## Metazoa
<ul>
 <li>Multicellular organisms with organ systems</li>
 <li>Aka helminths</li>
 <li>Divided into nematodes and platyhelminths</li>
</ul>

## Toxocariasis
<ul>
 <li>Toxocara canis is a ubiquitous canine parasite transmitted by dogs and cats</li>
 <li>Helminth&nbsp;</li>
 <li>Eggs are secreted in the faeces</li>
 <li>
 Larvae migrate through the GI tract and disseminate via the bloodstream (eg to the eye).
 Systemic disease is rarely fatal.
 </li>
 <ul>
 <li>
 The larvae themselves are not inflammatory but when they die, the inflammatory response is
 triggered
 </li>
 </ul>
 <li>Infection triggers an IgE-mediated immune response with eosinophilia</li>
 <li>Appears as a large inferior white intraocular vitreoretinal mass (leucocoria)</li>
 <li>
 Can manifest as a low-grade fibrous reaction or can be rapid retinal inflammation with vitritis
 and pars planitis
 </li>
 <li>Tractional retinal detachment may occur</li>
 <li>Associated with &lsquo;dragging&rsquo; of the optic disc</li>
 <ul>
 <li>But no intraocular calcification as seen in retinoblastoma&nbsp;</li>
 </ul>
 <li>
 Puppies and lactating bitches are the main source of infective ova (in adult dogs, most larvae
 become encysted in a dormant state and do not mature therefore are not transmitted)
 </li>
 <li>Treatment: tiabendazole or albendazole. Steroids to reduce inflammation</li>
</ul>

## Onchocerciasis
<ul>
 <li>Onchocerca volvulus of the filariasis subdivision of nematodes</li>
 <li>River blindness</li>
 <li>Simulium blackfly acts as a vector and breeds in fast flowing rivers</li>
 <li>Blackfly bite transfers infective larvae to the human host</li>
 <li>Adult worms are only found in humans</li>
 <li>They sequester in collagenous nodules and can survive in the skin for 30 months</li>
 <li>Ocular infection occurs via subcutaneous migration of worms</li>
 <li>
 Anterior and posterior segment inflammation with sclerosing keratitis,{' '}
 chorioretinitis and optic neuritis, depigmentation, pruritis and &ldquo;hanging
 groin&rdquo;
 </li>
 <ul>
 <li>Secondary glaucoma and cataract</li>
 </ul>
 <li>
 Stimulates a low-grade immunosuppressive response which facilitates the longevity of the adult
 and larval worms to perpetuate the life cycle
 </li>
 <li>
 The filariae also harbour Rickettsia-like bacteria known as Wolbachia and are thought to mediate
 the immunopathology associated with ocular onchocerciasis
 </li>
 <ul>
 <li>Susceptible to doxycycline</li>
 </ul>
 <li>Mazzotti skin test detects infection</li>
 <li>
 Ivermectin can be used for treatment
 </li>
</ul>

## Loa loa
<ul>
 <li>Chrysops flies are vectors</li>
 <li>Can live for 17 years in humans and migrate through subcutaneous tissues</li>
 <li>High eosinophilia is strongly suggestive</li>
 <li>Calabar swellings are pathognomonic</li>
 <li>Worms may be seen traversing the conjunctiva</li>
 <li>Diagnosed by finding microfilariae in the blood</li>
</ul>

Metazoa Multicellular organisms with organ systems Aka helminths Divided into nematodes and platyhelminths Toxocariasis Toxocara canis is a ubiquitous…

Microbiology

Nematodes

Intro

FRCOphth Part 1 Study Notes

Orbit and ocular adnexae

Orbit

Extraocular Muscles

Orbital Blood Vessels

Paranasal Sinuses

Lacrimal Glands

Tear Film

Eyelids

Blinking

Anterior segment - ocular surface

Conjunctiva

Conjunctivitis

Sclera

Cornea

Corneal Structure And Development

Corneal Physiology

AC to Lens

Angle

Ciliary Body

Aqueous Humour Dynamics

Iris

Pupil

Lens

Posterior segment

Choroid

Vitreous

Retinal Macrostructure

Neurosensory Retina

Retinal Pigment Epithelium

Neuroanatomy

Venous Sinuses

Cerebral Ventricles

Cerebral Blood Supply

Supranuclear Gaze Pathways

Head And Neck Autonomic Nervous Supply

Head And Neck Glands

Osteology

Nerves

Muscles And Pharyngeal Arches

Extraocular Nerves

Sensory Nerves

Physiology

Physics Of Blood Flow

Neuronal Control Of Blood Vessels

Oxygen-Haemoglobin Dissociation Curve

Cytochrome p450

Pituitary Gland

Thyroid Hormone Production

Insulin

Glucagon

Parathyroid Hormone

Corticosteroids

Catecholamines

Cardiac Cycle

Renal Physiology

Fluid Balance

Acid-Base Balance

Muscle Physiology

Sensory Fibres

Cutaneous Receptors

Endocytosis

Glycosaminoglycans

Condensed Ocular Biochemistry

Eye Movements

Accomodation

Vision

Visual Cycle And Phototransuction

Visual Pathway

Visual Acuity

Colour Vision

Binocular Vision

Pathology

Collagen

Tissue Damage

Inflammation

Disease Entities

Wound Healing

Thrombosis / Atherosclerosis

Cell Growth

Neoplasia

Histopathology

Nystagmus

Free Radicals And Antioxidants

Immunology

Ocular Immunology

Viral Infections

Bacterial Infections

Fungal Infections

Protozoa

Antimicrobials

Genetics

Chromosomes

Mitosis

Meiosis

Genes

Polypeptide Synthesis

Histones

MicroRNA

Hardy-Weinberg Equilibrium

Mutations

Chromosome Defects

Autosomal Inheritance

X-Linked Inheritance

Mitochondrial Inheritance

Multifactorial Inheritance