Introduction:
Diabetes is a chronic condition affecting many individuals worldwide. It can cause damage to various body parts, such as kidneys, eyes, heart, and brain. Diabetic eye disease remains a main cause of eyesight loss, affecting millions worldwide. Diagnosing such conditions early and taking timely intervention to manage them effectively is pivotal. Ophthalmic imaging plays an important role in diagnosing and managing diabetic eye disease. Many advancements in the field of ocular imaging technology have made it possible to provide optimal treatment for individuals with diabetic eye disorders.
What Is Diabetic Eye Disease?
Diabetes can cause damage to various parts of the body, including the eyes. Diabetes eye diseases are called eye problems that can occur in individuals with diabetes. Over time, diabetes can damage the eyes, leading to impairment of vision or even blindness. Diabetic eye disease includes:
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Diabetic Retinopathy - In this condition, abnormal new blood vessel formation occurs on the retina's surface.
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Diabetic Macular Edema - In this eye condition, fluid builds up on the retina, leading to swelling and poor vision. In severe situations, permanent vision loss can even occur.
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Cataract - It is a clouding of the lens of the eye, which is generally transparent. High blood sugar levels can lead to cataracts.
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Glaucoma - Optic nerve damage occurs due to excess pressure buildup in the eyes. This damage can lead to irreversible loss of vision.
What Ophthalmic Imaging Are Used for Diabetic Eye Disease?
1) Fundus Photography:
Fundus photography is the imaging technique used to take multiple photographs of the eye's interior. A fundus camera, a specialized microscope attached to a camera, is used to examine the eye structures such as the retina, optic disc, and lens. Fundus photography is a significant imaging technique for evaluating diabetic retinopathy. With the help of high-resolution images of the retina taken by fundus photography, the presence and severity of retinal abnormalities such as hemorrhages, exudates, microaneurysms, and neovascularization can be checked. Traditionally, fundus cameras clicked two-dimensional images of the retina. However, recent advancements in digital imaging have developed wide-field fundus photography systems, providing a wide view of the retina in a single image.
2) Optical Coherence Tomography (OCT):
Optical coherence tomography is a noninvasive imaging technique used to photograph the innermost part of the eyes, called the retina. This imaging technique has revolutionized how eye care specialists evaluate and treat diabetic macular edema and other complications of diabetes. This imaging technique provides high-resolution, cross-sectional visuals of retinal layers, so it helps calculate the macular thickness, its shape, and the presence of intraretinal fluid.
Spectral-domain OCT (SD-OCT) and swept-source OCT (SS-OCT) are the two types of OCT imaging techniques. SD-OCT offers excellent image resolution and is the gold standard for monitoring diabetic retinopathy and maculopathy. SS-OCT provides deeper penetration and faster image acquisition, making it useful in thickened posterior hyaloid or vitreomacular traction cases in diabetic patients.
3) Optical Coherence Tomography Angiography (OCTA) -
OCTA is the most recent innovation in ocular imaging. It provides clear imaging of the retinal vasculature in different depths, such as the choriocapillaris and the middle and deep vascular plexus. It provides detailed information about microvascular changes and retinal perfusion in diabetic retinopathy. OCTA is dyeless imaging, so it is safe from allergies that occur due to the injection of fluorescein dye.
It is a valuable diagnostic tool for the early detection of capillary dropout, neovascularization, and macular ischemia. More research and studies are being conducted on OCTA; however, significant progress has already been made in diagnosing many retinal vascular diseases, such as diabetic retinopathy.
4) Fluorescein Angiography (FA)
Fluorescein angiography is an imaging test used to visualize the retina's blood vessels. During this test, a healthcare provider will inject a fluorescein dye through a vein in the arm. This dye reaches the blood vessels in the eye and highlights the eyes' blood vessels. This allows the provider to see the blood vessels. This test is crucial in evaluating diabetic retinopathy and diabetic macular edema. It provides details about retinal perfusion and vascular leakage. However, this test has some side effects, like allergic reactions to the dye used, slight yellowish skin discoloration, and a burning sensation if the dye leaks during the injection.
5) Ultrawide-Field Imaging
Ultrawide-field imaging effectively provides incredible retina and retinal periphery visuals, even in individuals with small pupils. Generally, ultrawide-field imaging with fluorescein angiography is combined to provide unparalleled visualization of every part, from the deeper part of the eye to the periphery. This allows eye care specialists to evaluate peripheral capillary nonperfusion or neovascularization. In the future of teleophthalmology screening for diabetic eye disease, ultrawide-field imaging will play a pivotal role. Many renowned companies have announced the development of artificial intelligence technologies for detecting retinal disorders based on ultrawide-field retinal images.
6) Multimodal Imaging:
Multimodal imaging means the simultaneous production of signals for multiple imaging techniques. This technique has emerged as a powerful diagnostic tool in evaluating diabetic eye disease. This technique combines the strengths of various imaging techniques, such as fundus photography, OCT, OCT-A, and FA; multimodal imaging enables detailed checking of various eye pasts, their function, and blood flow. Furthermore, this technique has made it possible to overlay and correlate information from various imaging modalities, creating a more detailed understanding of diabetic retinopathy.
Conclusion:
Ophthalmic imaging of diabetic eye disease plays a significant role in diagnosing, monitoring, and managing diabetic-related eye disorders like diabetic retinopathy, diabetic macular edema, cataracts, and glaucoma. Ophthalmic imaging is evolving from traditional fundus photography to advanced OCT and OCT-A, providing eye care specialists with detailed information about eye structures, function, and blood flow. As technology advances, eyecare specialists are better equipped with various technologies and precise instruments to diagnose and treat diabetic eye disease effectively.
