SEARCH RESULTS FOR: Dry-Eye-Syndrome-Clinical-Findings

Dry-Eye-Syndrome-Clinical-Findings

Dry Eye Syndrome (Keratoconjunctivitis sicca): Clinical Findings If dry eye is chronic or severe (e.g Sjögren’s syndrome) corneal ulcerations or scarring may occur Impaired visual acuity/ Blindness (does not improve with lubrication) See Calgary Guide: “Dry Eye Syndrome (Keratoconjunctivitis sicca): Pathogenesis” for explanation of etiology and pathogenesis Dry Eye Syndrome (Keratoconjunctivitis sicca): Disease of the ocular surface and tears characterized by loss of tear film homeostasis, tear film hyperosmolality and inflammation Tear film instability & hyperosmolarity Ocular surface inflammation: Immune cell (specifically T-Cell) destruction of corneal and conjunctival epithelium ↓ quantity and/or quality of tear film Inflammatory factors vasodilate conjunctival vessels, making the eye look redder in appearance Conjunctival injection Red eye Corneal surface irregularities Light rays pass through disrupted tear film and ocular surface structures as they enter the eye Degraded image quality as light passes through the eye Impaired visual acuity (improves with lubrication) ↓ lubrication over the eye surface ↑ friction on the eye during blinking or when opening eyes after sleep May cause corneal abrasion (See Calgary Guide: Corneal Abrasion) ↑ stimulation of corneal and conjunctival nerve endings Irritation and damage to corneal and conjunctival cells ↑ stimulation of nerve endings Chronic inflammation surrounding corneal nerves in conjunctiva and epithelium can lead to decreased neuronal firing thresholds (Neurosensory dysfunction / hyperalgesia) ↑ activity of the afferent portion of corneal reflex arc (responsible for reflex tearing: tearing in response to irritation of the eye) Foreign body sensation (scratching / feeling as if a foreign body, like a grain of sand, is in the eye) Minor (typically non-painful stimuli) may cause pain due to hypersensitive corneal nerves Corneal neuropathic pain (pain not fully explained by ocular surface changes, often resistant to standard treatments, sometimes still present following ocular surface anaesthesia if central pathways affected) Pain with temperature change and wind exposure Exact mechanism unknown Photophobia Burning sensation Paradoxical reflex tearing (↑ tearing, which does not improve dry eye due to altered tear composition, poor surface coverage or overflow of temporary tearing out of the eye Authors: Michael Penny, O.D. Davis Maclean Yan Yu* Reviewers: Natalie Arnold Saleel Jivraj, O.D. Adam Muzychuk* Victor Penner* *MD at time of publication Legend: Pathophysiology Mechanism Sign/Symptom/Lab Finding Complications Published August 6. 2021 on www.thecalgaryguide.com