Medical Fitness Before Eye Surgery: BP, Sugar, Tamsulosin, GLP-1 and SGLT2
Last updated: November 2026
Most eye surgery is done under local anaesthesia, so very few medical problems are a reason to cancel. The aim of the pre-operative check is to find the few that are: uncontrolled blood pressure or sugar, a patient who cannot lie flat, a drug that changes the surgery, and an unstable heart or chest. Here are the thresholds and drug rules most units use.
Quick thresholds
| Check | Proceed if | Comments |
|---|---|---|
| Blood pressure | Below 180/110 mmHg on the day (UK anaesthesia and hypertension societies) | Above this, recheck after rest; defer elective surgery and refer to the physician if it stays high. Do not stop the usual antihypertensives on the day. |
| Blood sugar | A reasonable random glucose on the day (many Indian units accept up to about 200–250 mg/dL for local anaesthesia surgery) | No HbA1c cut-off is required for cataract under local anaesthesia, but a high HbA1c means more post-operative inflammation and macular oedema: optimise diabetic retinopathy and DME first. |
| Lying flat | The patient can lie flat and still for 20–30 minutes | Check for heart failure, COPD, back problems, tremor, cough, claustrophobia, dementia and hearing loss; plan sedation or general anaesthesia if needed. |
| Recent heart attack or stroke | Usually wait at least 3 months for elective surgery | Discuss with the physician, especially if antiplatelets have just been started. |
| Infection | No active lid, conjunctival or lacrimal infection | Treat blepharitis, and check for regurgitation on pressure over the lacrimal sac; postpone if there is a chest or urinary infection with fever. |
Drugs that matter for eye surgery
| Drug | Why it matters | What to do |
|---|---|---|
| Tamsulosin and other alpha-1 blockers (alfuzosin, silodosin; also some antipsychotics) | Intraoperative floppy iris syndrome (IFIS): poor dilation, iris billowing and prolapse | Do not stop; stopping does not help, as the effect persists. Plan for IFIS: intracameral phenylephrine or epinephrine, dispersive viscoelastic, iris hooks or a ring, and an experienced surgeon. |
| Antiplatelets and anticoagulants | Bleeding with blocks and some procedures | See the antithrombotics page; continue for most cataract surgery. |
| GLP-1 receptor agonists (semaglutide, liraglutide, dulaglutide, tirzepatide) | Delayed stomach emptying: aspiration risk if sedation or general anaesthesia is used | Most patients can continue (2024 multi-society guidance). For sedation or GA, follow anaesthesia advice: a liquid-only diet for 24 hours before, and defer elective surgery during dose escalation or if GI symptoms are present. Topical anaesthesia without sedation is little affected. |
| SGLT2 inhibitors (dapagliflozin, empagliflozin, canagliflozin) | Euglycaemic ketoacidosis with fasting | For surgery needing fasting or GA: stop 3 days before (ertugliflozin 4 days), per FDA. Usually continue for cataract under topical anaesthesia without fasting; follow local protocol. |
| Insulin and oral hypoglycaemics | Hypoglycaemia if fasting | Most cataract surgery needs no fasting: give usual medicines and breakfast. If fasting is needed, follow the diabetes team's plan. |
| Steroids (long-term) | Adrenal suppression, poor healing, raised IOP | Continue; consider stress-dose cover for major surgery under GA. |
| Bisphosphonates | Can cause scleritis or uveitis | Not a reason to cancel; ask about past ocular inflammation. |
| Finasteride and dutasteride | Associated with IFIS in some reports, but weakly | Mention it to the surgeon. |
| Hydroxychloroquine, ethambutol, amiodarone | Ocular toxicity that may limit the visual result | Document a baseline fundus and OCT; see hydroxychloroquine screening. |
Investigations: what is really needed?
For cataract surgery under local anaesthesia in a well patient, routine blood tests, ECG and chest X-ray do not reduce complications. Test according to the patient: blood sugar in diabetes, INR on warfarin, ECG for symptoms of heart disease or an irregular pulse, and urea, creatinine and electrolytes for patients on diuretics or with kidney disease, especially if a block or general anaesthesia is planned. Follow your hospital and insurance requirements.
Where residents slip
- Stopping tamsulosin before surgery: it does not reduce IFIS.
- Cancelling for a BP of 170/100 that settles with rest.
- Starving a diabetic patient on insulin for a topical cataract.
- Forgetting to ask whether the patient can lie flat.
Key sources
- Hartle A, et al. The measurement of adult blood pressure and management of hypertension before elective surgery: joint guidelines from the AAGBI and the British Hypertension Society. Anaesthesia. 2016;71:326-337
- Multi-society clinical practice guidance for the safe use of GLP-1 receptor agonists in the perioperative period (ASA, AGA, ASMBS, ISPOR and SAGES). 2024
- US Food and Drug Administration. Drug safety labelling change: stop SGLT2 inhibitors before scheduled surgery. 2020
- Chang DF, Campbell JR. Intraoperative floppy iris syndrome associated with tamsulosin. J Cataract Refract Surg. 2005;31:664-673
- Keay L, et al. Routine preoperative medical testing for cataract surgery. Cochrane Database Syst Rev. 2019
Related: Cataract pre-op risk checklist, Biometry checklist, Antithrombotics and eye surgery.
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