Secondary open-angle glaucoma following YAG-laser vitreolysis
- 1 Ophthalmology, Amsterdam UMC Locatie AMC, Amsterdam, The Netherlands
- 2 Floater laser Clinic, OMC Amstelland, Diemen, The Netherlands
- Correspondence to Dr Ewout de Vries; ewoutwilcodevries@hotmail.com
Abstract
We report a case of a man in his 50s who developed open-angle glaucoma following neodymium-doped yttrium aluminium garnet (YAG) laser vitreolysis. Despite attempts to control the pressure with topical medication and selective laser trabeculoplasty (SLT), surgical intervention using a Baerveldt glaucoma valve (BGV) was needed after which the intraocular pressure was controlled successfully. This rare but serious complication highlights the fact that in certain cases long-term monitoring of intraocular pressure is necessary following laser vitreolysis.
Background
Yttrium aluminium garnet (YAG) vitreolysis is one of two possible treatment modalities for vitreous floaters, the other being definitive removal of the vitreous via pars plana vitrectomy (PPV).1 Laser vitreolysis seems to be generally well tolerated2 yet there have been reports of complications such as cataract formation, posterior capsule rupture, retinal detachment and elevated intraocular pressure.3 We would like to present an unusual complication of difficult to treat open angle glaucoma following laser vitreolysis as well as the management thereof.
Case presentation
A man in his 50s was referred to our hospital from an ophthalmology clinic specialising in laser vitreolysis. Initially, the patient suffered from a prominent floater, morphologically resembling a bottlebrush, which gave debilitating entoptic symptoms (video 1). There was no posterior vitreous detachment present and the eye was treated with two sessions of YAG laser vitreolysis. During the first treatment, the patient received 753 pulses of 1.6 mJ of energy, administered in bursts of 3–5 pulses. The second treatment followed 10 days later, where he received 515 pulses of 1.9 mJ of energy per pulse, again in bursts of 3–5 pulses.
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Differential diagnosis
Our initial differential diagnosis included primary glaucoma and other causes of secondary glaucoma besides vitreolysis-induced glaucoma. The patient history, however, was negative for alternative risk factors and there were no signs to suggest glaucoma of a secondary nature such as pseudoexfoliation material, ocular inflammation or pigment depositions on the corneal endothelium. Primary open-angle glaucoma was unlikely because the high ocular pressure was strictly unilateral and there was a strong chronological relationship between the treatment with the YAG laser and the start of increased ocular pressure. To date, there have been no signs of glaucoma in the fellow untreated eye suggesting a strong causal relationship between the vitreolysis and subsequent glaucoma.
Treatment
To control the ocular pressure, the patient underwent a Baerveldt glaucoma implant. Unfortunately, 1 day after the operation the ocular pressure was measured to be 50 mm Hg due to postoperative hyphema and obstruction of the tube due to bloodcoagulation. Aqueous paracentesis was attempted several times; however, refractory increases in ocular pressure ensued. Surgical revision of the Baerveldt and washout of the blood obstructing the drainage tube was performed and the ocular pressure stabilised around 15 mm Hg with adjunctive use of dorzolamide two times per day, timolol two times per day, and bimatoprost four times a day.
Outcome and follow-up
Unfortunately, the complications associated with the Baerveldt procedure caused further glaucomatous damage and increased cupping of the optic disc, thinning of the retinal nerve fibre layer and increased corresponding visual field defect were seen. During the 6 month follow-up period, following the revision of the Baerveldt, the ocular pressure remained between 14 and 15 mm Hg and the glaucomatous damage remained stable. The target pressure was set at ≤15 mm Hg and the patient returned to a peripheral ophthalmology clinic for further controls.
Discussion
Entoptic phenomena associated with vitreous floaters have been shown to be distressing and have a large negative impact on health-related quality of life in a subset of individuals.4 5 YAG laser vitreolysis offers a relatively inexpensive and non-invasive therapeutic option for the treatment of floaters when compared with pars plana vitrectomy. Still, large-scale studies investigating the efficacy and safety profile of laser vitreolysis are lacking.
To the best of our knowledge, this is the second report detailing secondary open-angle glaucoma following YAG laser vitreolysis, following a case series of three eyes by Cowan et al.6 The patients in the report by Cowan et al were treated primarily with SLT and trabeculectomy. We opted for a Baerveldt implant because of the advanced stage of the disease and the secondary nature of the glaucoma.
Earlier reported complications following YAG laser vitreolysis include cataract formation, retinal detachment and temporary high ocular pressure.7 Still, Brasse et al concluded that the risk of serious complications such as retinal detachment and cataract formation development appear to be much lower when compared with conventional methods such as pars plana vitrectomy.8 Retrospective cohort studies seem to suggest a favourable safety profile of YAG laser vitreolysis9 10; however, randomised controlled trials (RCTs) are needed to make more definitive statements regarding treatment safety.
To date, there has been only one RCT, published by Shah et al, in which 36 eyes with Weiss-ring floaters were treated with YAG vitreolysis, and the control group of patients received a sham treatment.2 In this study, no serious complications were reported. A follow-up study was published recently in which the same patients were examined at an average of 2.3 years following treatment.11 In this study, 3 eyes were seen to develop retinal tears not described earlier; however, there were no incidences of increased ocular pressure. This suggests that the phenomenon of chronic increased ocular pressure, and as a consequence glaucoma, may be relatively uncommon.
The risk of developing high ocular pressures may be related to the type of floater being treated. In the study by Shah et al only Weiss-ring floaters were treated, while the present case followed the treatment of a bottlebrush floater, a vitreous opacity characterised visually as diffuse brush-like strands attached to a cylindrical stem. The biochemical makeup of these floaters may be such that dispersion via YAG laser releases a large amount of protein particles which may impede the proper functioning of the trabecular meshwork. Additionally, bottlebrush floaters tend to be large in size, and necessitate higher cumulative amounts of energy until the floater is rendered optically inactive. The higher energy use may present an increased risk of developing glaucoma following vitreolysis.
This report adds to the evidence that in select cases YAG laser vitreolysis can lead to the development of chronic increased ocular pressure. Patients should be fully informed of this risk before undergoing treatment to ensure shared decision making. Seeing as there is a paucity of RCTs and long-term follow-up data available to completely elucidate treatment safety, we recommend regular ophthalmological controls, including measurements of ocular pressure, following YAG laser vitreolysis, especially if the decision is made to treat floaters other than Weiss ring type floaters.
Learning points
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Yttrium aluminium garnet laser vitreolysis can potentially cause serious secondary open-angle glaucoma in select cases.
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We encourage monitoring of ocular pressure postintervention to allow for prompt treatment should increased ocular pressure occur.
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Topical treatment or selective laser trabeculoplasty may not be sufficient to control ocular pressure, in which case operative measures may be necessary.
Ethics statements
Patient consent for publication
Footnotes
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Contributors Dr EdV has collected data and written the article. Mr CF has helped with figures and writing the article. Dr FG has helped with data collection and writing the article. Dr CH has helped with writing and reviewing the article.
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Funding The authors have not declared a specific grant for this research from any funding agency in the public, commercial or not-for-profit sectors.
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Case reports provide a valuable learning resource for the scientific community and can indicate areas of interest for future research. They should not be used in isolation to guide treatment choices or public health policy.
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Competing interests None declared.
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Provenance and peer review Not commissioned; externally peer reviewed.
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References
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