Pentacam: THE CENTREPIECE IN A SPECIALTY CONTACT LENS CLINIC

The iconic OCULUS Pentacam has found a home among specialty contact lens practitioners largely thanks to its advanced software for scleral contact lens fitting. The company has made significant upgrades to the technology, with Queensland optometrist TREVOR WILLIAMS one of Australia’s early adopters.

Orthokeratology (ortho-K) provided the gateway for Mr Trevor Williams’ interest in advanced contact lens fitting. The owner-optometrist of his namesake independent practice, in the Brisbane suburb of Coorparoo, enjoys the clinical satisfaction of improving patients’ lives through customised contact lenses, which brings the added benefit of differentiation.

With a service based on exceptional clinical care underpinned by investment in advanced diagnostic technology, two years ago Williams expanded his specialty contact lens offering by taking the plunge into scleral contact lenses for patients with keratoconus, post-LASIK ectasia and other conditions with abnormal corneas.

He had owned an advanced corneal topographer for some time, but to prescribe scleral lenses he required new hardware that could accurately map the anterior shape of the eye, across the cornea and all the way to the sclera, ensuring the lens can vault over the cornea.

To support his scleral lens service, he sought an earlier model of the OCULUS Pentacam – a German made, multifunctional anterior segment tomographer, supplied by Designs For Vision in Australia and New Zealand. Although popular among anterior segment ophthalmologists, it’s also found a home among specialty contact lens practitioners.

That’s largely because OCULUS developed an optional software module called the Cornea Scleral Profile (CSP) Report – originally available on the Pentacam and Pentacam HR models – to capture scleral topography in a non-invasive fashion. Together with sagittal height data and scleral angles, this is said to provide eyecare professionals with the necessary parameters for fitting scleral lenses.

The original CSP Report requires the practitioner to capture five scans – a central corneal scan and four scleral scans (inferior, superior, nasal, temporal) – which the software merges into one overall cornea and sclera map.

When he started using the software, Williams was impressed with its ability to create custom fit scleral contact lenses, often without the need for multiple trial fits. However, he noted some inefficiencies due to the need to stitch together multiple scans, and often he required assistance to keep the patient’s eye lids open.

But that all changed in a few months when Williams – an optometrist of more than 30 years – upgraded from the Pentacam Basic to the Pentacam AXL Wave and began using OCULUS’ upgraded software, CSP Pro. It provides more coverage in a single scan – up to 22mm diameter with a speculum – which is faster by avoiding the need to create a mosaic of the scans. Hence, it offers a better user experience and more reproducible data for the practitioner.

The software upgrade is available on OCULUS’ Pentacam AXL Wave, which became available in Australia in mid-2020. The fourth-generation system is the company’s most advanced Pentacam to date and is the first to combine Scheimpflug tomography with axial length, total wavefront, refraction and retroillumination.

Hearing the benefits CSP Pro could bring to his scleral lens fitting service, Williams made it a priority to have the Pentacam AXL Wave installed in his practice in September 2022, the first in Queensland.

“I’m now able to obtain much more efficient and accurate measurements of the cornea and sclera. With the CSP Pro it’s usually a case of one scan and you’re done, if the lids are wide enough apart or you use the speculum. But it still has the ability for you to stitch together multiple scans, if required,” he says.

“It’s nice and simple for the patient and myself – it’s been a welcome addition to the practice.”

With CSP Pro, Williams says he’s able to obtain high quality data that’s translating into accurate scleral lenses.

“Previously, there were times where it could take three or four lenses to get a good fit and a happy patient but now with the excellent elevation data from the CSP Pro software it’s usually done in one or two goes.”

Another impressive feature of the Pentacam and CSP software, according to Williams, is its ability to take measurements independent of the tear film.

“With my existing placido topographer, which is a great instrument, you must take several measurements to make sure the results are repeatable, due to the variability in the tear film quality between blinks. With the Pentacam AXL Wave, you are measuring the true corneal surface, not the tear film.”

“Unlike other scleral profilometers, fluorescein is not required to image the sclera. And because you’re able to work from a longer distance compared to a small cone topographer, it’s not so intimidating for children, while still being able to capture a wide scan.”

In terms of other features, the Pentacam data is capable of being exported directly to the contact lens laboratory’s design software and Williams hopes this will become more readily available in Australia in the future.

He also likes the simplicity of the display and readings. This makes it easy to interpret findings and educate patients on their conditions and the need to invest in scleral lenses.

“I show patients their cross-sectional scans to demonstrate the warped shape of their cornea. Advanced keratoconus patients, in particular, are often gobsmacked and then I can show them why a normal lens is not going to sit correctly, and why there’s the need for a large scleral lens to vault over their distorted cornea.”

Many Devices In One

As the owner-optometrist of an eyecare-led practice, the Pentacam AXL Wave is an example of how Williams carefully selects the latest diagnostic technology to provide a premium level of care.

Over the years he’s invested in the OCT, ultra-widefield retinal camera, visual fields system, corneal topographers, optical biometer, and an advanced dispensing measurement system.

With the Pentacam AXL Wave being the latest addition to the practice’s equipment armoury, Williams says it has superseded some other instrumentation, proving to be a key space saver in the clinic. It performs autorefraction, aberrometry, retroillumination of the crystalline lens or IOL, axial length, anterior and posterior corneal measurements and scleral profilometry.

But he’s discovered an unexpected benefit for his practice. Using both the retroillumination function together with tomography, he’s able to show patients their cataracts or posterior capsular opacification. It even gives a Pentacam Nuclear Sclerosis Score (PNS) and he’s able to demonstrate to patients their level of cataract.

“I’m routinely showing patients their PNS cataract grading score,” he says.

“It also performs axial length automatically which I use for myopia management. I also think it’s really important to exclude subtle keratoconus in potential ortho-K patients and the fact that the Pentacam measures the posterior cornea as well, you’ll pick up some keratoconics earlier than if you used a placido topographer.

“All in all, the Pentacam AXL Wave has been a great investment for my practice, and has brought about greater efficiencies and accuracy with my scleral lens fitting that I don’t think would be possible on any other device.”

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*95-100% of children expressed a preference for contact lenses over glasses at each visit over 36 months. †’How much do you like wearing your contact lenses?’ 87/97 (90%) Top box ‘I like contact lenses the best’ Subjective response at 60 months. ‡Compared to a single-vision, 1-day lens over a three-year period; rate of progression maintained out to 6 years. On average, there was no indication that accumulated treatment effect gained following 3 or 6 years of MiSight® 1 day wear was lost during a 12-month cessation study in children aged 8-15 at initiation of treatment. Instead, eye growth reverted to expected, age average myopic progression rates. References: 1. Sulley A et al. Wearer experience and subjective responses with dual focus compared to spherical, single vision soft contact lenses in children during a 3-year clinical trial. AAO 2019 Poster Presentation. 2. CooperVision® data on file, 2019. 3. Chamberlain P et al. A 3-year randomized clinical trial of MiSight® lenses for myopia control. Optom Vis Sci 2019;96:556–567. 4. Chamberlain P et al. Myopia Progression in Children wearing Dual-Focus Contact Lenses: 6-year findings. Optom Vis Sci 2020;97(E-abstract):200038. 5. Chamberlain P et al. Myopia progression on cessation of Dual-Focus contact lens wear: MiSight 1 day 7 year findings. Optom Vis Sci 2021;98:E-abstract 210049.

6. Hammond D et al. Myopia Control Treatment Gains are Retained after Termination of Dual-focus Contact Lens Wear with no Evidence of a Rebound Effect. Optom Vis Sci 2021;98:E-abstract 215130. For instructions for use refer to https://coopervision.net.au/patient-instruction. MiSight®, Brilliant Futures™ and CooperVision® are registered trademarks of the Cooper Companies, Inc. and its subsidiaries. EMVCOO0841 ©2022 CooperVision.