The first reported surgical removal of a cataract from the eye occurred in Paris in 1748.
Since that time, the evolution of cataract extraction has reached a point that was unfathomable to surgeons as little as a decade ago.
For example, the CATALYS® Precision Laser System allows for anterior capsulotomy, phacofragmentation, and the creation of a single plane and multi-plane arc cuts/incisions in the cornea, each of which may be performed either individually or consecutively during the same procedure.
Even with all the technological advancements, cataract removal is still a surgical procedure performed by humans, which means at some point, there will inherently be complications.
Today, we will cover the most common complications that you will likely see in your office, and how to effectively manage them.
The most common complication that you will see in your office following cataract extraction is elevated intraocular pressure.
Fortunately, most cases are mild and self-limiting. Two of the most likely causes are retention of viscoelastic substances and obstruction of the trabecular meshwork with inflammatory debris. Something to keep in mind is that patients who have pre-existing glaucoma are at much greater risk of developing acute significant pressure elevation.
A typical rule of thumb is that a patient with mild pressure elevation (IOP in the 20s) is treated topically with a beta blocker, alpha agonist, or carbonic anhydrase inhibitor (depending on the individual), while those with an IOP over 30mmHg need to be “burped” or “vented.”
This procedure is very straight forward, but can be daunting for those who have not performed it recently, or at all.
- The first step is to instill anesthetic and antibiotic, and locate the paracentesis.
- This incision is usually located about two clock hours from the main corneal incision.
- Next, use a blunt tipped probe to depress the posterior lip of the incision, which allows a small amount of viscoelastic and aqueous to escape. One small drop of the fluid escaping roughly equals a 10mmHg reduction.
- Repeat this procedure as necessary until the IOP is brought into the low to normal range.
- Measure the patient’s pressure and then re-check in 15-20 minutes to make sure it has stayed down.
Some optional adjunctive treatments would be to start the patient on acetazolamide (if there is no sulfa allergy), 250 mg, q.i.d., for a day or two to help keep the pressure down and to double up on the antibiotic drops, even though I have never seen an infection caused by this procedure. Since we are not cutting or inserting anything into the eye, this procedure is in the scope of practice of every optometrist, however, it is advisable to communicate with your surgeon first and establish standing orders or protocols when the situation occurs.
Another common complication that we see in the days following cataract surgery is corneal edema.
The innermost layer of the cornea is made up of endothelial cells. These cells form a physical barrier between the corneal stroma and aqueous humor and acts as an ion pump to maintain the correct level of corneal hydration.
Factors that predispose to corneal edema following cataract surgery include the following:
- intraoperative mechanical endothelial trauma
- prior endothelial disease or cell loss
- excessive postoperative inflammation
- prolonged postoperative elevation of IOP
Preoperatively patients should be carefully examined for evidence of Fuchs’ dystrophy or other conditions that produce a low endothelial cell count.
Even a flawless cataract extraction will damage some of the endothelial cells. Fortunately, we have a reserve of these cells, so a small loss will rarely manifest problems. However, on occasion there may be injury to a significant number of cells, resulting in a decrease of endothelial cell density. This can impair the ability of the endothelium to maintain corneal clarity, resulting in corneal edema and discomfort.
Topical corticosteroids are the treatment of choice for corneal edema and inflammation, with special attention being paid to the patient’s IOP.
Keeping the IOP below 20 mmHg is important for reducing the corneal edema because increased IOP can lead to epithelial edema, causing further endothelial damage. If the IOP is raised, the condition should be treated with topical and/or systemic antiglaucoma medication.
Epithelial edema can often be managed with topical hypertonic agents such as sodium chloride ointment or drops. Muro 128 5% ointment at night is particularly useful because the edema tends to be more severe on waking in the morning because of lack of evaporation during the night when the eyes are closed.
Finally, amniotic membrane in the form of a free graft protected by a bandage CTL or a ring-mounted contact lens (ProKera, BioTissue) can provide adjunctive benefits through intrinsic wound healing and growth factors, as well as anticollagenolytic and antimicrobial properties.
Sequential corneal pachymetry is a great way to document the resolution of the postoperative corneal edema, which may take up to 3 months. It is advisable to wait at least this long before recommending a surgical procedure, such as anterior stromal puncture or phototherapeutic keratectomy.
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Nourouzi et al., Am J Ophthalmol. 2006;142(4):671-673.
"How Do I Burp This Baby?" Ed. Paul C. Ajamian. Review of Optometry, 15 Dec. 2011. Web. 24 Mar. 2016.
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