Evaluation of Corneal Staining Related to Multi-Purpose Disinfecting Systems

Purpose: To evaluate an objective method of measuring corneal staining and to compare the clinical performance of three commonly used multi-purpose solutions.

Methods: Corneal staining recorded on video and digitally analyzed using an image processing program to calculate total area of staining(mm2) from number of spots and average area per spot.

Staining data from comparative clinical trial:

• 24 subjects (22 completed), 2-week cross-over study
• Investigators masked to care system and subjects masked to sponsor
• Subjects used each of three different MPS for 2 weeks
• 1-week wash-out period between each cross-over (daily Disposables)
• Rub and rinse with PX1 and PX2, rinse only with PQ
• High water content Group 2 lenses discarded at each cross-over
• Variables assessed: graded and digitally analysed corneal staining and other variables (subjective comfort (0-10), symptoms, bulbar, limbal, palpebral redness, palpebral roughness, preference)

Results:
Corneal Staining

• Significantly less staining with PQ than PX2
• Investigator grading similar result
• Peripheral Presentation
• 3 or more regions
• Strong correlation between total stained area and investigator grade

Comfort and Symptoms

• No significant differences in comfort
• No significant differences in symptoms reported
• Lens awareness and dryness were most frequently reported symptoms.

Corneal Staining and Comfort

• No correlation between comfort and staining

Hyperaemia and Palpebral Papillae

• No significant differences

Preference

• No significant difference in preference

Conclusion:

• Image analysis of corneal staining is a useful and repeatable especially for lower amounts of staining.
• Polyhexanide MPS can produce bilateral, punctuate staining involving three or more regions of cornea.
• Patient symptoms are unreliable in identifying solution related staining.
• The potential long-term effect of solution related staining are unknown.

Citation: