Pharmacologic reversal of Horner's syndrome-related ptosis with apraclonidine.

A 20-year-old woman presented to the facial plastic and reconstructive surgery clinic for evaluation of left-sided ptosis. Her condition developed after she had undergone resection of a left cervical sympathetic chain schwannoma 1 year earlier. She said that she had to strain to see through her left eye, especially while reading. She also noted that she no longer perspired along the left side of her face, but she denied a history of dry eyes. On examination, she exhibited 3 mm of ptosis in addition to anisocoria (figure, A). Her visual acuity and extraocular movements were normal.

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The constellation of ptosis, miosis, and anhidrosis in our patient suggested the diagnosis of Horner's syndrome. The diagnosis of Homer's syndrome-related ptosis was confirmed by topical application into each eye of 1 drop of 0.5 % apraclonidine, which is a selective [[alpha].sub.2] receptor agonist with weak [[alpha].sub.1] activity. (1) Ten minutes after instillation, the ptosis resolved completely (figure, B). Although there have been some reports that apraclonidine can reverse anisocoria, (2) no significant change occurred in our patient.

The ophthalmic manifestations of Homer's syndrome are caused by a loss of input to the sympathetically controlled Muller's muscle and iris dilator muscle. Ptosis occurs as a result of a dysfunction of one or both of the upper eyelid elevators--the levator palpebrae superioris and Muller's muscle.

Garibaldi et al proposed that the resolution of ptosis by apraclonidine occurs as a result of denervation hypersensitivity of the [[alpha].sub.2] receptors in Muller's muscle. (1) The lack of response of the iris dilator muscle may be attributable to the fact that it is largely [[alpha].sub.1] receptor-dependent. In addition to apraclonidine, other sympathomimetic agents such as phenylephrine (2.5 and 10%) have been used. (3)

Long-term correction of ptosis requires surgical manipulation of the levator palpebrae superioris muscle and/or Muller's muscle. Common procedures include external levator muscle resection or advancement and Muller's muscle-conjuctival resection.

In addition to a thorough ophthalmic examination, the evaluation of ptosis should include some important eyelid measurements, including (4,5):

* the height of the palpebral aperture (normal: ~9 Mm);

* the distance from the upper eyelid margin to corneal light reflex in primary gaze (MRD1) (normal: 4 to 5 mm);

* levator function as determined by the amount of excursion of the upper eyelid with the brow fixed (normal: 12 to 17 mm); and

* the distance of the upper eyelid margin to upper eyelid crease (normal: 8 to 10 mm).

References

(1.) Garibaldi DC, Hindman HB, Grant MP, et al. Effect of 0.5% apraclonidine on ptosis in Homer syndrome. Ophthal Plast Reconstr Surg 2006;22(1):53-5.

(2.) Morales J, Brown SM, Abdul-Rahim AS, Crosson CE. Ocular effects of apraclonidine in Homer syndrome. Arch Ophthalmol 2000;118(7):951-4.

(3.) Glatt HJ, Fett DR, Putterman AM. Comparison of 2.5% and 10% phenylephrine in the elevation of upper eyelids with ptosis. Ophthalmic Surg 1990;21(3):173-6.

(4.) Mulvihill A, O'Keefe M. Classification, assessment, and management of childhood ptosis. Ophthalmol Clin North Am 2001;14(3):447-55.

(5.) Kao CH, Moe KS. Retrograde weight implantation for correction of lagophthalmos. Laryngoscope 2004;114(9):1570-5.

Eugene A. Chu, MD; Patrick J. Byrne, MD

From the Department of Otolaryngology--Head and Neck Surgery, The John Hopkins Hospital, Baltimore.