We have been talking about the advantages of epithelium off cross linking. This from of cross linking has shown to work in numerous studies across the world.
But are all delivery methods the same? Certain machines hope the patient keeps looking at the UV light. Have you tried staring at something for 30 minutes. As a kid you may have played the stare off game. Its tough to do it especially in Los Angeles with the dry weather.
The solution in this fight against keratoconus is to involve a pupil tracker. In the above video you will see it in action. If the eye moves away form the light the UV delivery and the timer will stop. You can set how much movement you are willing to allow.
This increase the safety. One can definitely know that 30 minutes were delivered. It can avoid a situation where a fidgity patients moves and receives only 20 minutes of the radiation. Increasing safety also relaxes the patients. Most of people requiring this intervention against Keratoconus eye disease are teenagers. Pupil tracking rocks.
Epithelium off Cornea collagen cross linking is not voodoo. We realize that early in new technology lot of unfounded claims like api on cxl being Better than epi off might be made. It behooves us clinicians to present proof to peers.
There is a symbiosis between diagnostic technology and treatments. We will take help of Carl Zeiss Ocular coherence tomography to demonstrate the effectiveness of api off cxl.
Here is a High Density picture of a keratoconus cornea before any treatment. Yes it is early keratoconus in a young girl. This is the best time to intervene to treat Keratoconus. Look how uniform the picture is. The top layer of epithelium can be clearly seen. We remove this layer with laser or as Professor Theo Seiler recommends with ethyl alcohol.
Epithelium prevents riboflavin from entering the stroma and hinders the UV absorption. Look at the picture below. You can clearly see a haze which ends around 80 % depth as a line of demarcation.
The same line of demarcation after cornea cross linking is better highlighted in they colored OCT of the Cornea.
If you are suffering from Keratoconus Call 805-283-6520 to see if cross linking of cornea is the best option for you.
or Does it really work?
We pose this question as many medical Insurances deny patients reimbursement for cornea cross linking to treat keratoconus. Many parents also pose this question as their own optometrists were unaware of the benefits of cross linking the cornea.
We are going to turn to Australia for a peer review objective answer to this question. Our Australian colleagues performed a study which has been vetted by our peers. The Australian keratoconus experts selected 100 eyes with progressive keratoconus eye disease. They divided them into 2 groups. One would receive Conventional cornea cross linking while the other would have no intervention ( like your insurance company would want). They measured various data like vision, cornea thickness, and curvature of the cornea at various intervals over a period of 3 years.
Are you ready for the results? Can you guess what they showed?
Yes Conventional cross linking with UVA applied on riboflavin soaked eyes was able to prevent steepening of the cornea. It preserved vision both uncorrected and best corrected. It also improved the shape and vision in many instances. We are so convinced by the results we would not be bale to repeat it here in the United States. For we would not condemn any kid with keratoconus to be in the control group. The benefits are so obvious. Like society eradicated Polio it is time to wipe away keratoconus eye disease.
Feel Free to print the abstract from the respected Journal Ophthalmology which is attached as an image to show your doubting doc, illogical insurance rep or obstinate optometrist.
BMW on the autobahn is a hair rising experience. Now our German friends want to bring that concept to cxl or corneal cross linking. You may have heard of accelerated cornea cross linking? This is cxl with 10 minutes of UV radiation treatment, In the newest version they propose treatment of only 5 minutes utilizing 18 mw/cm2 of UV radiation.
This would of great benefit to patients. The amount of time they have to stare at the blue light would decrease. Exposure of the cornea to the elements would be less.
We would like to quote the results of the study here ” The mean follow-up time was 21.7 ± 7.2 months (range, 12-34 months). No statistically significant changes were found in the mean corrected distance visual acuity, corneal astigmatism, Kmean, Kflat, Ksteep, corneal pachymetry (at the apex and at the thinnest point), and corneal densitometry at follow-up. A significant reduction of Kmax, index of surface variance, index of vertical asymmetry, and Km of the posterior corneal surface (Km(B)) was observed (Kmax: P = 0.018; index of surface variance: P = 0.016; index of vertical asymmetry: P = 0.038; Km(B): P = 0.008). No complications were reported during the postoperative follow-up period in this study.”
Our question for the authors are. 1) How deep was the demarcation line?
2) was any comparison made to conventional cross linking?
Other papers or followup studies should be address the questions.
Dr.Khanna is a Keratoconus Expert. These informative blog posts are for information purposes. They should not replace a careful discussion with you Keratoconus Eye surgeon.
Keratoconus eye disease is no laughing matter. It afflicts teens and can destroy careers. We need to accelerate our fight against this vicious disease. At the same time we have to study scientifically the newer protocols. Accelerated cross linking speeds the treatment by decreasing the time of exposure of UV light. This has recently been studied in pediatric keratoconus.
This landmark study from Hong Kong By Surgeons of Royal college is a landmark one. It shows that accelerated cornea cross linking slows the progress of the bulging eye disease. it is the first one to document that only conventional cornea cross linking with its deep demarcation line can actually flatten the cornea. In essence it means that the 30 min api off intervention can halt the progression as well as reverse some of the effects.
The deeper the demarcation line the more the cornea flattening .
Keratoconus Experts in Los Angles thank the authors to bring new meaningful data for mutual benefit.
Accelerated Cross linking has been in use to treat Keratoconus. The traditional time of cross linking at 3 mw of UV energy has been 30 minutes. In accelerated protocols the energy is increased to 9 mw and the time decreased to 10 minutes. It is more comfortable for patients especially teens.
In this recently published study we find that accelerated cross linking is as effective as conventional cross linking. This is good news for Keratoconus Experts seeking to cure and halt the progression of the disease. The doctors of this study done at Zurich compared the results in patients where keratoconus had been documented by corneal topography. The corneal thickness had to be greater than 400 microns.
They compared the shape or topography and vision 12 months later. They found the accelerated treatment had similar outcomes.The failure rate in accelerated were 9/39 whereas in conventional they were 6/39.
So statistically accelerated crosslinking may be as good as conventional. Still it is not superior.