Ocular anesthesia trends toward ‘fewer needles, no pain’

Various innovations in technology and methods have revolutionized ocular surgery by maximizing outcomes and safety, shortening surgical time and reducing stress on patients.

Patient comfort and immobility are also critical to surgical success and safety, and anesthesia plays a key role. Currently, ophthalmic surgeons use intravenous sedation and topical or infiltration methods such as retrobulbar anesthesia, peribulbar anesthesia and subconjunctival anesthesia to achieve akinesia.

Patients expect less invasive and painless surgery, according to Melissa Toyos, MD, FACS.

“We’re dealing with people with higher levels of expectations. They’re not necessarily willing or used to suffering in any way. They definitely want to be comfortable,” she said. “I think all of the trends are less invasive — fewer needles, no pain.”

In the past, ophthalmic surgeons would perform retrobulbar and peribulbar blocks, in which local anesthetic is injected behind the eye, according to John P. Berdahl, MD. The long-acting anesthetics would prevent the eye from moving and make the surgery painless. “However, nobody really loves having a needle stuck behind their eye,” he said.

Image: Toyos M

Whereas a block might still be preferred for more complex anterior segment surgeries, cataract surgeons generally prefer sedation and intraocular anesthetics for more routine procedures. For retinal procedures, a local anesthetic or block may be preferred. And for ophthalmic procedures in children, general anesthesia is the norm.

Practices and preferences

Retrobulbar block and peribulbar block are generally safe for more complex surgeries, such as cornea transplant and glaucoma procedures, but for cataract surgery it is uncommon, according to Berdahl.

“There are still pockets in the United States where people do a lot of retrobulbar blocks, but for the most part it is not common,” he said.

Toyos expressed a similar observation about blocking anesthesia.

“I can’t even remember the last time I blocked a patient,” she said. “I think retrobulbar in terms of cataract surgery is probably no longer even considered the standard of care.”

Retrobulbar block and peribulbar block involve potential risks such as double vision, globe puncture and even death, Berdahl said.

“The needle could be injected into the cerebral spinal fluid space and cause central nervous system depression. That has been reported,” he said.

In one case reported by Krilis and colleagues, transient complete vision loss and partial third nerve palsy occurred in one eye following cataract surgery under local anesthesia in the fellow eye. The authors theorized that peribulbar block was associated with ipsilateral trans-optic nerve sheath spread. They believed the case was the first report of contralateral amaurosis and oculomotor nerve palsy following peribulbar anesthesia. However, in a meta-analysis published by Lee and colleagues, there was no clinically or statistically significant difference found in the risk of posterior capsule rupture after phacoemulsification when either akinetic local anesthesia, including sub-Tenon’s, peribulbar and retrobulbar, or kinetic local anesthesia, including topical or topical and intracameral, was used.

Additives such as Hylenex (hyaluronidase, Halozyme Therapeutics) and other agents improve the absorption of anesthetic in the retrobulbar space, Berdahl said.

Patients can “pretty comfortably” undergo cataract surgery with sedation and intraocular anesthetics, according to Berdahl.

“You give a couple of topical eye drops in combination with some intracameral injection of preservative-free anesthetics, mostly to numb the iris,” he said.

Toyos said she uses intracameral and topical anesthesia for cataract patients, but a modified retrobulbar injection is used for patients undergoing glaucoma surgery with the Iridex Cyclo G6 laser.

“It is one place where I feel like I’ve taken a little bit of a step backward ... because retrobulbar is a little bit like saying you’re going back to the ’80s for your hairstyle,” Toyos said. “[The procedure] is intense enough that patients need more than topical anesthesia, so I give a modified retrobulbar with the option of oral Valium to make them comfortable.”

Toyos said she and colleagues have considered the use of oral Valium for some patients but rejected that idea.

“Especially when you’re doing bilateral surgery, I really appreciate [the ability to give] a good shot of Versed (midazolam) or propofol at an appropriate moment. I don’t see us getting away from that altogether,” Toyos said.

Retina procedures

Retina procedures such as vitrectomy and scleral buckle are generally performed in the operating room or ASC with local anesthesia such as peribulbar block or retrobulbar block, according to OSN Retina/Vitreous Board Member Pravin U. Dugel, MD.

“The topical anesthesia, by and large, is the territory of the anterior segment surgeons. But for retina, because we are manipulating the globe and because our incision site is on the side, we use local anesthesia,” Dugel said. “Topical anesthesia has been talked about and there are some case reports of people using it, but by and large, the vast majority of people use retrobulbar or peribulbar anesthesia or general anesthesia. I don’t know anybody who routinely uses topical anesthesia with retina.”

In a study by Mahajan and colleagues, topical anesthesia without sedation was seen as a viable alternative to peribulbar block for select patients undergoing vitrectomy.

For intravitreal injections performed in the clinic or office, most surgeons prefer topical anesthesia, Dugel said. However, he prefers subconjunctival anesthesia for intravitreal injections.

“The reason that I prefer to do subconjunctival anesthesia is because I think that allows me to give better patient comfort,” he said. “If you think about [patients] getting many injections over sometimes years and years, all you need is one bad experience and the patient will remember that one bad experience as opposed to 20 pain-free injections. So, I’m probably in the minority, but I prefer subconjunctival anesthesia for my intravitreal injections, whereas I think a majority of my colleagues would prefer topical anesthesia.”

New directions

Conscious sedation with a sublingual agent may be the new direction of ophthalmic anesthesia, according to Y. Ralph Chu, MD.

“Patients are sort of demanding it. It does lend itself toward more efficient use of resources in terms of anesthesia staff and nursing staff,” Chu said.

The majority of cataract surgery cases involve starting an IV for sedation and then using topical anesthesia; however, for many patients, starting an IV is the most painful part of the cataract surgery procedure, according to Berdahl. As an alternative to the IV, some surgeons use midazolam syrup placed sublingually and intravenous ketamine to provide sedation for cataract surgery.

“[It] also had the nice benefit that they have this ketamine stare, kind of a zombie gaze. You get this benefit of stabilizing the eye that you get with retrobulbar block, but you wouldn’t have to do a retrobulbar block,” Berdahl said.

Berdahl and colleagues have also tried sublingual Versed and sublingual ketamine.

“We were really happy with the anesthesia response that we got because we did get better analgesia, the eye stayed more still, and we got this added side effect of the patient getting this whisper of euphoria and enjoying the procedure more with the ketamine,” he said.

However, the amount of sublingual fluid proved to be uncomfortable for patients. Berdahl and William F. Wiley, MD, medical director of the Cleveland Eye Clinic, helped Imprimis Pharmaceuticals develop MKO Melt, which combines midazolam, ketamine and ondansetron in a compounded formulation in troche format that is administered sublingually. Imprimis launched MKO Melt at the American Society of Cataract and Refractive Surgery meeting in New Orleans.

“It melts in about 2 minutes. The anesthesia starts to take effect very quickly, but about 10 to 20 minutes after you give it is a good time to go to surgery. You can give one, one-and-a-half, two melts, depending on how old the patient is and partly how anxious the patient is, too,” Berdahl said. “It’s easier on and easier off. We’ve done surgeries up to an hour with just the melt, and patients have stayed comfortable. But it doesn’t have the same kind of sharp on, sharp off that IV medication has. Patients also seem to not startle as much or fall asleep as frequently, which is nice because you don’t want them to wake up and be startled while you’re doing surgery.”

According to an Imprimis press release, MKO Melt has been used in more than 1,000 patients undergoing LASIK and cataract surgery.

Chu said that MKO Melt improved efficiency in his surgery center because the greatest delay in the preoperative staging area is setting up IVs. He also noted that it has a calming effect on patients undergoing femtosecond laser-assisted cataract surgery and laser vision correction.

“Actually, for the very nervous laser vision correction patients, like LASIK patients, the MKO Melt, an oral anesthesia, works really well,” he said.

Bilateral surgery

It is unclear whether same-day bilateral sequential cataract surgery will affect anesthesia protocols, Chu said.

“In our practice we don’t perform much bilateral cataract surgery,” he said. “When the risk of anesthesia for a patient with specific medical issues outweighs the benefits of single eye surgery is when we consider bilateral sequential cataract surgery on the same day. In terms of anesthesia, I think IV sedation would give more control given the longer duration of the procedure and the concomitant medical issues that patients may present with.”

In bilateral sequential cases, staff can titrate IV Versed to make it last longer, Chu said.

“There are agents besides traditional Versed and fentanyl that are effective in different situations. We have found good success with propofol and ketamine,” he said.

According to Toyos, the growing popularity of in-office cataract surgery will likely make anesthesiologists more integral to the surgical team.

“I think that when you are doing procedures in office it makes the anesthesia person even that much more important,” Toyos said. “[Very] few ophthalmologists have run codes since their internship and residency, so you need somebody who is ACLS certified in your center. That can be the ophthalmologist, but again, we’re not as familiar with those things.”

Pediatric anesthesia

A great majority of pediatric ophthalmic surgical cases are performed under general anesthesia, according to Robert S. Gold, MD, OSN Pediatrics/Strabismus Section Editor.

“There are some cases that can be done under local such as certain eyelid lesions, including chalazia, depending on the age and cooperation of the child. But the great majority of pediatric cases — strabismus, cataract surgery, whatever it might be — are done under general anesthesia,” Gold said.

Some pediatric ophthalmologists perform tear duct probing procedures in their offices with children restrained, Gold said.

“In my practice, which is now over 30 years, I still put my tear duct probing patients to sleep for a very short period of time. That is something that has been controversial for a long time in our population,” he said.

There have been recent concerns about general anesthesia interfering with neurocognitive development in some children, Gold said.

“In my practice, I do discuss anesthesia with the parents. I discuss that these are always concerns but that your child has been recommended to have surgery. The surgery is a very short process, and the chances of there being any neurocognitive developmental issues are very small. There’s continuing research that is ongoing with that,” Gold said.

A website, www.smarttots.org, reports that studies on neurocognitive function after surgery have not been definitive, Gold said.

In Anesthesiology, O’Leary and colleagues reported that children who underwent surgery before primary school age were at an increased risk of early developmental delay, but the magnitude of difference between exposed and unexposed children was small.

Mark W. Crawford, MBBS, FRCPC, anesthesiologist-in-chief at the Hospital for Sick Children, University of Toronto, and one of the study’s authors, said the results corroborated similar findings that general anesthesia has little or no effect on early cognitive development.

“Our findings were quite clear. There was some statistically significant difference, and that was because of the power of our study. Because it was a very large sample size, we had very high statistical power to detect differences,” Crawford said. “When we looked at the actual magnitude of the difference, it was exceedingly small. It was not a clinically relevant difference whatsoever. This was supportive, then, of a growing body of evidence that there is very little, if any, long-term impact of general anesthesia given early in life.”

In a related editorial in Anesthesiology, Kalkman and colleagues cited the SmartTots’ statement that there is insufficient evidence to advise postponing surgery to a later age.

The GAS study, a multicenter analysis comparing the effects of local and general anesthesia on infants undergoing inguinal hernia repair, also showed that general anesthesia had a minimal impact on neurodevelopment, Crawford said.

Earlier this year, Sun and colleagues reported in the Journal of the American Medical Association that children with a single anesthesia exposure before the age of 36 months and healthy siblings with no anesthesia exposure had similar IQ scores in later childhood. And in the American Journal of Ophthalmology in 2012, Yang and colleagues showed that general anesthesia with sevoflurane in strabismus surgery generally did not affect the intellectual abilities of complex cortical function in children aged 5 to 10 years old at 4 weeks after surgery. However, they showed cortical functions related to hand-eye coordination may be affected by transient changes in postoperative stereoacuity. – by Matt Hasson

• References:
• A multi-site randomized controlled trial comparing regional and general anesthesia for effects on neurodevelopmental outcome and apnea in infants (GAS). https://clinicaltrials.gov/ct2/show/NCT00756600.
• Coelho RP, et al. J Cataract Refract Surg. 2015;doi:10.1016/j.jcrs.2014.06.040.
• Kalkman CJ, et al. Anesthesiology. 2016;doi:10.1097/ALN.0000000000001207.
• Krilis M, et al. J Cataract Refract Surg. 2013;doi:10.1016/j.jcrs.2012.10.019.
• Lam DSC, et al. Am J Ophthalmol. 2012;doi:10.1016/j.ajo.2011.08.040.
• Lee RMH, et al. J Cataract Refract Surg. 2013;doi:10.1016/j.jcrs.2012.11.002.
• Mahajan D, et al. Retina. 2013;doi:10.1097/IAE.0b013e31827ced51.
• O’Leary JD, et al. Anesthesiology. 2016;doi:10.1097/ALN.0000000000001200.
• Reichstein DA, et al. Ophthalmic Surg Lasers Imaging Retina. 2016;doi:10.3928/23258160-20151214-08.
• Sun LS, et al. JAMA. 2016;doi:10.1001/jama.2016.6967.
• Westborg IM, et al. Intracameral anesthesia for cataract surgery, a population-based study patient satisfaction and outcome. Presented at: Association for Research in Vision and Ophthalmology meeting; 2012; Fort Lauderdale, Fla.
• Yang HK, et al. Am J Ophthalmol. 2012;doi:10.1016/j.ajo.2011.09.014.

• For more information:
• John P. Berdahl, MD, can be reached at Vance Thompson Vision, 3101 W. 57th St., Sioux Falls, SD 57108; email: john.berdahl@vancethompsonvision.com.
• Y. Ralph Chu, MD, can be reached at Chu Vision Institute, 9117 Lyndale Ave., South Bloomington, MN 55420; email: yrchu@chuvision.com.
• Mark W. Crawford, MBBS, FRCPC, can be reached at Department of Anesthesia and Pain Medicine, The Hospital for Sick Children Research Institute, Toronto, Ontario, Canada; email: mark.crawford@sickkids.ca.
• Pravin U. Dugel, MD, can be reached at Retinal Consultants of Arizona, 1101 E. Missouri Ave., Phoenix, AZ 85014; email: pdugel@gmail.com.
• Robert S. Gold, MD, can be reached at 790 Concourse Parkway South, Suite 200, Maitland, FL 32751; email: rsgeye@gmail.com.
• Melissa Toyos, MD, FACS, can be reached at Toyos Clinic, 2204 Crestmoor Road, Nashville, TN 37215; email: mtoyos@toyosclinic.com.

Disclosures: Berdahl reports he is a consultant for Imprimis. Chu, Crawford, Dugel, Gold and Toyos report no relevant financial disclosures.

Would you prefer to perform bilateral cataract surgery in children under one session of general anesthesia or in separate sessions?

Simultaneous surgery can expedite recovery

For many of our pediatric patients with strabismus, bilateral surgery during one session of anesthesia is the most effective way to obtain an optimal result. Recessing the lateral rectus muscles in both eyes for divergence excess exotropia is a good example of this, although there are many others. In such cases the increased time under anesthesia is not an issue because it may take just as long to perform a unilateral recession and resection of two horizontal rectus muscles as it does for recessing one muscle in each eye. So if the actual time under anesthesia is the same, what is the advantage of performing surgery in separate anesthesia sessions?

For some, especially with intraocular surgery, it is the possibility of avoiding a devastating bilateral complication such as endophthalmitis. This possibility of the highly unlikely event can be reduced by using a second set of instruments following a second sterile preparation in the second eye being operated on. Because the visual outcome in bilateral congenital cataracts is dependent on the timing of surgery in many cases, simultaneous surgery can expedite the visual rehabilitation process. Some children with underlying systemic disease may present a high risk with each anesthesia, or there can be cumulative adverse effects of multiple anesthesia sessions. I prefer bilateral surgery under one session of general anesthesia when the procedure being performed is more likely to result in a good outcome.

Rudolph S. Wagner, MD, is an OSN Pediatrics/Strabismus Board Member. Disclosure: Wagner reports no relevant financial disclosures.

Bilateral surgery OK but not after 1 year of age

Immediately sequential bilateral pediatric cataract surgery (ISBCS) is gaining in popularity among pediatric surgeons, but it is still far less common than operating one eye at a time. I tell parents that I prefer to operate both eyes together if the child poses more than the average anesthesia risk. When operating congenital cataracts in the first few months of life, I am using ISBCS more often. These eyes are usually left aphakic and have only two small paracentesis openings in the cornea. I place a custom-selected extended-wear aphakic contact lens on each eye at the end of surgery. Each eye is operated with a unique set of instruments, and intracameral antibiotics are used. These children later receive a secondary IOL, usually at age 4 to 5 years.

In children having cataract and IOL surgery at ages above 1 year, I do not favor using ISBCS. These children are at a much higher risk for wound disruption after surgery. Unlike small infants, they can rub the surgical eye with a lot of force and they are prone to falls. In this group, 1 week (or more if older) between eyes is ideal for surgical timing.

M. Edward Wilson, MD, is an OSN Pediatrics/Strabismus Board Member. Disclosure: Wilson reports no relevant financial disclosures.