OD News Articles

1st October 2018

Complex Cataract Surgery

by Abigail Neal, OD Tacoma, WA

As eyecare providers, it’s wonderful to see perfect surgery candidates—those with good systemic health, pristine ocular health, and no prior eye injuries. But often that’s not the case. We are fortunate to have excellent surgery techniques to use when cataract treatment is more difficult than usual. And in reality, it is frequently the complex procedures that give us the most rewarding outcomes. Join me in a review of some of the options our surgeons can turn to when faced with challenges.

A man rides his bike

IOL Locations

There are many situations where IOLs need to be placed in different locations within the eye.

These include:

  • Previous trauma, including blunt or penetrating injury
  • A history of previous inflammation or infectious processes like uveitis or endophthalmitis
  • Systemic disorders such as Marfan’s syndrome or pseudoexfoliation
  • Complications during cataract surgery that lead to capsular compromise or loss
  • The absence of capsular support when a lens replacement or secondary IOL is required

Research shows that if there is some capsular support, it is best to place IOLs in the sulcus—with or without optic capture. When this is not an option, alternative approaches include:

  • Anterior chamber IOL placement
  • Iris-fixated IOLs
  • Scleral-fixated IOLs

Each technique has pros and cons, and most have undergone significant modifications and improvements over the years.

    Close-up of eye with ACIOL

    ACIOL in a patient with a history of aphakia after congenital cataract extraction and contact lens intolerance.
    Click here for copyright and licensing info.

Anterior Chamber IOLs

Anterior chamber IOLs are placed in front of the iris with the haptics located in the iridocorneal angle. This approach is often the least complex. And some of the newer ACIOL designs have an improved safety profile.

Disadvantages include increased risk of:

  • Glaucoma from structural angle changes
  • Iris damage/chafing
  • Chronic inflammation
  • Cystoid macular edema
  • Corneal decompensation

ACIOLs are made of polymethylmethacrylate (PMMA). This rigid, non-folding material requires a larger incision that can result in more bleeding and longer healing time. The larger incision may also need sutures which can induce astigmatism.

Iris-Fixated IOLs

Iris-fixated lenses can be secured with several techniques:

  1. They can be placed behind the iris with sutures located in the mid-periphery of the iris. Positioned in the posterior chamber, the risk of corneal decompensation and alteration of the angle anatomy is reduced.
  2. A much older, less frequently used technique utilizes an iris-claw lens that is placed anteriorly or posteriorly. Specially designed haptics grasp the iris tissue. Mid-peripheral iris fixation can decrease the risks of angle compromise. However, the risk of endothelial decompensation over time remains.

Potential disadvantages include:

  • A more challenging surgery, especially if the IOL is sutured to the iris
  • Distortion or damage to the iris structure
  • Chronically poor dilation
  • Risk of inflammation due to the IOL rubbing against the iris
  • Cystoid macular edema
  • Increased intraocular pressure
Scleral-Fixated IOLs

Scleral-fixated IOLs can be positioned by fixing the haptics through the ciliary sulcus or pars plana to the sclera. This can be done with sutures, by gluing the haptics under scleral flaps, or by utilizing a sutureless and glueless technique.

Advantages:

  • Avoids potential anterior-chamber complications
  • Can make IOL power easier to calculate as the lens is positioned close to where an IOL within the capsule would be located
  • Eliminates potential distortion or damage to the iris tissue

Potential disadvantages include:

  • Risk of suture breakage/erosion over time
  • Lens tilt
  • Suprachoroidal hemorrhage
  • Hypotony due to wound leak through the sclerotomies
  • Retinal detachment
  • Secondary glaucoma
Transconjunctival Sutureless Intrascleral Iol Fixation

A very promising modification of sutureless scleral fixation is the double- needle technique. The eye is marked on either side of the limbus with a special skin dye 180 degrees apart to identify the sclerotomy sites.

After cataract removal, a 3-piece foldable IOL is inserted. A special 30-gauge needle is used to create the first sclerotomy, and the first haptic is guided into the lumen of the needle. A second needle is then used to create the second sclerotomy 180 degrees away, and the second haptic is guided into the lumen of the second needle.

Once the IOL is properly positioned, the needles are simultaneously withdrawn, externalizing both haptics. A cautery is held close to the tip of each haptic. A mushroom-shaped flange forms at the end of the haptics as the material melts from cautery. This flange prevents the haptics from dislocating into the eye. The haptic is gently pushed flush with the sclera and covered with conjunctiva.

    IOL surgery being performed
    Once the IOL haptics are pulled through the sclera, the ends are melted slightly with cautery heat. These small flanges are then securely fixed within the sclera
Advantages:
  • No risk of suture breakage or erosion over time
  • Decreased risk of corneal decompensation, iris/angle damage, chronic inflammation from IOL/iris contact, and secondary glaucoma
  • Less damage to the uveal tissue, decreasing the risk of postoperative hypotony, suprachoroidal hemorrhage, and hemorrhage during surgery

Some of the more common complications are:

  • Lens tilt or decentration
  • Iris capture

Conclusion

When lens capsules are compromised, surgeons have various methods and techniques to position an IOL. There is not enough evidence to show that one technique is superior to another. So the decision is often based on the patient’s co-existing ocular pathology and the technique the surgeon is most comfortable performing.

Questions?

If you ever have questions, feel free to contact any of our optometric physicians. We’re always happy to help.