Poppers retinopathy

Abstract

We present a case of a 52-year-old man with sudden, bilateral central loss of vision as a result of inhalation of ‘poppers’. He was found to have characteristic changes on optical coherence tomography. With conservative treatment, the patient's vision improved marginally at 3 months follow-up. An overview of previous published cases is also included.

Background

‘Poppers’ are a group of alkyl nitrite chemicals. They cause euphoria, sexual arousal and relaxation of smooth muscles including the anal sphincter. As a result, they are particularly popular in the gay partying community. Numerous recent reports have associated the use of poppers with disruption in vision, we present such a case in a 52-year-old man.

Case presentation

A 52-year-old bisexual man presented to the ophthalmology acute referral clinic with a 10-day history of central visual blurring and metamorphopsia. He reported normal peripheral vision, and had no other visual symptoms of note. The deterioration was noted immediately following a night of clubbing, during which time the patient inhaled ‘poppers’ for the first time. He was HIV negative and systemically well.

Slit-lamp examination was unremarkable, with normal fundal views. His best corrected visual acuity was 6/15 in the left eye and 6/12 in the right, improving to 6/12 and 6/9.5, respectively, with pinhole. His pupil reactions and colour vision were normal. Spectral domain optical coherence tomography (SD-OCT) showed disruption of the inner and outer segment layers, confined to the fovea. These findings were identical in both eyes (figure 1).

Figure 1.

Spectral domain OCT on presentation, showing symmetrical disruption of the inner/outer segment layers (red arrows) top—right eye, bottom—left eye. OCT, optical coherence tomography.

The patient was treated conservatively, with advice regarding cessation of drug use. At 3 months follow-up, the patient's best corrected visual acuity improved marginally to 6/9.5 bilaterally. OCT showed improvement in the photoreceptor layer, although some mild changes in the foveal area remained (figure 2).

Figure 2.

Improvement at 3 months follow-up.

Differential diagnosis

Differential diagnoses for poppers retinopathy include photic injury, central serous retinopathy and vitreoretinal traction. Photic injury can generally be differentiated by history, while other conditions are all very unlikely to present symmetrically. This therefore highlights the importance of relevant drug history and examining both eyes.

Discussion

Alkyl nitrites, colloquially known as ‘poppers’, are recreational substances frequently used in the clubbing community due to their euphoric effects. They also cause sexual arousal and smooth muscle relaxation, being therefore especially popular among the homosexual population.¹ Poppers are not controlled under the Misuse of Drugs Act² and are therefore readily available from a variety of sources.

Despite the high prevalence of poppers, there have only been around 30 published cases of poppers retinopathy/maculopathy. The actual incidence is likely to be much higher, although the majority of these are asymptomatic.³ All cases present with bilaterally symmetrical central field loss or distortion, with preservation of peripheral fields. Other symptoms such as loss in colour vision, photopsias and positive scotomas are more variable.^4–6

SD-OCT provides the most valuable diagnostic test, showing pathognomonic disruption of the inner and outer segment layers in both foveae.^7–9 Fundus fluorescein angiograms (FFAs), when carried out, are invariable normal.

The SD-OCT findings are similar to those observed in photic injury.¹⁰ However, some recent cases have shown abnormalities in full-field electroretinography.⁵ This supports the presence of diffuse retinal damage, and is not limited to the maculae as previously thought. The current proposed mechanism of injury for poppers is that of free radical release from the nitrite chemicals.^{3 11} As a consequence, these studies advocate the use of the term ‘poppers retinopathy’ over ‘poppers maculopathy’.¹²

In poppers retinopathy, disease progression is successfully halted following abstinence from the substance in all cases. Recovery is variable, with some patients achieving complete resolution while others experience no improvement. There is no current proven therapy, however, there are reports of oral lutein therapy, which may be of benefit.⁶ The incidence of poppers retinopathy does not appear to be dose related,¹³ furthermore, there is no current evidence to suggest that patient demographics or HIV status have any influence.

At the time of writing, the ‘Psychoactive Substances Bill’ is at the report stage during its progress through the House of Commons. This new set of legislations has the intention of tightening control over substances similar to and including poppers, in the UK.

Learning points.

• Drug and sexual history can be of crucial importance in the investigation of visual disturbances.

• Poppers retinopathy presents as bilateral, symmetrical, central visual disturbances.

• Stopping the usage of poppers terminates worsening of symptoms, however, recovery is variable.