What Are the Disadvantages of High-Index Lenses?
This section will show high index lenses disadvantages.
- High index lenses are made from a chemical synthetic blend that’s created through a special manufacturing process. So, high index lenses are expensive than regular lenses. In fact, the price may be more than double that of the traditional counterparts.
- High index lenses can be more brittle than their traditional counterparts and may also be more prone to scrapes and scratches. This can impact their overall durability.
- High index lenses are more reflective than regular lenses, which can make them less effective for brightly lit work environments, outdoor use and nighttime driving on busy highways.
- High index lenses have greater potential for distortion, particularly in your peripheral vision because the high index lenses have a higher Abbe value than prescriptions made from standard plastic or glass.
What Is a Prism in Glasses?
Prism is triangular and made of plastic or glasses for the purpose of dispersing light into a spectrum or changing the direction in which light is reflected.
Prism lenses are special lenses that are prescribed by eye doctors and infused into regular lens prescriptions. The prism glasses do not include contain any focusing power, and therefore cannot any refractive errors. So, one of the most common uses for prism glasses is to correct diplopia or double vision. Double vision means someone sees two separate images of a single object. The prism glasses help to align the two images and correct the problem. The prism glasses can be used to improve binocular vision and reduce double vision, headaches, reading difficulties, and so on.
Seek adjustment in stores
It occurs redness and pain in the ear area. It could be that the structure of the glasses and position doesn't suit your face shape. When you're in an optician's shop, ask an optician for help in adjusting your glasses or changing the frames. Think about if the frames fit or are a little heavy. Suggest you can change to another pair. You should try a suitable and not heavy frame. You go back to the eyewear store and ask a professional to shape your frame in accordance with the outline of your ears again carefully. If you feel a little uncomfortable when you try it on, adjust it.
Problems you may encounter when wearing your glasses.
The glasses are too tight. They clamp to the temple. Glasses slip easily. Too long or too short at the bend, and there are too small contact areas of the nose pad. Glasses are too far from the eye, and the lenses are crooked or asymmetrical. These are some of the problems you may encounter when wearing glasses.
Take Frame material selection seriously.
When choosing a frame, try to choose a light frame. At present, the glass frame material is relatively light titanium, tungsten carbon, TR90, and so on. Now based on the plate spectacle frame, the new plate spectacle frame implements thin processing, so the whole spectacle frame has become light up. You can use rimless light glasses. Usually, the nose pad will leave an indentation, possibly because the glasses are too heavy. Changing some light glasses can improve the problem of indentation of the nose pads.
The benefits of bifocal glasses
People with myopia often need to wear bifocal glasses after the appearance of presbyopia. The upper and lower parts of the lens have different diopters. The upper part is used to see distant objects, and the lower part is used to read and do close work. In addition to presbyopia, some people who work long hours in close quarters need bifocals to reduce eye strain. Studies have shown that long-term nearsightedness is the main cause of myopia. According to the adjustment principle of the eyeball and the height of the patient diopter, a reasonable measure is to wear myopia glasses with full correction when seeing the blackboard in class. When reading and writing. they should take off glasses or wear low myopia glasses. But the practice of continuously removing and putting on or changing glasses is clearly unrealistic. Bifocal glasses will solve this problem.
The disadvantages of progressive lenses
- The field of view in the near and middle distances is relatively narrow.
- The adaptation time is longer and patients with greater astigmatism are not suitable for wearing.
- The peripheral aberration is large, and there will be large astigmatism in the periphery.