Topic

#Macular Diseases

38 articles
  1. Articles 2 Apr 2021 11 min read

    Retinopathy of Prematurity

    Introduction Retinopathy of Prematurity (ROP) is a fibrovascular proliferative disorder, which affects the developing peripheral retinal vasculature of premature infants. It is an avoidable cause of blindness in children. The initial signs of ROP are detectable by a few weeks after birth, and the condition progresses rapidly thereafter. This means that screening has to be timely, and there is only a very narrow window of opportunity for treating. If not treated, the condition progresses rapidly to Stage 4 or 5 in approximately 50% of babies. The visual prognosis for babies with Stage 5 disease (total retinal detachment) is very poor, even after complex vitreoretinal surgery. The primary goal of screening is to detect all babies with treatable disease in time for treatment to be effective. Pathogenesis In the normal foetus, vascular development of the retina occurs in two phases. Phase 1 (True vasculogenesis): It occurs from 8-21 weeks of foetal development. Spindle cells (mesenchymal p

    Parag K. Shah, DNB · Dr. V. Narendran, DNB · +1 other
  2. Articles 2 Apr 2021 8 min read

    Pan Retinal Photocoagulation (PRP), Focal Laser & Photodynamic Therapy (PDT) Technique & Tips.

    Introduction ‘LASER’ is acronym for “Light Amplification by Stimulated Emission Radiation.” This describes the emission process by which an intense beam of electromagnetic radiation is generated Basic Properties of Laser Always monochromatic (one wavelength) Collimated (all photons run parallel) & focused to a small point Coherent (always in same phase) Highest possible speed Physics Certain substances have property to lase i.e, absorb energy in one form & emit a new form of energy. On pumping these lasing substances electrons are transfered from a lower orbit to higher orbit (Bohr’s theory) Excited atoms in turn decay back to their original orbit of lower energy, emitting photons (packets of energy) This emission can be spontaneous or induced (stimulated) Photocoagulation (PHC) Photothermal reaction Temperature elevation 10 to 20 deg C Protein denaturation Pigment dependent Argon, krypton dye, diode, frequency double Nd Yag Tissue effects Induces moderate sterile inflammation- Creates

    Parag K. Shah, DNB · Dr. Varsha V. Prabhu · +1 other
  3. Articles 2 Apr 2021 35 min read

    Idiopathic Macular Hole

    Introduction Recent advances in the pathogenesis, classification, and surgical intervention of idiopathic macular holes have generated a renewed interest in this entity. Better indicators of the visual outcome, as well as refinements in the surgical technique, have led to improvements in the success of macular hole surgery. Clinical characterization and theories on the pathogenesis of macular hole have continued to evolve. Although originally thought to be the result of trauma, it is now recognized that most macular holes occur in the absence of antecedent injury and are referred to as idiopathic. Theories for the pathogenesis of idiopathic macular holes have included progressive thinning of the foveal tissue and pre hole cyst formation. The primary pathogenic role of the vitreous was suggested by studies that indicated a low relative risk for macular hole formation in eyes with complete posterior vitreous detachment. Gass proposed a theory whereby shrinkage of adherent cortical vitreo

    Sandeep Saxena, M.S., MAMS
  4. Articles 2 Apr 2021 55 min read

    Retinal vein occlusion

    Introduction Retinal vein occlusion (RVO) is the second most common retinal vascular disease to cause visual loss in adults after diabetic retinopathy. RVO has been classified into two main types, namely Central retinal vein occlusion (CRVO), Branch retinal vein occlusion (BRVO), the latter being more prevalent. Hemi-retinal vein occlusion has been classified separately since pathogenetically they are different as compared to the above two groups. In the following chapter a brief introduction to these variants of RVO, along with their epidemiology, clinicopathological profile, and treatment has been discussed. Epidemiology [1] The most recently published study summarizing 68,751 individuals from 15 studies, quoted that the prevalence of RVO was 5.20 per 1000 (for any form of RVO). The prevalence of BRVO alone was 4.42 per 1000 (95% CI 3.65–5.19) and that of CRVO was 0.80 per 1000. According to Hayreh et al, prevalence varied by ethnicity and increased with age, but do not differ by gen

    Dr. P. Mahesh Shanmugam · Divyansh Mishra · +1 other
  5. 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
  6. Articles 2 Apr 2021 8 min read

    Macular Buckle Indications, Technique and Challenges

    Macular Buckling (MB) is simply defined as a modified scleral buckle (SB) surgery where the sclera is remodeled to appose the retina to the sclero-choroidal complex thereby relieving the traction. Unlike conventional SB, where buckle element is placed circumferentially around the eyeball, MB element is placed behind the globe under macula indenting the sclera from posterior. MB has been tried by various surgeons for varied purpose. In general, situations, where MB has been attempted for a variety of posterior pole diseases, are as follows- Eyes with pathological myopia (PM) associated with posterior staphyloma (PS) Eyes with Optic Pit abnormalities Eyes requiring scleral remodeling posterior to the equator, where routine SB may not be effective In all practical situations, pathological myopia having posterior staphyloma associated macular changes is presently the most common indications for MB surgery. The other 2 situations have been very rarely attempted with MB surgery, with limited

    Dr. Pradeep Susvar · Dr. Kushal Delhiwala
  7. 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
  8. Articles 1 Apr 2021 20 min read

    Uveitic Macular Edema

    Introduction: Macular edema is defined as swelling of the layers of neurosensory retina within the macula. Cystoid macular edema (CME) is a subtype of macular edema characterized by extracellular accumulation of fluid within the outer plexiform layer of the retina in the form of intraretinal cyst. It is known as one of the complications, that develops consequent to a final common pathway in diverse diseases affecting the blood-retinal barrier. CME is a major cause of visual loss in uveitis. The overall reported prevalence of visual impairment associated with uveitic CME is 33–42 % and is influenced by the age, location, severity, and duration of retinal edema. [1,2] In young age, the retinal tissue shows resistance to development of CME, but advanced age is independently associated with early development of CME, regardless of the duration of uveitis. In contrast, the most frequent causes of visual loss in pediatric uveitis are retinal scars and glaucoma. [3] Panuveitis and intermediate

    Dr. Amit H Palkar · Dr. Parthopratim Dutta Majumder
  9. Articles 1 Apr 2021 20 min read

    Polypoidal Choroidal Vasculopathy

    Introduction Polypoidal Choroidal Vasculopathy (PCV), first described by Yannuzzi et al1 in 1982, is a distinct clinical entity characterized by persistent recurrent serous leakage and hemorrhage in the macula, and is seen in the elderly population. The disorder was poorly understood earlier and had been described by various authors as recurrent pigment epithelial detachment (PED) and posterior uveal bleeding syndrome.2.5 The primary abnormality, as described by Yannuzzi et al,1, 2, 6involves the choroidal circulation, and the characteristic lesion is an inner choroidal vascular network of vessels ending in an aneurysmal bulge visible clinically as a reddish-orange spheroidal polyp like structure. More recently with improvement in choroidal imaging using Enhanced Depth Imaging and Swept-Source optical coherence tomography (EDI-OCT and SS-OCT), PCV is regarded as a part of the Pachychoroid spectrum of diseases and a variant of Type I choroidal neovascularization.7, 8, 9 Epidemiology The

    Dr. Giridhar Anantharaman, MS, FVRS · Dr. Jay Sheth, DNB, FVRS
  10. 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

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