Ophthalmoscope goes digital

30 Jul 2004

A UK team is looking to speed up diagnosis of eye disease by capturing electronic images of the retina

A prototype smart-ophthalmoscope that takes digital photographs of the back of the eye has been developed in the UK. When commercialized, the instrument will allow electronic images of the patient's retina to be transferred directly from opticians to specialist clinics. The approach could ease the burden on eye hospitals and speed up the diagnosis of potentially blinding conditions such as diabetic eye disease.

Currently, the majority of high street optometrists have no objective method of recording images and instead rely on notes and sketches, leading to a large number of clinic referrals.

A prototype of the handheld device was demonstrated at the Smart Optics Project Review Forum in London earlier this month. It is the result of a 3-year UK project which kicked off in Sep 2002 to develop a non-contact, high-resolution (>100 microns) technology demonstrator.

The partners in the project are: Keeler; Davin Optronics; Sira Technology; University of Warwick; UCL School of Ophthalmology and City University Applied Vision Research Centre

The £450 000 government and industry backed project is just one of several projects within the Smart Optics Faraday partnership which is sponsored by the DTI, PPARC and EPSRC.

Fred Fitzke of UCL hails the new device as the biggest advance in hand-held ophthalmoscopes in 100 years. Certainly the ophthalmoscope, which acts as an illuminated microscope formed by the eye of the optometrist and the patient's own eye, has changed little in design until now.

"It's like putting man on the moon - we knew what to do, but it was a case of waiting for the technology," City University lecturer Luis Diaz Santana told Optics.org. Their main hurdle was finding a high-performance colour CCD camera that was small enough for what had to be a hand-held device.

The solution turned out to be a 1360x1024 pixel camera measuring 39x39x68 mm supplied by the German firm PCO. The team fitted its own custom optics.

"We needed access to gain and colour balance channels to process a true colour image," said Diaz-Santana, acknowledging the importance of colour in the diagnostic process.

Ergonomics also played a key role in the design, with UCL responsible for looking at how health professionals use the device. "You have to get the optics as close as possible to the patient's eye to increase the field of view" Diaz-Santana explained. "If you're too far away it's reduced by the patient's pupil." Warwick University engineered custom lens mounts to shrink the size of the prototype.

Precision optics specialist Davin Optronics is on board for the final round of product development, with UK ophthalmoscope manufacturer Keeler driving the commercialization program. Keeler's Clive Burrows told Optics.Org that they hope to launch a product in 2005.

Author
James Tyrrell is reporter on Optics.org and Opto & Laser Europe magazine.