New treatment options for pseudophakic aqueous misdirection syndrome (AMS) are showing promise, offering relief to patients struggling with this rare complication following cataract surgery. A recent case series involving twelve patients at the University Hospital of Bern, Switzerland, sheds light on effective approaches to managing AMS, which can lead to severe complications, including vision loss.
Pseudophakic AMS, commonly referred to as malignant glaucoma, is recognized as one of the potential repercussions of cataract surgery. It results from abnormal fluid dynamics within the eye, leading to significant increases in intraocular pressure (IOP). The research team conducted the study on patients diagnosed between December 2021 and November 2022, discovering onset of AMS could occur as long as 2920 days after surgery.
According to the authors, "AMS is a rare but serious complication after cataract surgery, which can occur many years later." The underlying causes and mechanisms of AMS are not fully understood but involve disruptions to aqueous humor flow due to anatomical changes after surgery. Patients often present with flat anterior chambers and elevated IOP, which can be mistaken for other conditions such as acute angle closure glaucoma.
The management of AMS typically begins with medication aimed at lowering IOP, but as reported by the study, "treatment with IOP-lowering medication alone was non-sufficient in all followed cases." This lack of responsiveness often necessitates surgical intervention. The effectiveness of laser iridotomy (LIT) was evaluated, with the authors stating, "While LIT can be tried as first line treatment, pars plana vitrectomy with irido-zonulectomy is often required to control IOP." This means additional procedures are frequently needed to restore normal ocular conditions.
Of the twelve patients involved, four were treated with LIT, with three successfully having their conditions resolved. Those for whom LIT was insufficient underwent vitrectomy combined with irido-zonulectomy. Despite surgical intervention being successful for controlling IOP, the research recorded complications arising postoperatively. The most frequent complication reported was cystoid macular edema (CME), which occurred in 30% of the cases. The authors noted, "A surprisingly frequent complication after treatment with vitrectomy and iridozonulectomy was occurrence of CME."
The study observed a mean age of 78 years among participants, with the majority being female patients of Caucasian ethnicity. The average time from cataract surgery to symptom onset was 888 days, underscoring the importance of long-term monitoring after ocular procedures. The completion of SD-OCT studies revealed changes correlatively associated with IOP management and the onset of CME.
Historically, CME can develop after intraocular surgeries due to inflammation disrupting the blood-retina barrier, but it appears especially pronounced following vitrectomy for AMS. Consensus suggests treatment for CME typically involves topical non-steroidal anti-inflammatory drugs or corticosteroids, yet there were cases requiring more aggressive interventions such as intravitreal steroid administration.
Overall, this case series advocates for heightened awareness surrounding pseudophakic AMS and its treatment pathways. With AMS presenting as both rare and complex, the researchers conclude by emphasizing the need for larger studies to confirm their findings, especially concerning the relationship between surgical treatment of AMS and subsequent development of CME. Through comprehensive examination and conscientious management, clinicians can effectively address this challenging syndrome and improve outcomes for their patients.