During cataract surgery, it is necessary to dilate the iris in order to remove the crystalline lens and position the implant. The diameter of the optical implant being 6 mm, in case of capsulorhexis crystalline access 5.5 mm, the expansion should be at least 6 mm.

At pre-operative consultation, the iris is always dilated by instillation of eye drops and measured at the slitlamp. For patients with an inadequate dilation, the intervention requires the use of a mechanical dilatation device.

This study aims to assess the value of an alternative dilatation ring to Malyugin ring, which can be inserted and removed through an incision of less than 2 mm in diameter, due to its size smaller than that of the Malyugin ring.

Our hypothesis is that this Bhattacharjee ring ensures sufficient and stable iris dilation during surgery, enabling implant placement in good conditions.

Inclusion Criteria:

• Patient with programmed cataract surgery under topical or local anesthesia
• Need to use a dilatation ring during operation, highlighted by iris dilatation ≤ 6 mm on slitlamp, after mydriatic solution and 10% phenylephrine eye drops instillation

Exclusion Criteria:

• Pregnant or breastfeeding woman
• Patient's refusal to participate in the study
• Patient non covered by health insurance
• Complete iridectomy
• Tearing of iris sphincter
• Important posterior synechiae (when the iris is attached to the anterior surface of the implant)
• Anterior chamber very deep (depth of the anterior chamber lower than 1mm after injection of the viscous product)