Chapter 1 - Basic science, investigations and lasers Flashcards
Which ocular strucuture are derived from the surface ectoderm
Conjuctival and corneal epithelium Nasolacrimal Duct Lens Lacrimal gland Eyelids
Which ocular structures are derived from the neuroectoderm
neurosensory retina
Pigment epithelium of retina, iris and ciliary body
pupillary sphincter and dilator muscles
optic nerve
Which ocular structures are derived from the neural crest
corneal endothelium trabecular meshwork strom of cornea, iris and cilirary body ciliary muscle choroid sclera orbital cartilage
Which ocular structures are derived from the mesoderm
extraocular muscles
blood vessels
schlemm’s canal endothelium
sclera (temporal portion)
Autosomal Dominant diseases
Congenital cataracts Best disease Fuchs’ corneal dystrophy (also sporadic) Granular and lattice corneal dystrophies Marfan syndrome Neurofibromatosis Retinitis pigmentosa (also AR or XLR) Retinoblastoma (most commonly sporadic) Stickler syndrome Tuberous sclerosis Von Hippel-Lindau (VHL)
AR-conditions
Congenital glaucoma (most commonly sporadic)
Oculocutaneous albinism
Stargardt disease
Retinitis pigmentosa-like conditions
X-linked recessive
Fabry disease
Lowe syndrome
Ocular albinism
Retinoschisis
X-linked dominant
Alport syndrome (also AR)
Mitochondrial inheritance
Kearns-Sayre syndrome
Leber hereditary optic neuropathy
describe myco bacteria
Acid-fast bacilli that are aerobic and non-spore forming. They contain a cell wall that does not allow Gram staining; Ziehl-Neelson stain is used.
Describe chlamydia
Obligate intracellular bacterium. They can exist in the form of either elementary bodies (infectious) or reticular bodies (found in host cells only) during their life cycle.
Yeast fungus -explain
Yeasts are unicellular microorganisms. A good example is Candida albicans. Candida is a commensal that reproduces by budding. It causes infection in immunocompromised patients and is the most common cause of endogenous endophthalmitis presenting with white fluffy retinal lesions.
Filamentous
Their cells grow in a branching-like pattern. Aspergillus spp. and Fusarium spp. are types of filamentous fungi. They are common in warm climates and can cause fungal keratitis, usually following ocular trauma
Dimorphic
These fungi have properties of both yeasts and filamentous fungi. Histoplasma capsulatum is a soil fungus, endemic in Mississippi and Ohio River Valleys. Transmission is via inhalation. It can cause presumed ocular histoplasmosis syndrome (POHS).
Toxoplasma gondii
Obligate intracellular parasite (protozoa). Cats are the definitive host. Transmission to humans is via fecal-oral spread, inhalation or undercooked meats. It can also be transmitted in pregnancy via vertical transmission. T. gondii can cause congenital or adult toxoplasmosis.
Acanthamoeba:
Protozoa that can be found in soil, water or swimming pools. It can cause severe keratitis.
Toxocara:
A helminth nematode (roundworm). Their hosts are cats and dogs. It can be transmitted to humans through fecal-contaminated material. It causes toxocariasis which presents with endophthalmitis in children
Onchocerca volvulus
The most common helminth-related ocular infection. The vectors are Simulium blackflies. It causes onchocerciasis (‘river blindness’) and is endemic in Africa.
Anti-biotics that inhibit cell wall synthesis
Penicillin
Cephalosporin
Vancomycin
Anti-fungals that inhibit cell membrane function
Imidazoles, amphotericin and nystatin
Anti-biotic that inhibits protein synthesis
Aminoglycosides
Tetracyclines
Erythromycin
Chloramphenicol
Anti-biotic that inhibits nucleic acid synthesis
Fluoroquinolones (DNA gyrase)
Metronidazole
Innated imune system cells
Neutrophils, macrophages, dendritic cells and the complement system
Adaptive immune system
immune response towards a specific antigen, mediated by lymphocytes (T and B cells).
