In humans and dogs, how do sex risk profiles differ for dry eye disease?

• A. Humans: females more at risk; Dogs: males predisposed for MGD
• B. Humans: males at risk; Dogs: females predisposed for MGD
• C. Humans: females more at risk; Dogs: females predisposed for MGD
• D. Humans: males at risk; Dogs: males predisposed for MGD

Answer: (C)

Differences in dry eye disease risk between species come down to the dominant disease mechanisms and how sex hormones influence them. In people, dry eye is most often aqueous-deficient and autoimmune-linked (think Sjögren’s syndrome), and women are disproportionately affected, especially with hormonal influences and autoimmune predisposition as they age. In dogs, when the issue is evaporative dry eye driven by Meibomian gland dysfunction, females appear more prone, likely because sex hormones affect Meibomian gland function and the tear film lipid layer. So the statement that humans have a female-associated risk and dogs have a female predisposition for MGD fits with the idea that the underlying pathophysiology of dry eye differs by species and by disease type.