Table 1.

Onychomycosis Severity Index (OSI)

Area of involvement		Proximity of disease to matrix		Presence of dermatophytoma or subungual hyperkeratosis >2 mm
affected nail, %	points	amount of involvement from distal edge	points	present	points
0	0	<1/4	1	no	0
1–10	1	1/4–1/2	2	yes	10
11–25	2	>1/2–3/4	3
26–50	3	>3/4	4
51–75	4	matrix involvement	5
76–100	5

Source: Carney et al. [14].