Staining of vitreous by indocyanine green dye post aqueous angiography

Description

A male patient in his mid-60s diagnosed with moderate primary open-angle glaucoma in both eyes and an immature senile cataract underwent left eye aqueous angiography using indocyanine green (ICG) dye (0.5%).¹ The commercially available ICG dye was reconstituted with the solvent (available with the dye) to a concentration of 0.5%. The reconstituted ICG dye was loaded in a 1 mL syringe and injected into the anterior chamber (0.1 mL) using a 30-gauge needle. Images were captured using a 30° lens (18–23 dioptre focus) on ICG angiography mode using the machine, Spectralis HRA+OCT FLEX module (Heidelberg Engineering, Heidelberg, Germany). Increased angiographic signals were noted in the nasal quadrant 60s after the injection of the dye. Consequently, the nasal quadrant was identified as the high-flow region. Visco-Bent ab interno needle gonioectomy (Visco-BANG) was performed in the high-flow nasal region.² Swan Jacob goniolens was used to visualise the nasal angle after positioning the head of the patient away from the surgeon and tilting the microscope to approximately 30° towards the surgeon. A 30-gauge needle which was bent at the proximal end of the bevel and attached to a syringe filled with 1% sodium hyaluronate was used to dilate the Schlemm’s canal followed by 30° excision of the trabecular meshwork. This was followed by standard steps of phacoemulsification. During phacoemulsification, the surgeon noted the anterior capsular striae with increased lens movement, indicating a zonular weakness. After emulsification of the nucleus, a green hue was noticed from the posterior segment (figure 1A), and intraoperative indirect ophthalmoscopy revealed vitreous staining due to ICG dye (0.5%). The posterior chamber intraocular lens was implanted, and surgery was completed as per the routine protocol with injection of air in the anterior chamber at the end of phacoemulsification. Air was injected at the end of the surgery to provide tamponade and prevent hyphema after the Visco-BANG procedure. On the first postoperative day, the patient could perceive hand movements close to his face and on examination, the fundus was not visible due to the presence of an air bubble in the anterior chamber (figure 1B). After 1 week, the visual acuity was 2/60 on the Snellen chart and slit lamp examination of the anterior vitreous along with Optos (Optos Daytona, Optos PLC, Dunfermline, UK) imaging of the fundus revealed green staining of the vitreous (figure 1C,D). The patient was kept under observation, and surgical intervention was withheld. Over 4 weeks, vitreous staining decreased and the visual acuity improved to 6/6 on the Snellen chart. Slit lamp examination of the anterior vitreous and Optos fundus image after 4 weeks documented resolved vitreous staining (figure 1E,F).

Figure 1.

Staining of vitreous by indocyanine green dye post aqueous angiography. (A) Arrow pointing at the intraoperative green hue seen from the posterior segment after emulsification of the nucleus. (B) Non-visualisation of fundus on postoperative day 1, due to air bubble in the anterior chamber. (C) Slit lamp image on postoperative week 1, with an arrow pointing at the indocyanine green dye stained (green hue) anterior vitreous. (D) Fundus image on postoperative week 1, showing indocyanine green dye stained (green hue) posterior vitreous. (E) Slit lamp image on postoperative week 4, with an arrow pointing at resolved green staining of the anterior vitreous. (F) Fundus image on postoperative week 4, showing resolved green staining of posterior vitreous.

Previous studies on aqueous angiography-guided minimally invasive glaucoma surgeries have not documented this complication of vitreous staining with ICG dye.^{1 3 4} This is the first case in the literature reporting this complication and its management. We hypothesise that zonular weakness in this patient may have led to the passage of dye from anterior to posterior segment, causing vitreous staining. Hence, all patients planned for aqueous angiography must be evaluated preoperatively for zonular weakness, and the procedure should be deferred in such cases. Another option is to use a lower concentration of the ICG dye (0.1%) with a slower injection speed. It is important for ophthalmologists to know about this complication and counsel patients regarding this, as it leads to the loss of best-corrected visual acuity in the early postoperative period. No surgical intervention is required as there is a spontaneous resolution over 2–4 weeks.

Patient’s perspective.

After the surgery I could not see properly and my vision was blurry. Slowly, with time my vision improved.

Learning points.

• With the use of 0.5% indocyanine green dye for aqueous angiography, we found vitreous staining.

• This was reversible after 4 weeks of surgery without the need for surgical intervention.

• We hypothesise that zonular weakness may have led to the passage of dye from anterior to posterior segment causing vitreous staining.

Ethics statements

Patient consent for publication

Consent obtained directly from patient(s).