Wydanie 3/2008

Powiększenie poprzez zbliżanie

Magnification by Approaching

Sebastian Nowakowski

Ophtalmica Nowakowski Kierownik: mgr Sebastian Nowakowski

Summary: Imagine please, we were waiting at a bus-stop. At last the bus we are waiting for, is coming. At the beginning and still rather far, the bus looks very small, but it seems to enlarge when approaching, and becoming larger and larger, it reveals more and more details like bus number and destination. That?s magnification by approach. In fact this bus of course keeps its size, but by its approaching we see the bus under an increasing angle of vision and proportional to this wider angle of vision, we get a larger retinal image, revealing more details too. Once more: the wider angle of vision causes a larger retinal image, or: there is a reciprocal relation between the distance of an object and its retinal image. The larger the distance of an object, the smaller its retinal image size. Or: the smaller the distance, the larger the image of that object on our retina. That means: half distance causes double size of retinal image. Its consequence in daily life. I mentioned the problems of visual impaired and most elderly individuals in perceiving low contrast objects. You must know, that seeing in low contrast-conditions makes the main point in daily life. Suppose you suddenly perceive a car coming, only with the angle of your eyes, not directly as just looking forward. Filter lenses and a high intensity of lighting often improve these low contrast problems.


powrót

REDAKCJA NIE UDZIELA PORAD MEDYCZNYCH I NIE POŚREDNICZY W KONSULTACJACH PACJENTÓW Z LEKARZAMI