Articles

151–160 of 232 articles Page 16 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 16 min read

    Ultrasound B-Scan: A Ready Reckoner for the Postgraduates

    The importance of ultrasound imaging cannot be stressed upon more than the fact that whether you are an anterior segment surgeon, posterior segment surgeon or oculoplastic surgeon, the indications for this modality transcend across all genres of ophthalmology. Many a time, postgraduates find this topic daunting to interpret. This article aims to simplify Ultrasound B-scan in terms of mechanics, terminology, actual procedure, and interpretation without delving deep into the confusing jargon. Some common conditions and their typical presentations will also be touched upon. For ease of understanding, we will divide this article into the following sections: History Basic physics and instrumentation Terminology Indications Examination techniques: basic and special Features of commonly encountered posterior segment conditions History Though the concept of ultrasound waves was known to humans in the 18th century (Lazzaro Spallanzini’s observation on the use of ‘sound whistles’ by bats in dark

    Dr. Anmol Naik, MS, DNB, FMRF, FICO (UK), MRCS (Ed), MNAMS · Dr. Shveta Gadewar, MS, DNB, FAEH
  2. 1 Apr 2021 15 min read

    Thyroid Eye Disease : A Review for the Postgraduates

    Introduction: Thyroid eye disease (TED) or thyroid-associated orbitopathy (TAO) also called Basedow-Grave’s disease. It is an autoimmune inflammatory disorder characterized by enlargement of the orbital fat and extraocular muscles.1 It is a consequence of thyroid gland dysfunction, where antibodies are targeted against thyrotropin receptors (TSHR) known as thyroid-stimulating globulin(TSI).1 It is independent of the serum level of the circulating hormone levels. 2 TED is characterized by an active or inflammatory stage and an inactive or fibrotic stage. The active or the inflammatory stage is characterized by inflammation, adipogenesis, and accumulation of extracellular fluid, glycosaminoglycans which in turn causes enlargement of the extraocular muscles and expansion of the orbital fat. Once the inflammation settles, there is predominant scarring of the orbital tissues which marks the onset of the fibrotic stage. The natural course of the disease is quite variable. The majority of TED

    Dr. Amber Dubey · Dr. Vazhipokkil Anju Chandran · +1 other
  3. 1 Apr 2021 19 min read

    A (VAST)IN Saga

    Vascular endothelial growth factor (VEGF)-A is a key mediator of angiogenesis. The discovery of VEGF-A, like many other major discoveries in medicine, happened partly by observations and partly by chance. Napoleone Ferrara and his team were working on a population of non-hormone-secreting cells from the anterior pituitary of cows. (1) One day Ferrara mixed some isolates from cultures of follicular cells with endothelial cells. Ferrara was surprised to see the rapidly proliferating endothelial cells started rapidly. Ferrara understood that the pituitary cells were secreting an angiogenic protein. With this observation, Ferrara worked on the isolation and cloning of this angiogenic protein. In 1989, Napoleone Ferrara and Hazel at Genentech laboratory were the first to isolate and clone vascular endothelial growth factor (VEGF). Ferrara recalls, “I worked on the isolation of VEGF in my spare time during my first six months to a year at Genentech. Once we cloned VEGF in 1989, the company b

    Dr. Bikramjit Pal · Dr. Parthopratim Dutta Majumder
  4. 1 Apr 2021 13 min read

    Ocular Tuberculosis

    Ocular involvement in TB has been recognized for a long time and was first described in 17111. The spectrum of tuberculosis (TB)-related uveitis is wide. Its diagnosis still remains a challenge due to the lack of uniformity in the diagnostic criteria along with difficulties encountered in confirming the diagnosis by the laboratory methods available. It is a major concern in countries endemic for TB, and intraocular TB is being increasingly reported from various regions2-4. The true prevalence of intraocular TB is not known in India. While it has been reported to be 0.39% in South India, it is much higher (9.86%) in North India1,5. Varying rates of its prevalence have been reported from the world over (0.5% in the U.S.A., 6.31% in Italy, 6.9% in Japan, and 10.5% in Saudi Arabia). The largest series of patients with presumed intraocular TB and their outcome has been recently reported from our center6. Pathogenesis Uveitis due to latent TB has been reported since long. However, their exac

    Dr. Reema Bansal · Prof. Vishali Gupta · +1 other
  5. 1 Apr 2021 17 min read

    Corneal Trauma and its Management

    Introduction The cornea is prone to a variety of injuries by virtue of its location as the window of the eye. Apart from chemical injuries, physical trauma to the cornea can range from epithelial abrasions to loss of integrity of the stroma. Corneal injuries of this nature can occur in two distinct populations – in young children from play-related activities, and in young adults from due to their work environment. Although the general principles of management are not too different, special consideration in the pediatric population must be given to the timing of appropriate surgical interventions as the developing visual system in children is prone to amblyopic visual loss. Males are usually more prone to ocular injury than females; this is seen clearly in children, while the ratio of boys vs girls involved in accidents with ocular trauma is 4:1 [1]. The injuries can be caused by large blunt objects often resulting in ruptures of other parts of the ocular coats as well. On the other han

    Dr. Sanjeev P Srinivas · Dr. Amanda Mohanan · +1 other
  6. 1 Apr 2021 20 min read

    Ocular Syphilis

    Introduction: Syphilis is considered as a great mimicker due to its varied protean manifestations. It was first recognized in Europe in the late 15th century.[1] There have been several hypotheses regarding the origin and spread of syphilis and it is believed that the disease was brought back from the New World by the crew of Christopher Columbus, some of whom likely had syphilis on returning to Spain. Since the advent of Penicillin in the mid-20th century, the incidence of syphilis has reduced however it still represents a larger global problem [2] and an estimated 12 million new cases of syphilis are added every year worldwide and more than 90% are from developing countries.[3] The risk is particularly higher in men who have sex with men (MSM) and socially marginalized groups and those with HIV Co-infection.[4] The 2015 statistics from The Center for disease control and prevention (CDC) reported a 7.5 per 100,000 population of primary and secondary syphilis. (4). There has been a rec

    Dr. Mudit Tyagi · Dr. Subhakar Reddy
  7. 1 Apr 2021 9 min read

    A New Paradigm for Refractive Surgery: SMILE-Small Incision Lenticule Extraction

    Automated lamellar keratoplasty (ALK) was a technique to physically remove a refractive lenticule (the lenticule was merely a disc of corneal tissue) from the cornea after lifting a hinged flap and exposing the stroma. A mechanical microkeratome was used to do both steps of the ALK procedure. In the LASIK procedure, the refractive lenticule was ablated with the excimer laser, while the hinged flap was still created with the mechanical microkeratome. In a later iteration, Femto-LASIK involved creation of the hinged flap with a femtosecond laser, and an excimer laser was used to ablate the refractive lenticule. SMILE, a relatively new technique of performing refractive surgery, uses a femtosecond laser for all steps of the keratomileusis procedure. SMILE involves the creation of a refractive lenticule within the cornea using a femtosecond laser, and subsequent extraction of the refractive lenticule from within the cornea. The refractive error that needs to be treated defines the shape of

    Dr. Rupal Shah M.S
  8. 1 Apr 2021 17 min read

    Entropion And Ectropion

    Entropion is the turning inward of the eyelid margin. Unlike ectropion, it is symptomatic and injures the ocular surface. The patient seeks medical care early. Ectropion is an eyelid malposition in which the eyelid margin does not oppose the globe. We shall discuss the relevant anatomy and clinical examination for the two entities together. Relevant Anatomy The eyelid can be grossly divided into Anterior lamella composed of skin and orbicularis Posterior lamella composed of tarsus and conjunctiva Factors contributing to the stability of the lower eyelid Appropriate horizontal tension of the lower lid so that the eyelid is apposed to the eyeball. This is supplied by the medial and lateral canthal tendons. Lower lid retractors applying appropriate tension to the inferior margin of the tarsus, pulling the lower edge of the tarsus inferiorly, and thus preventing the lid margin from turning inward as in entropion, or outward as in ectropion. Synchronous movement of the inferior rectus and l

    Dr. Roshmi Gupta · Dr. Rwituja Thomas · +1 other
  9. 1 Apr 2021 23 min read

    Evaluation of The Optic Nerve Head in Glaucoma

    Introduction The diagnosis of primary open-angle glaucoma is based on the triad of increased intraocular pressure, visual field changes and optic nerve head changes. Apart from the glaucomatous changes in the optic nerve head, the other two factors in isolation lack diagnostic sensitivity. In fact, studies have shown that careful evaluation of the optic nerve head has high specificity and that an experienced observer may be better in distinguishing a normal from a glaucomatous disc as compared to any other technology, like the HRT or OCT.[1-3] IOP can be normal in 50% of patients of glaucoma.[4] Studies by Quigley et al have shown that up to 40% of the axons could be lost before a visual field defect develops on Goldmann perimetry and that 20% of axons are lost before a 5 db loss is detected on standard automated perimetry.[5] So to pick up early or pre-perimetric glaucoma, in the absence of imaging, a sound knowledge of assessment of optic nerve head changes in glaucoma is imperative.

    Dr. Sahebaan Sethi
  10. 1 Apr 2021 13 min read

    Binocular Indirect Ophthalmoscopy : The Beginner's Guide

    The technique of examining the fundus of the eye is called ophthalmoscopy. In direct ophthalmoscopy, a virtual and erect image of the fundus is seen. In indirect ophthalmoscopy, a real and inverted image is formed between the condensing lens and the observer. The advantage of stereopsis (depth perception) and a larger field of view makes indirect ophthalmoscope (IDO) more useful both in retina clinics and during posterior segment surgeries. Inventions and innovations The journey of developing ophthalmoscopy began with an idea by the great physicist, Hermann von Helmholtz, who described the optical principles of direct ophthalmoscopy in 1851 (Fig:1a). This was followed by series of innovations and methods of examination including the indirect method of ophthalmoscopy developed by Reute in 1852 (Fig:1b), binocular model by Marc-Antoine Giraud-Teulon (Fig:1c) and more practical hand-held reflex-free binocular ophthalmoscope by Allvar Gullstrand (Fig:1d). It was Charles Schepens who popula

    Dr. Nagesha CK