5 Key Takeaways

• 1

  The PD ruler measures more than pupillary distance; it provides insights into lid position, iris diameter, pupil size, and blink dynamics.

• 2

  Assessing horizontal visible iris diameter and lid-to-limbus positioning can influence multifocal lens centration.

• 3

  Larger than average iris sizes may require larger diameter GP lenses and consideration of edge lift effects.

• 4

  Pupil size under room lighting can help predict the effectiveness of center-near multifocal lenses.

• 5

  Using the PD ruler as a first diagnostic tool can enhance fitting accuracy and reduce remakes in contact lens practice.