Fig. 2—To Obtain Plano.
| 1— | Set spherical indicator at “000” as illustrated above. |
| 2— | Set cylinder indicator to “0”. |
| 3— | Set pointer of supplementary disk at “open”. |
The instrument should then be set at zero or “plano,” a position indicated by the appearance of the three “0 0 0” at the spherical register, in conjunction with one “0” or zero, for the cylinder at its register, marked “CC Cyl.”
After this move, the supplementary disk’s pointer should be set at “open” ([Fig. 2]).
Fig. 3—To obtain sphericals, turn this Single Reel as shown by dotted finger. This assures an automatic and simultaneous registration at sphere indicator of focus of lens appearing at sight opening.
Convex Spherical Lenses
A careful study will show that the Ski-optometer’s spherical lenses are obtained by merely turning the smaller reel ([Fig. 3]). The first outward turn of this reel, toward the temporal side of the instrument, draws into position in regular order the spherical lenses +.25, +.50, +.75, and +1.D., as shown in [Fig. 3a].
3-A—Outer spherical reel containing Cx. sphericals
from .025 to 1.00D and a blank.