What is the average horizontal visible iris diameter (HVID) for a patient?

The average horizontal visible iris diameter (HVID) for a patient is typically around 11.5 mm. This measurement is essential in contact lens fitting, as it provides critical information regarding the size of the lens required for optimal comfort and vision. An accurate HVID is crucial for ensuring that the contact lens covers the iris adequately, preventing lens movement and ensuring stable vision.

Understanding the significance of HVID helps practitioners choose the correct contact lens size, considering factors like corneal diameter and eye shape. While HVID can vary slightly among individuals, the average of 11.5 mm is a widely accepted standard in the field, making it a vital piece of information in fitting procedures.

Other options reflect variations that might be observed, but 11.5 mm is the most recognized average and serves as a reliable benchmark for practitioners working in vision care.