1. The dark adaptation of the cones of the amblyopic eye is somewhat reduced.

2. The dark-adaptation curve is biphasic, the first segment being higher than in normal subjects (global thresholds).

3. Testing revealed reduced visual acuity, adversely affected color discrimination, visual field defects, and a monophasic, “photopic” dark adaptation.

4. Good discrimination of the OP with a concurrent diminution in the amplitudes was only observed after a pre-dark adaptation.

5. The cisternae, probably composed of agranular endoplasmic reticulum undergo swelling during dark adaptation and appear in frequent connection with Golgi cisternae.

6. Electroretinographic responses obtained from carriers of achromatopsia revealed a selective a-wave abnormality. Low a-wave amplitudes were found throughout the course of thirty minutes of dark adaptation.

7. Using an amplitude criterion the sensitivity profile for equal retinal fields of different eccentricities closely corresponded to the rod density after dark adaptation and to the cone density during light adaptation.

8. The study of the dark adaptation and of the critical frequence of fusion of amblyopic patients leads to the conclusion that the causal lesion of amblyopia is situated over the calcarine fissure, probably in the superior centers of vision.

9. Prototypical symptoms are the omission of obstacles and hemianopic alexia in visual field disorders, blurred vision in reduced acuity and/or contrast sensitivity or impaired fusion, blinding in impaired light adaptation and dark vision in impaired dark adaptation, and impaired action and orientation in visuospatial deficits.

10. The cases with complete congenital achromatopsia presented a uniform picture: the subjects affected were not able to distinguish colours at all; the ERG showed subnormal amplitudes of a- and b-waves and a flicker fusion frequency with a maximum of 10 cps according to the lack of photopic components; the course of dark adaptation was monophasic within the normal range or near to it.