CONTACT LENSES
Cornea-Contact Lens Interaction in the
Aquatic Environment
Mark S. Brown, MD
Irwin M. Siegel, OD, PhD
Purpose: A large population of ametropic scuba divers wear contact
lenses.Wediscussopticsandcornealphysiology,aswell asthetypes
of contact lensesthat are appropriatefor underwateractivities.
Methods We reviewed an extensive body of literatire to formulate
guidelines to aid the contact lens fitter in satisfying individual sport
diver's needs.
Results: Optical factors such as image displacement and light wave-
lengthshiftsrequirethatcontact lensesfor underwaterusebesuitably
modified. Underwater images appear nearer and larger (requiring
greater accommodation) and are made up almost exclusively of the
short wavelength end of the spectrum. Correction of presbyopia, in
particular, is influenced by these factors. For example, presbyopic
contact lens-correctedmyopesrequiregreater near adds underwater
than when viewing the same objects in air. In general, presbyopes
shouldconsidermonovisioncorrectionto facilitateunderwatervisual
tasks.Althoughdiverswearingrigidgaspermeablecontact lensesrun
the risk of morecorneal problemsthan soft lens wearers if conserva-
tive ascents are not adhered to, there are no compelling reasons to
change lens types in patients who are already fully adapted. Soft
contacts, while very stableonthe eyeduring diving, present agreater
risk of lens contaminationby sea or fresh water exposure. However,
the latter problems are easily overcome by using disposable soft
lenses.
Conclusion: In this paper, we present several suggestions for lens
material,modificationsrequiredfor underwaterametropiacorrection,
and wearing modalitiesfor the sport divers. An understandingof the
dramatic changesthat impact the propertiesof light, corneal physiol-
ogy, and visual perception which accompany the diver below the
surfacewill enablethe contact lens fitter to design a lens appropriate
to the needs of the individualpatient.
Introduction
The underwater scene observedby the s