Haw's syndrome is a common finding in cats and is defined as an idiopathic (unknown cause) bilateral elevation of the third eyelids. All other aspects of the ophthalmic examination normal. This problem normally resolves in 3-4 weeks without treatment, or may reflect malaise due to other undiagnosed problems such as:
- cat flu
- Dysautonomia (Key-Gaskell syndrome): clinical signs include bilateral elevated third eyelids, dilated nonresponsive pupils, keratoconjunctivitis sicca, dry mucosal surfaces, anorexia, lethargy, regurgitation, megaesophagus, bradycardia, megacolon, distended bladder (see Dysautonomia)
- Tranquilization: many tranquilizers (e.g., acepromazine) cause bilateral elevation of the third eyelid. Fatigue can cause transient third eyelid elevation, especially in cats prone to ectropion.