Introduction to Ophthalmology

Question 1

What is the average axial length?

Answer 1

23mm

Question 2

What occurs in refractive errors?

Answer 2

When the image appear in front of or behind the retina, so a shorter or longer refractive error. Myopia and hyperopia respectively.

Question 3

What can causes double vision when it comes to musculature?

Answer 3

If there is misalignment of the visual axis caused by misalignment of the extraocular muscles.

Question 4

What is exophthalmos?

Answer 4

The bulging and protruding of the eyeballs, can be caused by a tumour or inflammation (in graves) of the orbit.

Question 5

What is enophthalmos?

Answer 5

The sinking in of the eyeballs and eye movement restriction, can be caused by an orbital fracture and affected movement by restricting a muscle if it affects a nerve.

Question 6

When does facial development occur?

Answer 6

4-8 weeks.

Question 7

What is a coloboma?

Answer 7

Eye abnormality after birth, missing pieces of tissue e.g. iris coloboma is when the iris doesn’t fuse properly so the pupil connects to the bottom of the iris. Can also be retinal.

Question 8

What are the visual milestones within the first year of life?

Answer 8

1. Birth - Can see high contrast e.g. checkboard, can’t focus on targets further than 20-30cm. They cannot move eyes between two images.
2. 3 months - can fix and follow
3. 5-8 months - good colour vision, start crawling to reach objects
4. 9m-1yr - spot object nearby (2-3mm), watch and imitate faces and search for objects being hidden

Question 9

What are the main visual milestones in the first 7 years?

Answer 9

2 yrs - complete myelinisation of the optic nerve and acuity is normal
2-5 yrs - brain sensory processing is nearly adult
3 yrs - retinal tissue mature, can complete form board based on visual memory, simple puzzle, crude circle and put pegs into holes
5-7 yrs - functional development of brain substrates for perceiving complex visual scenes

Question 10

How is blindness defined? (no legal definition)

Answer 10

Blind enough that they cannot do work for which eyesight is essential.

1. A visual acuity of 3/60 to 6/60 with full field.
2. 6/24 with restricted visual field, opacities or aphakia
3. 6/18 or better with gross field defect (hemianopia) or constriction of field (glaucoma)

Question 11

What are the most common causes of blindness?

Answer 11

Cataracts, incorrect lenses or surgery

Question 12

What is trachoma?

Answer 12

An infection that causes scarring of the conjunctiva. It rotates the eyelashes and the eyelids within which scars the cornea.
It can be spread from person to person.

Question 13

How to prevent trachoma to prevent blindness?

Answer 13

Surgery
Antibiotics
Face washing
Education and environmental impacts (safe removal of faeces as travel on flies)

Question 14

What is age related macular degeneration? (AMD)

Answer 14

The retina develops changes, bleeding and scarring, it prevent driving, reading and facial recognition.
Leading cause of blindness in the UK.
Wet type is accelerated.

Question 15

How do we prevent AMD?

Answer 15

Avoiding cigarettes
Good nutrition
Good cardiovascular health

Question 16

How do we treat wet AMD

Answer 16

Anti-VegF intravitreally

Question 17

What is diabetic retinopathy?

Answer 17

Microvascular complication that can be prevented with good sugar control.

Question 18

How do we treat diabetic retinopathy?

Answer 18

Used to be laser photocoagulation but can be destructive and only stops progression.
Anti-VegF is better but there is a problem with supply and staffing.

Question 19

What is glaucoma?

Answer 19

A progressive optic neuropathy characterised by optic disc changes and commensurate visual field defects. 2nd most common cause of blindness UK.
Usually associated with high intraocular pressure that erodes the nerve (not all)

Question 20

What is cataracts?

Answer 20

Clouding of the lens.

Question 21

How do we treat cataracts?

Answer 21

Lens implant

Question 22

What occurs to cause orbital inflammation in thyroid diseases (graves)

Answer 22

Immunological cross-reactivity of antibodies targeting the thyroid and the orbit. IGF1-R and TSHR. Causing adipogenesis and hyaluron deposition in the muscles.

Question 23

How can you treat graves affecting the eyes?

Answer 23

Mild - lubricants and other simple measures
Moderate - immunosuppression and surgery
Sight-threatening - immediate treatment

Question 24

What might a change in dilation of pupils indicate?

Answer 24

An aneurysm, the posterior communicating artery can have a non-pupil sparing aneurysm

Question 25

What may signify temporal arteritis?

Answer 25

Acute loss of vision, headaches, pain on jaw movements e.g. chewing, sore scalp.

This is sight-threatening