MSD Lens

Problem Solving


Excessive Apical

Sag Value
Too High
Insertion bubbles are common. To avoid, completely fill the bowl of
the lens with solution prior
to applying.
If excessive central touch and bubbles for in the scleral area, the lens is not properly aligned with the sclera but instead is rocking on the cornea. The wearer may also complain of edge awareness in this situation. To correct, increase the sag depth value. If bubbles form in the central zone of the lens, this means the sag depth value is too high. To correct this, reduce the sag depth value.
Excessive Mid-peripheral Clearance
Small bubbles that move around are acceptable as long as they don’t cross over the pupil and interfere with vision.  However, bubbles that are fairly stationary are not acceptable and the fit should be modified to eliminate them. When the proper sag depth value has been determined but bubbles still persist in the mid-peripheral/limbal zone clearance, keep the sagittal depth value the same, but choose a decreased mid-peripheral/limbal zone clearance value. When conjunctival impingement occurs showing excessive blanching; order a lens with a flatter edge, either 1-Flat or 2-Flat. Depending on the lens diameter, increase the profile, increase the sag, or depending on the severity, consider all three options simultaneously.


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