As we age, the lens, the focusing system of our eyes, begins to slowly harden and lose its elasticity, and its adjustment power begins to gradually weaken, leading to a normal physiological phenomenon: presbyopia. If the near point is greater than 30 centimeters, and objects cannot be seen clearly within 30 centimeters, and you need to zoom further away to see clearly, you should consider wearing presbyopic glasses.
This time we learn about progressive multifocal glasses in presbyopia optics. When presbyopia occurs, it is particularly tiring to see, because the human eye is in a relaxed state when looking far away, and macro-focusing is required when looking close. However, the adjustment power of the presbyopic lens is weak, and the focus is not strong enough when looking close, which will increase the burden on the eyes. , symptoms such as eye soreness, blurred vision, and headache are common symptoms.
The principle of progressive multifocal lenses
The design principle of multifocal lenses is to create numerous continuous far, intermediate and near visual focus points on one lens. Generally, the upper part of the lens is for far refractive power, the lower part is for near refractive power, and the center part of the lens is a gradient area that gradually exceeds refractive power. The near optical center of most multifocal lenses is 10-16 mm below the far optical center and 2-2.5 mm nasally. It should be noted that there are aberration areas on both sides of the progressive zone. When the line of sight moves to this area, the visual object will be deformed, making it difficult and uncomfortable to see.
How to use progressive multifocal lenses
Progressive multifocal lenses gradually increase power from top to bottom, and provide three hidden progressive lens areas, covering far, intermediate, and near vision, clearly conveying scenery at different distances. When you wear progressive multifocal glasses for the first time, the field of vision on both sides of the lenses may be skewed and distorted. When the frame position moves or becomes skewed, it may also cause discomfort and blurred vision. Follow the steps of "quiet first and then move, first inside and then outside" to gradually practice and adapt.
01. Telephoto lens area
When driving or looking, keep your chin slightly inward, keep your head horizontal, and look through the center of the lens slightly higher.
02. Mid-distance lens area
When driving or looking, keep your chin slightly inward, keep your head horizontal, and look through the center of the lens slightly higher. You can move your neck slightly up and down until the image is clear.
03. Close-up lens area
When reading a book or newspaper, place it directly in front of you, extend your chin slightly forward, and adjust your gaze downward to the appropriate mirror area.
04. Blurry mirror area
There are areas on both sides of the lens where the brightness changes, and the field of vision will be blurred. This is normal.
05. Suggestions:
Going up and down stairs: Lower your head slightly and look down, and adjust your sight from the near mirror area to the middle or long distance mirror area.
Daily walking: If you find it difficult to focus, try looking one meter ahead to adjust the focus. Please lower your head slightly when looking up close.
Driving or operating machinery: If you need to look from far to near, sideways or from multiple angles while operating, please do so only after you are completely accustomed to progressive lenses.
Post time: Dec-01-2023