Precise measurements, randomization and ease of use with children are among the advantages to digital systems.
About 15 years ago, I noticed that the acuity charts in the two exam rooms at my practice looked different, namely the contrast. Specifically, one appeared more yellow and darker. Given that I was doing sports vision, in which contrast sensitivity is extremely important, this was less than ideal. If I want to test the patient at 20% contrast, I don’t want 20% contrast +/-5%.
I realized it was time to upgrade my exam rooms with a digital visual acuity chart, and I’ve never regretted it.
If you still rely on a standard projector, there are several reasons to consider an upgrade. Perhaps the biggest one is the precision of the visual acuity measurements, particularly contrast. Consider: With a traditional system, the slide ages, and the bulb begins to yellow or decrease in intensity. The contrast of the target, in turn, also decreases in intensity, so you’re no longer assessing visual acuity in the classical sense.
Some additional advantages:
• You can randomize the letters and images. That way, patients don’t memorize letters as they read from one eye to the other.
• Digital visual acuity systems often have several different kinds of charts. These include Snellen letters, Sloane letters, pictures and numbers, so you can use whichever you prefer. There are specialty charts built into most of them, such as in the ETDRS chart, which is particularly important if you’re collecting data as part of a clinical study.
• They’re ideal for pediatric patients. Besides a Snellen chart, systems also have built-in HOTV testing and numbers. You can also insert an arrow and toggle it to the specific symbol or letter you want the child to identify. For preverbal children, you can ask them to select a handheld card that matches the image on the screen. In addition, some digital acuity systems allow you to project cartoons to the other end of the room to keep the fixation of pediatric patients as you perform retinoscopy and ophthalmoscopy.
There are some additional steps you can take to ensure a positive experience. Some specific things to ask:
• What is the company’s customer service like, and what warranties does it offer? Does the company provide support in setting up the system in your office and training you to use the equipment? Does the company offer technical support, and will it replace any parts of the system that break?
• Can your employees use it? Given that your staff probably does pretesting, they should know how to use it as well.
• Are software updates included and, if so, for how long? For example, if the company updates the software to improve image quality, is this included in your purchase price? Ask to compare two systems. If one system offers you unlimited updates for one year while another offers you unlimited updates for five years, which are you more likely to choose?
• Does the system qualify for the Americans with Disabilities Act tax credit?
• What financing options are available, and how can you pay it off?
The experience in adding digital acuity charts to my practice was easy, and the learning curve was rapid. Most work by remote control, with the images projected directly ahead. Or, you can use the systems in a mirrored room, which allows you to put the eye chart behind the patient, an advantage in narrow exam rooms, and most companies will help you set up the system.
David Kirschen, OD, PhD, has been team optometrist for several professional sports teams, in MLB, NBA, NHL and with the U. S. Olympic Team. He is director, Binocular Vision and Orthoptic Services, at Jules Stein Eye Institute, University of California-Los Angeles; vice president and cofounder, EYEcheck Systems; and owner, Customized Vision Care.
EXAMPLES OF DIGITAL ACUITY SYSTEMS
|ACUITY PRO | 877.228.4890 | AcuityPro.com|
|Acuity Pro Digital
|• Software only or all-in-one systems
• Free tech support – telephone and email support options
• 56-key custom remote
• Smart randomization, multiline display choices, three letter sets for each line
• Customizable image and video playlists
• Charts: Snellen, Sloane, number, six standard ETDRS charts and illiterate charts, including pediatric symbols, HOTV, tumbling C and tumbling E
• English, metric, decimal, or LogMar display
• Smaller increments of larger optotypes for low vision
• Includes patient education slides and cartoons as fixation target for children
|M&S TECHNOLOGIES, INC. | 877.225.6101 | MSTech.eyes.com|
|Smart System 2
|• All-in-one visual acuity and contrast sensitivity testing system that installs easily in mirrored and direct exam rooms
• CPU with 22-inch screen and Customizable Software
• Ability to integrate with autorefraction systems
• Includes patient education videos Smart System Tablet Technology, Glare Testing System (GTS), CustomLink, Electronic Low Vision Testing (eLVT), ATS and eETDRS, contrast testing that is validated to the Pelli-Robson charts, sine wave grating contrast, Landolt Ring and ETDRS Contrast Testing and Protocol One
• Same features as Smart System Standard but faster processor
• Increased RAM and larger capacity for patient education and fixation videos
• 20% lighter in weight
|MARCO | 800.874.5274 | Marco.com|
|• Charts: Snellen, English, numeral, children, mask (horizontal, vertical, single optotype), specialty testing charts (separate red/green), Amsler grid, red/green 3D, ETDRS, test for phorias, charts for astigmatic testing
• Comfortable, user-friendly remote control
• Multiple levels of contrast sensitivity testing
• Animation video for pediatric fixation
• Patient education images
• Randomization function helps prevent letter/character memorization
|REICHERT TECHNOLOGIES | 716.686.4500 | Reichert.com|
|ClearChart 4 Digital
|• All-in-one system
• Optotypes include 17-letter set, eight-letter set, Sloan, HOTV, Landolt C, Landolt C and O, Tumbling E, and children’s optotypes
• Special test charts: astigmatic testing, fusion, phoria, and binocular balance
• Optotypes can be isolated, increased or decreased in size, and displayed in LogMar, Snellen, or linear progression
• 24-inch, high-resolution, LED backlit displays
• Intuitive user interface that can be controlled by the Phoroptor VRx Digital Refraction System or SightChek digital phoroptor, or by an infrared remote
|• Same features as ClearChart 4, plus ETDRS, contrast sensitivity, and patient education slides
• Lets users import images and videos from USB drive
|• Same features as ClearChart 4X, plus a linear polarized screen that has polarization angles of 45° and 135° and uses articulating mount to provide proper viewing for stereo testing
• Additional polarized charts are available
|VEATCH OPHTHALMIC INSTRUMENTS | 800.447.7511 | VeatchInstruments.com|
|• All-inclusive unit with blue tooth capabilities
• Standard optotypes and updated pediatric optotypes
• Slide images available
|Insight System||• Guided by Android device, so no software to be replaced
• Lets you add images and videos using SD Card
• Simplified remote for easier navigation
• Built-in contrast sensitivity