Historical Facts Lenses | Glasses | Contact Lenses | Telescopes | Microscopes Lenses As you can guess, a lens doesn’t always have to be glass. Thefirst lens was a container of water. It was discovered by the ancientRoman writer Seneca (4 B.C.-65 A.D.?). He found that images becamemagnified when seen through a glass ball filled with water. Roger Bacon (1214-1292?) invented the first convex lens in 1250. Concave lens were first used around 1450. Glasses Glasses were used in Italy around 1300. Old glasses were fastened withclips, rings, ribbons, weights, and other flexible things, or weresimply held by the hand. Temples weren’t invented yet! They had framesof tortoiseshell, ivory, metal (heavy metal), or wood. They were prettyheavy. Temples were finally invented in the 1740’s. Lorgnettes(pronounced lorn-YETS ) were also popular in the late 1700s. This word comes from the French word lorgner , meaning to leer at or stare. These were glasses held by a handle. ...
1- Emetropia العين التي لا يوجد بها عيب بصري 2- Ametropia العين التي بها عيب بصرى A- قصر النظر Myopia (Nearsightedness) B- Hyperopia (Farsightedness) طول النظر C- لا نقطية أو لابؤرية Astigmatism - أنواع اللانقطية Astigmatism Types - d نقص التكيف Presbyopia * تفسير الأخطاء الانكسار بالعينالبشرية RefractiveErrors 1- العين التي لا يوجد بها عيب بصري Emetropia وهى الحالةالتى ليس بها أى خطأ إنكسارى RefractiveErrors وبالتالى يتجمع الضوء المنكسر Refracted على الشبكية Retina وذلك بدون آى تكيف Accommodation لذا فهذه العين لاتحتاج إلى تصحيح Correction . 2- العين التى بها عيب بصرى Ametropia وهى الحالةالتى بها خطأ إنكسارى RefractiveError وبالتالى لا يتجمع الضوء Light على الشبكية Retina بدون آى تكيف Accommodation وهى تنقسم إلى أربعة أنواع :- - قصر النظر Myopia - طول النظر Hyperopia - لانقطية (لابؤرية) Astigmatism - نقص التكيف Presbyopia - نود لفت الإنتباه بأ...
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