What laboratory tests are required before undergoing cataract surgery?

Laboratory Testing Before Cataract Surgery

Patients in their usual state of health undergoing cataract surgery do not require any routine preoperative laboratory testing. 1, 2, 3

Evidence-Based Recommendation

The evidence is unequivocal and robust on this topic:

• No routine labs are indicated for healthy patients undergoing cataract surgery, based on Level A evidence (consistent, good-quality patient-oriented evidence). 1

• Three large randomized controlled trials involving over 21,000 cataract surgeries demonstrated that routine preoperative medical testing does not reduce intraoperative or postoperative medical complications. 3, 4, 5

• The landmark Study of Medical Testing for Cataract Surgery (19,557 operations) found identical complication rates (31.3 events per 1000 operations) whether or not patients underwent routine testing with ECG, complete blood count, and metabolic panels. 4

When Directed Testing May Be Appropriate

While routine testing is not indicated, directed testing should only be obtained for specific clinical conditions that would actually change perioperative management: 2, 3

Specific Scenarios Requiring Testing:

• Hemoglobin/CBC: Only if the patient has known anemia, symptoms suggesting anemia, or is over 75 years old undergoing major surgery with general anesthesia (not typical for cataract surgery). 3

• Renal function (eGFR/creatinine): Only if the patient has known kidney disease or takes medications requiring renal dose adjustment. 3

• Glucose/HbA1c: Only if the patient has poorly controlled diabetes requiring perioperative management adjustment. 1, 2

• Coagulation studies: Only for patients taking anticoagulants, with bleeding history, or conditions predisposing to coagulopathy (e.g., liver disease). 1

• ECG: Only for patients with active cardiovascular signs or symptoms. 1

High-Risk Patients Requiring Medical Evaluation

Preoperative medical evaluation by the primary care physician (not laboratory testing) should be considered for: 2

• Chronic obstructive pulmonary disease
• Poorly controlled hypertension
• Recent myocardial infarction or unstable angina
• Poorly controlled congestive heart failure
• Poorly controlled diabetes

Essential Ophthalmic-Specific Evaluations

The following are ophthalmic assessments (not laboratory tests) that are necessary: 1, 2

• Optical biometry for intraocular lens power calculation (recommended over ultrasound techniques). 2
• Dry eye disease screening, as visually significant dry eye may require treatment before surgery. 1, 2
• Assessment for blepharoptosis, which can affect corneal astigmatism measurements. 2

Cost and Safety Considerations

• Routine preoperative testing adds 2.55 times higher costs without any safety benefit. 5
• Most cataract surgery is performed with topical anesthesia, eliminating the need for systemic medical clearance that would be required for general anesthesia. 6
• Anticoagulants do not need to be discontinued for cataract surgery. 6

Common Pitfalls to Avoid

• Do not order routine labs "just to be safe" – this adds cost and patient burden without improving outcomes. 7, 5
• Do not require a general medical history and physical for all patients – the operating ophthalmologist's assessment is sufficient for most patients. 2, 7
• Do not delay surgery for minor laboratory abnormalities that would not change perioperative management. 2