Ophthalmology - Loss of Vision Flashcards
Do cataracts cause sudden or gradual loss of vision?
Gradual
What are cataracts?
The lens in the eye becomes cloudy and opaque due to denatured protein.
What is the job of the lens?
Job of lens is to focus light coming onto the eye at the retina at the back of the eye.
What % of >65s have evidence of cataracts?
75%
Describe the vision loss in cataracts
- Very slow reduction in vision
- Progressive blurring/clouding of vision
- Difficulties due to glare from bright lights (‘starbursts’) – ‘haloes’ around lights
What condition may ‘haloes’ around lights indicate?
Cataracts or glaucoma
What may patients who see ‘haloes’ around lights complain of?
May complain of difficulty driving at night
Cataracts can rarely present in children. How may they be picked up in children?
- May simply present as a squint
- May be an incidental finding of leukocoria (reflection of white light)
What is leukocoria?
Leukocoria means “white pupil’ and it refers to the reflection of white light seen upon direct illumination of the fundus through the pupil, in contrast to the usual red glow.
How can cataracts be screened for during the neonatal exam?
Can be screened for using the red reflex during neonatal examination
Risk factors for cataracts?
- Age
- Smoking
- Diabetes
- Alcohol
- Sunlight exposure
- Corticosteroid use
- Trauma
- Previous eye surgery
What is the management for cataracts?
Surgery
What does cataracts surgery involve?
- Removing the lens that has developed a cataract and replacing it with an artificial lens (pseudophakia)
- Done using US waves (phacoemulsification) → done under topical anaesthetic
What is glaucoma?
Glaucoma refers to the optic nerve damage that is caused by a significant rise in intraocular pressure. This rise in IOP is caused by a blockage in aqueous humour trying to escape the eye.
What are the 2 types of glaucoma?
- Open angle
- Closed angle
Do chronic open angle glaucoma present with sudden or gradual vision loss?
Gradual
What is chronic open angle glaucioma?
Chronic open angle glaucoma refers to optic neuropathy with death of optic nerve fibres, with or without raised IOP.
What aspect of the vision is affected in chronic open angle glaucoma?
- Affects peripheral vision first until ‘tunnel vision’ is eventually experienced
- Patient may complain of knocking into objects or having to dodge cars when crossing roads
Give some other symptoms of chronic open angle glaucoma
Gradual onset of fluctuating pain, headaches, blurred vision and halos around lights (particularly at nighttime)
What may be seen in fundoscopy in chronic open angle glaucoma?
Optic disc cupping
What is optic disc cupping?
Optic disc cupping refers to the cup appearing to become larger over time, often due to fibres in the optic nerve dying. As the structural support for the optic disc is no longer there, the cup seems larger.
Which investigation is used to measure the intraocular pressure?
Tonometry
What will be seen in a visual field assessment in glaucoma?
Peripheral vision loss
What are the 4 pharmacological agents used in chronic open angle glaucoma?
- Topical beta blocker e.g. timolol → reduce aqueous production
- Prostaglandin analogue eye drops e.g. latanoprost → increase uveoscleral outflow
- Carbonic anhydrase inhibitors (e.g. Dorzolamide) → reduce aqueous production
- Miotics (e.g. pilocarpine) → increase uveoscleral outflow
What is the function of topical beta blockers in glaucoma?
reduce aqueous production
What is the function of prostaglandin analogue eye drops in glaucoma?
Increase uveoscleral outflow
Give an example of a prostaglandin analogue eye drop
Latanoprost
Give an example of a topical beta blocker
Timolol
What is the function of carbonic anhydrase inhibitors in glaucoma?
Reduce aqueous production
What is the function of miotics in glaucoma?
Increase uveoscleral outflow
Give an example of a miotic used in glaucoma
Pilocarpine
Give an example of a carbonic anhydrase inhibitor used in glaucoma
Dorzolamide
What are the 2 main complications of glaucoma?
- Optic neuropathy
- Optic atrophy
What is optic atrophy?
Optic atrophy refers to the death of the retinal ganglion cell axons that comprise the optic nerve with the resulting picture of a pale optic nerve on fundoscopy.
How would optic atrophy present on fundoscopy?
A pale optic nerve/disc
How would optic atrophy affect vision?
irreversible loss of visual acuity
What is the most common cause of blindness in the UK?
Age related macular degeneration (ARMD)
What is ARMD?
Degeneration in the macula that causes a progressive deterioration in vision.
What is the macula?
Part of the retina at the back of the eye that is responsible for central vision, most of colour vision and the fine detail of what we see. The macula has a very high concentration of photoreceptor cells – the cells that detect light.
What are the 2 types of ARMD?
- Wet (10% cases) → worse prognosis
- Dry (90% cases)
Risk factors for ARMD?
- Age
- Smoking
- White or Chinese ethnicity
- FH
- CVS disease
Does ARMD present with a gradual or sudden loss of vision?
Gradual
Describe the vision loss in dry ARMD
- Progressive, gradual loss of central vision over years/decades
- Typically complain of difficulty reading text, recognising faces and problems with vision in dim light – reduced visual acuity
- Visual fluctuation is classic presentation – day by day vision may appear to deteriorate and improve unpredictably
What is seen in fundoscopy in dry ARMD?
Drusen
What are drusen? Are they normal?
Drusen are small, yellowish deposits of cellular debris (protein + lipids) that accumulate under the retina
- Small drusen are normal
- Larger and greater numbers of drusen can be an early sign of macular degeneration (common to both wet and dry)
Describe the vision loss in wet ARMD
- Progressive loss of central vision over months
- Visual fluctuation
- Difficulty reading text, recognising faces and seeing in dim light
What is seen in fundoscopy in wet ARMD?
- Drusen
- Macular oedema