Candidates should direct their examination towards determining the:
This is relevant for determining severity of keratopathy as well as the viability of certain surgical repair options (such as prolonged surgical closure of the lids).
Stand back from the patient and observe for a few seconds, then advance closer and continue to observe. While observing comment on the features mentioned below:
Pull the lower lid down and ask the patient to look up. Observe the inferior fornix. Then ask the patient to look down. Observe the tarsal plate and fornix for movement.
Distraction and “Snap back” test: Pull the lower lid directly away from the globe and observe how far it can be distracted (> 8 - 9mm is considered “abnormal”) and how quickly it “snaps back” onto the globe when released. A normal eyelid does not require a blink to reposition itself on the globe
Note any rounding of the lateral canthus. Pinch the lower eyelid and pull medially (“Medial distraction test”). Medial distraction of the lateral canthus > 2mm is abnormal. Compare with the contralateral side
Note the resting position of the punctum. Pinch the lower eyelid and pull laterally (“Lateral distraction test”)
There is no universally agreed grading system for MCT laxity. Readers are encouraged to refer to Olver et. al. Lower Eyelid Medial Canthal Tendon Laxity Grading. Ophthalmology. 2001 Dec;108(12):2321-5.
This completes the examination that has been done up to this point. Look for:
The pathogenesis of entropion is very similar to that of ectropion- i.e. horizontal lid laxity and inferior retractor instability (± cicatricial components). Various theories have been proposed but it is not known exactly why some people develop ectropion and others entropion as differing sequelae to similar involutional processes.
Most cases of entropion will require definitive surgical treatment. Cases of entropion which are constant (not intermittent) and not controlled by conservative measures should be repaired as promptly as possible due to the risk of corneal infection or scarring from lashes rubbing on the cornea.
Localised pharmacological paralysis of the pre-tarsal orbicularis can prevent the overriding and temporarily resolve the entropion. The effect is variable in duration and efficacy and will not work in a purely cicatricial ectropion. Administer 5 units of Botox® (Allergan, Dublin, Ireland) (or equivalent dose of other botulinum toxin) in 0.1mL to the medial and lateral pre-tarsal orbicularis muscle as an initial dose (see Figure 5.2.3 below).
Numerous surgical procedures have been described for entropion repair. The choice depends on which entropion components are present and surgeon preference. For examination purposes, it is appropriate to become familiar with one or two procedures in detail as these will correct most problems, while maintaining awareness of the limitations of the chosen approach.
Standard approaches for entropion repair include the following, either individually or in combination:
These have a high rate of recurrence but their effect can last months to years in some patients and can be placed in the clinic with minimal risk of haemorrhage.
A lateral tarsal strip leads to long-term resolution of the entropion in the majority of cases, particularly when combined with everting sutures.
A skin / anterior approach is preferable to avoid conjunctival scarring which could contribute to the recurrence of the entropion.
The lid is split into anterior and posterior lamellar, and the anterior lamella is recessed relative to the posterior lamella. This procedure is typically used for cicatricial entropion where conjunctival surgery would cause inflammation and exacerbate the primary pathological process (most commonly mucous membrane pemphigoid).
This is necessary for repair of cicatricial entropion where the posterior lamella is shortened. Donor sites include hard palate (useful as it also has mucous membrane attached), sclera or ear cartilage. Commercial allograft materials are also available
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Vitreoretinal Surgery Online
This open-source textbook provides step-by-step instructions for the full spectrum of vitreoretinal surgical procedures. An international collaboration from over 90 authors worldwide, this text is rich in high quality videos and illustrations.