Strain in Lensless Eyes 95
from this condition through emmetropia, in which it is spherical, to hypermetropia, in which it is flattened; and if these changes take place unsymmetrically, astigma tism will be produced in connection with the other con ditions. The eye which strains to see at the distance, on the contrary, becomes longer than it was before in one or all meridians, and may pass from the flattened condi tion of hypermetropia, through emmetropia, to the elon gated condition of myopia. If these changes take place unsymmetrically, astigmatism will again be produced in connection with the other conditions.
What has been said of the normal eye applies equally to eyes from which the lens has been removed. This operation produces usually a condition of hypermetro pia; but when there has previously been a condition of high myopia the removal of the lens may not be suffi cient to correct it, and the eye may still remain myopic. In the first case a strain to see at the distance lessens the hypermetropia, and a strain to see at the near-point increases it; in the second a strain to see at the distance increases the myopia, and a strain to see at the near-point lessens it. For a longer or shorter period after the removal of the lens many aphakic eyes strain to see at the near-point, producing so much hypermetropia that the patient cannot read ordinary print, and the power of accommodation appears to have been completely lost. Later, when the patient becomes accustomed to the sit uation, this strain is often relieved, and the eye becomes able to focus accurately upon near objects. Some rare cases have also been observed in which a measure of good vision both for distance and the near-point was obtained without glasses, the eyeball elongating suffi ciently to compensate, to some degree, for the loss of the lens.