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Editor,—Determination of the mechanism of acutely elevated intraocular pressure is extremely difficult if not impossible in the presence of impaired transparency of the anterior ocular segment. Ultrasound biomicroscopy (UBM), a high resolution (50 MHz) ultrasonographic technique, can be helpful in determining the underlying mechanisms in such a case.12
A 61-year-old man presented with severe pain and profound visual impairment in his right eye. Ophthalmic examination revealed visual acuities of hand movement in the right eye and 20/30 in the left. Intraocular pressure (IOP) was 53 mm Hg in the right eye and 14 mm Hg in the left. Slit lamp biomicroscopy and gonioscopy of the left eye revealed a clear cornea, deep anterior chamber, normal iris, and wide open angles. In contrast, the right eye showed generalised corneal oedema and turbid aqueous with 4+ cellular reaction and a 2 mm hypopyon. The anterior chamber appeared deep; however, the angle structures could not be visualised on attempted gonioscopy (Fig 1). The left ocular fundus was unremarkable, but the right fundus could not be visualised.
Review of the patient’s medical history elicited report of a ‘brain tumour’ and ‘metastatic cancer in the lungs’. We were concerned about the possibility of metastatic carcinoma to the iris or ciliary body as the underlying mechanism.
B-scan ultrasonography of the right eye revealed a dense cataract and particulate intravitreal echoes consistent with inflammatory cells but no retinal detachment, choroidal detachment, intraocular tumour, or foreign body. UBM of the right eye, using the Humphrey UBM 840 system (Humphrey Instruments Inc, San Leandro, CA, USA), demonstrated a deep anterior chamber, open angles, and multiple cells and cell clumps in the aqueous. The lens appeared to be elongated but thin and exhibited capsular wrinkling and thickening (Fig 2). There was no evidence of focal or diffuse nodularity of the iris or ciliary body. The mechanism of acute intraocular pressure elevation and inflammation was therefore assumed to be phacolytic glaucoma.
The patient was treated medically with topical anti-inflammatory and antihypertensive medications until urgent uneventful extracapsular cataract surgery with posterior chamber lens implantation could be performed. Visual acuity recovered to 20/60, intraocular inflammation resolved, and IOP returned to normal without medications. Unfortunately, he died of complications related to his cancer 6 weeks after surgery. The eye was not obtained post mortem.
Diagnostic considerations in a patient with acutely elevated IOP associated with hypopyon and a medical history of active metastatic cancer include microbial forms of inflammation related to immunosuppression, metastatic carcinoma to the iris and ciliary body, and non-microbial forms of inflammation, such as lens induced uveitis, unrelated to the neoplastic disorder. Conventional B-scan ultrasonography did help partially to clarify the differential diagnosis by ruling out a posterior segment tumour. UBM revealed partial collapse of the lens, indicative of probable liquefaction of the lens cortex, leakage of lens material into the aqueous, and showed no evidence of metastatic processes. UBM findings were complementary to the conventional B-scan ultrasonography in this case and led to the presumptive diagnosis of phacolytic glaucoma and subsequent prompt, appropriate, and effective treatment for this disorder.3
In eyes with acutely elevated IOP and opacification of the anterior optical media, UBM should be considered a potentially helpful diagnostic adjunct.