Retroillumination of the lens (Brückner’s test)is thequickest pre-liminary examination method for lens opacities.Under a light source or ophthalmoscope (set to 10 diopters), opacities will appear black in the red pupil (Fig. 7.5). The lens can be examined in greaterdetail and in three dimensions underfocal illumination with a slit lampwiththe pupil maximally dilated. The extent, type, location, and density of opaci-ties and their relation to the visual axis may be evaluated. Mature lens opacities may be diagnosed with the unaided eye by the presence of a white pupil (leukocoria).
Where the fundus is not visible in the presence of a mature lens opacity, ultrasound studies (one-dimensional A-scan and two-dimensional B-scan studies) are indicated to exclude involvement of the deeper struc-tures of the eye.
Tremulous motion of the iris and lensobserved during slit-lamp examination suggests subluxation of the lens.