Poppers retinopathy

Poppers retinopathy (also called poppers maculopathy) is a form of eye damage associated with the use of poppers. Although this condition is not completely understood, it is thought to be caused by hyperactivation of cones in the retina from high levels of nitric oxide released by poppers, which can cause retinal cell injury.

Some experts believe that poppers retinopathy most commonly occurs following a period of regular poppers use over months or years, in which small amounts of damage occur with each use and accumulate over time. However, cases in first-time users have also been reported, suggesting that the mechanism of injury can occur much more rapidly in some circumstances. The average age in which poppers retinopathy develops is around 40 years old, and patients with a longer history of poppers use had worse visual deficits initially, both of which support the concept of accumulation of damage over time being a significant factor.

Symptoms

Most individuals with poppers retinopathy develop a region of visual impairment in the center of their vision, usually in both eyes. A common narrative describes the onset of a bright circle in the center of their vision (clinically called a "phosphene", informally described as a green or yellow "eye of sauron") during a session of poppers use. After the session, the bright quality of the spot fades, but their vision remains abnormal in that area for days to weeks. The degree of impairment reported varies, from mildly reduced visual acuity and blurry vision to near-complete vision loss.

In some cases, there is clear evidence of retinal damage on a basic fundoscopic exam (taking high-resolution pictures of the surface of the retina). However, in others, a fundoscopic exam was normal, and evidence of damage could only be identified using a more sophisticated test called spectral domain optical coherence tomography (OCT).

Prognosis

With complete cessation of poppers use, most patients report substantial improvement or full recovery of their vision over a period of several months.

Prevalence

Although the number of case reports in the medical literature is relatively small (~100), it is believed that the number of affected individuals is likely much higher. Many anecdotal reports can be found online from users on social media and message boards. Additionally, some people describe commonly developing a very similar bright spot in their vision during poppers use that completely resolves 5-15 minutes after the end of a scene. It is unknown if the transient phosphene seen during use is associated with the development of mild injury that could increase the risk of more substantial vision impairment in the future, or if some users are less prone to chronic injury.

Chemical variants

While any alkyl nitrite can likely lead to the development of poppers retinopathy, there is fairly strong evidence to suggest that isopropyl nitrite in particular may have elevated risk of causing this condition. One reason supporting this view is purely empirical. Reports of vision impairment from poppers use were extremely rare prior to 2007. This coincided with the EU ban of isobutyl nitrite due to being classified as a carcinogen, and many poppers formulations transitioned to use isopropyl nitrite. In the following years, the number of case reports of poppers retinopathy greatly increased, and in cases that tested the specific formulation used by the patient, isopropyl nitrite was identified in the vast majority of these reports.

However, case reports implicating both amyl nitrite and isobutyl nitrite as causing vision loss exist, and anecdotal reports of isobutyl nitrite producing a similar phosphene during use are common online. One possible explanation for why isopropyl nitrite may be especially hazardous to cause this condition is that is it considerably more volatile than either amyl or butyl nitrites, which would allow much higher doses to be inhaled in a short period of time and cause much higher transient partial pressures in the blood with each hit. If there is a dose-dependence to this toxic mechanism, it could explain why so many more case reports are associated with isopropyl nitrite specifically, and especially why damage from a single use is now being reported.