‘Brazen’ claims triggers curiosity about an old eye condition — presbyopia

A pharmaceutical company’s eye drops, developed to reduce dependency on reading glasses, have been mired in controversy ever since the company first said it had received approval from the Drug Controller General of India. A media report subsequently stated that claims about the approval and of the drops offering spectacular treatment for presbyopia were “unethical and false presentation of facts,” and the company has been asked for an explanation.
But through all of this, there has been renewed interest in presbyopia — what is it, and whom does it affect?

Presbyopia, states the Mayo Clinic’s website, is the gradual loss of your eyes’ ability to focus on nearby objects. It’s a natural part of aging. Presbyopia usually becomes noticeable in your early to mid-40s and continues to worsen until around age 65. 

The word ‘presbyopia’ comes from the Greek word ‘presbys’ meaning ‘old man’ and the New Latin ‘opia’ — essentially a condition that impacts older people. 

How do you know if you have presbyopia? You may find it hard to do tasks that require close-up focus, such as threading a needle. You may have blurred vision while reading. You may find that you have to hold books and other reading material further away to be able to read them. You may get headaches. If that is the case, going to the ophthalmologist for an eye exam can help confirm if you have presbyopia.

Why does presbyopia occur? Presbyopia occurs gradually. When you are young, the lens in your eye (behind your iris) has the ability to change shape — which means it allows you to focus on things that are both far away and close by. As you get older, this flexibility or elasticity of the lens decreases, and it becomes more rigid and is no longer able to change shape to focus on close-up objects, making them seem out of focus. There is no way to stop this ageing process, but it can be corrected, as is usually done with reading glasses.

How do reading glasses help? Reading glasses make up for the lack of elasticity in your lens by working like a magnifying glass – making it easier for your eyes to focus on the text. While they can be easily bought without a prescription, it is best to know what power of glasses you need, with an eye exam. 

“By the age of about 40,” says Mohan Rajan, chairman and medical director of Rajan Eye Care Hospital, “people may need +1 reading glasses. This power will gradually increase as they age: by about 45, you may need +1.5; by 50, you may need +2, and so on. This is a common and universal condition,” he said.

There are now multiple options when it comes to reading glasses: bifocals and even trifocals are available where the lenses are powered to focus on close-up work, middle distance vision and long-distance vision.

So where do the eye drops come in? A press release from the manufacturer, ENTOD Pharmaceuticals, states: “The proprietary formula not only gets rid of reading glasses but also helps the patient lubricate their eyes as a side benefit. These eye drops utilise advanced dynamic buffer technology to swiftly adapt to tear pH, ensuring consistent efficacy and safety for extended use, keeping in mind that such drops will be used for years at a stretch.”

However, doctors have urged caution: pilocarpine, which is an ingredient in the eye drops, works by constricting the pupil, they say and can have multiple side effects. 

“This is not a new drug – it has been used for decades in glaucoma treatment,” said S. Soundari, medical director, Dr. Agarwal’s Eye Hospital in Chennai. “However, now, there are other, better drugs available to treat glaucoma. Pilocarpine can have a number of side effects: it can cause headaches, it can blur the vision, it can hamper night vision since the pupil becomes smaller, and over the course of many years, this can cause problems with pupil dilation, which may be needed for instance, if the patient needs a cataract surgery. We also don’t know how effective the drops will be for all categories of presbyopia patients. So caution must be exercised,” Dr Soundari pointed out.

Dr. Rajan too highlighted potential side effects: “Constriction of the pupils can lead to eye muscles spasming. The drops are also not effective for very long periods – when their effect wears off, you may have to use them again. There are also other potential side effects that may occur, such as retinal detachment, cataracts and your field of vision becoming smaller,” he stressed.

It’s always advisable to treat fantastic claims about medicine with a large bag of salt, experts say. Also, when easier, safer, affordable therapeutic options are available, in this case, spectacles, it makes sense to stay safe, even as we wait for the technology behind the new options to be convincingly explained.
(zubeda.h@thehindu.co.in)

(With inputs from ANI)