Cirrus 400

Carl Zeiss eyeSITE eNewsletter

Introducing the Cirrus HD-OCT Model 400

Carl Zeiss is proud to announce the release of a second model of the world’s best selling spectral domain OCT system; the Cirrus HD-OCT. The new model is called the Cirrus HD-OCT Model 400 and will be offered in addition to the premium Model 4000. This brings our OCT family up to four as shown below.

Time Domain OCT	Stratus OCT (Retinal & anterior OCT)
	Visante OCT (Dedicated full functionality anterior segment OCT)
Spectral Domain OCT	Cirrus HD-OCT 400 (Retinal & anterior segment OCT)
	Cirrus HD-OCT 4000 (Retinal & anterior segment OCT)

What’s unique about Model 400?
Focused on the essential core OCT functionality, Model 400 is designed with the smaller budget in mind by ingeniously generating a high quality fundus image with the OCT scanner itself using patented Live OCT Fundus™ technology. Current Cirrus HD-OCT users have always been able to view the black and white OCT fundus image either as an overlay on the LSO image or beside the ETDRS grid on the Macular Thickness Analysis screen/print-out (see figure 1), but it has never before been used as a live image for alignment purposes until now.

This differs from the premium Model 4000 which uses a Line Scanning Ophthalmoscope (LSO) to generate the live fundus image. The LSO works like a flat bed scanner by sweeping a line across the retina to produce a very crisp, clear black and white fundus image.

So how does the Live Fundus OCT™ compare to the traditional LSO fundus image? The answer is two-fold. Firstly, the LSO scans faster than the OCT so for the operator lining up the OCT, the refresh rate of the image is faster with the LSO. Secondly, the LSO provides a sharper image.

A second contrast between the two models is that the Model 400 will not feature the HD Enhanced Raster Scan. As described in the previous article, the Enhanced HD Raster Scan uses Selective Pixel Profiling™ technology to reduce image noise while enhancing anatomical detail.

Other than these two points, the differences between the two models are minor. Both models offer the same package of glaucoma and retina analyses and are capable of anterior segment imaging. The dense data cubes are interchangeable between Model 400 and Model 4000 systems and they share the same modern integrated design, ease of use, and small footprint.