Accidental Nd:YAG Laser–Induced Macular Hole in a Pediatric Patient

Introduction

Accidental laser-induced macular injuries are rare, with approximately 100 cases reported in the literature.¹ A subset of these patients, after exposure to an Nd:YAG laser, developed full-thickness macular holes.^2–12 Affected individuals were typically industrial workers, scientists, or military personnel who were exposed to the laser while not wearing appropriate protective eyewear.

Herein, we report a unique case of a young child who developed a large full-thickness macular hole after exposure to the beam of an Nd:YAG laser while playing in his grandfather’s physics laboratory. Six months after the injury, the patient underwent successful closure of the macular hole, with excellent recovery of visual acuity.

Case Report

An 11-year-old boy noticed the sudden, painless onset of blurry vision and a central dark black spot while surreptitiously playing in his grandfather’s physics laboratory. The grandfather was concurrently using a Q-switched Nd:YAG laser operating at 1,064 nm, delivering a maximum energy of 50 mJ in 8 nanosecond intervals. The patient did not initially disclose this exposure out of fear of retribution. When his symptoms did not improve 3 months later, however, he divulged his visual deficit to his parents, who immediately sought an ophthalmologic examination. The boy ultimately admitted to looking directly at the focusing beam of the laser while in the laboratory.

On examination, best corrected visual acuity (BCVA) was 20/100 in the right eye and 20/20 in the left eye. Anterior segment examination of the right eye was unremarkable, with no evidence of focal cataract or inflammation. The posterior segment (Figure 1A) was notable for clear media, a full-thickness macular hole in the fovea with focal yellow pigmentation centrally, and normal peripheral retina. Ocular examination of the left eye was unremarkable. Spectral-domain optical coherence tomography showed a full-thickness retinal defect with intraretinal cystic spaces at the edges of the hole (Figure 1B). At the base, the macular hole measured 1,077 μm.

Figure 1. (A) Fundus photograph of the right eye 3 months after initial laser exposure demonstrating a full-thickness macular hole. (B) Spectral-domain OCT of the right eye with cross-section through the fovea demonstrating a full-thickness macular hole and adjacent intraretinal cystic changes.

After fully discussing the risks and benefits of macular surgery versus continued observation, the patient’s family initially decided to defer surgical intervention. Repeat examination 2 months later revealed no change in BCVA or the size of the macular hole. The patient subsequently underwent pars plana vitrectomy with indocyanine green–assisted internal limiting membrane (ILM) peeling, infusion of 18% C3F8 gas and postoperative prone positioning for 1 week. In this pediatric eye with a well-formed vitreous, meticulous attention was directed toward lifting the posterior hyaloid and removing the ILM to ensure complete tractional relief at the edges of the hole. Three months postoperatively, BCVA had improved to 20/25 and the macular hole had closed, but there was noted to be a focal defect in the photoreceptor IS/OS junction (Figure 2A–B). While the crystalline lens remained clear at final follow-up, it is likely that the patient will develop a premature cataract.

Figure 2. (A) Fundus photograph 6 weeks after macular hole repair surgery. (B) Spectral-domain OCT 6 weeks after surgery demonstrating macular hole closure with a small photoreceptor IS/OS defect.

Discussion

The Nd:YAG laser, operating in the infrared spectrum, produces its intended effect though photothermal and photomechanical disruption.¹ The Q-switched mode allows for a shorter delivery interval in the nanosecond range, thus potentiating the effects of the laser. When the eye is inadvertently exposed, the energy is taken up primarily by the retinal pigment epithelium (RPE), instantaneously generating a temperature rise of thousands of degrees.¹ This results in tissue ionization, plasma formation, and a centrifugally migrating acoustic shock wave causing mechanical disruption of the retina, RPE, and choriocapillaris.^1,2,11

The severity of injury and associated visual loss is contingent on the extent of energy delivered to the RPE and the location of the injury. The minimum total energy required to generate a macular hole has been reported to be between 1 and 3 mJ.^2,11 With increasing energy exposure, there may be irrevocable injury to not only the photoreceptors, but also the RPE and choriocapillaris. Allen et al, identifying impaired choroidal perfusion after laser injury via indocyanine green angiography, postulated that visual recovery may correlate with the extent of choriocapillaris damage.² In addition to the depth and extent of injury, it is not surprising that parafoveal and foveal holes present with worse BCVA than extrafoveal macular holes.^1,11

Due to the rarity of this condition, the natural history of laser-induced macular holes and the factors that contribute to spontaneous hole closure are not well understood. A review of the literature identified 15 eyes in 14 patients with full-thickness macular holes secondary to Nd:YAG laser (Table). Energy exposure varied from 2.4 to 500 mJ, and the size of the hole varied from 117 to 1,250 μm. Of the 15 eyes, 12 cases were observed with four eyes achieving spontaneous closure. Late-onset spontaneous closure was observed as late as 9 months in one case, although BCVA did not improve.³ In three cases, surgical repair was attempted at 3 weeks, 6 weeks, and 5 months after the injury.^4,8,10 While all holes were successfully closed, there was no improvement in BCVA in the case with repair attempted at 5 months.⁴

Table: Summary of Reported Full-Thickness Macular Holes Secondary to Accidental Nd:YAG Laser Exposure

In contradistinction to idiopathic macular holes, which are theorized to mechanistically develop secondary to tangential tractional forces and centrifugal migration of photoreceptors, laser-induced holes result in complete disruption and loss of the associated photoreceptors and retinal tissue.⁹ Despite this etiologic difference, surgical management techniques are largely identical, with the goals involving complete release of vitreous traction at the edges of the hole followed by gas tamponade to allow centripetal migration and closure of the hole.¹³

Due to significant visual impairment and a persistent macular hole 5 months after the initial injury in our patient, we determined that surgical intervention was warranted. Given the large size of the hole and postoperative focal deficit at the IS/OS junction, our patient was fortunate to achieve an excellent visual outcome. It is likely that the depth of injury was not severe, and adjacent photoreceptors have appropriately compensated for this focal photoreceptor deficit. A prior study of idiopathic macular holes identified similar IS/OS junction deficits with no apparent compromise of visual recovery postoperatively.¹⁴

In conclusion, this is a unique case of a full-thickness traumatic macular hole from industrial Nd:YAG laser exposure in a child who underwent successful macular hole closure with recovery of visual acuity.