Patients suspected of having any one of the following immediately sight-threatening conditions should be referred urgently for a same-day assessment by an ophthalmologist.
This is a vision-threatening condition. Symptoms suggestive of angle-closure glaucoma include:
Pain in the affected eye
Halos around lights seen from one eye
Associated nausea or vomiting.
If suspected, then immediate referral for an ophthalmological opinion and treatment should be sought. Delay in the diagnosis and referral of angle-closure glaucoma has been shown to be detrimental to the final outcome. 
Immediate treatment consists of carbonic anhydrase inhibitors, such as acetazolamide or methazolamide, to decrease aqueous humour formation.
Chemical injuries, especially from alkali-based solutions, are potentially extremely serious and can lead to long-term ocular surface problems. Immediate irrigation with water or 0.9% saline solution to remove the reservoir of chemicals from the eye should be attempted before any other procedures.  The amount of irrigation required is dependent on the pH of the tear film. After the pH has normalised, referral for further ophthalmological management is advised. 
Bacterial, viral, or fungal corneal ulcers are vision-threatening conditions that need to be referred to an ophthalmologist to ensure appropriate treatment to limit corneal scarring. Corneal ulcer can lead to perforation of the eye.
This is potentially a vision-threatening condition and needs to be referred to an ophthalmologist to ensure appropriate treatment to limit corneal scarring. The patient should be advised to cease use of their contact lenses and take the contact lenses to the local eye hospital where they are seen.
Any history of a high-velocity injury (hammer usage) should be referred for appropriate and immediate imaging, as any high-velocity foreign body may penetrate the globe. This, and non-penetrating corneal foreign bodies, are potentially vision-threatening conditions and require referral to an ophthalmologist to ensure appropriate treatment.
Very gentle initial examination is required to prevent possible expulsion of intra-ocular contents. Prompt specialist treatment is required to reduce the risk of sight- and eye-threatening complications.
Scleritis is potentially a vision-threatening condition. Certain forms of scleritis can lead to perforation of the globe and reduced visual acuity.  If global perforation is suspected, the eye should be shielded and palpation should be avoided. It should be evaluated further by an ophthalmologist. Scleritis is commonly associated with connective tissue disorders including rheumatoid arthritis, granulomatosis with polyangiitis (Wegener’s), systemic lupus erythematosus, and relapsing polychondritis.
Neonatal conjunctivitis (ophthalmia neonatorum) is usually a mild illness. However, untreated infection (for example with gonococcus, chlamydia, pseudomonas, or herpes) can lead to sight-threatening complications and potentially serious systemic infection.   Complications of neonatal conjunctivitis due to chlamydia include superficial corneal vascularisation, conjunctival scarring, and pneumonia. Complications due to gonorrhoeal infections include corneal scarring, ulceration, panophthalmitis, perforation of the globe, and permanent visual impairment.    Patients with suspected neonatal conjunctivitis should be referred immediately to ophthalmology.  
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