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Schein OD, Katz J, Bass EB, Tielsch JM, Lubomski LH, Feldman MA, Petty BG, Steinberg EP. The value of routine preoperative medical testing before cataract surgery. Study of Medical Testing for Cataract Surgery. The New England journal of medicine. 2000;342:168-75. PMID 10639542

One-paragraph summary

The Study of Medical Testing for Cataract Surgery randomly assigned 19,557 elective cataract operations in 18,189 patients at nine centres to be preceded, or not preceded, by a standard battery of medical tests — electrocardiography, complete blood count, and serum electrolytes, urea nitrogen, creatinine and glucose — in addition to history and physical examination. Adverse medical events and interventions on the day of surgery and during the following seven days were recorded. Medical outcomes were assessed in 9,408 patients undergoing 9,626 operations without routine testing and 9,411 patients undergoing 9,624 operations with it. The most frequent events in both groups were treatment for hypertension and for arrhythmia, principally bradycardia. The overall complication rate was identical at 31.3 events per 1,000 operations in both arms, with intraoperative rates of 19.2 and 19.7 per 1,000 respectively and no significant difference in postoperative events.

Key findings

  • Overall complication rate: 31.3 per 1,000 operations in both arms — identical.
  • Intraoperative events: 19.2 (no testing) vs 19.7 (testing) per 1,000.
  • Commonest events in both groups: treatment for hypertension and for bradycardia.
  • Nearly 20,000 randomised operations — one of the largest randomised trials in ophthalmology.

Limitations

  • Elective cataract surgery under local anaesthesia; the result does not generalise to other surgery or to patients requiring general anaesthesia for other reasons.
  • Tests a battery, not selective testing indicated by history — the comparator in the Cochrane review is "selective or no testing" (Keay 2019, PMID 30616299).
  • Cannot exclude benefit in very small high-risk subgroups, though the event rate leaves little room for one.
  • 1990s testing practice and 1990s anaesthetic technique.

Why it matters

This trial, together with two smaller randomised studies, became the evidence base for one of ophthalmology's few successful de-implementation campaigns. The Cochrane review pooling all three (21,531 operations) found 353 medical adverse events in the tested group and 354 in the untested group (OR 1.00, 95% CI 0.86–1.16, high certainty), no reduction in intraoperative (OR 0.99, 0.71–1.38) or postoperative ocular events (1.11, 0.74–1.67), no difference in cancellations (0.97, 0.78–1.21), and costs 2.55 times higher with routine testing (PMID 30616299). Guideline synthesis now identifies "avoid routine preoperative medical tests for surgery under local anaesthesia" as one of only two recommendations on which high-quality cataract guidelines widely agree (García Anguas 2025, PMID 41027307), and observational work has shown that ophthalmologist-led pathways without dedicated anaesthesia support are safe (Koolwijk 2015, PMID 25444350). The gap between publication and practice change — measured in decades — is itself a case study in implementation (Schein 2021, PMID 33485473).

Cited by wiki pages

  • diagnosis-and-preoperative-assessment
  • anaesthesia-and-perioperative-care
  • guidelines
  • clinical-trials-landscape