The negative intrathoracic pressure may cause the left atrium to expand and stretch its walls during each OSA event. Over time, the repetitive stretching of the left atrium  may result in a persistent left atrial enlargement. Diagnosis

LAE is suggested by an  electrocardiogram (ECG)  that has a pronounced notch in the P wave. However, if atrial fibrillation is present, a P wave would not be present. In any case, LAE can  be diagnosed and measured using an echocardiogram (ECHO) by measuring the left atrial volume (LAVI). Characterizing the size of the left atrium according to its volume is preferred over a single linear dimension since enlargement can be different for different directions. For example, because of the smaller distance in the thoracic cavity between the sternum and spine, compared to the other directions, less  room exists for enlargement of the left atrium along the anteroposterior axis. By approximating the shape of the left atrium as an ellipsoid, its volume can be calculated from measurements of its dimensions along  three perpendicular directions.Indexing the left atrial volume to body surface area (volume/BSA) is recommended by the American Society of Echocardiography and the European Association of Echocardiography. The values for volume/BSA in the following table are the best validated, and are the same for both men and women. == References ==
Nummular keratitis is a feature of viral keratoconjunctivitis. It is a common feature of adenoviral keratoconjunctivitis (an ocular adenovirus infection), as well as approximately 1/3rd of cases of Herpes Zoster Ophthalmicus infections. It represents the presence of anterior stromal infiltrates. Unilateral or bilateral subepithelial lesions of the cornea may be present. Slit lamp examination reveals multiple tiny granular deposits surrounded by a halo of stromal haze. After healing, residual nummular scars often remain. Disciform keratitis occurs in 50% of individuals with Nummular keratitis, but Nummular keratitis always precedes Disciform keratitis. Treatment
Lubricating eye drops
Topical dilute steroid drops in tapering doses (debatable, see: Adenoviral keratoconjunctivitis)


== References ==