Glaucoma drainage device - Paul glaucoma implant

Case contributed by Ashesh Ishwarlal Ranchod
Diagnosis certain

Presentation

There is prior unilateral closed-angle glaucoma. MRI brain for exclusion of a pituitary adenoma.

Patient Data

Age: 50 years
Gender: Female

There is minimal asymmetry of the globes, with no overt increased axial diameter of the symptomatic right globe.

The feature of note is the distortion of the right globe on varying sequences due to the MRI-compatible glaucoma drainage device (GDD) within the superotemporal quadrant of the right orbit.

The reservoir of the device is identified as a curvilinear fluid signal-intensity device overlying the superolateral globe.

MRI brain and pituitary fossa were otherwise unremarkable with the confirmed absence of a pituitary macro and microadenoma on dynamic contrast-enhanced imaging.

(Selected images have been uploaded).

Device photographs

Photo

The specific drainage device in this patient is a Paul glaucoma implant. This valveless implant is made of medical-grade silicone. It is pliable and flexible with a delicate curvilinear end plate and central reservoir. There is an attached micro-sized tube.

Dimensions:

  • length is approximately 44.9mm

  • width is 23mm and

  • extraocular plate surface area of 342.1mm2

Disclosure: I, Ashesh Ishwarlal Ranchod, have no actual or potential ethical or financial conflict of interest in relation to the devices. This case is not intended to be a personal endorsement or recommendation of this product.

Zoomed and cropped images

mri

Zoomed images depicting the distortion of the right globe and identification of a fluid signal intensity device overlying the right superolateral globe.

Case Discussion

Orbital distortion on MRI studies may be due to intraorbital/ intraocular foreign bodies, especially metallic debris. Precautionary orbital X-rays may be taken before MRI studies to confirm the absence of metallic foreign bodies in uncertain circumstances. Alternatively, revert to CT brain/ orbital imaging if there are doubts and uncertainty.

Cosmetics (including but not limited to mascara and eyeliner) may also be responsible for orbital distortion and artefacts in MRI studies.

The Paul glaucoma implant is a novel GDD and one of the newer valveless drainage devices. Its unique design allows easy implantation and reduces the risk of the known post-implantation complications of hypotony, strabismus and diplopia.

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