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Posters
December 2002
COMPARISON OF BIOMICROSCOPY SIGNS
BETWEEN NEW AND EXPERIENCED CONTACT LENS WEARERS WHEN DISPENSED
IN A HIGH DK FLUOROSILICONE SOFT CONTACT LENS.
Bill Long BS, MBA, FAAO CIBA Vision Corp., Scott Robirds OD,
FAAO, Tim Grant BOptom, FAAO, CIBA Vision.
Purpose:
Changes in biomicroscopy signs have
been reported with soft contact lens wear. These reports
have been with low Dk lenses. With the introduction of highly
oxygen permeable soft contact lens materials (high Dk lenses),
there is an opportunity to examine the contribution of increased
oxygenation to corneal health via biomicroscopy. The purpose
of this trial was to determine the impact of high Dk extended
wear on corneal health via biomicroscopic signs. We analyzed
data from a multi-national, in-practice clinical trial of
patients dispensed for up to 30 night extended wear of a
high Dk (Dk/t=175) fluorosilcone soft contact lens (lotrafilcon
A, CIBA Vision USA).
Method:
321 patients in Argentina,
Brazil, and Spain were dispensed in a 6 month, in-practice
clinical trial. 273 (85%) were experienced contact lens wearers
and 48 (15%) were new contact lens wearers. Biomicroscopy
signs were graded at dispensing, 1 week, 1 month, 3 months
and 6 months using a 0 (absent) to 4 (severe) scale with integer
steps. All biomicroscopy signs for both experienced or new
wearers at all visits below 0.5. Biomicroscopy signs were
analyzed individually, overall and grouped into sings indicating
hypoxic, vascular, and surface response and compared using
Student's unpaired t-test.
Results:
At baseline, experienced
wearers showed higher average signs than new wearers for overall
average (p=0.0001), hypoxic (p=0.0002), vascular (p=0.0014)
signs. At 6 months differences between experienced and new
wearers were very minimal although statistically significant
differences were found overall (p=0.0385) and surface (p=0.0004)
signs. The signs for experienced wearers improved from baseline
to 6 months. On average, signs for new wearers were lower
than signs for experienced wearers throughout the trial.
Conclusions:
The results indicate
that there is an improvement in corneal health as seen in
biomicroscopy signs among experienced wearers and that with
new wearers minimal changes in corneal signs occur compared
to baseline observations.
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