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Nocturnal lagophthalmos frequently is missed by ophthalmologists. A three-level classification may help ophthalmologists spot the disorder in patients whose condition might otherwise be overlooked.
New York-Nocturnal lagophthalmos frequently is missed by ophthalmologists, according to Robert Latkany, MD, a dry eye specialist. He has devised a three-level classification to help ophthalmologists spot the disorder in patients whose condition might otherwise be overlooked.
"There are numerous patients with this condition in whom the diagnosis is being missed,"he said. "Examination for lagophthalmos is rarely part of the typical eye examination, but it should be. It is a very common presentation in my practice."
The first step, he said, is asking patients how they feel upon awakening. "Most of the time, a diagnosis of lagophthalmos can be made by means of a good history," Dr. Latkany said. "If patients are asked to describe how they feel upon awakening and they respond 'Great,' chances are that they do not have lagophthalmos or they don't have dry eye with lagophthalmos. Having lagophthalmos alone does not make a patient symptomatic. Sleeping with the eyes open by about 1 mm does not always translate into horrendous ocular surface pain, burning, or a foreign body sensation."
Conversely, he said, when patients are asked the same question and they respond with statements such as "I am a light sleeper," "I wake up several times during the night," "I put drops in my eyes several times a night," "I wake up with tremendous burning," or they describe blurriness, sharp pain, redness, or irritation upon awakening, they likely have nocturnal lagophthalmos with mild dry eye. These patients achieve a measure of ocular comfort when they take a shower as a result of the humidity, he explained.
In patients in whom the history is not helpful, he suggested examining the patients using fluorescein dye for the presence of a line of erosions across the cornea. "Patients who have moderate to severe dry eye with lagophthalmos have punctate erosions across the bottom one-fifth of the corneal surface resulting from the chronic nocturnal exposure to air," he said. If erosions are apparent elsewhere on the cornea, then lagophthalmos is likely not the sole cause of the erosions, he added.
Other clues to a possible diagnosis of lagophthalmos are a patient with wide interpalpebral fissure between the upper and lower eyelids or scleral show at the 6 o'clock position. "Individuals with scleral show often have lagophthalmos," Dr. Latkany said.
A physical examination of the eyelid position should lead to a diagnosis based on the following classification that was reported in The Ocular Surface (2006; 4:44-53).
Type 1 is obvious lagophthalmos. This is evident by asking the patient to close his or her eyes as if sleeping. The gap between the lids is readily apparent. "This type typically is thought to be the only type of lagophthalmos," Dr. Latkany said. incidence studies done in the 1950s and 1960s had medical students as subjects and reported rates of obvious lagophthalmos ranging from about 3% to 4%." Since that time, he added, no studies have been published on lagophthalmos, with the exception of one in patients with leprosy.
Type 2 is eyelash-obscured lagophthalmos that is visible on slit-lamp examination. When patients are examined at the slit lamp for lagophthalmos, thick eyelashes can obscure the view of the clinician, and it appears as though the eyes are closed, Dr. Latkany emphasized.