Self examination with the OCULUS Keratograph 5M. (Images: Ralf A. Niggemann)
Self examination with the OCULUS Keratograph 5M. (Images: Ralf A. Niggemann)


Eye to Eye

The new Keratograph 5M from OCULUS is an instrument of many talents. For ophthalmologists and opticians it is the smart phone among diagnostic products. It makes light work of analysis, diagnosis and documentation in everyday practice.

As an eyeglass wearer I’m happy to try it out myself – not at the optician’s, but in the showroom of the OCULUS company’s headquarters in Wetzlar. The experts I put my trust in are not ophthalmologists either, but competent OCULUS staff.

“Please take a seat and make yourself comfortable,” says product manager Nicole Mothes. Sounds reassuring enough. Almost silently, an instrument glides into my field of vision, its shape vaguely reminiscent of an oversized shower head. Even without my specs on, I immediately realize that we’re not talking about jets of water here but rays of light. My chin is on the chin rest, my gaze is fixed on the center of the calotte in front of me. So I’m looking right into the “heart of the topographer,” as Nicole Mothes tells me. Using the Placido ring illumination it is possible “to map the cornea of the whole eye with thousands of measuring points. In the center of the calotte there are also white, blue and infrared diodes that provide the perfect illumination for every function.”

Quick non-contact examination

This is going to be complicated, I think, but everything is really quick and simple. I’m to keep my eyes open for as long as I can, then blink, first once and then twice in quick succession. While I’m doing this, infrared, blue or white rings are alternately projected onto my cornea. I follow the instructions as closely as possible, after about two minutes the non-contact examination is over.

All the data has been captured, the relevant measurement results determined. I’d been expecting numbers, but I am shown images: colorful 3D images resembling topographical maps as well as digital camera images, even video sequences. I’ve definitely never seen my eyes like this before. Talking to Nicole Mothes, I find out what I’m really seeing here: the surface of my cornea, the quality and quantity of the tear film, the tear film dynamics, the state of the oily lipid layer, the so-called meibomian glands, whose dysfunction is one of the main causes of dry eyes, and last but not least, conjunctival irritation. The results of the examination are clearly shown on a screen, compared with the specific limit values and commented on by the expert.

No comparable tool on the market

For a lay person like me, this is naturally extremely fascinating. But I can tell that Nicole Mothes finds the topographer equally impressive. “There’s no comparable tool on the market that combines so many functions in such a compact form.” For several good reasons the Keratograph 5M is able to demonstrate so many talents. The criteria for optimal fitting of contact lenses have changed in the last few years. When OCULUS presented its first corneal topographer in 1995, its original basic function was to measure the surface of the cornea. The system was further developed to map the cornea as completely and in as much detail as possible with the ring structure. With the aid of the fluo image it was also possible to measure the fit of the contact lens on the cornea and correct it if necessary.

The latest OCULUS Keratograph 5M can still do all that – but much better. And it can do a lot more besides. “A crucial factor when fitting contact lenses is the tear film. Nowadays, a thorough and detailed analysis of the tear film is an essential part of the preliminary examination,” stresses product manager Kai Mothes. It takes account of all the specifications that have already been determined in my trial session: the quality and quantity of the tear film, the tear film dynamics, the state of the oily lipid layer and the meibomian glands.

The result is automatically compared with limit values

The ring structure of the keratograph is the systemic basis of the above-mentioned measurement functions. The illumination function acts like an optical matrix, the digital imaging technology as visualization and documentation medium. Beside these hardware components, the sophisticated software also plays a significant role, “translating” the image information into data and information of relevance for the examination. For instance, the ring structure enables the quality of the tear film to be determined. Any breaks in the tear film are recorded as a video sequence, while the software labels the “neuralgic” zones in real time. The measurement of the tear film quantity, on the other hand, which used to be done with the split lamp microscope on the basis of subjective empirical values, is performed in the Keratograph 5M with a ruler function and the result is automatically compared with limit values. This is unique so far.

The Keratograph 5M even goes a step further by analyzing the lipid layer, which is of great significance for the tear film. How thick is this oily lipid layer? How does it react to foreign bodies? Is it fulfilling its protective function adequately? To answer these questions, the movement of particles on the tear film after the patient blinks is examined in micrometer detail. This provides information on the quality of the lipid layer, which is not only a criterion for the choice of contact lenses, but also of the care products. One of the innovative features of the new keratograph is the meibography function. This analyzes the so-called meibomian glands, which produce the lipid layer on the tear film on the inner surface of the upper and lower eyelid. Early diagnosis is particularly important here, as degeneration or dysfunction is not (yet) curable. The homogeneous illumination of the keratograph and the software also make it possible for the first time to determine the level of conjunctival irritation.

Quality “made in Wetzlar”

It’s quite special for a single instrument to offer such comprehensive examination, diagnosis and documentation capabilities. The quality of the individual functions is often compromised in highly complex integrated systems. This is not the case with the OCULUS Keratograph 5M. Featuring superlative display quality and frame rate, the digital CCD camera is based on the latest technology standards and, like the other hard- and software, was developed in the company. So at OCULUS, top quality means “Made in Wetzlar”. In the pre-development stage, the OCULUS experts collaborate closely with universities such as the University of Applied Sciences of Central Hessen (THM); whereas as far as application technology is concerned, the company forges early links with users to find out their requirements and design the perfect instrument for everyday use.

“After all, the aim of the preliminary eye examination is to get dependable measurement results to provide the basis for a reliable diagnosis. We support our users with ultra high-quality and effective instrumentation for this purpose,” says Kai Mothes. And customers appreciate the fact that this support is based on expertise that is unparalleled in the industry. The German market launch of the OCULUS Keratograph 5M was highly successful. In the USA, where there is current extensive research into the medical effects of the increase in VDU work, the keratograph has already tapped another large market.

So the preliminary assessment of the OCULUS experts is a hundred per cent positive. The same applies to the measurement data and results supplied by the Keratograph 5M in my case. Except for a few negligible peaks in the topography of my cornea, all the data suggest that I could wear contact lenses. I’m also told which lenses would be suitable. Shall I stick with my specs? I’ll think about it.


Additional Information:


The calotte is the heart of the Keratograph 5M.
The calotte is the heart of the Keratograph 5M.
Nicole and Kai Mothes explain the manyfold functions of the Keratograph 5M.
Nicole and Kai Mothes explain the manyfold functions of the Keratograph 5M.