Download Wood, C

Abstract:
A 68-year-old male presents with unilateral engorged episcleral vessels and elevated
intraocular pressure of 37 mmHg. After making a diagnosis of elevated episcleral venous
pressure, one must rule out cavernous sinus fistula.
I. Case History

67 year old white male

CC: Unilateral red eye and near blur

Hx: hyperlipidemia, hypertension, peripheral vascular disease,
coronary artery disease, polycythemia vera

Ocular hx: narrow angles with LPI OU about 10 years ago
II. Pertinent findings

Engorged episcleral vessels OS

IOP 20/37 OD/OS on initial visit

Gonioscopy: open angles with red tinge to TM OS

C/D: OD: 0.20 OS: 0.35

Pachymetry 566/590 OD/OS

FDT: repeatable superior nasal and inferior cluster OS; clean field OD

CTA did not reveal AV abnormality
III. Differential diagnosis

Carotid cavernous sinus fistula

Idiopathic increased episcleral venous pressure

Sturge-Weber
IV. Diagnosis and discussion

Carotid cavernous sinus fistula can lead to a mixing of arterial and
venous blood leading to a decrease in arterial pressure and an increase
in episcleral venous pressure on the side of the fistula. This is due to
the flow of aqueous beginning at the trabecular meshwork and
proceeding through Schlemm’s canal, the aqueous veins, the anterior
ciliary veins, the episcleral veins, and then the inferior and superior
ophthalmic veins to the cavernous sinus. Blood seen in Schlemm’s
canal while performing gonioscopy is an important clinical sign of
increased episcleral venous pressure. The IOP increases reflexly in
accordance to the Goldmann equation: IOP = (F/C) + EVP where F =
aqueous formation rate, C = aqueous outflow rate, and EVP =
episcleral venous pressure. This condition can lead to unilateral
glaucoma and often responds poorly to topical medication.
V. Treatment and Management

On initial visit, when IOP was 20/37 OD/OS, Iopidine 0.5% was
instilled OS and reduced the IOP to 35 (after dilation). Began timolol
0.5% 1 gtt BID OS.

On week follow up IOP was 20/37, added Simbrinza and referred for
possible SLT or trabeculectomy

Increased episcleral venous pressure typically responds poorly to
topical medication because these drops only reduce the gap between
IOP and episcleral venous pressure. The only medication family that
works independently of episcleral venous pressure is prostaglandins.

SLT is only mildly effective due to the outflow facility being normal.

Surgical intervention with trabeculectomy is often necessary to
stabilize patients, however, there is an increased risk of choroidal
effusion with incisional surgery due to sudden decompression if
preoperative IOP is very high.
VI. Conclusion

Management of glaucoma caused by elevated episcleral venous
pressure is challenging. Clinicians should consider elevated
episcleral venous pressure as a cause of unilateral glaucoma and
be aware of the potential treatment challenges in order to prevent
vision-threatening complications.