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CLINICAL

32 OPTICIAN CLINICAL 13 January 2017

Broadening your scopeINSTRUMENTSCLINICAL

As 2016 drew to a close, I managed to get my hands on the new Fundus Module 300 (FM300), distrib-uted in the UK by Haag Streit UK; a fundus camera designed to be added to the slit lamp to extend the imaging capabilities of a slit-lamp assessment (fig-

ure 1). In design, the FM300 is not dissimilar to the Volk Pictor Plus (Optician 11.12.15) or the Nidek VersaCam (Optician 24.06.16) but is distinguished by it being built primarily for use at the slit-lamp rather than as a portable imaging system (as are the other two). This means its design is focused solely on better slit-lamp integration, to exploit the stability offered by the slit-lamp and the image manipulation capabilities offered by the optics of the slit-lamp and the image capture software used.

FM300The specifications of the FM300 are outlined in table 1. I used the camera mounted upon the Haag Streit slit-lamp BQ900 (figure 2) but can see no reason why the system could not be incorporated into any modern HS-style slit-lamp. As the system I used included an integrated slit-lamp imaging system, it meant I could simply toggle between the fundus and the anterior imaging systems by a click of either the fundus imaging icon (figure 3) or the slit-lamp imaging icon (figure 4) on the linked computer touchscreen.

The FM300 comes with a small stand/charging unit (figure 5) easily stored on or near the slit-lamp unit and offers five hours use if charged over the preceding night. When needed, it simply plugs into the adapter set into the microscope pivot top (figure 6) and is

Bill Harvey tries out a new camera designed to increase the image capture capabilities of your slit-lamp

ready to use. This positioning means it can easily be swung into the correct position when required, or off to the side when stand-ard slit lamp viewing or imaging is needed (figure 7). This, in my view, is its best design feature as changing from anterior to fundus viewing is almost seamless.

IMAGE CAPTUREOnce fundus capture is selected and the camera positioned before the patient, it is simply a matter of moving to the position where the clearest image on the camera LCD screen is offered. If the slit-lamp you have does not include imaging software, it is perfectly possible to capture an adequate anterior image using the FM300 (figure 8a). This might be acceptable for monitoring or demon-strating gross lesions but will never replace the detail of a dedicated anterior imaging system (figure 8b).

For fundus imaging, you simply move the camera towards the pupil of the patient (pupils of less than 4mm diameter proved tricky) until the retina comes into view and position indicators onscreen suggest appropriate positioning. Unlike with handheld

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Compatibility Haag-Streit slit lamps: BQ 900, BP 900, BI 900 and BM 900

Image sensor CMOS, 5 MP

Image resolution 1536 x 1152 pixels

Field of view 40°

Focusing Auto or manual

Diopter compensation -20 D to +20 D

Illumination Infrared LED for aiming, visible white LED for imaging

Battery Rechargeable Li-Ion Battery

Usage time Approximately ꢀ ve hours with full battery when connected to slit lamp via USB

Display 3.97”, 800 x 480 pixels

Camera interface USB 3.0

Software EyeSuite Imaging

EMR interfaces EyeSuite script language, DICOM (SCU), GDT

Operating system Microsoft Windows Vista, Windows 7, Windows 8.1, Windows 10

Cradle Charging position and storage

TABLE 1 FM 300 Specifications

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13 January 2017 CLINICAL OPTICIAN 33

INSTRUMENTSCLINICAL

devices for portable use, I found best image capture using the ‘auto’ function, and a few seconds after pressing the capture but-ton, a 40º fundus view appears on screen. The first thing I learned was that the light setting on the unit is essential. For a wide-pupiled student, the default setting was too much and gave a ‘white-out’ image (figure 9). Note also on this image how there are some image enhancement scrolls across the bottom of the screen. This means that, immediately after image capture, it is possible to make minor adjustments to contrast, brightness, col-our and so on to achieve the best image quickly. Figure 10 shows a typical image of a healthy subject using the correct light setting and figure 11 shows the subtle improvement after a quick enhancement on screen. The detail here is certainly adequate to detect most significant lesions and also, by displaying the images from each eye onscreen adjacently, significant differences, for example between the discs, may be assessed. A red-free image dis-play is easily achieved too (figure 12). Figure 13 shows one of my images taken through a Volk lens – admittedly not my best, but it does serve to remind how the extra field offered by a unit like the FM300 enhances viewing capability.

For those patients with smaller pupils, capture with the FM300 is not always straightforward and I had many an image with shaded or white-out encroachment. A way around this for these patients, I found, was to start with the nasal fixation target (by a simple touch on the camera screen it is possible to move the fixa-tion target, seen by the patient as a flashing green light) such that the image is centred at their disc. I have not yet worked out why this might be, but I was always able to achieve a better image this way (figure 14) when standard fixation proved tricky. Figures 14a and 14b also show how changing the camera light setting alters the view. Figure 14a has a better overall clarity, while the brighter 14b has better representation of the tigroid retinal appearance but some loss of inferior image.

Figures 15 and 16 show some drusen changes and figures 17 and 18 show naevus changes.

CONCLUSIONThe FM300 offers an easy way of capturing a good quality fundus image during a slit-lamp assessment that adds very little time to the session. In combination with an anterior imaging system, it offers the practitioner the capability of a full overview of accepta-ble quality that is easily incorporated into the routine. Though never designed to replace dedicated retinal image capture, its easy incorporation into the slit-lamp assessment does, in my view, enhance screening and monitoring capabilities without adding to any time constraints. If further developments, such as image mosaic and perhaps even autofluorescence appear, then this will become a yet more attractive slit-lamp extension. •Further details from haagstreituk.com.

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