Using selective laser trabeculoplasty to manage glaucoma in a child with phakomatosis pigmentovascularis

Abstract

Purpose

To describe the management and complications associated with using selective laser trabeculoplasty (SLT) to treat elevated intraocular pressure (IOP) in a child with phakomatosis pigmentovascularis (PPV).

Observations

A 13-year-old female with bilateral cutaneous hemangiomas of the face and lower limb length discrepancy presented with elevated IOP in the right eye despite maximal medical glaucoma management. There was no evidence of buphthalmos, Haab's striae, posterior embryotoxon, or anterior segment dysgenesis. Initial nerve fiber layer and visual field testing confirmed structural and functional damage, respectively. Genetic testing confirmed a variant in the guanine nucleotide-binding protein G(q) subunit alpha (GNAQ) gene, confirming a diagnosis of PPV. The right eye pre-treatment IOP was 33 mmHg and the patient was treated with 360-degree SLT. Two days later, she developed a shallow peripheral choroidal effusion in the right eye that resolved with medical management. Three months after SLT, the right eye IOP was successfully reduced to 19 mmHg after the discontinuation of acetazolamide. She maintained an IOP of 18 mmHg in the right eye 11 months after SLT on latanoprost and dorzolamide-timolol only.

Conclusions and importance

Glaucoma filtering procedures in cases of PPV pose a high risk of complications and SLT offers a less-invasive, potentially clinic-based alternative. While the patient did develop a choroidal effusion post-SLT, suspected to be secondary to decreased IOP, this resolved with medical management alone without the need for incisional surgery thus illustrating both the risks and benefits of SLT in treating patients with phakomatoses-associated glaucoma.

1. Introduction

Phakomatosis pigmentovascularis (PPV), Sturge Weber (SWS), and Klippel Trenaunay Syndrome (KTS) share overlapping clinical characteristics as phakomatoses associated with glaucoma. Because all three conditions are rare, there is limited literature discussing the surgical approach to managing glaucoma in these children who progress despite medical management. Glaucoma filtering procedures and incisional angle surgery in these conditions pose a high risk of complications such as choroidal hemorrhage, detachment, or effusion.1, 2, 3 We describe a 13-year-old child with PPV and unilateral elevated intraocular pressure (IOP) successfully treated with selective laser trabeculoplasty (SLT), a less invasive, potentially clinic-based procedure. We also describe a rare complication where the child developed a post-SLT choroidal effusion with subretinal fluid that resolved after one month of medical management.

2. Case presentation

A 13-year-old female was referred to the pediatric glaucoma service at Children's Hospital of Philadelphia due to uncontrolled IOP in the right eye. Upon review of her outside records, at ten years of age during a routine eye exam with optometry, she had a normal eye exam. Subsequently she presented for a failed vision screen at age 12 years and was found to have an untreated IOP of 41 mmHg with advanced cupping of the right optic nerve. Given her normal eye exam a few years prior, she was unlikely to have had early-onset congenital glaucoma. She had an unremarkable birth history and was born full term. There was no notable family history of glaucoma. Best corrected visual acuity measured by Snellen was 20/40 in the right eye and 20/20 in the left eye. The patient was using maximum medical therapy only in the right eye including latanoprost at bedtime, dorzolamide-timolol two times a day, brimonidine three times a day, netarsudil once daily, and oral acetazolamide 375 miligrams two times per day (10 miligrams/kilogram/day) with an IOP measured by applanation of 23 mmHg in the right eye and 21 mmHg in the left eye. Gonioscopy demonstrated an open angle with visible scleral spur 360° without increased angle pigmentation in both eyes. Anterior segment examination revealed bilateral eyelid and scleral discoloration consistent with oculodermal melanocytosis. There was no evidence of buphthalmos, Haab's striae, posterior embryotoxon, or anterior segment dysgenesis. Dilated fundus examination demonstrated a cup-to-disc ratio of 0.95 in the right eye without significant cupping in the left eye (Fig. 1a). The macula, vessels and retinal periphery were normal in both eyes without evidence of choroidal hemangioma.

Fig. 1.

A 13-year-old female with phakomatosis pigmentovascularis was referred for management of elevated intraocular pressure with advanced glaucoma in the right eye (OD). a. Optic disc photographs at initial presentation demonstrating significant cupping of the optic nerve OD (left image) without significant cupping of the optic nerve of the left eye (OS) (right image). Baseline Glaucoma Testing. b. Baseline optical coherence tomography of the retinal nerve fiber layer (OCT RNFL) demonstrating thinning in all quadrants of the right optic nerve, with a normal RNFL of the left optic nerve. c. Baseline Humphrey Visual Field (HVF) 24-2 demonstrating a dense inferior arcuate defect with a nasal step and early superior arcuate defect within 5 degrees of central fixation OD, while it was within normal limits OS.

Initial glaucoma testing included optical coherence tomography of the retinal nerve fiber layer (OCT RNFL) using the Heidelberg Spectralis which demonstrated significant thinning in all quadrants of the right eye (Fig. 1b). Humphrey Visual Field (HVF) 24-2 testing showed a dense inferior arcuate defect with a nasal step and an early superior arcuate defect within 5 degrees of central fixation in the right eye (Fig. 1c). OCT RNFL and HVF in the left eye were normal.

External exam demonstrated bilateral cutaneous hemangiomas of the face distributed in the V1 and V2 dermatomes with lower limb length discrepancy and varicosities. SWS, KTS, and PPV were considered. Genetic analysis was performed by the Perelman School of Medicine at the University of Pennsylvania Genetic Diagnostic Laboratory using the University of Pennsylvania Somatic Overgrowth Vascular Malformation panels (Clinical Laboratory Improvement Amendments identification number: 39D0893887). The panels used next generation sequencing to assess 34 genes, with a skin and lip biopsy confirming a variant in the guanine nucleotide-binding protein G(q) subunit alpha (GNAQ) gene, without abnormalities in phosphatidylinositol-4,5-bisphosphate 3-kinase catalytic subunit alpha (PIK3CA), as was additionally confirmed by Sanger sequencing. In conjunction with the clinical findings, a diagnosis of PPV was made. The patient was heterozygous for a single base substitution, c.548G > A, in exon 4 of the coding sequence of the GNAQ gene. This variant is classified as “pathogenic” according to the lab's variant classification system, which is based on the American College of Medical Genetics and Genomics guidelines.⁴ PPV is strongly associated with postzygotic somatic mosaic variants in GNAQ and the c.548G > A variant is a somatic variant which can be detected at low levels in affected tissues but may be undetectable in blood samples.^5,6

After careful discussion with the parents who preferred to avoid incisional glaucoma surgery, SLT was offered as a less-invasive procedure. After a discussion of the risks and benefits including the limited evidence for the use of SLT for glaucoma in PPV, SWS, and KTS, the parents elected to proceed. No adjustments were made to her medications. The patient had no developmental concerns that were perceived to limit her ability to tolerate an in-clinic procedure. The goal of therapy was to achieve an IOP of less than or equal to 21 mmHg while reducing her medication burden. While an IOP goal of less than or equal to 21 mmHg is not a universal standard in managing pediatric glaucoma, in this patient's specific situation, the initial IOP in the unaffected healthy left eye was 21 mmHg and thus the target was set to achieve a close to symmetric IOP between both eyes. The patient returned one week later to undergo SLT in the right eye. The pre-laser IOP was higher at 33 mmHg on maximal medical glaucoma therapy. The patient was treated with 360-degree SLT in clinic using a power of 0.5 mJ and 76 total shots (total power 38 mJ). Thirty minutes later, the patient's post-SLT IOP was 30 mmHg. Since there is no standard of care that requires additional postoperative drops after SLT, the child was not prescribed any additional medications and was advised to continue all prior glaucoma medications including oral acetazolamide.

Two days following SLT, she presented due to subjectively decreased vision in the right eye. On examination, her best corrected visual acuity by Snellen was 20/200 and IOP was 24 mmHg in the right eye. Anterior segment examination was stable, while posterior examination demonstrated subretinal fluid in the macula with a shallow peripheral choroidal effusion in the right eye (Fig. 2a). This was hypothesized to be due to the reduction in IOP following SLT. Acetazolamide and netarsudil were discontinued. Atropine 1% and prednisolone acetate 1% eye drops were initiated twice a day in the right eye and one day after adjusting the treatment (or three days post-SLT), her IOP was 18 and 15 in the right and left eyes, respectively. The additional drops were continued for one month, resulting in resolution of the subretinal fluid (Fig. 2b). Three months post-SLT, visual acuity returned to baseline and IOP in the right eye was 19 mmHg on dorzolamide-timolol, brimonidine, and latanoprost eye drops and 19 mmHg in the left eye. At the 11-month post-procedure visit, her vision was stable and IOP was 18 mmHg in the right eye only on latanoprost and dorzolamide-timolol after the family had self-discontinued brimonidine. The IOP in the left eye was 18 mmHg without the use of any glaucoma medications. There was no macular edema on follow up OCT of the right eye. Repeat visual field testing was stable in both eyes.

Fig. 2.

A 13-year-old female with phakomatosis pigmentovascularis underwent selective laser trabeculoplasty (SLT) in the right eye to treat her elevated intraocular pressure which resulted in a choroidal effusion. Optical coherence tomography (OCT) Macula of the right eye. a, Two days following SLT, she developed subretinal fluid in the macula (star); b, One month after discontinuing acetazolamide and netarsudil and initiating topical prednisolone acetate and atropine, there was resolution of the subretinal fluid.

3. Discussion

After accessing PubMed on April 19, 2025 utilizing the key words "Selective Laser Trabeculoplasty" and "Phakomatosis Pigmentovascularis", we did not find any prior cases that reported using SLT to treat glaucoma associated with PPV. While more literature exists on managing glaucoma in SWS, less is known regarding how to manage glaucoma in PPV or KTS. These three phakomatoses have been suggested to present as a spectrum of disease with PPV being reported most frequently as overlapping with SWS or KTS.¹ To further support the suggestion that these entities lie on a spectrum of disease, all three are proposed to be disorders of neural crest migration resulting in developmental anomalies of the angle.⁷ Among these diseases, PPV is especially rare, with an estimated 300 cases reported worldwide as of 2022.⁸

Filtering surgery in this subgroup of vascular malformations is associated with significant risk for expulsive choroidal hemorrhage, detachment, or effusion due to a sudden decrease in IOP in the setting of venous dysplasia contributing to choroidal thickening and increased vascular permeability.1, 2, 3

Glaucoma drainage devices have demonstrated variable risk and benefit profiles,³ with one study reporting a statistically significant reduction in IOP and medication burden in SWS children who received Ahmed implants, reporting a cumulative probability of success rate of 75% (defined as achieving the IOP target without additional surgery or escalation of medical treatment) with a mean follow-up of 2.1 years; only 12.5% developed a postoperative choroidal detachment.⁹ Another study examining Molteno implants in children with SWS reported limited long-term success rates with significant complications where 33.3% developed choroidal effusions necessitating drainage; at postoperative month six, zero eyes achieved absolute success (defined as reaching the IOP target without glaucoma medications), and with a mean follow-up of 2.7 years, the cumulative probability of relative success (defined as achieving the IOP target) at the final follow-up visit was 43.34%.¹⁰

Angle surgery such as Ab externo microcatheter-assisted trabeculotomy has demonstrated efficacy in treating glaucoma from SWS, though surgical success rates were lower in PPV.¹¹ Combined trabeculotomy-trabeculectomy has also been reported as a safe, effective procedure to manage glaucoma in PPV, though it is not widely used.¹²

Reports using laser therapy in these vascular malformations is limited. Only one study included the use of transscleral cyclophotocoagulation in patients with PPV with poor visual potential, though individual outcomes for these patients were not reported.¹² Argon laser trabeculoplasty reduced IOP in SWS in two cases,¹³ but SLT has not been studied in glaucoma associated with PPV, SWS or KTS. SLT, through an unknown mechanism, is the only treatment that increases outflow through the trabecular meshwork (TM).^14,15 Thus, SLT offers an alternative to glaucoma medications that decrease aqueous humor production and is a less invasive alternative to filtering surgeries that bypass conventional outflow.

Glaucoma in patients with PPV has been hypothesized to be due to either vascular malformations leading to abnormal angle development or due to melanocytosis of the TM.³ Our patient's angle was open on gonioscopy, and there was no apparent increased pigmentation out of proportion to normal, though she did have scleral and eyelid discoloration suggestive of oculodermal melanocytosis, which may have led to subtle angle pigmentation that was not obviously appreciated on gonioscopy. While the influence of angle pigmentation on SLT efficacy is controversial, some studies have demonstrated that a higher degree of angle pigmentation correlates with increased SLT success.¹⁴ Since SLT targets pigmented cells in the TM and patients with oculodermal melanocytosis have been shown to have hyperpigmentation of the angle,² this may have additionally contributed to the successful lowering of IOP following SLT in our patient. We consider SLT to have been a success given it allowed the patient to maintain an IOP less than or equal to 21 mmHg while reducing her medication burden with the discontinuation of acetazolamide, brimonidine, and netarsudil. While this patient had advanced cupping, in patients with vascular malformations, the authors are cautious in targeting IOP levels that may be too low as well given the aforementioned risk for developing choroidals at low pressures. Patients with advanced cupping and severely compromised retinal ganglion cells may be at higher risk for permanent vision loss from a rare but reported phenomenon of optic nerve “snuff-out,” arising after glaucoma interventions that acutely lower IOP.¹⁶ It has been hypothesized that severely cupped nerves may be more sensitive to mechanisms such as ischemia-reperfusion injury and the development of acute postoperative choroidal effusions has been associated with higher incidences of this “snuff-out” phenomenon.^16,17

While the patient did develop a choroidal effusion post-SLT, this resolved without incisional surgery over one month with medical management, illustrating both the risks and benefits of SLT in treating patients with phakomatoses-associated glaucoma. This case demonstrates the use of SLT as an effective, potentially in-office method to treat glaucoma associated with PPV in a pediatric patient and emphasizes the need for careful post-procedure monitoring for the development of choroidal effusions.

CRediT authorship contribution statement

Patricia Bai: Writing – review & editing, Writing – original draft, Visualization, Project administration, Investigation, Data curation. Kiara Corcoran Ruiz: Visualization, Data curation. Catherine Wang: Visualization. Julius T. Oatts: Writing – review & editing. Javaneh Abbasian: Writing – review & editing, Supervision, Investigation, Conceptualization.

Patient consent

Consent to publish the case report was not obtained. This report does not contain any personal information that could lead to the identification of the patient.

Claim of priority statement

After accessing PubMed on April 19, 2025 utilizing the key words "selective laser trabeculoplasty" and "phakomatosis pigmentovascularis", we did not find any prior cases that reported using selective laser trabeculoplasty to treat glaucoma associated with phakomatosis pigmentovascularis.

Authorship

All authors attest that they meet the current ICMJE criteria for Authorship.

Disclosures

The authors have no conflicts of interest relevant to this article to disclose.

Funding/support

This research did not receive any specific grant from funding agencies in the public, commercial, or not-for-profit sectors.

Declaration of competing interest

The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.