This form of dry eye can occur despite adequate tear production, or it can coexist with other forms of dry eye.
It may be unilateral or bilateral.
Types:
(1) epitheliopathies that interfere with tear film production and/or retention
(2) lid and/or globe pathology that interferes with spreading of the tear film over the globe
(3) environment-related hyperevaporative states, typically involving some combination of very low humidity, hot weather, and/or rapid air movement (wind, fan, etc)
Epitheliopathies include:
(1) abnormalities of the corneal epithelium (dystrophy, etc)
(2) diabetic keratitis
(3) keratitis associated with hypoparathyroidism
(4) epithelial dystrophy
(5) limbal deficiency
Lid-globe pathologies that can prevent an even distribution of a tear film include:
(1) lid coloboma
(2) ectropion
(3) lagophthalmos
(4) lid palsy
(5) exophthalmos
(6) floppy lid
(7) benign cysts
(9) pterygion
(10) fissure in the eyelid
