pine for long periods-Evidence of these cases against accepted theories overwhelming-Cases of accommo dation in lenseless eyes observed by author-Reality of the apparent act of accommodation demonstrated by the retinoscope-Evidence from the cure of presbyopia- Harmony of all clinical observations with views of accommodation and errors of refraction presented in this book.
CHAPTER VII The Variability of the Refraction of the Eye . . 75
Refractive states supposed to be permanent-Retino scope demonstrates the contrary-Normal sight never continuous-Refractive errors always changing--Condi tions which produce errors of refraction-Variability of refractive states the cause of many accidents-Also of much statistical confusion.
What Glasses Do to Us.......81
The sins of Salvino degli Armati reputed inventor of spectacles-How glasses harm the eyes-Sight never improved by them to normal-Always resented at first by the eye-Objects of vision distorted by them-Disa greeable sensatoins produced-Field of vision con tracted-Difficulty of keeping the glass clean-Reflec tion of light from lenses annoying and dangerous- Inconvenience of glasses to physically active persons- Effect on personal appearance-No muscular strain re lieved by them-Apparent benefits often due to mental suggestion-Fortunate that many patients refuse to wear them-At best an unsatisfactory substitute for normal sight.
Cause and Cure of Errors of Refraction ... 89
All abnormal action of external muscles of the eyeball accompanied by a strain to see - With relief of this strain all errors of refraction disappear-Myopia (or lessening of hypermetropia) associated with strain to see at the distance - Hypermetropia (or lessening of myopia) associated with strain to see at the near-point -Facts easily demonstrated by retinoscope-Effect of strain at the near-point accounts for apparent loss of accommodation in the lenseless eye-Mental origin of eyestrain-Accounts for effect of civilization on the eye -Lower animals affected as man is-Remedy to get rid