Painful Loss of Vision

Objectives

To outline diagnosis and treatment of painful loss of vision

Scope

Diagnosis, management and referral criteria. This guidance is pertinent to a general audience, ophthalmologists should be guided by their clinical expertise

Audience

This guideline is intended for the use of registered healthcare professionals fulfilling a role in a forward medical location or in an emergency department on deployed operations

Initial Assessment & Management

Consider likely causes:

1. Iritis/Uveitis
2. Acute Angle Closure Glaucoma
3. Endopthalmitis
4. Temporal or Giant Cell Arteritis
5. Optic neuritis
6. Preseptal and orbital cellulitis (see CGO)

Note that traumatic causes of painful loss of vision are covered in separate CGOs, including chemical, thermal and laser burns; corneal injuries and open globe injury.

Iritis/uveitis

• Light-sensitive red eye is the hallmark feature
• Conjunctival injection and or limbal flush is a key feature for diagnosing anterior uveitis. In the absence of redness, consider an alternative diagnosis.
• Irregular pupil may be present
• Affected pupil may be small and not dilate/react as fully as the unaffected eye

Negative findings:

• There should not be fluoroscein uptake in cornea
• Pain on eye movement or restriction of eye movements is not typical. Pain on eye movements is more typical of scleritis, whereas restricted movements in a painful red eye suggest orbital inflammation or injury.
• Pain should not be reduced by instillation of topical anaesthetic drops

Treat with betamethasone eye drops and/or tropicamide drops. If the iritis is secondary to infection then appropriate antimicrobials should be administered in accordance with current DMS antimicrobial policy.

Acute angle closure glaucoma

Although glaucoma is often non-traumatic in the civilian population, in the military context it is usually precipitated by blunt injury causing hyphaema (bleeding into the anterior chamber) or damage to normal pressure-controlling structures in the eye. This causes optic neuropathy due to raised intraocular pressure.

• Entire head headache centred around the eye
• Fixed, mid-dilated pupil
• Shallow anterior chamber
• Corneal oedema (hazy cornea)
• Conjunctival injection (redness)
• Sudden onset of severe pain
• Globe may feel hard to palpation through closed lids compared to contralateral eye due to increase intraocular pressure
• Severe photophobia with associated nausea/vomiting is common
• Patients may have a history of hypermetropia (longsightedness – needing glasses for close work with a ‘plus’ prescription).

Acute angle closure glaucoma requires urgent specialist input. Discuss with an opthalmologist if possible, and aim to shield and ship - protect the eye and evacuate the patient - at the earliest opportunity. In the meantime, keep the patient lying flat in the supine position if possible, and give analgesia and anti-emetics to control symptoms.

Endophthalmitis

Endophthalmitis usually occurs post-operatively or after penetrating trauma, although may occasionally be seen as a result of endogenous spread in septic/immunosupressed patients

Likely features:

• History/suspicion of penetrating eye trauma
• Significant pain/headache with photophobia and severely reduced vision
• Likely relative afferent pupillary defect (RAPD)
• Erythema
• Hypopyon visible (inflammatory exudate in the anterior chamber)

If encountered on deployed operations without a history of eye trauma, it is most likely that this has spread endogenously from a remote source: look for and treat the systemic infection; use empirical antibiotics as per current DMS antimicrobial policy if no source cannot be identified.

Optic neuritis

• Painful eye movements
• Visual loss ranging from slight blurring to complete loss of vision in the affected eye
• Reduced colour vision, especially red
• Visual field defects
• Photopsia
• Relative afferent pupillary defect
• A swollen optic nerve may be apparent on retinal examination, although retrobulbar optic neuritis is common and the nerve may appear normal.

In the deployed setting it is unlikely that the benefits of early steroid treatment outweigh the risks. Discuss with an opthalmologist as soon as possible with a view to evacuating the patient when able.

Pre-Septal or Orbital Cellulitis

Upper respiratory tract or superficial soft tissue infections may lead to cellulitis.  Orbital cellulitis is rapidly progressive and potentially both sight and life-threatening.

Priorities are to distinguish between pre-septal (involving superficial facial/lid tissue only) and orbital (involving tissue posterior to the orbital septum/inside the orbit), initiating immediate treatment and prompt evacuation if orbital cellulitis is identified. See full CGO for pre-septal or orbital cellulitis.

Advanced Assessment & Management

In general for patients with a painful loss of vision, advanced assessment and management will follow the same guidance described above, including continuing to seek urgent discussion with and/or prompt evacuation to an ophthalmologist.

Glaucoma

In addition to initial management (analgesia and anti-emetics):

• Give Acetazolamide 500mg IV initial dose (can give orally if IV not available), then 250mg PO every 4 hours to a maximum of 1g per 24 hours
• Start intra ocular pressure (IOP)-lowering topical medications if available:
  • Topical pilocarpine every 4-6 hours.
  • IV mannitol 20% 1g/kg over 45 minutes via infusion pump can be used if alternative medications above have not broken the attack. Continue to use topical medications immediately after using the mannitol as topical medication absorption will greatly increase following the temporary pressure reduction produced by the mannitol.
• If not already achieved, attempt reachback to an opthalmologist and prepare to evacuate the patient at the earliest opportunity.
• If evacuation is delayed then continue regular topical and systemic IOP-lowering medications as above, in discussion with an ophthalmologist, if possible.