Monday, 26 June 2017

Vision Loss

Retinal Haemorrhage
This presents with sudden onset of floaters. Signs are reduced red reflex, with visible clots of blood. They must be seen by ophthalmology as retinal detachment presents very similarly, and can cause haemorrhage, and ophthalmoscopy can be normal.

There are lots of things that cause retinal haemorrhage, including:
diabetes mellitus                                      hypertension
raised intracranial pressure                      trauma and retinal detachment
retinal vein thrombosis                            subarachnoid haemorrhage
arteritis (giant cell arteritis, PAN etc.)     severe anaemia, especially pernicious anaemia
bleeding diathesis - defects in platelets (particularly leukaemia), coagulation factors, vessels.

Retinal Artery Occlusion
Sudden, painless visual loss. Central vision may be preserved if a cilioretinal artery is present. If suspected, patients should have ocular massage, and IV acetazolamide (500mg) to help. Make sure you exclude a temporal arteritis.

Central Retinal Vein Occlusion
Pizza pie on fundoscopy - flame haemorrhages with cotton wool spots. The artery has a cherry red spot with a pale macula.  Treat the cause (HT, DM,chronic glaucoma, hyperviscosity) and give antiplatelet.

IV acetazolamide 500mg IV followed by 500mg PO (1g max in 24hours), topical antihypertensives (such as timolol drops) and miotics such as pilocarpine (1 drop in the affected eye), will reduce corneal oedema and lower intraocular pressure.

Subacute attacks
Subacute attacks with blurred vision, headache and pain around the eye, nausea and vomiting, and halos seen around lights, most commonly in the evening. They resolve spontaneously.

Non-traumatic Subconjunctival Haemorrhage
Exclude systemic causes - check BP, and coag if on anticoagulants.
Reassure patients - takes 2-3 weeks to heal

You get localised conjunctival injection. It is normally benign, but may be associated with rheumatological diseases like RA, sarcoidosis, and IBD. Patients complain of irritation. It is self-limiting, but normally gets ophthalmology review to ensure it is not uveitis. The redness disappears 5 minutes after phenylephrine instillation.

Scleritis is also an inflammatory condition, frequently associated with an underlying rheumatological disorder. Patients complain of a deep dull aching pain in the eye, that is often worse at night, and ocular movement. The engorgement persists even after phenylephrine drop instillation.

The majority of cases have the HLA B27 serotype (so associated with sarcoidosis, ankylosing spondylitis, and IBD) but can also occur with herpetic keratitis, and after surgery.

Patients present with a deep, boring pain worse on accommodation. There is perilimbal injecition, and the pupil may be irregular.

Acute ischaemic optic neuropathy
Acute ischaemic optic neuropathy is most commonly caused by giant cell arteritis. Vascular wall inflammation leads to eventual occlusion, causing infarction of the optic nerve. This should be recognised, and oral prednisolone started. 1mg/kg/day for four weeks seems pragmatic. As giant cell arteritis is the most common cause, temporal artery biopsies should be performed.

A non ischaemic neuropathy usually affects young women. Pain is worse on eye movement, and visual acuity is normally reduced. There may be a central scotoma. Make sure you exclude a space occupying lesion, and refer urgently to ophthalmology.

Corneal Abrasion
Eye pads do not speed up recovery, and may worsen things.
Dilating drops are no long recommended.
Topical corticosteroids have been shown to slow corneal epithelial and stromal healing, increase the risk of infection, and cause serious scarring and visual loss if a dendritic ulcer has been missed.

Topical antibiotics may reduce the risk of infective complications in patients with a corneal abrasion. In contact lens wearers an anti-pseudomonal antibiotic must be used.

Infective Conjunctivitis 
Role of antibiotics is controversial.
Always prescribe topical antibiotics:
  Purulent / mucopurulent secretion and patient discomfort and ocular redness
  Patients and staff in nursing homes, neonatal units, critical care units etc
  Children going to nursery
  Contact lens wearers

Ultraviolet Burns

Topical and oral analgesics may be used
A mydriatic (cyclopentolate) may be helpful for photophobia due to ciliary muscle spasm

CS Spray
Dispersed as a fine dust. Irrigation can worsen the symptoms as it's highly soluble in water. Place the patient in a room, and blow a fan across, making sure no cross contamination occurs.

History and Working out what happens
- Rapid is generally vascular or retinal detachment. Slower may be a space occupying lesion.
- Partial loss of vision must be differentiated between;
    a loss of part of the visual field e.g. quadrantopia, hemianopia or central scotoma
    a curtain coming down across the vision a typical description of a retinal detachment
    flashes usually due to retinal ischaemia
    floaters due to opacities in the vitreous after retinal detachment

Local anaesthetic may be needed. Cyclopentolate takes 15-30min to work, Tropicamide - takes 15-30min to work, Tetracaine = really stings

Distance from patient to the chart / lowest line patient can be seen
Finger counting, then hand motion, then light perception

Look for aniscoria (unequal pupils) - normal in 19%. Pathologically, may occur due to release of prostaglandins on the sphincter pupillae. No reaction to light may be due to an occulomotor nerve palsy. Asides from trauma and eye drops, causes are:
Oculomotor nerve palsy (dilated pupil)
Holmes-Adie syndrome (dilated pupil)
Horners syndrome (constricted pupil)
Argyll Robertson pupil (constricted pupil)

To do fundoscopy you  may need dilating drops. Tropicamide is good - very tiny risk of precipitating acute glaucoma.

Ongoing Referral
Post op Patients:-
Less than 2 weeks post op
         Moderate or severe pain / visual loss IMMEDIATE
         Mild pain, no visual loss WITHIN 24 HOURS, in clinic if possible
More than 2 weeks post op
         Moderate or severe pain/visual loss WITHIN 24 HOURS
         Mild pain, no visual loss NEXT AVAILABLE CONSULTANT CLINIC

Flashing lights/floaters:-
Less than 6 weeks history
         Loss of vision/ field defect IMMEDIATE
         No loss of vision WITHIN 24 HOURS
More than 6 weeks history
         Loss of vision/field defect WITHIN 24 HOURS
         No loss of vision/field defect CONSULTANT CLINIC

Trauma:-(including foreign body/abrasion,chemical)
Severe pain/risk of penetrating injury IMMEDIATE
Mild pain, including suspected foreign body WITHIN 24 HOURS

Sight loss or distortion
Sudden, less than 24 hours IMMEDIATE
              More than 24hours WITHIN 24 HOURS
Gradual, less than 2 weeks WITHIN 24 HOURS
              More than 2 weeks CONSULTANT CLINIC

Assess if FB or abrasion first, if so assess for trauma
If associated visual loss use to increase priority if indicated
Severe or moderate IMMEDIATE
Associated general malaise/jaw claudication IMMEDIATE
Mild, less than 2 weeks WITHIN 24 HOURS
More than 2 weeks CONSULTANT CLINIC

Redness or swelling
Assess any associated symptoms eg pain ,photophobia, sight loss first to increase priority if necessary. Associated general malaise or pyrexia IMMEDIATE
Less than 2 weeks WITHIN 24 HOURS
More than 2 weeks CONSULTANT CLINIC

Onset less than 2 weeks, pain and/or ptosis IMMEDIATE
                                        No pain/ptosis WITHIN 24 HOURS
Onset more than 2 weeks, ptosis and pain IMMEDIATE
                                          Ptosis/no pain WITHIN 24 HOURS

                                          No pain or ptosis CONSULTANT CLINIC

No comments:

Post a comment