All of us Vs Keratoconus

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Post Info TOPIC: Why you should NEVER have Crosslinking or TPRK done.

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Posts: 46
Date: Thu May 11 8:40 PM, 2017
Why you should NEVER have Crosslinking or TPRK done.

ScottP, I think both our perceptions of "most commonly used" is heavily influenced by the comparatively few eye care professionals (ECPs) that we have experience with. I haven't pursued scleral lenses so I really have no idea of what type of scleral lenses ECPs in Southern California are fitting. I did look at the Europa lens and I agree that it seems like another step forward in KC lens design. I think the sMap3D from Precision Optical Metrology that Visionary Optics is promoting along with the Europa lens is even more interesting.

But there is only one company, Visionary Optics, that supplies the Europa lens. ECPs that use Visionary Optics as their scleral lens provider probably are migrating to the Europa design. But ECPs that do not already use Visionary Optics probably are sticking with whatever they know and use now. My guess is that I would have to make a lot of phone calls to find someone in Southern California with experience in fitting the Europa lens for a KC patient.

The problem with all KC lens designs is that each one requires the ECP to have experience with the particular design to be able to fit it effectively. Most (all?) lens designs require the ECP to purchase a fitting set to even begin trying to fit the lens. When you factor in that the incidence of KC is supposedly something like 1 in 2,000 patients, an ECP who works 250 days/year (a hard working ECP!) would have to do 8 new lens fittings per day to encounter even 1 KC fitting in a year. Even if we factor in some concentration of KC patients by directing them to specialists in fitting medically necessary contact lenses, I think it would be an exceptional ECP who sees more than 50 KC patients a year for an initial contact lens fitting. Trying to develop expertise in KC fitting for more than a few lens designs when you see so few KC patients is a challenge. And trying to justify technology like sMap3D for the number of scleral lens fittings that I would guess most ECPs do would be hard. It took a long time before corneal topography became widely used. And even now it is not universal. I am not sure the problem of providing the available range of KC contact lens designs to a significant number of KC patients is one that can be solved.

I am intrigued by the inability to fit Europa on your right eye because of lenticular astigmatism, which I understand to be astigmatism due to an issue with your crystalline (internal to the eye) lens. My understanding is that a ballasted scleral lens could be fit with the usual tear film correction of the irregular KC corneal surface and a toric front surface added to correct the lenticular astigmatism. This seems like it would work even better if sMap3D was used because apparently most sclera are toric and the outside edge on the back of the Europa can be matched to the sclera which stabilizes rotation of the lens without the need for ballast. Is my understanding of what's possible wrong?

In any event, I think Dr. Gemoules at LaserFit probably has the most advanced technique for fitting a scleral lens for KC. Using wavefront technology to determine the optical aberrations that need to be corrected by the lens is a giant leap in designing the refractive aspect of the lens. It is unfortunate that no one seems to have any interest in adopting the techniques that Dr. Gemoules has developed. But again, the realities of developing this kind of expertise and justifying the cost of the specialized equipment needed set in. Good luck with LaserFit! I look forward to hearing your experiences.

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