Articles

191–200 of 232 articles Page 20 of 24
All Cornea 36 Cataract 17 Glaucoma 13 Retina & Vitreous 72 Neurophthalmology 8 Oculoplasty 15 Uvea & Inflammatory Diseases 24 Miscellaneous 20 Oncology 9 Pediatric Ophthalmology 15
  1. 1 Apr 2021 9 min read

    Intermittent Exotropia Simplified for the Postgraduates

    Intermittent exotropia (IXT) is the most common type of strabismus in children as well as adults, especially in the Asian and South Asian populations. Owing to the intermittent nature of exotropia there is usually good binocular function and stereoacuity at near fixation Small-angle exotropia is observed in normal neonates which usually disappears by the age of 2-4 months. Most adults will have small exophoria usually less than 10 when fully dissociated. Epidemiology Like all forms of strabismus, exotropic deviations can be manifest or latent, and if the former, intermittent or constant. Intermittent exotropia is by far the most common form of manifest XT. Exodeviations occur about one-third less frequently than esodeviations in North America and Europe and occur more frequently in the Asian population. Intermittent exotropia is more common in females with a ratio of 2:1 (F: M). Intermittent exotropia usually noticed by parents in early childhood (2-5 years). Clinical features Intermit

    Dr. Amr Mohamed · Dr. Sowmya R, MS,FMRF, FAICO
  2. 1 Apr 2021 47 min read

    Instruments used in Corneal Procedures and Surgeries

    Although tales and myths of ocular surgery and organ transplantation appear in numerous ancient texts, the earliest accounts of ophthalmic diseases were written as a treatise by Sushruta, in the 6th century BC. Sushruta described 76 eye diseases, out of which 51 required surgical treatment. In the western world, the concepts of corneal surgery date back to Greek physician Galen (130-200AD). The concepts to improve corneal clarity by surgery were developed over the next centuries and especially in the 17th and 18th centuries. But the major scientific progress and experimentation in the field of corneal surgeries happened in the 19th century. The progress in corneal surgery was hindered by a lack of understanding of immunology, asepsis, surgical procedures, and of course, the lack of proper instrumentation. Emmert Wolf wrote over a century ago, “A man is only as good as his tools.” Early surgeons were hampered by a lack of proper surgical instruments. Over the centuries, innumerable opht

    Dr. Hema Joshi, MBBS, DO, DNB · Dr. Ankita Patil
  3. 1 Apr 2021 29 min read

    Ocular Surface Squamous Neoplasia

    A. Introduction There have been multiple refinements in the terminology of the epithelial squamous neoplasia until the introduction of the term “Ocular surface squamous neoplasia” (OSSN) by Lee and Hirst in 19951. OSSN is an umbrella term and refers to a spectrum ranging from mild/moderate/severe dysplasia to carcinoma in situ to invasive squamous cell carcinoma involving the conjunctiva and/or cornea2-4. OSSN is the most common tumor of the ocular surface. According to the epidemiological studies, the worldwide incidence of OSSN is 0.02 to 3.5 cases per 100,000 people. Incidence increases with decreasing latitude, being higher in countries located close to the equator. OSSN predominantly occurs in the elderly age group (6th to 7th decade) and in male gender 5-9. B. Etiology and pathogenesis10-27 The presumptive risk factors implicated in the etiology of OSSN include: Excessive exposure to ultraviolet radiation Heavy cigarette smoking Immunosuppressive conditions: Human Immunodeficienc

    Dr. Kavya M Bejjanki · Dr. Swathi Kaliki
  4. 1 Apr 2021 3 min read

    Five things you should know about Micropulse LASER in Glaucoma Management

    Glaucoma is a leading cause of irreversible blindness worldwide, with more than 70 million people affected. Traditionally treatment options include topical medications, laser trabeculoplasty, incisional surgeries, glaucoma drainage implants (GDD), and cycloablative procedures. GDD and ciliary body destruction is generally reserved for refractory or end-stage glaucoma in eyes with poor visual potential. Transscleral cyclophotocoagulation (TSCPC) Transscleral cyclophotocoagulation (TSCPC) is a cyclodestructive procedure designed to target the melanin in the pigmented ciliary body epithelium, thereby decreasing the rate of aqueous humor production. Numerous studies have confirmed the IOP-lowering ability of TSCPC and also reported the risk of developing serious complications with this procedure, such as persistent ocular inflammation, vision loss, hypotony, phthisis bulbi, and rarely sympathetic ophthalmia. Therefore, TSCPC, which conventionally uses the continuous-wave diode laser, has b

    Dr. Murali Ariga
  5. 1 Apr 2021 23 min read

    Ocular Sarcoidosis: A Review for the Postgraduates

    Introduction: Sarcoidosis is a chronic multisystemic granulomatous disorder caused by an exaggerated cellular immune response to a variety of self or non-self-antigens in a genetically predisposed individual resulting in non-caseating granulomas. Ocular involvement occurs in 25-60% of systemic sarcoidosis at some point of time1. In this article, we look at the emerging literature on epidemiology, pathogenesis, clinical profile, and management in ocular sarcoidosis. Epidemiology: Sarcoidosis has an overall incidence of 6-10 per 100,000. Although sarcoidosis occurs worldwide, it is predominant in certain ethnic and racial groups like the Afro-Caribbean, Scandinavian, and Irish populations2-4. Highest incidence of ocular sarcoidosis is in the 20-40-year age group. Some studies show two peaks of incidence for ocular sarcoidosis the first at ages 20-30 and the second at ages 50-605. There is also a higher incidence of ocular involvement in women4. The reported incidence of ocular sarcoidosi

    Dr. Vinaya Kumar Konana · Dr. Kalpana Babu
  6. 1 Apr 2021 10 min read

    Slit-lamp Biomicroscopy

    A slit-lamp is a binocular microscope used for eye examination using a slit-like light beam. In 1911, Allvar Gullstrand a Swedish Ophthalmologist designed table-mounted binocular eyepiece for 3-dimensional visualization of optically clear eye structures. Later Otto Henker, combined Gullstrand slit lamp with Czapski’s binocular microscope resulting in first slit lamp biomicroscope, allowing hand-free examination of an eye.1 The optical design of the Slit-Lamp Biomicroscope (SLB). Due to the miniature size of the anterior segment of the eye, we need high magnification and clarity to appreciate finer details. This can be achieved by having 2 convex lenses at the observer end (eyepiece) separated at its focal distance (astronomical telescope type alignment) and, a concave-convex combination (Galilean telescope type alignment) at the examinee’s end for further magnification of the image. Telescopic arrangements of lenses need to be focused at near, hence a plus power objective lens is fixed

    Dr. Nagesha C K · Dr. Shruthi M N
  7. 1 Apr 2021 5 min read

    Ten Pearls for Performing Vitrectomy in Diabetic Retinopathy

    Important terms: Truncation: To relieve all the surrounding traction 360 degree Segmentation: Dividing a larger membranes/FVP into smaller islands of FVP by 360-degree truncation around them. Delamination: Separation of these membranes/FVP from the retinal surface to which they are firmly adherent by creating a plane of dissection between them. Pearl #1 When not to perform vitrectomy in diabetic retinopathy? Answer: In cases of extramacular tractional retinal detachment (TRD) when the fovea is attached and the patient has a comparative good vision the extramacular TRD can be observed. Charles and Flinn reported only 21% of extramacular TRD extending into macula without any surgical intervention. Also, DRVS (Diabetic retinopathy vitrectomy study) reports that only 23% of eyes with TRD developed severe visual loss at 2 years. Also, early intervention in such extramacular TRD’s can sometimes lead to more harm than benefit owing to the surgery itself. Pearl #2 First step should always be c

    Dr. Raja Narayan
  8. 1 Apr 2021 49 min read

    Visual Electrophysiology Made Simple for the Postgraduates

    Visual electrophysiology is an extremely useful tool to study the retinal function objectively. It assesses the functional aspects of not only the retina but also the visual pathway as a whole. Even in this era of advanced imaging, one cannot ignore the importance of the functional aspects of the cellular network in the retina. The commonly used tests with their salient applications are enumerated in Table 1. S.no Test Application 1. Electroretinogram(ERG) Elicits mass response from the Retina 2. Electro-oculogram(EOG) Assesses the function of the Retinal pigment epithelium 3. Pattern ERG(PERG) Differentiates macular and optic nerve pathology 4. Multifocal ERG(MfERG) Picks up focal retinal pathology and maps out the topography 5. Photopic Negative Response(PhNR) Tests the function of retinal ganglion cells 6. Visual Evoked Potentials(VEP) Assesses the visual pathway up to the occipital cortex 7. Multifocal VEP(MfVEP) Picks up focal dysfunction of the visual pathway and maps the topogra

    Dr. Parveen Sen · Karthika Pandurangan · +1 other
  9. 1 Apr 2021 14 min read

    A Beginner's Guide to Ultrasound Biomicroscopy

    Introduction: Anterior segment ocular imaging has gone through various inventions starting from the ultrasound in the 20th century to the recent AS- OCT.1 Ultrasound bio-microscopy, one of the ocular imaging devices is a high-resolution technique, which allows in vivo assessment of the structures of the anterior segment of the eye where cross-sectional images of ocular structures are obtained at microscopic resolution. 2The higher frequency of UBM ranging between 35 and 50 MHz, gives a depth of about 4 mm and an axial and lateral resolution of approximately 25 and 50 microns, respectively. 3 Being a non-invasive technique, efficient regardless of the clarity of the optical media and due to its portability can be performed both in adults and children with no complications.4 The internal acoustic characteristics of UBM, accompanied by the very fine backscatter speckle patterns, permit clear differentiation of ocular tissue at various levels.5 UBM imaging has been very useful in understan

    Dr. Sowkath Ali · Dr. Eunice Goh · +1 other
  10. 1 Apr 2021 35 min read

    Clinical Applications of Multicolor Imaging

    Multicolor imaging (MCI) is a non-invasive retinal imaging modality available in the Spectralis platform (Heidelberg Engineering, Heidelberg, Germany). It simultaneously acquires three reflectance images of the retina using three individual lasers of different wavelengths: blue (488 nm), green (515 nm), and infrared (820 nm). These penetrate the tissue to different depths, simultaneously capturing and depicting information originating from different retinal structures. The infrared reflectance (IR) image visualizes structures at the level of the outer retina and choroid. The green reflectance (GR) image allows imaging of retinal blood vessels, hemorrhages, and exudates. The blue reflectance (BR) particularly provides details of the inner retina and the vitreoretinal interface such as epiretinal membranes, retinal nerve fiber layer (RNFL) thinning, and macular pigment changes. The information from these three images is integrated to form a composite multicolor image.1 Color fundus photo

    Dr. Sugandha Goel · Dr. Rupak Roy