Opacification of hydrophilic acrylic IOL spurred patient recall in Malaysia

Investigators found a correlation between pre-existing diabetes mellitus and lens opacification.

Andrew Keat Eu Lim

A hydrophilic acrylic IOL was associated with a relatively high rate of opacification, resulting in a patient recall in Malaysia, a study found.

The recall stemmed from three reported cases of opacification in the AcriFlex 50CSE IOL (Acrimed). Patients received the implant in 2005 and 2006.

The study was published in the Journal of Cataract and Refractive Surgery in 2011. Results were also presented at the 25th Malaysia-Singapore Joint Ophthalmic Congress in Kuala Lumpur in 2009.

Opacification apparently resulted from deposits of calcium and phosphate on IOL surfaces, the study authors said.

The pathophysiology of opacification is unknown. However, the authors found a strong correlation with pre-existing diabetes mellitus.

Previous studies have shown an elevated risk of opacification in hydrophilic acrylic IOLs, the authors said.

“From the literature, hydrophilic acrylic is more prone to opacification,” Andrew Keat Eu Lim, FRCS, the corresponding study author, said in an email interview with Ocular Surgery News. “We think it is related to a breakdown in the blood-aqueous barrier.”

All ophthalmologists in Malaysia were directed to refrain from implanting the AcriFlex IOL. Clinicians were unable to persuade the manufacturer to investigate possible causes of opacification. The lens importer agreed to cease marketing the implant.

Recall and evaluation

The AcriFlex 50CSE was a single-piece, three-haptic IOL made of hydroxyethyl methacrylate, a hydrophilic poly copolymer. It had a biconvex optic diameter of 6 mm and an overall diameter of 10.5 mm. The implant received CE 1275 certification.

After the cases of opacification were reported in 2006 and 2007, hospital personnel identified a total of 376 eyes of 324 patients who had received the AcriFlex 50CSE IOL; 18 patients had died. Staff telephoned or wrote letters to the 306 surviving patients to inform them of the recall; 67 patients could not be contacted or declined examination.

Ultimately, 239 patients (78.1%) attended clinic appointments. Mean patient age was 64.8 years; 127 patients were of Chinese descent, 83 were Malay and 29 were East Indian.

The high patient response rate was attributed to the use of electronic medical records and the involvement of a registry manager who maintained a patient database and contacted patients targeted for recall.

Patients underwent ophthalmic and systemic evaluation, particularly for diabetes mellitus because the IOL insert included a warning against implantation of the IOL in diabetic patients.

Investigators recorded, when applicable, time between IOL implantation and identification of opacification, time between implantation and explantation, and duration of follow-up after explantation.

An IOL was deemed opacified if it appeared hazy and not fully transparent on slit lamp examination. IOL opacification was not graded.

Findings, conclusions

Investigators identified IOL opacification in 14 eyes of 13 patients (5.4%). Seven lenses with sufficient opacification to cause significant visual disturbances were explanted and subjected to scanning electron microscopy and energy-dispersive X-ray spectroscopy.

Scanning electron microscopy showed hyperluminous areas on the IOL surface. These areas comprised crystalline deposits resembling calcium. Energy-dispersive X-ray spectroscopy confirmed the presence of calcium and phosphate deposits on the lens optics and haptics and traces of silicone and aluminum on the vertical haptic surface of one lens, the authors said.

Only patients with symptomatic opacification and an understanding of surgical risks qualified for IOL explantation. Explanted IOLs were replaced with different implants at no cost to patients.

The mean interval between cataract surgery and opacification was 28.7 months.

“We looked at the relationship between time and severity but couldn’t find any,” Dr. Lim said. “Severe opacification can occur earlier, and patients with previously clear IOLs can suddenly opacify quickly.”

Results showed that nine patients with IOL opacification (69.2%) and 83 patients with clear IOLs (36.7%) had diabetes mellitus. Diabetes was identified as a significant risk factor for IOL opacification (P = .019), the authors said.

Opacification in diabetic patients may be attributable to a metabolic imbalance, altered fluid dynamics of aqueous, deterioration of the blood-aqueous barrier and other factors, the authors said.

Data were not sufficiently powered to show a possible association between IOL opacification and glaucoma.

Patients who received the AcriFlex 50CSE IOL will be monitored for at least 5 years to allow identification of emerging cases of opacification, the authors said. – by Matt Hasson

Reference:

• Lim AKE, Goh PP, Azura R, Mariam I. Opacification of AcriFlex 50CSE hydrophilic acrylic intraocular lens. J Cataract Refract Surg. 2011;37(4):655-659.

• Andrew Keat Eu Lim, FRCS, can be reached at Department of Ophthalmology, Penang Hospital, Jalan Residensi, 10990 Penang, Malaysia; email: akelim@yahoo.com.
• Disclosure: Dr. Lim and colleagues have no relevant financial disclosures.