New IOL respects the individual anatomy of the capsular bag

PARIS — The Quatrix Evolutif implant from Croma has unique capabilities for adapting to capsular bags of different diameter, without causing deformations with consequent ovalization, capsular folds, imprecise refraction, unnatural expansions of the capsular bag diameter beyond the limits of the ciliary ring and consequent loss of pseudoaccommodation capabilities.

"We have demonstrated by in vivo high-frequency ultrasound imaging that size and position of the crystalline lens and capsular bag vary between individuals," OSN Europe/Asia-Pacific Edition Editorial Board Member Philippe Sourdille, MD, said during a symposium at the meeting of the French Society of Ophthalmology.

Crystalline lens diameter has been shown to vary between approximately 8 mm and 10 mm.

"This variability has practical consequences on the design and sizing of intraocular lenses, which can perform well only if the individual anatomy of the eye is respected," he said.

Another important factor, which is often overlooked, is the relationship between the crystalline lens diameter and the ciliary ring. In 80% of the cases, crystalline lens diameter appears to be equal to or less than the diameter of the ciliary ring.

"Respecting this natural balance when an IOL is implanted is critical to the preservation of pseudoaccommodative movements, but our observations have shown that in the majority of cases IOL implantation increases the capsular bag diameter and more when loop haptic lenses rather than angle piece lenses are used. In most cases, the relation between capsular bag and ciliary ring diameter is completely reversed," Dr. Sourdille said.

The Quatrix Evolutif implant, he said, has been designed to address this need of true customized sizing.

As previous studies have demonstrated, the diameter of the capsular bag is correlated with corneal power and axial length. In a myopic eye, which has a greater axial length and a lower refractive power, a larger diameter IOL will be required, while a progressive decrease of IOL diameter will be calculated in relation with the increase in lens power and decrease in axial length.

"This customized, progressive variation enhances the performance of the implant tremendously and never causes the capsular bag to reverse the natural anatomical relationship with the ciliary ring," Dr. Sourdille said.