Ophthalmology

Question 1

What area of the eye has the highest visual acuity?

Answer 1

Fovea as it contains over half the fibres in the optic nerve

Question 2

Where is aqueous humour of the eye produced?

Answer 2

Ciliary body in posterior chamber

Question 3

What eye condition can increased aqueous humour lead to?

Answer 3

Glaucoma due to increased eye pressure

Question 4

The is a thin tissue layer containing blood vessels to the eye

Answer 4

Choroid

Question 5

How is near vision achieved?

Answer 5

Contraction of ciliary muscle → relaxes lens (more convex)

Question 6

How is distance vision achieved?

Answer 6

Relaxattion of ciliary muscle → flatttens lens

Question 7

A 26 year old obese women presents with HA, nausea, vomiting and visual changes. You look into her eye and you see this. Her MRI has no abnormalities. What is the most likely diagnosis?

Answer 7

Idiopathic intracranial hypertension (pseudotumor cerebri)

Question 8

A patient presents with extreme eye pain and vision loss that occurred rapidly. What drug should you definitely not use?

Answer 8

Epinephrine

• Likely acute closed angle glaucoma
• Epinephrine leads to mydriasis, which further closes the angle

Question 9

What is the immediate treatment for uveitis?

Answer 9

Steroids

Question 10

signalling is necessary for fibre differentiation in the lens

Answer 10

FGF

Question 11

What cells do receptor cells (rods and cones) synapse onto?

Answer 11

Bipolar cells

Question 12

What cells do bipolar cells synapse onto?

Answer 12

Ganglion cells, which then make up optic nerve fibres

Question 13

What are the 4 subcortical regions to which the optic nerve ganglion cells project?

Answer 13

• Superior colliculus (optic tectum) in midbrain
• Lateral geniculate nucleus
• Pretectum
• Hypothalamus

Question 14

What is the distribution of rods and cones throughout the retina?

Answer 14

• Rods: predominate periphery, numbers decreasing towards the macula
• Cones: increase towards the macula, at the fovea only cones are present

Question 15

In the fovea where visual acuity is the highest, is the convergence low or high?

Answer 15

Low as 1:1 ratio of cones:bipolar cells

Question 16

What cranial nerve is a tract of the diencephalon?

Answer 16

Optic (CN III)

Question 17

What cells produce myelin that covers the optic nerves?

Answer 17

Oligodendrocytes

Question 18

Where do fibres carrying the upper part of the visual field run?

Answer 18

Temporal lobe via Myers loop

Upper visual field to lower part of retina (green)

Question 19

Where do fibres carrying the lower part of the visual field run?

Answer 19

Parietal lobe

Question 20

Broadly, what are the layers and cells of the retina?

Answer 20

• Ganglion cells (magnocellular, parvocellular)
• Photoreceptors (rods, cones)
• Pigment epithelium

Question 21

Where does the main visual pathway terminate?

Answer 21

Thalamus

Then projects to the cerebral cortex via the optic radiation

Question 22

What area of the eye is affected in macular degeneration?

Answer 22

Central retina: central death of pigment epithelium

Question 23

What kind of macular degeneration is neovascular?

Answer 23

Wet macular degeneration

Question 24

Which condition would you see drusen, and disruption of the retinal pigment epithelium seen as pigmentary changes?

Answer 24

Macular degeneration

Question 25

What condition is defined by **detachment of pigment epithelium and photoreceptors?**

Answer 25

Retinal detachment

Question 26

Where is the lateral geniculate nucleus located?

Answer 26

Thalamus

Question 27

What are the three big areas of reorganisations that occur in the lateral geniculate nuclus?

Answer 27

* **Streams**: motion (magnocellular) and colour (parvocellular) * **Topography**: central or peripheral visual field (contralateral) * **Laterality**: which eye is the stimulus from (nasal crosses, temporal remains on same side)

Question 28

To where does the lateral geniculate nucleus project information?

Answer 28

Primary visual cortex

Question 29

Which sinus has a strong relationship with the optic nerve?

Answer 29

Ethmoid sinus

Question 30

What is the cause of papilledema?

Answer 30

Increased pressure around the optic nerve

Question 31

Where is the suprachiasmic nucleus located and what is it responsible for?

Answer 31

Hypothalamus Circadian rhythm

Question 32

Where is the pretectum located and what is it responsible for?

Answer 32

**Midbrain** **Pupillary reflex:** afferent CN II and efferent parasympathetic fibres of CN III via Edinger Westphal nucleus

Question 33

Where is the **superior colliculus** and what is its function?

Answer 33

**Midbrain** **Visual reflex:** reflex movements of the eyes, head and neck to orientate head away from danger or towards objects of interest

Question 34

What is the nerve supply of the **cornea**?

Answer 34

Trigeminal (CN V1)

Question 35

What does normal tear flow depend on? (4)

Answer 35

* Lacrimal gland secretion * External eye/ocular surface * Lid function as lacrimal “pump” * Lacrimal drainage apparatus

Question 36

Impairment of what muscle is responsible for the eye droop in Horner's syndrome?

Answer 36

**Muller's muscle** (off levator palpebrae) Sympathetic innervation to assist in raising eyelid

Question 37

Describe the process of the pupillary light reflex

Answer 37

1) light enters the eye 2) sensory information is carried to the **ipsilateral pretectal area** 3) interneuron relays information from **pretectal area to ipsilateral and contralateral Edinger-Westphal nucleus** 4) Edinger Westphal nucleus send **preganglionic parasympathetics to the ciliary ganglion** 5) clilary ganglion send **postganglionic parasympathetics to pupillary constrictor** to cause constriction

Question 38

What area is responsible for unconscious vision "blindsight"?

Answer 38

Superior colliculus

Question 40

What are the three layers of the sclera?

Answer 40

Outermost: **Episclera** (dense, fibrous CT) Middle: **Sclera proper** (collagen fibres) Inner: **Lamina fusca** (pigmented)

Question 41

What are the five layers of the cornea?

Answer 41

(Outer-inner) 1. Epithelial layer (rich in nocicepters) 2. Bowmans membrane 3. Stromal layer 4. Desments membrane 5. Endothelial layer (little bit of blood supply)

Question 42

What structures make up the vascular tunic (uvea) of the eye? (3)

Answer 42

* Choroid * Iris * Ciliary body: ciliaris (accomodation), ciliary process