Table 1.

Approach to understanding risks related to microbial keratitis based on modifiability and certainty of evidence.

	Consistent	Probable	Inconclusive
Non-modifiable	Gender	Shorter duration of lens wear	Dry eye
	Younger adult age	Diabetes	Thyroid disease
			Season
			Race
			Myopia
			Self-reported poor health
			Socio-economic class
			Prior red eye event
Modifiable	ANY overnight wear	Case replacement frequency	Lens age (Fusarium)
	Increasing duration of overnight wear	MPDS vs H2O2	Replacement frequency
	Contact with tap water	Swimming without goggles	Ophthalmologist fitting
	Case hygiene	Cosmetic/colored CL use	Lens material type (daily disposable)
	Solution type (Complete/ReNu MoistureLoc)	Degree of exposure in daily wear	Orthokeratology contact lens use
	Infrequent disinfection/topping off	Internet purchase	Use of lenses on holiday
	Overall compliance score	Solution type (Oxipol)	Failing to rub lenses on removal
	Not handwashing prior to handling		Group IV contact lenses (in combination with certain solution types)
	Smoking
	Lens other than RGP