Intro to Opthamology

Question 1

What is the neuronal pathway for pupillary reflexes?

Answer 1

Parasympathetic Reflex for consensual and direct pupil constriction
Optic disc neural fibers – Optic nerve– optic chiasm– optic tract– pretectal areas (bilateral Midbrain)– Edinger-Westphal nucleus– Oculomotor n (preganglionic process)– ciliary ganglion– postganglionic process distributed with Ophthalmic division of Trigeminal n to sphincter pupillae

Question 2

What is the neuronal pathway for vision?

Answer 2

Optic disc neural fibers – optic nerve– optic chiasm (affected by pituitary tumour)– optic tract– Lateral geniculate nucleus (Thalamus) – optic radiations Sup visual field pass thru temporal lobe, inf thru parietal lobe (Baum’s and Meyer’s loops) – Occipital cortex

Question 3

What occurs in the accommodation pathway?

Answer 3

Parasympathetic response.

1. Pupil constriction via sphincter pupillae
2. adduction of the eyes with MR (Occulomotor n)
3. Ciliary muscles contract relaxing the zonular fibres causing the lens to take a rounded shape

Question 4

What is the Sympathetic pathway for pupil control?

Answer 4

Pupilodilator nucleus (Posterior Hypothalamus)– Cilliospinal centre of Budge– sympathetic chain– superior cervical ganglion – carotid plexus– Ophthalmic nerve– ciliary nerves– Dilator pupillae muscle

Question 5

Where is the blind spot located in a person’s visual field and their retina?

Answer 5

The blind spot corresponds to the optic disc location. therefore this is in the nasal retina and the temporal visual field.