Painless Loss of Vision

Objectives

Facilitate accurate diagnosis in a patient with painless loss of vision and prevent permanent visual loss

1. Provide a simple guide to recognition and initial assessment of painless loss of vision.
2. Identify red flag signs/symptoms to aid triage for transfer to onward specialty care.
3. Provide advice on immediate to short term management of patients with suspected retinal detachment, central retinal artery occlusion or central retinal vein occlusion. 

Scope

This guideline provides an overview of the pathophysiology of the main causes of painless loss of vision and guidance on assessing a patient with painless loss of vision

Risk factors and initial management are discussed for retinal detachment (RD), central retinal artery occlusion (CRAO), and central retinal vein occlusion (CRVO) including specific management of traumatic retinal detachment.

This guideline does not cover neurological causes of visual loss such as central lesions.

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

The potential consequence of permanent blindness in a patient with new visual loss is a clear indication to prioritise onward referral to specialist care, however effective initial assessment can be valuable in facilitating triage, aiding effective liaison with reach-back clinicians, and informing first aid management.

RD, CRAO, and CRVO are all important differential diagnoses in acute visual loss and a typical history associated with these causes is outlined in the below table:

It is important to note that normal fundoscopic changes cannot rule out RD or CRAO

CRAO

CRAO is analogous to a stroke and should be treated in the same way. The exception to this is that for those presenting within 6 hours ocular digital massage and urgent systemic IOP lowering may be helpful in encouraging an embolus to move further down the arteriole and reperfuse the retina - give acetazolamide 500mg orally (or IV) if available. 

Urgent transfer to an appropriate specialist unit should be your priority – retinal ganglion cell death can occur in 12-15 minutes and visual loss is often permanent. In patients with suspected amaurosis fugax where vision has returned, onward referral is still urgent as this is often a precursor to sustained visual loss with the same pathophysiology.

Retinal Detachment (RD)There are limited ‘first aid’ management options for RD and the primary management objective for a patient with suspected RD should be transfer on to an ophthalmologist – the rate of successful reattachment and visual outcomes is significantly greater if intervention is achieved prior to macula involvement. This should be the priority for any patient with suspected RD, especially those with visual acuity or visual field changes, or fundoscopic changes.

CRVOAs with any patient with visual loss, patients with suspected CRVO should also be transferred on to specialty ophthalmological care where possible. Careful review of cardiovascular risk factors is also indicated.

Trauma

Patients with a history of trauma should be managed using the ‘SHIELD AND SHIP’ protocol:

Place an eye shield or other rigid covering over the injured globe. Do not pad. Provide adequate analgesia and antiemesis. Initiate systemic antibiotic cover with fluoroquinolone as per deployed antimicrobial guidance, to ensure good ocular penetration and cover against gram negative organisms.

Where direct access to an eye surgeon is not available:

• If possible, initiate telemedicine consultation with eye surgeon as soon as possible
• Evacuate all vision-threatening injuries to see an eye surgeon within 12- 24 hours if possible.

Advanced Assessment & Management

Point of care ultrasonography

Where both equipment and expertise are available ultrasound can be used as an adjunct in the assessment of patients with suspected RD.

It is important to note that ultrasound should not be used in patients with a history of trauma, this is due to the risks posed by placing pressure on an eye with a traumatic injury. 

On ultrasound detached sections of retina appear as a hyperechoic line anterior to the choroid.

It is important to note that normal sonographic appearance does not exclude RD.