|Medmont Studio’s Composite Eye feature uses multiple images from the E300 Corneal Topographer to create a complete 100% corneal analysis.|
|The Visionix VX 120, set to be released in March, can project a “˜virtual’ fluorescein stain pattern based on the corneal topography and the included lens database.|
New modules aid in the precise configurations of contact lenses for keratoconus and other corneal disorders.
Corneal topographers allow practitioners to fit specialty contact lenses with confidence, efficiency, reduced chair time, and successful visual outcomes. Computerized topographers, on average, digitally measure close to 10,000 data points across the entire corneal surface to produce a color-coded elevation map showing both a qualitative and quantitative assessment of the corneal curvature.
Unlike their manual keratometry predecessors, which measured only the central 3mm of the cornea, digital topographers evaluate the corneal curvature from limbus to limbus, assisting practitioners in the determination of the axis and degree of irregular astigmatism, post-surgical corneal irregularities, corneal ectasia, corneal scarring, and corneal disorders such as keratoconus or pellucid marginal degeneration (PMD).
BETTER LENS DESIGN
Patients who suffer from corneal irregularities are best fit with specialty contact lenses designed with topography-aided analysis. In addition to the standard axial and tangential map displays, newer computerized corneal topographers can provide a vast array of novel features. They allow the practitioner to manipulate and assess lenses without the patient present in the office.
Additionally, corneal topographers allow eyecare professionals to determine the parameters, and predicted fluorescein pattern for an optimally fit lens without a slit lamp examination.
The latest corneal topography modules eliminate the need for insertion of multiple diagnostic lenses, significantly reducing chair time. With these modules, ECPs can build a theoretical contact lens and analyze the simulated fluorescein. However, they must consider the blink-induced movement and lid tension when determining the final lens selection, as these factors can cause unwanted displacement and decentering.
Most notably, these topography modules help to design reverse geometry ortho-k lenses, such as Paragon CRT lenses. Successful central corneal flattening can be evaluated on subsequent examinations to determine if the CRT lens is properly positioned.
Scleral lenses, which are increasingly used for fitting keratoconus and PMD, are also best designed with topography-aided modules. Determining the vault of the scleral lens is achieved by analyzing the sagittal depth at the 10mm corneal chord via data the newer topographers provide.
Once the proper assessment and digital manipulations are made for each specialty contact lens, the practitioner can electronically submit orders to the lab. With the practitioner’s consent, the lab can make further modifications to design the best fit contact lens. Thanks to corneal topography, specialty contact lenses are now being designed with higher accuracy and improved patient satisfaction.
Anar Maurya specializes in ocular disease, post-surgical management, and fitting specialty contact lenses at Woodhams Eye Clinic in Atlanta, GA.
WHERE TO FIND IT:
Medmont PTY Ltd, distributed by Precision Technology Services Ltd. •800-663-4248 •medmont.com
Paragon Vision Sciences •800-528-8279 •paragoncrt.com
Visionix, Inc. •800-292-7468 •visionix.com