DISORDERS IN RELATION TO THE EYE 781 



the endocri-n balance, reduces to an almost negligible minimum the ocular 

 affections which can be brought into a dependence on disease of the 

 sexual apparatus per se. The hysterical manifestation, such as asthenopia, 

 kopiopia hysterica, or accommodation spasm are largely expressions of an 

 ocular vagotonia (q. v.) which is but part of the general spasmophilia 

 indicated by globus hystericus, headaches, stomach cramps, constipation, 

 acidosis, and so on. 



Intoxications. Exogenous poisons, inorganic and organic, as well 

 as poisonous products of disease processes and of disorders of metabolism 

 have a marked effect on the visual functions. Many have a selective af- 

 finity for the optic nerve, notably lead, quinin, nicotin, morphin and some 

 other alkaloids. The coincidence of pupillary contraction and of spasm 

 of accommodation with general arterial contraction in the retina and nerve 

 suggest, again, the factor of vagotonia. The mydriatic group, on the other 

 hand, acts as a sympathetico-tonic or vago-depressant and the resulting 

 symptoms are limited to the pupil and ciliary muscle while the function of 

 the retina and nerve do not seem to be affected. 



Ocular Morphology 



The size of the eyeball as well as its axial proportions which very 

 largely determine whether it is to be myopic or hypermetropic depend in 

 great measure on the dimensions of the orbit and indirectly on those of the 

 skull, particularly the area at the base in the neighborhood of the sella 

 turcica. The ethnologic divisions of long-skulled and short-skulled races 

 are paralleled by the categories, of more importance to the ophthalmologist, 

 of chamai-conchs and hypsi-conchs (Stilling), according to the relatively 

 high or low position of the pulley for the tendon of the superior oblique 

 muscle on the inner (nasal) and upper aspect of the orbital cavity. 

 According to Stilling, this mechanically determines the growth and pro- 

 portions of the globe by directing the pressure upon it of the extrinsic 

 ocular muscles during its pliable period of development in the act of fixa- 

 tion, especially in convergence. While this mechano-physical control 

 may explain the relation of orbit to eye-form, there does not seem to be 

 any corresponding theory to elucidate the variety (variation) in the devel- 

 opment of characteristic, racial, skull-forms. The endocrin element, and 

 above all the pituitary, is of prime importance. Apart from its influ- 

 ence on rhythm and tempo of growth, the mechanical proportions of this 

 gland cannot be without influence on the dimensions of the sella and in- 

 directly on those of the orbit, and a pituitary dominance within the bounds 

 of the physiological will be indicated by typical ocular morphological fea- 

 tures. Conversely, a deficiency of pituitary control will result in a type 

 of eye which provisionally I shall describe as hyperthyroid. 



