clinical challenges
A Surprising Spike in IOP
Diagnosing an unusual glaucoma complication takes some detective work.

There is an old adage: common things happen commonly and rare things happen rare-ly. Generally I believe this is true when dealing with ocular dis-ease. But there is also a saying: "It ain't rare if it's in your chair." As you'll see from this case, that's true sometimes as well.

A 57-year-old African-American was a long-standing patient. I had been treating him since 1995 for a rather unusual case of normal tension glaucoma (NTG). He had no family history of glaucoma at the time of his original referral to me. He had very large optic nerve heads with a cup-to-disc ratio (C/D) of 0.7/0.6 OU, but he was a 2.50D hyperope. In addition, the cupping was very deep and much lamina cribrosa was visible OU. The anatomy of the optic nerve head (ONH) looked very suspicious for glaucoma. This was borne out when repeated visual field tests revealed subtle yet consistent Seidel's scotomas breaking out of the blind spot superiorly OD and OS. I followed him for ten months without treat-ment. Over that time, the patient also developed a notch at 2:00 on the neuroretinal rim of his left eye. Yet his intraocular pressure (IOP) stayed between 16 and 18mm Hg OU, depending on the time of day. Even without the benefit of corneal thickness data, (we did not know its value in the diagnosis of NTG yet), the patient clearly had NTG. Because the patient was young and had developed visual field defects early in the course of the disease, I set a rather aggressive target pressure of 11mm Hg. I was able to achieve an IOP of <12mm Hg OU consistently, after some trials, using Lumigan (bimataprost, Allergan) OU q.h.s. The glau-coma follow-up reports show no further progression of the neuroretinal rim defects since.

This stereo photograph shows three keratic precipitates on the inferior corneal endothelium.

The strange gets stranger

I continued to see the patient for regular glaucoma care. He maintained 20/20 vision, stable neuroretinal rims, stable VF and IOP routinely measured 11mm Hg or lower. He returned in the spring of 2005 for one of his regularly scheduled exams. He reported no difficulty with his eyes or vision and that he was using the drops as prescribed. However, visual acuity was 20/30 OD and did not improve with pinhole occlusion. There was no change OS.

In the exam room, I asked whether he felt any pain or discomfort in his right eye or if he had noticed any change in vision, specifically in his right eye. He rather begrudgingly admitted that it did "feel kind of funny" but that it did not overtly hurt. Pupils were equally round and reactive and measured 4mm in size, consistent with his past exams. Extraocular muscles showed full range of movement and the patient reported no pain when he moved his eyes. Visual acuity OS did not improve upon refraction. A surprising slit lamp exam revealed very mild bulbar conjunctival injection and three small, yet distinct keratic precipitates (KP) on the posterior corneal endothelium OD. The anterior chamber revealed 1+ cells but no flare (see image on page 26) and I estimated the angle to be a Grade 3 using the Von-Herick method. There were no posterior synechiae but there was a mild anterior capsular cataract, which was stable from previous visits. Examination with a slit lamp OS revealed a white, quiet eye with a well-formed anterior chamber and no reaction. My surprise continued when I meas-ured his IOP at 42mm Hg OD and 14mm Hg OS.

The hunt for a cause

Whenever I see a patient with an acutely elevated IOP, my first thought is that an acute angle closure attack is occurring. Typically, acute glaucoma is marked by a very painful eye and decreased vision, although there are some exceptions to this, such as in cases of a sub-acute attack. However, in angle closure glaucoma, the anterior chamber angle is always closed. I placed a gonioscopy lens on the patient's right eye and noted that the angle was open. I was easily able to view the scleral spur 360 degrees in both eyes, thus ruling out angle closure glaucoma. Just as significantly, I noted that there were no peripheral anterior synechiae OU and no neovascular vessels in the angles, which helped to rule out inflammatory glaucoma and neovascular glaucoma. Having safely ruled out acute angle closure glaucoma, I proceeded to dilate the patient's eyes. His ONH appeared unchanged from previous examinations. I judged them to be 0.8/0.65 OD and 0.75/0.7 OS. More importantly, there were no disk vessels or collaterals and the vitreous was free of cells. There was no pars planitis or snow banking evident, which basically ruled out inflammatory open angle glaucoma.

During my examination, I had ruled out acute angle closure glaucoma, inflammatory glaucoma and neovascular glaucoma. There was no pigment clogging the anterior chamber angle and none on the corneal endothelium, so it couldn't be an extreme case of pigmentary glaucoma. On the basis of exclusion I felt that the patient was presenting with a glaucomatocyclitic crisis.

Easy for you to say!

Glaucomatocyclitic crisis, otherwise known as Posner-Schlossman Syndrome, is characterized by an acute unilateral IOP elevation and a mild (Grade 1) anterior chamber reaction. There will be little pain and the eye itself is generally white or with minimal bulbar conjunctival injection. There may be very few, if any, keratic precipitates and the anterior chamber remains open and free of synechiae, which I feel is a distinguishing factor. The patient's symptoms will include mild blurred vision, due to corneal edema, or slight ocular discomfort due to the mild iritis.

Once diagnosed, the treatment is straightforward. The goal is twofold: to lower the IOP and resolve the anterior chamber reaction. Since this patient was already using Lumigan for his NTG, I added Betimol 0.5% (timolol hemihydrate, Vistakon) b.i.d. OD. I also prescribed Pred Forte (predniso-lone acetate 1%, Allergan) OD q.i.d. and set up a follow-up appointment for three days.

At the first follow-up visit, the patient's condition had markedly improved. He stated that he felt no discomfort OD and the VA had improved to 20/25 +2 OD. The anterior chamber reaction had completely resolved but two tiny KPs remained. The IOP had dropped to 17mm Hg OD and 15mm Hg OS. I opted to continue the Betimol and Lumigan as prescribed but began to taper the steroid. I told him to use the Pred Forte drop t.i.d. OD for five days, then b.i.d. for five days and to return to the office in ten days. At that exam, his VA had returned to 20/20 –2 OD and IOP measured 13mm Hg OU. There was no anterior chamber reaction and no residual KPs. I instructed the patient to discontinue the Betimol and to use the Pred Forte q.d. for five more days before stopping. I also asked him to continue with the Lumigan OU q.h.s.

In the seven months since this occurred, there has been no recurrence of the condition. However, the patient's IOP stayed around 13mm Hg OU, so I added Alphagan P (brimonidine, Allergan) OU b.i.d. to the Lumigan. On dual therapy his IOP consistently hovers at 11mm Hg or less and his NTG is once again well controlled.

CLINICAL PEARLS

►Glaucomatocyclitic crisis is a diagnosis based on exclusion. First rule out angle closure glaucoma, neovascular glaucoma and inflammatory glaucoma.

►Glaucomatocyclitic crisis is always unilateral, although it can recur in the contralateral eye.

►Gonioscopy is key to making the correct diagnosis; the anterior chamber angle will be open and free of any synechiae. The angles should appear similar OU.

►Glaucomatocyclitic crisis is considered self-limiting. However, I choose to treat the condition to alleviate any chance of optic nerve disease, especially in patients who have pre-existing glaucoma.

►To lower IOP, use a topical agent that suppresses aqueous humor production. Beta-blockers are very effective at this. Topical carbonic anhydrase inhibitors act in the same manner if the patient has a contraindication to beta-blockers.

►Generally, avoid prostaglandins in cases with an anterior chamber reaction. Prostaglandins have been shown to precipitate cystoid macular edema especially in inflamed eyes. I chose to leave this patient on the prostaglandin simply because it had previously been the most effective agent to control his IOP. It certainly would not have been remiss to discontinue Lumigan during the acute process.

►Taper the steroid very quickly in these patients. They generally respond extremely well and can be weaned off it rapidly. Also, an initial dosing schedule of q.i.d is usually sufficient to quiet the anterior chamber reaction.

Contributing Editor Dr. Schmidt is director of the Bladen Eye Center in Elizabethtown, N.C. E-mail him at schmidtyvision@bellsouth.net.