lag of accommodation

The dioptric difference between the accommodative stimulus and the accommodative response, where the eye under-accommodates for a near target. A normal lag is between 0.50 to 0.75 D, while a lag >1.00 D is considered abnormal and may cause symptoms like eyestrain, headaches, and blurred vision at near.
Lag of accommodation can be measured objectively using dynamic retinoscopy techniques such as MEM or Nott retinoscopy. It may occur due to reduced accommodative ability or uncorrected hyperopia. Treatment options include prescribing plus lenses at near or vision therapy to improve accommodative function.