The time after starting lens wear when CO2 reaches a peak causing bleb formation?

The time after starting lens wear when CO2 reaches a peak causing bleb formation?

• A. 10 minutes
• B. 30 minutes
• C. 60 minutes
• D. 90 minutes

Answer: (B)

The main idea is how hypoxia from wearing a contact lens builds up CO2 in the front of the eye and leads to edema that can produce bleb-like elevations. As the lens sits on the eye, tear exchange is reduced and the barrier to gas diffusion slows CO2 would normally escape. CO2 accumulates in the tear film and corneal tissues, causing mild edema and the appearance of small bleb-like pockets under the lens. This buildup reaches its peak around about 30 minutes after lens wear begins, when the imbalance between CO2 production and removal is greatest. After this point, the system starts to stabilize as gas exchange reaches a new balance, so the maximum edema/bleb effect is most likely observed around half an hour of wear.

The main idea is how hypoxia from wearing a contact lens builds up CO2 in the front of the eye and leads to edema that can produce bleb-like elevations. As the lens sits on the eye, tear exchange is reduced and the barrier to gas diffusion slows CO2 would normally escape. CO2 accumulates in the tear film and corneal tissues, causing mild edema and the appearance of small bleb-like pockets under the lens. This buildup reaches its peak around about 30 minutes after lens wear begins, when the imbalance between CO2 production and removal is greatest. After this point, the system starts to stabilize as gas exchange reaches a new balance, so the maximum edema/bleb effect is most likely observed around half an hour of wear.