Presbyopia: definition, symptoms, and treatment

Degrees of presbyopia

The degree of presbyopia, measured in diopters (D), is typically age-related. On average, at age 45, it is about +1.5 D. It then increases linearly by approximately 0.5 D every five years, stabilizing at around +3 D by age 60.

How does a person with presbyopia see?

Loss of accommodation causes discomfort with near vision, requiring one to hold reading material at arm’s length or enlarge text on a computer or smartphone. The presbyopic patient must use a specific correction for near vision: glasses, multifocal contact lenses, magnifiers, etc.

Emmetropic patient (no distance vision defect) with presbyopia

Discomfort with near vision appears around age 45. After age 50, presbyopia progresses and also affects intermediate vision (such as computer screens). Distance vision is not affected and will not be impacted by the progression of presbyopia.

Myopic patient with presbyopia

Being myopic is akin to constantly looking through a magnifying glass. Distance vision is blurred, but near vision is clear. The myopic patient loses the ability to accommodate for near vision and experiences blurred near vision with their glasses. However, by removing their glasses, they benefit from their myopia, which compensates for presbyopia. Depending on the degree of myopia, the patient may be able to do without glasses for near vision.

Hyperopic patient with presbyopia

Loss of accommodation affects near vision and, eventually, distance vision as well. A mildly hyperopic patient (up to 2 diopters) may see well at a distance without glasses until age 40 by accommodating. After age 40, increasing difficulty with distance vision occurs due to the loss of accommodative ability associated with presbyopia.

Glasses and contact lenses

For many, wearing glasses or contact lenses is a simple and effective solution for managing presbyopia. However, regular monitoring is essential since presbyopia is a progressive condition.

Laser refractive surgery for presbyopia

Laser refractive surgery, initially reserved for treating other refractive errors (myopia, astigmatism, hyperopia), can now also treat presbyopia.

This involves reshaping the stroma, the intermediate layer of the cornea. Two distinct zones can be created: a central zone for near vision and a peripheral zone for distance vision. In other cases, each eye may be treated differently—one prioritized for near vision and the other for distance vision. The brain then merges the information from both eyes for normal vision.

The two main techniques are PresbyLASIK and PRK (Photorefractive Keratectomy). They differ in how the stroma is accessed and in the depth of corneal layers treated with the laser. The choice of technique depends on corneal characteristics, especially its thickness, and the patient’s activities. If there is a significant risk of ocular trauma, PRK is often preferred.

Implants

Various types of implants now offer additional options for managing presbyopia.

Phakic lens implants are inserted between the iris and the crystalline lens through a small incision. They then unfold inside the eye to provide the desired degree of correction.

Cataract surgery can also correct presbyopia, with the choice of implant depending on several factors, including any pre-existing refractive errors.

What about “magnifying” glasses for presbyopia?

Many people with presbyopia purchase over-the-counter “magnifying” glasses. At first glance, these seem advantageous: no need to see an ophthalmologist, inexpensive, easily replaceable, and no need for supplemental insurance. While these may be useful for short-term use, such as quickly checking a phone, prolonged use is strongly discouraged. The main reason is that both lenses are identical and correct both eyes in the same way, whereas it is rare for both eyes to have the same problem.

Prescription lenses, on the other hand, are custom-made to account for each eye’s specific needs. Their use prevents imbalance, which could otherwise lead to visual fatigue, headaches, and eye redness.

Is there a presbyopia eye drop?

In 2021, the FDA (Food and Drug Administration) in the United States approved the first eye drop aimed at improving vision in presbyopia.

These are Vuity drops, marketed by Allergan, with pilocarpine as the active ingredient. Pilocarpine, already known for use in glaucoma treatment, constricts the pupil. Daily administration of the drops, which are effective after about 15 minutes, can improve near (reading) or intermediate (computer work) vision for around six hours.

FDA approval was based on clinical trials involving 750 individuals aged 40 to 55. The main limitation is statistical, as the sample size is relatively small. Larger studies are needed to confirm the results.

Moreover, even if efficacy is confirmed, the effect is limited in duration, as the waking day is much longer than the six hours of action claimed by Allergan. The manufacturer also notes that only mild to moderate presbyopes can benefit, and advises caution when driving at night, as temporary difficulties focusing between near and distant objects may occur.

Finally, some side effects have already been reported: more than 5% of treated patients experienced headaches and eye redness.