Dry eye disease (DED) is a multifactorial disease in which the tear film’s homeostasis is lost, along with other ocular symptoms such as tear film instability and high osmolarity, neurosensory abnormalities, and ocular surface inflammation and damage. DED is a condition of lacrimal apparatus which is responsible for tear production. The tear film is a mixture of mucin, aqueous (water and solutes like NacI, sugar, urea, proteins,), lipids secreted by goblet cells, lacrimal glands, and meibomian glands, respectively. It keeps the eye moist, provides oxygen to the cornea, and has antibacterial properties. The lipid layer prevents the evaporation of the aqueous. DED is categorized into (i)Aqueous-tear deficiency, characterized by a deficiency of lacrimal glands to secrete tears, (ii)Evaporative DED, associated with increased tear loss by evaporation because there is a deficiency of the meibomian glands. The mechanism of DED might be loss of tear through evaporation or insufficient aqueous production or a combination of the two. DED is a widespread eye problem, which is often left untreated. It causes irritation, itching, dryness, foreign body sensation, and discomfort; severe case causes conjunctival congestion, keratinization, erosion of the corneal epithelium, and plaque formation. If left Univision- threatening vision-threatening, leading to complications like corneal ulceration and perforation. Various clinical tests are used to diose DED, including tear breakup time, tear osmolarity, Schirmer test, Rose Bengal staining, and expression of inflammatory markers. There is no cure for DED at present. The following modalities are used for its treatment:
use of punctual and canalicular plugs,
artificial tear products like polyethylene glycol/propylene glycol with guar HP,
consuming food rich in omega-three fatty acids, antioxidants zeaxanthin, and lutein,
Use of anti-inflammatory drugs, mucolytics, secretagogues.
Reducing or avoiding mild risk factors like prolonged reading, prolonged use of contact lenses, excessive screen time, etc.
Treatment of causative disease.
Appropriate management and establishing reasonable patient expectations are necessary to ensure patient satisfaction and adherence to the treatment.
A Rabbit Model of Aqueous-Deficient Dry Eye Disease Induced by Concanavalin A Injection into the Lacrimal Glands: Application to Drug Efficacy Studies