Presbyopia is the age related loss of the ability to see up close. There are several options to surgically correct presbyopia, although some are still not yet approved by the FDA. A patient from Santa Barbara asked me recently about Presbyopia and what refractive surgery options are available now — and in the near future – for its correction.

Presbyopia is the age related loss of the ability to see up close. It generally starts in your early 40’s and gets progressively worse until about age 60. It happens because the lens inside your eye gets stiffer and stiffer with increasing age, making it less able to focus up close. Traditionally, the main correction for presbyopia has been a pair of over the counter reading glasses, or “cheaters.”

Today, there are several options for surgically correcting presbyopia. Some of these are very evolved and established, such as blended vision LASIK, and others have not yet been approved by the FDA, such as the KAMRA Accufocus corneal inlay. The following is a summary of the various surgical options for correcting presbyopia to help patients see up close with less need for reading glasses:

1) Multifocal Implants. These lens implants are put inside the eye after cataract surgery or refractive lens exchange. They sacrifice some contrast resolution and night vision quality in order to help patients see better up close. Some surgeons feel that multifocal lenses, while providing good close vision, can cause a 30% reduction in contrast resolution. In some cases, this can cause difficulty with low light and night vision driving and a pair of driving glasses often will not solve the problem. Some surgeons are concerned about the long term consequences of reducing contrast resolution in the eye as certain eye diseases of aging (such as macular degeneration) can add additional contrast loss with age to the optical system as the patient gets older. An example of a multifocal implant is the ReSTOR.

2) Accommodating Implants. These are lenses that are placed in the eye at the time of cataract surgery or refractive lens exchange that are designed to mimic the youthful human lens’ ability to flex to see near and far. In theory, these would be an excellent correction of presbyopia, but their downside is that there is nothing that comes close to replicating mother nature and making the person see like a 25 year old. The amount of accommodation so far has been a bit of a disappointment, although it can help some mid range vision. An example of an accommodating implant is the Crystalens.

3) Fluidic and Electronic Lenses. This is a peek into the future. These lenses would be implanted after cataract surgery or refractive lens exchange but they are not yet near FDA approval. The NuLens uses a piston activated by a muscle in the eye to push silicone gel into a small hole forming a bulging which focuses light for up close. =This design is based on the lens of a water fowl! Elenza is an even more complex lens for helping close vision. When it is stimulated for close vision, an electric current changes the orientation of liquid crystals to change the focusing of the lens. The electric signal is driven by micro-sensors placed in the eye that interpret that neurological impulses for seeing up close are being sent from the brain to the eye.

4) Full LASIK or PRK monovision. With full monovision, the dominant eye is set for distance and the near eye is set for close. This set up can allow for good distance and close vision, but it does have a downside as the two eyes tend not to work as a “team.” Contrast resolution suffers, as does night vision. A pair of glasses for night driving can help. Some patients tolerate the downsides of full monovision much better than others. We routinely simulate full monovision using lenses or contact lenses before LASIK surgery to see if it is a good idea for you. In general, while I find some patients benefit greatly from full monovision, many more prefer a milder degree of monovisoin called “blended” monvision (see below).

5) Blended monovision LASIK or PRK. Blended monovision essentially is a milder — and generally better tolerated — form of monovision than full monovision. WIth blended monovision LASIK or PRK, the dominant eye is set for distance, but the non-dominant eye is set for mid-range instead of close, allowing the two eyes to function as a team for most patients, unlike the case for full monovision. This makes the quality of the vision more natural while still providing good mid range vision. The goal of blended monovision is not to eliminate reading glasses, but to allow patients to use a cell phone or other hand held device, or write a check, all without reading glasses. For most patients, this is a better compromise than full monovision. I do quite a bit of blended monovision LASIK and PRK in my practice. There is a mild decrease in night vision, but it tends to be better tolerated than with full monovision and a thin pair of night time driving glasses can improve the night vision.

6) Excimer Laser Corneal Shaping. This technique is similar to LASIK or PRK, but the goal is to create a multifocal shape in the cornea to help see near and far. One version has been callsed PresbyLASIK. Two other examples are IntraCor and SupraCor. Regression of effect over time is a concern, but these are inherently safer approaches than putting lens implants inside the eye since they do not enter inside the eye at all — they merely work on the outside coat of the eye. As with multifocal implants, contrast resolution and night vision issues are areas of concern and these are not yet FDA approved procedures.

7) Corneal Inlays. These inlays are placed inside the cornea itself. The most popular one at this point is the Accufocus KAMRA which uses a pinhole-like ultrathin inlay that is placed inside the cornea. Early results are promising, but this procedure is not yet FDA approved. Other corneal inlays under study for presbyopia correction are the Rainbow and the Flexivue Microlens (Presbia).

8) Scleral Expansion. This technique is based on the notion that the lens get larger with age and it is this expansion of the lens in a fixed space that actually causes presbyopia. Small expanders are placed in the sclera, the white part of the eye, to expand the space around the lens to allow it to move more freely. Results and durability of results have been mixed and there are some concerns about potential complications. An example of scleral expansion is the use of Refocus technology.

9) Femtosecond Laser Lens Softening. Some experimental work has been done using a laser to soften the natural lens to make it more flexible. In theory, this could be a true cure for presbyopia. While flexibility can be improved in some cases,however, too many patients in studies have developed cataracts, so this is still a concept in its very early stages.

See Also

Presbyopia
All About Vision discussion of the causes and treatments of presbyopia.

Presbyopia (FDA)
FDA discussion of various treatments for presbyopia, including refractive lens exchange and clear lens extraction.

Surgical Reversal of Presbyopia FDA Monitored Clinical Trials
New York Eye and Ear Infirmary review of FDA clinical trials for surgical correction of presbyopia using the Refocus technology.

New Hope for Presbyopes
American Academy of Ophthalmology discussion of accommodating intraocular lenses to improve near and mid range vision.

Presbyopia
American Optometric Association review of presbyopia.

Monovision LASIK
American Academy of Opthalmology discussion of monovision and its use in LASIK for surgical correction of both near and distance vision.