Table 1: Dry eye severity grading scheme.

Dry eye severity level123 4

Discomfort, severity and frequencyMild and/or episodic; occurs under environmental stressModerately episodic or chronic, stress or no stressSeverely frequent or constant without stressSevere and/or disabling and constant
Visual symptomsNone or episodic mild fatigueAnnoying and/or activity-limiting episodicAnnoying, chronic and/orconstant, limiting activityConstant and/or possiblydisabling
Conjunctival injectionNone to mildNone to mild ± +/++
Conjunctival stainingNone to mildVariableModerate to markedMarked
Corneal staining (severity/location)None to mildVariableMarked centralSevere punctate erosions
Corneal/tear signsNone to mildMild debris and meniscusFilamentary keratitis, mucus clumping, and tear debrisFilamentary keratitis, mucus clumping, and tear debris, and ulceration
TFBUT (sec)Variable≤10≤5Immediate
Schirmer score (mm/5 min)Variable≤10≤5≤2

*Must have signs and symptoms; TBUT: fluorescein tear breakup time; reprinted with permission from Behrens A, Doyle JJ, Stern L et al. Dysfunctional tear syndrome. A Delphi approach to treatment recommendations (Cornea 2006; 25: 90–7).