49 Traumatic optic neuropathy

Background

Definition

Traumatic optic neuropathy is an injury to the optic nerve following an episode of trauma, which may be direct or indirect.1,2 Traumatic optic neuropathy is a clinical diagnosis based on reduced vision (not explicable by other ophthalmic problems), presence of a relative afferent pupil defect (RAPD),3 reduced colour vision, and an associated visual field defect.4–6 The clinical examination can be complicated by the level of the patient’s consciousness and other problems associated with the trauma.

Incidence

The incidence of traumatic optic neuropathy is estimated to be between 0·7% and 2% of all cases with head trauma,4,7,8 and the population affected is young and predominantly male. The international optic nerve trauma study showed an average age of 34 ± 18 years, of whom 85% were male.9 Similar results have been seen in other studies.10–12 These studies used patients who presented to the emergency department with head trauma who were subsequently identified to have an ophthalmic injury.

Aetiology

Motor vehicle or bicycle accidents are the most common cause of trauma.9–12 Direct optic nerve trauma results from a penetration of the orbit that involves the optic nerve, such as a stab to the orbit. These produce severe and immediate visual loss.2,13 Indirect optic nerve trauma is caused by forces transmitted from a distant injury to the optic nerve.1,14 These may be associated with visual recovery and delayed visual loss. The degree of visual loss can be severe or mild.14

Prognosis

Visual improvement in untreated cases of indirect traumatic optic neuropathy has been reported in 25% to 45% of patients.9,10,12,15 The prognosis is less good if the injury is direct and if the initial visual loss is more severe.10 This leaves a large percentage of indirect traumatic

optic neuropathy patients who make no post-trauma improvement and who have visual loss.

Treatment options

The treatment options are no treatment, medical treatment with the use of systemic steroids in high or very high doses, and surgical treatment with decompression of the optic canal.

Question

What is the best form of treatment for visual loss from indirect traumatic optic neuropathy that does not improve spontaneously?

The evidence

No randomised controlled trials were found.

Comment

Only one prospective study of indirect traumatic optic neuropathy has been performed.9 The study was a nonrandomised, non-masked comparative interventional study with concurrent treatment groups. The aim of this study was to compare corticosteroids, optic canal decompression, and no treatment. The study was performed over a three-year period on 206 patients by 76 investigators in 16 countries. The patients were treated as deemed appropriate by the individual investigators according to their customary practice. The results are summarised in Table 49.1. The results show that there is no significant difference in the improvement of vision between the three groups. The confounding features that might have influenced the results were that the surgical group included more severe cases and cases that did not respond to steroid treatment. The study was underpowered because of the relative rarity of the cases.

All other reports are those of retrospective studies,10,11,12,15 and these have not been randomised, controlled or masked studies. They all produced similar results showing no difference between the three treatment options.

Ocular oncology is a small ophthalmic sub-specialty dealing with diagnosis and treatment of patients with ocular tumours and related disorders. Such specialist services are limited to a few large ophthalmic centres that can offer multi-specialty care involving oncologists, radiation oncologists, paediatricians, paediatric oncologists and genetic counsellors. As ocular tumours are rare, only few studies involving large numbers of patients have been conducted. Nevertheless, issues in ocular oncology are

important as they not only impact visual outcome but also ocular salvage and life prognosis.

The aims of this section are to describe the available evidence from large case series, retrospective studies as well as even small case series to highlight important questions that have yet to be addressed. The section comprises three chapters delaing with common ocular tumours such as eyelid tymours, uveal melanoma and retinoblastoma.