Slit-lamps: digital and photographic on a par

May 19, 2008

Diagnoses using digital slit-lamp images are comparable to diagnoses using 35 mm photographic slides for some anterior segment abnormalities, according to a study published online ahead of print in Eye.

Diagnoses using digital slit-lamp images are comparable to diagnoses using 35 mm photographic slides for some anterior segment abnormalities, according to a study published online ahead of print in Eye.

Sajeesh Kumar of the University of Western Australia and team compared digital images from a portable slit-lamp camera with 35 mm slit-lamp photographs and traditional ophthalmic assessments in anterior segment disorder detection.

A total of 196 patients (392 eyes) were recruited from an anterior segment ophthalmology clinic. Each patient underwent an examination by an anterior segment ophthalmologist. Two to three standardized views of 640x480 pixel digital images (portable digital slit-lamp camera) and 35 mm photographic slides (Zeiss slit-lamp camera) were taken after the examination. The same ophthalmologist reviewed the images in a masked fashion. Two other masked graders also assessed the digital images. The presence or absence of 33 specific findings was noted at each examination.

Digital images showed moderate to excellent agreement to clinical findings (x 0.45–0.82) in areas other than lid pathologies. Lens findings from digital images had moderate to good agreement with the clinical gold standard (unweighted x 0.43–0.65, sensitivity 59–77%, specificity 86–94%). Gross cornea signs were well detected with digital images, (x 0.72–0.85, sensitivity 67–100%, specificity 98–99). More subtle corneal, conjunctival and lid abnormalities, however, were not identified well. The statistical figures were very similar to the above-mentioned figures when the 35 mm film results were compared with clinical diagnoses. The two image formats showed better agreement when compared with each other than when either is compared with clinical findings.

Overall, the researchers were able to conclude that digital slit-lamp imaging offered no clear advantages over 35 mm photographic slides when diagnosing certain anterior segment disorders.