What is presbyopia
Presbyopia is a normal condition in which your eyes gradually become less able to focus on nearby objects as you get older. Presbyopia is often referred to as the aging eye condition. Presbyopia is due to an age-related loss of lens accommodation that results in an inability to focus at near distances and is the cause of universal near vision impairment with advancing age. People often notice changes in their near vision around the age of 40. Usually, you notice that reading and focusing on objects close-up becomes more difficult, although you will still see distant objects clearly. Presbyopia is a natural part of ageing occurring in the adult eye and is normally corrected with the use of glasses or contact lenses.
Presbyopia usually worsens until around the age of 65. Presbyopia is a natural part of ageing and there is no known way to avoid it.
The strain of focusing your eyes might give you headaches and eye strain and you hold objects progressively further away from your eyes in order to be able to focus on them. You may become aware of presbyopia when you start holding books and newspapers at arm’s length to be able to read them. However, while objects may then be in focus, they may become too small to be identified. The length of your arm also limits this compensatory mechanism. The most common remedy is the prescription of a pair of reading spectacles or contact lenses.
- Note: Claims that certain eye exercises, therapeutic contact lenses, or medications can be used to treat presbyopia are false.
As presbyopia is a continual process, your prescription reading spectacles or contact lenses is likely to change significantly between the ages of 45 and 65. It is recommended that you have an eye test every 2 to 3 years. Vision changes of presbyopia will climax (need for maximum correction) by approximately age 63–65.
There is nothing that can be done to prevent the natural process of presbyopia. Ensuring that you have good, bright, and well-focused light and holding reading material farther away when you read is often very helpful. Good self-care also includes regular eye-care checkups, not only to preserve and protect your eyes but to detect whether you are getting presbyopia.
Those with perfect eyesight that develop presbyopia can often use reading glasses found in drugstores. These are very simple magnification lenses, usually with powers from +1 to +4 diopters (a measure of lens power). If this applies to you, take some reading material with you and test out the various glasses to find the one that works best for you. For a best test, hold the material at your normal (usually 14 inches away) reading distance. Note that a different power is needed for use with the computer.
Who’s at risk of presbyopia?
Anyone aged 40 and beyond will experience presbyopia. The timing of presbyopia is dependant upon the underlying requirement for vision correction. Meaning, if you are normally nearsighted (myopia) and wear corrective lenses for this, you might not be aware of difficulty with presbyopia until later in life (i.e., late 40s or early 50s). However, if you are normally farsighted (hyperopia or hypermetropia), you may experience presbyopia even before age 40. Certain general medical conditions, such as diabetes and high blood pressure, can affect the course and degree of presbyopia.
Can I have presbyopia and another type of refractive error at the same time?
Yes. It is common to have presbyopia and another type of refractive error at the same time. There are several other types of refractive errors: myopia (nearsightedness), hyperopia (farsightedness), and astigmatism.
An individual may have one type of refractive error in one eye and a different type of refractive error in the other.
What is refraction?
Refraction is the bending of light as it passes through one object to another. Vision occurs when light rays are bent (refracted) by the cornea and lens. The light is then focused directly on the retina, which is a light-sensitive tissue at the back of the eye. The retina converts the light-rays into messages that are sent through the optic nerve to the brain. The brain interprets these messages into the images we see.
To form an image, your eye relies on the cornea and the lens to focus the light reflected from objects. The closer the object, the more the lens flexes.
- The cornea is the clear, dome-shaped front surface of your eye.
- The lens is a clear structure about the size and shape of an M&M’s candy.
- Both of these structures bend (refract) light entering your eye to focus the image on the retina, located on the inside back wall of your eye.
The lens, unlike the cornea, is somewhat flexible and can change shape with the help of a circular muscle that surrounds it. When you look at something at a distance, the circular muscle relaxes. When you look at something nearby, the muscle constricts, allowing the relatively elastic lens to curve and change its focusing power.
Figure 1. Human eye
Figure 2. Eye anatomy
Figure 3. Presbyopia
As you get older, the lens in your eye becomes harder and less flexible. As your lens becomes less flexible, it can no longer change shape to focus on close-up images. Aging also affects muscle fibers around the lens making it harder for the eye to focus on up close objects. The ineffective lens causes light to focus behind the retina, causing poor vision for objects that are up close. As a result, these images appear out of focus. This makes it harder for you to focus on close objects.
When you are younger, the lens of the eye is soft and flexible, allowing the tiny muscles inside the eye to easily reshape the lens to focus on close and distant objects.
Everyone experiences some loss of focusing power for near objects as they age, but some will notice this more than others. People often notice changes in their near vision around the age of 40.
You might find it harder to focus to read, especially in poor light. You might also find yourself holding your book further away from you, or needing a brighter light for detailed work such as doing a crossword or crafts.
The strain of focusing your eyes might also give you headaches.
Presbyopia usually worsens until around the age of 65. It is a natural part of ageing and there is no known way to avoid it.
Risk factors for presbyopia
Certain factors can make you more likely to develop presbyopia, including:
- Age. Age is the greatest risk factor for presbyopia. Almost everyone experiences some degree of presbyopia after age 40.
- Medical conditions. Being farsighted (hyperopia or hypermetropia) or having certain diseases — such as diabetes, multiple sclerosis or cardiovascular diseases — can increase your risk of premature presbyopia, which is presbyopia in people younger than 40.
- Drugs. Certain drugs are associated with premature presbyopic symptoms, including antidepressants, antihistamines and diuretics.
Presbyopia develops gradually. You may first notice these signs and symptoms after age 40:
- Hard time reading small print
- A tendency to hold reading material farther away to make the letters clearer
- Blurred vision at normal reading distance
- Eyestrain or headaches after reading or doing close-up work
- Difficulty with needlepoint, crochet, or near-vision–requiring hobbies.
- Difficulty seeing text on the computer screen.
- Reduced contrast and clarity of reading material.
- The need for brighter and more direct lighting for reading.
- Fatigue, headache, or eyestrain – or all 3 – when reading or using the computer.
You may notice these symptoms are worse if you are tired or are in an area with dim lighting.
If you experience any of these symptoms you may want to visit an eye care professional for a comprehensive dilated eye examination. If you wear glasses or contact lenses and still have these issues, a new prescription might be needed.
Your optometrist or ophthalmologist will assess your eye in a comprehensive examination. If you already wear glasses or contact lenses, they will be able to tell you if you need a new prescription.
As presbyopia is a continual process, your prescription is likely to change significantly between the ages of 45 and 65. It is recommended that you have an eye test every 2 to 3 years.
Presbyopia is diagnosed by a basic eye exam, which includes a refraction assessment and an eye health exam.
A refraction assessment determines if you have nearsightedness or farsightedness, astigmatism, or presbyopia. Your doctor may use various instruments and ask you to look through several lenses to test your distance and close-up vision.
Your eye doctor likely will put drops in your eyes to dilate your pupils for the eye health exam. This may make your eyes more light sensitive for a few hours after the exam. Dilation enables your doctor to more easily view the inside of your eyes.
The American Academy of Ophthalmology recommends that adults have a complete eye exam every:
- Five to 10 years under age 40
- Two to four years between ages 40 and 54
- One to three years between ages 55 and 64
- One to two years beginning at age 65
You may need more-frequent exams if you have risk factors for eye disease or you need glasses or contact lenses.
The goal of treatment is to compensate for the inability of your eyes to focus on nearby objects. Presbyopia is usually corrected with the use of glasses (spectacle lenses) and sometimes with contact lenses. Other treatment options include undergoing refractive surgery, or getting lens implants for presbyopia. Many people begin with simple reading glasses, but prescription bifocals, multifocals and more specialized lenses are also available.
Eyeglasses are the simplest and safest means of correcting presbyopia. Wearing glasses to correct presbyopia doesn’t change how quickly the condition develops and will not weaken your eyes.
A few surgical techniques are also available to improve the eyesight of people with presbyopia, but they cannot be reversed and are not totally effective over long periods of time. If you are considering surgery, discuss it first with your doctor and your ophthalmologist.
Eyeglasses are a simple, safe way to correct vision problems caused by presbyopia. You may be able to use over-the-counter (nonprescription) reading glasses if you had good, uncorrected vision before developing presbyopia. Ask your eye doctor if nonprescription glasses are OK for you.
Most nonprescription reading glasses range in power from +1.00 diopter (D) to +3.00 D. When selecting reading glasses:
- Try different powers until you find the magnification that allows you to read comfortably, starting with the lower powers
- Test each pair on reading material held at a comfortable distance
You’ll need prescription lenses for presbyopia if over-the-counter glasses are inadequate or if you already require prescription corrective lenses for nearsightedness, farsightedness or astigmatism. Your choices include:
- Prescription reading glasses. If you have no other vision problems, you can use glasses with prescription lenses for reading only. You will need to remove these when you’re not reading.
- Bifocals. These lenses have a visible horizontal line that separates your distance prescription, above the line, and your reading prescription, below the line.
- Trifocals. These glasses have corrections for close-up work, middle distance vision — such as for computer screens — and distance vision. Trifocals come with two visible horizontal lines in the lenses.
- Progressive multifocals. This type of lens has no visible horizontal lines, but has multiple powers for distance, middle distance and close-up corrections. Different areas of the lens have different focusing strengths.
- Office progressives. These lenses have corrections for computer-distance and close work. You generally use these at a computer or for reading and remove them for driving or walking around.
Contacts for presbyopia
People who don’t want to wear eyeglasses often try contact lenses to improve their vision problems caused by presbyopia. This option may not work for you if you have certain conditions related to your eyelids, tear ducts or the surfaces of your eyes such as dry eye.
Several contact lens types are available:
- Bifocal contact lenses. Bifocal contact lenses provide distance and close-up correction on each contact. In one type of bifocal lens, the bottom, reading portion of the lens is weighted to keep the lens correctly positioned on your eye. Newer types of bifocal contact lenses offer one type of correction through the edges (periphery) of each lens and the other type of correction through the center of the lenses.
- Monovision contact lenses. With monovision contacts, you wear a contact lens for distance vision in one eye (usually your dominant eye) and a contact lens for close-up vision in the other eye.
- Modified monovision. With this option, you wear a bifocal or multifocal contact lens in one eye and a contact lens set for distance in the other (usually your dominant eye). You use both eyes for distance and one eye for reading.
Refractive surgery changes the shape of your cornea. For presbyopia, this treatment can be used to improve close-up vision in your nondominant eye. It’s like wearing monovision contact lenses. Even after surgery, you may need to use eyeglasses for close-up work.
Talk with your doctor about the possible side effects, as this procedure is not reversible. You might want to try monovision contact lenses for a while before you commit to surgery.
Refractive surgical procedures include:
- Conductive keratoplasty. This procedure uses radiofrequency energy to apply heat to tiny spots around the cornea. The heat causes the edge of the cornea to shrink slightly, increasing its curve (steepness) and focusing ability. The results of conductive keratoplasty are variable and may not be long lasting.
- Laser-assisted in situ keratomileusis (LASIK). With this procedure, your eye surgeon makes a thin, hinged flap deeper into your cornea. He or she then uses a laser to remove inner layers of your cornea to steepen its domed shape. Recovery from LASIK surgery is usually more rapid and less painful than other corneal surgeries.
- Laser-assisted subepithelial keratectomy (LASEK). The surgeon creates an ultra-thin flap only in the cornea’s outer protective cover (epithelium). He or she then uses a laser to reshape the cornea’s outer layers, steepening its curve, and then replaces the epithelium.
- Photorefractive keratectomy (PRK). This procedure is similar to LASEK, except the surgeon completely removes the epithelium, then uses the laser to reshape the cornea. The epithelium is not replaced, but will grow back naturally, conforming to your cornea’s new shape.
Intraocular lens implants
Some ophthalmologists use a procedure in which they remove the lens in each eye and replace it with a synthetic lens. This is called an intraocular lens.
Several types of lens implants are available for correcting presbyopia. Some allow your eye to see things both near and at a distance. Some change position or shape within the eye (accommodative lens). But lens implants can cause a decrease in the quality of your near vision, and you may still need reading glasses.
Possible side effects include glare and blurring. In addition, this surgery carries with it the same risks as those associated with cataract surgery, such as inflammation, infection, bleeding and glaucoma.
Some people have had success with a presbyopia treatment that involves inserting a small plastic ring with a central opening, into the cornea of one eye. The opening acts like a pinhole camera and allows in focused light so that you can see close objects.
If you don’t like the results of your corneal inlay procedure, your eye surgeon can remove the rings, leaving you free to consider other treatment options.
You can’t prevent presbyopia. You can help protect your eyes and your vision by following these tips:
- Have your eyes checked. Do this regularly even if you see well.
- Control chronic health conditions. Certain conditions, such as diabetes and high blood pressure, can affect your vision if you don’t receive proper treatment.
- Protect your eyes from the sun. Wear glasses or sunglasses that block ultraviolet (UV) radiation. This is especially important if you spend long hours in the sun or are taking a prescription medication that increases your sensitivity to UV radiation.
- Prevent eye injuries. Wear protective eyewear when doing certain things, such as playing sports, mowing the lawn, or painting or using other products with toxic fumes. Nonprescription reading glasses generally don’t provide safety protection.
- Eat healthy foods. Try to eat plenty of fruits, leafy greens and other vegetables. These foods generally contain high levels of antioxidants as well as vitamin A and beta carotene. They’re also vital to maintaining healthy vision.
- Use the right glasses. The right glasses optimize your vision. Having regular exams will ensure that your eyeglass prescription is correct.
- Use good lighting. Turn up or add light for better vision.
- See your doctor immediately if you experience any of these symptoms — sudden loss of vision in one eye with or without pain, sudden hazy or blurred vision, double vision, or see flashes of light, black spots or halos around lights. Any of these symptoms may signal a serious medical or eye condition.