Ultrahigh Resolution Optical Coherence Tomography (UHR-OCT)
Ultrahigh resolution optical coherence tomography (UHR-OCT) is an advanced imaging technique that provides microscopic-level visualization of tissue structures by using broadband light sources to achieve axial resolutions significantly better than standard OCT systems. Key features of UHR-OCT include:
Improved Axial Resolution
- Axial resolution is improved by an order of magnitude, from 10-15 μm to the sub-μm range. [1]
- Enables superior visualization of tissue microstructure compared to standard OCT. [3]
- Allows identification and quantitative measurement of retinal layers. [2]
Broadband Light Sources
- Uses ultrashort pulse laser sources like Ti:sapphire lasers with very broad spectral bandwidths. [2]
- Enables axial resolutions of 2-3 μm in the retina and 2 μm in the cornea. [2]
Applications in Ophthalmology
- Enables visualization of foveal and optic disc contour, as well as internal retinal and choroidal architecture. [3]
- Potential for imaging corneal microstructure for monitoring and control of kerato-refractive surgery. [2]
- Allows tracking of disease progression in animal models without sacrificing the animal. [3]
- Improves understanding of pathologies and enables earlier diagnosis and treatment of ocular diseases. [2]
Which Can it Help Diagnose with Lyme Disease?
UHR-OCT (Ultra High-Resolution Optical Coherence Tomography) is a valuable diagnostic tool for various ocular manifestations associated with Lyme disease. Below is a detailed analysis of how UHR-OCT can assist in diagnosing specific conditions related to different stages of Lyme disease, along with definitions of each condition, including terms that may be less familiar.
Stage 1 Lyme Disease
Definition
Stage 1 Lyme disease, or early localized Lyme disease, typically presents with symptoms such as erythema migrans (a characteristic rash), headache, stiff neck, and nausea. These symptoms arise within 1 to 28 days following a tick bite.
Ophthalmic Manifestations
1. Conjunctivitis: Inflammation of the conjunctiva, the membrane covering the white part of the eye and the inner eyelids. UHR-OCT can help assess the severity of conjunctival involvement but is not typically used as a primary diagnostic tool for conjunctivitis.
2. Photophobia: Sensitivity to light, which can occur due to inflammation of the eye. UHR-OCT can be useful in evaluating any underlying retinal or optic nerve issues that may contribute to photophobia, although it does not directly diagnose the condition itself.
Stage 2 Lyme Disease
Definition
Stage 2 Lyme disease, or early disseminated Lyme disease, may occur weeks to months after the initial tick bite. It can lead to more severe neurological symptoms, including meningitis, and may affect the eyes.
Ophthalmic Manifestations
1. Iridocyclitis: Inflammation of the iris (the colored part of the eye) and the ciliary body (the structure that produces aqueous humor). UHR-OCT can help visualize the anterior segment and assess the extent of inflammation.
2. Uveitis: Inflammation of the uveal tract, which includes the iris, ciliary body, and choroid. UHR-OCT is beneficial for diagnosing and monitoring uveitis by providing detailed images of the retinal structure.
3. Vitritis: Inflammation of the vitreous body, the gel-like substance filling the eye. UHR-OCT can detect changes in the vitreous and help assess the degree of inflammation.
4. Pars planitis: A type of intermediate uveitis affecting the pars plana region of the eye, located between the iris and the retina. UHR-OCT can assist in visualizing the retinal layers and any associated changes.
5. Diplegia: Paralysis affecting symmetrical parts of the body, often due to neurological involvement. UHR-OCT does not diagnose diplegia directly but can help assess any optic nerve involvement.
6. Painful radiculopathy: Nerve root pain that can occur with Lyme disease. UHR-OCT is not used for diagnosing radiculopathy but can evaluate any related ocular symptoms.
7. Choroiditis: Inflammation of the choroid, a layer of blood vessels and connective tissue between the retina and the sclera (the white part of the eye). UHR-OCT can visualize the choroidal structure and assess for inflammation.
8. Macular edema: Swelling in the macula, the central part of the retina responsible for sharp vision. UHR-OCT is particularly effective in diagnosing and monitoring macular edema.
9. Optic disc edema: Swelling of the optic disc, the point where the optic nerve enters the eye. UHR-OCT can help visualize the optic nerve head and assess for edema.
10. Optic disc pallor: Indicates damage to the optic nerve, often seen in conditions like glaucoma or optic neuritis. UHR-OCT can aid in evaluating the optic nerve head for signs of atrophy.
a. Anterior Ischemic Optic Neuropathy (AION): A condition characterized by sudden vision loss due to insufficient blood flow to the optic nerve. UHR-OCT can help assess the optic nerve head and detect changes associated with AION.
b. Optic neuritis: Inflammation of the optic nerve, often leading to vision loss. UHR-OCT is useful for evaluating the nerve fiber layer and detecting inflammation.
c. Neuroretinitis: Involves inflammation of the retina and optic nerve. UHR-OCT can assist in visualizing the retinal layers and any associated edema.
Stage 3 Lyme Disease
Definition
Stage 3 Lyme disease, or late disseminated Lyme disease, can occur months or years after the initial infection and may lead to chronic symptoms, including neurological issues.
Ophthalmic Manifestations
1. Stromal keratitis: Inflammation of the corneal stroma (the thick, transparent layer of tissue in the cornea). UHR-OCT can be used to assess corneal thickness and detect any inflammatory changes.
2. Episcleritis: Inflammation of the episclera, the thin layer of tissue covering the sclera. UHR-OCT is not typically used for diagnosing episcleritis but can help assess any associated ocular surface changes.
3. Orbital myositis: Inflammation of the eye muscles. UHR-OCT can assist in visualizing muscle involvement but is not the primary diagnostic tool.
In summary, UHR-OCT can significantly aid in diagnosing and monitoring various ocular manifestations of Lyme disease, particularly in stages 2 and 3. However, its role in diagnosing early-stage manifestations is limited, and other clinical assessments and tests are often necessary for a comprehensive diagnosis. Understanding terms like choroid—the vascular layer of the eye that provides nourishment to the retina—can enhance comprehension of the ocular complications associated with Lyme disease.
Challenges and Limitations
- Requires special care to balance optical dispersion in the interferometer. [3]
- Chromatic aberration in the eye poses a fundamental limit to transverse resolution. [3]
- Scattering in deeper structures like the RPE and choroid can degrade transverse resolution. [2]
- Availability depends on development of compact and affordable broadband light sources. [3]
UHR-OCT Manufacturers in the USA
- Bioptigen Inc. (Research Triangle Park, North Carolina)
- Produces the Bioptigen SD-OCT system with an axial resolution of about 3 μm. [2]
- Optopol Technology SA (Zawiercie, Poland)
- Manufactures the Copernicus HR SOCT system with 3 μm axial resolution, sold in the USA. [2]
- Thorlabs (Newton, New Jersey)
- Provides components for custom-built UHR-OCT systems, such as galvanometric scanning mirrors, lenses, and superluminescent diode light sources. [1]
UHR-OCT Ophthalmologists in California
- University of California, Davis
- Researchers have developed a high-speed, extended-range UHR SD-OCT system using a broadband superluminescent diode light source. [3]
- Stanford University School of Medicine (Stanford, California)
- Home to the Byers Eye Institute, which likely has access to advanced UHR-OCT imaging for research and clinical applications. [3]
- Doheny Eye Institute at UCLA
- Likely has access to UHR-OCT imaging capabilities. [2]
- USC Roski Eye Institute
- Another institution in California that may utilize UHR-OCT technology. [3]
- UC San Francisco Department of Ophthalmology
- Also likely to have UHR-OCT imaging capabilities. [2]
In summary, UHR-OCT is a powerful research and clinical tool in ophthalmology that enables unprecedented visualization of microscopic tissue features. Continued advancements in light sources and imaging techniques will further expand its capabilities and applications.
Read More
[1] https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9045918/
[2] https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3934962/
[3] https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7414734/
[4] https://gandh.com/optical-coherence-tomography
[5] https://www.pharmaexcipients.com/news/thin-multilayered-coatings/
[6] https://www.dkphotonics.com/fiber-optic-components-for-optical-coherence-tomography-applications.html
[7] https://link.springer.com/referenceworkentry/10.1007/978-3-319-06419-2_10
[8] https://www.ncbi.nlm.nih.gov/pmc/articles/PMC1950821/
[9] https://dictionary.cambridge.org/dictionary/english/choroid
[10] https://en.wikipedia.org/wiki/Choroid
[11] https://medlineplus.gov/ency/article/002318.htm
[12] https://www.merriam-webster.com/dictionary/choroid
[13] https://eyewiki.org/Lyme_Disease
[14] https://www.aao.org/education/current-insight/ocular-involvement-in-lyme-disease
[15] https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5426134/
[16] https://www.ncbi.nlm.nih.gov/books/NBK431066/