With a flat fitting lens, a plus/minus tear lens is created and we need to add plus/minus to compensate.

With a flat fitting lens, a plus/minus tear lens is created and we need to add plus/minus to compensate.

• A. Plus tear lens; add minus.
• B. No tear lens; no compensation.
• C. Minus tear lens; add plus.
• D. Plus tear lens; add plus.

Answer: (C)

The main idea is that the tear lens formed beneath a flat-fitting GP lens changes the eye’s overall refractive power, so you must adjust the lens power to compensate. When a lens fits flat, there’s more space between the cornea and the posterior lens surface, which creates a tear lens with minus power. This minus tear lens reduces the eye’s effective refractive power, pulling the correction toward hyperopia. To counteract this and bring the refractive outcome back to the target, you add plus power to the contact lens. That’s why the correct approach is minus tear lens and add plus. The other options either describe the tear lens inaccurately or suggest no tear lens or power change, which doesn’t fit how tear lens interacts with a GP lens fit.

The main idea is that the tear lens formed beneath a flat-fitting GP lens changes the eye’s overall refractive power, so you must adjust the lens power to compensate. When a lens fits flat, there’s more space between the cornea and the posterior lens surface, which creates a tear lens with minus power. This minus tear lens reduces the eye’s effective refractive power, pulling the correction toward hyperopia. To counteract this and bring the refractive outcome back to the target, you add plus power to the contact lens. That’s why the correct approach is minus tear lens and add plus. The other options either describe the tear lens inaccurately or suggest no tear lens or power change, which doesn’t fit how tear lens interacts with a GP lens fit.