Article Date: 1/1/2011

Get the Picture on Buying a Camera
diagnostic equipment

Get the Picture on Buying a Camera

Before buying a digital fundus camera, ask these questions, and see the answers that make the purchase a good idea

Robert Murphy, Contributing Editor

A digital fundus camera's utility as a means of enabling you to follow chronic and progressive retinal or optic nerve changes and its documentary capacity make it an invaluable diagnostic aid. (See “Digital Fundus Camera Applications,” below.) That said, purchasing one, as is the case with purchasing any diagnostic equipment, can be a daunting task — unless, that is, you know the questionsw (See “Digital Fundus Camera Websites,” below.)

Here, glaucoma and retinal disease specialists provide you with these questions and answers.

What is the camera's resolution?

A camera that offers more than 5 megapixels provides the detail needed, says Andrew S. Gurwood, O.D., F.A.A.O., Diplomate and professor of Clinical Sciences at The Pennsylvania College of Optometry, Salus University, in Elkins Park, Pa.

“The resolution question should be asked prior to purchasing a camera, so that you have the ability to compare one product to another. However, since a camera is a device which records the event for future comparison and is not the tool intended for diagnostic activity — unless it is being used as part of a telemedicine program — resolution alone should not drive the decision,” he explains. “A camera with adequate, not the best, resolution is likely fine if it comes with other features [explained below].

What is the camera's field of view?

Most digital fundus cameras offer two standard fields of view: 20° and 40°. Accordingly, these standard fields of view typically come with variable magnification settings.

“You want a wide angle of view as well as a more detailed one. The wide field gives the ability to encompass a great deal of the fundus, which is good for comparing things [pathology] over time when there are more anatomic landmarks in the shot,” explains Joseph Sowka, O.D., F.A.A.O., Diplomate, professor of optometry and chief of the Advanced Care Service and Director of the Glaucoma Clinic at Nova Southeastern University College of Optometry, in Fort Lauderdale, Fla. “Then, a detailed view photo can be taken for better inspection. Detailed field photos are necessary for photographing the optic disc for glaucoma management. You should have a camera that allows you the versatility to take a picture maybe out as far as the equator of the fundus, or more, and then also a magnified photo of the optic disc.”

What kind of features should the camera have?

Dr. Sowka says the camera should be able to take stereo photos of the optic disc, as stereo disc photos are considered the gold standard for analysis of the optic nerve and judgment of glaucoma progression. In addition, he says the device should have the ability to preferentially examine through filters more details in the retinal nerve fiber layer as well as the choroid.

“Filters that identify and highlight the retinal nerve fiber layer are especially helpful in identifying defects indicative of glaucoma,” he explains. “Filters that isolate the choroid are helpful in localizing lesions to that layer.”

Leo Semes, O.D., a professor of optometry at the University of Alabama at Birmingham College of Optometry, in Birmingham, Ala., adds that the camera should have the ability to enhance brightness and contrast, overlay photos to provide a comparison from baseline and present the right and left eye side by side or tile several images.

Dr. Gurwood adds it should have these features as well:

A minimal footprint with a comfortable, backed, adjustable chair, allowing equal access to an adjustable forehead bar and chin rest for all patients (including wheelchair-bound patients).

“A minimal footprint will conserve space in the office. A comfortable, backed, adjustable chair will prevent falls, add support and ensure comfort during the process,” he says. “The physical layout of the device should allow access for wheelchair-bound patients. An adjustable table will permit greater flexibility for positioning more individuals.”

► An internal and external fixation target for ease of orienting the eye for photo capture.
► An adjustable flash intensity, allowing variable settings to permit the examiner to properly illuminate the areas that require documentation.
► The ability to compensate for large hyperopic and myopic refractive errors.
► The ability to capture quality images in conditions that don't require mydriasis.
► The ability to acquire magnified images separate from the digital options for manipulating the images “after-the-fact.”
► A hard copy output so a physical photograph of the images can be used in a paper file and kept as a back-up.
► A large video display positioned for easy viewing by both you and the patient — the latter for educational purposes.

Is the camera easy to use?

Take the digital fundus camera you're interested in for a “test drive.” If you plan on having your technicians operate the device, be sure they can operate it with ease as well.

“The instructions for capturing a basic fundus image should be straight forward, such that anyone can be trained to take serviceable photos in less than 15 minutes,” says Dr. Gurwood.

Will the vendor “support” the device?

A vendor that supports the camera generally meets these criteria, says Dr. Gurwood:

► Provides training for you and your staff on the device.
► Provides a minimum of a one-year warranty, with service agreements purchasable.
► Provides reasonable repair costs after the warranty expires.
► Provides easily accessible technical support during your hours of operation.

“When I got my camera, it wouldn't take clear pictures. Something had happened during shipping, which misaligned the focusing system,” Dr. Gurwood explains. “I placed a call to the vendor, and he was in my office the next day.”
► Lets you know what is reparable and replaceable.
► Provides a loaner camera if yours can't be fixed at your practice.
► Provides references from camera owners. (Note: Consider inviting comment from colleagues on optometric-themed websites.)

Is the camera compatible with my office information systems?

If you have electronic health records (EHR) now, you should have a camera that's compatible with that, and makes it easy to upload the photographs, explains Dr. Sowka. Most are.

“Or, if you have a camera now that you're fond of and don't want to replace anytime soon, you should make sure it's compatible with whatever EHR system you're looking at.”

How do I code for fundus photography?

The economics of billing for photography make it a practice-revenue builder, if, that is, you code appropriately for it. Coding and reimbursement for fundus photography is fairly straightforward. Although reimbursement may vary by region, fundus photography has the diagnostic code 92250. Remember when billing to cite the clinical rationale. Camera company representatives can be a valuable resource on how to bill for fundus photos. Naturally, they have an interest in seeing you get the most of the equipment.

For all their utility, even the best fundus photos cannot replace a careful and thorough dilated fundus evaluation. Nor are they designed to do so. But, their benefits are many, from following chronic and progressive retinal and optic nerve disease, to providing patient education, to thorough record keeping and providing a consult. By asking the questions outlined and using the answers provided as your guide, you'll be armed with the information you need to make the right purchasing decision. OM

Robert Murphy is a freelance writer based in the Philadelphia area. He has spent several years reporting on the eye-care fiield. E-mail him at rmurphy2000@verizon.net, or send comments to optometricmanagement@gmail.com.

Digital Fundus Camera Applications
Three ocular conditions, in particular, benefit greatly from serial fundus photos: diabetic retinopathy, glaucoma and age-related macular degeneration (AMD).
“With the almost epidemic proportion of diabetes, monitoring every patient who is diabetic, pre-diabetic or at risk for diabetes with photography — even on those patients who don't have overt fundus signs by clinical observation — becomes important,” says Dr. Semes. “The number of microaneurysms that you count, and the way you would stage the patient's diabetes really are dependent on those photographs, in addition to your clinical observation.”
Dr. Sowka adds that digital fundus photos aid the clinician in identifying neovascular disease in diabetic retinopathy patients — something he says may be missed clinically. “The patient may be mischaracterized as having nonproliferative disease when he actually has proliferative disease,” he explains.
In glaucoma patients, glaucoma suspects, those who have ocular hypertension and those who have a family history of glaucoma, fundus photos are an excellent means of following changes in the optic disc's architecture and any evidence of nerve fiber layer dropout, says Dr. Semes.
“I see so many times in our clinic where the patient went to our primary care clinic for their first visit to an optometrist,” he says. “And maybe their intraocular pressure was a little bit elevated, and it was said, ‘well, come back in a year.' So the patient comes back in three years, and now the nerve is much more suspicious than at the initial visit.”
Dr. Sowka adds, “It's nice to go back to those patients you've identified as a [glaucoma] suspect and take a picture. Then, you can see things that you might have missed clinically. “Very frequently nerve fiber layer defects can be missed clinically. Disc hemorrhages in glaucoma or ocular hypertensive patients are missed clinically very frequently.”
In the case of AMD, Dr. Semes says digital fundus photography is “critical” in helping the practitioner grade the degree of dry AMD, and therefore, determine whether Age-Related Eye Disease Study (AREDS) nutraceutical intervention is warranted. “AREDS revealed that certain patients were low risk for AMD and probably didn't need a supplementary formula,” he explains. “But for those at high risk, it was clearly beneficial.”
In addition to helping you manage these three ocular conditions, Dr. Gurwood adds that digital fundus photography is useful for documenting congenital anomalies, such as nevi, retinal pigment epithelial hypertrophy, congenital hypertrophy of the retinal pigment epithelium, unusual vascular findings, such as cilioretinal arteries, congenital retinal vascular tortuosity, congenital retinal macrovessels and retinal arteriovenous malformation.
“These devices [digital fundus cameras] also enable the documentation of infectious and inflammatory changes in the posterior segment that are just as likely to occur in the young as they are the aged,” he says. “And, they're great for recording every patient, regardless of ocular health, so a record exists of the patient's baseline findings. The bottom line is that you will use the camera a lot more than you think.”
Finally, Dr. Gurwood says he appreciates the fact that digital fundus cameras allow him to both obtain and provide images to colleagues for consulting purposes. “There have been multiple times when I've had a photo I've wanted to get a second pair of eyes on, and colleagues have sent me images to review as well,” he explains. “Being able to send and receive a clear, high-resolution photo via e-mail has been really convenient and has expedited the decision-making process, in terms of management.”


Optometric Management, Issue: January 2011