Involutional entropion occurs in the lower eyelids (Fig 12-4). Causative factors include horizontal laxity of the eyelid, attenuation or disinsertion of eyelid retractors, and overriding by the preseptal orbicularis oculi muscle. Horizontal laxity can be assessed with snapback and distraction testing. Such laxity is a result of senescence, with stretching of the eyelid and canthal tendons. Typically, the lower eyelid retractors maintain the eyelid margin in proper orientation. However, attenuation of the eyelid retractors (capsulopalpebral fascia and inferior tarsal muscle), in conjunction with preseptal orbicularis override, allows the inferior border of the tarsus to roll forward and superiorly, resulting in inward rotation of the margin. Several clinical clues may suggest disinsertion of the retractors:
a white subconjunctival line several millimeters below the inferior tarsal border caused by the leading edge of the detached retractors
a deeper-than-normal inferior fornix
elevation of the lower eyelid
minimal movement of the lower eyelid on downgaze
Figure 12-4 Involutional entropion of the right lower eyelid.
(Courtesy of Bobby S. Korn, MD, PhD.)
After the entropic eyelid has been placed in its normal position, the clinician can detect superior override of the preseptal orbicularis by instructing the patient to forcefully close the eyelids. This maneuver accentuates the inward rotation of the lower eyelid margin. Procedures to repair involutional entropion of the lower eyelid fall into 3 groups: temporizing measures, horizontal tightening procedures, and retractor repair. Often, a combination of procedures is necessary. If trichiasis is present, it may require specific treatment, either in conjunction with the entropion repair or subsequently, if the eyelashes remain misdirected after proper positioning of the eyelid margin (see the Trichiasis section).
Lubrication and a bandage contact lens may be used to protect the cornea from mechanical abrasion by the misdirected eyelashes. Rotational suture techniques (Fig 12-5) are occasionally helpful as temporizing measures in involutional entropion; however, when these techniques are used in isolation, recurrence is anticipated.
Figure 12-5 Rotational suture repair of spastic entropion.
(Illustration by Mark Miller.)
Direct repair of lower eyelid retractor defects through a skin incision (Fig 12-6A) or a transconjunctival approach (Fig 12-6B) can be performed to stabilize the inferior border of the tarsus. In addition, a small amount of preseptal orbicularis oculi muscle can be removed in selected patients who have preseptal orbicularis overriding the pretarsal orbicularis. Reinsertion of the eyelid retractors and limited myectomy of the orbicularis in conjunction with a lower eyelid shortening procedure such as a lateral tarsal strip operation or wedge resection (see Fig 12-2B) correct all 3 etiologic factors in involutional entropion (Video 12-2).
Transconjunctival lower eyelid entropion repair. Courtesy of Bobby S. Korn, MD, PhD.
Figure 12-6 Retractor repair of lower eyelid involutional entropion. A, Transcutaneous approach. B, Transconjunctival approach.
(Illustration by Mark Miller.)
Excerpted from BCSC 2020-2021 series: Section 10 - Glaucoma. For more information and to purchase the entire series, please visit https://www.aao.org/bcsc.