(_a_) In myopia, emmetropia, and doubtful hypermetropia, with convergent and divergent squint together 329 cases. Among them: Visual acuteness to 1/7 239 " less than 1/7 to V. 1/12 19 " " 1/12 to V. 1/36 46 " " 1/36 25 Defective sight of higher degree than 1/7, 27·3 per cent. (_b_) In hypermetropia 1 to 3 D., including the few cases of hypermetropia with divergent squint, 177 cases. Among them: Visual acuteness to 1/7 121 " less than 1/7 to V. 1/12 17 " " 1/12 to V. 1/36 27 " " 1/36 12 Defective sight then, 31·6 per cent. (_c_) In hypermetropia 3 D. and more, 70 cases with convergent squint, with: Vision to 1/7 39 V. < 1/7 to V. 1/12 8 V. < 1/12 to V. 1/36 14 V. < 1/36 9 Defective sight then, 44·2 per cent. This regular increase of defective sight with the increase of the hypermetropia can be no mere accident, and speaks strongly for the identity of defective vision in squint with congenital amblyopia. Were defective vision caused by the squint the various states of refraction would show no difference in the percentage of defective vision. Further, the circumstance is worthy of remark that among 198 cases of periodic squint (convergent and divergent) which are applicable for the statistics of visual acuteness-- 170 possess V. to 1/7. 16 " V. < 1/7 to V. 1/12. 9 " V. < 1/12 to V. 1/36. 3 " V. < 1/36. 14·2 per cent. then of defective vision of considerable degree.