Fogging the patient during astigmatic testing is recommended.

• A. True
• B. False
• C. Only for high astigmatism
• D. Not needed if patient is cooperative

Answer: (A)

Fogging helps keep accommodation in check so your responses reflect the eye’s true optical error rather than the patient’s effort to focus. By introducing a little plus power, you relax the accommodative system, preventing the patient from actively accommodating to make one meridian appear clearer. This creates a more stable baseline for determining the cylinder power and axis. After establishing a fogged, relaxed state, you can gradually reduce the plus to refine the astigmatic correction without accommodation skewing the results. This is a standard step in astigmatic testing because it improves reliability regardless of how cooperative the patient is or how pronounced the astigmatism may be.