AUTHORS: Sweitzer, BobbieJean MD, FACP, SAMBA-F, FASA et al

Anesthesia & Analgesia: December 2021 – Volume 133 – Issue 6 – p 1431-1436

Cataract surgeries are among the most common procedures requiring anesthesia care. Cataracts are a common cause of blindness. Surgery remains the only effective treatment of cataracts. Patients are often elderly with comorbidities. Most cataracts can be treated using topical or regional anesthesia with minimum or no sedation. There is minimal risk of adverse outcomes. There is general consensus that cataract surgery is extremely low risk, and the benefits of sight restoration and preservation are enormous. We present the Society for Ambulatory Anesthesia (SAMBA) position statement for preoperative care for cataract surgery.

More than 20 million cataract extractions are done worldwide yearly. Visual impairment impacts quality of life; increases falls,1 hip fractures,2–4 car accidents,5–11 health care utilization,12–14 social isolation, dependency, and nursing home placements15; and is associated with cognitive impairment.16–18 It is also associated with higher mortality.19,20 Waiting more than 4 months to perform cataract surgery after it is clearly indicated is associated with increased complications.21

Ophthalmic patients are often elderly with comorbidities which constantly threaten well-being. Diseases such as diabetes, hypertension, obesity, smoking, and systemic steroid use increase the risk of cataracts.22 If a patient can lie in a position that allows the procedure, there are few conditions or test results that preclude cataract surgery.23 In spite of evidence debunking the utility of testing before cataract surgery, studies suggest that medical testing and the use of medical consultations before cataract surgery continue to increase.24,25 Similarly, it has been emphasized that before delaying cataract surgery, one must consider vision loss, increased rates of falls and hip fractures, and reduced quality of life with continued cataracts. Cataract procedures are typically done with topical local anesthetics and minimal or no sedation. Cataract surgery has minimal physiological stress, no blood loss, fluid shifts, or need to interrupt chronic medications. Cataract surgery patients have a 0.014% chance of dying, and it is unlikely that risk can be lowered.26 Nevertheless, suitability of American Society of Anesthesiologists physical status (ASA-PS) IV patients in a free-standing ambulatory surgery center (ASC) remains controversial.

In response to requests from members of the Society for Ambulatory Anesthesia (SAMBA), a position statement concerning the safe preoperative care of patients undergoing cataract surgery was developed. To ensure that the recommendations maintain patient safety and have clinical validity in an ambulatory setting, the balance between the benefits and risks of cataract surgery were considered. Other ophthalmologic procedures are beyond the scope of this article.

In approving this document, a similar process was used as previously created by the SAMBA Board of Directors.


Which comorbidities preclude safe anesthetic care for patients undergoing cataract surgery?

There are a few situations where cataract surgery should likely be delayed to allow optimization of comorbidities. These include:

  • Myocardial infarction (uncomplicated) within the previous 30 days, if complicated infarction within 60 days
  • Percutaneous coronary interventions without stenting within 14 days or with stents within 30 days27,28
  • Significant arrhythmias with hemodynamic compromise (eg, ventricular tachycardia, atrial fibrillation with rapid ventricular rates29)
  • Decompensated heart failure29
  • Acute serious pulmonary conditions (eg, active pneumonia, upper respiratory infection with active symptoms, pulmonary embolus in past 3 months)30
  • Acute or recent severe neurologic conditions (eg, altered mental status, stroke or transient ischemic attacks [TIA] within 3 months, uncontrolled epilepsy, increased intracranial pressure)31
  • Malignant hypertension defined as elevated blood pressures with acute end-organ damage in at least 3 different target organs, typically kidneys, brain, and heart.32 Symptoms and signs may include encephalopathy, stroke, TIA, chest pain, dyspnea, arrhythmias, electrocardiographic evidence of ischemia, heart failure, or acute kidney injury
  • Diabetic ketoacidosis or hyperosmolar hyperglycemic nonketotic syndrome

Does Hypertension Warrant Cancellation of Cataract Surgery?

Hypertension is common in this age group and several studies indicate many patients have elevated arterial blood pressures immediately before cataract surgery.33 Hypertension is one of the most common reasons for cataract surgery to be postponed.34 However, there is little evidence to support that hypertension increases adverse events in patients having cataract surgery.35,36 The Perioperative Quality Initiative (POQI), an international, multidisciplinary organization, recommends that elective surgery should not be cancelled based solely because of a preoperative blood pressure.37

The Association of Anaesthetists of Great Britain and Ireland and the British Hypertension Society have noted that blood pressures obtained on the day of surgery are not reflective of baseline or long-term blood pressures.38 Patients are encouraged to take all antihypertensive drugs on the day of surgery. SAMBA recommends that cataract surgery should be delayed only for patients with malignant hypertension defined as elevated blood pressures with acute end-organ damage.

Should Patients Presenting for Cataract Surgery With Hypertension Be Administered Intravenous Antihypertensives to “Normalize” Blood Pressures Before Proceeding With Surgery?

Several studies have questioned the accuracy of preoperative mean arterial blood pressures noting both higher than patients’ established ambulatory baseline pressures39,40 and wide variability compared to mean daytime mean arterial pressures.41 Using an overestimated value of a patient’s normal blood pressure to guide perioperative management of hypertension and hypotension can be harmful if inappropriate vasoactive medications are administered, especially when the ideal target blood pressure is unknown.36 Some practitioners occasionally administer blood pressure lowering drugs before cataract surgery to treat or prevent perioperative hypertension. However, acute correction or reduction of blood pressure can be harmful and may lead to hypotension in the perioperative period. One study found only a significant association between low, not elevated, preoperative blood pressures and increased postoperative mortality in an elderly population of patients.2 POQI concluded that there was insufficient data that preoperative blood pressures should alter decisions to proceed with surgery or not, and there is insufficient evidence to support lowering blood pressure in the immediate preoperative period to lower perioperative risk.37 SAMBA recommends against acutely lowering blood pressures for patients anticipating cataract surgery immediately preoperatively.

Do Anticoagulants and Antiplatelets Need to Be Interrupted for Cataract Surgery?

Most agree that antiplatelet agents and anticoagulants do not need to be interrupted for cataract surgery.42 Several studies have shown that it is safe to perform cataract surgery in patients who are taking antiplatelet and anticoagulant medications.43–47 A multicenter study showed that clopidogrel or warfarin was associated with a significant increase in minor complications with periorbital regional anesthesia, but there was no associated significant increase in surgical bleeding or potentially sight-threatening local anesthetic or surgical complications.45 The Royal College of Ophthalmologists recommends that cataract surgery performed with topical or sub-Tenon’s anesthesia may be performed without cessation of dual antiplatelet therapy (DAPT).48 SAMBA recommends continuation of antiplatelet and anticoagulant medications before cataract surgery.

Can Patients With Coronary Stents Have Cataract Surgery Regardless of When Those Stents Were Placed?

The American College of Cardiology and American Heart Association (ACC/AHA) recommend that elective surgery be postponed for 30 days after bare metal stent implantation and 6 months after drug eluting stent implantation.25,26 However, many have argued that this recommendation does not apply to cataract surgery if DAPT are continued. The stress response is muted with cataract surgery. Cataract surgery compared to other surgical procedures elicits a minimal inflammatory response which tends to be local.27,49 SAMBA recommends that patients with coronary stents can have cataract surgery 30 days after coronary artery stent insertion as long as DAPT is continued uninterrupted.

Does New-Onset Atrial Fibrillation Warrant Cancellation of Cataract Surgery?

New onset, or more likely newly discovered, atrial fibrillation may occur on the day of surgery. However, for patients presenting for minor surgical procedures, typically of limited duration and complexity (eg, with minimal anticipated blood loss), it may be reasonable to safely proceed despite new onset atrial fibrillation, as long as the patient is asymptomatic and hemodynamically stable.50 These patients should subsequently be referred for early evaluation and management of atrial fibrillation. SAMBA recommends that cataract surgery not be delayed in patients with atrial fibrillation as long as the patient is asymptomatic with stable hemodynamics.

Can Patients With Implantable Cardiac Defibrillators Be Safely Cared for in a Free-Standing ASC?

It is important to determine the cardiac implantable electronic device (CIED) type, manufacturer, and primary indication for the device.51 This information is generally available from the manufacturer’s identification card given to the patient, a review of the medical record or the most recent CIED interrogation report. Often the underlying condition, such as severe heart failure or malignant arrhythmias are more important than the presence of the device itself.

If patients have had routine follow-up with recommended yearly pacemaker checks and 6-month implantable cardioverter defibrillator (ICD) checks without new concerning symptomatology such as syncope or cardioversions, they can safely proceed with cataract surgery. The only potential concern is the possibility for patient movement if the ICD happens to activate during the surgery. The likelihood of this is quite low in patients who have not experienced recent or escalating episodes of cardioversions. Typically, there is no risk of electromagnetic interference during a cataract procedure. Some pacemakers with rate adaptive mechanisms may have variable pacing rates which can be triggered by changes in breathing, patient movement, or monitoring devices. These pacing rate changes have been mistaken for arrhythmias, so it is important for anesthesia providers to recognize this paced rate variability as normal functioning.52–54 SAMBA recommends that practitioners be familiar with CIED functionality, and against reprogramming devices or use of a magnet for patients having cataract surgery.

Does Hyperglycemia Warrant Cancellation of Cataract Surgery?

There is no evidence to support delaying cataract surgery for any specific blood glucose concentration or hemoglobin A1c.55 The Royal College of Anaesthetists and The Royal College of Ophthalmologists 2012 guidelines for ophthalmic surgery under local anesthesia state that there is insufficient evidence to recommend cancelling surgery above a certain blood glucose concentration.56,57 SAMBA takes a similar approach and recommends only delaying cataract surgery in patients with evidence of ketoacidosis or hyperosmolar hyperglycemic nonketotic syndrome or significant hypoglycemia.58

Should There Be a Weight Limit for Cataract Surgery?

The weight limitation for cataract procedures is based on the weight limit of the stretcher. Most eye stretchers have a weight limit of 300 to 500 lbs. Other considerations include the ability of the patient to transfer themselves or the need for special lifting equipment to ensure patient and employee safety. SAMBA recommends that providers establish and follow institutional guidelines for safe care of obese patients having cataract surgery.

Can an ASA-PS IV Patient Safely Undergo Cataract Surgery in a Free-Standing ASC?

While adverse events are higher in patients with medical comorbidities, cataract surgery is an extremely low risk and highly beneficial procedure. SAMBA recommends that ASA-PS 4 patients with stable comorbidities who can tolerate cataract surgery with topical or regional anesthesia and no or minimal sedation can safely undergo cataract surgery in a free-standing ASC.

Does the Need for General Anesthesia Compared to Topical With or Without Sedation Alter the Risks of Cataract Surgery?

We are unaware of any robust studies comparing the overall risk of cataract surgery done with general anesthesia compared to no general anesthesia. It is unlikely that such a study will ever be done given the rarity of using general anesthesia for cataract surgery. There are a few underpowered, dated studies looking at stress responses with mixed results. However, evidence suggesting direct correlation between stress response and postoperative outcomes is lacking. Furthermore, the general anesthesia techniques used in older studies assessing stress response do not correspond to current anesthesia techniques for cataract surgery which include use of supraglottic devices, maintenance of spontaneous breathing, opioid-sparing, minimal depth of anesthesia, and topical anesthesia as well. Because the overall risks of most surgical procedures are not different based on the type of anesthesia, it is not likely that there is a substantial difference in risk when general anesthesia is provided for cataract surgery. However, SAMBA recommends that medical comorbidities (eg, a patient with a difficult airway, severe pulmonary disease) are considered when deciding to offer general anesthesia for cataract surgery.

Does Preoperative Testing Offer Benefits to Patients Before Cataract Surgery?

It is important to note that the Centers for Medicare and Medicaid Services (CMS) has dropped the requirement for a history and physical examination before surgery. There is no benefit of routine testing of patients with coexisting illnesses before cataract surgery.33,59 Tests are indicated ONLY if the patient presents with a severe medical problem that warrants evaluation even without planned surgery.

The only well-established very low-risk procedure is cataract extraction.29,60 The 2014 ACC/AHA guideline on perioperative cardiovascular evaluation and management of patients undergoing noncardiac surgery specifically states that cardiac risk assessment should not be done before very low-risk surgeries, such as cataract surgery.29 SAMBA recommends no testing before cataract surgery unless indicated independent of the procedure.

What Is Optimal Preoperative Medication Management for Patients Undergoing Cataract Surgery?

SAMBA recommends that patients having cataract surgery can and should typically continue all of their routine medications throughout the perioperative period.


    1. Masud T, Morris RO. Epidemiology of falls. Age Ageing. 2001;30(suppl 4):3–7.
    2. Ivers RQ, Norton R, Cumming RG, Butler M, Campbell AJ. Visual impairment and risk of hip fracture. Am J Epidemiol. 2000;152:633–639.
    3. Cummings SR, Nevitt MC, Browner WS, et al. Risk factors for hip fracture in white women. Study of Osteoporotic Fractures Research Group. N Engl J Med. 1995;332:767–773.4. Ivers RQ, Cumming RG, Mitchell P, Simpson JM, Peduto AJ. Visual risk factors for hip fracture in older people. J Am Geriatr Soc. 2003;51:356–363.
    5. Meuleners LB, Hendrie D, Lee AH, Ng JQ, Morlet N. The effectiveness of cataract surgery in reducing motor vehicle crashes: a whole population study using linked data. Ophthalmic Epidemiol. 2012;19:23–28.
    6. McGwin G Jr, Chapman V, Owsley C. Visual risk factors for driving difficulty among older drivers. Accid Anal Prev. 2000;32:735–744.
    7. Owsley C, Stalvey BT, Wells J, Sloane ME, McGwin G Jr. Visual risk factors for crash involvement in older drivers with cataract. Arch Ophthalmol. 2001;119:881–887.
    8. Subzwari S, Desapriya E, Scime G, Babul S, Jivani K, Pike I. Effectiveness of cataract surgery in reducing driving-related difficulties: a systematic review and meta-analysis. Inj Prev. 2008;14:324–328.
    9. Wood JM, Carberry TP. Bilateral cataract surgery and driving performance. Br J Ophthalmol. 2006;90:1277–1280.
    10. Owsley C, Stalvey B, Wells J, Sloane ME. Older drivers and cataract: driving habits and crash risk. J Gerontol A Biol Sci Med Sci. 1999;54:M203–M211.
    11. Owsley C, McGwin G Jr, Sloane M, Wells J, Stalvey BT, Gauthreaux S. Impact of cataract surgery on motor vehicle crash involvement by older adults. JAMA. 2002;288:841–849.
    12. Taylor HR, Pezzullo ML, Keeffe JE. The economic impact and cost of visual impairment in Australia. Br J Ophthalmol. 2006;90:272–275.
    13. Hodge W, Horsley T, Albiani D, et al. The consequences of waiting for cataract surgery: a systematic review. CMAJ. 2007;176:1285–1290.
    14. De Coster C, Dik N, Bellan L. Health care utilization for injury in cataract surgery patients. Can J Ophthalmol. 2007;42:567–572.
    15. Wang JJ, Mitchell P, Cumming RG, Smith W; Blue Mountains Eye Study. Visual impairment and nursing home placement in older Australians: the Blue Mountains Eye Study. Ophthalmic Epidemiol. 2003;10:3–13.
    16. Kumar CM, Seet E. Cataract surgery in dementia patients-time to reconsider anaesthetic options. Br J Anaesth. 2016;117:421–425.
    17. Ishii K, Kabata T, Oshika T. The impact of cataract surgery on cognitive impairment and depressive mental status in elderly patients. Am J Ophthalmol. 2008;146:404–409.
    18. Lundström M, Pesudovs K. Catquest-9SF patient outcomes questionnaire: nine-item short-form Rasch-scaled revision of the Catquest questionnaire. J Cataract Refract Surg. 2009;35:504–513.
    19. Fong CS, Mitchell P, Rochtchina E, Teber ET, Hong T, Wang JJ. Correction of visual impairment by cataract surgery and improved survival in older persons: the Blue Mountains Eye Study cohort. Ophthalmology.
    20. Fong CS, Mitchell P, Rochtchina E, de Loryn T, Tan AG, Wang JJ. Visual impairment corrected via cataract surgery and 5-year survival in a prospective cohort. Am J Ophthalmol. 2014;157:163–170.e1.
    21. Conner-Spady B, Sanmartin C, Sanmugasunderam S, et al. A systematic literature review of the evidence on benchmarks for cataract surgery waiting time. Can J Ophthalmol. 2007;42:543–551.
    22. Jeganathan VS, Wang JJ, Wong TY. Ocular associations of diabetes other than diabetic retinopathy. Diabetes Care. 2008;31:1905–1912.
    23. MacPherson R. Structured assessment tool to evaluate patient suitability for cataract surgery under local anaesthesia. Br J Anaesth. 2004;93:521–524.
    24. Thilen SR, Treggiari MM, Lange JM, Lowy E, Weaver EM, Wijeysundera DN. Preoperative consultations for medicare patients undergoing cataract surgery. JAMA Intern Med. 2014;174:380–388.
    25. Chen CL, Lin GA, Bardach NS, et al. Preoperative medical testing in Medicare patients undergoing cataract surgery. N Engl J Med. 2015;372:1530–1538.
    26. Keay L, Lindsley K, Tielsch J, Katz J, Schein O. Routine preoperative medical testing for cataract surgery. Cochrane Database Syst Rev. 2012:CD007293.
    27. Egholm G, Kristensen SD, Thim T, et al. Risk associated with surgery within 12 months after coronary drug- eluting stent implantation. Am Coll Cardiol. 2016;68:2622–2632.
    28. Levine GN, Bates ER, Bittl JA, et al. 2016 ACC/AHA Guideline Focused Update on Duration of Dual Antiplatelet Therapy in Patients With Coronary Artery Disease: a Report of the American College of Cardiology/American Heart Association Task Force on Clinical Practice Guidelines: an Update of the 2011 ACCF/AHA/SCAI Guideline for Percutaneous Coronary Intervention, 2011 ACCF/AHA Guideline for Coronary Artery Bypass Graft Surgery, 2012 ACC/AHA/ACP/AATS/PCNA/SCAI/STS Guideline for the Diagnosis and Management of Patients With Stable Ischemic Heart Disease, 2013 ACCF/AHA Guideline for the Management of ST-Elevation Myocardial Infarction, 2014 AHA/ACC Guideline for the Management of Patients With Non-ST-Elevation Acute Coronary Syndromes, and 2014 ACC/AHA Guideline on Perioperative Cardiovascular Evaluation and Management of Patients Undergoing Noncardiac Surgery. Circulation. 2016;134:e123–e155.
    29. Fleisher LA, Fleischmann KE, Auerbach AD, et al.; American College of Cardiology; American Heart Association. 2014 ACC/AHA guideline on perioperative cardiovascular evaluation and management of patients undergoing noncardiac surgery: a report of the American College of Cardiology/American Heart Association Task Force on practice guidelines. J Am Coll Cardiol. 2014;64:e77–137.
    30. Canet J, Sanchis J, Briones Z, et al. Recent acute respiratory tract infection in adults is a significant risk factor of postoperative complications. Eur J Anesthesiol. 2008;25:72–73.
    31. Jorgensen ME, Torp-Pedersen C, Gislason GH, et al. Time elapsed after ischemic stroke and risk of adverse cardiovascular events and mortality following elective noncardiac surgery. JAMA. 2014;312:269–277.
    32. Cremer A, Amraoui F, Lip GY, et al. From malignant hypertension to hypertension-MOD: a modern definition for an old but still dangerous emergency. J Hum Hypertens. 2016;30:463–466.
    33. Magri MP, Espindola RF, Santhiago MR, Mercadante EF, Kara Junior N. Cancellation of cataract surgery in a public hospital. Arq Bras Oftalmol. 2012;75:333–336.
    34. Bamashmus M, Haider T, Al-Kershy R. Why is cataract surgery canceled? A retrospective evaluation. Eur J Ophthalmol. 2010;20:101–105.
    35. Guerrier G, Rondet S, Hallal D, et al. Risk factors for intraoperative hypertension in patients undergoing cataract surgery under topical anaesthesia. Anaesth Crit Care Pain Med. 2016;35:343–346.
    36. Kumar CM, Seet E, Eke T, Joshi GP. Hypertension and cataract surgery under loco-regional anaesthesia: not to be ignored? Br J Anaesth. 2017;119:855–859.
    37. Sanders RD, Hughes F, Shaw A, ; Perioperative Quality Initiative-3 Workgroup; POQI chairs; Physiology group; Preoperative blood pressure group; Intraoperative blood pressure group; Postoperative blood pressure group. Perioperative Quality Initiative consensus statement on preoperative blood pressure, risk and outcomes for elective surgery. Br J Anaesth. 2019;122:552–562.
    38. Hartle A, McCormack T, Carlisle J, et al. The measurement of adult blood pressure and management of hypertension before elective surgery: Joint Guidelines from the Association of Anaesthetists of Great Britain and Ireland and the British Hypertension Society. Anaesthesia. 2016;71:326–337.
    39. van Klei WA, van Waes JA, Pasma W, et al. Relationship between preoperative evaluation blood pressure and preinduction blood pressure: a cohort study in patients undergoing general anesthesia. Anesth Analg. 2017;124:431–437.
    40. National Institute for Healthcare and Care Excellence. Cataract in adults: management. NICE guideline. 2017. Accessed February 20, 2021.
    41. Saugel B, Reese PC, Sessler DI, et al. Automated ambulatory blood pressure measurements and intraoperative hypotension in patients having noncardiac surgery with general anesthesia: a prospective observational study. Anesthesiology. 2019;131:74–83.
    42. Kumar CM, Seet E. Stopping antithrombotics during regional anaesthesia and eye surgery: crying wolf? Br J Anaesth. 2017;118:154–158.
    43. Benzimra JD, Johnston RL, Jaycock P, et al. The Cataract National Database Electronic multicentre audit of 55 567 operations: antiplatelet and anticoagulant medications. Eye (Lond). 2009;23:10–16.
    44. Katz J, Feldman MA, Bass EB, et al.; Study of Medical Testing for Cataract Surgery Team. Risks and benefits of anticoagulant and antiplatelet medication use before cataract surgery. Ophthalmology. 2003;110:1784–1788.
    45. Kumar N, Jivan S, Thomas P, McLure H. Sub-Tenon’s anesthesia with aspirin, warfarin, and clopidogrel. J Cataract Refract Surg. 2006;32:1022–1025.
    46. Jonas JB, Pakdaman B, Sauder G. Cataract surgery under systemic anticoagulant therapy with coumarin. Eur J Ophthalmol. 2006;16:30–32.
    47. Barequet IS, Sachs D, Priel A, et al. Phacoemulsification of cataract in patients receiving Coumadin therapy: ocular and hematologic risk assessment. Am J Ophthalmol. 2007;144:719–723.
    48. Makuloluwa AK, Tiew S, Briggs M. Peri-operative management of ophthalmic patients on anti-thrombotic agents: a literature review. Eye (Lond). 2019;33:1044–1059.
    49. De Maria M, Iannetta D, Cimino L, Coassin M, Fontana L. Measuring anterior chamber inflammation after cataract surgery: a review of the literature focusing on the correlation with cystoid macular edema. Clin Ophthalmol. 2020;14:41–52.
    50. Spragg D, Prukin JM. Accessed February 15, 2021.
    51. Practice Advisory for the Perioperative Management of Patients with Cardiac Implantable Electronic Devices: pacemakers and Implantable Cardioverter–Defibrillators 2020. An Updated Report by the American Society of Anesthesiologists Task Force on Perioperative Management of Patients with Cardiac Implantable Electronic Devices. Anesthesiology. 2020;132:225–252.
    52. Chew EW, Troughear RH, Kuchar DL, Thorburn CW. Inappropriate rate change in minute ventilation rate responsive pacemakers due to interference by cardiac monitors. Pacing Clin Electrophysiol. 1997;20:276–282.
    53. Lau W, Corcoran SJ, Mond HG. Pacemaker tachycardia in a minute ventilation rate-adaptive pacemaker induced by electrocardiographic monitoring. Pacing Clin Electrophysiol. 2006;29:438–440.54. Southorn PA, Kamath GS, Vasdev GM, Hayes DL. Monitoring equipment induced tachycardia in patients with minute ventilation rate-responsive pacemakers. Br J Anaesth. 2000;84:508–509.
    55. Kumar CM, Seet E, Eke T, Dhatariya K, Joshi GP. Glycaemic control during cataract surgery under loco-regional anaesthesia: a growing problem and we are none the wiser. Br J Anaesth. 2016;117:687–691.
    56. Kumar CM, Eke T, Dodds C, et al. Local anaesthesia for ophthalmic surgery—new guidelines from the Royal College of Anaesthetists and the Royal College of Ophthalmologists. Eye. 2012;26:897–898.
    57. Local anaesthesia for ophthalmic surgery—Joint guidelines from the Royal College of Anaesthetists and the Royal College of Ophthalmologists. Accessed on January 31, 2021.
    58. Joshi GP, Chung F, Vann MA, et al.; Society for Ambulatory Anesthesia. Society for Ambulatory Anesthesia consensus statement on perioperative blood glucose management in diabetic patients undergoing ambulatory surgery. Anesth Analg. 2010;111:1378–1387.
    59. Lira RP, Nascimento MA, Moreira-Filho DC, Kara-José N, Arieta CE. Are routine preoperative medical tests needed with cataract surgery? Rev Panam Salud Publica. 2001;10:13–17.
    60. Schein OD, Katz J, Bass EB, et al. The value of routine preoperative medical testing before cataract surgery. Study of Medical Testing for Cataract Surgery. N Engl J Med. 2000;342:168–175.