@article{3030341,
    title = "Effects of Continuous Positive Airway Pressure Treatment for Obstructive
Sleep Apnea-Hypopnea Syndrome on Corneal Morphological Characteristics",
    author = "Chalkiadaki, Evangelia and Andreanos, Konstantinos and Karmiris, and Efthymios and Mani, Aikaterini and Kastanakis, Emmanouil and and Amfilochiou, Anastasia and Papaconstantinou, Dimitrios and Koutsandrea, and Chrysanthi and Georgalas, Ilias",
    journal = "Cornea : The Journal of Cornea and External Disease",
    year = "2021",
    volume = "40",
    number = "8",
    pages = "988-994",
    publisher = "Lippincott, Williams & Wilkins",
    issn = "0277-3740, 1536-4798",
    doi = "10.1097/ICO.0000000000002581",
    keywords = "obstructive sleep apnea-hypopnea syndrome; corneal endothelium;
continuous positive airway pressure; REM sleep",
    abstract = "Purpose: To evaluate the effects of continuous positive airway pressure
(CPAP) therapy on corneal endothelial morphometry and pachymetry in
patients with obstructive sleep apnea-hypopnea syndrome (OSAHS).
Methods: This prospective, observational study included patients with
OSAHS who were evaluated right before and after the commencement of CPAP
treatment. Each patient underwent a detailed ophthalmologic examination
and assessment of their corneal endothelium with a noncontact specular
microscope (Tomey EM-3000; Tomey Corp). Endothelial cell density,
coefficient of variation of cell area (CV), hexagonal cell appearance
ratio (%Hex), and central corneal thickness were measured. The
post-CPAP results were compared with the results of a control group. The
differences in the corneal parameters between pre- and post-CPAP therapy
of the OSAHS group were correlated with the pretreatment polysomnography
results. Results: Twenty-seven distinct eyes of 27 patients recently
diagnosed with OSAHS and 30 eyes of 30 healthy individuals were used for
the statistical analysis. The mean age of patients with OSAHS was 54.2
+/- 11.8 years, and after 9.6 months (range 3-18 mo) of good adherence
to CPAP treatment, their CV values, indicating polymegathism, decreased
from 41.7 +/- 8.7 to 38.3 +/- 5.8 (P = 0.04), whereas %Hex, indicating
pleomorphism, increased from 45.8% +/- 8.2% to 48.4% +/- 6.6% (P =
0.008). Their post-CPAP corneal parameters did not differ significantly
from those of the control group (P > 0.05). A significant positive
correlation was observed between the decrease in CV and the duration of
the treatment (Rs = 0.566, P = 0.002), as well as the pre-CPAP nonrapid
eye movement (NREM) sleep percentage (Rs = 0.459, P = 0.02). A negative
correlation was noted between the decrease in CV and the percentage of
rapid eye movement (REM) sleep (Rs = -0.459, P = 0.02). Conclusions:
Better oxygenation during sleep, resulting from increased CPAP
adherence, had a significant influence on corneal endothelium, providing
an improvement in corneal polymegathism and pleomorphism, with a
potential return of CV and %Hex to their normal values. Greater
improvement in polymegathism was observed in patients with greater
proportion of NREM sleep."
}