Dr George E. Deschweinitz of Philadelphia, read (by invitation) a paper on ocular headaches. Eye strain due to refractive error, heterophoria and accommodative dysfunction, is responsible, in whole or in part, for about 60 per cent of functional headaches; small error of refraction are often more potent in this respect than the larger ones; all types of refractive error and muscle imbalance are capable of causing headache, simple and compound astigmatism and hyperphoria being the most potent refractive defects in this list.
A look at the past . . .. Arch Ophthalmol. 2001;119(5):717. doi:10.1001/archopht.119.5.717