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#Review

86 articles
  1. Articles 1 Apr 2021 20 min read

    Acanthamoeba Keratitis: A review for the Postgraduates

    Eye diseases affecting the cornea are a major cause of blindness worldwide. Among different infectious agents, bacteria, fungi, viruses and protozoans may be causes of keratitis. This article is about the keratitis caused by protozoa. Three amoebic parasites are thought to be significant to human disease, entamoeba which is responsible for amoebic dysenter, naegleria which causes amoebic meningoencephalitis and acanthamoeba which is known for causing keratitis and granulomatous amoebic encephalitis. Acanthamoeba is a ubiquitous, free living protozoa of the subphyla Sarcodina. It is considered as opportunistic pathogen in humans. Acanthamoeba keratitis is a potentially devastating corneal infection which can lead to severe visual loss. Epidemiology: Acanthamoeba keratitis (AK), is rare in the general population (estimated incidence: 1.4 per million person- year) but much frequent in contact lens wearers. The incidence of the disease in developed countries is approximately 1-33 cases per

    Dr. Hema Joshi, MBBS, DO, DNB
  2. 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
  3. Articles 1 Apr 2021 39 min read

    Fungal Keratitis: A Review for the Post-Graduates

    Introduction Fungal or mycotic keratitis is a leading cause of ocular morbidity, opacification and preventable blindness.1 The approximate annual incidence of fungal keratitis in India is said to be 11.3/10,000 population.2 Frequently it is caused by filamentous fungi (Aspergillus, Fusarium, Curvularia) in the tropical areas, while in temperate regions it is predominantly caused by Candida species (C. albicans, C. Parapsilosis). It is considered as one of the most difficult forms of microbial keratitis for the Ophthalmologist to diagnose and manage. Medical therapy alone is often inadequate and surgical therapy like therapeutic penetrating keratoplasty, conjunctival flap, lamellar keratoplasty or cryotherapy is required for control of infection. Epidemiology and Demographics Fungal keratitis incidence or prevalence is more in tropical regions of the world like India and Southern USA and is less commonly encountered in the temperate zones.3 In East India, fungal keratitis was found to b

    Dr. Ankit Anil Harwani · Dr. Meena Lakshmipathy
  4. Articles 1 Apr 2021 9 min read

    Embryology of Eye

    Introduction The eyeball development begins early in the 4th week of intrauterine life with formation of optic vesicle (a diverticulum) from diencephalon. The structure of eyeball is shown in Figure 1. Various components of eyeball are derived from the following sources: Retina, iris and optic nerves are derived from optic vesicle that arises from neuroectoderm of diencephalon. Lens and corneal epithelium are derived from lens placode that arises from surface ectoderm. Fibrous and vascular coats of eyeball are derived from mesodermal condensation surrounding the optic vesicle. Choroid and sclera are derived from migrating neural crest cells. Figure 1: Fully developed eyeball Optic Vesicle and Lens Vesicle Formation of optic sulcus: On 22nd day, wall of the diencephalon shows thickening and depression to form optic sulcus. Formation of the optic sulcus or groove is the first indication for development of the eye (Figure 2A). Formation of optic vesicle: Optic sulcus further invaginates l

    Dr. Yogesh Sontakke
  5. Articles 1 Apr 2021 7 min read

    Panophthalmitis: A Ready Reckoner for Postgraduates

    Introduction Panophthalmitis is a severe ocular and orbital condition which can lead to phthisis bulbi or may necessitate evisceration. Severe inflammation of the anterior and posterior segments is frequently accompanied by microbial keratitis, necrotizing scleritis, and perforation or rupture following trauma. The disease develops rapidly and the prognosis is poor. The management of patients with intractable panophthalmitis remains challenging with eye salvage almost impossible in most cases. Etiology and Pathogenesis Panophthalmitis is a purulent inflammation of all coats of the eyeball including intraocular structures. Although post-traumatic endophthalmitis is the most common preceding event, the infection can result after postoperative endophthalmitis following cataract surgery, keratoplasty, or rarely after posterior segment procedures. It can also be caused by septicemia or can spread from a pus-producing infection in another part of the body. [Table 1] Organisms implicated incl

    Dr. Namrata Adulkar
  6. Articles 1 Apr 2021 18 min read

    Angioid Streaks

    Angioid streaks are visible irregular crack-like dehiscences in Bruch’s membrane that are associated with atrophic degeneration of the overlying retinal pigmented epithelium. Despite 50 % of cases being idiopathic, this condition grabs attention as it requires good history taking and workup to determine the cause. Historical background The first description of angioid streaks was provided in 1889 by Dr. Robert W. Doyne, an English ophthalmologist. He noticed irregular, jagged deeply pigmented lines especially around the discs of both eyes in a patient who sustained trauma in both eyes and attributed it to be due to the rupture of pigment layer of retina. [1] Because of their resemblance to blood vessels, Herman J. Knapp, a German-born American ophthalmologist coined and introduced the term "angioid streaks" in 1892. [2] They are also known as Knapp’s striae. Clinical examination with histopathological findings by Bock in 1938 in two patients with pseudoxanthoma elasticum confirmed that

    Dr. Remya Paulose · Dr. Bhavik Panchal · +1 other
  7. Articles 1 Apr 2021 15 min read

    Paediatric Retinal Vascular Diseases

    Introduction This chapter will discuss pediatric retinal vascular diseases like Persistent Fetal Vasculature, Familial Exudative Vitreo Retinopathy and Incontinentia Pigmenti Persistent Fetal Vasculature (Persistent Hyperplastic Primary Vitreous) Definition Persistent hyperplastic primary vitreous (PHPV) is a congenital ocular disorder in which fetal vasculature does not regress after birth. It is unilateral approximately 90% of the time. No single gene has been identified. It can vary from very subtle with no visual disturbance to as severe as phthisis bulbi or secondary glaucoma. The prognosis can be good if early intervention is planned. Due to its wide spectrum of presentation, it has now been renamed as persistent fetal vasculature (PFV).1 Pathogenesis The fetal vasculature is composed of two parts: Tunica vasculosa lentis. It is situated anteriorly encircling the lens. It has anterior and posterior divisions. Anteri­or division has additional attachments to the pupillary frill of

    Parag K. Shah, DNB · Dr. V. R. Saravanan · +1 other
  8. Articles 1 Apr 2021 20 min read

    Fungal Endophthalmitis and it's Management

    Endophthalmitis is a potentially devastating ocular disease that may lead to permanent loss of vision. It is caused by bacteria in the majority of the cases. However, fungal endophthalmitis though rare has a poor prognosis and usually diagnosed late. The incidence of fungal endophthalmitis has increased in recent years, particularly in developing countries. 1-3 Unlike bacterial infections, we do not have much choice of medications in fungal infections. The fungus is slow-growing and we have limited choice of antifungals which act slowly. These are usually diagnosed late as patients are less symptomatic but have more signs. Moreover, fungal culture takes longer time and identification requires more expertise. Polymerase chain reaction (PCR) techniques can even detect dead remnants. Patients are usually treated as bacterial infections and would have received steroids before they are diagnosed to have fungal endophthalmitis. The prognosis of fungal endophthalmitis depends on the magnitude

    Dr. Sugandha Goel · Dr. Ekta Rishi
  9. Articles 1 Apr 2021 13 min read

    Choroidal Melanoma: Ready Reckoner for the Postgraduates

    Introduction Uveal melanoma is the most common primary intraocular malignant tumor in adults [1]. Second most common type of primary malignant melanoma after cutaneous melanoma. It arises from neuroectodermal melanocytes within the uveal tissue. Epidemiology There is strong racial variation in the incidence, with the white population most commonly affected. The mean age-adjusted incidence of uveal melanoma in the United States is 5.2 per million per year [2]. Males had a significantly higher age-adjusted incidence of 6.0 per million population compared to females, where the average age-adjusted incidence was 4.5 [3]. Malignant melanoma of the choroid is rare in dark pigmented races and has been reported infrequently in the Asian Indian population.[4] Ultraviolet (UV) radiation has been suggested as a major cause of malignant melanoma of the skin and uvea[5] because of the increased incidence and mortality among Caucasians living in tropical regions, where solar radiation is more intens

    Dr. Isha Agarwal · Dr. Vikas Khetan
  10. Articles 1 Apr 2021 17 min read

    Fundus Fluorescein Angiography and Indocyanine Green Angiography: Made Easy for the Postgraduates

    Introduction and Gross Anatomy: The retinal and choroidal circulatory system can be visualized in vivo in the presence of normal media clarity. Many important diseases of the retina are related to or associated with the changes in the vasculature of the retina and/or choroid. Hence, it is important to understand the circulatory systems involved to better recognize disease states of the posterior segment. The retinal and choroidal vascular anatomy can be basically divided into 3 parts: Retinal and choroidal vasculature Superficial and deep capillary plexus Inner and outer blood-retinal barriers A: Retinal and Choroidal Vasculature: The retina receives its nutrition from two discrete circulatory systems—the retinal and the choroidal blood vessels. Both are derived from the ophthalmic artery, which is the first branch of the internal carotid artery. The major branches of the ophthalmic artery are the posterior ciliary arteries, the central retinal artery, and the muscular branches. [1] Th

    Dr. Ramesh Venkatesh · Dr. Sajjan Sangai · +1 other

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