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Key learning points – ophthalmology



Key questions – ocular disorders

  • Half of cases of infectious conjunctivitis will be viral and the vast majority of bacterial conjunctivitis is self-limiting.
  • A Cochrane review examined use of antibiotics versus placebo for acute bacterial conjunctivitis and found symptoms resolved more quickly with antibiotics but the benefits were marginal.
  • The typical signs of an acute conjunctivitis are grittiness, redness and discharge without visual disturbance.
  • Swabs should be taken for neonatal conjunctivitis, highly purulent, or where there is lack of response to treatment.
  • There is very little evidence from clinical trials of antibiotic against placebo for corneal abrasions.
  • Serious complications from laser refractive surgery are now extremely rare.
  • Smoking is a clear risk factor for both cardiovascular disease and age-related macular degeneration.
  • Hyperlipidaemia has been linked to age-related maculopathy
  • But a Cochrane review concluded that statins do not have a role in preventing or delaying the onset or progression of ARMD
  • Eating oily fish at least twice a week has been associated with a reduced risk of ARMD.
  • But there is insufficient evidence to recommend omega 3 fatty acid supplementation for ARMD prevention in the general population.
  • Some forms of glaucoma are both more frequent in certain ethnic groups and may take a more aggressive course.
  • Phakoemulsification is the most common cataract surgery – where an ultrasonic probe is used to break up or emulsify the cataractous lens.

Rational management of opticians’ letters

Glaucoma

  • Asymmetry in disc cupping is significant
  • The hospital standard of visual field test is the Humphrey machine.
  • Often patients are referred with one or two spots missing or an edge defect, which is often an artefact.
  • Some visual fields are definitely abnormal in appearance and compatible with a diagnosis of glaucoma

Cataract

  • Include the optician’s assessment with a cataract referral
  • Following cataract surgery some patients will develop thickening of the posterior capsule

Retinal abnormalities

  • Retinal pigmented lesions are important findings – ranging from an insignificant pigment spot to a dark, relatively large area.
  • These are usually innocent but a choroidal naevus has the potential to become malignant.
  • Ocular migraine episodes are usually typical and not necessarily accompanied by a headache.
  • Posterior vitreous detachment is extremely common and usually experienced by patients in late middle age or earlier in myopia.

Age-related macular degeneration

  • It’s important to know the type of macular change – in order to refer appropriately
  • Dry macular change can cause gradual reduction and some distortion of central vision.
  • Wet macular change is characterised by a history of sudden visual change, particularly central distortion.

Lesions of the eyelid

  • Meibomian cysts are firm, painless nodules – usually solitary although multiple cysts can be found – small lesions can be left alone
  • Hordeolum is an acute focal infection – usually staphylococcal – and are focal abscesses and present with a painful, warm, swollen, red lump on the eyelid.
  • Xanthelasma are painless, soft, yellowish lesions in the inner eyelid –and medical care involves dietary advice and lipid-lowering therapy if necessary.
  • Anterior blepharitis centres on lashes and follicles while posterior blepharitis involves the meibomian glands – patients usually experience burning, itchy, erythematous lids.
  • Entropion is an inversion of the eyelid, usually the lower. It can lead to ocular surface damage if left untreated.
  • Ectropion is an eversion of the eyelid, usually the lower -patients may complain of epiphora, recurrent infections, irritation or the sensation of a foreign body.

Ten Top Tips- managing red eye

  • Anyone presenting with a red eye needs to be examined and have visual acuity checked.
  • If anyone who wears contact lenses develops a red eye – irrespective of whether there is pain, photophobia or visual blurring – they must be referred to eye casualty immediately
  • The main causes of photophobia are corneal lesions and anterior chamber inflammation – commonly seen as iritis.
  • Viral conjunctivitis is irritating but shouldn’t be painful and doesn’t cause much visual disturbance.
  • Allergic conjunctivitis is generally seasonal but can occur with winter allergens and tends to be itchy and less red.
  • Chlamydial conjunctivitis tends to have more redness and discharge but less itch.
  • Conjunctivitis occurring five to 19 days after birth is a medical emergency and a notifiable disease.
  • Some 15% of all shingles cases affect the first division of the trigeminal nerve – herpes zoster ophthalmicus.

Ophthalmology referral dilemmas

  • The sixth and third nerve palsies are the most common in clinical practice.
  • Most obvious cases will be seen as a convergent squint when looking straight ahead (sixth nerve palsy) and a divergent squint (third nerve palsy).
  • There are two main diagnoses to tease out with transient visual loss– amaurosis fugax and ocular migraine
  • Both are neurological but routinely dealt with by ophthalmology
  • In ocular migraine there is a visual disturbance of spiralling or zigzagging lights culminating in loss of central vision and eventual recovery- the whole process takes 20-30 minutes.
  • Amaurosis fugax is a form of TIA and is a potential precursor to stroke.
  • Acutely, cases of facial palsy are best referred to ENT but ophthalmology referral is required fairly promptly if there is concern about corneal exposure.

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