Ophthalmology - gradual deterioration of vision Flashcards
(41 cards)
1
Q
defintion
cataracts
A
progressively opaque eye lens which reduces the light entering the eye and visual acuity
2
Q
role of the lens
cataracts
A
- focus light on the retina
- held in place by suspensory ligaments attached to the ciliary body
- ciliary body contracts and relaxes to change the shape of the lens
- ciliary body contracts - releases tension on suspensory ligaments - lens thickens
- ciliary body relaxes - suspensory ligaments tense - lens narrows
- lens has no blood supply - nourished by the aqueous humour
3
Q
causes
cataracts
A
- age related - most common
- traumatic - blunt/penetrating injury
- metabolic - uncontrolled DM, galactosaemia, wilson disease
- congential
4
Q
age related - patho
cataracts
A
multifactorial:
- compaction and stiffening of lens material as new layers continue to proliferate
- abnormal changes in lens proteins leading to loss of transparency
- pigmentation of lens proteins
- changes in the ionic components of the lens
5
Q
presentation
cataracts
A
- blurred vision at distance or near
- glare (halos or streaks around the lights)
- difficulty seeing in low light situations
- loss of ability to discern colours
- increasing shortsightedness or change in refractive status
6
Q
investigations
cataracts
A
- visual acuity
- opthalmoscopy - normal fundus and optic nerve
- slit-lamp - visible cataract (cloudy or opaque, hazy yellow/brown)
7
Q
risk factors
cataracts
A
- uncontrolled diabetes
- steroid use
- UV exposure
- smoking
- ocular disease like retinitis pigmentosa or uveitis
- ocular trauma
- prior ocular surgery
- genetic predisposition
- radiation or chemo induced
8
Q
Mx - non-surgical
cataracts
A
slow development:
- balanced diet
- prevent excessive UV exposure by wearing sunglasses
- avoid injuries by wearing protective eyewear
- diabetic - control blood sugars
temporarily improve visual function:
- careful refraction
- pharmacological dilation
- increased lighting
- use of magnifiers for near work
9
Q
Mx - surgical, complication
cataracts
A
- cataracts surgery:
- drilling and breaking the lense to pieces
- removing the pieces
- implanting artificial lens
- day case under local anaesthetic
- complications
- endophthalmitis
- retinal detachment
- posterior capsule rupture
- posterior capsule opacification - thickening of the lens capsule
10
Q
epidaemiology
ARMD
A
- most common cause of blindness in the UK
- more common with advancing age and females
11
Q
definition
ARMD
A
degeneration of retinal photoreceptors (usually bilateral) that results in the formation of drusen which can be seen on fundoscopy and retinal photography
12
Q
macula role, layers
ARMD
A
- macula is in the centre of the retina - generates high-definition colour vision in the central visual field. 4 layers:
- photoreceptors (towards the surface)
- retinal pigment epithelium
- bruch’s membrane
- choroid layer (at the base) - contains the blood vessels that supply the macula
13
Q
RFx
ARMD
A
- advancing age
- smoking
- family history
- hypertension
- poor diet
- obesity
14
Q
classification
ARMD
A
Dry - non-neovascular/atrophic
- 90% of cases
- characterised by drusen
wet - neovascular/exudative
- 10%
- choroidal neovascularisation
- leakage of serous fluid and blood
- worst prognosis
15
Q
dry patho
ARMD
A
→ Drusen:
yellowish deposits of proteins and lipids between the retinal pigment epithelium and Bruch’s membrane
→ atrophy of the retinal pigment epithelium
→ degeneration of photoreceptors
16
Q
wet patho
ARMD
A
→ new vessels develop from the choroid layer and grow into the retina
- can leak fluid or blood causing oedema and faster vision loss
- vascular endothelial growth factor (VEGF) stimulates the development of new vessels
17
Q
symptoms
ARMD
A
subacute onset visual loss:
- reduced acuity, especially near
- difficulties adapting in the dark
- fluctuation in vision
- photopsia - perception of flickering or flashing lights
- glare
- charles-Bonnet syndrome
18
Q
signs
ARMD
A
- distortion of line perception on Amsler grid testing
- fundoscopy - drusen: yellow areas of pigment deposition in the macular area
- wet - demarcated red patches which represent intra-retinal or sub-retinal fluid leakage or haemorrhage
19
Q
investigations
ARMD
A
- slit lamp - visualise retina
- colour fundus photography
- fluerescein angiography - if wet suspected
- OCT
20
Q
Mx
ARMD
A
Dry
- lifestyle - smoking, diet (omega-3s)
- vitamins - beta-carotene, vitamines A,C,E and zinc
Wet
- anti-VEGF injections
- laser photocoagulation if new vessels
21
Q
definition
primary open angle glaucoma
A
optic nerve damage caused by a rise in intraocular pressure
- caused by a blockage in aqueous humour
22
Q
normal IOP
primary open angle glaucoma
A
10-21mmHg
23
Q
patho
primary open angle glaucoma
A
- gradual increase in resistance to flow through trabecular meshwork
- trabecular meshwork becomes inefficient over time
- pressure slowly builds in the eye
- causes cupping of the optic disc
24
Q
RFs
primary open angle glaucoma
A
- increasing age
- family history
- black othnic origin
- myopia
25
# presentation
primary open angle glaucoma
- gradual onset tunnel vision
can also cause:
- fluctuation pain
- headaches
- blurred vision
- halos around lights
26
# how to measure IOP
primary open angle glaucoma
- non-contact tonometry
- goldmann applanation tonometry
27
# Ix
primary open angle glaucoma
- goldmann applanation tonometry
- slit lap for cup-disk ratio
- visual fields
- gonioscopy - angle between iris and cornea
- contral corneal thickness assessment
28
# Mx
primary open angle glaucoma
1. 360 degrees laser trabeculoplasty -> improve drainage, may need second procedure
2. eye drops:
-> prostoglandin analogue eye drops e.g. latanoprost - increases uveosclera outflow
-> beta-blocker drops e.g. timolol - reduce production of aqueous humour
-> carbonic anhydrase inhibitors e.g. acetazolomide - reduce production of aqueous humour
3. trabeculectomy surgery - if other treatments are ineffective
-> creates a new channel
29
# defintion
diabetic eye disease
damage to the retinal blood vessels due to prolonged high blood sugar levels
30
# RFs
diabetic eye disease
- duration of diabetes
- glycaemic control
- hypertension
- dyslipidaemia
- obesity
- pregnancy
31
# patho
diabetic eye disease
1. **Chronic hyperglycaemia** damages retinal small vessels and endothelial cells.
2. **Increased vascular permeability** causes leaking vessels → **blot haemorrhages** and hard exudates.
3. **Vessel wall damage** leads to **microaneurysms** and venous beading.
4. **White cell adhesion** to capillary walls causes occlusion → **cotton wool spots**.
IRMA (intraretinal microvascular abnormalities) form as shunts between arteries and veins.
Neovascularisation is triggered by growth factors → formation of new, fragile blood vessels.
32
# 3 types
diabetic eye disease
1. Background – microaneurysms, retinal haemorrhages, hard exudates and cotton wool spots
2. Pre-proliferative – venous beading, multiple blot haemorrhages and intraretinal microvascular abnormality (IMRA)
3. Proliferative – neovascularisation and vitreous haemorrhage
33
# Ix
diabetic eye disease
1. OCT
2. fundus fluorescein angiography
3. slit lamp + fundoscopy
34
# non-proliferative Mx
diabetic eye disease
- diabetic control
- annual screening
35
# pre-proliferative Mx
diabetic eye disease
4-6 month follow up with digital fundus colour photographs
36
# proliferative Mx
diabetic eye disease
- **Pan-retinal photocoagulation** (PRP) – extensive laser treatment across the retina to suppress new vessels
- **Anti-VEGF** medications by intravitreal injection
- Surgery (e.g., **vitrectomy**) may be required in severe disease
37
# complications
diabetic eye disease
- vision loss
- retinal detachment
- vitreous haemorrhage (bleeding in the vitreous humour)
- rubeosis iridis (new blood vessel formation in the iris) this can lead to neovascular glaucoma
- optic neuropathy
- cataracts
- retinal vein occlusion
38
# defintion, epidaemiology
Presbyopia
- irreversible loss of the accommodative ability of the eye due to ageing
- typically affects people around age 40-45 and progresses until the mid 50s
39
# causes
Presbyopia
primary cause is ageing. other factors:
- systemic disease (e.g. diabetes)
- medications (antihistamines, antidepressants)
- eye trauma
- occupational demands (prolonged near-work exposure)
40
# clinical features
Presbyopia
- gradual onset of blurred near vision
- difficulty reading small print
- eye strain and headaches
- need to hold objects at a greater distance to see clearly
- increased dependence on brighter light for reading
41
# Mx
Presbyopia
- corrective lenses
- contact lenses
- surgical options:
- refractive surgery
- presbyopia-correcting intraocular lenses in cataract surgery
