In the 1940ΓÇÖs haptic lenses were fitted with minimal
clearance of the cornea. The lens still rested on
the scleral but there was only a thin tear
layer under the lens. These lenses were
called fluidless lenses since fluid did not
have to be put in the lens prior to
placement on the eye. A hole (called an
aperture or fenestration) was put in the
lens to allow exchange.
The fluidless lenses allowed longer
wearing times since there was more
exchange of the fluid and more
oxygen reached the cornea. Lens
fitting was exacting and time consuming
because of the necessity of matching the
shape of the eye.
(Later modules will cover these lenses in more detail-they are still used on a limited basis for special situations or as cosmetic shells to cover damaged eyes).