Adjusting The Aperture (Lids)

In cases of a too-narrow or too-wide lid opening, the use of a cylinder lens, by itself or in combination with plus or minus power lenses, will change the apparent shape of the lid opening.

If the patient’s lid opening is too wide, start by holding a –3.00 cylinder over the patient’s artificial eye at axis 180, and then rotate the lens slightly in different directions. You will see the lid shape change and take on a more narrow look. Holding the lens at axis 90 will produce the opposite effect.

The use of a minus cylinder to narrow the lid opening can also cause the iris to look smaller. In such cases, adding plus sphere power will neutralize this effect.