This is the fifth part of a series of posts on comparing Welch Allyn products that will help incoming first year medical students learn about and select different medical instrument components to construct the right Welch Allyn diagnostic kit (otoscope and ophthalmoscope). The focus of this discussion is on Welch Allyn diagnostic kit ophthalmoscope heads.
This is the topic that will have the most options and provide the basis behind one of the larger price differences in your diagnostic kit. Ophthalmoscopes, as the name suggests, are instruments used to look at the eyes, specifically the retina. Some med students will get through all of medical school without learning how to actually perform an exam using their ophthalmoscope, let alone utilize many of the bells and whistles that come with it. As with otoscope heads, all of the below ophthalmoscopes are the 3.5 volt version, which refers to the standard power handles, and are in contrast to miniature “pocket sized” versions of these instruments. If you’re interested in the bottom-line short version, scroll to the bottom.
We’ll start as usual by reviewing the baseline model, seen right. This has the basics that any med student would want, and will allow for visualization of the retina. It feels and looks just like any other ophthalmoscope you would see in clinic, which means learning on this will prepare you for whatever you may find along medical school, with three additional filters you will most likely never use.
Aside from being able to change the light size or dim the light, this ophthalmoscope allows the user to change the light into a slit beam, for easier visualization of objects on the surface of the eye, as well as the depth of the anterior chamber. It also comes with a fixation aperture, which basically turns the light into cross hairs in case you want to double your ophthalmoscope as a sniper rifle scope. The actual reason for this configuration is for relative measurement and assessing blind spots. This feature is rarely used even by ophthalmologists, usually in the setting of hospital consultation when there are limited instruments. The final added feature is the red-free filter, which is a funny way of saying “green light” used to contrast structures in the back of the eye from the otherwise red background on which they reside. Again, chances are you won’t use any of these, and they won’t be taught in med school physical exam classes.
The key component that will be used and comes standard on these types of ophthalmoscopes are the focusing lenses, which allow the user to adjust for the physical size of the eye and focus on a crisp image at the back of the eye. This will come up in subsequent models.
Overall, this is the model of choice for the average med student looking to purchase a quality instrument without the markup associated with unneeded features. However, many retailers do not offer Welch Allyn diagnostic sets with this lower-priced option, even though such sets are manufactured.
The next step up is the coaxial ophthalmoscope, which is commonly one of the two models offered by retailers as an ophthalmoscope option in a Welch Allan diagnostic kit. Like the Standard Ophthalmoscope above, it has the same number of focusing lenses, and includes all of the above apertures, plus the cobalt filter. This is a blue light used in conjunction with fluorescein stain placed in the eye, which produces neon green or orange concentrations of the dye within scratches or irregularities on the surface of the eye. The idea is that it highlights lesions on a clear medium that are otherwise difficult to visualize. This is helpful in field work during emergencies, but will not be a needed skill to use as a medical student, or a necessary tool in the middle of an actual emergency room that has full slit lamps with this feature.
Welch Allyn claims, in their usual fashion, that this upscale model provides less glare, superior visibility, and a larger field of view compared to the standard ophthalmoscope. While bad or broken ophthalmoscopes are indeed a detriment to an ophthalmoscopic exam, I doubt anyone would be able to practically tell the difference between the coaxial and standard Welch Allyn ophthalmoscope.
For completeness, I will also mention that Welch Allyn manufactures the AutoStep Coaxial Ophthalmoscope, which is the exact same instrument, but with additional focusing lenses for super-fine tuning. This model is not offered in any Welch Allyn diagnostic kit, and would need to be purchased separately. However, as you can imagine, these additional focusing lenses are not a significant improvement and in no way recommended for medical students (or anyone else).
The final Welch Allyn Ophthalmoscope to review is the PanOptic Ophthalmoscope, also known as the bazookascope. As you can see from the image, this is in a different league as the other varieties, as its price tag will also prove. Like the above opthalmoscopes, the PanOptic also fits on any standard Welch Allyn 3.5 V power handle.
Welch Allyn states the advantages of this scope include a five-times greater view of the back of the eye, and 26% increased magnification. As mentioned in the otoscope review, an oddly specific 26% increase in magnification is unnoticeable. The PanOptic Ophthalmoscope does however provide a significantly larger view of the retina, with significantly less skill required to use the instrument compared to the learning curve of the above models. Simply holding this up to a patient’s eye will produce nice results. Less time spent figuring out how to use the instrument means more time dedicated to figuring out what you’re looking at. This is an underestimated double edged sword.
As long as a PanOptic is used, better visualization will be acquired. However the large majority of clinics and hospitals in this country do not have this expensive piece of equipment. It is exceedingly common for a medical student who learned on a Welch Allyn PanOptic to subsequently have no technical ability to use a standard ophthalmoscope in a practical setting, placing them at a severe disadvantage without their own instrument.
One of the main reasons med students purchase a diagnostic kit is to learn the technique of using these instruments, more so than to use them throughout (or after) medical school. Most clinics will provide med students with wall mounted versions of the standard ophthalmoscope, making it unnecessary to haul around a personal set. Due to the shape, these are also bulkier items that weigh down white coats and do not sit well in soft cases. Given all of the above, as well as the price below, it is exceedingly common for med students to attempt to sell their PanOptic ophthalmoscopes, finding them unnecessary. Nonetheless, some percentage of students will continue to purchase these instruments to ensure they have the best possible view of the back of the eye. This is one that definitely has its trade-offs.
In summary, the direct comparison is as follows:
|Cobalt Filter||Ease of Use||Exposure
||$170||No||Learning Curve||5 degrees|
||$190||Standard||Learning Curve||5 degrees|
|* prices are for the ophthalmoscope heads only. handles are sold separately.|
Prices are higher if you purchase components separately, so try to buy a value meal (a complete diagnostic kit sold as a single unit) unless you can find a really great deal. With that being said, the above three scopes were added to the price-check plugin as a reference.
Still can’t decide? Let us help! Check all that apply:
|My med school requires infrequent usage of diagnostic kits.|
|Money is of no concern in the purchase of my instruments.|
|I have a habit of losing things easily.|
|I want to learn physical exam techniques using equipment that will best prepare me for practical clinical settings.|
|I want to learn physical exam findings using the absolute best equipment at my disposal.|