The revolution in vision care

June 1, 2010

Technology influencing vision care is advancing rapidly.

"Patients are more educated than in the past and expect that the doctors they see are up-to-date with technology and have the knowledge to provide answers to their eye-care questions," said Dr. Karpecki, clinical director, cornea services and ocular disease research, Koffler Vision Group, Lexington, KY.

Point-of-care diagnostics

Results of a clinical study comparing the performance of the osmolarity measurement device with other conventional assessments of dry eye disease-including Schirmer testing, tear film breakup time, and ocular surface staining-showed the superiority of the new technology for identifying patients with mild, moderate, and severe disease, Dr. Karpecki said.

"Point-of-care diagnostics allow the doctor to instantly acquire objective information that can be used in treatment decisions" he added. "These new devices are used for diagnosing ocular conditions, but in the future we are also likely to see instrumentation that can detect extraocular diseases or non-ocular or systemic diseases, such as diabetes or Parkinson's disease, based on tear markers."

In the area of diagnosing refractive error, alternatives to phoropters are being developed that offer an advantage for more precise measurement. One such device (VMax SR, VMax Technology) uses a point spread function target.

"We know some people will have 20/20 Snellen VA and yet do not have good quality vision," Dr. Karpecki said. "Refraction based on point spread function allows determination of optimal refraction with 0.01 D of accuracy, and we can expect this technology to be translated into spectacle manufacturing as well in the near future."

Developments in lens optics

Revolutionary developments are also occurring in the area of lens optics. One such technology involves the use of electro-active optics (Electronic Lens Technology, Pixel Optics) that provide active focus so that lens power changes almost instantly when the patient changes gaze for near or distant vision.

The spectacle lenses are designed with a thin layer of liquid crystal sandwiched between two layers of transparent electrodes. Microelectronic controls integrated in the temple of the spectacles detect changes in head position and transmit power to the electrodes that alters the molecular pattern of the liquid crystal, changing the index of refraction, wavefront curvature, and ultimately lens power.

"The frames are at least as attractive as popular frame styles, and weigh about the same because the microelectronic control system is so small," Dr. Karpecki said.

Drug delivery devices

The development of novel drug delivery devices has also been an area of active research in eye care. A drug-eluting contact lens containing ketotifen is in development for use in patients who are contact lens-intolerant due to allergies.

In addition, punctal plugs able to release a drug over a period of years are being tested as a delivery device for IOP-lowering medications; and sustained-release transcleral devices based on microneedles and nanoparticles are being looked at as an alternative to direct intravitreal injection for the management of diseases, such as chronic CME, cytomegalovirus infection, and posterior uveitis.

Corneal collagen crosslinking holds exciting promise for the treatment of keratoconus. The technique involves topical application of riboflavin drops to a de-epithelialized cornea followed by 30 minutes of exposure to UVA light. To date, clinical trial results have shown this treatment was consistently effective for halting disease progression.