Cataract Surgery Complications
Complications of Cataract Surgery
Cataract surgery dates back to the 1700s. With new advancements in technology, infectious disease control, and equipment, there are fewer postoperative adverse events following the procedure. However, complications still do occur both intra and post-operatively. The current goal of cataract surgery is to remove the cataract and replace it with an intraocular lens, which is typically placed in the capsular bag of the posterior chamber.
As with any surgical procedure there are risks associated with operation and the post-operative state. Listed below are general factors that increase the risk of complications with cataract surgery.
Risk factors associated with worse visual outcomes
- Age-related macular degeneration
- Diabetic retinopathy
- Corneal opacity/pathology
- Older age
- Female sex
- Previous vitrectomy
- Previous retinal detachment
- Alpha blockade
- Intraoperative complications
Complications can range from immediate to delayed complications following the procedure. Some immediate complications are a result of having the surgical procedure. These include discomfort, bruising and swelling of the eyelid, increased intraocular pressure, and allergic reaction to the steroid or antibiotic drop. These complications are monitored over time following surgery. If there is progression to pain, decrease in vision, or any discharge from the eye, patients are advised to seek medical attention.
A long-term consequence of cataract surgery is posterior capsular opacification (PCO). PCO is the most common complication of cataract surgery. PCO can begin to form at any point following cataract surgery. Modern cataract surgery creates a capsular bag that contains part of the anterior, the entire posterior capsule, and the implanted, intraocular lens. In the remaining anterior capsule, epithelial cells remain despite the surgical trauma. These epithelial cells will begin to settle on the anterior capsule and colonize the posterior capsule. The cells will continue to divide and begin to alter the lens matrix and therefore the refraction of the lens. PCO can successfully be treated with YAG laser capsulotomy, which will provide almost immediate improvement in vision.
Complications discussed below can be immediate complications but are more severe than those previously mentioned.
Due to the nature of cataract surgery, posterior capsule tears may occur at any point during the operation. The capsulotomy step of the surgery is the most crucial, not only to create an opening to access the nucleus of the lens, but also due to the associated high risks if improperly performed. Loss of the vitreous due to capsular rupture can lead to severe visual disability and other complications previously mentioned such as retinal detachment. Risk factors that contribute to increased likelihood of vitreous loss include deep-set eyes, narrow palpebral fissures, high myopia, glaucoma, previous pars plana vitrectomy and a previous history of vitreous loss. Systemic risk factors include Marfan syndrome, morbid obesity, hypertension and diabetes. There are several intraoperative signs that suggest that the posterior capsule has been broken: deepening of the anterior chamber, absence of lens material that has not yet been removed, sudden appearance of an area of the posterior capsule that appears "too clear," vitreous in the phaco or aspiration tip, or movement of the lens away from the phaco tip. Rupture of the posterior capsule can lead to other secondary complications of cataract surgery. Early recognition is vital to preventing further damage. Secondary complications can include: cystoid macular edema, retinal tears/detachment, glaucoma, corneal decompensation, endophthalmitis, retained lens material, prolonged postoperative inflammation, prolonged case time, and patient discomfort.
Cystoid Macular Edema
CME is the most frequent complication after an uncomplicated cataract surgery. Its peak incidence is about 6 to 8 weeks post-operatively. Optical coherence tomography (OCT) is the standard method for diagnosis and monitoring of CME, though fluorescein angiography is considered the gold standard. With modern phacoemulsification techniques, CME occurs in about 1 to 2% of cataract surgery. It results from an increased permeability of perifoveal capillaries and disruption of the blood-ocular barrier, allowing for the formation of cystoid spaces in the Henle’s and outer plexiform layers to absorb and hold fluid. Fluid collection places mechanical stress on the Muller cells, which manifest as decreased central vision and scotoma in the patient.
Endophthalmitis is a serious complication of cataract surgery involving microorganisms that gain entry into the eye. Risk factors for the development of endophthalmitis include rupture of the posterior capsule or the need for anterior vitrectomy during the procedure, age greater than 85 years, and male sex. Higher rates of endophthalmitis were found in patients undergoing intracapsular cataract extraction compared to extracapsular cataract extraction. Staphylococcus epidermidis is the most common infectious organism since it is native to the eyelid, skin, and conjunctiva and can seed the eye during the procedure.
Hemorrhage is a sight-threatening complication that is often associated with incisional intraocular surgery. Risk factors determined for hemorrhage include myopia, glaucoma, diabetes, atherosclerotic vascular disease, and hypertension.
Retinal detachment is considered a delayed complication of cataract surgery. Those with highly myopic eyes or a history of retinopathy of premature and develop early cataracts are at an increased risk of retinal detachment following surgery. Retinal detachment risk is also increased in patients who have received YAG laser capsulotomy following surgery and development of PCO.
Though rare, IOL dislocation is another principal complication following cataract surgery. Improvements in the foldable IOL design has decreased the incidence of postoperative dislocation. Inadequate capsular support is the main cause of lens dislocation and typically occurs early in the postoperative period. However, late, “in-the-bag” dislocations can occur from progressive zonular dehiscence many months after uncomplicated surgery. Management involves IOL repositioning with or without scleral fixation sutures, or replacement with an anterior chamber IOL.
Management of the complications follow the medical guidelines for the management of the injury/illnesses listed above in the setting without cataract surgery involvement. The main area of management is in prevention of complications. However, in the setting of a ruptured posterior capsule, surgical measures are taken to not only complete the case, but also minimize trauma to the retina. An anterior vitrectomy may be required to manage vitreous prolapse while preserving the remaining capsule for lens implant. Assistance from a retina specialist may be required. A posterior capsule intraocular lens may no longer be feasible for the patient, but other options include a capsule-supported sulcus IOL, anterior chamber IOL, or an iris or scleral sutured sulcus IOL. New research has also looked into the prevention of endophthalmitis with an injection of cefuroxamine following a cataract procedure. New technology continues to innovate surgical procedure that can further safety and prevention measures for surgery complications.
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