1. Vanderbilt Eye Institute
Grand Rounds
Vanderbilt Eye Institute
12/15/06
Ryan Tarantola M.D. PGY-2

2. Initial Evaluation 10/18/06 CC: Elevated IOP OS HPI: 69 yo Female
POAG x 10 yrs
Treated with gtt and ALT OU
IOP OS has been poorly controlled
Red eyes OS>OD for many years
Referred by outside ophthalmologist for possible filtering procedure.

3. POH: POAG
S/P ALT OU
No history of trauma or steroid exposure
Allergies: NKDA
FH: No hx of eye disease

4. SH: Denies tobacco, alcohol, or drug use.
ROS: Negative
Meds: Lumigan OU QHS
Azopt OU BID

5. VAcc at Distance: OD: 20/25
OS: 20/25
Pupils: 42mm, no RAPD OU
TA: OD: 19
OS: 26
Visual Fields: FTFC OU
Motility: Full OU

8. OD

9. OS

10. Slit Lamp Exam:
External: WNL OU
Lids/Lashes: Clear OU
Conjunctiva: Engorged episcleral veins OS>OD

11. Slit Lamp Exam cont.:
Cornea: Clear OU
AC: D/Q OU
Lens: 2+ NSC OU

12. Slit Lamp Exam cont.:
Gonioscopy: Open to SS/CBB 360 degrees OU
No PAS/NV
Blood in Schlemm's canal OS
Pachymetry: OD:599
OS:600

13. Dilated Fundus Exam:
Vitreous: Clear OU
Optic Nerves: C/D: OD:0.5 OS:0.6
Small nerves OU
Thin inferiorly OS>OD
Macula: WNL OU
Periphery: WNL OU

14. Questions?

15. IOP=F/C + Pe Goldmann Equation
F=Rate of Aqueous Formation (normally 2-3 µl/min)
C=Facility of Outflow (normally 0.2 to 0.3 µl/min/mmHg)
Pe=Episcleral venous pressure (normally 8 to 10 mmHg)

16. Three Routes of Orbital Venous Drainage
1. Superior Ophthalmic Vein
Cavernous Sinus
Schlemm’s Canal
Internal Jugular Vein
Deep and Mid Scleral
Venous plexus
Superior Vena Cava
Anastamose
2. Inferior Ophthalmic Vein
Pterygoid Plexus
3. Facial and Angular Vein
External Jugular Vein

17. Orbital Venous Drainage
Supraorbital v.
Nasofronal v.
Sup. Ophthalmic v.
Nasal v.
Cavernous sinus
Inf. Ophthalmic v.
Angular v.
Infaorbital v.
Ant. Facial v.
Pterygoid plexus

18. Differential Diagnosis?
69 yo female with previous diagnosis of POAG
Elevated IOP OS>OD
Engorged episcleral veins OS>OD
Blood in Schlemm’s canal OS
Differential Diagnosis?

19. Differential Diagnosis
Venous Obstruction
a. Thyroid Ophthalmopathy
b. Superior Vena Cava Syndrome
c. Retrobulbar Tumor
d. Cavernous Sinus or Orbital Vein Thrombosis
e. Episcleral or Orbital Vein Vasculitis
Arteriovenous Anomalies
a. Carotid-Cavernous Fistula
b. Carotid-Dural Fistula
c. Sturge Weber Glaucoma
d. Orbital Varix
3. Idiopathic

20. Additional History
Despite 360o ALT OU and maximal medical
therapy IOP has never been significantly lowered
Patient reports that she has experienced
episodic tinnitus in the left ear

21. Additional Testing?

22. Auscultation: No orbital bruit appreciated Cerebral Angiogram:
Additional Testing
Hertel: Base 96mm
OD:16mm
OS:17mm
Auscultation: No orbital bruit appreciated
Cerebral Angiogram:
Unremarkable anterior and posterior intracranial circulation.
No evidence of carotid cavernous fistula
No evidence of flow-limiting stenosis, aneurysm, occlusion, or
malformation.

23. Idiopathic Elevated Episcleral Venous Pressure
Presentation:
Typically presents in elderly with no FH
Most cases are unilateral
Familial cases have been reported but typically sporadic
Often have previous diagnosis of POAG
Often complain of red eye

24. Idiopathic Elevated Episcleral Venous Pressure
Signs/Symptoms:
Elevated IOP despite medical therapy
Tortuous dilated episcleral veins
Open-angle glaucoma with characteristic nerve and fields
Blood in Schlemm’s canal on gonioscopy
No exophthalmos
Ruled out other etiologies of increased EVP

25. Idiopathic Elevated Episcleral Venous Pressure
Diagnostic Testing:
Orbital ultrasound/MRI: Evaluate retrobulbar space
MRA: Detect carotid-cavernous or dural-cavernous fistula
Carotid Angiography: Gold standard to rule out fistula
Endocrine workup: Evaluated for Thyroid eye disease
Hertel: Detect exophthalmos
Auscultation: Detect orbital bruit

26. Idiopathic Elevated Episcleral Venous Pressure
Management:
Medical:
b-blockers
a2 agonists
Carbonic Anhydrase inhibitors
Surgical:
Trabeculectomy
Tube Shunt
Nonpenetrating deep sclerectomy
Increased risk of uveal effusion and expulsive hemorrhage
Recommended that prophylactic sclerotomies be routinely performed during surgery

27. Our Patient
Follow up visit 10/26/06:
IOP OD:22 OS:30
Follow up 11/15/06:
IOP OD:22 OS:34
Elected to proceed with ExPRESS mini glaucoma
shunt procedure.

28. ExPRESS Mini Glaucoma Shunt
Biocompatible miniature stainless steel implant
Previously placed directly beneath conjunctiva but caused many
complications
In newer technique shunt is placed beneath a scleral flap
Diverts aqueous humor to a subconjunctival filtration bleb

29. A 6 × 3 mm fornix-based conjunctival flap is created in the upper quadrant.

30. A 50% depth, 5 × 5 mm limbal-based scleral flap is created. Mitomycin C
may be applied beneath the flap at the surgeons discretion

31. With a 26-gauge needle, a pre-perforation is made into the anterior chamber under the
scleral flap, in the center of the blue-gray transition zone between the white sclera and
clear cornea.

32. The glaucoma drain is inserted into the anterior chamber via the perforation site.

33. The scleral flap is then securely sutured with 10-0 nylon sutures.

34. The conjunctiva is sutured back in place with 1 or 2 buried 8/0 absorbable sutures.

35. ExPRESS Mini Glaucoma Shunt
Ex-PRESS implant inserted in 24 eyes of 23 patients with severe OAG
Sixteen eyes of the 24 (66%) had had previous failed filtering surgery
Remaining 8 eyes (33%) were high risk for failures cases
IOP was reduced from 27.2 ± 7.1 mm Hg pre-op to:
14.5 ± 5.0 mm Hg at 12 months (n = 21)
14.2 ± 4.2 mm Hg at 24 months (n = 8)
Two patients needed anti-glaucoma meds to keep IOP below 21 mm Hg
Dahan et. al. Implantation of a Miniature Glaucoma Device Under a Scleral Flap. Journal of Glaucoma. April 2005.
14(2):

36. ExPRESS Mini Glaucoma Shunt
Dahan et. al. Implantation of a Miniature Glaucoma Device Under a Scleral Flap. Journal of Glaucoma. April (2):

37. ExPRESS Mini Glaucoma Shunt
Dahan et. al. Implantation of a Miniature Glaucoma Device Under a Scleral Flap. Journal of Glaucoma. April (2):

38. Take Home Points
Understand the venous drainage of the orbit and how abnormalities can result
in elevated EVP and thus elevated IOP.
Be suspicious of elevated EVP in patients previously diagnosed with POAG.
Know the possible causes of elevated EVP and how to evaluate for each.
Be aware that the ExPRESS mini glaucoma shunt is a new procedure that
appears to be safe and effective at lowering IOP in Glaucoma patients when
placed beneath a scleral flap.

39. References Allingham et al. Shields’ Textbook of Glaucoma p.347-352
Clayton et al. CT angiography and MR angiography in the Evaluation of Carotid Cavernous Sinus Fistula Prior to Embolization: A Comparison of Techniques. Am J Neuroradiol. 26: October 2005.
Dahan et al. Implantation of a Miniature Glaucoma Device under a Scleral Flap. J Glaucoma 2005;14:
Greenfield et al. Glaucoma associated with elevated episcleral venous pressure.
J Glaucoma :
5. John et al. Dural and Carotid Cavernous Sinus Fistulas. Ophthalmology 94:
6. Moses et al. Mechanism of Glaucoma secondary to increased venous pressure. Arch Ophthalmol. 1985;103:1701.
7. Talusan et al. Increased Pressure of dilated episcleral veins with open-angle glaucoma without exophthalmos. Ophthalmology 1983;90:257.