This ppt is about wettability test done in contact lens

1. Wettability
Presented By Shagufta Kadri & Yogita
Soni
By 3rd Year(B.Optom)
From Aditya Jyot Institute of Optometry

2. Wettability
In Vitro: Wetting angle
Sessile Drop
Wilhelmy plate
Captive bubble
In Vivo:
Tear coverage
Break up time
Drying time

3. Sessile Drop (water in Air)
Zero angle = completely wettable
Low angle = somewhat wettable
Large angle(especially >90degree) = poorly
wettable

4. Sessile Drop (water in Air)
• More Wettable Less Wettable
• 0= >90degree
• 0= <90degree Drop of Water
• 0= contact angle
Material A Material B Material C

5. Advancing & Receding Angle
• 0 Advancing angle > Receding angle
• 0 advancing 0 receding
• 0
• 0
Material A Material A

6. Wilhelmy Plate
• Material A Material A
• Advancing Receding
•
• Water
• 0 advancing > 0 receding

7. Captive Bubble
Tangent to bubble point of contact Controlled air supply
Lens being tested
Air Bubble
Tangent to surface Water

8. In Vivo Test
Tear Coverage:
Assessment of the ability of tears to form a
complete film over the lens surface

10. Break up time
• An assessment of ability of a lens to retain a
complete tear film
• Aqueous layer evapourates
• Lipid layer diffuses into aqueous
• Cessation of blinking to first appearance of break in
the tear film
• Short time indicates poor wettability

11. Thank You