Cataracts and macular degeneration Flashcards
(25 cards)
What is cataracts
the progressive opacification of the eye lens that reduces light entering the eye and impairs visual acuity.
What is the function of the lens in the eye?
To focus light on the retina.
How does the ciliary body change the shape of the lens?
- Contracts → reduces tension on suspensory ligaments → lens thickens
- Relaxes → increases tension on suspensory ligaments → lens narrows
When do congenital cataracts occur, and how are they screened for?
Before birth; screened with the red reflex test during the neonatal exam.
List 6 risk factors for cataracts.
- Increasing age (>60yrs)
- Smoking
- Alcohol
- female
- Diabetes
- long-term Steroids
- UV exposure
- Hypocalcaemia
What are the main symptoms of cataracts?
- Slow reduction in visual acuity
- Progressive blurring
- Faded colour vision
- Halos around lights
- Glare: lights appear brighter than usual
What is a key examination finding in cataracts?
Loss of the red reflex.
What investigations are used to diagnose cataracts, and what are their findings?
- Ophthalmoscopy (after pupil dilation): Normal fundus and optic nerve.
- Slit-lamp examination: Visible cataract.
How are cataracts managed
- early stages: conservative
- surgery: removing the lens, then implanting an artificial lens
- referall for surgery should be dependent on: visual impairment, quality of life and patient choice
Why might visual acuity remain reduced after cataract surgery?
Underlying pathology like macular degeneration or diabetic retinopathy may become evident.
What are the complications following cataract surgery?
- Posterior capsule opacification: Thickening of the lens capsule.
- Retinal detachment
- Posterior capsule rupture
- Endophthalmitis: Inflammation of the aqueous and/or vitreous humour.
What is Age-related Macular Degeneration (AMD)?
A progressive condition affecting the macula and the most common cause of blindness in the UK.
What is the macula and what is its function
- found in the centre of the retina
- provides high-definition, color vision in the central visual field.
What are the four layers of the macula?
- Choroid (contains blood vessels)
- Bruch’s membrane
- Retinal pigment epithelium
- Photoreceptors
What are the two types of age-related macular degeneration and their prevalence?
Dry (atrophic): 90% of cases
Wet (neovascular): 10% of cases
What are drusen, and what is their significance in age-related macular degeneration?
Yellowish protein and lipid deposits between the retinal pigment epithelium and Bruch’s membrane; large or frequent drusen can indicate early macular degeneration
hat structural changes are seen in both types of age-related macular degeneration?
- Atrophy of the retinal pigment epithelium
- Degeneration of photoreceptors
What occurs in wet (neovascular) age-related macular degeneration?
New blood vessels grow from the choroid layer into the retina and leak fluid or blood, leading to oedema and rapid vision loss.
What chemical stimulates new blood vessel growth in wet age-related macular degeneration and is targeted by treatment?
Vascular endothelial growth factor
What are six risk factors for developing age-related macular degeneration?
- Increasing age
- Smoking
- Family history
- Cardiovascular disease
- diabetes
What are the typical symptoms of age-related macular degeneration?
- Reduced visual acuity, particularly for near field objects:
- gradual in dry ARMD, subacute in wet ARMD
- deterioration in vision at night
- Difficulty reading small text
- glare around lights
What are key signs of age-related macular degeneration seen on clinical examination?
- Amsler grid testing: straight lines seen as wavy lines
- fundoscopy: drusen, which may become confluent in late disease to form a macular scar.
- in wet ARMD well demarcated red patches may be seen which represent intra-retinal or sub-retinal fluid leakage or haemorrhage.
What investigations are done for age-related macular degeneration
- slit-lamp microscopy - detailed view of the retina and macula
- fluorescein angiography - shows oedema and neovascularisation in wet AMD
- optical coherence tomography - visualise the retina in three dimensions
How are early and intermediate-stage age-related macular degeneration managed
- observation + ophthalmology review
- RF modification: stop smoking, control HTN, zinc, Vitamin A,C and E
