Dry Eye Dx and Tx
How Treatment for Sleep Apnea Can Lead to Dry Eye
BY KATHERINE M. MASTROTA, MS, OD, FAAO
Obstructive sleep apnea (OSA) is a chronic disorder characterized by starts and stops of breathing during a night of sleep. Documented prevalence of OSA in a worldwide general population ranges from 3% to 7% in adult men and from 2% to 5% in adult women (Punjabi, 2008). It is estimated that 22 million Americans suffer from sleep apnea, with 80% of the cases of moderate and severe OSA undiagnosed (www.sleepapnea.org).
The global sleep apnea devices market is expected to reach $5.3 billion by 2020 from an estimated $3.7 billion in 2015; by location, North America is expected to command the largest share of this market due to increased awareness of sleep apnea in the region (www.marketsandmarkets.com/Market-Reports/sleep-apnea-devices-market-719.html).
What Causes OSA?
OSA is a decreased airflow due to repetitive complete or partial obstruction of the upper airway associated with progressive respiratory effort to overcome the obstruction. These obstructive respiratory events are typically associated with cortical microarousals and oxygen desaturation, leading to sleep fragmentation (Caples et al, 2005). Clinical symptoms suggestive of OSA include loud snoring, choking or gasping during sleep, morning headaches, insomnia, and daytime sleepiness (Lee et al, 2008). Several risk factors have been identified in the development of OSA, but the strongest risk factor is obesity, reflected by such markers as body mass index, neck circumference, and waist-to-hip ratio (Tishler et al, 2003). Other risk factors include aging (up to age 65), male gender, menopause, craniofacial abnormalities, upper airway anatomy, smoking, alcohol, and genetic predisposition (Young et al, 2004).
Effects of OSA Treatment
Continuous positive airway pressure (CPAP) therapy is the mainstay of OSA treatment. The principle of CPAP in OSA is to provide air under positive pressure through an interface (nasal or face mask), thus creating a pneumatic splint in the upper airway that prevents collapse of the pharyngeal airway, acting at all potential levels of obstruction (Sullivan et al, 1981).
Some documented adverse effects of CPAP therapy include nasal congestion, rhinorrhea, nasal dryness, sinus pain, mask discomfort, skin abrasions, and air leakage (Sharma et al, 2015). Anterior segment complications secondary to CPAP units include vascularized limbal keratitis, recurring corneal ulcers, bacterial conjunctivitis, and, commonly, ocular dryness (Harrison et al, 2007).
Patients may experience dry eye due to air leakage from the mask into their eyes, which is especially troublesome for patients who have pre-existing dry eye. Excessive ocular drying from CPAP masks can be avoided if users are familiar with the availability of eye protection, typically in the form of eye shields. Eye shields should be compatible with a patient’s CPAP mask design and be properly fit. Eye protection masks specifically designed for use with CPAP devices are available that can also protect sensitive areas of the face from being chafed by the CPAP mask (contact author for information).
Finally, specialty dental devices are a viable alternative to treating sleep apnea for patients who cannot tolerate mask CPAP therapy.
Remember to inquire about CPAP use in your dry eye patients, and be prepared to provide ocular occlusion options. CLS
For references, please visit www.clspectrum.com/references and click on document #241.
Dr. Mastrota is Program Chair-Elect of the Anterior Segment Section of the American Academy of Optometry. She is a consultant or advisor to Allergan, B+L, BioTissue, NovaBay Pharmaceuticals, and OcuSoft and is a stock shareholder of TearLab Corporation. Contact her at firstname.lastname@example.org.