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FIG.

I Parallel rays of light converged....

2 Divergent rays of light paralleled..

3 Acetylene gas lamp with metal chimney..

4 Asbestos lined metal chimney.....

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5 Asbestos lined glass chimney................

6 Asbestos-paper chimney-cover with iris diaphragm opening.. 33

7 Spiral filament in electric lamp..

8 Author's asbestos covered electric lamp.............

9 DeZeng electric retinoscope.....

10 The "Hardy" wall bracket for gas or electric lamp...

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18 DeZeng-Standard schematic eye......

19 Queen's pasteboard schematic eye.....

20 Two cylindric lenses of unequal focus and axis.....

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A crossed cylinder-lens of unequal meridional focus....... 22 Three cylindric lenses of equal focus, one at axis 90, and two at axis 180...............

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23 One crossed cylinder of equal meridional focus and one simple cylinder at axis 180.....

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24 Crossed cylindric lens of plus and minus curvatures.

25 Three cylindric lenses, two plus and one minus....

26 Illumination of second card through hole in first one.....

27 Return rays from second card entering eye through tube in candle

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28 Substituting a skiascope for candle tube...

29 Illuminating the ocular fundus.......

30 The illuminated area on the fundus....

FIG.

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31 Rays returning from edge of illuminated area on the fundus... 65

32 Returning rays influenced by a convex lens....

33 Why the shadow moves "with" the mirror....

34 Why the shadow moves "against" the mirror..

35 Pupillary appearance of a so-called "shadow”.

36 Why the retinal illumination is larger in ametropia than in emmetropia

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37 Why shadows move slower in ametropia than in emmetropia.. 75 38 Why a shadow is duller in myopia than in a like degree of hypermetropia

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39 Relative size of retinal illumination in high and low degrees of myopia ....

40 The optical principles of penumbra..

41 The optical principles of penumbra doubled..

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42 Interference of penumbra in shadow testing...

43 True myopia (Static Method)

44 Artificial myopia (Static Method)......

45 Accommodative myopia (Dynamic Method)......

46 How the accommodation can absorb a ciliary spasm.....

47 Multiple fixation and observation points.....

48 Author's fixation stand.................

49 Fixation stand target card....

50 Reverse side of fixation card....

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51 Position for initial examination......

52 Balancing the accommodation and convergence in emmetropia. 104 53 Equal innervation necessary to balance accommodation and convergence in emmetropia.....

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54 Imbalance of accommodation and convergence in hypermetropia

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55 Unequal innervation required to balance accommodation and convergence in hypermetropia.............

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56 Imbalance of accommodation and convergence in myopia.... 107 57 Unequal innervation required to balance accommodation and convergence in myopia....

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