Almost 15% of medical malpractice claims in ophthalmology involve retained lens fragments. Most of these claims name the cataract surgeon as defendant. Only a small minority claim the retinal surgeon as defendant. Cases analyzed by an expert witness is needed to determine the presence or absence of negligence, the significance of any injuries, and the costs of future care and treatment.
During modern cataract surgery, the opacified lens of the eye is broken into small pieces by an ultrasound method known as phacoemulsification. The lens is enclosed within a capsule much like an orange within a peel. In cataract surgery a porthole opening is created in the capsule and emulsification is performed within the contents of the capsule.
The capsule is very thin and prone to breakage. The capsule is about 4 microns thick and the human hair is about 80 micros thick. If the capsule breaks before the cataract is removed, small chunks of the cataract can drift through the opening of the broken capsule and migrate toward the back of the eye. Cataract fragments can become situated in the vitreous jelly or travel to the back of the eye and rest on the surface of the retina. In certain cases, fragments of the cataract may remain in the anterior portion of the eye. Cataract fragments that have migrated to the back of the eye are generally treated by a retinal surgeon. Therefore, a cataract surgery complicated by lens fragments that are left in the eye is referred to as a case with retained lens fragments.
In certain conditions of the eye, there is an increased risk of capsular rupture. These conditions include pre-existing trauma with damage to the tissue (zonules) that hold the capsule in place, pseudoexfoliation, floppy iris syndrome, unexpected patient movement during surgery, highly advanced cataract, and high myopia.
Retained lens fragments can result in a number of secondary complications that can cause damage to the eye and loss of vision. Some of the major complications may be summarized as follows:
1) Elevated intraocular pressure: The presence of remaining cataract material can result in an inflammatory response. The inflammatory cells clog up the drainage pores of the eye. As a result, the fluid that normally circulates out of the eye through these pores build up within the eye to cause elevated pressure. Inflammation of the eye is usually treated with steroid-based medications. Medications with steroids, especially if used for a prolonged period of time, can cause pressure elevation. Elevated pressure that causes damage to the optic nerve is known as glaucoma.
2) Scar tissue: The inflammatory response to retained cataract fragments can also cause adhesions to form. These adhesions are composed of scar tissue that can cause direct damage the retina or cause the retina to detach.
3) Corneal edema: Inflammation inside the eye can damage endothelial cells that line the internal portion of the cornea. Damage to the endothelial cells can result in edema or swelling of the cornea. Swelling of the cornea causes it to become hazy. Fortunately, corneal swelling resolves over time after the inflammation abates. However, corneal edema may persist if inflammation is not controlled or if there is irreversible damage to the endothelial lining of the cornea.
Malpractice in cataract surgery related to retained lens fragments is often dependent on the circumstances for this complication. The manner in which it was treated and the timing of referral and treatment, are important considerations. Expert ophthalmology evaluation and testimony is often needed to analyze issues of liability in cases of complicated cataract surgery.
1. Kim, JE, Weber, JD, and Szabo, A. Medical Malpractice Claims Related to Cataract Surgery Complicated by Retained Lens Fragments (An American Ophthalmological Society Thesis). Trans Am Ophthalmol Soc. 2012 December; 110: 94–116.
2. Schwartz SG, Holz ER, Mieler WF, Kuhl DP. Retained lens fragments in resident-performed cataract extractions. CLAO J. 2002;28(1):44–47.
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