BLOG: What are the odds of permanent vision loss because of cataract surgery?
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What are the odds of a really serious complication from cataract surgery, a complication that would permanently decrease vision?
Ninety-seven percent of all cataract surgeries proceed with no complications, and the vast majority of the remainder only entail a longer healing time with greater visits. Nevertheless, there are at least three known complications that can result in permanent loss of vision from cataract surgery.
Endophthalmitis, an infection within the eye
The most feared complication of cataract surgery is undoubtedly endophthalmitis, in which a pathogen proliferates within the eye. Endophthalmitis almost always results in dramatic and permanent damage to the eye. The topical antibiotics used by the patient after surgery do little to blunt this risk, as the pathogen is usually introduced into the eye during the surgery.
The damage to the eye does not necessarily occur due to the pathogen itself, but rather from the destructive effects of nonresident immune cells. When the pathogen triggers an inflammatory episode, powerful but destructive immune cells from outside the eye swarm to the infection, and it is their actions that cause most of the damage (Chen et al).
The risk is greatest in patients with weakened immune systems — those older than 85 years, with poorly controlled diabetes, a compromised immune system or poor hygiene — and with complicated surgeries, such as mature or pseudoexfoliative cataracts, intraoperative posterior capsular rupture or a wound leak.
Thankfully, the risk for endophthalmitis is low. Surgeons now leave a depot of antibiotic in the anterior chamber at the conclusion of every surgery; this practice has reduced the national rate of endophthalmitis to about one in 10,000, or 0.01% (Frilling et al).
Retinal detachment, a bigger risk for some than others
The most common complication that can permanently damage a patient’s vision after cataract surgery is retinal detachment. The risk for rhegmatogenous retinal detachment (RRD) after cataract surgery has been decreasing decade by decade, but the jostling of the surgery, and the subsequent forward movement of the vitreous into the space formerly occupied by the bulky cataract, introduce structural changes in the eye that increase the risk for RRD for years afterwards.
In the first 10 years after cataract surgery, the risk for RRD in a pseudophakic eye is approximately 40 per 10,000, or 0.4%, against a background risk in unoperated eyes of 0.10%, so that the average risk above background is 0.3% — a fourfold increase.
Unfortunately, this risk increases sharply with certain risk factors: Highly myopic eyes, defined as axial length greater than 26 mm, have double the risk of the normal population, and men also have double the risk. Patients undergoing surgery who are younger than 50 years have triple the risk of the general population, and the presence of lattice degeneration makes the risk a shocking 10 times higher.
These factors are to some extent cumulative, so that a young myopic man with lattice degeneration who undergoes cataract surgery should be regarded as being at very high risk indeed (Haug et al).
Suprachoroidal hemorrhage, an intraoperative emergency
Suprachoroidal hemorrhage (SCH) is a rare but devastating complication in which blood accumulates in the suprachoroidal space during intraocular surgery.
The mechanism is believed to be as follows: If IOP is allowed to drop too low, the vacuum effect pulls serous fluid from the choroid into the potential space of the suprachoroid. The short and long posterior ciliary vessels traverse this space and will be stretched; if they are fragile, they can rupture.
The ensuing hemorrhage will have the force of arterial blood and can be explosive, to the point of ejecting intraocular contents out through any surgical incisions. Most cases of SCH result in severe visual impairment or blindness, with vision ranging from counting fingers to no light perception (Ling et al).
The risk for SCH rises for patients with older age, longer axial length, higher preoperative IOP, use of anticoagulation, hypertension, diabetes and atherosclerotic disease. Fortunately, the risk for SCH during cataract surgery is low; a recent review concluded that the risk was approximately seven in 10,000, or 0.07% (Liu et al).
Adding up these risks produces a total risk of permanent vision loss from these three cataract surgery complications at roughly 48 per 10,000, or 0.48% — although this risk can be higher, even much higher, among those with significant risk factors.
References:
- Chen A, et al. Br J Opthalmol. 2024;doi:10.1136/bjo-2023-323865.
- Frilling E, et al. J Cataract Refract Surg. 2024;doi:10.1097/j.jcrs.0000000000001464.
- Haug S, et al. Curr Opin Ophthalmol. 2012;doi:10.1097/ICU.0b013e32834cd653.
- Ling R, et al. Br J Ophthalmol. 2004;doi:10.1136/bjo.2003.026179.
- Liu T, et al. Surv Ophthalmol. 2024;doi:10.1016/j.survophthal.2024.09.009.
For more information:
Oliver Kuhn-Wilken, OD, practices at Pacific Cataract and Laser Institute’s Tualatin Clinic in Oregon. He can be reached at Oliver.Wilken@pcli.com.
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