By Amy Hellem
Patients who have keratoconus and other corneal irregularities present unique challenges. To be sure: there is no cookie-cutter approach to fitting, nor is there one lens that will work for everyone.
However, specialty contact lens designs including the UltraHealthand UltraHealth FC are making it easier than ever to treat corneal irregularities such as keratoconus, pellucid marginal degeneration and corneal scars, as well as RK, Lasik and other forms of post-refractive surgery.
The following strategies have helped doctors achieve great success when fitting patients in these innovative hybrid designs.
Put Your Best Foot Forward
Make comfort and vision a priority.
“I very rarely will fit just a rigid gas permeable on a keratoconus patient at this point because I find that the centration and the comfort and the fit are so poor that the dropout rate is extremely high,” says Brian Brightman, OD.
Another lens option is a scleral. These lenses are easy to fit, but can be unpredictable in terms of long term vision and comfort. “A scleral lens will fit one way when you first look at it, it fits differently an hour later and then it fits differently eight hours after that,” says Dr. Brightman.
As a result, he instead advocates a comfortable hybrid such as UltraHealth as first-line therapy for irregular corneas. “[UltraHealth] is very comfortable from hour one, hour four, hour eight; and doesn’t change how it fits,” he concludes.
Set Up For Success with UltraHealth
With UltraHealth, start with the 250 vault flat skirt lens. From there, you’ll be able to determine the appropriate fit by increasing or decreasing vault in 100 micron increments to find first apical touch and order a lens with 100 microns of apical clearance. Although doctors may differ in how they choose to determine apical clearance and/or touch, the end goal is always the same, says Jeffrey Sonsino, OD. “An ideal UltraHealth fit is determined by vault over the apex of the cornea.”
With UltraHealth FC, start with the 255 Vault lens. When fitting UltraHealth FC, the first lens you select should be the 255 vault lens. From there, you’ll be able to determine the appropriate fit by increasing or decreasing vault in 100 micron increments to find first corneal touch under the vault area. Order the first lens 50-100 microns over first touch.
If there is heavy inner landing zone bearing, consider UltraHealth FC. UltraHealth FC and UltraHealth vaults 300 to 550 microns have a variable lift curve design that offer greater peripheral clearance than the UltraHealth vaults 50 to 250. If you observe heavy inner landing zone bearing in the lower vaults, consider switching to the UltraHealth FC design.
Over-refract to find the final lens power.
Once you have identified an ideal lens, over-refract to find your final lens power. Simply add the vertexed over-refraction to the power of the diagnostic lens that you have on the eye. Your over-refraction will be the same for each lens; however, this power is not interchangeable between UltraHealth and UltraHealth FC platforms.
Remind patients that fitting is a process.
Patients with significant corneal irregularities often need to be reminded that fitting is a process that takes time to perfect, but is worth it in the long run. Joe Vansuch, OD, finds it helpful to point out to patients how complex their particular cases are. He then offers his support by saying, “This is going to be a process … if you are willing to go down that mile, I am willing to go that extra mile with you.”
Amy Hellem is an independent writer and researcher who specializes in ophthalmology and optometry. Previously, she served as editor-in-chief of Review of Optometry and Review of Cornea & Contact Lenses and directed the custom publishing division for Review of Ophthalmology.