=Accommodation= in the eye is the ability of the eye to vary its focal point. When the normal eye (emmetropic) is at rest its focal point is at infinity so far as parallel rays are concerned. This is called the far-point or the “=punctum remotum=” (P. R.). When the eye looks at letters twenty feet away it scarcely accommodates at all to get a focus, or so little that it may be disregarded in ordinary practice. Now if one brings fine print close to the eye he will find a point so close that it becomes indistinct. This point is the near-point of focus or the =“punctum proximum”= (P. P.). The range of accommodation is the difference between the refractive power of the eye when it is at rest and when the accommodation is exerted to the utmost, the difference between the P. R. and the P. P. If one must accommodate one diopter to get a focus at one meter or forty inches distance, at thirteen inches or reading distance one must accommodate at least 3 D in order to see the letters clearly. If 3 D were the total of his accommodation he could not read at that distance but a few minutes; because the accommodation could not be held at its maximum for long at a time. Eye strain with its train of symptoms would result. Hence it is quite important to find the near-point or punctum proximum in order to judge in regard to eye strain in an emmetropic eye. If there is a refractive error, allowance for it must be made accordingly. As a person gets older the accommodation in the eye becomes less and less until at 45 years of age he can only use 4 to 5 D of accommodation. This is so close to the amount required for reading that he has some eye strain. He begins to hold his paper farther away from him so he requires less accommodation. This condition we call “old sight” or =presbyopia.= An emmetropic eye at forty-five to fifty years of age requires a plus glass to make up for some accommodation in reading. Frequently there are latent disturbances of equilibrium of the extrinsic muscles of the eye. This is =heterophoria.= If it is a latent convergence it is =esophoria=; if a latent divergence it is =exophoria=. The latter is more frequent. Hyper- and hypophoria are used for upward or downward tendencies. Normal muscular balance is =orthophoria=. Cause the patient to fix on an object about thirteen inches away with both eyes; push a sheet of paper in front of one eye and watch behind the paper, the eye thus covered. If heterophoria exists the eye will move slightly from its point of fixation since it no longer sees the object. In orthophoria it will remain fixed as long as the other eye sees the object; the innervation to the different muscles is properly distributed.