Article Date: 7/1/2001

Instruments

Instruments and Technology

By John Mark Jackson, OD
July 2001

Sure, it's a cliché, but it's true: a picture really is worth a thousand words. How many times have you wished you had a way to photodocument a lid lesion to monitor growth over time or capture an image of a corneal ulcer to keep tabs on its resolution? Traditional solutions are quite costly: a digital photo slit lamp setup can cost many thousands of dollars beyond the cost of the slit lamp itself. Less expensive systems using film cameras have been available for years, but of course you have to wait for film processing. All in all, a convenient, easy and inexpensive solution has not been available to most practitioners.

Figure 1. Camera lens shown held steadily against the slit lamp ocular.

Go Digital

I have found a way to meet my documentation needs relatively inexpensively. I recently purchased a digital camera for home use, with no intention of taking it to work with me. On a hunch, I decided to try taking a picture of an RGP fit through the slit-lamp, and I was quite surprised by the quality of the result. I have used it over and over again and continue to find new uses for it as well as refine my technique for taking quality digital images.

Before I describe the technique I use for digital photography, I will discuss some essential digital camera features. Look for these features in a camera before you buy:

 

Digitize Your Contact Lens Practice

 

Anterior and Posterior Segment Imaging Although there have been a number of digital imaging systems available in the past, with today's super-fast, large memory computers, advanced software, CCD cameras and improved monitors, they are better than ever. There are many advantages of digital imaging of the anterior segment or fundus with digital as opposed to 35mm or Polaroid imaging or drawing, including speed of capture and viewing and observation of multiple images. With modern, improved, easy-to-use software, excellent multiple images can be captured while you perform a slit lamp examination. You can take multiple images, dump the poor quality ones and store the good ones for future reference. You can send them to another practitioner for consultation. And perhaps best of all you can use them for patient education regarding lens deposits, corneal staining and neovascularization, just to name a few examples. One new ophthalmic image and capture management system is from Haag Streit (www.haag-streit.com) called EyeCap. It is used with the Haag Streit BQ slit lamp and has automatic archiving for ease of use. Security of patient data is considered in the software design.

Improved RGP Lens Measurement Although digital gauges are not new, analog (dial gauge) microspherometers or radiuscopes can lead to dial reading and recording errors. The digital Contacto-Gauge made by Nietz and distributed by Polychem, Inc. USA (www.polychemusa.com) is one example of a modern radiuscope which records to the nearest 0.01mm for base curve measurement using digital technology.

Here is the procedure I use to take pictures through the slit lamp:

Storing and Using Images

Once you have captured your image, you need to transfer it to your computer. The exact method will vary from camera to camera. Some cameras store images on a standard 3.5 inch floppy disk, but most will connect to a computer using a serial or USB (Universal Serial Bus) cable. I would strongly suggest purchasing a camera with a USB connection if you have a USB port on your computer, as transfer times are much faster than with a serial connection (seconds versus minutes). Refer to the camera's manual to determine the exact transfer method.

After the image has been downloaded, you can view it with software that comes with the camera. Most cameras come with some sort of simple photo-editing software package. Once you have your photo on your computer screen, evaluate it for sharpness, brightness and overall quality. Use these qualities to refine your technique. For example, if the photo appears washed out, decrease the brightness of the slit lamp beam or change the exposure setting on the camera to compensate. You can also adjust the brightness and contrast of the image using the editing software, but it is best if you start with a properly exposed photo. If the image is out of focus, you may have to experiment with the focusing of the slit lamp. Also, make sure that you are holding the camera steadily against the ocular as you take the photo.

Figure 2. Camera held several centimeters away from the ocular. Note the image of the ocular and the exit pupil in the viewscreen.

You may choose to simply store your images on the computer, or you may wish to make prints of them to place in the patient's record. Even fairly inexpensive color inkjet printers these days are capable of reasonably good results. Photo-quality inkjet paper or actual glossy photo paper (available at most office supply stores) will be necessary to produce acceptable quality on most printers. The print quality depends strongly on the quality and resolution of the original image. Be sure to always have the camera set on its highest resolution available. Lower resolution cameras (below two megapixels) will not produce quality images above 5x7 inches; more expensive cameras with higher megapixels can produce good larger size prints. You must find a balance between quality and price to suit your particular needs and budget.

Above all, remember that digital images taken in this manner still can't compete with the quality of regular slit lamp slide or film camera prints. For example, it is difficult to capture very fine corneal details like striae or microcysts with this method. However, it is quite possible to get good images of more gross findings such as corneal abrasions or ulcers, contact lens fluorescein patterns, lid lesions, iris detail and the like. A hand-held digital camera can be a simple and reasonably inexpensive way to bring photodocumentation into your contact lens practice. 

 

Figure 3. Camera held against the ocular, prepared to capture an image. Note the image of the eye in the viewscreen.

Figure 4. Entire setup showing patient in position, slit lamp and camera in place and ready to capture image.

 

Patient Education Animation

Through the years I've purchased several pieces of high-tech equipment, and I've recently discovered educational software for eyecare practitioners. This new software is called Eyemaginations, and it has high-quality 3-D computer graphic animations of the eye.

Digital animation from the Eyemaginations software.

Software developer Steve Sopher, OD, and his three sons have produced patient- (and staff-) friendly 3-D animations delivered with oral explanations of eye disorders, refractive errors, spectacle lens designs, eye diseases and eye surgeries ­ all provided instantly to patients in the exam room and/or dispensary.

These full-screen animations are highly detailed and in color. Digital still images can be easily selected to highlight a patient's condition for further explanation. You can also draw on these still images using your on-screen cursor as a marking pen.

The Eyemaginations software is easy to use. While your patient dilates or sits at the optical dispensary, you or your staff member can select the patient's condition(s) from the on-screen library and walk away. The patient sees a thorough description of his condition(s) from the Eyemaginations program.

The current library offers many choices of animations. For example, you can show patients floaters, why their eyes must be dilated, how glaucoma affects the optic nerve and vision or a LASIK procedure. The newest animations include:

Anatomy of the eye from the Eyemaginations library of images

  • Corneal neovascularization formation
  • Dry eye treatment with punctum plugs
  • Contemporary cataract surgery

Patients tell me that they truly understand their condition (such as glaucoma or astigmatism) much better after seeing the program. Because better patient education leads to better compliance, I feel that this practice management tool provides outstanding patient education valuable to any practice.

Dr. Jackson is a faculty member at the Southern College of Optometry in Memphis, TN. He is currently studying the effects of overnight orthokeratology.


Contact Lens Spectrum, Issue: July 2001