The soft lens, when larger than the corneal diameter,
acts as an occlusive membrane. The manner in
which it prevents water and gas movement have
been extensively investigated over the past decade.1-3
The relationship between gas movement and the
permeability of the lens material has also been
investigated. The workers in this field of study
recognise that lens form, particularly thickness,
temperature, water content, and the physicochemical
properties of the plastic determine the gas transmissibility
of the lens.