Introduction

Cataract surgery is the most common operation performed in the Medicare population. It has been proven to be a highly effective and safe procedure, with significant improvement in visual function and quality of life. In the past, the traditional approach for patients scheduled for cataract surgery was a comprehensive medical evaluation, including laboratory testing. However, there has been uncertainty over the effectiveness of preoperative medical testing such as complete blood counts (CBC), serum electrolytes, and electrocardiograms (EKG), and variation found in patterns of medical testing across the country. A survey reported that a significant proportion of the physicians did not believe that the tests were clinically necessary, but ordered them anyway due to institutional requirements, medicolegal concerns, or because they believed that another specialist wanted them performed.1 The direct cost to Medicare for routine medical testing prior to cataract surgery is estimated at $150 million each year.2

Background

In 1994, the Agency for Health Policy and Research initiated the Study of Medical Testing for Cataract Surgery.3 The purpose was to assess whether routine medical testing prior to cataract surgery reduces the rate of complications in the perioperative interval.

A large randomized controlled trial involved nine clinical centers, including private practices utilizing free-standing ambulatory surgery centers, community hospitals and academic medical centers. The study enrolled 18,189 patients scheduled to undergo 19,557 cataract surgeries, with 9,408 patients not receiving routine medical testing and 9,411 patients receiving routine testing. Follow-up data were 100% complete for the day of surgery and 99.8% complete for one week after surgery. The two groups of patients studied were comparable in age, sex, race, coexisting illnesses, American Society of Anesthesiology (ASA) risk class and self-reported health status. This study excluded patients who were to receive general anesthesia, who had a myocardial infarction within the preceding three months, and who could not speak English or Spanish.

This study demonstrated that routine preoperative laboratory testing in patients scheduled to undergo cataract surgery is not necessary. A preoperative history and physical examination was performed, and patients were randomized to routine testing (CBC, EKG, electrolytes, blood urea nitrogen, creatinine and glucose) versus testing only if a finding on the history or physical would have lead to a lab test even without the planned cataract surgery. Patients in both groups did have a finger-stick blood sugar if they were diabetic.

The overall rate of medical complications following cataract surgery was low, and generally were not serious or life-threatening. Adverse events developed at the time of surgery or within seven days of surgery in about 3% of cases in each group. Patients who had undergone routine medical testing did not have fewer adverse events, even when stratifying patients by age, sex, race, physical status and medical history.

This large, randomized controlled and multi-center trial provides strong evidence that routine use of laboratory tests prior to cataract surgery is not necessary and does not lead to improved outcomes. Perioperative morbidity and mortality were not decreased by the use of routine medical testing. Financial resources saved by elimination of unnecessary routine tests could be used for other patient care needs.

Conclusion

Routine medical tests performed on patients before cataract surgery are unnecessary because they do not increase the safety of the procedure. Preoperative medical tests can be ordered when a finding on a history or physical examination indicates a need, even if surgery were not scheduled.

References

1. Bass EB, Steinberg EP, Luthra et al: Do ophthalmologists, anesthesiologists, and internists agree about preoperative testing in health patients undergoing cataract surgery? Arch Ophthalmol 1995; 113:1248-56.

2. Schein OD: Assessing what we do: the example of preoperative medical testing. Arch Ophthalmol 1996; 114:1129-31.

3. Schein OD, Katz J, Bass, EB et al: The value of routine preoperative medical testing before cataract surgery. NEJM 2000; 342:168-75.