During Bell retinoscopy, if an initial against motion is observed, what adjustment helps reveal accommodative lag?

During Bell retinoscopy, if an initial against motion is observed, what adjustment helps reveal accommodative lag?

• A. Remove minus lenses until neutral
• B. Move the target away until neutral
• C. Add -0.50 D to stimulate accommodation
• D. Add +0.50 D increments to relax accommodation and create a lag

Answer: (D)

The main idea is to use plus fogging to relax accommodation and reveal the lag under near viewing. When you see an initial against motion at near, the eye is currently accommodating more than the demand. By adding plus power, you reduce the accommodative effort required (you’re fogging the eye). If there is an accommodative lag, the reflex will begin to shift toward neutral or with motion as you relax accommodation. The amount of plus needed to bring the reflex to neutral or within with motion equals the lag amount. So adding plus in small steps (for example, +0.50 D increments) until you observe the reflex move out of against motion and toward neutral or with motion is the way to reveal and measure accommodative lag.

The main idea is to use plus fogging to relax accommodation and reveal the lag under near viewing. When you see an initial against motion at near, the eye is currently accommodating more than the demand. By adding plus power, you reduce the accommodative effort required (you’re fogging the eye). If there is an accommodative lag, the reflex will begin to shift toward neutral or with motion as you relax accommodation. The amount of plus needed to bring the reflex to neutral or within with motion equals the lag amount. So adding plus in small steps (for example, +0.50 D increments) until you observe the reflex move out of against motion and toward neutral or with motion is the way to reveal and measure accommodative lag.