How to Choose Frames and Lenses for Eyeglasses Frames Metal Frame Plastic Frame It is relatively thin, easily become bent or deformed. The metal can cause skin irritation when sweating and the sweat may corrode the metal surface. Distance between the frame and the face is farther. Most frames have nose pads, which can be adjusted according to the height of the bridge of the nose. It is relatively thick, not easily bent or deformed. It fits students with excessive sweating as skin irritation seldom results from plastics. The frame is relatively close to the face. Most frames are without nose pads and the bridge supports the frame directly with little room for adjustment. Points to Note When Choosing Eyeglasses Frames: 1. Severity of refractive errors: Students with severe refractive errors may choose plastic frames as they are thick enough to cover the edge of the thick lenses for a better look. 2. Width of the face: The size of the frames should match the size of the face and the head. The larger the frames, the bigger and heavier the lenses will be. However, smaller frames mean smaller peripheral vision. 3. Width of the head: The width of the frame should be similar to that of the head so that the arms will not press against the head nor too far from the head. 4. Distance between the eye and the ear: The length of the arm should match the distance between the eye and the ear. Arms that are either too long or too short are uncomfortable. 5. Height of the bridge: Students with flat nose should choose frames with nose pads because these can fix the position of the frame and prevent it from sliding down and being too close to the face, so that it is more comfortable. 6. Habit of removing the eyeglasses with one hand: Students who are accustomed to removing their eyeglasses with one hand should choose frames with spring hinges. These are not easily distorted and damage is usually milder. 7. Style of the eyeglasses: Students may refuse to wear eyeglasses if they don't like the style. Thus, when choosing the eyeglasses, parents should discuss with their children and make sure they accept the need to wear glasses and agree with the style chosen. Eyeglass Lenses Classification of Lenses 1: Plastic lenses, Glass lenses, High Index Plastic Lenses and High Index Glass Lenses. Plastic Lenses Glass Lenses High Index Plastic Lenses High Index Glass Lenses Shatter-resistant Fragile Shatter-resistant Fragile Light Heavy Light Heavy Surface more vulnerable to scratches Surface is scratch-resistant Surface more vulnerable to scratches Surface is scratch-resistant Thick Thin As thin as glass lenses The thinnest Cheaper Cheaper Relatively Expensive Relatively Expensive Classification of Lenses 2: Lenses with or without Anti-reflective Coating Without Anti-reflective Coating With Anti-reflective Coating Plastic or glass lenses, whether high index or ordinary ones Multiple anti-reflective films are coated on the surface of the lenses. No adverse effect on vision Does not help vision No effect on the progression of refractive errors No effect on the progression of refractive errors Reflect part of the light Reduce light reflection and increase the transparency of the lenses Poorer appearance Better appearance and clearer Cheaper Expensive Classification of Lenses 3: Clear Lenses, Rose tinted Lenses and Brown tinted lenses or Gray tinted Lenses Clear Lenses Rose tinted Lenses Brown tinted lenses or Gray tinted Lenses Plastic or glass lenses Plastic or glass lenses, mostly with high prescription power Glass lenses can be tinted brown, while plastic lenses can be tinted in any colour No colour Light red Obvious colour Does not affect the colour of objects The colour of objects looks soft The colour of objects looks dark Does not protect against sunlight Does not protect against sunlight Protect against sunlight Points to Note When Choosing Lenses: 1. Students should choose plastic lenses because glass lenses may break during accidents and cause eye injury. 2. Should get used to cleaning the lenses with appropriate lens cloth instead of tissues, shirts or other materials so as to avoid scratching the lens. 3. If the anti-reflective coating comes off, the lens will look worse than ordinary uncoated lens and the vision will be affected. 4. To address the weakness of being easily scratched, a scratch-resistant film can be coated to the surface of plastic lenses, though the effect is not ideal and the surface of the lenses are still not as hard as glass lenses. 5. If the lenses are severely scratched, they should be replaced as soon as possible to avoid the vision being affected.