INTERPRETATION OF EYE IRRITATION TESTS TABLE 2--CoRNEAL SCORING 283 A. Opacity-Degree of Density (.4rea Most Dense Taken for Readin,O No opacity Scattered or diffuse area, details of iris clearly visible Easily discernible translucent areas, details of iris slightly obscured Opalescent areas, no details of iris visible, size of pupil barely discernible Opaque, iris invisible B. Atrea of Cornea Involved One quarter (or less) but not zero Greater than one quarter, but less than half Greater than one half, but less than three-quarters Greater than three quarters, up to whole area Total score = A X B X 5 Theoretical maximum = 80 TABLE 3--I. IR•IXA• SCOt,NO o Normal Folds above normal, congestion, swelling, circumcorneal injection (any or all of these or combination of any thereof) iris still reacting to light (sluggish reaction is posi- tive) No reaction to light, hemorrhage, gross destruction (any or all of these) Theoretical maximum = 10 5 TABLE 4--CoNJUNCTIVAL SCOaINC, A. Redness (Refers to Palpebra! and Bulbar Conjunctiva Excluding Cornea andIris) Vessels normal 0 Vessels definitely injected above normal 1 More diffuse, deeper crimson red, individual vessels not easily discernible 2 Diffuse beefy red 3 B. Chemosis No swelling 0 Any swelling above normal (includes nictitating membrane) 1 Obvious swelling with partial eversion of lids Swelling with lids about half closed 3 Swelling with lids half closed to completely closed 4 C. Discharge No discharge 0 Any amount different from normal 1 Discharge with moistening of lids and hairs adjacent to lids 2 Discharge with moistening of lids and hairs and considerable area around eye 3 Total score = (A q- B q- C) X 2 Theoretical maximum = 20 lesions scattered over the four quadrants of the corneal surface will result in a score identical to that of a single, larger, discrete area of complete opacity confined to one quadrant. It should be noted that the total score for cornea is five times the product of the subscores for degree of opacity and area of involvement. It might appear from this scheme that corneal scoring is not overly difficult but in actual practice great care must be exercised to avoid missing minute focal lesions. The use of a fluorescein flush helps considerably in this respect and readily renders visualization of very small superficial lesions which otherwise might be completely overlooked. At least in theory, though again not in practice, iridial scoring is rela- tively simple. It may be divided fairly sharply into three categories:

284 JOURNAL OF THE SOCIETY OF COSMETIC CHEMISTS no irritation, comparatively mild inflammatory alterations and gross damage a score of 0, 5 or 10 is awarded respectively. It may be worth emphasizing here that although the minimum scores for iris and cornea are the same (i.e., 5 excluding zero) the maximum iridial score (10) is only twice the minimum corneal score and only one-eighth of the maximum for the latter. The conjunctiva is scored with regard to redness, swelling and discharge, respectively, in a 3:4:3 (i.e., 1:1. 3:1) irritation emphasis ratio and the total score is twice the sum of the individual subscores for these criteria. The minimum conjunctival score (excluding zero) is 2 and the maximum is 20. T.•BLE 5--REsin:rs or EYE IRRrr.¾r•o• TEs'r (A•m•o R.•Bm'rs) Maxi- mum Rabbit Tissue 1 24 48 72 96 7 Possible Number Scored hr. hr. hr. hr. hr. days Score 1 Cornea 30 Iris 10 Conjunctiva 10 Total 50 2 Cornea 30 Iris 10 Conjunctiva 8 Total 48 3 Cornea 30 Iris 10 Conjunctiva 8 Total 48 4 Cornea 30 Iris 10 Conjunctiva 8 Total 48 5 Cornea 30 Iris 10 Conjunctiva 8 Total 48 30 30 30 20 15 80 10 10 10 10 10 10 10 6 8 8 4 20 50 46 48 38 29 110 30 30 30 20 20 80 10 10 10 10 10 10 4 4 8 8 4 20 44 44 48 38 34 110 30 30 20 20 5 80 10 10 10 10 5 10 4 4 4 4 4 20 44 44 34 34 14 110 30 10 10 10 5 80 10 10 10 10 10 10 4 6 8 8 6 20 44 26 28 28 21 110 30 20 20 20 10 80 10 10 10 10 10 10 6 6 6 6 6 20 46 36 36 36 26 110 Mean scores Cornea 30.0 30.0 24.0 :22.0 18.0 11.0 80 Iris 10.0 10.0 10.0 10.0 10.0 10.0 10 Conjunctiva 8.4 5.6 5.2 6.8 6.8 4 8 20 Mean Total Scores 48.4 45.6 39.2 38.8 34.8 25.8 110 Having discussed the scoring system in some detail, an illustrative example is in order. In Table 5 data for an actual eye irritation test are presented. The test material was an experimental shampoo and the results following the instillation of 0.1 ml. quantities into the eyes of five rabbits are shown. In each instance, the instillation was made undiluted into the conjunctival sac of the right eye. The left eye of each animal served as an untreated, comparative scoring control. Scores are assembled for