Nd:YAG laser was developed to treat posterior capsule opacities after cataract surgery.1 Its photo-disruptive laser intervention is also used for vitreolysis in patients with vitreous floaters.2–4 Despite being a relatively noninvasive treatment for significant vitreous opacities, as compared to pars plana vitrectomy (PPV), it may induce complications associated with retinal injury and crystalline lens damage.
We here present a rare case of a patient who suffered a series of complications after Nd:YAG laser vitreolysis.
A 60-year-old female patient was referred to our clinic for visual impairment in the right eye 1 week after undergoing Q-switched Nd:YAG laser vitreolysis for symptomatic floaters in the anterior vitreous (Figure 1). According to the referring doctor, her visual acuity (VA) was 6/6 and she had no cataract before laser vitreolysis. The laser parameters were as follows: wavelength, 1,064 nm; spot size, 8 μm; pulse energy, 4 mJ; three bursts, with single pulse per burst. The patient denied any other surgery, trauma history, and other pre-existing diseases, such as refractive error, diabetes mellitus, hypertension, or infectious disease. In our clinic, her best-corrected VA (BCVA) was counting fingers at a distance of 30 centimeters in the right eye and 6/7.5 in the left eye. Slit-lamp examination revealed a punched-out lesion with spreading linear rupture of the posterior capsule as well as cataract formation in the right eye (Figure 2).
External photography in the right eye before YAG laser vitreolysis. (A) Opacities in the anterior vitreous (arrow). (B) Schematic drawing of anterior vitreous opacities (arrow) according to records from the referring doctor.
External photography and retro-illumination image of the right eye at the initial visit. (A) The punched-out cataract (arrow). (B) The tear in the posterior capsule (arrowhead) and cataract (arrow).
The patient underwent phacoemulsification for the traumatic cataract, during which the disrupted posterior capsule and a portion of lens cortex dropped into the vitreous, as anticipated. PPV was performed to remove this lens material, and an intraocular lens was implanted at the ciliary sulcus. No obvious retinal injuries, such as epiretinal membrane (ERM) or focal trauma caused by laser irradiance, were noted during surgery.
At 1 month post-procedure, the patient's VA remained 6/60 in the right eye and ERM formation was noted (Figure 3A). Optical coherence tomography (OCT)-measured central macular thickness (CMT) of the right eye was 616 µm (Figure 3C). Thus, secondary PPV with ERM peeling was performed. Post-surgery, the ERM was improved (Figure 3B). One month after secondary PPV, her BCVA could be corrected to 6/20 and the CMT was measured as 411 µm (Figure 3D).
Fundus photography and optical coherence tomography (OCT) of right eye. Fundus photography shows surface-wrinkling retinopathy (A) and OCT shows epiretinal membrane (ERM) with foveal contraction (C) after the first pars plana vitrectomy. After the secondary pars plana vitrectomy with epiretinal membrane peeling, the ERM is improved (B) and OCT shows residual foveal deformation (D)
This patient developed iatrogenic cataract after undergoing Nd:YAG laser vitreolysis for significant anterior vitreous floaters. Post-PPV ERM resulted in persistent poor vision and additional pars plana vitrectomy was required for ERM removal.
The Nd:YAG laser permits noninvasive incision of transparent intraocular structures. The Q-switched Nd:YAG system produces 2- to 30-nanosecond laser pulses, which disrupt intraocular tissues by creating plasma shockwaves.2 This can cause injury to adjacent structures, such as the lens or retina, making it a potentially risky procedure.5
The efficacy and safety of using an Nd:YAG laser to treat vitreous opacities depends on the clinician's experience as well as other variables. The recommended distance from the focal plane of the photodisruptor beam to the adjacent tissue is at least 5 mm anterior to the retina or posterior to the crystalline lens.2 Bonner et al.6 reported that a YAG laser with 2- to 6-mJ pulse energies could lyse rabbit vitreal membranes safely when the focus area was 2 mm from the retina, but that the distance should be increased when using greater pulse energy, to prevent substantial retinal damage. Other coexisting factors, such as vitreous haze and irregular optical surfaces, could cause scattering of the laser and unnecessary retinal irradiance, increasing retinal damage.2,5 Thus, careful patient selection is needed before performing the laser vitreolysis procedure.
ERM is a disorder of the inner retinal surface, characterized by decreased visual acuity and metamorphopsia; it is common amongst older patients.7 Any process causing retinal injury may induce ERM formation.8–13 ERM may represent a reactive gliosis in response to retinal injury or a disease involving inflammatory and glial cells.14 In our case, the Nd:YAG laser vitreolysis, disrupted lens cortex, and intraocular surgery were all risk factors for ERM formation. Availability of macular OCT images acquired before and after Nd:YAG laser vitreolysis would have allowed comparison, but macular OCT was not performed by the referring doctor prior to the procedure. As VA before laser vitreolysis was 6/6, any ERM that may have been present was not visually significant.
In conclusion, Nd:YAG laser vitreolysis has the potential to cause disastrous complications, even though it could be an option for treating visually significant vitreous strands and floaters. Nevertheless, these side effects should be kept in mind, and the procedure should be performed with great caution, particularly in young and phakic patient groups.
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- Mainster MA, Sliney DH, Belcher CD 3rd, Buzney SM. Laser photodisruptors. Damage mechanisms, instrument design and safety. Ophthalmology. 1983;90(8):973–991. doi:10.1016/S0161-6420(83)80025-6 [CrossRef]
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- Fankhauser F, Kwasniewska S, van der Zypen E. Vitreolysis with the Q-switched laser. Arch Ophthalmol. 1985;103(8):1166–1171. doi:10.1001/archopht.1985.01050080078025 [CrossRef]
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- Bonner RF, Meyers SM, Gaasterland DE. Threshold for retinal damage associated with the use of high-power neodymium-YAG lasers in the vitreous. Am J Ophthalmol. 1983;96(2):153–159. doi:10.1016/S0002-9394(14)77782-7 [CrossRef]
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- Kozak I, Vaidya V, Van Natta ML, et al. The prevalence and incidence of epiretinal membranes in eyes with inactive extramacular CMV retinitis. Invest Ophthalmol Vis Sci. 2014;55(7):4304–4312. doi:10.1167/iovs.14-14479 [CrossRef]
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- Bringmann A, Wiedemann P. Involvement of Muller glial cells in epiretinal membrane formation. Graefes Arch Clin Exp Ophthalmol. 2009;247(7):865–883. doi:10.1007/s00417-009-1082-x [CrossRef]