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Description
Micropulse transscleral laser therapy (MP- TLT) is a new laser treatment modality for lowering intraocular pressure (IOP) in eyes with refractory glaucoma. The laser uses micropulse instead of continuous wave energy to reduce side effects caused by thermal energy. The technique has gained popularity as a non-invasive mode of glaucoma therapy especially during the COVID-19 pandemic with no major side effects being reported unlike continuous wave diode laser cyclophotocoagulation.1–3
We recently performed MP- TLT with a new-generation MP3 fibre optic probe (Iridex Cyclo G6) (figure 1A) and came across a unique complication, which has important implications for the ophthalmic surgeon community.
(A) Pre-MP-TLT eye with conjunctival epithelial hyperpigmentation without any conjunctival laceration or burn and clean MP3 fiberoptic handheld probe, (B) performing MP-TLT in a sweeping motion, (C) yellow arrow showing entrapped conjunctival lacerated and burn tissue, (D) red arrow showing conjunctival laceration and burn area (pale white circular line). MP-TLT, micropulse transscleral laser therapy.
A patient in his early 70s presented with primary angle closure glaucoma to our glaucoma clinic with IOP of 26 mm Hg on four antiglaucoma medications in his right eye with vertical cup disc ratio of 0.9. The patient had a previous failed trabeculectomy and undergone cataract surgery 6 months back. It was decided to perform MP- TLT to lower the IOP as the patient was not willing to undergo another invasive surgery.
We obtained written informed consent for MP-TLT and its related complications before surgery. After topical anaesthesia with 0.5% proparacaine, with the laser settings of, power 2500 mW, total duration 80 s, treat mode ON, we performed MP-TLT in an appropriate technique instruction according to the device company with the speed of 20 s per hemisphere per pass (surgical video 1).
While performing MP- TLT, after placing 0.5% carboxy methylcellulose gel as coupling agent over cornea and conjunctiva, a conjunctival laceration was noted on the first pass with conjunctival epithelial burn in the inferior 180° area and the conjunctiva was found to be sucked inside the probe as a novel finding (figure 1) (surgical video 1). The laser therapy was aborted after first pass and the patient prescribed antibiotic–steroid combination eye drops, with lubricants and cycloplegic.
The IOP of the patient was 20 mm Hg on first operative day and 28 mm of Hg after 2 months in post operative period. The patient was counselled and planned for glaucoma drainage device surgery.
The risk of conjunctival epithelial burn is higher in eyes with increased pigmentation and which are on long-term antiglaucoma medications. This report of conjunctival epithelial burn with MP-TLT indicates that more additional studies are required to modify the MP-TLT technique in eyes which are on long-term antiglaucoma medications. Such a complication can led to scarring of the conjunctiva and adversely impact outcome of future filtering surgery. To prevent such a complication, each quadrant should be treated separately and the tip of the probe irrigated after each pass.
Patient’s perspective
I am very thankful to my doctor, the way how he managed the complication and for controlling my glaucoma progression and giving me best surgical option as well.
Learning points
Micropulse transscleral laser therapy is a non-invasive laser treatment modality in refractive glaucoma eyes.
Complications like anterior chamber reaction, conjunctival haemorrhage are common but conjunctival laceration and burn are rarely noted.
This case report highlights a novel complication like moving of conjunctival epithelial burn tissue into the probe.
This can lead to scarring of the conjunctiva and adversely impact outcomes of future glaucoma surgery.
Ethics statements
Patient consent for publication
Footnotes
Contributors ANB was involved in data acquisition, manuscript drafting, preparation, intellectual input approval and upload of final manuscript. AW was involved in surgical assistance, data acquisition and manuscript drafting. HA was involved in data acquisition and intellectual input. TD was involved in surgical procedure, manuscript drafting, intellectual input and finalisation of the manuscript.
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.
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.
Competing interests None declared.
Provenance and peer review Not commissioned; externally peer reviewed.