How I Do Preoperative Evaluations for Complex Cataract Cases

Jul 12, 2021
19 min read
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Advanced surgical instruments and techniques have made modern cataract surgery extremely safe and effective. However, cases complicated by previous trauma, extremely dense cataracts, and pseudoexfoliation still exist—and surgeons should be prepared to tackle these successfully.1-5 Fortunately, tried-and-true preventative measures and intraoperative solutions can help avoid a case from sinking (or the lens for that matter!).

Surgeons should also know their own surgical limitations and refer to a more experienced surgeon if necessary.1-5 Complex cataract cases require vigilance at all stages; surgeons must recognize and anticipate challenges preoperatively, and ensure they have the correct tools in the OR to help manage issues that may arise.1-5 Having a plan and a back-up plan helps the surgeon stay focused and use appropriate techniques to improve surgical success.

This article focuses on key exam findings and diagnoses that can tip a surgeon off for a possible complex case—and how to adequately prepare!

Basic anatomical considerations

Success in any field of surgery depends on a comprehensive, in-depth understanding of anatomy. Understanding the nuances of your operative target (in this case, the crystalline lens) will help you prepare for anatomy anomalies, whether congenital or environmental (e.g., traumatic) in nature. The normal crystalline lens is suspended in its natural position by zonular fibers from the ciliary body.3-5 The lens has a capsule (anterior and posterior), epithelium, cortex, and nucleus.3-5

Straight-forward phacoemulsification-based cataract surgery depends on an uncompromised, centered crystalline lens as well as intact and strong zonules.3-5 Violation of the lens capsule and lens dislocation as well as weakness or loss of zonules can lead to a complex surgery—and even the need for additional surgeries.

Top tools to keep in your cataract surgery toolbox

When evaluating a patient for cataract surgery, there are several entities that may tip you off regarding a possible complex case. These include: pseudoexfoliation syndrome, history of trauma, lens abnormalities, zonular abnormalities or loss, poor dilation (small pupils), extremely long or short eyes as well as very dense brunescent and white intumescent cataracts.1-5 The following is a list of items to have available to you in the OR to help make these complex cases more manageable:

Viscoelastic

This gel can be used to help shield the corneal endothelium from excess ultrasound energy and prevent wound burns.5-7 It can also be used to viscodissect the lens nucleus in cases of posterior polar cataract, and push back vitreous from presenting in the case of a posterior capsular tear.5-10

Anterior vitrectomy

This may be needed in case of posterior capsular rupture, or zonular loss.1,7,11,12 Presence of vitreous can make cataract surgery difficult and removal of nuclear pieces inefficient (and in some cases impossible). In addition, a vitrector should be used to cut vitreous, as an aspiration probe can induce vitreous traction, and subsequent risk of retinal tear and detachment.1,7,11,12

Trypan blue

This dye aids in improving visualization of the anterior capsule during cataract surgery—especially those with a decreased red reflex (very dense or white cataracts as well as eyes with retinal disease).1,13,14

30-Gauge needle on an air syringe

This may be helpful to decompress an intumescent cataract prior to capsulorhexis creation to avoid anterior capsular run-out.14

Triamcinolone intraocular steroid

This can be injected into the anterior chamber during anterior vitrectomy, or used to determine if there is presence of vitreous, as it stains the vitreous white.11 This highlights the areas where vitreous is presenting, which can be especially helpful to identify if going to a wound, or causing tilt or a shift in an IOL.11

Capsular tension hooks

The presence of zonular weakness increases the risk of intraoperative complications and therefore capsular support devices are important management tools for eyes with zonulopathy.15-18 They facilitate safe and successful cataract surgery by improving capsular bag stability and centration.

Capsular tension rings/segments

Capsular tension rings and segments increase the chance of capsular bag placement of an intraocular lens (IOL).1,15-18 Rings and segments exert an outward force that redistributes tension from areas of intact zonules to strengthen areas of weak or missing zonules. 1,7,15-18 A standard capsular tension ring may not be adequate for eyes with advanced zonular weakness—eyes with >4 clock hours of zonular loss or progressive zonulopathy may require endocapsular segments that can be scleral-fixated.1,7,15-18

Pupillary expansion devices

Non-dilating or poorly dilating pupils pose challenges during cataract surgery due to reduced surgical space, small capsulorhexis, difficulty maneuvering the lens during surgery as well as risk of anterior or posterior capsular tear.1,15,17 When pharmaceutical dilation is not adequate, mechanical dilation of the pupil may be employed using iris hooks or pupil expansion rings (e.g., Hydroview Iris Protector Ring (Grieshaber &Co, AG Schaffhausen, Schaffhausen, Switzerland, Seipser iDeal iris ring (Eagle Vision, Memphis Tennessee USA), Malyugin Ring (Microsurgical Technology/MST Inc, Redmond, Washington USA)).1,15,17

Back-up IOLs

In cases of posterior capsular rupture or unstable zonules, it may not be possible to insert a single-piece IOL in the capsular bag.1-5 When this occurs, it is important to have back-up IOL’s on hand, including 3-piece IOL’s that can be placed in the ciliary sulcus, sutured to the iris, or scleral fixated as well as anterior chamber IOLs (ACIOL), if necessary.

Common patient risk factors for complex cataract surgery

Pseudoexfoliation syndrome

Pseudoexfoliation syndrome (PEX) is a systemic syndrome that targets mainly ocular tissues though gradual deposition of fibrillary white, flaky material onto the lens capsule, ciliary body, zonules, corneal endothelium, iris and pupillary margin—these deposits may also been found elsewhere in the body, including skin, heart, lungs, liver, and kidneys.1,10,12 PEX may be bilateral and asymmetric; it is more prevalent in older age (<70 years old) and those of Scandinavian descent.1,10,12

Precautions must be taken here during cataract surgery due to possible zonular instability, loss or dialysis, poor pupillary dilation, and phacodonesis.1,10,12 Therefore, these patients may be at higher risk of intraoperative complications and will require specific instrumentation available in the OR, should cataract surgery become complex and require capsular support, anterior vitrectomy, or use of a 3-piece or ACIOL.

Figure 1 demonstrates a dislocated IOL due to advanced pseudoexfoliation.

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Figure 1. Photo courtesy of Eric Rosenberg, DO MSE

Blunt ocular trauma

Trauma can affect the lens in several ways; it may result in subluxation or dislocation.1,2,7 Traumatic cataracts can also be intumescent in nature, but their type and clinical course depend on the trauma mechanism and capsular bag integrity.1,2,7 If the anterior capsule is not intact, microscissors may be used to create a controlled rhexis—trypan blue is also helpful here to aid in visualization.1,2,7,13 Zonulopathy and zonular weakness may also be present, therefore, care must be taken to be gentle with the capsule; capsular support devices may be required.

Figure 2 shows a traumatic cataract with iridodialysis.

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Figure 2. Photo courtesy of Eric Rosenberg, DO MSE

Penetrating ocular trauma

In the cases of acute traumatic cataract due to penetrating trauma, care must be directed towards stabilizing and closing the globe.1,2,7,13 Other penetrating and external ocular injuries must be ruled out and addressed. Ensuring the patient is stable prior to surgery is necessary as well. Closure of all open globe injuries should be prioritized first; cataract removal may need to wait until the globe is stabilized in order to prevent inadvertent damage to internal ocular structures.

In addition, a lacerated or traumatized globe compromises IOL calculations—if the surgeon wishes to emergently place an IOL at the time of globe repair, they may base calculations on the opposite eye’s measurements.1,2,7,13 It should be made clear to the patient that IOL calculations here are an estimate, and primary focus is on repair and reconstruction of the globe–as well as saving vision.1,2,7,13

Figure 3 demonstrates an eye post-repair of penetrating trauma with a subluxated crystalline lens.

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Figure 3. Photo courtesy of Eric Rosenberg, DO MSE

Zonulopathy

Loose or missing zonules may be a result of prior trauma, coloboma, and pseudoexfoliation.1,2,4,5,7,10,18,19 Sometimes, tapping the slit lamp at time of preoperative exam can demonstrate phacodonesis.1,2,4,5,7,10,18,19 Examining the patient lying flat may also show a tilting of the crystalline lens; occult zonular loss may be visible with good dilation.1,2,4,5,7,10,18,19 In these cases, the surgeon should be prepared to perform anterior vitrectomy, use capsular support devices (hooks, rings, segments, if necessary), and inform the patient that it may not be possible to place an IOL at time of surgery if removal of the cataract is especially difficult. 1,2,4,5,7,10,18,19

Figure 4 demonstrates a subluxated crystalline lens due to zonulopathy from Marfans syndrome.

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Figure 4. Photo courtesy of Eric Rosenberg, DO MSE

Lens abnormalities (spherophakia, coloboma, posterior polar cataract)

Cataract surgery in patients with lenticular abnormalities can pose specific concerns, especially for zonulopathy and difficult cataract removal. 1,2,4,5,7,10,18,19 Specifically, these entities may include, spherophakia, coloboma, and Marfan’s syndrome.1,2,4,5,7,10,18,19 I treat all of these patients as complex cases, as they are at high risk (or guaranteed risk) of zonular loss/weakness, requiring capsular tension support devices.

These patients need to be informed that due to abnormal anatomy, IOL placement at time of initial cataract surgery may not be possible; and that further surgery, including vitrectomy, may be required.1,2,4,5,7,10,18,19 In general, these eyes must be handled with great caution due to the increased risk of retinal detachment, and association of maculopathy.1,2,4,5,7,10,18,19

Figure 5 demonstrates a lens with microspherophakia that has dislocated into the anterior chamber.

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Figure 5. Photo courtesy of Eric Rosenberg, DO MSE

Figure 6 demonstrates an eye with coloboma of the iris and lens.