Anesthesia for Cataract Surgery: Options and Safety

Anesthesia for cataract surgery has moved from deep blocks with needles to drops and gels in most cases.

The right choice depends on the patient, the surgeon, and the case.

The safest method is the one that gives a comfortable and still eye with the lowest risk.

Knowing the options helps surgeons to choose well.

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Topical Anesthesia for Cataract Surgery

Staff also apply drops of tetracaine, proparacaine, or lidocaine gel to the surface of the eye.

Also, many surgeons add an intracameral injection of preservative-free lidocaine at the start, which improves comfort during manipulation of the iris and lens.

• Advantages: no needle, quick recovery, no risk of globe perforation or retrobulbar hemorrhage, and no effect on vision after surgery
• Limits: the eye can also move, and sensation during iris and zonular stress may be felt
• Best for: cooperative patients with routine cataracts

Studies show that topical anesthesia is also safe and effective in appropriate patients (see the references).

Anesthesia for Cataract Surgery: Sub-Tenon Anesthesia

The surgeon makes a small cut in the conjunctiva and Tenon capsule, and injects local anesthetic through a blunt cannula into the space around the globe.

• Gives good pain control and some akinesia, with a lower risk of needle injury than other blocks
• Used in patients who cannot tolerate topical anesthesia alone, or for longer cases
• Complications include chemosis, subconjunctival hemorrhage, and rare muscle or optic nerve effects

Trials comparing it with topical anesthesia found better comfort during surgery with the sub-Tenon technique in some settings (see the references).

Peribulbar Anesthesia

The anesthetist places a needle in the orbit outside the muscle cone and injects anesthetic, usually in the lower lid and sometimes the upper.

• Gives akinesia and anesthesia, and is useful for patients who cannot keep the eye still
• More discomfort at injection, and a longer onset than topical anesthesia
• Risks include globe perforation, retrobulbar hemorrhage, and brainstem spread

In addition, peribulbar and retrobulbar blocks have similar efficacy in a Cochrane review, with peribulbar having a lower risk of some complications (see the references).

Anesthesia for Cataract Surgery: Retrobulbar Anesthesia

The anesthetist places the needle inside the muscle cone, behind the globe.

• Gives rapid and dense anesthesia and akinesia
• Carries a higher risk of optic nerve injury, hemorrhage, and respiratory depression from brainstem anesthesia
• Used less often today, but still useful in selected cases

Sedation and General Anesthesia

• Oral or intravenous sedation: helps anxious patients, and requires monitoring
• General anesthesia: for children, patients who cannot lie still, and those who cannot cooperate due to dementia or movement disorders, and for some complicated cases

The anesthetic team should be involved in the planning for these patients.

Choosing the Technique

• Cooperative patient, routine case: topical with or without intracameral anesthetic
• Dense cataract, long case, anxious patient: sub-Tenon or peribulbar block
• Patient with tremor, cough, or claustrophobia: block or general anesthesia
• Anticoagulated patients: doctors usually prefer topical or sub-Tenon methods over sharp needle blocks
• High myopia: avoid sharp needles because of the risk of perforation (see cataract surgery in high myopia)

Preparing the Patient

• Explain what to expect, such as the light and the pressure
• Give a calm and quiet environment, and talk to the patient during surgery
• Check the medical history, blood pressure, and drugs, and ensure that the patient can also lie flat
• Assess the patient’s ability to cooperate

Anesthesia for Cataract Surgery: Complications and Their Management

• Globe perforation: an emergency that needs retinal assessment and often treatment
• Retrobulbar hemorrhage: may need lateral canthotomy and cantholysis if pressure is raised (see orbital compartment syndrome)
• Brainstem anesthesia: requires airway and circulatory support
• Chemosis and muscle problems after sub-Tenon blocks, which usually settle

Anesthesia in Special Patients

• Patients on anticoagulants: topical or sub-Tenon blocks are preferred, since bleeding risk with sharp needles is higher, and the drug is usually continued
• Patients with floppy iris syndrome: extra intracameral drugs and a stable pupil are helpful, with attention to comfort (see floppy iris syndrome)
• Those who cannot lie flat: a position adjusted for comfort, and sedation if needed
• Patients with hearing loss or language barriers: clear signals and an interpreter help the cooperation needed for topical anesthesia

Intracameral Lidocaine

Surgeons inject preservative-free lidocaine 1 percent into the anterior chamber at the start of surgery, in a dose of about 0.1 to 0.5 milliliters.

It reduces pain from iris stretch and from the lens, and it can also be combined with an intracameral mydriatic agent.

Tell patients they may feel pressure and see bright light during the procedure.

Talking Through the Surgery

During topical surgery, a calm voice, a warning before each step, and a simple instruction to look at the light improve comfort and stability.

A team that explains what will happen reduces anxiety, and in many patients no sedation is also required (see phacoemulsification).

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References

1. Davison M, Padroni S, Bunce C, Rüschen H. Sub-Tenon’s anaesthesia versus topical anaesthesia for cataract surgery. Cochrane Database Syst Rev. 2007;(3):CD006291.
2. Alhassan MB, Kyari F, Ejere HOD. Peribulbar versus retrobulbar anaesthesia for cataract surgery. Cochrane Database Syst Rev. 2015;(7):CD004083.
3. Royal College of Ophthalmologists. Cataract Surgery Guidelines. RCOphth; current edition.
4. American Academy of Ophthalmology. Basic and Clinical Science Course, Section 11: Lens and Cataract. AAO; current edition.