How to determine whether progressive lenses are worn correctly?
Once your glasses are back from the lab, the optometrist will let you put them on for an audition and make final adjustments to make sure they fit. If the prescription is not in the center of the lens, it will make it difficult for you to see clearly. The key is that the lenses match the wearer's eyes, especially the pupils. Before ordering a new lens, the optometrist takes two measurements: pupil distance and fitting height.
Is titanium alloy necessarily worse than pure titanium?
In the common case, the introduction of a titanium frame will have a detailed material label, what titanium and what material is it made of, such as titanium nickel alloy, titanium aluminum vanadium alloy, and so on.
The composition of titanium alloy determines the quality and price of the frames.A good titanium frame is not necessarily worse or cheaper than pure titanium.It is difficult to ensure the quality of titanium alloy which is very cheap in the retail market.In addition, titanium alloy is not to reduce the cost, but to improve the performance of the material.Usually, the memory frame on the market is made of titanium alloy.
The Disadvantages of Aspheric Lenses
Here, we will show some disadvantages of aspheric lenses.
The aspheric lens has a relatively small light area. When the eyeball rotates around, it will blur a little when looking at the outside through lens edge. In other words, the visual range of the line of sight becomes smaller.
Human’s eyeball is spherical and the eyeball rotates to the edge. Through aspheric lenses, the objects near the eye appear protruding.
What is the cheapest way to buy prescription glasses?
Optometry must be accurate. Optometry is the main basis for glasses. The accuracy of optometry is directly related to the success rate of the glasses prepared. Optometry must be accurate first, and the difference between the upper and lower levels should not exceed 12.5 degrees of the prescription. Secondly, the astigmatism axis should be accurate, and the general axis difference should be limited to plus or minus l to 3 degrees. In addition, the interpupillary distance must be accurate, and the interpupillary distance must be equal to the optical center distance of the lens. If you do not pay attention to the above-mentioned checkpoints in optometry, the prepared spectacle lenses will have blurred vision, prolonged visual fatigue, dizziness, nausea, and even diplopia. Optometry is best to go to a professional eye hospital. For children’s optometry or to wear glasses for the first time, you must use mydriatic optometry to be accurate. You can also check if there is any problem with the fundus, and go to the hospital to get more accurate optometry.
Advantages of progressive multifocal lenses
The progressive multi-focal lens has a number of different focal points from top to bottom. There's a smooth transition between seeing far and seeing close. There is no clear dividing line in the middle, like the myopia glasses, quite beautiful, and it is not dangerous. Because the added value is continuously and slowly increased in the gradient area, the wearer can get a continuous clear vision from the far point to the near point through the progressive lenses with the appropriate head position. In line with physiological optics, They help a better adaptation. Since the lens degree changes little by little, there is no phenomenon like jumping. Because the degree of the lens is gradual, so the vision from far to near changes slowly increase, which will not produce the adjustment of the eye fluctuation. It is not easy to cause visual fatigue. Without a degree line, the appearance will be more beautiful. Clear vision can be obtained at all distances within the visual scope. A pair of glasses satisfies both close and middle distances.
What Are Trifocal Glasses?
Trifocal glasses and no-line progressive lenses are multi-focal glasses, meaning that their lenses offer multiple correction fields. Whether you have been wearing multi-focal glasses for a while, or you have just begun to look at options for correcting vision after 40 years old, you may have heard the terms trifocal or progressive glasses.
Trifocal glasses have three different corrective lenses within one lens to offer you intermediate, distance, and near correction. Trifocal lenses look and perform similar to bifocal lenses, with an added viewing zone to help correct vision in the intermediate field, and two visible lines where the viewing zones change.
How to drive at night with glasses?
If you need to wear glasses while driving, you'll need special glasses when driving at night, because common lenses reflect oncoming lights, which produces a faint glare. This will reduce your visibility. It's OK to wear contact lenses while driving. As you get older, your eyes become more sensitive to glare. Ordinary sunglasses or goggles are only suitable for wearing during the day, driving at night will seriously affect the vision (national standards stipulate that light transmittance of night driving glasses must be greater than75%). Although the all-weather driving glasses can weaken the strong lights, the vision darkens and affects road safety which does not meet the national standards for driving glasses at night. You should choose functional driving glasses that can block strong light, glare and increase the field of vision. This can effectively reduce the glare of the car lights but can filter out the extra harmful light. When worn at night, it can soften the strong lights and make the vision clearer. In this way, the safety of drivers is ensured, the fatigue of eyes is alleviated, and the radiation damage of harmful lights to glasses is prevented.