If right eye is defective: Two letters: DO
If left eye is defective: Two letters : OG
Ocular imbalance: DOG
This apparatus is used for training the ocular muscles and developing sight in squint and amblyopic eye.
Method: The head is comfortably supported on the forehead rest, the whole instrument being tilted to ensure correct head posture and the eyes look into a pair of spherical lenses. The double-sided mirror may be inclined to the left or to the right. The picture acrrier is designed to fit on to either side of the instrument.
Figure 52: Maddox Cheiroscope