Comprehensive Knowledge of Glasses Manufacturing and Glasses [Part 6]

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About reading glasses

What are reading glasses? Presbyopia is caused by the gradual loss of elasticity of the eye lens with age, which reduces the eye's accommodation power and leads to the phenomenon of not having clear vision at close range.

Presbyopic patients feel that they cannot see clearly at close range and often push books far away to read. As presbyopia worsens, even if the book is taken far away, it cannot be seen clearly. If you force yourself to read or do close work, you will experience symptoms of visual fatigue such as eye fatigue, eye pain, blurred handwriting and even headache.

Presbyopia can be corrected with the help of convex lenses (reading glasses). When making reading glasses, the first consideration should be wearing comfort, rather than one-sided pursuit of near vision clarity. The glasses should take into account the user's close work habits, the refractive state of both eyes and the accommodation power; pay attention to leaving appropriate accommodation reserves to prevent visual fatigue. For patients with refractive errors, the degree of the lenses used to correct the refractive errors should be based on the actual situation of each person, and the presbyopic lenses that should be worn should be given.

Don't buy reading glasses on the roadside. Recently, my neighbor aunt found that she could not see the smaller handwriting clearly, so she bought a pair of reading glasses at a street stall. Since she wore reading glasses, she felt dizzy and nauseous every time she finished reading. After checking at major hospitals, she was fine. Later, she was advised to go to an ophthalmology hospital for examination and found that it was because there was something wrong with the reading glasses she bought on the roadside. After examination, the lens degrees of the left and right eyes of this pair of reading glasses were 50 degrees and 75 degrees greater than her actual presbyopia, respectively. In this regard, middle-aged and elderly people are also warned that they must have an eye test before wearing reading glasses.

Presbyopia is an aging phenomenon of the human body. The degree of presbyopia is related to the specific situation of each person, such as age, personal habits, physical fitness, etc. Moreover, due to the increasing frequency of computer and television use, many middle-aged and elderly people have presbyopia in advance. Therefore, you need to be extra cautious when wearing reading glasses for the first time, because wearing inappropriate reading glasses will not only fail to correct presbyopia, but also cause various side effects.

Many middle-aged and elderly people not only have simple presbyopia, but also may have astigmatism and even other eye diseases. Therefore, you must go to a regular hospital for an examination and check for other eye diseases before wearing them. Reading glasses should be tailored to your individual situation, and finished glasses are only suitable for customers with the same degree of both eyes and no astigmatism, and the pupil distance of the finished glasses is fixed. Therefore, before wearing glasses, you must go to a regular ophthalmology hospital for optometry and pupil distance measurement to ensure the best visual effect after wearing them.

 

How to choose frames and lenses for myopia? What should be paid attention to when wearing glasses for high myopia?

Frame selection: A good pair of frames should be made of stable, safe, reliable, and skin-friendly materials, and should be light, strong, and non-deformed. Choose from the perspective of the practicality of the frame. Choose frames according to vision conditions and uses.

Wearing time

If the glasses are used for long-term wear, other conditions can be appropriately relaxed and lighter frames can be selected to reduce wearing fatigue. If the glasses are only worn when reading, watching TV, and other concentrated eye conditions, the frames can be selected completely according to personal needs.

Vision conditions

People with high myopia should not choose semi-frame and frameless frames, because the thicker lenses are not only unsightly but also easily damaged when paired with frameless frames. People with high astigmatism should not choose frameless frames, because the lenses paired with frameless frames will have the problem of astigmatism axis displacement after long-term use, which will cause the objects viewed to deform.

The geometric center distance of the frame is close to the pupil distance of the glasses

Since the geometric center distance of most frames is greater than the pupil distance of the human eye, in many cases the temporal edge of the lens is obviously thicker than the nasal edge, and the temporal edge of the lens is exactly the place that is most easily observed by outsiders. The thickness of the lens of myopia glasses is mainly reflected in the horizontal direction of the frame glasses, so it is necessary to choose a frame with a geometric center distance close to the pupil distance of the glasses. This not only makes the nose and temporal edges of the lens close, but also effectively reduces the thickness of the temporal edge of the lens and improves the appearance.

Choose according to face shape

Based on the shape and contour of the face, most people's faces can be divided into 7 basic shapes, namely round, oval, square, triangle with base below, triangle with base above, rectangle and rhombus.

Specific needs

If the purpose of fitting glasses is largely for the need to match the image and the occasions. At the same time, if the vision condition does not restrict the frame, you can choose according to your specific needs. People who often engage in large-scale physical activities and sports should choose frames made of plastic steel materials with more compact frames and better impact resistance to reduce the chance of glasses being damaged due to accidental falls.

People who are busy at work and often travel can choose frames made of memory materials to avoid deformation and damage caused by frequent wearing and removing, throwing and placing, or being broken or crushed due to improper placement when taking a train or plane.

Students wearing glasses

You need to have an eye test first. According to the degree of eye test and pupil distance, choose a suitable frame. Try to choose a lighter frame that does not put pressure on the bridge of the nose. Primary school students should try to choose full-frame glasses, which are safer and provide better protection for the lenses. Do not choose frameless glasses. The structure of frameless glasses is to fix the lenses with screws. If they are subjected to external force, the lenses are easy to break and may cause damage to the eyes. Primary school students often exercise. If they are not careful, it will be very unsafe if the glasses are damaged.

Elderly people wearing glasses

Reading glasses are a common item for many middle-aged and elderly people. It is the best "weapon" to deal with dizziness, but many people in life do not pay much attention to it. They just buy a pair of them at night market stalls or farmers' markets. , reading glasses cannot be worn casually. The reading glasses sold on the street stalls are not tailor-made according to the degree of presbyopia of people. The degrees of the left and right eyes are the same, and the pupil distance is fixed. However, many people with presbyopia have different degrees of left and right eyes, and there are problems such as astigmatism. It feels okay to wear them at the time, but it is easy to have a series of problems such as dizziness, sore eyes, and decreased vision after wearing them for a long time. At the same time, unclear vision is not necessarily presbyopia. The early symptoms of many eye diseases are very similar to presbyopia. If presbyopia symptoms occur, you must first check your vision and fundus examination with an optometrist.

Beware of complications of high myopia!

Generally, myopia will no longer develop after adulthood, and the degree will gradually stabilize. Those who continue to develop after the age of 25 are called progressive myopia. I have come into contact with many high-degree customers, and I really understand their inconvenience and pain. Surgical recovery is often not feasible. The higher the degree, the greater the risk. There is still a large number of high-degree patients who cannot undergo myopia surgery. You can consider lens implantation, preferably only one eye, to reduce the risk! Almost all high myopia eyes have an increase in the axial length of the eye and a significant thinning of the sclera at the posterior pole of the eyeball. The main pathological changes are atrophy and thinning of the retina and choroid, which worsen year by year. Therefore, many serious complications may occur, some of which may cause blindness. It is the sixth leading cause of blindness in my country. Its main complications include retinal detachment, cataracts, glaucoma, vitreous opacity, etc. Therefore, friends with high myopia should pay special attention to avoid severe head concussion and impact to reduce the possibility of retinal detachment, and have regular fundus examinations and vision tests every year! 

 

How to properly maintain the lenses

For myopic friends, the most troublesome thing is the maintenance of glasses, especially the lenses. If the lenses are infected with bacteria, it may cause inflammation of the eyes during the wearing process. If you find that the glasses are dirty, you should immediately maintain them. So how should you maintain the lenses?

First, clean the lenses. If you find that the lenses are dirty or dusty, do not wipe them with the corners of clothes, because ordinary fabrics will scratch the lenses. You can rinse them with clean water and then use a paper towel to absorb the water droplets. It is best to use professional lens care solution for cleaning.

Second, the placement and storage of lenses. It is best to put the lenses of the glasses facing up and put them in a cool place. If the lenses are placed facing down, the lenses will be scratched, and the lenses will be easily deformed under long-term high temperatures. Also be careful not to put the glasses together with corrosive items. If you do not wear them for a long time, you should wrap them with a glasses cloth and put them in a special glasses box. This is also to avoid scratches on the lenses.

Finally, when wearing glasses, whether they are contact lenses or framed ones, do not look directly at the sun as this will damage your eyes. Also, if there are scratches on the lenses, it is not recommended to wear them as this will reduce your vision.

 

About photochromic lenses

Who is not suitable to wear photochromic lenses

If people with high myopia wear photochromic glasses, their vision is poor, and the photochromic lenses will inevitably make it difficult to see things, and they are prone to visual fatigue. Therefore, such people should not wear photochromic glasses.

Myopia with astigmatism, and those with a corrected vision of less than 1.0 should not wear photochromic glasses. People with myopia and astigmatism must see things clearly under bright light. After wearing photochromic lenses, due to the dim light, the pupils will dilate accordingly, causing a narrow anterior chamber angle, resulting in poor drainage of aqueous humor, which can easily induce glaucoma over time.

People with cataracts, glaucoma and other diseases may worsen their condition if they wear photochromic lenses, so they should not wear photochromic glasses.

What are photochromic lenses?

Photochromic lenses are also called "photosensitive lenses". Because silver halide chemicals are added to the lenses, the originally transparent and colorless lenses will become colored lenses when exposed to strong light for protection, so they are suitable for both indoor and outdoor use.

Photochromic lenses are made of optical glass containing silver halide microcrystals. According to the principle of reversible reaction of light and color, they can quickly darken under sunlight and ultraviolet rays, completely absorb ultraviolet rays, and neutrally absorb visible light; when they return to the dark, they can quickly return to colorless and transparent.

Because the added silver halide and copper oxide have been integrated with the optical glass, photochromic glasses can change color repeatedly. Long-term use can not only protect the eyes from strong light stimulation, but also play a role in correcting vision.

Photochromic lenses are mainly used in open fields, snowy areas, and indoor workplaces with strong light sources to prevent damage to the eyes caused by sunlight, ultraviolet light, and glare.

In simple terms, under strong light, the silver halide inside changes to black silver particles when exposed to light.

Classification of photochromic lenses

When choosing photochromic glasses, the functional characteristics of the lenses, the purpose of the glasses, and personal requirements for color are mainly considered. Photochromic lenses can also be made to change to multiple colors, such as gray and brown.

1. Gray lenses: They can absorb infrared rays and 98% of ultraviolet rays. The biggest advantage of gray lenses is that the original color of the scenery will not be changed by the lenses, and the most satisfying thing is that it can effectively reduce the light intensity. Gray lenses can absorb any color spectrum evenly, so the scenery will only become darker, but there will be no obvious color difference, showing a real and natural feeling. It belongs to the neutral color system and is suitable for all people.

2. Pink lenses: This is a very common color. It can absorb 95% of ultraviolet rays. If it is used as glasses for vision correction, women who must wear it frequently should choose light red lenses, because light red lenses have better absorption function for ultraviolet rays and can reduce the overall light intensity, so the wearer will feel more comfortable

3. Light purple lenses: Like pink lenses, because of their relatively dark color, they are more popular among mature women.

4. Brown lenses: They can absorb 100% of ultraviolet rays. Brown lenses can filter out a lot of blue light, which can improve visual contrast and clarity, so they are very popular with wearers. Especially in severe air pollution or foggy conditions, the wearing effect is better. Generally, it can block the reflected light from smooth and bright surfaces, and the wearer can still see the subtle parts clearly, which is an ideal choice for drivers. For middle-aged and elderly people with high vision above 600 degrees, it can be given priority.

5. Light blue lenses: You can wear solar blue lenses when playing on the beach. Blue can effectively filter out the light blue reflected by the sea and the sky. You should avoid using blue lenses when driving, because it will make us unable to distinguish the color of traffic signals.

6. Green lenses: Green lenses can effectively absorb infrared light and 99% of ultraviolet rays like gray lenses. While absorbing light, it maximizes the amount of green light reaching the eyes, so it feels cool and comfortable, suitable for people with easily fatigued eyes.

7. Yellow lenses: It can absorb 100% of ultraviolet rays, and allow infrared rays and 83% of visible light to penetrate the lenses. The biggest feature of yellow lenses is that they absorb most of the blue light. Because when sunlight shines through the atmosphere, it is mainly expressed as blue light (this explains why the sky is blue). Yellow lenses absorb blue light and can make natural scenes clearer. Therefore, yellow lenses are often used as filters or used by hunters when hunting. Strictly speaking, this type of lens does not belong to sun lenses because it hardly reduces visible light, but in foggy and dusk hours, yellow lenses can increase contrast and provide more accurate vision, so they are also called night vision goggles. Some young people wear yellow lens "sunglasses" as decoration, which is a choice for patients with glaucoma and those who need to improve visual brightness.

With the needs of modern life, the role of colored glasses is no longer just to protect the eyes, it is also a work of art. A pair of suitable colored glasses, matched with suitable clothing, can set off a person's extraordinary temperament.

 

What to eat is good for our eyesight.

Eating more hard food is good for eyesight: eyesight is regulated by the lens, which is equivalent to the lens, according to the activity of the choroid tissue. If the facial muscles are not fully developed, it will affect the eyesight. With the appearance of food softening tendency, children's jaws are less and less developed. Due to the lack of proper exercise of teeth, the teeth are not arranged neatly and the upper and lower teeth are not in good occlusion. If you do not chew for a long time in your daily diet and living habits, the facial muscles will gradually weaken, and the adjustment function of the crystal body will not work well. Therefore, encouraging children to eat some hard food can strengthen the exercise of their jaws.

Protein: Lack of protein can easily fatigue the eyesight. Protein is the main component of cells. Children should take in enough protein, especially animal protein. Lean meat, poultry, animal offal, fish and shrimp, milk, eggs, beans, etc. contain protein.

Vitamin A: Foods containing vitamin A are also good for the eyes. When vitamin A is lacking, the eyes' ability to adapt to the dark environment is reduced, and in severe cases, they are prone to night blindness. Vitamin A can also prevent and treat dry eye disease. The best sources of vitamin A are livers of various animals, cod liver oil, milk and eggs, plant foods such as carrots, amaranth, spinach, leeks, green peppers, red sweet potatoes, and fruits such as oranges, apricots, and persimmons.

Vitamin C: It is one of the components of the lens of the eye. If you lack vitamin C, you are prone to cataracts with cloudy lenses. Various fresh vegetables and fruits, especially green peppers, cucumbers, cauliflower, Chinese cabbage, fresh dates, raw pears, oranges, etc. have the highest vitamin C content.

Rich calcium powder: It is also good for the eyes. Calcium has the effect of eliminating eye tension. For example, beans, green leafy vegetables, and shrimp skin are rich in calcium. Cooking methods such as roasted pork ribs soup and sweet and sour pork ribs can increase the absorption of calcium.

Vitamin B1: Vitamin B1 is one of the nutritional sources of the visual nerve. Insufficient vitamin B1 will cause eye fatigue; insufficient vitamin B2 will easily cause keratitis. Children with this problem can eat more sesame, soybeans, fresh milk, malt and other foods.Wolfberry: It has the effect of clearing the liver and improving eyesight, and is good for the eyes. Wolfberry is rich in carotene, vitamins A, B1, B2, C, calcium, iron, etc., and is a nutrient for the eyes.Bad eating habits can damage our eyesight, and correspondingly, choosing the right food can also help us maintain our eyesight. Do you remember it?

 

About astigmatism

Symptoms of astigmatism: Astigmatism is an abnormal refractive performance of the eye, which is related to the curvature of the cornea. Some people's corneas are more curved in a certain angle area, while other angle areas are flatter. The cause of astigmatism is that the uneven thickness of the cornea or the uneven curvature of the cornea makes the refractive rates of the corneal meridians inconsistent, so that the light passing through these meridians cannot be concentrated at the same focus, and the light cannot be accurately focused on the retina to form a clear image. This situation is called astigmatism.

See if you have astigmatism?

1. Blurred vision

Blurred vision is closely related to the degree and mode of astigmatism. People with mild astigmatism usually have normal vision, but they may experience headaches, eye fatigue and blurred vision when looking at objects at a certain distance. People with severe astigmatism have unclear and distorted vision. They can't see clearly at a distance or near. If they work at close range for a long time, their eyes will swell and have headaches, and they will read or have double images.

2. Visual fatigue

The blurred image on the retina requires constant fine adjustment, and the vision is distorted, so astigmatism, especially hyperopic astigmatism, is prone to visual fatigue. Young people with compound hyperopic astigmatism can often use adjustment to compensate, and according to the degree of adjustment, pseudo-simple hyperopic astigmatism, pseudo-simple myopic astigmatism or pseudo-compound myopic astigmatism can be formed.

3. Deviation from normal head and eye position

People with highly asymmetric astigmatism in both eyes often take a tilted head position to see more clearly, resulting in strabismus, which can be restored after astigmatism correction. People with high astigmatism often squint when looking at distant targets, achieving the effect of pinholes and slits to improve vision. Looking through pinholes or slits can reduce the impact of astigmatism on vision.

 

What causes eye pain?

What causes eye pain? Computer users are most likely to have eye pain. What causes eye pain? Excessive use of eyes, foreign objects in the eyes, and glaucoma can all cause eye pain. For computer users and white-collar workers, using computers is the most basic work skill, but this causes eye muscle fatigue. What should I do if my eyes hurt?

Eye pain and eye fatigue can be divided into accommodative eye fatigue, muscle eye fatigue, and neurological eye fatigue. The first two conditions may cause myopia, aggravated myopia, astigmatism, or presbyopia with different degrees in the left and right eyes. Secondly, eye pain may also be caused by staying up late and drinking a lot of alcohol, causing eye congestion and pain.

1. The simplest and most convenient method - cold compress, hot compress, artificial tears, eyewash, etc. Although this method is simple and convenient and suitable for office workers to use to improve the symptoms of eye pain, it takes some time to eliminate the pain.

2. Pain caused by dry eyes. It is best to apply a bag of crushed ice or ice cubes to the eyes for 5 minutes every 2 hours, or take out the contents of an egg just taken out of the refrigerator, and the remaining eggshell can be used to apply to the eyes. Alternatively, you can use artificial tears or shed tears to relieve dry eyes. However, artificial tears should not be used indiscriminately. The best way is to cry.

3. Press the eyeball to relieve eye pain. Close your eyes, touch the eyeball with the fingertips of the index, middle and ring fingers of both hands, press gently or rotate slowly and gently, but not too hard. 1-2 times a day, 20 seconds each time can relieve the symptoms of eye muscle fatigue and eye pain of computer users.

4. Massage the forehead. Eye pain often causes headaches, which is the case of eye pain reflected on the forehead. Therefore, use 3 fingers on each hand to massage from the center of the forehead to the temples on both sides in a circular motion, and press hard with the thumb, especially when you encounter pain, you should massage harder. This will make the eyes under the eyelids feel soothed. Do it twice a day, repeat 3-5 times each time.

 

Scholars from the University of Georgia in the United States remind people of the dangers of overdrawing their lives. They point out that overwork can lead to serious consequences and easily cause problems such as depression, fatigue, low mood and decreased immunity. So where is the fine line between completing work and being a workaholic? Russian media has listed 5 manifestations of overwork for you. If you have gradually become a workaholic, please pay attention to moderate rest and ensure your health.

1. Feeling guilty about vacation

If you think that time outside of work is wasted and you sigh for it, then you are "shot", which obviously proves that you are a workaholic. Research by German scholars also shows that those who take a full rest after work are much more efficient than those who don't rest.

2. Not having enough time to do the work originally planned

You may think that there is plenty of time during the day and you have time to do everything, but this is just an illusion. Scholars have shown that the longer people work, the less likely they are to complete their plans because they don't allocate time reasonably. And making a list can help change this situation. It is recommended that you develop the habit of making a list every morning and don't switch to another thing without completing the planned work.

3. Severe vision loss

Deteriorating vision is the first sign of overloaded work. Doing eye exercises, taking a walk during lunch break, and not working overtime after work are all practical ways to ensure good health.

4. Family members start to complain

Your wife complains that you missed dinner time, but you often ignore her complaints. But what if these complaints are correct? Have you completely forgotten that you still play the role of husband, father and pillar of the family?

5. Be the last one to leave work

If you are still working overtime after get off work, it means that you have not completed the tasks entrusted to you within 8 hours of work. This either means that your workload is really too heavy or that you are not using your working time effectively.

 

The above is some knowledge about glasses, including the materials of glasses, the advantages and disadvantages of glasses of various materials, the lenses of glasses, as well as knowledge of optometry and frame selection. I hope it will be helpful to you.