keratometry

Top 10 questions about cross-linkingKeratoconus treatment has changed much over the past several years. Avedro’s U.S. Food and Drug Administration (FDA) approval of corneal cross-linking has given more patients hope for better vision.
How to improve IOL power calculations in keratoconusOne source of error in IOL power calculation is the use of the classical keratometric approach for the characterisation of the corneal optics. This approach is based on the assumption of only one corneal surface and a fictitious index of refraction (keratometric index, nk) for obtaining an estimation of the corneal power (Pk).
Bowman layer transplantation effective in advanced keratoconus
Bowman layer transplantation effective in advanced keratoconusIsolated Bowman layer transplantation can reduce and stabilize corneal ectasia in eyes with progressive advanced keratoconus, researchers said. “It flattens the cornea into a more normal position,” said Jack Parker, MD, a researcher at the Netherlands Institute for Innovative Ocular Surgery (NIIOS) in Rotterdam, The Netherlands. “It doesn’t give them perfect vision, but it keeps them from getting worse. It lets them to continue wearing their contact lenses.”
Learn how curiosity propels astigmatism innovationsPerhaps none so much as Graham D. Barrett, MD, a “pre-eminent expert in cataract and refractive surgery, and corneal and anterior segment disorders and surgery,” who was chosen to deliver the 2016 Charles D. Kelman Innovator Lecture at this year’s American Society of Cataract and Refractive Surgery meeting.
New approach to corneal power estimation in eyes with previous corneal refractive surgery and keratoconus eyesThe use of a keratometric index to estimate total corneal power calculation is imprecise, especially in corneas with keratoconus or after myopic laser refractive surgery. The errors can be reduced by using an adjusted keratometric index, consisting of a variable keratometric index that depends on the radius of the anterior corneal surface.
New study finds limits of keratometry in keratoconusReproducibility of keratometry is better for early keratoconus than for advanced keratoconus, a new study showed. The study could help clinicians decide when to use corneal cross-linking in their efforts to stop the progression of the disease, wrote Tom H. Flynn, PhD, and his colleagues from the Corneal Service, Moorfields Eye Hospital, St. George’s Hospital, London. They published their finding in the British Journal of Ophthalmology.
Digital marking system shows accuracy for toric IOL alignmentThough both ink marking and a newly introduced digital markerless system for toric IOL correction are effective, the digital system improved predictability and eliminated outliers in a comparison study.
Study finds hyperosmolarity of the ocular surface may impact cataract surgeryTearLab recently announced that preliminary results of the TearLab Cataract Study, which evaluated the relationship of a hyperosmolar tear film on keratometry readings.
Why keratometry is important
Why keratometry is importantKeratometry (K) is the measurement of the corneal curvature; corneal curvature determines the power of the cornea. Differences in power across the cornea (opposite meridians) results in astigmatism; therefore, keratometry measures astigmatism. It can be acquired with a variety of instruments either manually or via automated methods.