5th October 2015
Anesthesia for Cataract Surgery
Patients coming to us for cataract surgery are often veterans of numerous surgical procedures. However, although they may be comfortable with the thought of surgery, they can be quite anxious about the type of anesthesia that will be utilized for their procedure.
We understand this concern. To be successful, our surgery must provide an excellent medical and visual outcome with a minimum of patient stress. Over the course of 30 years and many thousands of cataract surgeries, our anesthesia techniques have become highly refined and patient friendly.
Two methods of anesthesia currently dominate the world of cataract surgery: topical anesthesia, achieved with eye drops, and injection anesthesia, where a needle delivers anesthetic to the tissue around the eye. Let’s look at the advantages and disadvantages of each method from the perspectives of both the patient and the surgeon.
Topical anesthesia uses drops and gels, typically proparacaine and lidocaine, to anesthetize the cornea and conjunctiva. The extraocular muscles and optic nerve are unaffected.
- From the patient’s perspective, the absence of a needle usually decreases the apprehension surrounding surgery, due to the common expectation of less pain.
- Post-operative visual recovery is rapid with topical anesthesia, often with blurred but functional vision immediately afterwards.
- Topical anesthesia does not completely eliminate intra-operative pain. In fact, several studies have noted a statistically significant higher risk of pain compared to a retrobulbar block. 1, 2, 3 Also, topical anesthesia does not affect the discomfort of the surgeon’s lid spring or microscope light.
- Topical anesthesia does not immobilize the extraocular muscles, so the patient must fixate reliably on the microscope light throughout the surgery. The possibility of an inadvertent but damaging eye movement can provoke anxiety in both the patient and surgeon.
Ancillary IV Sedation
The majority of cataract extraction cases performed under topical anesthesia outside of Pacific Cataract and Laser Institute utilize ancillary IV sedation. The main advantage of IV sedation is that it decreases memory of the procedure and any associated pain or discomfort. Disadvantages of ancillary IV sedation include pain during placement of the IV catheter, extra time for the procedure, increased rate of systemic complications, extra time for patient discharge, and impaired thinking that continues after the procedure is complete. For these reasons, our surgeons and anesthesia staff do not use IV sedation. Instead, we use an oral sedative that has a milder effect.
Retrobulbar block uses local anesthetic, typically xylocaine, lidocaine, and hyaluronidase, injected into the tissue inside the extraocular muscle cone, posterior to the equator of the globe. The eye is rendered immobile, pain-free, and non-seeing. These effects wear off within several hours. Until the ability to blink is regained, the eyelid is taped closed to prevent the eye from drying.
- For the patient, a retrobulbar block removes any anxiety that they will make an inadvertent eye movement, and there is much less discomfort from the lid spring or the intense operating microscope light.
- There is a reduced risk of pain during surgery compared to topical anesthesia.
- For the surgeon, a fully immobilized eye presents a more stable surgical environment, with fewer chances of complications as the result of sudden or involuntary movement. This is especially welcome in eyes that are expected to present challenges, including cases of pseudoexfoliation, corneal disease, floppy iris from alpha-agonist inhibitors such as tamsulosin, and traumatic cataracts.
- Many patients are afraid of needles and, despite our best techniques, the injection can be uncomfortable. However, some patients are unnecessarily worried because they mistakenly believe the injection will penetrate the globe. Although we reassure them that this is not the case, the misperception can cause undue anxiety in the days leading up to surgery.
- After the anesthesia wears off and the strip of surgical tape applied to the eyelid at the end of the procedure is removed, vision may include blur, diplopia, and tilted or discolored images. This can last through the evening but is usually gone the morning after surgery.
- Although very rare, there are significant risks to a retrobulbar block. These include a blood vessel nick causing a peri-ocular bruise or hemorrhage, nerve damage causing paresis, globe perforation, or respiratory arrest.
ANCILLARY ORAL SEDATION
For patients who want a sedative, our surgeons prefer to give a very minimal dose of oral sedation. This makes treatment less stressful but allows patients to remain awake and responsive before, during and after the procedure. The sedative effect is small enough that patients are discharged within minutes of surgery and are able to walk without need of wheelchair assistance.
Which is Best?
Many studies have analyzed which form of anesthesia is best and which is preferred by cataract surgery patients. Although there are varying results, one controlled study of patients who experienced both methods discovered interesting findings: 4
- 71.43% preferred retrobulbar anesthesia
- 10.20% preferred topical anesthesia
- 18.37% had no preference
In at least one study, surgeons found cataract surgery slightly more difficult with topical than with retrobulbar anesthesia. 5 Our experience concurs. All of our surgeons are able to use both anesthetic methods safely. But, when neither technique offers a clear advantage, they prefer the safer surgical environment provided by a retrobulbar block.
Some patients’ personalities may suggest one form of anesthesia. For instance, a patient who is highly motivated, has a high pain threshold, easily controls their eyes, can follow the surgeon’s instructions during the procedure, and wants to get straight back into activities after surgery will likely do very well with topical anesthesia.
On the other hand, if a patient can wait several hours for full visual recovery and is more concerned about a painless surgery with the least chance possible for intra-operative complications, a retrobulbar block is a better choice.
We are very sensitive to patient anxiety and have developed numerous techniques to reduce stress, calm fear and make the administration of anesthesia as comfortable as possible. One of the most powerful is calmly talking to patients, letting them know what we are doing every step of the way. We also avoid things that can invoke unnecessary alarm. For instance, our nurse anesthetists make an effort to prevent patients from ever seeing the needle.
Over 96% of PCLI cataract patients who completed our questionnaire in 2014 rated our success in minimizing the discomfort of anesthesia as very good or excellent. When your patients express concern about this part of cataract surgery, sharing our track record may help ease their anxiety..
If you have questions about anesthesia, or any other topic, please always feel free to call our optometric physicians. We are happy to help.
- Boezaart A, Berry R, Nell M. Topical anesthesia versus retrobulbar block for cataract surgery: The patient’s perspective. J Clin Anesth. 2000;12:58-60.
- Rebolleda G, Muñoz-Negrete FJ, Gutierrez-Ortiz C. Topical plus intracameral lidocaine versus retrobulbar anesthesia in phacotrabeculectomy: Prospective randomized study. J Cataract Refract Surg 2001; 27:1214-1220.
- Gombos K, Jakubovits E, Kolos A, et al. Cataract surgery anaesthesia: Is topical anaesthesia better than retrobulbar? Acta Ophthalmol Scand; 2007 May;85(3):309-16.