Topic

#Cornea and External Eye Diseases

34 articles
  1. Articles 2 Apr 2021 16 min read

    Peripheral Ulcerative Keratitis

    Peripheral ulcerative keratitis (PUK) is a form of ocular inflammation that involves the peripheral portion of cornea and may be associated with systemic conditions such as Rheumatoid Arthritis(RA), Wegener’s Granulomatosis(WG), and other systemic conditions. It is a potentially devastating disorder consisting of a crescent-shaped destructive inflammation at the margin of corneal stroma that is associated with an epithelial defect, presence of stromal inflammatory cells, and progressive stromal degradation and thinning. The onset of Peripheral Ulcerative Keratitis has been linked to various anatomical factors of central and peripheral cornea and adjoining limbus. Though the local concentration of small and medium weight proteins like IgA, IgG and most complements are similar in central and peripheral cornea, the peripheral cornea has been found to be associated with higher concentrations of higher molecular weight(HMW) protein molecules like IgM and complement C1(5 times), possibily ow

    Dr. A. Agarwal, MD · Dr. A.Panda, MD, FAMS, FICS, FICO, MRC Ophthalmology
  2. Interesting Reads 2 Apr 2021 7 min read

    Vernal Keratoconjunctivitis - FIVE Important Points We Should Know

    Allergic conjunctivitis, which includes a spectrum of clinical entities is one of the most common conditions with which patients present to a general ophthalmologist. They include milder forms like seasonal and perennial allergic conjunctivitis as well as severe forms like vernal and atopic which can be sight-threatening. In spite of common clinical and immunological features vernal keratoconjunctivitis differs from the rest in myriad ways. (1)This article brings forth five most pertinent points which will not only improve the understanding but also help identify and manage it. 1. Vernal keratoconjunctivitis can have three distinct forms Vernal keratoconjunctivitis (VKC) is a bilateral, chronic, usually seasonal, recurrent allergic inflammation of the conjunctiva. It mainly affects boys living in tropical countries in their first or second decade of life, mostly seasonal but in tropical countries, it can be perennial too. In the temperate regions, in many parts of Africa, Latin America

    Dr. Shweta Agarwal · Dr. Bhaskar Srinivasan · +1 other
  3. Articles 2 Apr 2021 20 min read

    Corneal Topography

    WHAT IS CORNEAL TOPOGRAPHY? Corneal topography is the study of the shape of the corneal surface. Traditionally, such measurements were limited to the near-spherical central portion of the anterior corneal surface. With the advent of corneal refractive procedures, the necessity to study the more peripheral parts of the cornea and to understand better the optics of both the anterior and posterior corneal surfaces has spawned a number of new devices that allow the clinician to better understand corneal shape, power, and optical performance. EVOLUTION OF CORNEAL TOPOGRAPHY KERATOSCOPY: It is the evaluation of the corneal surface using circular mires reflected from its surface. The earliest device designed to perform this function was the PLACIDO’S DISC, developed by Antonio Placido. It consists of equally spaced alternating black and white rings with a hole in the centre to observe the patient’s cornea. The central opening houses a convex lens for magnification and to aid the examiner’s ac

    Dr. Srinivas K Rao, DO DNB FRCSEd · Dr. Ramya Subramaniam, DNB
  4. Students Gallery 2 Apr 2021 6 min read

    Documentation & Drawing in Ophthalmology

    Anterior segment finding Documentations From the days of Hippocrates documentation has been a cornerstone of clinical science. But somewhere down the line this has become a lost art rarely ever practiced by many of us. We tend to ignore or to say correctly run away from it under many pretexts like its time consuming, it’s of no use, etc. And surprisingly this resistance to document is prevalent not only among juniors but spans across the whole spectrum of practitioners. So at times we really ponder is documentation really necessary? The answer is an emphatic yes – the reasons being It’s a standard clinical practice worldwide Follow up is possible only if you can compare it with your previous records. Will help you medico legally Last but not the least unless you are documenting it you have not probably seen it correctly(you think you have seen it all but the moment you come to draw it you find that you don’t remember where the break was it at 1 o’clock or 3 o’clock position and so on).

    Dr. Parthopratim Dutta Majumder
  5. Articles 2 Apr 2021 10 min read

    Chemical Injuries of Eye - An Update.

    Introduction It is very frequent to encounter chemical injury in our routine ophthalmic practice. Most of the chemical injuries are minor, which heal without any squeal. Most are acids and alkalis. Alkali injuries are more common (nearly twice) than acids and are more severe in nature. It is of utmost importance to recognize the nature of chemicals for treating such patients. Here, we review the chemical injuries of the eye with their recent management update. Epidemiology Chemical burn 7.9-9% of all reported ocular burns. 23 -42% are bilateral. Young males are affected mostly. Most are industrial accidents (at workplace 60-70%, at homes 25-30%, criminal assault, and others comprise 2-3%) Sources of common chemicals Alkalis Acids 1.Ammonium hydroxide and Ammonia- fertilizers, laboratory refrigerator, household cleansing agent, bleaching powder 2. Sodium hydroxide-drain cleaner, soap 3. Potassium hydroxide- soap 3.Calcium hydroxide- plaster, cement, mortar, whitewash(chuna) 4.Magnesium

    Dr. Sushobhan Dasgupta · Dr. Tarannum Shakeel · +1 other
  6. Articles 1 Apr 2021 10 min read

    Cornea Edema : Ready Reckoner for the Post Graduates

    Corneal edema is defined as the increase in the thickness of cornea due to the accumulation of extracellular fluid in epithelium and stroma resulting in loss of corneal transparency. Pathophysiology: Cornea remains in a relatively dehydrated state maintaining a 78% hydration level. Corneal hydration depends on 5 factors. 1. Stromal swelling pressure (SP) This is the tendency of stroma to swell due to interfibrillary proteoglycans and other proteins. The normal stromal pressure is 55mmHg. Imbibition pressure (IP) – It is a negative pressure exerted by glycosaminoglycans by which fluid is drawn into the cornea. Intraocular pressure (IOP) = SP + IP 2. Barrier function The epithelium (Zonula occludens tight junction) offers twice the resistance to water flow compared to the endothelium (macula occludens tight junction) and the electrolyte resistance is 200 times higher in the epithelium than endothelium.1 3. Endothelial pump The endothelium pump function ensures, through active transport,

    Dr. Sumana Chatterjee
  7. 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
  8. 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
  9. Articles 1 Apr 2021 10 min read

    Ten Pearls for Descemet's Membrane Detachment Repair

    1. Embryology Understanding the embryological development of the cornea helps us appreciate the reasons for a Descemet's membrane (DM) detachment during surgery. After the lens vesicle separates from the surface epithelium, a wave of mesenchyme forms the primary corneal stroma. A second wave then forms the endothelium, which secretes the DM. The DM, hence, has a potential plane of separation from the corneal stroma, which we use to our benefit in DMEK surgery and which works against us in an inadvertent DM detachment. Throughout the life of an individual, the DM thickens as the posterior non-banded layer is secreted by the endothelium. The anterior fetal banded layer tends to remain the same. However, in most instances, the separation happens between the DM and the cornea stroma1. The thickness of the DM varies between 10 and 15 microns, increasing with age. DM does not regenerate after any damage2. 2. Cataract Surgery and DM Detachment A post-cataract DM detachment occurs in 0.26% of

    Dr. Amanda Mohanan · Dr. Sanjeev P Srinivas · +1 other
  10. Articles 1 Apr 2021 16 min read

    Herpetic Eye Disease Study: All You Should Know

    Herpes simplex virus (HSV) keratitis is the leading cause of corneal blindness in developed as well as developing countries. The ocular disease affects approximately 10 million people worldwide. Herpes viruses are a group of double-stranded DNA viruses with three subfamilies: alpha-, beta- and gamma- herpes viruses. HSV-1, HSV-2, and varicella-zoster virus (VZV) belong to the alpha-subfamily. HSV spreads by direct contact with virus shed by saliva or genital secretions. During primary infection, HSV-1 infiltrates the corneal epithelial cells. Here it lyses the host cells and releases virions which in turn infect neighboring cells. Then the HSV travels via neuronal cells to trigeminal ganglion and establishes a latent infection. HSV can remain latent for lifetime by storing its genome in the nucleus of the host neuronal cell. While latent, it produces latency-associated transcripts (LATs) that maintain the integrity of the viral genome. The latent HSV-1 can reactivate and return to the

    Dr. Hema Joshi, MBBS, DO, DNB

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