{ optical coherence tomography machine }

  • Sudden blurring of vision could be a red alert for a systemic illness

    Exudative Retinal Detachment (ERD) is a lesion in which the neuroepithelial layer of the retina separates from the pigment epithelial layer without holes. The core mechanism is the destruction of the blood-retinal barrier or the imbalance of choroidal osmotic pressure, resulting in abnormal accumulation of plasma, lipids or blood in the subretinal space. Unlike rhegmatogenous or tractional detachment, ERD does not have retinal holes. ERD is often an "ocular crisis signal" of systemic or local diseases.


    Common causes:

    ERD is essentially the fundus manifestation of multi-system diseases, and its causes can be divided into two major categories:
    (1) Systemic diseases and pregnancy-related diseases: Severe preeclampsia (S-PE) and HELLP syndrome are high-risk factors for ERD; Hypertensive nephropathy: Malignant hypertension can cause choroidal circulation disorders, and fibrinoid necrosis of choroidal arteriole leads to a large amount of plasma exudation. (2) Ocular diseases such as uveitis and retinal vasculitis: Uveitis ranks first among the causes of ERD, especially posterior uveitis like VOGT-Koyanagi-Harada syndrome (VKH) and sympathetic ophthalmia. Inflammation leads to increased permeability of choroidal vessels, causing exudation. Tuberculous uveitis can form subretinal abscesses or granulomas, directly damaging the blood-retinal barrier. Vascular diseases: Coats' disease - Highly prevalent in children and adolescents. Retinal capillary dilation accompanied by a large amount of lipid exudation can lead to total detachment. Retinal vein occlusion (BRVO) - Ischemic vein occlusion induces the release of inflammatory factors, leading to vascular leakage; Tumors and congenital abnormalities: Choroidal melanoma or hemangioma disrupts the blood-retinal barrier, leading to the accumulation of exudate. Metastatic breast cancer and lung cancer are the most common primary foci. According to the latest study of EURETINA 2024, exudative detachment is the main manifestation of invasive retinopathy of prematurity (ROP), accompanied by edema in the anvascular area and subretinal exudation.


    Clinical manifestations:

    The symptoms of ERD patients are diverse, but there are usually four key warning signs:
    Painless vision loss: When the macular area is involved, vision can drop sharply to below 0.1. Unlike rhegmatogenous detachment, vision loss in ERD usually progresses more slowly, but patients in the acute phase of hypertensive crisis or VKH syndrome may lose central vision within a few hours. Visual distortion: Due to the displacement of photoreceptor cells caused by subretinal fluid, wavy distortion occurs when looking at straight lines. Amsler grid examination reveals typical grid distortion. Central dark spot: When the macular area is affected, a fixed black shadow appears in the center of the visual field, but the peripheral visual field remains relatively intact. Abnormal color vision and flashes: Inflammatory ERD (such as VOGT-Koyanagi-Harada disease) is prone to blue-yellow color vision shift.


    Diagnostic method:

    Multimodal imaging combined application of optical coherence tomography (OCT) : The gold standard for ERD diagnosis, which can directly display low-reflection dark areas of subretinal fluid and RPE detachment. EDI-OCT technology - enhanced penetration depth, can quantify choroidal thickness, and help distinguish VKH from CSC; Fluorescein angiography (FFA) : Active leakage foci show "ink-stained" or "chimney-like" hyperfluorescence (such as CNV); The bleeding area shows fluorescence occlusion, and the non-perfusion area suggests ischemic etiology. Indocyanine green angiography (ICGA) : Evaluation of choroidal vessels - Diagnosis of polypoid choroidal vasculopathy (PCV) or VKH complex; OCT angiography (OCTA) : Non-invasive detection of retinal/choroidal neovascularization and quantification of blood flow density; B-type ultrasound: When the refractive media is turbid, it shows subretinal fluid dark areas, differentiating choroidal tumors or hemorrhage. Multifocal electroretinography (mfERG) : Objectively assess retinal functional impairment, especially suitable for children or uncooperative patients;


    Treatment and prognosis:

    The treatment of ERD should focus on etiological therapy, supplemented by surgical intervention.

    Drug therapy: Glucocorticoids - systemic or topical application (such as intrauterine injection) to suppress inflammation (such as uveitis, Eales' disease); Anti-vegf drugs - reduce vascular leakage (such as BRVO, Coats' disease); Laser and photocoagulation therapy: Retinal laser photocoagulation - sealing abnormal blood vessels (Coats' disease, ischemic BRVO); Micro-pulse laser - Treating macular edema and reducing thermal damage; Surgical intervention: It is only used for complex cases, such as vitrectomy when Coats' disease is secondary to traction detachment. Spontaneous absorption is possible. After blood pressure is controlled in hypertensive choroidal lesions, the detachment can spontaneously return to its original position. The prognosis is highly dependent on the control of the primary disease: inflammatory ERD - early hormone therapy can completely reset it, and the visual recovery is relatively good; Tumors or Coats' disease - Delayed diagnosis and treatment can cause permanent photoreceptor damage. Amblyopia should be vigilant in children. Follow-up requirements - OCT and FFA should be reexamined every 3 to 6 months to monitor recurrence.



    Example 1: The retinal neuroepithelial layer in the macular area protrudes, with dark reflex cavities inside



    Example 2: A mass of hyperreflectivity can be seen in the central area, accompanied by subretinal effusion and shallow detachment of the retinal pigment epithelium layer

    Exudative retinal detachment is a "crisis signal" of systemic diseases within the eye, and its diagnosis and treatment require collaboration between ophthalmology and multiple disciplines. Early identification of the primary disease, combined multimodal imaging assessment, and targeted control of inflammation/vascular leakage are the core strategies to avoid permanent vision loss. Especially for premature infants and patients with chronic inflammation, regular fundus screening is a key line of defense for saving visual function!


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  • Have you got the OCT image of the fundus, are you still worrying about how to interpret it?

    Welcome to science time! This article will discuss optical coherence tomography (OCT), an advanced technology widely used in eye examination, and introduce the basic principles and sequence of OCT image reading to help people better understand this convenient and non-invasive ophthalmic examination tool. Have you got the OCT image of the fundus, are you still worrying about how to interpret it?

    Looking at the complex structure of the retina, are you still wondering where to start?

    optical coherence tomography

    OCT, or Optical coherence Tomography, is a technique that uses the principle of light reflection to make microscopic images. It has the advantages of non-invasive, simple, rapid and accurate, and has become an important tool for the study of various fundus diseases. The principle of OCT film reading is based on the difference in optical reflection between different microscopic tissues. When the light shines on the surface of the tissue, a part of the light will be reflected back, and the internal structure of the tissue can be analyzed by detecting the reflection. In OCT images, the level of reflectance can be represented by color or gray scale, forming a false color or gray scale map.

    optical coherence tomography

    When reading OCT, the following principles should be followed:
    1. Before analyzing the light reflection characteristics of the tissue, it is necessary to first determine the way (false color or gray scale) of the OCT film to indicate the level of reflection.

    2. Perform OCT image analysis in a certain sequence to ensure that no important information is missed.

    3. Through qualitative and quantitative analysis, find out the changes of morphological structure and explore the reasons for the changes.

    4. Combined with the patient's chief complaint, medical history, fundus color ultrasound, angiography and other examinations, the correct diagnosis was obtained after comprehensive evaluation.

    OCT image reading can be performed in the following steps: general outline → structure of retinal layers (see the figure below) → choroidal layer → measurement of relevant data, paying attention to the symmetry of both eyes → comprehensive analysis to give a diagnosis.
    The qualitative analysis includes morphological observation of the changes in the overall contour and structure of the retina, as well as based on reflexes
    Quantitative analysis mainly measures thickness, volume and area.


    Through the introduction of this article, I believe that everyone has a deeper understanding of the magic of OCT, let us look forward to the future development of OCT technology in the field of ophthalmology! Also welcome to contact us, we are Zhiding Medical Technology Co., Ltd.


    Tel : +86-137 3544 0201
    Email : sales@zd-med.com
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  • What are the features and benefits of Optical Coherence Tomography Luminor-D60?

    ZD Medical  new generation latest upgraded version of split OCT + anterior eye segment function

    Model: Optical Coherence Tomography Luminor-D60

    LSO technology is used for fundus imaging, which accurately helps you to identify retinal diseases, helps screening and reduce the leakage of diseases in the initial examination, and can greatly improve the efficiency of clinical use.


    The ZD Medical Optical Coherence Tomography Luminor-D60 is convenient, fast, clear, smooth and delicate. Equipped with professional analysis software, it makes OCT accurate and efficient in ophthalmic examination and analysis, and is a good helper for clinical diagnosis of fundus diseases.

    Optical Coherence Tomography

    Multiple functions:

    1. Macular analysis-Multiple scanning modes, high-definition imaging, binocular comparison and follow-up comparison are available.
    2. Glaucoma analysis - GCC thickness analysis and RNFL thickness analysis are available.
    3. Anterior eye segment diagnosis-Corneal structure is clearly visible, thickness of corneal layers can be measured manually or automatically, and atrial angle scanning is accurately aligned.



    Also welcome to contact us, we are ZD Medical Inc.

    Tel : +86-137 3544 0201
    Email : sales@zd-med.com
    Whatsapp/Mobile : +86-187 9586 9515