Page 119 - The Indian Optician Digital Edition July-August 2021
P. 119
CONTACT LENS
- WETTABILITY, CLEANING,
DISINFECTION AND INTERACTION
WITH TEARS
he material of contact lenses has undergone a
tremendous amount of change in the last two
Tdecades, and so has its usage. Whilst one of the
major criteria of choosing a contact lens is the comfort
it offers, research has made it more accessible and
affordable. The comfort of a contact lens heavily depends
on its wettability.
Before one delves into the details, it is important to
understand a bit more about contact lens wettability.
In simple terms, contact lens wettability is a measure
Khushbu Arora of how easily and effortlessly a liquid can spread over
Manager and Optometrist, the surface of the contact lens. This can be essentially
Arora Optical, Raipur
studied in two settings - clinically and in a laboratory.
In the former, the wettability of a material is measured
on-eye by determining the break-up time of the tear film
over the front surface of the lens. In the latter setting, it
is determined through the contact angle that provides
the inverse angle of wettability, i.e. higher wettability
corresponds through lower angles. The research on
contact lenses has been largely driven by this one factor
but there is no substantial evidence that correlates
wettability with comfort either which provides further
scope and also places power in the hands of the patient.
CLEANING AND DISINFECTING
There are two kinds of contacts - single-use and
reusable. The ones designed for single-use are contained
in a cleaning agent until removed, used and then
discarded within a certain time frame, leaving no room
for any avoidable disinfection. It is the reusable lenses
that need to be placed in lens solution for cleaning and
disinfecting purposes at the end of each day. The solution
also hydrates the lens and makes it ready for the next
| JULY-AUG 2021 | 115 CONTACTS
