Indications:
Loss of capsular support
Absence of zonules
In these cases, AC IOL can be placed if there is normal iris anatomy and deep angles.
Contraindications:
Preexisting corneal endothelial damage
Iridocorneal angle damage
Shallow AC
Aniridia/ Lack of sufficient iris
Sizing of AC IOL
Earlier models of ACIOL were rigid and closed-loop.
Nowadays, they are typically flexible and open loop with a supporting base at the end of each haptics. These haptics are inserted in the anterior chamber angle against the scleral spur, anterior to the iris.
Accurate measurement of the anterior chamber diameter is important for choosing the appropriately sized ACIOL.
The most common method of sizing an ACIOL is by determining the white-to-white (WTW) diameter and adding 1mm; however, these estimations of angle position vary in accuracy depending on the anatomy of the patient.
Also, the length varies depending on if the surgeon is sitting superiorly or temporally.
Insertion
Standard ACIOLs are made of PMMA and therefore are not foldable.
The lens diameter is typically larger at 6mm, thus requiring a large 6mm incision. A scleral tunnel is often utilized, as it reduces corneal astigmatism from a larger corneal wound. A corneal incision can result in significant irregular astigmatism
Pupil is constricted to pull the iris out of the angle prior to lens insertion.
A peripheral iridotomy is created prior to lens insertion to avoid postoperative iris bombe or pupil block.
A lens glide is used to assist in inserted of the ACIOL.
If the pupil is peaked or oval, it is a sign that the iris is incarcerated in the haptic loops and should be repositioned.
Complications:
Increased chance of causing damage to the angle and iris, which can lead to chronic inflammation, elevated intraocular pressure, uveitis/glaucoma/hyphema syndrome, corneal endothelial damage and corneal decompensation.
Newer, flexible, open-loop models have greatly improved outcomes when compared to older, inflexible closed-loop designs
Image from Rajan Eye Care
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