Aqueous Misdirection Syndrome Following Uneventful Phacoemulsification Surgery

Aqueous misdirection after cataract surgery is a very rare complication and surgical intervention may be necessary. Patient-related risk factors for aqueous misdirection include female gender, short axial lengths, hypermetropia, narrow iridocorneal angles and shallow anterior chamber depths.  The purpose of the study is to present a case of aqueous misdirection in a patient 5 weeks after uneventful cataract surgery. 

Department of Ophthalmology, General Hospital of Lamia, Lamia, Greece

A 75-year-old Caucasian woman underwent uneventful cataract operation with implantation of  EnVista toric intraocular lens (IOL) in the left eye. The patient had no past ocular history and presented with bilaterally normal intraocular pressure (12mmHg) and normal optic disc. The anterior chamber was of moderate depth in both eyes. The spherical component of the IOL was 27.0 D (SRK/T formula), aiming for a postoperative refraction of -0.75 sph. 15 days after surgery the patient presented with acute angle closure and intraocular pressure rise (30mmHg) in the fellow (right) eye and treated accordingly. At that time postoperative refraction in the left eye was -1.75 sph with normal anterior chamber depth. 20 days after acute angle closure the patient complained about vision blurring in the left eye. Refractive correction revealed a myopic surprise (-3.00 sph), with rather shallow anterior chamber, angle closure 270o and left eye intraocular pressure of 40 mmHg. The patient was commenced on coll Atropine q.i.d, coll Phenylephrine q.i.d, coll Tobradex q.i.d, tab Acetazolamid t.i.d. and mannitol IV b.i.d.

The intraocular pressure normalized in 4 days, acetazolamide was discontinued in 7 days and topical treatment was gradually tapered except for coll Atropine. The anterior chamber depth was increased and refractive correction returned to -1.25sph (VA 20/30). 

Clinical presentation of aqueous misdiretction syndrome may be subtle and of fluctuant pattern, with myopic surprise being the only initial presenting sign without elevated intraocular pressure. Biometric measurements of anterior chamber depth (ACD) and intraocular lens calculations in eyes with short axial length mat be inacurate, particularly if the measurements are made when the patient is in absolute or relative aqueous misdirection. Patients who are at risk of aqueous misdirection syndrome should be followed up closely after cataract surgery. The pressure adjustment can also be done conservatively and individually decided how invasive the treatment must be and whether a vitrectomy is necessary.