Contact lens update

Philadelphia-Tom Quinn, OD, FAAO, and Shalu Pal, OD, FAAO, discussed the contact lens market at the American Optometric Association’s Optometry’s Meeting.

“The driver for soft contact lenses is comfort,” says Dr. Quinn. “Manufacturers are doing a lot with edge design and posterior profile for improved comfort.”

Rates of microbial keratitis (MK) did not drop as hoped with the advent of silicone hydrogel (sihy) contact lens materials. Dr. Quinn speculates that perhaps there is higher binding of bacteria with these materials

Is a daily disposable sihy lens a good idea in terms of infection? Complication rates with daily disposable contact lenses is very low. Sihy lenses bring higher oxygen transmissibility and a slightly higher complication rate. The jury is still out on such a lens.

Next: Toric designs

Toric designs

Astigmatic fits are slowly growing, with 22 percent being fit in 2012 and 24 percent in 2013. This number is expected to increase, says Dr. Pal, likely due to greater ease of fit with toric lens designs.

Currently one in six Americans is astigmatic; however, only 40 percent of them wear contact lenses. Fitting astigmats is a big opportunity for these patients and eyecare practitioners.

“Likely no one has told these patients that newer toric designs are available,” says Dr. Pal. “We need to change patient perception.”

Daily disposable toric lenses are making a power push, according to Dr. Pal, with six options in the marketplace:

•1 Day Acuvue Moist (Johnson & Johnson Vision Care)

• clarity 1 day toric (Sauflon)

• ClearSight 1Day Toric (CooperVision)

• Dailies  AquaComfort Plus Toric (Alcon)

• Focus Dailies Toric (Alcon)

• SofLens 1 Day for Astigmatism (Bausch + Lomb)

If stability is a problem with a toric lens, look under the lid and at the cornea. The source of the problem might be the lid or the ocular surface, not the lens design, according to Dr. Pal.

With low astigmats, the question of masking the cylinder with a higher-modulus lens arises. Does this work? T

“The answer is for the patient to decide,” says Dr. Quinn.

Do higher modulus sihy lenses mask astigmatism?

Next: Multifocal designs

Multifocal designs

The contact lens dropout rate increases with presbyopia. The good news is that more than half who drop out will consider contact lenses again. Some 91 percent of contact lens wearers age 35-55 want to stay in lenses as they age, says Dr. Quinn.

“My favorite time to bring up multifocals is before patients need them,” says Tom Quinn. “So later when they develop symptoms, they know we can help them.”

Available multifocal daily disposables:

• clariti 1 day multifocal (Sauflon)

• Dailies Aqua Comfort Plus Multifocal (Alcon)

• Proclear 1 Day Multifocal (CooperVision)

Dr. Pal tells patients that they will have, on average, three visits for a final multifocal fit. Dr. Quinn says he doesn’t tell patients and prefers to leave it a mystery.

Hybrid multifocal designs offer good centration and flexure and are exclusive to eyecare professionals, says Dr. Quinn. “Address dry eye and lid disease before fitting hybrid lenses to avoid buildup and debris affecting the fit,” he says.

Next: Scleral lenses

Scleral lenses

Dr. Quinn recommends using inhalation saline in the bowl of the lens. This allows you to avoid putting a fluid chamber on the cornea.

He recommends that patients apply lenses using the elevator technique. The patient's face is parallel to the floor, and he then brings the lens up to the eye like an elevator.

“Look for corneal clearance,” says Dr. Quinn. “If the edge is touching centrally, it will affect everything else.”

The ideal corneal clearance is 250-350 µm at dispensing. The tear layer depth decreases by about 100 µm over 8 hours. Settling occurs most in the first four hours of lens wear, so schedule patients for follow-up after that time. Keep in mind that some patients have a spongier conjunctiva, which affects settling.ODT