Ophthalmologists need to remember value of contact lenses in practice

Recent advances in contact lens technology make them a necessary component of ophthalmology practices.

Contact lens technology has made great advances in recent years, allowing for more options and increased safety for the patient, according to one surgeon.

“A better knowledge of the pathophysiology and needs of the cornea has allowed us to develop better materials and better designs, so that we can now offer a wide range of options. Indications have widened and safety has greatly increased,” Florence Malet, MD, said in an interview with Ocular Surgery News at the meeting of the French Society of Ophthalmology in Paris.

More than 100 million people worldwide are currently contact lens wearers, and this number is likely to increase with the new models specifically designed for keratoconus patients, children and patients with presbyopia.

Keratoconus

Dr. Malet said that contact lenses are still the first treatment option for keratoconus.

“About 75% of patients are treated with contact lenses, and many of those who undergo surgery either with corneal graft or with intracorneal ring segment implantation also need them to optimize vision,” she said.

Today’s models and materials better adapt to the irregular shape of keratoconic corneas, put practically no pressure on the apex, and are stable and comfortable to wear.

Rigid gas permeable lenses are the first choice to treat keratoconic eyes. The new models available allow good tear film clearance and can therefore be kept in the eye all day long. They also come in a variety of shapes and diameters, to be specifically adapted to the various stages of the disease.

“As keratoconus progresses, you need an increasingly smaller diameter, a flattening in peripheral curvature and a narrower optical zone,” Dr. Malet explained.

In some cases, when patients complain of discomfort with rigid lenses, piggybacking can be an alternative.

“We maintain the geometry of RGP lenses, which is very specific for the keratoconic cornea, but an underlying soft lens is used to provide the comfort and to increase the stability of the rigid lens,” she explained.

Soft lenses are not a good option for keratoconus. To compensate for the irregularity of the keratoconic cornea and provide good visual acuity, these contact lenses need to be thick. Consequently, soft lenses do not allow enough oxygen to pass through, leading to complications.

Dr. Malet emphasized that a good contact lens specialist who provides the patient with the appropriate lens can avoid or at least postpone the need for surgery. She advocated for a closer collaboration between corneal surgeons and contact lens specialists.

“Many patients go directly to the surgeon because they say they cannot tolerate their lenses. And, in fact, they are right because the fitting is not good — the lens is too tight or not well calibrated for their refraction. In most cases all they need is a new lens with a different geometry to have both comfort and good vision,” she said.

In the cases in which intracorneal ring implantation is needed, the choice of an appropriate lens to wear after surgery is also crucial. Intracorneal rings flatten the cornea and allow patients to see better, but not optimally in all cases.

“We can fit these patients with a soft, frequent-replacement toric lens. By also addressing the astigmatic component, we can obtain very good results in terms of visual acuity,” Dr. Malet said.

For the old and the young

Contact lenses are now proposed as a solution for presbyopic patients. The design of the lens has changed, offering, through multifocality, the chance to see well at distance and near. The materials have also changed, often overcoming the tear film problems of contact lens wearers in this age group.

At the same time, the minimum age for safe use of contact lenses has considerably dropped.

RGP lenses are the first choice in keratoconus.

The alternative of piggybacking can be offered to patients intolerant to RGP lenses.

Infectious complications of contact lenses. Images: Malet F

“There are practically no limitations in terms of age. We can use contact lenses in children below the age of 6 for optical reasons, like high myopia, aphakia, anisometropia and nystagmus. After the age of 6 to 10, we can mix aesthetic and optic reasons. Contact lenses can be a powerful aid in correcting the deviation of the eye in cases of strabismus with esotropia. Children can wear contact lenses all day long and are much happier than wearing glasses,” Dr. Malet said.

RGP lenses are the first choice for children because they can be continuously kept in the eye for 7 days. The renewal of the tear film is 20 times higher than with soft contact lenses, and therefore all debris and pathogens are flushed away.

“They are extremely secure in terms of infectious complications. If even minimal problems of any kind arise, they are immediately perceived as pain or discomfort, which does not happen with soft lenses. So, they have a sort of inbuilt alarm. As soon as the child complains, they can be removed, and the eye will be safe,” she said.

Complication rate still high

Dr. Malet said that despite new technology with enhanced safety features, the rate of complications with contact lenses is not decreasing as expected.

“This is because contact lens wearers have not changed their habits,” she said.

Complications are due to misuse, insufficient lens care and not washing hands before inserting. In addition, many patients reuse daily disposable lenses and do not remove contact lenses soon enough once alarming symptoms arise.

“Patients tend to underestimate the risks of such behaviors and need to be well-instructed and constantly reminded of what they should and should not do,” she said.

Allergies and intolerance are due to the cumulative effects of preservatives contained in some soft lens solutions and not to the lens itself, so daily disposables solve the problem in such cases. Dr. Malet also said that due to the high oxygen transmissibility of the new soft materials, there are no more metabolic complications related to long-term use.

“These new materials allow five times more oxygen to go through the lens. It is a huge change that makes lifelong, prolonged daily use, up to 20 hours, comfortable and safe,” she said. – by Michela Cimberle

• Florence Malet, MD, can be reached at Hôpital Pellegrin, Place Amélie Raba-Lèon, 33076 Bordeaux, France; e-mail: florencemalet@free.fr.