Main

Sir,

Blunt trauma like football injury may result in commotio retinae and traumatic macular hole.1, 2 Persistent visual impairment may occur in severe cases of commotio retinae due to damage to the photoreceptors or retinal pigment epithelia. We report the use of multifocal electroretinogram (mfERG) and optical coherence tomography (OCT) in a patient with commotio retinae and traumatic macular hole following blunt ocular injury. To our knowledge, there has been no previous report in the literature on the mfERG findings following commotio retinae.

Case report

A 24-year-old man presented with left eye visual loss after blunt injury by a football. On examination, his visual acuity was 6/6 for the right eye and hand movement for the left eye. There was 2 mm hyphema with mild vitreous haemorrhage in the left eye. Fundus examination showed a localised area of commotio retinae at the superionasal part of the macula. At 2 weeks after the injury, the hyphema and vitreous haemorrhage resolved, and his left eye visual acuity improved to 6/36. He noted a relative scotoma at the inferiotemporal visual field. Fundus examination showed an area of mild retinal pigment epithelial atrophy at the site of the commotio retinae. OCT imaging revealed a 100 μm full thickness traumatic macular hole (Figure 1a). Automated visual field testing detected a relative inferionasal scotoma. MfERG demonstrated reduction in retinal response density at the central macula with a well-demarcated area of depressed retinal response density in the superionasal part of the macula (Figure 1b).

Figure 1
figure 1

(a) Optical coherence tomography of the left eye 3 weeks after injury showing a full thickness macular hole of 100 μm in size. (b) Trace array and three-dimensional topography of the multifocal electroretinogram of the left eye showing reduced retinal response density at the central macula due to the traumatic macular hole. There was also a well-demarcated area of reduced retinal response density at the superionasal part of the macula corresponding to the area of commotio retinae.

In view of the small size of the traumatic macular hole, he was observed and surgery was not performed. At 6 weeks after the injury, the left eye visual acuity improved to 6/9. OCT demonstrated spontaneous closure of the macular hole (Figure 2a). At 18 months after the injury, his left eye vision recovered to 6/6 but he still complained of a relative scotoma at the inferiotemporal field. MfERG showed recovery of the retinal response density at the central macula due to closure of the macular hole (Figure 2b). However, the well-demarcated area of depressed retinal response in the superionasal macula persisted secondary to the damage associated with commotio retinae.

Figure 2
figure 2

(a) Optical coherence tomography of the left eye 6 weeks after injury showing spontaneous closure of the macular hole. (b) Trace array and three-dimensional topography of the multifocal electroretinogram of the left eye 18 months after the injury demonstrating recovery of the retinal response density at the central macula due to spontaenous closure of the traumatic macular hole. The well-demarcated area of reduced retinal response density at the superionasal part of the macular persisted secondary to permanent loss of photoreceptors following the blunt trauma.

Comment

Previous studies have utilised OCT imaging in documenting the natural progression and spontaneous closure of traumatic macular holes anatomically.2, 3, 4 However, the changes in retinal functions following traumatic macular hole could not be assessed using OCT. MfERG is an objective tool that has been used to evaluate retinal function in various macular disorders including idiopathic macular holes and X-linked juvenile retinoschisis.5, 6 The use of mfERG in our patient enabled us to demonstrate objectively the functional improvement after spontaneous closure of the traumatic macular hole as illustrated by the recovery of the retinal response amplitude at the central macula.

Histological study of commotio retinae in primate models has demonstrated that disruption and degeneration of photoreceptor outer segments may occur after blunt ocular injury.7 As observed in our patient, the inferiotemporal visual field defect which persisted after the injury corresponded to the area of the commotio retinae. This was confirmed objectively by the well-demarcated reduction in retinal response density in the mfERG. The mfERG findings in our patient supported the suggestion that permanent visual loss following commotio retinae may occur due to permanent loss of photoreceptors. We believe that OCT and mfERG are valuable tools for assessing the anatomical alterations and functional changes of the retina, respectively, in patients after blunt ocular trauma.