In two of my previous posts, we defined presbyopia – that universal and annoying (to say the least) phenomenon of increasing difficulty with reading and near vision as we age. As I previously explained, presbyopia occurs because the natural human lens gradually thickens and becomes less flexible as we age, making it harder to change focus from distant to near objects.
I also went through some of the basic ways that we can treat or cope with presbyopia, namely reading glasses, bifocals, monovision contact lenses, and multifocal contact lenses.
Some of the above are fine options for patients who don’t mind wearing glasses or contacts, but what about patients who cannot tolerate contact lenses or simply don’t want the hassle of wearing reading glasses?
Are there any other ways to treat presbyopia besides wearing glasses or contact lenses?
Researchers have been working on an answer to this question for many years, even decades. This year, we finally saw FDA approval for the first primary surgical implant to treat presbyopia – the Kamra (Acufocus, Irvine, CA) corneal implant. The Kamra is a small, flat ring with a tiny pinhole-like opening. The inlay can be surgically implanted in one eye and can significantly increase the depth of focus in the treated eye, without decreasing the distance vision in that eye. Currently, there are three other similar products going through FDA trials, all of which may soon be approved for use in the U.S.
This technology is unique, because it represents the first successful way that we can improve near vision – without decreasing or compromising distance vision – through a surgical procedure. The goal of corneal implants like the Kamra is to make it so the patient does not need to rely heavily on reading glasses or contact lenses for near vision. This is very new technology, but it is likely that these inlays will gain significant popularity over the next few years.
What about treating presbyopia at the time of cataract surgery?
Although the new corneal implants can provide a primary surgical treatment for presbyopia, ophthalmologists have been finding ways to surgically treat presbyopia in combination with cataract surgery for many years.
To review briefly: cataract surgery involves removing a patient’s cataract – which is the natural clens that has become cloudy with age – from inside the eye and replacing it with a clear artificial lens. Our technology has advanced over the years so that we can choose a lens implant power that potentially can allow the patient to have better vision – even better vision without glasses – than they had with the cataract. For some patients, having cataract surgery can be a once in a lifetime opportunity to significantly improve both near and distance vision.
Here are the ways we can treat presbyopia at the time of cataract surgery:
Multifocal lens implants
Multifocal intraocular lenses can be implanted at the time of cataract surgery. Similar in design to multifocal contact lenses, multifocal IOLs have concentric rings of increasing power, splitting the light that enters the eye to provide improved clarity of vision at both distance and near. These lenses are ideal for certain patients who wish to decrease their need for reading glasses or bifocals after cataract surgery. Due to the rings, many patients see some haloes around lights with these lenses, but this phenomenon causes significant problems in less than 5% of patients. Patients with significant astigmatism will need to have this corrected with a laser astigmatic correction at the time of surgery in order for this lens to work properly.
The most commonly used multifocal lenses in the U.S. are the ReSTOR and the Technis multifocal lenses. To learn more about these premium lenses, you can follow the links below to the respective manufacturers’ websites:
It is important to note that multifocal lenses are not a guarantee of spectacle independence, but rather a lifestyle choice to decrease the need for prescription or reading glasses after cataract surgery.
Accommodating Lens Implants
There is another type of lens designed to have a moving hinge to simulate the natural changes to the lens that occur with accommodation. This lens, know by the brand name Crystalens, hinges slightly inside the eye to allow some near vision in addition to excellent quality distance vision. Patients who chose this lens may have some functional intermediate and near vision, but may need reading glasses to read fine print.
To learn more about this type of premium lens, you can follow the link below to the manufacturer’s website:
It is important to note that accommodating lenses are not a guarantee of spectacle independence, but rather a lifestyle choice to decrease the need for prescription or reading glasses after cataract surgery.
Monovision is the practice of correcting the patient’s dominant eye for maximum clarity at distance and correcting the non-dominant eye for improved near vision. Just as monovision can be achieved with soft contact lenses, it can also be achieved by placing appropriately chosen intraocular lenses at the time of cataract surgery – this can be done with either a monofocal, toric lens, or Crystalens, depending on the specific needs of the patient. Some individuals, however, do not tolerate monovision well because of a difference in focal distance bewteen the two eyes.
This concludes our three-part discussion on presbyopia and the many ways, surgical and non-surgical, we can treat this problem. As always, if you have questions or comments, feel free to post them or to contact me, Dr. Geoffrey Hill, directly by email at firstname.lastname@example.org