Fluid misdirection can cause challenges during cataract surgery
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Compared with methods of manual cataract extraction, phacoemulsification offers so many benefits such as a smaller incision, a higher margin of safety and a faster recovery of vision for our patients.
We accomplish this lens emulsification by operating within a relatively closed anterior segment where an infusion of balanced salt solution is used to maintain chamber stability. This flow of balanced salt solution allows the lens fragments to be brought to the phaco tip where they can be aspirated. However, there are also cases in which this fluid can be misdirected and cause challenges with the cataract surgery.
Source: Uday Devgan, MD
The fluid volume of the anterior chamber is about 0.25 cc, and the posterior chamber is about the same, depending on how much lens material remains in the capsular bag. If a surgeon uses 100 cc of balanced salt solution during the cataract surgery, then the anterior segment of the eye may be turned over 200 times. This coupled with the infusion pressure can push fluid through the zonular support fibers and into Berger’s space. This potential space between the back surface of the posterior capsule and the anterior hyaloid face can accumulate balanced salt solution and also some tiny lens fragments.
With reasonable strength of the zonular support fibers, only tiny lens fragments tend to get pushed into this space with just a small amount of fluid. These fragments are relatively commonly seen (Figure 1) and dissolve in the cascade of inflammation in the postop period. The standard postop regimen of topical corticosteroids and other anti-inflammatory medications is sufficient to aid in patient healing.
In cataract cases with significant zonulopathy, we can see larger lens fragments become trapped in Berger’s space with significant accumulation of balanced salt solution. This additional volume of fluid in front of the anterior hyaloid face will push the posterior lens capsule forward. Because the posterior capsule is often challenging to visualize, an attempt to aspirate these lens fragments with the irrigation-aspiration probe will simply result in capsular striae (Figure 2). Surgeons may also note a shallow capsular bag and more of a challenge removing cortex from the lens equator.
If there is an area of focal zonular loss that is noted, which is often due to prior trauma, placement of a capsular tension ring can help to stabilize the capsular bag and limit further misdirection of balanced salt solution. Prior to placing the capsular tension ring, a cohesive viscoelastic can be injected into the capsular bag to inflate it and also help push out some of the accumulated balanced salt solution from Berger’s space. Once the IOL has been placed, the surgeon should also look for evidence of vitreous prolapse through the area of zonular loss.
For patients with generalized zonular laxity instead of focal loss due to conditions such as pseudoexfoliation or advanced age, a capsular tension ring may not be absolutely needed. While it can help stabilize the capsular bag equator, it will not do anything to prevent progressive zonulopathy in the future.
For large lens fragments that are retained in the vitreous cavity, such as when there is a posterior capsule rupture with posterior displacement of nuclear material, a vitrectomy is usually advised in order to remove them. This is typically performed via the pars plana, and it may require complete removal of all vitreous from the eye. For an intact posterior capsule and a few lens cortical fragments in Berger’s space, a reasonable approach is to allow time for them to dissolve in the cascade of inflammation during the postoperative period. Doing an immediate vitrectomy to access these pieces is usually not needed.
Injecting preservative-free triamcinolone (Figure 3) can also help to quell the postop inflammation that may be induced by these retained lens fragments. A dose of 0.5 mg to 1 mg can be administered via a 27-gauge blunt cannula into the anterior chamber at the end of the surgery. Should further triamcinolone be needed, larger doses can also be placed directly into the vitreous cavity or in depot form in the sub-Tenon’s space.
In the postoperative period, these patients tend to do well, and the lens fragments are gone within a few weeks. While the anterior placement of triamcinolone will only last a few days, injection of depot doses will last longer and could induce issues such as increased IOP, which then needs to be treated and monitored. Patients with fluid misdirection syndrome during cataract surgery can pose additional challenges that we can fortunately overcome to produce an excellent visual outcome.
For a video of this case, please visit https://cataractcoach.com/?s=misdirection.
- For more information:
- Uday Devgan, MD, in private practice at Devgan Eye Surgery and a partner at Specialty Surgical Center in Beverly Hills, California, can be reached at devgan@gmail.com; website: www.CataractCoach.com.
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