Gradual Loss of Vision Flashcards
What are typical causes of gradual loss of vision?
Cataract Macular degeneration Glaucoma simple Diabetic retinopathy Hypertension Optic atrophy
What is age related macular degeneration? Who does it occur in and how does it present?
Occurs in the elderly
Degeneration of th macula with bilateral changes.
Presents with central vision deterioration.
There is pigment, drusen and sometimes bleeding at the macula due to degeneration of retinal photoreceptors.
Over time it progresses to retinal atrophy and central retinal degeneration which causes a loss of central vision.
What are symptoms of ARMD?
Initially no deterioration in visual acuity testing but difficulty making out images due to failing contrast sensitivity
Difficulty with reading and making out faces
Difficulty with night vision and with changing light conditions
Visual fluctuation
Metamorphosia - distortion of visual images
What are risk factors for ARMD?
Increasing age Smoking CVS disease FHx Cataract surgery
What are the types of ARMD?
Dry (non-exudative) 90% of cases
Macular degeneration characterised by drusen - yellow round spots in Bruch’s membrane
Wet (exudative) 10% of cases:
Characterised by choroidal neovascularisation.
Describe wet ARMD
Pathologic choroidal neovascular membranes develop under the retina.
These can leak fluid and blood and cause a central disci form scar.
Vision deteriorates rapidly and distortion is a key feature.
Fluid exudation nad detachment of pigment is seen on ophthalmoscopy
Treatment is available
Describe dry ARMD
Slower progressive visual loss
Shows drusen and changes at the macula
No treatment
What are drusen?
Yellow areas of pigment deposition in the macular area which may become confluent in late disease to form a macular scar.
Optic nerve drusen signify optic nerve head axonal degeneration - abnormal axonal metabolism leads to intracellular mitochondrial calcification.
Optic disc edge is made irregular by the lumpy yellow matter.
What are signs of ARMD?
Distorderd line of perception on Amsler grid
Fundoscopy will show drusen in dry ARMD
In wet , well demarcated red patches may be seen representing intra-retinal or sub-retinal haemorrhage.
What investigation in ARMD?
Slit lamp microscopy to identify pigmentary exudative or haemorrhagic changes affecting the retina.
Colour fundus photography.
Fluorescein angiography if neovascular ARMD is suspected as this can guide intervention with anti-VEGF therapy.
What is treatment for ARMD?
For wet ARMD:
VEGF inhibitors (bevacizumab and ranibizumab) are used to prevent vascular endothelial growth factor from increasing vascular permeability and increasing angiogenesis.
4 weekly injection
Laser photocoagulation slows progress where there is new vessel formation however risk of acute visual loss after treatment.
Dry ARMD:
No treatment but antioxidant vitamin and mineral supplements (vitamin A, vitamin E, zinc and lutein)
Stop smoking, eat green diet
What is optic atrophy?
Pale, well demarcated disc on fundoscopy
Usually bilateral and causes a gradual loss of vision
May be from raised intraocular pressure, retinal damage or ischaemia
Acquired causes: MS Papilloedema (longtanding_ Raised IO pressure Retinal damage Ischaemia Toxins (tobacco amblyopia)
Congenital
Friedrichs ataxia
Mitochondiral disorders (Leber’s optic atrophy
Wolfram’s syndrome (DI DM OA Deafness)
In young teenagers?
Stargadt macular degenration
What is choiroiditis? Cause?
Choroid is part of uvea (iris, ciliary body and choroid).
Inflammation of choroid due to toxicoplasmosis, TB, sarcoidosis
