Accidental macular laser burn in a 12-year-old boy complicated with choroidal neovascularization: 4-year follow-up with spectral-domain optical coherence tomography.

Abstract

Trauma resulting from laser eye injury can induce long-term complications including choroidal neovascularization (CNV) (Fujinami et al. 2010; Raoof et al. 2014; Xu et al. 2016). We present a case of laser eye injury in a young male with resultant CNV and 4-year spectral-domain optical coherence tomography (SD-OCT) follow-up. A 12-year-old boy was referred to the eye clinic after a school nurse recorded visual acuity (VA) of six of 12 (both eyes) during routine examination six weeks prior. There was no previous ocular history. Past medical history included the following: asthma, mild cerebral palsy and attention-deficit hyperactivity disorder. Regular medication consisted of a steroid inhaler and methylphenidate. On examination, he had VA of 36 early treatment diabetic retinopathy study (ETDRS) letters (6/60) right and 72 ETDRS (6/12) left. Fundoscopy, SD-OCT and fluorescein angiography showed classic CNV with ring-shaped subretinal haemorrhage and exudates in the right eye (Fig. 1). The patient was treated for the CNV with one injection of antivascular endothelial growth factor (anti-VEGF, ranibizumab). Four weeks following treatment, there was no sign of CNV activity. After 8 weeks, however, there was further haemorrhage and subretinal fluid, and a second ranibizumab injection was given. The boy had no ocular family history and denied laser exposure and sungazing. Electrooculography and electroretinography were unremarkable and the patient was referred for genetic studies, which proved negative. Further enquiry revealed that the boy's friend had purchased a green laser pointer while on holiday in Eastern Europe. The patient admitted to playing with the laser about 9 months previously, but denied looking directly into it. A diagnosis of accidental macular laser burn as a cause of the maculopathy was made. Right eye VA increased to 51 ETDRS (6/30) after the first treatment with ranibizumab and was 70 ETDRS (6/12) (right) and 73 ETDRS (6/12) (left) at 4-year follow-up, with SD-OCT showing subretinal fibrosis in the right eye with minimal subretinal fluid at the base of the lesion (Fig. 1). Spectral domain optical coherence tomography (SD-OCT) of the left eye initially showed a foveal disruption of the outer retinal layer with hyperreflectivity. Six weeks later, a cystic element appeared. At 1-year follow-up, the hyperreflectivity and the cyst had disappeared, and after 4 years, only discontinuity in the interdigitation and ellipsoid zone of the outer retina remained. Over the past 15 years, there have been an increasing number of reported cases of retinal injury from commercially available hand-held lasers (Xu et al. 2016). Complications of focal foveal lesions detected on OCT include the following: outer retinal damage with hyperpigmentation, gap lesions, pigment epithelium detachments, lamellar hole and full-thickness macular hole (Raoof et al. 2014; Bhavsar et al. 2015; Xu et al. 2016; Zhang et al. 2016). Literature search revealed only three cases of CNV in children following unilateral laser pointer-induced macular injury since 2010 (Fujinami et al. 2010; Raoof et al. 2014; Xu et al. 2016). The first case included an 11-year-old boy where no invasive treatment was given because of age and mental condition, and the CNV and VA (6/30, right) were unchanged at 3-year follow-up (Fujinami et al. 2010). In the second case of a 13-year-old boy with right eye CNV and VA of 6/36, management and outcome went unreported (Raoof et al. 2014). In the third case, a 12-year-old boy received a single intravitreal bevacizumab injection to the right eye, and at 1-year follow-up, the VA had improved from 6/21 to 6/6 (Xu et al. 2016). Lasers are classed according to potential for harm. The retina is more sensitive to shorter wavelengths, and therefore, green laser pointers cause more retinal harm than red laser pointers (Xu et al. 2016). Safety-regulated hand-held lasers have a power output of <5 milliwatts (mW). One retinal-injury-implicated green laser had an output of 42 mW (Raoof et al. 2014). Laser-induced maculopathy may resemble macular dystrophy (Zhang et al. 2016), and children may be reluctant to admit to the mechanism of injury delaying the diagnosis (Raoof et al. 2014). Development of CNV is a rare but serious complication. In our case, CNV was treated successfully with intravitreal anti-VEGF with no reactivation during 4-year follow-up. The outer retina partially recovered over the years, and the boy kept driving licence vision in both eyes, but will require lifetime ophthalmological monitoring for CNV. We wish to raise awareness of the danger of imported laser ‘toys’ of uncertain safety classification.