Prolapsed Orbicularis Muscle
(Lower Eyelid Flaccidity)

Another important muscle in the facial structure is the orbicularis.  This muscle responds to blinking, squeezing and closure of the eyelids over the ocular prosthesis, but when it has been weakened or traumatized the lower eyelid can prolapse (fall down or forward).  This occurrence is more common with geriatric patients when the muscle tone becomes too flaccid.  This breakdown of the lower external lid structure is then compounded by eversion of the orbital fatty tissue and a reduction in depth or loss of the lower cul-de-sac.  At this juncture there is no longer a supportive coexistence between the eyelids, and the prosthesis can become easily displaced or extrude.

This case presents such a (geriatric) patient where the orbicularis muscle became so flaccid that the lower eyelid had begun to prolapse, this then becomes the precursor for a shallower lower fornix.  To restore definition to the lower fornix it was necessary to apply constant external pressure with a stemmed conformer for a week.  A new modified prosthesis was then designed to extend deeper into the canthi (corners of the eye), which elevated the weakened lower eyelid and relieved any weighty pressure within the fornix.

Figure 21A Whenever there is absence of a prosthesis in age related cases (geriatrics), the following conditions become apparent.  There is marked anophthalmic enophthalmos (lack of orbital volume) that causes the upper eyelid to collapse, resulting in a pseudoptosis.  The adipose tissue (between the eyebrow and upper eyelid margin) if not lost during the enucleation procedure can migrate down and forward into the lower cul-de-sac thereby decreasing the depth of the fornix.  This age related flaccidity of the orbicularis muscle is demonstrated here where the lower eyelid and lashes begin to prolapse (fall forward).

Figure 21B Once a prosthesis is placed within the orbit (with proper volume, size and shape the adnexa is restored to near symmetrical balance with the sighted eye.