Table 4.

 Statistical test results of comparisons of incidences of non-severe and severe keratitis

Modality of wear Lens type	Type of keratitis	Daily wear Hydrogel daily disposable		Daily wear Hydrogel		Daily wear Silicone hydrogel		Extended wear Hydrogel		Extended wear Silicone hydrogel
		χ2	p Value	χ2	p Value	χ2	p Value	χ2	p Value	χ2	p Value
Daily wear Rigid	Non-severe	0.4	0.46	3.2	0.09	6.3	0.12	8.7	0.04	48.6	0.0001*
	Severe	0.5	0.73	1.2	0.40	†	†	42.4	0.0001	6.1	0.04
Daily wear Hydrogel daily disposable	Non-severe			2.1	0.15*	4.0	0.16	6.1	0.06	67.0	0.0001*
	Severe			0.4	0.53*	†	†	47.6	0.0002	5.0	0.06
Daily wear Hydrogel	Non-severe					2.2	0.23	3.3	0.12	57.3	0.0001*
	Severe					†	†	43.7	0.0003	3.7	0.09
Daily wear Silicone hydrogel	Non-severe							0.0	1.00	0.3	1.00
	Severe							†	†	†	†
Extended wear Hydrogel	Non-severe									1.0	0.55
	Severe									5.3	0.04

*p value determined using χ² test (all other p values determined using the Fisher’s exact variant of the χ² test).

†Indeterminable because of the absence of severe keratitis with daily wear silicone hydrogel lenses.