State of Vision Not Important Factor 223
so many cases which were not benefited by training de signed to improve the fusion faculty that he recom mended operations on the muscles in such cases; while Donders, noting that the majority of hypermetropes did not squint, was obliged to assume that hypermetropia
No. 1-Reading the Snellen test card with normal vision; visual axes parallel.
No. 2-The same patient making an effort to see the test card; myopia and convergent squint of the left eye have been produced.
did not cause this condition without the aid of co-oper ating circumstances.
That the state of the vision is not an important factor in the production of squint is attested by a multitude of facts. It is true, as Donders observed, that squint is usually associated with errors of refraction; but some people squint with a very slight error of refraction. It is also true that many persons with convergent squint