Are laboratory tests required before undergoing eye surgery?

Laboratory Tests Are Not Required Before Eye Surgery

Routine preoperative laboratory tests are not required before eye surgery, particularly cataract surgery, as they do not reduce perioperative morbidity or mortality. 1, 2, 3, 4

Evidence Against Routine Preoperative Testing

• A large randomized controlled trial involving over 19,000 cataract surgeries demonstrated that routine preoperative medical testing (including complete blood count, electrolytes, creatinine, and glucose) did not increase surgical safety compared to no testing 3
• This finding was reinforced by a 2012 Cochrane review that analyzed 21,531 cataract surgeries and found no reduction in adverse events with preoperative testing 4
• The American Academy of Ophthalmology explicitly states that no routine preoperative laboratory testing is required for most patients undergoing cataract surgery 2

When Testing May Be Considered

While routine testing is not required, targeted testing may be appropriate in specific circumstances:

Specific Patient Populations

• Patients with severe systemic diseases such as:
  • Poorly controlled diabetes
  • Unstable cardiovascular disease
  • Chronic kidney disease stage 3a or worse
  • Recent myocardial infarction
  • Unstable angina
  • Poorly controlled congestive heart failure 2

Specific Tests to Consider in High-Risk Patients

1. Coagulation testing: Only for patients with:

   • History of bleeding disorders
   • Medical conditions affecting hemostasis (liver disease, hematopoietic disorders)
   • Current anticoagulant therapy
   • History suggesting coagulation disorder 1

2. Complete blood count: Only for patients with:

   • Known anemia
   • Conditions increasing risk of anemia
   • Anticipated significant perioperative blood loss 1

3. Electrolyte and creatinine testing: Only for patients with:

   • Chronic kidney disease
   • Medications predisposing to electrolyte abnormalities 1, 2

4. Glucose testing: Only for patients at high risk of undiagnosed diabetes or if results would change perioperative management 1

Important Caveats

• Continuing antiplatelet or anticoagulant medications during ophthalmic surgery is generally safer than discontinuing them, as the risk of thromboembolic events outweighs the risk of significant ocular hemorrhage 5
• The cost of routine preoperative testing is estimated to be 2.55 times higher than selective testing with no improvement in outcomes 4
• A 2023 systematic review of 48,869 eyes confirmed that routine preoperative testing does not decrease the incidence of adverse events or perioperative complications 6

Conclusion

The evidence strongly supports that routine laboratory testing before eye surgery, particularly cataract surgery, is unnecessary and does not improve patient outcomes. Testing should be limited to specific situations where results would alter perioperative management based on a patient's medical history and risk factors.