Qbank must know Flashcards
Synaptic terminals of the cones
Pedicles
Synaptic terminals of the rods
spherules
How many ganglion cells, cones and rods are there in humans:
There are 1 million ganglion cells, 6 million cones and 120 million rods in the human retina.
How does The ophthalmic artery enters the orbit?
Infero-lateral
The ophthalmic artery enters the orbit infero-lateral to the optic nerve
Lamina vitrea
Bruch’s membrane
Lamina fusca
Sclera proper and then episcleral tissue.
Lamina cribrosa
Transmits the optic nerve
Lamina densa
Basement membrane of the corneal epithelium.
Ciliary body width, pars plicata, pars plana
5-6 mm wide
pars plicata. It is 2mm wide
pars plana. It is approximately 4mm wide
Pars plicata how many ciliary processes
70 ciliary processes
Eccrine glands
i.e., sweat glands
Apocrine glands
associated with hair follicles, i.e. Moll’s glands
Holocrine glands
meibomian glands, sebaceous glands, and glands of Zeis
Zonulae adherens
belt desmosomes
they are specialized adherens junctions between cells. Their main role is in mechanical adhesion.
Zonulae occludens
Tight junctions
They form a special junction between cells such that the passage of molecules and ions through the space between plasma membranes of adjacent cells is blocked, so materials must actually enter the cell
Desmosomes
link two cells together
Hemidesmosomes
attach one cell to the extracellular matrix.
Goldmann applanation tonometry diameter of flattening
diameter of flattening is 3.06mm
which is based on counterbalancing the corneal resistance and the capillary attraction of tears for the tonometer head.
suspensory ligament of Lockwood
Mnemonic: chess
double check double inferior
The suspensory ligament of Lockwood forms a hammock-like support for the globe. It is composed of:
-the sheath of inferior rectus
-the medial check ligament
-the lateral check ligament
-sheath of inferior oblique
Strong convex lens (distortion)
pin-cushion effect
strong concave lens (distortion)
barrel effect
inferior oblique inserts on which quadrant of the globe:
Posterolateral quadrant
The inferior oblique inserts on the posterolateral quadrant, mostly below the horizontal.
Adrenergic agonists cause:
Adrenergic agonists cause:
-mydriasis
-ciliary muscle relaxation
-increased aqueous formation (though selective alpha-2 stimulation will reduce formation)
-increased aqueous outflow
-constriction of conjunctival and episcleral vessels
-contraction of Muller’s muscle
Neurofibromatosis Type 1 is associated with
meningioma, glioma and phaeochromocytoma
Neurofibromatosis Type 2 is associated with
bilateral acoustic neuroma
corneal stroma: collagen
Type I collagen
lateral geniculate nucleus consists of how many laminae or cell layers:
6
The LGN consists of six laminae or cell layers.
Corneal crystalline deposits are a side-effect of which topical medication?
Ciprofloxacin-induced corneal crystalline precipitates
Prolonged use of ciprofloxacin may cause corneal crystalline deposits. These are probably due to precipitation of drug, which requires low pH for solubility.
Schlemm’s canal is lined by
Schlemm’s canal is lined by a single layer of non-fenestrated endothelium joined by tight junctions
Drainage canal of Schlemm is facilitated by micropinocytic vescicles which coalesce to form giant vacuoles within the endothelial cells.
Ultrasound A-scan have in a phakic eye? peak (5)
There are five A-scan peaks in a phakic eye:
1.corneal surface
2.lens anterior surface
3.lens posterior surface
4.ILM of the retina
5.sclera
cerebrospinal fluid vs blood
higher conc of Chloride and H+
Almost all constituents of CSF are found in lower concentration than that of blood with the exception of Chloride and H+, which are higher. Thus, the pH and the PO2 of the CSF are lower than that of the arterial blood. Protein is lower in the CSF (in fact it is almost absent in the normal CSF). The glucose in CSF is 2/3 that of the blood.
Sclera collagen
Type 1
The sclera is composed mainly of Type 1 collagen.
CT imaging in thyroid eye disease?
Fusiform muscle enlargement with sparing of tendons
Aqueous humour vs plasma
More acidic, more ascorbate, less protein
Compared with plasma, aqueous is slightly hypertonic and acidic. Aqueous has a marked excess of ascorbate (15 times greater than that of arterial plasma) and a marked deficit of protein (0.2% in aqueous as compared to 7% in plasma
Caruncle is supplied by
innervated by the infratrochlear nerve
superior medial palpebral arteries
Facial nerve mnemonic
Two zebras bite my cake
To Zanzibar by my car
Temporal, Zygomatic, Buccal, Marginal mandibular and Cervical branches.
Southern Blotting:
Southern blotting is a technique for analyzing DNA.
The steps are as follows:
1.restriction endonucleases cut human DNA into fragments
2.fragments are separated by gel electrophoresis
3.the fragments are denatured to single strands and blotted on nitrocellulose
4.specific radio-isotope labeled DNA probes are used to bind complementary strands on the blotted fragments
abducens nerve arterial relation
The sixth cranial nerve is pinned down near to its exit from the pons by the anterior inferior cerebellar artery.
goblet cells on the tarsal conjunctiva are called
Henle’s crypts
goblet cells on the bulbar conjunctiva nasal to the limbus are called
Manz’s glands
common cause of corneal verticallata (vortex keratopathy)
amiodarone
inferior oblique muscle originates
Just lateral to the nasolacrimal canal
The inferior oblique muscle has its origin on the maxillary bone just posterior to the inferior medial orbital rim and lateral to the nasolacrimal canal.
posterior pigmented iris epithelium is a continuation
non-pigmented epithelium of the ciliary body
anterior iris epithelial layer is a continuation of
anterior iris epithelial layer is a continuation of the pigmented epithelium of the ciliary body
Amiodarone is commonly associated with which ocular side-effect:
Amiodarone can commonly cause corneal opacification known as vortex keratopathy
hamartoma
A hamartoma is comprised of tissue elements normally found at that site
choristoma
A choristoma is comprised of normal tissue in an abnormal location (e.g. a dermoid).
What is the scleral spur?
This is an anterior protrusion of the sclera which marks the attachment of the ciliary body’s longitudinal fibres.
What are the 3 fundamental properties of lasers?
Monochromaticity
coherency
Collimation
How does sodium fluorescence dye work?
It absorbs blue light and emits yellow green light which is detected by a fundus camera with cobalt blue excitation and yellow green barrier filters
mutton fat KPs
are formed by macrophage
There are five hormones which counteract the hypoglycemic effect of insulin:
glucagon
cortisol
growth hormone
adrenaline
noradrenaline
Which is the only extraocular muscle not to originate at the orbital apex:
the inferior oblique
The inferior oblique is the only extrocular muscle to originate outside the orbital apex. It originates behind the orbital margin lateral to the nasolacrimal duct and passes beneath the inferior rectus to insert on the sclera between the inferior rectus and the lateral rectus; with the posterior margin of the insertion corresponding to a point 2mm below and 2mm lateral to the macula.
mechanism Cyclosporin and tacrolimus
decrease levels of IL-2.
insert into the lateral tubercle of Whitnall (3)
suspensory ligament of eyeball
lateral canthal tendon
check ligament of eyeball
Ironically DOES NOT INSERT AT WHITNALLS TUBERCLE Whitnall’s ligament inserts 10 mm above the tubercle of Whitnall.
Whitnall’s ligament inserts how many cm, where?
10 mm above the tubercle of Whitnall.
signal modulation retina cells
Amacrine cells, horizontal cells
Bipolar cells function
Bipolar cells serve as a connector or intermediary between the photoreceptor and the ganglion cells
Muller cells are glial cells function
Muller cells are glial cells and perform a supportive role both structurally and nutritionally.
Muller cells are glial cells function
Muller cells are glial cells and perform a supportive role both structurally and nutritionally.
Muller cells are glial cells function
Muller cells are glial cells and perform a supportive role both structurally and nutritionally.
Grey line
Histology of the eyelid showing the grey line or mucocutaneous junction
The grey line represents the transition zone (mucocutaneous junction) between the outer keratinised squamous epithelium of the lid skin and the stratified columnar epithelium of the tarsal conjunctiva.
Ratio of nerve fibers to eye muscle fibres in the extraocular muscle is
1:3 to 1:10
Ocular motor neuromuscular units are small, with each nerve fibre supplying 3 to 10 muscle fibres apiece (compared with 1000 or more muscle fibres in the tibialis anterior). There are two main groups of motor units:
motor neurons that form single ‘en plaque’ endings and innervate twitch (fast) muscle fibres
motor neuros that form multiple small ‘en grappe’ endings along the length of tonic (slow) muscle fibres
basilar artery.
Anterior spinal arteries and the posterior inferior cerebellar arteries
dermoid
Limbal dermoids are characterised by:
choristoma: normal tissue in abnormal location
contains ectodermal elements: skin, hair, fat, and sebaceous glands
well-circumscribed, white-pale yellow, round lesion
flattest meridian of cornea is adjacent to the dermoid
no malignant potential
may be associated with Goldenhar’s syndrome
Note: dermoids contain ectodermal tissue; muscle is not expected in a dermoid.
Longitudinal, radial and circular (c) ciliary muscles
From the scleral side inward, the ciliary muscles are:
an external longitudinal (or meridional, or Brucke’s) - attaches to the scleral spur
a middle radial (or oblique) - attaches to corneoscleral trabeculae
internal circular (or Muller’s) - runs around ciliary body like a sphincter
optic nerve head which rim is the thinnest:
temporal
The normal healthy optic nerve rim has a characteristic configuration with the inferior rim broadest followed by the superior, nasal and temporal rims. This is remembered by the pneumonic the ISNT rule.
Sympathetic fibres to the iris synapse in the
superior cervical ganglion
posterior pituitary gland secretes:
oxytocin
ADH
ciliary processes: which epithelium actively secretes aqueous humour?
non-pigmented epithelium
Structures passing within the lateral wall of the cavernous sinus include:
CN III: oculomotor nerve
CN IV: trochlear nerve
CN V1: ophthalmic nerve
CN V2: maxillary nerve
CN VI passes through the cavernous sinus but not within the lateral wall. This potentially makes the 6th cranial nerve more susceptible to damage from conditions which infiltrate the cavernous sinus (e.g. thrombosis or infection).
Galilean formula
Peyepiece/Pobjective = - fobjective/feyepiece
immune hypersensitivity reactions: anaphylaxis, urticarial
Type I: anaphylaxis, urticarial
immune hypersensitivity reactions: haemolytic anaemia
Type II: haemolytic anaemia (antibody binding to antigen presented on the cell surface)
immune hypersensitivity reactions: Arthus reaction
Type III: Arthus reaction (immune complex mediated)
immune hypersensitivity reactions: Mantoux and contact dermatitis
Type IV: Mantoux and contact dermatitis (cell-mediated)
Coats disease:
The vascular abnormality in Coats disease is the result of an abnormal endothelium in arterioles and venules. This causes massive leakage of lipid-rich plasma into the retina and the subretinal space.
glossopharyngeal nerve
9th cranial nerve (CN IX)
has sensory, motor, and parasympathetic functions. It originates from the medulla oblongata and terminates in the pharynx. lesion produce difficulty swallowing; impairment of taste over the posterior one-third of the tongue and palate ; an absent gag reflex; and dysfunction of the parotid gland.
Arteries and its branches supplies the lateral geniculate body:
The posterior cerebral artery supplies the LGN via its branches called the posterior choroidal arteries. The anterior choroidal artery, a branch of the internal carotid, also helps to supply the LGN.
Saccades are controlled by
Saccades are controlled by the contralateral frontal lobe.
Pursuit is controlled by
Pursuit is controlled by the ipsilateral parietal lobe.
Lamina lucida
basal lamina of the corneal epithelium, which is itself composed of two layers:
the lamina lucida: which is more superficial
the lamina densa: which is deeper
Ocular ultrasound is usually performed in the range of
8 to 15 MH
Higher frequencies give better resolution. Lower frequencies give better penetration.
ciliary ganglon is found between
optic nerve and the lateral rectus muscle
ciliary ganglon
It contains:
1.a parasympathetic ganglion which receives its parasympathetic preganglion fibres from the Edinger-Westphal nucleus and which supplies the sphincter papillae
2.sensory fibres leaving the posterior globe
3.sympathetic postganglionic fibres from the superior cervical sympathetic ganglion which supply the dilator pupillae
Note: sympathetic fibres supplying the dilator pupillae pass through both (1) the ciliary ganglion and the short ciliary nerves and (2) the nasociliary nerve and the long ciliary nerve to reach the dilator pupillae.
The choroid is composed of: how many layers
The choroid is composed of 5 layers:
Bruch’s membrane
Choriocapillaris
Sattler’s layer
Haller’s layer
the suprachoroid
Koeppe, Richardson, Barkan, Wurst and Swan-Jacob lenses. gonioscopy
Direct lenses
Goldmann, Zeiss, Posner and Sussman lenses. gonioscopy
Indirect lenses
double letter except koeppe
features of malignant tumours
Cellular and nuclear pleomorphism
Nuclear hyperchromatism.
There is a decrease in the cytoplasmic: nuclear ratio.
positive pathergy test
A positive pathergy test is the formation of any of the following:
- papule
- pustule
- ulceration
within a few days of pricking the skin with a sterile hypodermic needle. There are no specific size requirements for a positive Pathergy test.
Type I hypersensitivity
reaction mediated by IgE antibodies
Type II hypersensitivity
cytotoxic reaction mediated by IgG or IgM antibodies
Type III hypersensitivity
reaction mediated by immune complexes
Type IV hypersensitivity
delayed reaction mediated by cellular response
Class II MHC proteins are found
macrophages, B cells, dendritic cells of the spleen, Langerhans cells of the skin
halitosis and hypertrophy of gingival tissue (3 drugs)
- Cyclosporin A (which produces the most hyperplasia),
- Nifedipine
- Phenytoin
Trachoma stages
Stage I: involvement of the conjunctival stroma
Stage II: involvement of the cornea with pannus formation
Stage III: fibrous replacement of inflamed tissue
Stage IV: contraction with entropion and trichiasis.
Orbital wall which is most likely to be involved in a blow-out fracture is:
The floor
The medial orbital wall is the thinnest orbital wall but the orbital floor is the most likely to be involved in blow-out fractures
Back vertex distance formula
Fnew = Fcurrent/(1-dFcurrent)
Fnew = power of new lens (e.g. contact lens)
Fcurrent = power of current lens
d = vertex distance measured in meters
Layer II and III
project to the secondary visual cortex
Layer IV
receives fibres from the macula
Layer V
projects to the superior colliculus
Layer VI
projects to the LGN
Translation is controlled by:
peptidyl transferase
rod photoreceptors myoid
The inner half of the inner segment
is known as the myoid
myoid contains numerous organelles including Golgi apparatus and smooth ER
rod photoreceptors ellipsoid
outer half of the inner segment
is known as the ellipsoid
the ellipsoid contains numerous mitochondria
The superior oblique inserts on which quadrant of the globe:
posterosuperior
The superior oblique inserts on the posterosuperior quadrant of the globe.
supporting glial cells of the retina are:
Muller cells
rods (Maximal spectral sensitivity)
Maximal spectral sensitivity of the rods is 496 nm.
Parinaud’s oculoglandular syndrome caused by
Bartonella
Sympathetic pathway: First order
Hypothalamus along the brainstem to synapse in the ciliospinal center of Budge
Sympathetic pathway: Second order
Centre of Budge to superior cervical ganglion
Sympathetic pathway: Third order
Superior cervical ganglion, travels along the carotid plexus, branches join the ophthalmic division of the trigeminal nerve and pass through the ciliary ganglion to the nasociliary and short ciliary nerves
Diagnosing sarcoid? (2)
Serum ACE + Lysozyme
core proteins of gap junctions
connexins
Thromboxane A2:
Thromboxane A2 is produced by platelets. It plays an important role in platelet aggregation and its action is mediated via cAMP. It also causes vasoconstriction. Prostacyclin opposes the action of Thromboxane A2 and inhibits platelet aggregation
primary metabolic substrate of the cornea is:
glucose
Hamartomas
haemangiomas and lymphangiomas.
fourth cranial nerve nucleus resides in:
the midbrain
done in the polymerase chain reaction?
DNA amplification
inner capillary plexus of the retina is contained in:
ganglion cell layer
extraocular muscle with the shortest length of tendon is the:
inferior oblique
T lymphocytes predominate in
paracortex
B lymphocytes predominate in
follicles of the cortex
plasma cells are found chiefly in
medulla
dK value refers to (in contact lens)
oxygen permeability of the contact tens
A change in the radius of corneal curvature of 0.1 mm produces a change in refraction of how many diopters in contact lens
0.5 dioptres
amiodarone and phenothiazine cause what cataract?
stellate cataracts
Direct-acting parasympathomimetics examples
pilocarpine and carbachol
Which is the largest extraocular muscle:
medial rectus
structure of basement membranes
Laminin
protein analysis
Western blotting, immunoprecipitation and ELISA
lateral geniculate body (LGN): cross fibres
1, 4 and 6
lateral geniculate body (LGN): uncrossed fibres
2, 3 and 5
subretinal space occurs between:
the RPE and the neural retina
brimonidine (alphagan) dual action and class
Alpha-2 adrenergic agonists
brimonidine work by a dual mechanism, decreasing aqueous production and increasing outflow
retinal pigment epithelium is:
The RPE is a monolayer of columnar/cuboidal epithelial cells.
Chlamydia trachomatis (Subtype)
Subtypes A to C cause trachoma (eye to eye contact)
while subtypes D to K cause paratrachoma (sexually transmitted).
adult lens diameter
10mm
lens curvature, which side is more curved
Anterior
anterior radius of curvature is greater than the posterior curvature
firm point of attachment between the choroid and sclera
vortex veins
blind spot on visual fields how many degree
15
blind spot on visual fields (produced by the optic nerve) is 15 degrees from fixation, corresponding with the displacement of the optic nerve from the fovea.
Astrocytic hamartomas within the retina:
Tuberous sclerosis
synoptophore
Equipment which can be used to assess the angle of deviation and binocular potential at a theoretical distance fixation.
acanthamoeba corneal biopsy
double-walled cyst form or the trophozoite is seen in corneal biopsy
CMV retinitis causes
Causes a necrotizing retinitis involving all retinal layers. Intranuclear inclusion bodies may be found
Drusen is situated
Drusen is situated between the basement membrane of the RPE and the Bruch’s membrane.
Corneal guttatae
small excrescences of Descemet’s membrane
Corneal guttatae are the hallmark of Fuchs dystrophy and represent the earliest sign of the disease. They are seen clinically on the slit lamp where they are best observed by retroillumination. Histologically they represent small excrescences of Descemet’s membrane. These are typically exophytic protruding posteriorly into the anterior chamber.
primary visual cortex (area)
area 17
angle of minimum deviation of a prism occurs when:
angle of incidence equals the angle of emergence
