Man presents with unilateral ocular hypertension
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A 60-year-old man presented to the New England Eye Center as a same-day walk-in to the glaucoma clinic to establish care after having relocated to the Boston area.
He denied any visual symptoms, headaches, double vision, flashes, floaters, pain or difficulty with extraocular movements. Full review of symptoms was notable only for anxiety.
His ocular history included treatment of ocular hypertension with timolol and brimonidine in his left eye for more than 10 years. He reported poor compliance with his drop regimen in the past. He denied a history of pediatric ophthalmic care.
His medical history included coronary artery disease status post cardiac stenting, ischemic cardiomyopathy status post implantable cardioverter defibrillator placement, high cholesterol and anxiety. His home medications included aspirin, sacubitril/valsartan, simvastatin, carvedilol, aldactone, ferrous sulfate and ranitidine.
His family history was significant for depression and bipolar disorder in a sibling and colon cancer in his father. He was an unmarried retired salesman and current smoker, and he consumed six to eight alcoholic beverages per week.
Examination
On exam, the patient’s vision was 20/20 with correction in both eyes. Pupil exam was normal. IOP by applanation was 14 mm Hg in the right eye and 24 mm Hg in the left eye. Confrontation visual fields were full, and extraocular movements were normal.
Anterior segment exam in the right eye showed mild guttae and trace nuclear sclerosis. In the left eye, there were dilated, tortuous episcleral vessels with telangiectasias. The cornea had a small anterior stromal scar and mild guttae. The iris was normal without transillumination defects or heterochromia. The anterior chamber was deep and quiet, and trace nuclear sclerosis was present.
On gonioscopy, both eyes were open to the ciliary body in all quadrants. However, in the left eye, there was heme reflux noted in Schlemm’s canal, and from 12 to 3 o’clock, there was no trabecular meshwork visible despite an open angle.
Posterior segment exam was remarkable for cup-to-disc asymmetry of 0.2 on the right and 0.45 on the left. Vitreous was clear in both eyes, and no choroidal or retinal lesions were noted in either eye.
External exam was significant for a left-sided periorbital facial hemangioma that extended along the cheek, nose and upper lip.
Humphrey visual fields 24-2 were full in the right eye and showed nonspecific changes in the left eye (Figure 1a). OCT of the retinal nerve fiber layer (RNFL) revealed normal average thickness in both eyes (Figure 1b).
Source: Erin Lanzo, MD, and Chandru Krishnan, MD
What is your diagnosis?
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Ocular hypertension
Our patient’s presentation was notable for unilateral elevated IOP, dilated episcleral vessels and heme reflux in Schlemm’s canal, heightening suspicion for elevated episcleral venous pressure (EVP). Elevated EVP can be considered within three main etiologic categories: venous stasis or congestion, arteriovenous malformation and idiopathic.
Within the first category of venous stasis, one must consider obstruction or disruption of venous flow anywhere along the outflow path. Within the conventional outflow pathway, aqueous flows from the anterior chamber through the trabecular meshwork, Schlemm’s canal, the collector channels, the episcleral veins, the superior ophthalmic vein, the cavernous sinus, the internal jugular vein, the superior vena cava and finally to the right atrium. Obstruction or stasis along this pathway can occur due to a retrobulbar mass, cavernous sinus thrombosis, thyroid eye disease, orbital amyloidosis, superior vena cava syndrome, vasculitis or right-sided congestive heart failure.
Arteriovenous malformations (AVMs), which lead to a high-pressure venous system, are a second cause of elevated episcleral venous pressure. Etiologies include carotid-cavernous fistula, dural arteriovenous shunt, orbital varices, carotid-jugular shunt, orbital-meningeal shunt or large capillary malformations, as seen in Sturge-Weber syndrome (SWS).
Radius-Maumenee syndrome, a diagnosis of exclusion, is an idiopathic cause of elevated EVP.
The patient’s facial angioma is our largest clue to the etiology of his elevated IOP and EVP and makes the diagnosis of SWS most likely. Furthermore, with elevated IOP and an increased cup-to-disc ratio, our patient has evidence of glaucoma in the left eye. He also has evidence of possible angle dysgenesis, which can occur in impaired neural crest cell development in SWS.
Elevated EVP of unknown cause may warrant an extensive workup. Without cutaneous evidence of SWS, such as a facial angioma, head imaging such as CT/CTA or MRI/MRA/MRV may be indicated to evaluate for vascular pathology causing elevated EVP. Cerebral angiography is the gold standard but carries additional procedural risk. Less commonly used in a practical clinical setting, a Doppler ultrasound can confirm dilation of the superior ophthalmic vein, and venomanometer can indirectly measure EVP.
Discussion
Sturge-Weber syndrome, also called encephalotrigeminal angiomatosis, is one of the phakomatoses and is characterized by hamartomas of the brain, skin and eyes. These malformations of normal tissue result from impaired neural crest development during the first 2 weeks of embryologic growth. SWS occurs in approximately one in 50,000 births with no gender predilection.
Its ocular manifestations are many. The characteristic facial angioma (port-wine stain) typically involves the eyelid and periocular skin. The conjunctiva and sclera often develop telangiectatic dilated vessels. Anterior segment findings include iris heterochromia, cataract, angle dysgenesis and accompanying vascular formations within the trabecular meshwork. Angle dysgenesis can result in congenital glaucoma and its associated signs of increased corneal diameter, corneal haze and buphthalmos. In the posterior segment, the presence of diffuse choroidal hemangiomas results in the classic “tomato ketchup” fundus appearance (although, as in our patient, this finding is not always present). Associated retinal findings include serous retinal detachment, photoreceptor degeneration, cystoid macular edema, tortuous vessels and optic disc coloboma. A patient with SWS may have some combination of the above findings, and a normal fundus exam does not exclude the diagnosis.
Glaucoma is a complication of SWS that is especially challenging to manage. It is categorized as a secondary open-angle glaucoma, although there are reports of closed-angle attacks in a small subset of these patients. Age of onset is distributed in a bimodal pattern: roughly 60% of cases are early onset (congenital), usually resulting from angle malformation, and 40% are later onset (adolescence or adulthood), typically attributed to elevated EVP due to capillary AVMs. Glaucoma in these patients is typically unilateral and ipsilateral to the port-wine stain.
There are two main mechanisms underlying the pathophysiology of elevated IOP in SWS. The first mechanism is related to the embryologic malformation of the angle (due to impaired neural crest development and migration), which leads to resistance to aqueous humor outflow at the level of the trabecular meshwork. Typically in severe cases of angle dysgenesis, the patient will present with congenital glaucoma.
A second mechanism of increased EVP induced by AVM and a high-pressure system accounts for later presentation in adolescence or adulthood. These patients typically have a normal open angle with heme in Schlemm’s canal on gonioscopy.
Cases of congenital glaucoma with angle dysgenesis often require early surgical intervention, with goniotomy being the first-line approach. If the eye pressure remains uncontrolled despite goniotomy, trabeculectomy or drainage device placement is necessary, although trabeculectomy is often unsuccessful due to the exuberant healing response typical in young patients. Outcomes are often poor.
In patients with later-onset glaucoma, medical management is appropriate, with topical aqueous suppressants being the preferred approach. Miotics or agents that enhance uveoscleral outflow may also be used. Laser trabeculoplasty is not recommended, as it does not treat outflow resistance at the level of the episcleral venous system. If IOP is not controlled by medications alone, filtering surgery is indicated. However, surgery can be fraught with complication. There is an increased risk for expulsive choroidal hemorrhage, bleeding, postoperative choroidal effusions at hypotonous and non-hypotonous pressures due to elevated hydrostatic pressure within the capillary system, and bleb failure. Intraoperative precautions should be taken to minimize these risks. Options include use of a valved implant to prevent precipitous drop in pressure, two-staged surgery to allow for a fibrous capsule to form around the plate to avoid excessive filtration, use of prophylactic sclerotomies and use of mitomycin C.
Case resolution
Our patient was followed over the course of 7 years and managed medically with brimonidine and dorzolamide-timolol each twice daily in the left eye. He reported poor compliance with therapy and was intermittently lost to follow-up for months or years at a time. His visual fields and OCTs, initially normal and full, showed progression of an inferior nasal step on the left with corresponding superior thinning several years after presentation. His cup-to-disc ratio enlarged to 0.7 with superior and inferior thinning. These changes worsened when he re-presented after having been lost to follow-up for 3 years (Figure 2).
At this point, the decision was made with the patient to attempt Ahmed glaucoma valve (New World Medical) placement with corneal patch graft. There were no complications encountered intraoperatively, and on postoperative day 1, his visual acuity was 20/100 and IOP was 17 mm Hg, with a well-covered plate, formed anterior chamber and tube in good position.
On postoperative day 4, the patient developed choroidal effusions despite an IOP of 19 mm Hg. He had a Seidel-negative wound with an elevated bleb. B-scan ultrasound showed nasal choroidal detachment at a non-hypotonous pressure (Figure 3).
He was initially managed with cycloplegia and prednisone acetate drops every 2 hours while awake. However, the choroidal detachments persisted, requiring reformation of his anterior chamber with viscoelastic twice. By postoperative day 18, the choroidal detachments resolved, and prednisolone was tapered (Figure 4).
His pressures remained between 11 mm Hg and 19 mm Hg during his postoperative course, highlighting the difficulty of managing patients with elevated EVP who develop choroidal detachments at normal pressures.
After resolution of the choroidal detachments, his visual acuity remained at hand motion. He was noted to have a 3+ nuclear sclerotic cataract with 3+ cortical changes. At this time, cataract surgery was recommended, which he underwent successfully less than 2 months after his glaucoma filtering surgery.
One month after cataract surgery, visual acuity in the left eye had improved to 20/40, and IOP was 23 mm Hg. Dorzolamide-timolol twice per day was added back to his regimen, and his pressure has been well controlled since.
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- For more information:
- Erin Lanzo, MD, and Chandru Krishnan, MD, can be reached at New England Eye Center, Tufts University School of Medicine, 800 Washington St., Box 450, Boston, MA 02111; website: www.neec.com.
- Edited by Christine Benador-Shen, MD, and Malgorzata Dymerska Peterson, MD. They can be reached at New England Eye Center, Tufts University School of Medicine, 800 Washington St., Box 450, Boston, MA 02111; website: www.neec.com.