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Today’s antireflective coatings improve upon earlier technology
Contact Lenses and Eyewear
Once considered problematic for their challenges of durability and cleaning, today’s antireflective coatings have addressed these issues with new topcoat materials, better surface applications and improved emulsion.
“Difficulty in cleaning was the number one problem, and scratching — or what we term ‘durability’ — was number two,” Nick Mileti, president of the AR Council, said in an interview. “But there have been a lot of changes in the industry as far as new technology, just in the past 3 or 4 years, that have significantly changed the product.”
Yorktown, Va.-based practitioner William Waldron, OD, said he considers current AR coatings to be vastly improved and would recommend them to almost any patient.
“There are patients who will tend to shy away from AR because of the previous problems with cleaning the lenses,” Dr. Waldron told Primary Care Optometry News. “But the new multilayer AR coats work much better, and they are so much easier to keep clean. They are cosmetically better, and, functionally, the vision is better. Everyone wants that in a pair of glasses.”
Improvements in topcoat technology
According to Mr. Mileti, the ease-of-cleaning issue has been dealt with through the development of enhanced “topcoats” containing hydrophobic and oleophobic properties.
“Manufacturers have been able to increase the so-called ‘wetting angle,’ and that means fewer items stick to the surface,” he said. “If a ball was going to come in contact with a flat surface, you would see where the underside of the ball is for the flat surface, as the wetting angle decreases. That ball sort of flattens over the surface.”
The newer hydrophobic coatings are able to increase the angle so that there is less water touching the surface of the lens.
The very smooth surface of AR did not do well when it came into contact with body oil, Mr. Mileti said. The oil had a tendency to smear across the lens, and additional cleaning time was required to remove the smear. However, today’s new topcoats have made significant improvements in that category with the addition of oleophobic properties, said Mr. Mileti. “Together, these newly enhanced properties in topcoats create less smearing, and the product is much easier to clean,” he said.
Improvements in longevity
Another recent development in topcoats has been the improvement of longevity. “The earlier topcoats really did a great job. However, the longevity wasn’t great,” Mr. Mileti said. “They were good for about 9 months to a year, and then they would wear off. It was a slow process, but the patient would eventually realize that the lens didn’t clean as well as it used to.”
Mr. Mileti said the longevity of today’s topcoats is much better, with some companies introducing new technologies within the past 5 months. “It is really phenomenal what they can do with these topcoats,” he said. “One company claims you don’t even need to use water to clean its product. You can use your tie.”
Improvements in static
Another improvement in AR technology is the creation of a “reverse ion charge,” reducing static to the lens, Mr. Mileti said. “There is some unique work being done with the layers of the coatings,” he said. “Industry-wide, the premium coatings today will have much better ease of cleaning, less static and less dust that accumulates on the lens. It is a vast improvement over the lenses of as little as 3 years ago.”
Charles McCormick, MD, president of the Indiana Academy of Ophthalmology, also commented on improvements in the layers of coatings. “When they first came out, there were only a few coats, and now they are not just multicoated, but electrostatically applied,” he said. “It is generally just a better surface application and a much better emulsion.”
Improvements in education
Equally important is the increased level of awareness and education disseminated by eye care practitioners to potential AR coating patients.
“There is much better education going on,” Mr. Mileti said. “Eye care professionals are teaching patients how to clean and care for the lenses. It has helped a great deal.”
AR for high index, high correction
Several factors should be considered when trying to determine whether a patient will benefit from AR coating. However, certain conditions are almost always helped by this coating, practitioners claim.
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“It is valuable in many lens implant patients and many early cataract patients,” Dr. McCormick said. “Invariably, these people with early cataracts complain of night vision glare, and I find that AR coating is very effective in limiting that.”
According to James Kershaw, OD, a practitioner in North Olmsted, Ohio, AR coating is beneficial for most prescriptions. “I think AR will benefit different patients for different reasons, and not all of the benefits are prescription-related,” he said. “That being said, certainly as you get into higher prescriptions, you are going to get into higher-index materials. And as you get into higher-index materials, AR coating will have a little more value.”
Dr. Kershaw emphasized that he considers this benefit to be more index-related than prescription-related. “However, even low prescriptions can benefit from AR coating,” he said. “And certainly the cosmetic benefits would be especially helpful to patients with higher prescriptions.”
Dr. Kershaw added that, to a certain extent, there is a personality profile for those patients most suited to AR coating. “The analogy is to look at lenses like food: some people will eat anything and be happy with it, while some people are more finicky,” he said. “It depends on the individual patient.”
Low-light benefit
Low-level lighting is a key benefit provided by AR coating, Dr. Kershaw said. “Patients who need good vision in low-level lighting, people in fields where eye contact is very important and patients who are finicky about the way they look would benefit most from AR coating,” he said. “As a practitioner, you need to go through the features and benefits and make sure the patient understands and is willing to pay the additional dollars for AR coating.”
Mr. Mileti said he has recently seen indications that the patient perception toward AR coating is improving. “We’ve been seeing, based on the feedback from our members, high repurchase rates,” he said. “That is an indicator of satisfaction.”
He said the two primary objectives of AR are to reduce reflections and to improve light transmittance.
“There have been a lot of changes in the industry in terms of new technology, just in the past 3 to 4 years,” he said. “These technologies have significantly changed the product. We think patients will find they don’t have to deal with the same unpleasant effects they experienced in the past.”
For Your Information:
- Nick Mileti is president of the AR Council. He can be reached at 2417 West 105th Street, Bloomington, MN 55431; (877) 254-4477; fax: (952) 881-4857.
- William Waldron, OD, can be reached at 1215-V George Washington Hwy., Yorktown, VA 23693; (757) 596-5666; fax: (757) 596-9755.
- Charles McCormick, MD, can be reached at 30 N. Emerson, Greenwood, IN 46143; (317) 881-3937; fax: (317)-887-4008.
- James Kershaw, OD, can be reached at 26777 Lorain Road, North Olmsted, OH 44070; (440) 734-4777; fax: (440) 734-0555.