Lisette Scheer is an Optometrist and Low Vision Director at Viera VA Outpatient Clinic in Melbourne, Florida. Susannah Marcus- Freeman is an Optometrist at Malcom Randall VA Medical Center in Gainesville, Florida. Correspondence: Lisette Scheer (lisette.scheer@va.gov)
Author disclosures The authors report no actual or potential conflicts of interest with regard to this article.
Disclaimer The opinions expressed herein are those of the authors and do not necessarily reflect those of Federal Practitioner, Frontline Medical Communications Inc., the US Government, or any of its agencies. This article may discuss unlabeled or investigational use of certain drugs. Please review the complete prescribing information for specific drugs or drug combinations—including indications, contraindications, warnings, and adverse effects—before administering pharmacologic therapy to patients.
In July 1967, Charles Kelman, MD, suggested using a dental ultrasonic tool, normally employed to clean teeth, to fragment the nucleus of the crystalline lens. Dr. Kelman’s first operation using phacoemulsification on a human eye took 3 hours.7 As the procedure for cataract removal has been refined, complication rates and surgical times have vastly improved.
Phacoemulsification is the most commonly performed outpatient surgery in the US; about 3 million cases are performed annually. Due to the high volume of cases, adverse events (AEs) are not uncommon. The incidence of complications following phacoemulsification is < 5%; the frequency of severe complications has been estimated at < 0.7%.8 Severe complications include endophthalmitis, suprachoroidal hemorrhage, and/or retinal detachment.9 Studies have shown a decline in rates of sight-threatening AEs from 1994 to 2006.9 A retrospective study of 45,082 veterans from 2005 to 2007 identified that a preoperative disease burden such as diabetes mellitus, chronic pulmonary disease, age-related macular degeneration, and diabetes with ophthalmic manifestations, was positively associated with a greater risk of cataract surgical complications.10
Complications
The level of a surgeon’s proficiency with phacoemulsification is directly correlated to the number of operations performed; there is a lower complication rate among more experienced surgeons, including those who work in high-volume settings.11,12 One study identified that the AE rate within 14 days of surgery was 0.8% for surgeons performing 50 to 250 cataract surgeries per year, but only 0.1% for those performing > 1000 cataract surgeries annually.12
Potential postoperative lens exchange complications include increased IOP, corneal wound leakage, corneal edema, bullous keratopathy, cystoid macular edema, retinal detachment, and endophthalmitis (Table 1). A corneal wound leak can provide a potential ingress for bacteria, putting the patient at risk for endophthalmitis, perhaps the most devastating complication following cataract surgery.
Endophthalmitis
Endophthalmitis has been reported to occur in .001% to .327% of patients during postoperative care.5,13-17 Early detection is important to maintain corneal integrity and prevent a cascade of detrimental ocular sequalae including the potential for endophthalmitis. According to Zaida and colleagues, endophthalmitis occurred in fewer than 1 of 1000 consecutive cases.14 A leaking clear corneal incision wound on the first day postoperatively has been associated with a 44-fold increased risk of endophthalmitis.13
Causes of endophthalmitis
In a retrospective case-controlled series of 57 patients with postcataract endophthalmitis, implantation of an intraocular lens with a resultant wound abnormality was thought to be the causative factor in 5%.17 Another source of endophthalmitis can be the intraocular lens (IOL), which may act as a vector for bacteria. By placing the IOL against the conjunctiva or exposing it to the theater air during surgery, bacteria can be introduced prior to implantation.17 Immunosuppressive treatment is the only patient antecedent factor that can be considered a predictor for endopthalmitis.17
The internal corneal seal is IOP dependent, and postoperative ocular hypotony may cause a seemingly watertight wound to leak. Taban and colleagues used anterior segment OCT to image numerous self-sealing incisions. They found that the corneal incision wound more tightly seals at higher IOPs. Additionally, more perpendicular (larger angle) incisions seal better at a lower IOP while less perpendicular (smaller angle) incisions seal better at a higher IOP (Figure 6).18
