Corneal Topographic Changes in Different Grades of OSA

Obstructive sleep apnea (OSA) syndrome is a disease characterized by recurrent total or partial upper airway collapse during sleep, interrupting or reducing the airflow, and after ward resulting in temporary awakening which causes restoration of flow of the upper airway. These intermittent complete (apnea) or partial (hypopnea) respiratory cessations decrease blood oxygen levels (hypoxia).

Upper airway stenosis causes hypoxemia and hypercapnia, which can lead to multiple organ dysfunction and is associated with systemic diseases, such as hypertension, diabetes, and coronary arteriosclerosis, and changes in the eyes include floppy eyelid syndrome, keratoconus, and glaucoma.

The prevalence of OSA is between 2% and 10% in females and 4-20% in males and obesity is a major risk factor for the development of OSA.

With all the adverse effects associated with OSA, its secondary effects cause several ocular complications. Previous studies have shown that OSA is associated with increased risks of several vision-threatening and nonthreatening ocular disorders, including senile cataracts, normal-tension glaucoma, retinal ischemia, conjunctival hyperemia, and dry eye.

Several contributory mechanisms to the ocular complications of OSA have been reported, including intermittent hypoxia, oxidative stress, systemic inflammatory responses (such as interleukin-6 (IL-6), IL-8, tumor necrosis factor-alpha (TNF-α), C-Reactive protein (CRP), matrix metalloproteinase 9 (MMP-9), vascular cell adhesion molecule (VCAM), intercellular adhesion molecule (ICAM), selectins), sympathetic system overaction, damage effects of endothelin-1, and disruption of the blood-retinal barrier (BRB) (6-8). There are limited publications that manipulate the corneal topographic parameters in different degrees of OSA, especially in the Egyptian population.