Paracentral acute middle maculopathy after uneventful ocular surgery with local anaesthetic blocks

Abstract

Objective: To describe the role of local anaesthetic blocks as a potential cause of paracentral acute middle maculopathy (PAMM) after uneventful ocular surgery.

Methods: Retrospective, observational, international, multicentre case series. Nine cases of PAMM with associated visual loss following uneventful ocular surgery with local anaesthetic blocks were observed in a 9-year period (2011-2020). Demographic, ocular and systemic data, anaesthetic data and surgical details were collected. Visual acuity (VA), fundus photography, fluorescein angiography, optical coherence tomography (OCT) and optical coherence tomography angiography (OCTA) images were reviewed.

Results: All nine cases were associated with decreased VA at 24 h postoperative check (ranging from hand movement to 20/200). A hyperreflective band within the middle retinal layers was observed in the structural OCT in the acute phase, evolving to thinning and atrophy of the inner retinal layers in sequential follow-up scans performed. Fluorescein angiography showed delayed perfusion in early arterial phase with normal perfusion in late venous phases. OCTA showed decreased perfusion in the deep capillary plexus. Visual recovery was variable between cases during follow-up (ranging from count fingers to 20/20).

Conclusions: A combination of a vasoconstrictive effect of the anaesthetic agent, an intraocular pressure spike and a mechanical effect of the volume of anaesthetic injected may result in decreased retinal artery perfusion and be evidenced as PAMM in OCT scans. PAMM may present as a potential complication of local anaesthetic blocks in cases of unexpected visual loss after uneventful ocular surgery.

Fig. 1. Case 1.

Paracentral Acute Middle Maculopathy (PAMM) is seen in the OD of a 40-year-old man 24 h after uneventful pterygium surgery with sub-Tenon’s block of lignocaine 2%, presenting with central scotoma and decreased visual acuity (3/60). Colour fundus photographs of both eyes. In the OD, a subtle perifoveal yellowish halo with a very subtle thinning of the retinal vessels is seen in the macular region, whereas OS fundoscopy is unremarkable (a, b). Fundus fluorescein angiography revealed a delayed arterial filling in the macular bundle of the OD in the early arterial phase (c), with normal perfusion in the late phase (d). Spectral Domain Optical Coherence Tomography (SD-OCT) shows normal reflectivity of inner retinal layers in the OS (e). A hyperreflective band in the inner retinal layers is observed in the OD, consistent with the diagnosis of PAMM (f). Six weeks after the surgery, SD-OCT reveals thinning of the inner retinal layers, with persistence of the hyperreflective band and moderate macular atrophy in the SD-OCT retinal scan (g).

Fig. 2. Case 3.

Paracentral Acute Middle Maculopathy (PAMM) associated to Central Retinal Artery Occlusion (CRAO) in the OD of an 80-year-old woman with pre-existing cardiovascular disease after uneventful phacoemulsification. Colour fundus photographs of the OD (a) and the OS (b) of the patient 24 h after the surgery in the OD. The presence of a cherry red spot with whitening of the perifoveal region and a perfused optic disc is seen in the OD (a). Spectral domain optical coherence tomography (SD-OCT) 24 h post-surgery (c, d). A hyperreflective band is seen in the inner retinal layers of the OD (c), in contrast with the normal reflectivity observed in the OS (d). Sequential follow up SD-OCT scans were performed in the next 2–8 weeks (e: 2 weeks, g: 4 weeks, f: 6 weeks, h: 8 weeks), which showed progressive thinning of the inner retinal layers and macular atrophy 2 months after the surgery.

Fig. 3. Case 7.

Paracentral Acute Middle Maculopathy (PAMM) in the OD of an 83-year-old woman 24 h after routine phacoemulsification under peribulbar anaesthesia. Colour fundus photographs of the OD 24 h after the surgery (a). A subtle whitish perifoveal halo is seen in the OD papillomacular bundle, with spared perfusion of the cilioretinal artery. Swept source optical coherence tomography angiography (SS-OCTA, Atlantis DRI, Topcon Corp, Japan) of the deep capillary plexus of the right eye (b) and the left eye (c) 24 h post-surgery, with the corresponding segmentation slabs inferiorly. Note a marked decrease in the small vessel branching of the PAMM-affected right eye compared to the unaffected left eye. Swept source optical coherence tomography (SS-OCT, Atlantis DRI, Topcon Corp, Japan) of the OD revealing a hyperreflective band in the inner retinal layers (d) in contrast with the normal reflectivity observed in the OS (e).