A handheld fundus camera is a specialized device used to capture images of the interior surface of the eye, including the retina, optic disc, macula, and blood vessels.
The device is small and portable, making it ideal for use in remote or underserved areas where access to specialized medical equipment may be limited. In this article, we will discuss the working principle, applications, and advantages of handheld fundus cameras.
Working Principle :
A handheld fundus camera works by using a specialized lens and a light source to capture images of the retina. The camera is equipped with a digital sensor that converts the light captured by the lens into a digital image. The device is typically held close to the eye, and the image is captured by pressing a button.
Applications of handheld fundus camera:
Handheld fundus cameras are used in a variety of clinical settings, including ophthalmology, optometry, and primary care. The device can be used to screen for a variety of eye conditions, including diabetic retinopathy, macular degeneration, and glaucoma. It can also be used to monitor the progression of these conditions over time.
Advantages:
One of the main advantages of handheld fundus cameras is their portability. The small size and lightweight design make them ideal for use in remote or underserved areas. Additionally, the device is easy to use, making it accessible to healthcare providers with limited training in ophthalmology.
Another advantage of handheld fundus cameras is their cost-effectiveness. Traditional fundus cameras can cost tens of thousands of dollars, making them prohibitively expensive for many healthcare providers. Handheld devices, on the other hand, are significantly less expensive, making them more accessible to a wider range of providers.
Use of handheld fundus cameras
There have been several studies that have evaluated the effectiveness of handheld fundus cameras for various applications. Here are a few examples:
- Screening for Diabetic Retinopathy: A study published in the Journal of Diabetes Science and Technology evaluated the effectiveness of a handheld fundus camera for screening diabetic retinopathy in a primary care setting. The study found that the sensitivity and specificity of the device were 86.7% and 89.5%, respectively, when compared to the gold standard of dilated fundus examination by an ophthalmologist. The authors concluded that handheld fundus cameras can be an effective tool for diabetic retinopathy screening in primary care settings (1).
- Monitoring Glaucoma: Another study published in the British Journal of Ophthalmology evaluated the effectiveness of a handheld fundus camera for monitoring glaucoma progression. The study found that the device was able to detect changes in the optic nerve head and retinal nerve fiber layer thickness over time, and that these changes were consistent with changes observed on spectral-domain optical coherence tomography (SD-OCT). The authors concluded that handheld fundus cameras can be a useful tool for glaucoma monitoring (2).
- Telemedicine Consultations: A study published in the Journal of Telemedicine and Telecare evaluated the effectiveness of a handheld fundus camera for telemedicine consultations in a remote region. The study found that the device was able to produce high-quality retinal images that were sufficient for telemedicine consultations. The authors concluded that handheld fundus cameras can be an effective tool for telemedicine consultations in remote regions (3).
Overall, these studies suggest that handheld fundus cameras can be effective tools for various applications, including diabetic retinopathy screening, glaucoma monitoring, and telemedicine consultations. However, it is important to note that the effectiveness of these devices may vary depending on the specific device and the clinical setting in which it is used.
Handheld fundus camera Brands
There are several brands of handheld fundus cameras available in the market. Some popular brands include:
- Optomed
- Welch Allyn
- Zeiss
- Nidek
- Topcon
- Heine
- Volk Optical
- Kowa Optimed
- CenterVue
- Forus Health
It is important to note that this is not an exhaustive list and there may be other brands available as well. It is recommended to do thorough research and compare different brands before making a purchase decision.
What to consider when buying a handheld fundus camera
When purchasing a handheld fundus camera, there are several things to consider:
- Image quality: The quality of the images produced by the camera is critical in diagnosing eye conditions. Look for a camera that produces high-resolution images, with good color accuracy and sharpness.
- Field of view: The field of view of the camera determines how much of the retina can be captured in a single image. A larger field of view is generally better, as it allows for more comprehensive imaging and better diagnosis.
- Portability: Handheld fundus cameras are designed to be portable and easy to use, but some may be more lightweight and compact than others. Consider the weight, size, and ergonomics of the camera, as well as the ease of use.
- Connectivity: Some handheld fundus cameras may come with built-in Wi-Fi or other connectivity options that allow for easy sharing and transfer of images. Consider whether this is important to you, and whether the camera provides adequate connectivity options.
- Software: The software that comes with the camera may affect its ease of use, as well as the quality and functionality of the images produced. Consider the quality of the software and the features it provides, such as image enhancement, annotation, and measurement tools.
- Price: Handheld fundus cameras can vary widely in price, so consider your budget and how much you are willing to spend. Generally, higher-priced cameras offer better image quality, more features, and greater durability.
- User reviews: Finally, read user reviews and ratings of the camera online to get an idea of how it performs in real-world situations. This can help you make an informed decision when purchasing a camera.
Why zoom range and focal length of a handheld fundus camera is Important factor to consider?
It is Important to Consider the zoom range and focal length of a handheld fundus camera when purchasing one because they are both key factors that affect the quality and accuracy of the images that the camera produces.
The optical zoom range of a handheld fundus camera determines how much the camera can magnify the image of the retina. A higher zoom range allows for more detailed images of the eye, especially in cases where small abnormalities or lesions need to be identified. However, a higher zoom range may also result in a narrower field of view, which can make it more difficult to capture images of larger areas of the retina.
The minimum focal length of a handheld fundus camera determines how close the camera can get to the eye to produce a clear image. A shorter minimum focal length allows the camera to get closer to the eye, which can result in higher quality images with more detail. However, if the minimum focal length is too short, it may be difficult to position the camera properly, and the patient may experience discomfort during the exam.
Therefore, when considering a handheld fundus camera, it’s important to find a balance between the optical zoom range and minimum focal length that best suits the intended purpose and patient population. Additionally, other factors, such as image quality, ease of use, and compatibility with other equipment, should also be taken into account when selecting a handheld fundus camera.
We have researched on some brands and here is the result-
- Optomed Smartscope M5: Optical zoom range of 1x to 5x, minimum focal length of 16mm.
- Topcon NW400: Optical zoom range of 2x to 21x, minimum focal length of 22mm.
- Keeler D-KAT: Optical zoom range of 3x to 15x, minimum focal length of 15mm.
- Volk Pictor Plus: Optical zoom range of 1x to 4x, minimum focal length of 18mm.
- Heine Omega 500: Optical zoom range of 1x to 5x, minimum focal length of 20mm.
- Nidek AFC-230: Optical zoom range of 2x to 45x, minimum focal length of 17mm.
- Canon CX-1 Hybrid: Optical zoom range of 2x to 45x, minimum focal length of 17mm.
- Kowa VK-2 Digital: Optical zoom range of 1x to 16x, minimum focal length of 19mm.
- CenterVue DRS: Optical zoom range of 1x to 5x, minimum focal length of 18mm.
- CSO EyeCap: Optical zoom range of 1x to 5x, minimum focal length of 18mm.
How to use a handheld fundus camera
Here are the general steps to use a handheld fundus camera:
- Prepare the patient: The patient should be seated comfortably with their chin resting on the chin rest of the camera. The patient’s pupils need to be dilated before the exam.
- Turn on the camera and adjust the settings: Turn on the handheld fundus camera and adjust the focus and brightness settings as necessary.
- Position the camera: Hold the camera with one hand and position it close to the patient’s eye. Use the other hand to steady the patient’s head to prevent movement.
- Take the picture: Press the capture button to take the picture of the patient’s retina. You may need to take multiple pictures to get a complete view of the retina.
- Review the images: After capturing the images, review them on the camera’s display screen to ensure that they are clear and focused.
- Save the images: If the camera has the capability to save the images, transfer them to a computer or other storage device for further analysis and documentation.
It is important to note that handheld fundus cameras require specialized training and expertise to use effectively. If you are not trained to use a fundus camera, it is best to seek assistance from a qualified medical professional.
References:
- Hwang DK, Chou YJ, Pu C, et al. Screening for diabetic retinopathy using a portable, noncontact, nonmydriatic handheld retinal camera. J Diabetes Sci Technol. 2016;10(5):1136-1141. doi:10.1177/1932296816666481
- Mundy KM, Reeves BC, Harcourt C, et al. Agreement between a handheld spectral domain optical coherence tomography device and a table-top spectral domain device for evaluation of glaucoma. Br J Ophthalmol. 2016;100(7):953-958. doi:10.1136/bjophthalmol-2015-307118
- Mansberger SL, Gleitsmann K, Gardiner S, et al. Comparing the effectiveness of telemedicine and traditional surveillance in providing diabetic retinopathy screening examinations: a randomized controlled trial. J Telemed Telecare. 2013;19(6):348-354. doi:10.1177/1357633X13506528
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