Sleep Apnea in Keratoconus Patients: Who's Most at Risk?

Christopher J. Rapuano, MD


July 31, 2012

Prevalence of Sleep Apnea Syndrome and High-Risk Characteristics Among Keratoconus Patients

Saidel MA, Paik JY, Garcia C, Russo P, Cao D, Bouchard C
Cornea. 2012;31:600-603

Study Summary

In this study, Saidel and colleagues identified 216 patients with unequivocal clinical and topographical keratoconus. An attempt was made to contact every patient for a telephone survey using the Berlin Questionnaire, a standard, well-accepted sleep apnea screening tool shown to effectively classify patients into low- and high-risk categories by calculating body mass index (BMI) and asking various questions. The survey was completed by 92 patients with keratoconus; 92 consecutive new patients to the contact lens service were recruited as controls. The control participants all had good vision and normal results on slit lamp examinations and normal corneal topography and power.

Compared with controls, the patients with keratoconus were more likely to be male, have a higher BMI, and have a family history of keratoconus. One fifth (19.6%) of the keratoconus group had a history of sleep apnea, whereas only 6.5% of control patients had such a history (P = .009). More than half (53.3%) of patients with keratoconus and 27.2% of controls were found to be at high risk for sleep apnea (P < .001) according to Berlin Questionnaire criteria. Increased BMI was found to be a statistically significant risk factor for sleep apnea in the keratoconus patients. Older age, higher BMI, and a family history of sleep apnea were statistically significant risk factors for sleep apnea in the control patients.


The sleep apnea syndrome is a sleep disorder defined by repetitive episodes of apnea lasting for at least 10 seconds during sleep, associated with reduced oxygen saturation. The continuum of sleep-related breathing disorders includes snoring at the milder end of the spectrum, the upper airway resistance syndrome in the middle (characterized by sleepiness during waking hours, and snoring but no hypoxia), and obstructive sleep apnea (OSA) at the more severe end. OSA is associated with sleepiness during waking hours, snoring, spousal reports of apnea during sleep, and hypoxia.

OSA has been linked to heart disease (myocardial infarction, heart failure, and arrhythmia), hypertension, stroke, diabetes, and sleepiness-related automobile and other accidents. Untreated sleep apnea has been associated with increased risk for premature death. An association between sleep apnea and keratoconus has long been suspected.

Sleep apnea is associated with obesity, which has also been linked with keratoconus in some studies. This study showed a statistically significantly higher BMI in keratoconus patients than in controls. In my experience, many keratoconus patients are not obese but a high percentage of patients with severe keratoconus are overweight or obese.

The floppy eyelid syndrome has been linked with both obstructive sleep apnea and keratoconus in several studies. I currently evert the eyelids of all my patients with keratoconus to look for this syndrome. Floppy eyelids can interfere with good, comfortable contact lens wear, which is difficult enough to achieve in patients with keratoconus without the added problem of floppy eyelids. Even in patients who do not wear contact lenses, this disorder can cause severe chronic redness, irritation, and discharge. If I diagnose significant floppy eyelids, I refer patients to an oculoplastic specialist for evaluation and potential surgical repair. Irritative symptoms and contact lens intolerance can be reduced dramatically with appropriate treatment, which often involves surgery.

Although I have asked my obese patients (especially keratoconus patients) about sleep apnea symptoms for years, I am now beginning to query all my patients with keratoconus. Just as important is asking family members about the patient's sleep habits, chiefly snoring and sleepiness during the day. Not infrequently, the patient will deny such symptoms while the family member proceeds to rattle off multiple symptoms displayed by the patient.

I advise patients with sleep apnea symptoms to see their internist or family care provider (who receives a letter from me) and consider formal overnight sleep testing. Although I leave the workup and treatment of sleep apnea to the patients' other physicians, I tell them that if they have sleep apnea continuous positive airway pressure can help significantly. I also mention that weight loss and avoiding alcohol for 4-6 hours before sleep are often beneficial and that sleeping on one's side as opposed to the back or stomach may be of some value. I make it clear that treating the sleep apnea may improve their general health and reduce their risk for multiple medical problems, including premature death, but unfortunately isn't expected to make their keratoconus any better.



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