Table 3. Photo-diagnosis of corneal opacity: slit lamp subgroups.

Eye-level data are shown for cases with a slit lamp examination, stratified by the photo-grader’s assessment of (a) the suspected cause of the scar and (b) the size of the scar on photography, and by the slit lamp examination assessment of (a) size and (b) location. For assessing the suspected cause, the typical infectious keratitis scar was considered to be a single, round lesion and the typical nummular keratitis scar was considered to be comprised of numerous small round opacities distributed across the cornea. Controls are not included because not all the controls had photo-grades available.

	Slit lamp examination
	Sizea					Location
Photo-grade	Tiny	Small	Medium	Large	None	Central	Peripheral	None
No opacity	17	10	1	0	81	13	15	81
Suspected cause
Infection	23	21	8	4	28	36	20	28
Nummular	8	12	3	0	11	13	10	11
Other	0	1	2	3	7	4	2	7
Size categoryb
Tiny	2	0	0	0	4	1	1	4
Small	25	25	5	0	31	30	25	31
Medium	4	8	5	0	9	12	5	9
Large	0	1	3	7	2	10	1	2

^aSize measured at the slit lamp as geometric mean of longest length and longest perpendicular width; categories defined as tiny (<1 mm), small (1–3 mm), medium (3–6 mm), and large (≥6 mm).

^bSize measured on photographs as the proportion of the total cornea area occupied by the scar, which was subsequently classified as tiny (<0.5 mm), small (0.5–3 mm), medium (3–6 mm), and large (≥6 mm) assuming a circular scar and 11 mm corneal diameter.