Defective ocular movements and their diagnosis / by E. and M. Landolt ; translated by Alfred Roemmele and Elmore W. Brewerton.

  • Landolt, E. (Edmond), 1846-1926.
Date:
1913
Catalogue details

Licence: In copyright

Credit: Defective ocular movements and their diagnosis / by E. and M. Landolt ; translated by Alfred Roemmele and Elmore W. Brewerton. Source: Wellcome Collection.

Provider: This material has been provided by UCL Library Services. The original may be consulted at UCL (University College London)

    18/108 (page 14)
    between the two centres of rotation (00', Fig. 6), which is called the base line. In children with a base line (B') of 58 mm. in length the metre angle is 1° 40' = 100'. In adults with base line (B) of 64 mm. in length the metre angle is i'5o° = 110'. To convert metre angles (m.a.) into ordinary angles [x), all that is necessary in the first case (B') is to multiply the metre angles by 100, in the second case (B) by 110, and divide by 60. 1^ -D/ 10 m.a. 5 m.a. For B : :v = —^— = ^ 6 3 For B : X = — o 9 metre angles, for example, would correspond in children to = I = 15°. In adults >< 9 ^ ,6-5°. 6 6^ 6 ^ Conversely, to find the number of metre angles which correspond to a given angle [x), we write— For B' (base line of 58 mm.) m.a. = =:^. ^ 10 5 6x For B (base line of 64 mm.) m.a. = —. ^11 Example : 3° of convergence is equivalent in children to ^ = i'8 metre angles. 10 ^ In adults to = 1*63 metre angles. These figures always refer to the excursion of one eye only; to obtain the excursions of both eyes, that is to say the total angle of convergence (or divergence), we must multiply our result by 2. If, for example, a convergence of 9 metre angles was manifest wholly in one eye, the other looking straight