andreajo
Critical Thinker
- Joined
- Nov 5, 2013
- Messages
- 307
As someone very interested in photography, I can tell you that in optimum lighting conditions a constricted pupil does not effect the ability to see at a distance. However, it absolutely does effect the ability to see at a distance in less than optimum lighting conditions. The constricting or dilation of the pupils control the amount of light to hit the retina. Too much light and the person is blinded by light, too little light and you can't see either.
So during the day, Toto's distance vision would NOT be impaired, but at night it would in fact be severely impaired. The best way to understand this would be to adjust a camera's shutter settings and take pictures. Closing the shutter opening in the daytime could improve the quality of the picture, making it look less washed out and actually improve the image.
However, at night, you need all the light you can get. So when taking pictures at night the first thing you do is open the shutter all the way trying to get as much light as possible to the film or the CCD. This is why our eyes dilate at night. They are trying to allow as much light as possible to reach our retinas. Constricted pupils at night would have the effect of turning over head lights into candles. Toto's ability to see detail at night at any distance would be significantly worse than the average person.
Was he wearing bifocals or reading glasses? At his age, the lenses do not easily change from reading a newspaper to seeing someone across the park. My parallel experience would be hemming pants and then looking up and trying to see the TV.
In any case, I think his memory might be more of an issue than his eyes...