Welcome to question of the day #246

Welcome to question of the day #246

I know how to set up a trial frame and I also know that if I don’t set it up properly I may end up recommending a suboptimum prescription. Do you have any hints and tips on trial frame setup?

I have provided a procedure for trial frame setup below so you can check your setup procedure against mine. I thought I get straight into my hints and tips.

Make sure the sidearm is slightly angled down so that there is a pantoscopic tilt of around 10 degrees. This mimics the recommended pantoscopic tilt for spectacle frames.

Adjust the sidearm to fit snuggly behind the ear making sure the patient is as comfortable as can be expected while wearing a trial frame.

Ensure the frame is straight on the nose.

Check the pupillary distance of the trial frame matches the pupillary distance of the patient.

Ensure the nose rest is on the nose.

Check that the patient is looking through the centre of the lens(s).

Here is the general setup procedure.

Right and left monocular pupillary distances can be adjusted by rotating the adjusting knob of each eye, located above each lens well. The arrows above the lens wells indicate each monocular pupillary distance. Adding the PD values for each eye equals the binocular PD value.

The temple length can be adjusted by loosening the knob on top of the temple and pulling on the end of the temple. When the correct temple length has been established, the knob may be tightened to secure the length.

There are two knobs that control the position of the nose pad. The knob at the top of the frame controls the height of the nose pad. The angle of the frame in relation to the patient’s face is controlled by the knob on the front of the frame. When adjusting the nose pad, remember that the standard distance from the lens to the cornea is 12mm.

Centre the patient’s eyes with the optical centres of the lenses.

For optimal optical clarity, insert the least number of lenses possible to create the desired power.

The highest-powered lens should be placed closest to the cornea (in the back lens clamp/cell).

Always replace the trial lenses in the case when not in use.

Insert the lens quickly and accurately.