Presbyopia: The ever-changing environment and elusive Holy Grail

An expert panel of physicians discussed the various choices that eyecare professionals must make to manage presbyopia, with special emphasis on the emerging miotics for presbyopia.

The panel included S. Barry Eiden, OD, FAAO, president and medical director of North Suburban Vision Consultants and Eyecare Specialties of Illinois in Deerfield, Illinois; Francis Mah, MD, FAAO, FNAP, director of the cornea service and codirector of the refractive surgery service at Scripps Clinicin La Jolla, California; and Andrew Morgenstern, OD, AAO, FNAP, a subject matter expert for Walter Reed National Military Medical Center in Bethesda, Maryland.

All agreed on the huge toll of presbyopia.

Generally, Mah said, presbyopia affects individuals more today because of the extensive use of digital devices in daily activities. Patients express a great deal of disability navigating through their daily social/work activities.

An array of presbyopia treatments is available to ODs and MDs, including reading glasses, bifocals, multifocal contact lenses for monovision, LASIK, PRK, clear lens extractions, phakic intraocular lenses, and miotic drops.

The Holy Grail

Despite those options, Eiden said, the Holy Grail of presbyopia treatment remains elusive.

Mah mentioned that the optimal presbyopia treatment must satisfy a demanding audience and offer an excellent range of vision, durability, and mitigation of adverse effects associated with treatments, such as the inability of the brain to adapt to monovision and the surgical complications.

Pinpointing the cause of presbyopia

What actually happens in the eye with aging remains controversial.

Mah explained that the primary theory—the Helmholtz theory—says that with aging, the lens slowly loses its flexibility, which becomes noticeable at approximately aged 40 to 50 years.

“The other theory is that the lens stiffens and enlarges; although the ciliary body contracts and relaxes and the lens still has some flexibility, it’s too large for the ciliary body to move sufficiently to achieve slight accommodation,” Mah explained.

The role of miotic eye drops

Miotics cause pupil constriction, resulting in a change in pupil size, Morgenstern explained. Because of this change, light behaves differently, ie, it no longer acts as a big wave.

“The light beams act in parallel, and they have essentially an infinite focal point and don’t blur,” he said.

This pinhole optic is what causes the eye to see better at near.

However, adverse effects may occur, including spasms of the ciliary body that cause a beneficial myopic shift but also headaches or brow aches. In addition, the tension that the ciliary body causes can result in posterior vitreous detachment, retinal tears, or retinal detachment. The goal with development of miotics is to eliminate these adverse effects, Mah noted.

To hit the perfect target, Morgenstern discussed the need to constrict the pupil sufficiently to achieve the highest-quality near vision possible, thus optimizing the optical pathway. A size less than 2 mm is where the magic happens.

Thus far, Eiden pointed out, no commercially available drugs achieve the 2-mm optimal pupil size.

“Their efficacy is limited because of the ciliary body effect and the potential for other complications,” he said.

Available miotics

Pilocarpine 1.25%was the first to receive FDA approval; another pilocarpine drops 1% is in the pipeline with possible approval within the next 1 to 2 years, according to Eiden.

Carbachol, rimonidine, or a combination, strong miotics that affect the ciliary body and cause pupillary miosis, are in the works, Eiden said.

Mah noted that another drug, aceclidine, affects only the pupil sphincter and not the ciliary body and that aceclidine seems to be a step in the right direction because it has a longer-lasting effect (10 hours) than the available options. In addition, the hope is that there is significantly less vitreous pull and, therefore, fewer retinal detachments from retinal tears.

Recommendations for patients

With the various treatments available, the panelists suggested presenting a menu of options that complement each other. Patient and physician education are important to obtain the best outcomes.

Mah noted that by the time patients complain to him about their near vision, they have already tried glasses. He sees his examination as a great opportunity to positively affect their quality of life because of the treatment options available, albeit imperfect, to address presbyopia.

With refractive surgery, the patient chooses distance vision or monovision. In this scenario, a miotic agent to address presbyopia may be an adjunct to refractive surgery without compromising vision with monovision.

Morgenstern agreed that as an optometrist, it is important to inform patients about the multifocal options for cataract surgery. A daily disposable contact or a miotic drop may be an option.

“Optometry has so much technology—great drugs, drops, spectacles, and contact lenses,” he said. “We can pair these things together for our patients to optimize their vision. In some cases, a miotic drop can useful. Optometrists have the opportunity to talk about these options with patients.”

Morgenstern said that he begins by communicating with his patients to ascertain their visual preferences based on lifestyle and needs.

“As a team, we make the best decision,” he said.

Mah highlighted the importance of physician education.

“All this innovation is phenomenal and overwhelming,” he noted. “As a surgeon, I must educate myself about medications, contact lenses, and glasses, even though I don’t dispense them. Primary eyecare specialists also must educate themselves on all the options for cataract surgery.”

Eiden concluded that “in this ever-changing environment, it is incumbent on us as eyecare professionals to keep up...and educate our patients.”