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Contact lens manufacturers wrong: Australian research

20/03/2018By Matthew Woodley
Researchers from the Brien Holden Vision Institute (BHVI) have disproved what they claim is a common assumption held by contact lens manufacturers – that reducing the inherent spherical aberrations (SA) of the eye will improve vision.

In addition to designs aimed at reducing inherent SA in single vision contact lenses, the researchers also found that inducing negative SA in single vision contact lenses did not result in visual gains in terms of visual acuity or subjective metrics.

“This is the first study to show that inducing negative SA, as done in many commercial single vision contact lenses, does not improve visual performance.”
Dr Cathleen Fedtke, study co-author

To confirm this, the team randomly selected non-presbyopic adult myopes aged 18–33 years to wear either a lens with minimal or no spherical aberration, or a commercial lens designed with negative SA, and then conducted visual acuity measures and binocular vision assessments.

Participants were also asked a variety of questions concerning vision quality (clarity and lack of ghosting for distance, intermediate, near, and driving vision in day and night-time), vision stability, overall vision satisfaction, and ocular comfort using a numerical rating scale for each category. After five days of wear, the same tests were conducted and the survey repeated.

The authors also discovered that power profiles of soft contact lenses with negative SA could induce measurable changes in peripheral refraction, including relative peripheral hyperopia, which study co-author Dr Cathleen Fedtke said could have a negative consequence on the myopia progression.

“This is the first study to show that inducing negative SA, as done in many commercial single vision contact lenses, does not improve visual performance,” she said.

“Given current clinical interest in the peripheral retina in relation to myopia, clinicians should be aware of the insignificant visual performance gains when fitting soft contact lenses of this design on young and progressing myopes.”

New head of R&D

BHVI has also announced a new head of research and development, with Dr Ravi Bakaraju taking on the role vacated by Dr Paul Erickson last year.

The appointment means Bakaraju will be responsible for operational leadership for the development of translational research and innovation platforms in the areas of contact lenses, spectacles, intraocular lenses and instrumentation. He will also contribute to the strategic direction of the department.

BHVI CEO Professor Kovin Naidoo said the appointment was a natural evolution for the organisation as it continued to pursue its translational research activities.

“Ravi is an outstanding researcher and leader, who is already making a mark as a scientist and directing projects delivering IP now being licensed to industry,” Naidoo said, adding, “He also has the support of a team who are among the leaders in the world in their areas.”

Bakaraju has authored numerous peer-reviewed articles in the areas of ophthalmic and visual optics, presented at major conferences, and serves as an anonymous referee for more than 10 ophthalmic and vision science peer-reviewed journals.

Image courtesy: Flickr | Andy Simmons

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