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The retinal camera is a valuable diagnostic and screening tool that is underused in most optometry practices, according to an expert.
"The retinal camera is often looked upon as a tool for documentation, but it can do more," said Dr. Fingeret, speaking here at Vision Expo East. "It can be part of the examination, as another method to complement the assessment of the back of the eye. It does not take the place of any other test, but it can be done in addition to other tests."
Dr. Fingeret used glaucoma as an example of a condition in which patients would benefit from screening with retinal cameras. He noted that there are limitations associated with using IOP as the sole screening test for glaucoma: One-third of glaucoma patients have IOPs of less than 21 mm Hg, IOP can vary throughout the day by as much as 10 mm Hg, and IOP is affected by systemic medications.
"Diagnosing glaucoma is difficult," Dr. Fingeret said. "Fifty percent of glaucoma [cases] are undiagnosed, and some may go undiagnosed even after having an eye exam."
This means it is time for a different line of thinking. Dr. Fingeret cited a finding from the Ocular Hypertension Treatment Study, published in the December 2006 issue of Ophthalmology, in which 84% of optic disc hemorrhages were not recognized in real time, but were recognized with retinal photographs.
"Hemorrhages were seen on the photograph that were not noted by the examining doctor," he said.
According to Dr. Fingeret, one way to improve optometrists' diagnostic skills would be to have them all undergo subspecialty-type training to enhance their ability to perform an optic nerve evaluation. But, "on a practical basis, this is not possible," he added.
Include screening tests
Another method to improve detection is through the use of screening tests, such as the retinal camera or screening perimetry, as an integral part of the routine examination.
The value of retinal cameras doesn't extend only to the realm of glaucoma. The Department of Veterans Affairs uses digital retinal photography as a screening tool for diabetic retinopathy, Dr. Fingeret said.
The protocol is to obtain four images each in 45° fields: the optic nerve, macula, mid-periphery, and an external image. The process takes about 5 minutes per eye. About 20% to 30% of the images are ungradable if obtained through non-dilated pupils. The percentage is lower when a younger patient population is analyzed, and can be improved to 4% when pupils are selectively dilated.
Another reason to make more use of the retinal camera-most optometrists already own one and use it to document optic nerve and retinal conditions. All practitioners need to do is bring the camera from the back end of the examination process into the front end.
"Retinal cameras are valuable diagnostic and screening tools," Dr. Fingeret said. "They don't take the place of other parts of the exam but can be used to complement other parts of the exam.
"You still need to dilate, still need to look closely at the back part of the eye with ophthalmoscopy. It doesn't take the place of that, it complements it. It provides a little different view."
Murray Fingeret, OD, FAAO
Dr. Fingeret serves on the advisory boards of Alcon, Allergan, Pfizer, Carl Zeiss Meditec, Optovue, Topcon, and Heidelberg. He is a consultant to Allergan and Carl Zeiss Meditec. He has received research support from Heidelberg, Carl Zeiss Meditec, and Optovue.