The Topcon DC-4
Dr Huw Pinney on the DC-4 slit lamp mounted camera
During my career I have generally shied away from slit lamp mounted cameras as I've not been impressed with the image quality of the integrated cameras and have found that the heavy SLR cameras impair the ergonomics of the slit lamp in normal use. However, this changed when Topcon combined its new DC-4 digital camera with LED illumination in the SL-D701 slit lamp.
The mind changer
The DC-4 camera is neatly integrated into the observation system of the slit lamp and does not affect the performance, or handling, of the microscope. It uses a five-megapixel CMOS chip, which provides more than enough resolution for detailed image capture.
The LED illumination provides a light source that is brighter than conventional halogen bulbs, while the shorter wavelength light enhances the view of anterior segment structures and anomalies such as flare in the anterior chamber. But it is not until I, on occasion, revert back to a halogen-illuminated slit lamp that I realise just how much of an improvement the LED illumination makes to detailed observation.
The camera is really easy to use and, in auto-exposure mode, all variables such as aperture, shutter speed and white balance can be set to automatic, which, for the vast majority of imaging, works very well.
Once the DC4 software is running on my desktop computer and the patient is selected, the images can be taken by simply pressing the button on top of the joystick. An immediate live view is also provided, which means that a third party accompanying the patient can see the slit lamp view in real time on my desktop monitor. High definition video capture at 24fps is also available by simply selecting it from the software control panel and pressing the joystick button to start or stop the capture session.
Like all image acquisition equipment, this camera enables the creation of a permanent record of any abnormality or otherwise.
Certainly for me, as I lack artistic flair, my fundus camera and now anterior segment camera are an essential part of my record keeping.
Interestingly, it is possible to record fundus images with the DC-4 in conjunction with a Volk lens. Though I would say that the image is of lower quality than for the anterior segment images, it does provide a means of recording peripheral fundus abnormalities occurring outside the normal field of view of a conventional fundus camera.
"During my career I have generally shied away from slit lamp mounted cameras...this changed when Topcon combined its new DC-4 digital camera with LED illumination in the SL-D701 slit lamp"
I also find the DC-4 very useful in contact lens work, particularity for recording lens fitting patterns with fluorescein, as well as lens movement with the video option. It gives me the opportunity to revisit the fitting process after the clinic when I have more time to think about the next stage, especially for more complex, rigid lens fits, for example, in keratoconus.
Where the camera is particularly useful is for patient education and as an aid to communication. If you can show a patient the scratched, chipped or heavily deposited contact lens that’s in their eye, it becomes much more personal for the patient and they are more likely to adhere to a care regime or understand why a new contact lens is required.
In a similar way, it facilitates the conversation when a more advanced or premium material is required, for example, in cases of corneal neovascularisation.
I find the DC-4 equally useful in managing patients with dry eye and blepharitis, from photographing superficial punctate keratitis and anterior blepharitis, to filming incomplete blinks, poor tear break-up time and poor expression of meibomiam glands.
Another useful feature involves utilising the camera and illumination infra-red settings, which enables the observation of the meibomiam glands and facilitates the management of meibomiam gland dysfunction by imaging meibomiam gland dropout.
In conclusion, I find the DC-4 slit lamp camera a very useful addition to my equipment list, particularly with respect to managing contact lens patients and patients with dry eye. Most importantly it facilitates patient education and management, as well as enhancing the quality of care.