IRIS PIGMENT DEFECTS IN NORMALS

Defects of the iris pigment layer have been studied in normal eyes by means of transpupillary transillumination according to Abrams. Defects were detected near the pupil and in the pupillary ruff. Such defects were seen in none of the normal subjects aged under 45, but were increasingly frequent in the older age‐classes (5 per cent irides with pigment layer defects and 12 per cent with pupillary ruff defects in the age‐class of 45–50, against 72 and 56 per cent respectively among the normals aged over 80). The defects were most often found infero‐nasally. The defects near the pupil consisted in half of the cases of few punctate holes, and in the other half of more than five holes, of larger holes, or confluent holes. A knowledge of such defects in normals is required before it is possible to assess whether defects in a given patient may be signs of a pathological condition (uveitis, acute glaucoma, injury, etc.) or merely indicate a physiological, age‐determined wear and tear within the pupillary region. In addition to the defects described above, transparency within a sector inferiorly in the iris was seen in 4 per cent of the normal series. This phenomenon may, perhaps, be interpreted as an abortive coloboma of the posterior lamina of the iris.