Topic

#Imaging

17 articles
  1. Articles 21 May 2023 9 min read

    Seven Important OCT Signs in CNVM

    1. Type of macular neovascularisation (MNV): Macular neovascularisation (MNV) is a broad disease entity characterised by the development of the abnormal vessels arising either from the retinal vasculature (deep capillary plexus) or choroidal vasculature (choriocapillaris). Choroidal neovascular membrane (CNVM) is a subtype of MNV, characterised by the abnormal growths of blood vessels from the choroidal capillaries that penetrate the retina, specifically into the sub-RPE and subretinal spaces. These vessels are extremely immature and extremely fragile, so they bleed and leak, de-structuring the macula, causing severe visual impairment. The classification of MNV is depicted below in Figure 1: Figure 1: A simple classification of macular neovascularisation (MNV): 2. Cause of CNVM: A CNVM is primarily classified based on the etiology into two categories: A) Age-related Macular Degeneration (AMD) associated CNVM and B) Non-AMD associated CNVMs. Causes of non-AMD associated CNVMs: Central s

    Dr. Ramesh Venkatesh · FVRF (Sankara Nethralaya) · +2 others
  2. Students Gallery 1 May 2021 7 min read

    i-File: Commotio Retinae

    Chief Complaint: A 12-year-old boy presented with redness and a decrease in vision in the left eye within four hours of injury with a top. History of Present Illness: Redness and decrease in vision in the left eye. No other significant complaint. Past Ocular History: No H/O any previous injury. Past Medical History/ History of Medication: No significant ocular past history for which he has used medications. Family History: No significant family history. Review of Systems/Systemic Examination The child was conscious, well oriented in time and space, afebrile, pulse rate was 88/min, respiratory rate was 16/minute. Examination of other systems were normal. Ocular Examination Best Corrected Visual Acuity (Snellen) Right eye (OD): 6/6 Left eye (OS): 6/36 with pinhole – 6/18p Ocular Motility/Alignment Extraocular motility was full and free in all gazes in both eyes. Intraocular Pressure (IOP)- By Applanation tonometry Right eye: 14mm Left eye: 16mm Pupils: Right eye - round and briskly react

    Dr. Priya Rasipuram Chandrasekaran
  3. Students Gallery 12 Apr 2021 3 min read

    i-File: Idiopathic Juxtafoveal Retinal Telangiectasia

    Question A 61-year-old presented with OU diminution of vision. He complains of distortion of letters which he has noticed in the last few months. He is a well-controlled diabetic for 13 years. There are no other systemic issues. Examination revealed a BCVA of OD 6/18(P) N8, OS 6/24 N8. The anterior segment is unremarkable except for pseudophakia OU (no e/o PCO). Fundus and FFA as shown What is the most probable diagnosis (give your differential)? Which other investigation will help in the diagnosis How will you treat the patient? Answer: Idiopathic Juxtafoveal Retinal Telangiectasia(IJRT) Classification COATS Subretinal exudation without vascular abnormalities Subretinal exudation with vascular abnormalities Exudation with AV malformation This classification is mostly for interest and not followed anymore GASS and BLODI ( 1993) This classification was a modification of the original Gass and Oyakawa classification of 1982 1A) Congenital in nature, having a UNILATERAL presentation in MAL

    Dr. Bikramjit Pal
  4. Articles 2 Apr 2021 11 min read

    Newer Imaging Technology in Glaucoma

    Clinical examination of the disc has been the basis of disc and nerve fibre layer evaluation for ages but it is marred by its subjectivity and non-reproducibility, in the diagnosis and detection of glaucoma. Though visual field changes give concrete and reproducible evidence of glaucomatous changes, it becomes manifest only after considerable damage has occurred to the retinal ganglion cells(RGCs) and the nerve fibre layer(NFL). There are normally 1.2 - 2.4 million nerve fibres and corresponding number of ganglion cells in the retina. Kerrigan-Baumann and Quigley et al 1 documented that a loss of 35.7% of the RGCs was required for the manifestation of corrected pattern standard deviation(CPSD) 90 seconds per eye Figure4: Print out of a normal C20 programme Threshold program (N20 and N30): This program uses more contrast levels to search for the patient's threshold at each of the tested location. N30- horizontal area extended to include an extra portion of the nasal visual field, result

    Prof. Sushmita Kaushik · Dr. SS Pandav
  5. Articles 2 Apr 2021 14 min read

    Advances in Retinal Imaging

    Modern imaging modalities in the field of the retina have expanded our understanding of common pathologies including diabetic retinopathy (DR), age-related macular degeneration (AMD), central serous chorioretinopathy (CSCR), and many rare retinal diseases such as dystrophies, which were poorly understood before. This chapter describes newer emerging techniques in retinal imaging which enables advanced screening, monitoring and provide objective measures for treatment monitoring. MULTICOLOUR IMAGING Compared to standard fundus cameras, multi-colour images produced by the scanning laser ophthalmoscope(SLO) have a higher resolution due to reduced light scatter and allow image acquisition at different planes and higher contrast through a non mydriatic pupil using different wavelengths. SPECTRALIS Optical Coherence Tomography SDOCT(SPECTRALIS SD-OCT, Heidelberg Engineering,Heidelberg, Germany) uses the confocal scanning laser ophthalmoscope(cSLO) to capture three simultaneous reflectance im

    Dr. Sushma J · Dr. Jay Chhablani
  6. Articles 2 Apr 2021 12 min read

    Eales Disease: Current Concepts in Etiopathogenesis and Management

    Introduction Eales’ disease is an idiopathic retinal periphlebitis that primarily affects the peripheral retina in young adults. Eales’ disease was first described by Henry Eales, a British ophthalmologist, in 1880 and 1882.1,2 He found it in seven young, male patients ranging in age from 14 to 29 years with recurrent vitreous hemorrhage. In addition, these patients had history of headache, variation in peripheral circulation, chronic constipation and epistaxis. In the next century, the disease was redefined by several investigators. 3-6 Elliot first recognized the inflammation of retinal vein and described it as periphlebitis retinae.4 Subsequently several investigators documented both venular and arteriolar inflammation.5,7 Eales’ disease most commonly affects healthy young adult males and is an important cause of preventable blindness in young adults. The predominant age of onset of symptoms is 20-30 years. The disease is more commonly seen in the Indian subcontinent. However, it ha

    Sandeep Saxena, M.S., MAMS
  7. Articles 2 Apr 2021 28 min read

    Optical Coherence Tomography- Evolution and Clinical Applications

    1. Introduction Optical coherence tomography (OCT) is a noninvasive imaging modality that has revolutionized the practice of clinical ophthalmology over the past decade. OCT provides high-resolution cross-sectional images of the retina, optic nerve head and retinal nerve fibre layer (RNFL) unobtainable by any other current modality, and enables qualitative and quantitative evaluation. As opposed to other retinal imaging modalities that provide én face images, it provides for sectional information, and in that sense is analogous to an in vivo “optical biopsy” (Figure 1). It is safe, fast, reproducible, does not require greatly skilled technicians, and has minimal, if any, interobserver issues. Several advances in recent times have contributed to vast improvements in resolution and speed of OCT devices, and expanded their applications manifold. In 2010, in the US alone, an estimated 16 million OCT procedures were done, amounting to $ 780 million in reimbursement.[1] Fig 1. Macular OCT wi

    Dr. Abhishek R. Kothari
  8. Articles 2 Apr 2021 7 min read

    Choroidal Neovascular Membrane

    Choroidal neovascular membrane (CNVM) is an ingrowth of new vessels from the choriocapillaris through a break in the outer aspect of Bruch’s membrane into the sub-pigment epithelial space. These new vessels are accompanied by fibroblasts, resulting in a fibrovascular complex that proliferates within the inner aspect of Bruch’s membrane. This fibrovascular complex can disrupt and destroy the normal architecture of the choriocapillaris, Bruch’s membrane, and the RPE. In addition, fibroglial and fibrovascular tissue can also disrupt and destroy the normal architecture of the photoreceptors and the remaining outer retina leading to the formation of a disciform scar. Within the subpigment epithelial space, the CNV can leak fluid and blood and may be accompanied by a serous or hemorrhagic detachment of the RPE. CNVM that remains restricted to the sub-RPE space is Type1 CNVM and when it becomes sub-retinal it is Type 2 CNVM. Clinical Features Symptoms of CNVM: Sudden onset of decreased vision

    Dr. Thomas Thachil
  9. Interesting Reads 1 Apr 2021 19 min read

    Understanding Retinal Imaging : What Lies Ahead of Us?

    “Be careful, now that I can see the Inner You.” -Imaging modalities today Retinal imaging has come a long way today. From times of appropriately concentrating the fluorescein dye from scratch in the lab itself to times where we have a dye free angiography system, technology has covered vast boundaries. There is a platter of different modalities in the market today, each having their own ebb and flow. And what the future beholds for us is certainly inexplicable. To throw a light on these modalities, we have a special interview with someone who continues to extensively work on these technologies and modalities day in and out, Dr Muna Bhende. Dr. Muna Bhende is a senior consultant and deputy director of Shri Bhagwan Mahavir VR Services, Medical research foundation, Sankara Nethralaya, Chennai. eOphtha: There is a wide discussion on OCT Angiography (OCT-A) replacing FFA in the field of the medical retina in the near future. What is your take on that? How do you compare the clinical output

    Dr. Dhaivat Shah
  10. Articles 1 Apr 2021 26 min read

    Optical Coherence Tomography

    Introduction Optical Coherence Tomography is a powerful noninvasive imaging modality that performs high resolution, micron-scale, cross-sectional imaging of the retina. Originally developed in 1991 by Huang et al, [1] OCT technology has continually evolved and expanded within ophthalmology and has been explored in a wide range of clinical applications. With the introduction of Spectral/ Fourier Domain OCT (SD-OCT, FD-OCT) and Swept Source OCT (SS-OCT), there is greater tissue resolving power, significantly higher scan density, and faster data acquisition than original Time Domain OCT. Thus, OCT has revolutionized the practice of ophthalmology and, in particular the diagnosis and management of patients with retinal disease. This chapter describes the basics of OCT technology and its clinical applications in retinal disorders. OCT technology and working principle [2-8] OCTs operate on the principle of indirect low-coherence interferometry, in which a beam of light is directed into the re

    Dr. Remya Paulose · Dr. Jay Chhablani

Other topics

Review Vitreoretina Top Ten Series Tips & Pearls Made Easy Macular Diseases Cornea and External Eye Diseases Must Read Preferred Practise Pattern Learn from Masters Treatment Uvea and Intraocular Inflammation Case Discussion Cataract Surgery i-File Pediatric Ophthalmology Glaucoma Grand Rounds infection