Abstract
Purpose: :
The compatibility of various silicone hydrogel lens brands with marketed multi–purpose solutions (MPS) was evaluated based on corneal staining after 2 and 4 hrs of lens wear and subjective comfort responses.
Methods: :
A series of 1–week clinical studies were conducted over 5 months at one research site, using a double–masked, randomized, crossover design. Nine to fourteen asymptomatic daily–wear soft contact lens wearers wore silicone hydrogel contact lenses for 2 and 4 hours.. A recent study suggests the optimal time to measure corneal staining appears to be 2–4 hrs after lens wear. Prior to wear, new lenses were pre–soaked in Alcon OPTI–FREE® EXPRESS® (Polyquaternium–1), B&L ReNu® MoistureLocTM (Alexidine), CIBA Vision AQuify® (Polyhexanide), or AMO Complete® MoisturePLUSTM (Polyhexamethylene biguanide) for 12 hrs overnight in preconditioned lens cases. At baseline, 2–hr, and 4–hr visits on the same day, subjects rated comfort and the cornea was examined with fluorescein and a yellow filter. The cornea was divided into five zones and staining was evaluated according to type (0–4) and area (0–100%).
Results: :
All corneal staining type was micropunctate. The worst solution combinations for each lens brand, with respect to staining area, were Complete MoisturePLUS/ PureVision at 2 hrs (38%) and 4 hrs (33.7%), AQuify/PureVision at 2 hrs (21.3%) and 4 hrs (11.7%), MoistureLoc/Oasys at 4 hrs (8.2%), MoistureLoc/PureVision at 4 hrs (8%), MoistureLoc/O2Optix at 4 hrs (7.4%), and AQuify/O2Optix at 2 hrs (7.1%). OPTI–FREE had consistently lower staining area averaging 3.5% at 2 hrs and 3.8% at 4 hrs across all silicone hydrogel lens brands. Subjective ratings of comfort showed a moderate, inverse correlation (r = –0.44) with staining results at 4 hrs.
Conclusions: :
This data indicates that certain combinations of silicone hydrogel lenses and MPS may be incompatible and cause clinically meaningful corneal staining during the first few hours after insertion. Practitioners who dispense these lens types and solution combinations should be aware of the potential ocular response and consider the time of day the patient is examined.
Keywords: contact lens • cornea: clinical science • cornea: epithelium