Almost all of us experience presbyopia in middle age. You’ll know it’s happening when have to hold your favorite book, the daily newspaper, or a restaurant menu farther away just to read it. 

If the vision becomes blurry when looking at a phone or book but still appears clear in the distance, reading glasses may be helpful. But if you’ve always worn glasses, multifocal lenses may be helpful. Wearing progressive/bifocal lenses can simultaneously meet the visual needs of driving, computer, and mobile phone, avoiding frequent changes in glasses.

1. Bifocal and progressive lenses
2. Common side effects
3. How to adjust to bifocal and progressive lenses?

1. Bifocal and progressive lenses

Progressive lenses are suitable for dynamic eye use scenarios, such as office and daily life. Bifocal lenses are more suitable for static scenes such as reading and driving.

• Progressive lenses: There is no boundary line on the lens, and the degree gradually changes from top to bottom (far-middle-near). Its core principle is to achieve a smooth transition of degree through the continuous gradient of lens curvature, but there may be blurriness on both sides. In the initial stage of wearing, practice may be required, but once proficient, seamless switching of vision can be achieved.
• Bifocal lenses: divided into upper and lower areas, with a clear boundary between the upper and lower areas, allowing for a distant view and a closer view.

2. Common side effects

Although bifocal/progressive lenses can meet the needs of far, medium, and near vision simultaneously, there may be some side effects associated with early or even long-term use.

• 1. Dizziness or imbalance. When walking, the ground feels undulating, and it is easy to step on empty space when going up and down. This is due to the presence of blurred areas around the progressive and bifocal lenses, which the brain needs time to adapt to and actively ignore.
• 2. Blurred or distorted peripheral vision. The edge of an object is distorted or blurred when viewed from the corner, such as the rearview mirror being unclear while driving.
• 3. "Partially clear". The vision is divided into three parts, and the clear area becomes smaller. 
• 4. Unclear mid-range vision. When looking at the computer, you need to look up or down; otherwise the text will be blurry.
• 5. Driving at night will cause glare. When driving at night, the streetlights produce a halo, making the view on both sides even more blurry.  
• 6. Long adaptation. Some people need 1-2 weeks to adapt, a few need more than 1 month, and elderly people may take even longer.  

If the side effects of progressive lenses are unbearable, anti-fatigue lenses or bifocal lenses can be considered. Anti-fatigue lenses refer to low-degree progressive lenses (ADD+0.75~+1.25), suitable for people with mild presbyopia. And the bifocal lens abandons the adjustment of medium distance, making the switching between near and far more direct. 

3. How to adjust to bifocal and progressive lenses?

Adapting to bifocal or progressive lenses requires some time and skill, especially when worn for the first time. Here are some practical suggestions to help you adapt faster:

• 1. Persist in wearing it for at least 4 hours every day. The adaptation period usually takes 1-2 weeks or even longer, and intermittent wearing can prolong the adaptation time.
• 2. Avoid frequent replacement of old glasses. Unless you experience severe dizziness or nausea, try to continue using new glasses as much as possible.
• 3. Adjust eye habits to align the center of the screen with the distance zone of the lens. When looking into the distance, look up or slightly lift your head, and see the distance through the upper part of the lens. When looking at your phone or book, lower your head and use the lower part of the lens. When using a computer, adjust the screen height to align your gaze with the middle area of the lens.
• 4. Turning the head instead of turning the eyes. There are blind spots on both sides of the progressive/bifocal lens, so do not look sideways at objects next to you. Actively turn your head to avoid a sense of imbalance. When going up and down stairs, lower your head slightly to ensure that you can see the steps clearly through the lens's far end area.
• 5. Adapt in stages. Wear it in a safe and familiar environment to alleviate dizziness symptoms, and then gradually transition to outdoor or complex environments. Avoid prolonged walking or driving in the early stages until fully adapted.
• 6. For cases of blurred vision, lift the nose support of the frame to make it easier to align the “near” area with the line of sight.
• 7. When using progressive lenses, choose a style with a higher frame height to ensure sufficient proximity.
• 8. Dizziness/nausea symptoms usually subside within 1-3 days. If they persist for more than 1 week, it is necessary to check the optometry data or lens design for suitability.
• 9. For night glare, single-vision distance or reading lenses can be used.

Patience is key. Most people can eventually adapt to bifocal or progressive lenses and enjoy their convenience. If it is really difficult, other options can also be considered, such as two pairs of single-vision lenses or anti-fatigue lenses.