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Today, our interviewer is talking to our ophthalmologist and clinical investigator Dr. Kirstin Deuble-Bente about the ophthalmological clinical research we do at SGS proderm.

Kirstin Deuble-Bente

Head of Clinical Investigations

Kirstin, you have been a regular investigator with proderm not only in ophthalmological studies for close to 20 years now. But of course, as you are involved in most of the eye studies at proderm, the most obvious question is: What are you actually testing in these studies?

In the medical field we conduct clinical trials with medical devices and medicinal products in ophthalmological indications like for example dry eye syndrome. In our consumer care branch we are mostly testing the ocular tolerability of cosmetics that are applied around the eyes, for example creams, shampoos or make-up removers. Consumer care products can easily get into the eyes, either because you just have it on your fingers when you rub your eyes or simply by accident. What happens if the product causes eye irritation? Customers tend to avoid products that are not well tolerated.

I can imagine! What are the most exciting studies to you?

I always love when a product surprises me! In our work with ocular tolerance testing, we apply a lot of products that are intended for skin care around the eyes directly to the eye - we have done studies where we instilled cream into the eyes and people had perceived such a great moistening of the eye that I suggested considering the cream for use as a treatment for dry eyes!

Is there any sort of study that you were not able to do until now, that you would be excited about?

I would love to do a glaucoma study at some point! One other type of study I would find very exciting would be about ocular symptoms of allergies. It is allergy season right now and you can feel it - Just last Friday, which is my practice day, I had eight emergencies of people coming in with allergic conjunctivitis, so it would actually be quite interesting to test different anti-allergic eye drops, perhaps in combination with anti-allergic tablets, etc. Somehow this kind of study hasn't come up yet, but we would be well equipped for it!

So, sponsors have an interest in making sure their products don't irritate the eyes, but how do you judge eye Irritation?

Yes, so you always do a basic examination of course. I look at the eyelids, the different types of conjunctiva, the sclera and cornea, which is quite sensitive. We also assess the strength of the tear flow.
When we do eye instillation studies, we apply the product directly into the eye, and then we assess what happens – Does the conjunctiva change? The bulbar conjunctiva practically changes after a few seconds to minutes. It reacts relatively quickly. The conjunctiva in the lower eyelid needs a bit more time and what is quite fatal for a product is when the so-called scleral vessels are visually detected after some time.

So basically, when the subject's eyes turn red?

No, the eyes turn red with any reaction to a product. If the deep vessels turn red, which can only be evaluated by a trained ophthalmologist, it indicates a very strong reaction, meaning the product has already failed.

What about tears? I presume you get tears no matter what you instill into the eye?

Well, first off, you have the natural tear film of the eye anyway. When you instill some aqueous solution into your eyes, you naturally have a little liquid in your eye, but it quickly disappears after a few blinks. Then, if the eye reacts, actual lacrimal liquid will appear; in the next stage, the liquid forms a tear, then the tear will run down and then finally there is a massive tear flow.

Are there any products where tears are not desired?

Absolutely! Some products, such as shampoos, like to claim that they are "no tears" and we often conduct studies to support this claim for our sponsors.

How would you set up such a study?

Well, we compare the test products to a well-known baby shampoo brand which is proven to be very mild and has a very low tear inducing potential. And the product needs to perform as good as or better than the reference product.

Interesting! And you judge this visually?

Yes, with the slit lamp! My most important tool!

Let's show some other assessments we can do - What other equipment do we have available?

So, we do have a device to measure intra-ocular pressure. For future studies we want to get a smaller, more modern version - it's already on my wish list! 

And apart from the slit lamp and the tonometer, what other devices could we use in eye studies?

Well, recently we tested a device called a meibometer. We have different glands in our eyes, producing different components of the tear film, so to speak. The so-called meibomian glands produce a lipid component to the tear film, and dry eyes are often associated with low meibomian gland activity. The meibometer measures the amount and composition of these lipids in the tear film by taking a tear film sample from the eye with a type of sample strip that can be inserted into the instrument for analysis.

What's a break-up time measurement?

Well, that's another assessment that we do using the slit lamp which is to determine the break-up-time of the natural tear film. Tear-up time is used in practice to determine if someone is suffering from dry eyes. If someone has a break up time of less than 10s, we are talking about sicca syndrome or simply, dry eyes. We have used this method in clinical trials with products for sicca syndrome but also to assess whether consumer care products disrupt the tear film.
Fluorescein, a dye, is dropped into the subject's eye. They blink a few times and close their eyes. Then the patient opens their eyes and the clock is started. They have to hold the eye open. The slit lamp has a blue light filter, so the fluorescein in the tear film appears as a green layer on the cornea and that layer eventually ruptures. When this happens, I press "stop" on the stop watch and that's the break up time.

That sounds pretty invasive, isn't there a more modern way of doing this?

Yes! We will actually be testing a new device, a so called ocular surface analyzer, to measure the so called non-invasive keratography break up time (NIK-BUT).

What are the advantages compared to the manual method?

The advantage is that you don't have to drop fluorescein into the eye, which can also interact with test products. Everything is measured automatically, and very precisely and accurately. A clinical investigator can measure BUT to the second with fluorescin. This device can measure it in hundredths of a second!

Fascinating! You have been training with the device all morning; could you give me a demonstration?

Sure! Let's get our VP and Director Science and Consulting Stephan Bielfeldt and measure his non-invasive keratography break- up time (NIK-BUT)!

Now what?

First of course, chin and forehead are placed on the headrest and we have to adjust the camera to the cornea. When I start the measurement, the patient has to blink a couple of times and then keep the eye open until the measurement is complete! It will automatically calculate the NIBUT starting with the last blink. You basically just need the patient to not blink long enough and then you hit the "calculate" button!

So, what's his break-up time? 

About 13 seconds! Everything is great! No dry eyes!

So do you think we are ready to go with this device?

Yes, it's a great device and easy to use! But it can do so much more than just measuring break-up time. It can also provide information on the quality of the lipid and aqueous components of the tear film, which could be a valuable evaluation for our sponsors. For example, patient groups can be more accurately differentiated, as sicca syndrome can have different causes - and a particular product may only work in a subgroup of patients!  

So, all in all, what's your verdict on the IDRA?

It's a very sexy device!

Thank you so much for the interview!

My pleasure!

Related content

Case study 'Dry eyes'

Eye tolerability of cosmetic products

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