Sleep apnea linked to hard-to-diagnose eye disorders

A British study finds that the condition known as floppy eyelid syndrome (FES) is strongly associated with obstructive sleep apnea (OSA), implying that when doctors see FES in a patient, they should also look for OSA, and vice-versa. The study, published in April's Ophthalmology, the journal of the American Academy of Ophthalmology, describes factors shared by OSA and FES and specific findings on how FES develops that will help doctors better diagnose and treat patients.

People with OSA face several health challenges–at worst, they are at risk of dying of oxygen deprivation when breathing slows or stops during sleep. OSA can contribute to or be aggravated by high blood pressure, diabetes, obesity and other systemic problems. Researchers led by Daniel G. Ezra, MD, MRCOphth, of Moorfields Eye Hospital, London, England, found the strong OSA-FES association in a case-controlled study of 102 patients tracked between 1995 and 2008; 102 matched controls were also tracked.

"About one-third (32 of 102) FES patients in our study also had OSA," Dr. Ezra said. "The significant association of the two disorders was evident even when we considered and controlled for patients' body-mass index (BMI, an indicator of whether obesity was a factor). FES is often considered a disease of overweight, middle-aged men, but our study did not find a patient cluster based on age, gender or BMI," he added.

People with FES have rubbery-textured upper eyelids that may easily flip up during sleep, exposing the "whites of the eyes," which can lead to dry, irritated eyes and/or discharge. The Moorfields research and other studies suggest that central nervous system arousal may be impaired in OAS suffers, so they do not wake up as people normally do when breathing slows or stops, or when the eyelid is subjected to extreme stress. People with OSA often preferentially sleep on one side, which could result in intense, repeated pressure on the eyelid on that side of the face. A combination of these factors may contribute to or cause FES. The Moorfield report notes that FES resolved in an OSA patient who was treated with a continuous positive airway pressure mask.

Also, the Moorfields study confirms earlier findings that FES is associated with keratoconus, in which the cornea thins out and becomes cone-shaped. Patients with FES often rub their eyes excessively, perhaps contributing to keratoconus. Eye M.D.s (ophthalmologists) should recognize that visual problems in patients with FES may be due to keratoconus– rather than dry eye disease or other surface irritation–and treat them accordingly, the researchers say.

In a separate study, Dr. Ezra and colleagues followed 78 FES patients who had had been treated surgically for FES at Moorfields Eye Hospital within a 13 year period that began in 1995. Of the surgical methods used, better outcomes resulted for the procedures known as medial and lateral canthal placation, and upper lid lateral tarsal strip. But outcomes for all procedures were less favorable than reported in earlier studies; the Moorfields study attributes this difference to their study's longer follow-up period.