If you’ll take a second look at Topcon NW200, you’ll notice that unlike most fundus imaging systems, the unit has no camera-back. The camera-back is a digital SLR camera (usually made by Canon) that actually takes the photo and creates the digital file; the machine itself is just a series of mirrors and lenses in which employs the actual capturing device. The NW200 is different in the sense that it utilizes it’s own CCD camera, and creates the file as an all-in-one unit. Think of other retinal cameras as an individual company whom outsources 75% of its operation. The Topcon is the inverse of that concept, performing all operations in a self contained unit– something that is quite an achievement. This of course comes with its pros and cons; we love the fact that a retinal camera has the ability to capture, record, and store digital fundus files all on a compact-flash card. We dislike the fact that we sacrifice some quality and megapixels by the lack of a serious DSLR camera. Make no mistake, the CCD camera produces suitable retinal photos, however its 3.1 megapixel camera lags behind modern competitors. We understand that since we’re not taking professional photos of a mountain landscape scene, megapixels may be over emphasized in our fundus imaging reviews, however it is the baseline for a quality photo. To add some clarity (pun intended), the NW200 takes great entry-level fundus photos, which can be assessed and diagnosed (from) easily… so long as that diagnosis does not require 5x of magnification zoom on your laptop.
OUR TAKE: A terrific entry-level camera that captures, records, and stores even without ancillary software. The lack of a DSLR camera back will limit post-capture magnification (on your computer), and alignment/focus is up to you, the operator.
#1. Auto Exposure
The NW-200’s CCD camera also hosts an image sensor, capable of automatically adjusting exposure (how much light is allowed into the lens) without adjustment by the operator. This may not seem crucial since the operator controls the flash intensity anyway, however from our testing it made selecting the proper flash intensity much easier, and saved the patient from additional and unnecessary “test images.”
#2. Alignment Not Auto, But Easy
Most modern fundus cameras come with auto-tracking standard, and although the NW200 is an exception, on-screen instructions allow the operator to properly align the optic-nerve head without too much fuss. The unit displays two white dots on the screen that, once overlapped (by the operator making small changes to the joystick) will allow proper alignment. The NW200 also knows when it’s lens is properly focussed; the operator also makes a small adjustment to the two “focus alignment bars” which should align prior to capturing an image. Although it’s not automatic, we had little trouble acquiring proper images.
#3. A Lower Flash Intensity
The sensitivity of the CCD chip allows a lower flash intensity (3.3W) to be utilized, all while simultaneously adjusting the exposure. The flash is somewhat noticeably less intense than what we’re used to, and should allow high-patient compliance.
Yes, we were able to capture decent images in fully-lit rooms, however its best to at least lower the pre-test room lights. The NW200 has a illuminated console via a light just below the FlashCard port, allowing the operator to see the buttons even in fully dark rooms.
3.7mm in diameter.
Yes you can. The NW200 comes with a Compact FlashCard which can be removed from the unit and stored images viewed on a computer. The FlashCard will not allow patient information to be stored, therefore IMAGENET viewing software from Topcon may make it more efficient.
45° is the maximum field of view.