas of shorter radium

8. 7. Pilot (Aviotar) Shape

・ Triangular characterized by a nasal cut away and
pounced fullness in the lower temporal quadrant

・ Not advisable for progressive and bifocal lens wear as
the reading portion may cut

9. 8. Half Eye Shape

・ Only near correction

10. 9. Pentagonal or octogonal

ㆍ 5-8 sides of the lens

11. 10. Sports Shape

・ Provides largest FOV