Angle-supported intraocular lens

Angle-supported Intraocular Lens

An angle-supported intraocular lens (IOL) is a type of lens implant used in ophthalmology, specifically designed to be placed in the anterior chamber of the eye. These lenses are primarily used in cases where the natural lens of the eye has been removed, such as during cataract surgery, and where posterior chamber lens implantation is not feasible.

Design and Structure

Angle-supported IOLs are designed to rest in the anterior chamber of the eye, with their haptics (supporting arms) positioned in the iridocorneal angle. This design allows the lens to be securely held in place without the need for sutures or additional support structures.

Materials

These lenses are typically made from biocompatible materials such as polymethyl methacrylate (PMMA) or hydrophilic acrylic, which are well-tolerated by the eye and minimize the risk of inflammation or rejection.

Haptic Design

The haptics of angle-supported IOLs are often flexible and designed to conform to the natural curvature of the anterior chamber, providing stability and reducing the risk of damage to the corneal endothelium.

Indications

Angle-supported IOLs are indicated in cases where posterior chamber IOLs cannot be used, such as:

• Aphakia without sufficient capsular support.
• Secondary lens implantation in eyes with compromised posterior capsule.
• Anterior chamber anomalies where traditional posterior chamber IOLs are contraindicated.

Surgical Procedure

The implantation of an angle-supported IOL involves several key steps:

1. Incision: A small incision is made in the cornea to allow access to the anterior chamber. 2. Lens Insertion: The IOL is carefully inserted through the incision and positioned in the anterior chamber. 3. Positioning: The haptics are gently maneuvered into the iridocorneal angle to ensure stable placement. 4. Closure: The incision is closed, often with self-sealing techniques or sutures if necessary.

Complications

While generally safe, angle-supported IOLs can be associated with certain complications, including:

• Corneal endothelial damage: Due to proximity to the cornea, there is a risk of endothelial cell loss.
• Increased intraocular pressure: Improper positioning can lead to angle closure and elevated intraocular pressure.
• Inflammation: As with any intraocular procedure, there is a risk of postoperative inflammation.

Advantages and Disadvantages

Advantages

• Ease of implantation: The procedure is relatively straightforward and can be performed quickly.
• No need for capsular support: Ideal for cases where the posterior capsule is compromised.

Disadvantages

• Risk to corneal endothelium: Proximity to the cornea can lead to long-term endothelial cell loss.
• Limited use: Not suitable for all patients, particularly those with narrow angles.

History

Angle-supported IOLs have been used since the early days of intraocular lens implantation. They were among the first types of IOLs developed and have evolved significantly in terms of design and materials to improve safety and efficacy.

Also see

• Intraocular lens
• Cataract surgery
• Posterior chamber intraocular lens
• Phakic intraocular lens