Week 2 - E - Ophthamology 4 - Gradual vision loss causes

Question 1

What is the mnemonic to remember the causes of gradual vision loss?

Answer 1

C - cataracts

A - age related macular degeneration (dry)

R - refractive error

D - iabetetic retinopathy

I - inheritied diseases (retinitis pigmentosa)

G - glaucoma (open angle)

Access to clinical and

Non urgent

Question 2

Is gradual visual loss usually unilateral or bilateral?

Answer 2

Usually bilateral but can be unilateral often as well

Question 3

What is age related clouding of the lens known as?

Answer 3

This is cataracts

Question 4

How does cataracts present?

Answer 4

Gradual deterioration of vision in both eyes

Sight is blurred and worse in bright lights

Absent red reflexes

Question 5

Why is it important to check red reflexes in children?

Answer 5

Because children can have congenital cataracts if there had been an intrauterine infection

Question 6

What is the most common intrauterine infection causing congenital cataracts?

Answer 6

Rubella

Question 7

What is the most common type of cataract and what happens?

Answer 7

Nuclear cataracts

gradual hardening and yellowing of the central zone of the lens, also known as the nucleus.

Over time, this hardening and yellowing will expand to the other layers of the lens

Question 8

What is the treatment of cataracts?

Answer 8

Surgical removal of lens and replacement with intraocular lens

Question 9

Gradual distortion of central vision and an abnormal macula on examination What is this?

Answer 9

This is dry age related macular degeneration

Question 10

What are the build up of waste products below the retinal pigment epithelium in dry ARMD known as?

Answer 10

Drusen depsoits - these are a build up of fat showing as yellow on fundoscopy

Question 11

What is the treatment for dry age related macular degeneration as there is no cure?

Answer 11

Prevention is the best - stop smoking

The use of magnifying glasses to help with vision

Antioxidant vitamins and mineral supplements are also advised - vitamin A, C, E and zinc

Question 12

Refractive error is when the lens shape of the eye is not correct and therefore rays to not focus on the retina What are the four types of refractive error?

Answer 12

Myopia - near sightedness

Hypermetropia - far sightedness

Astigmatism - irregular corneal curvature

Presbyopia

Question 13

What is presbyopia?

Answer 13

Presbyopia is an ageing condition of the eyes where the lens hardens and is therefore unable to fatten for near sight objects as the ray focus behind the eyes (age related long sightedness causing loss of accomodation)

Question 14

What does it mean to have loss of accomodation in presbyopia?

Answer 14

This means when changing from looking at a distant object to a close one, the lens is too hard and wont change in size to accommodate causing blurred vision

Question 15

What type of lens is required to fix myopic eyes? Describe what happens to the rays in myopia?

Answer 15

require a concave lens to diverge the rays as the rays focus in front of the retina in myopia

Question 16

What type of lens is required in hypermetropia? What type of lens is required in astigmatism?

Answer 16

In hypermetropia - a convex lens to increase refraction so light rays can focus on the retina

In astigmatism - a cylindrical lens is reuired

Question 17

What happens in astigmatism?

Answer 17

There is irregular curvature of the cornea causing the light to not focus on one pooint but instead can be refracted in front and / or behind the retina

This causes the image to be blurring both longitudinally and vertically

Question 18

What are the two names for the ligaments attaching the ciliary body to the lens of the eye?

Answer 18

Zonules of Zinn

Suspensory ligaments of the lens

Question 19

What causes the lens to shorten and fatten in a normal circumstances? What type of sight is this in?

Answer 19

This is due to ciliary muscles contracting, relaxing the suspensory ligaments of the lens allowing the lens to shorten and fatten

this is for seeing near objects

Question 20

What causes the lens to elongate and narrow? What type of sight is this in?

Answer 20

This is when the ciliary muscles relax, the suspensory ligaments of the lens contract causing the lens to elongate

This is for far sightedness

Question 21

What is the nerve supply to the ciliary muscles?

Answer 21

Parasympathetic nerve supply from the oculomotor nerve (CN III)

Question 22

What type of sight is acute angle closure glaucoma associated with?

Answer 22

Associated with perople who have long sight - wide lens can close uveoscleral tract

Question 23

Is the prescription for long or short sighted people a negative dioptre?

Answer 23

Near sighted people have a negative dioptre

Far sighted people have a positive dioptre

Question 24

Poor diabetic control can lead to diabetic retinopathy due to the hyperglycaemia What are the signs of non proliferative diabetic retinopathy?

Answer 24

Cotton wool patches hard exudates

Microaneusyms (dot/blot hemorrhages)

Question 25

What is the main sign of proliferative diabetic retinopathy?

Answer 25

Neovasuclarisation of the disc and retina

Question 26

What can happen due to the neovasuclarisation?

Answer 26

The vessels are weak and can burst causing vitreous haemorrhage and therefore affecting vision due to floaters

Question 27

What are the cotton wool spots in diabetic retinopathy a sign of?

Answer 27

These are signs of areas of ischaemia

Question 28

What is the treatment of diabetic retinopathy?

Answer 28

Usually try Pan retinal photocoagulation (PRP)

to stop the vessels leaking and reduces oxygen requirment therefore stopping formation of new blood vessels

Patient must get hyperglycaemia under control

Question 29

What are the potential side effects of pan retinal photocoagulation?

Answer 29

• Decreased night vision and dark adaptation
• Decreased visual field / peripheral vision
• Peripheral and night vision mainly affected as rods are burnt
• Central vision usually less affected than peripheral

Question 30

in both CRVO and Proliferative diabetic retinopathy, vessel growth can occur in the iris due to VEGF, What is this known as?

Answer 30

Rubeosis iridis is a medical condition of the iris of the eye in which new abnormal blood vessels (i.e. neovascularization) are found on the surface of the iris.

Question 31

What is an example of inherited condition hat leads to loss of vision and blindness?

Answer 31

Retinitis pigmentosa intially due to the progressive degeneration of the rod photoreceptor cells in the retina. and later followed by loss of cone receptors

Question 32

What are the features of retintiis pigmentosa? What is seen on fundoscopy in retinitis pigmentosa?

Answer 32

Features night blindness is often the initial sign tunnel vision due to loss of the peripheral retina

Fundoscopy: black bone spicule-shaped pigmentation in the peripheral retina, mottling of the retinal pigment epithelium

Question 33

To drive a car You must be able to read (with glasses or contact lenses, if necessary) a car number plate made after 1 September 2001 from 20 metres. What is the minimal visual acuity that you must have in order to drive a car?

Answer 33

You must also meet the minimum eyesight standard for driving by having a visual acuity of at least decimal 6/12 in one of the eyes (can read from 6 metres away what somebody with perfect vision can read from 12 metres away)

Question 34

What standards must both eyes meet for a lorry and bus drivers?

Answer 34

You must have a visual acuity at least 6/7.5 (basically 6/6 vision on snellen) measured on the Snellen scale in your best eye and at least 6/60 on the Snellen scale in the other eye.