Laird Harrison

May 07, 2017

LOS ANGELES — Electrical stimulation of the ciliary muscles can improve near and intermediate vision in people with early presbyopia, researchers say. However, at least one expert expressed doubt that the treatment would effectively treat the underlying problem.

The treatment could provide a less invasive alternative to refractive surgery, and theoretically might even delay cataracts, Luca Gualdi, MD, from the Studio Oculistico Gualdi in Rome, Italy, told Medscape Medical News.

"In the short term, we can say it's very effective in people with presbyopia, 40 to 50 years old, who don't already wear glasses," he said.

Dr Gualdi presented the finding here at the American Society of Cataract and Refractive Surgery (ASCRS) 2017 Annual Congress.

In presbyopia, the lens thickens and the ciliary muscles weaken with age, so that the muscles can no longer bend the lens to focus on near objects, Dr Gualdi explained. In people with near-vision glasses, the ciliary muscles "start to become more and more lazy."

To address the problem, Dr Gualdi and colleagues are experimenting with a contact lens connected by a cable to a generator. The device has received CE Marking.

The polycarbonate contact lens measures 20 mm in diameter and contains four 3-mm electrodes. The lens contacts the bulbar conjunctiva but does not touch the cornea, holding the electrodes at 3.5 mm from the limbus.

The device delivers compensated biphasic low-voltage current causing 2-second contractions interspersed with 6 seconds of rest.

In a recent trial, patients received oxybuprocaine 0.4% as a topical anesthetic. "The patient can feel a small tingling effect on the lids, but [it is] not painful," said Dr Gualdi.

In the current study, Dr Gualdi and colleagues applied the treatment to 49 emmetropic and early presbyopic patients with a mean age of 46.4 years. The patients had a maximum spherical equivalent for near vision of +1.25.

The researchers excluded patients who had epilepsy, pacemakers, pseudophakic or ocular pathologies, neuropathy, demyelinating pathologies, or vascular diseases.

Patients received four treatments in 2 months, followed by a maintenance dose every 3 months.

The researchers tested the patients under identical light conditions and at the same time of day every 15 days for 9 months.

By the second treatment, the researchers were able to document statistically significant improvements in visual acuity and reading speed (P < .05).

Table. Ciliary Electrostimulation Outcomes

  Visual Acuity: Reading Distance 40 cm. (LogMAR) Visual Acuity: Reading Distance 70 cm (LogMAR) Reading Speed MNRead Charts (Seconds)
Baseline 0.14 0.24 219.5
Second Treatment 0.06 0.16 190.88

Ultrasound biomicroscopy taken under accommodation showed an average increased lens thickness of +0.10 mm, a decreased anterior ray of curvature of −0.20 mm, and a decreased posterior ray of curvature of −0.08 mm. Accommodative amplitude also improved in the Duane test.

"Contrast sensitivity was better, and people could read more in dim light," Dr Gualdi said.

Although passive, the technique achieves some of the effect for ciliary muscles a gym workout achieves for larger muscles, he said.

If maintained, the treatments might stop the progression of presbyopia, and even slow the development of cataracts by keeping the lens in motion, he said. But he cautioned that "we need long-term results to say this."

In the discussion that followed his presentation, panelist Daniel H. Chang, MD, from Empire Eye and Laser Center in Bakersfield, California, asked how quickly the eyes regress if they do not receive maintenance treatments. Regression can begin within 4 months, and may be complete in 6 to 9 months, Dr Gualdi said.

Session moderator Thomas Kohnen, MD, PhD, from the University of Frankfurt in Germany, told Medscape Medical News he was skeptical this could prove an effective treatment for presbyopia.

Weakness in the ciliary muscles is not the main cause of presbyopia, he said. "The problem is that the lens is the thing which doesn't work anymore."

Possibly the electrostimulation could prove useful for some aspect of diagnosis, he added.

Dr Gualdi has disclosed no relevant financial relationships. Dr Kohnen disclosed financial interest in multiple ophthalmic companies.

American Society of Cataract and Refractive Surgery (ASCRS) 2017 Annual Congress. Presented May 6, 2017.

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