Intracameral Anesthesia Research Articles

Surgeon experience and patient comfort during clear corneal phacoemulsification under topical local anesthesia

Purpose To evaluate patient comfort during topical anesthesia clear corneal phacoemulsification surgery performed by a surgeon in the learning curve or by an experienced surgeon. Setting Royal Alexandra Hospital, Paisley, Scotland, United Kingdom. Methods This study comprised 46 consecutive patients having phacoemulsification under topical anesthesia of proparacaine 0.5% (Proxymetacaine®). Surgery was performed by a surgeon during his learning curve (n = 20) or by an experienced surgeon (n = 26). No sedation or intracameral anesthesia was used in either group. All patients had clear corneal phacoemulsification with foldable acrylic posterior chamber intraocular lens implantation. Each patient’s subjective experience of overall pain perioperatively (period immediately surrounding and during surgery) and worst pain perceived during surgery was measured immediately after surgery using a 10-point visual analog scale. Results There was no significant difference in patient-reported pain scores for overall pain perioperatively ( P = .47, Wilcoxon rank sum test) and the worst pain perceived during surgery ( P = .32, Wilcoxon rank sum test). Conclusions Topical anesthesia with proparacaine provided similar and reasonable analgesic effects in patients having surgery by a surgeon in the learning curve and those having surgery by an experienced surgeon. The discomfort perceived during surgery performed by an experienced surgeon was less, although not statistically significantly different.

Long-term endothelial cell loss after phacoemulsification: peribulbar anesthesia versus intracameral lidocaine 1%. Heuermann T, Hartmann C, Anders N. J Cataract Refract Surg 2002;28:639–643.

The use of topical anesthesia in cataract surgery has become increasing popular in the past decade. In 1990, only 10% of cataract surgery in the United States was performed with topical anesthesia, while over 33% of cases were done with topical anesthesia in 1998. Most (82%) ophthalmic surgeons supplement topical anesthesia with intracameral lidocaine. There is clinical and experimental evidence that intracameral anesthesia may be toxic to intraocular structures, especially the corneal endothelium, where abnormal ultrastructural and morphologic changes have been reported. There are a few prospective clinical trials with long-term follow-up that specifically address this concern. The authors performed a prospective, randomized clinical trial in which 78 patients undergoing clear corneal phacoemulsification and posterior chamber IOL implantation by a single surgeon (N.A.) received either peribulbar (39 eyes) anesthesia or topical anesthesia supplemented with 0.15 cc of unpreserved 1% lidocaine. The mean surgical time was 12.2 minutes with peribulbar anesthesia and 14.0 minutes with topical/intracameral lidocaine anesthesia (P < .01). After a mean follow-up of 20 ± 5.1 (SD) months, there were no statistically significant differences between the peribulbar and topical/intracameral lidocaine groups in mean preoperative (2,341 vs 2,512 cells/mm2) and postoperative (2,082 vs 2,197 cells/mm2) endothelial cell counts, mean endothelial cell loss from preoperatively to postoperatively (11.11% vs 12.55%), mean endothelial cell size (496 μm vs 470 μm), and the amount of hexagonal cells (58% vs 56%). There were no intraoperative or postoperative complications in either group. The authors conclude that topical anesthesia supplemented with 0.15 cc of unpreserved 1% lidocaine is a safe alternative to peribulbar anesthesia for phacoemulsification.—Michael D. Wagoner

Lidocaine versus ropivacaine for topical anesthesia in cataract surgery

Purpose: To assess the anesthetic efficacy and safety of topical ropivacaine versus topical lidocaine in cataract surgery. Setting: Institute of Ophthalmology, University of Modena and Reggio Emilia, Modena, Italy. Methods: This prospective controlled randomized double-blind study comprised 64 patients scheduled for planned routine cataract extraction. Patients were randomized into 2 groups; 1 received topical ropivacaine 1% and the other, topical lidocaine 4%. The duration of surgery, intraoperative and early postoperative complications, and the need for supplemental intracameral anesthesia were recorded. Intraoperative and postoperative subjective pain was quantified by patients using a scale from 1 to 10. An endothelial cell count was performed preoperatively and 2 months after surgery. Results: The mean endothelial cell density decreased from 2334 cells/mm 2 ± 496 (SD) to 2016 ± 674 cells/mm 2 in the ropivacaine group and from 2519 ± 404 cells/mm 2 to 1847 ± 607 cells/mm 2 in the lidocaine group. The difference in cell density between groups was not significant before ( P = .154) or after surgery ( P = .329); however, the difference in mean cell loss between groups was statistically significant ( P = .031). The duration of surgery and intraoperative complications were the same in both groups. Four patients in the ropivacaine group and 5 in the lidocaine group required supplemental anesthesia ( P > .05). The mean subjective analog pain score was slightly higher in the lidocaine group ( P > .05). The day after surgery, 12 eyes in the ropivacaine group and 6 in the lidocaine group had transient corneal edema ( P = .150). Conclusions: Topical ropivacaine performed at least as well as topical lidocaine in efficacy and safety in cataract surgery. It provided sufficient and long-lasting analgesia without the need for supplemental intracameral anesthesia in most cases.

No-anesthesia clear corneal phacoemulsification versus topical and topical plus intracameral anesthesia: Randomized clinical trial

Purpose: To compare the intraoperative pain scores during clear corneal phacoemulsification under no anesthesia, topical anesthesia, and topical plus intracameral anesthesia. Setting: Dr. Agarwal’s Eye Hospital and Eye Research Center, Chennai, India. Methods: Seventy-five patients were randomized to have phacoemulsification under no anesthesia, topical anesthesia, or topical plus intracameral anesthesia. Uncooperative or illiterate patients and those with hard cataract, a shallow anterior chamber, or small pupils were excluded. A protocol was established for supplemental anesthesia in case of breakthrough pain during the surgery. Each patient was asked to grade the overall severity of intraoperative pain immediately after surgery on a 10-point visual analog scale. Also evaluated were the general discomfort during surgery, discomfort from the microscope lights, surgeon stress during surgery, and total surgical time. Comparison among the 3 groups was performed using an analysis of variance. Results: No supplemental anesthesia was required in any group. No significant difference was noted in the mean scores of the subjective sensation of pain with or without topical anesthesia ( P = .610). The mean scores of patient discomfort from the microscope lights and surgical time were also statistically insignificant. Patient discomfort and surgeon stress during surgery were significantly greater in the no-anesthesia group than in the topical and topical plus intracameral groups ( P = .0235 and P = 0.0206, respectively). Conclusion: No-anesthesia clear corneal phacoemulsification was performed by a highly experienced, skilled surgeon without causing an unacceptable level of pain. However, this technique is not suitable for every cataract surgeon or patient.

Positive and negative dysphotopsia in patients with acrylic intraocular lenses

Purpose To report the incidence, management, and prevention of patient reports of glare and streaks around a point source of light or a dark shadow in the temporal field of vision after acrylic intraocular lens (IOL) implantation. Setting A private practice. Methods Cases in which patients complained vigorously of dysphotopsia were catalogued prospectively during the implantation experience in 6668 consecutive eyes having surgery between January 1995 and June 1999. The techniques of topical–intracameral anesthesia, temporal clear corneal incisions, and phacoemulsification were used in all cases. Alternate IOL styles were selected for use from July 1999 to April 2000. Results Fourteen cases (0.2%) were identified. The complaints resolved in 1, were diminished in 1, and were tolerated without change in 7. Five eyes of 4 patients required IOL exchange with capsular bag placement of a poly(methyl methacrylate) (PMMA) or silicone lens for resolution of symptoms. Selecting alternate IOL styles reduced the incidence of dysphotopsia. Conclusions Glare and streaks from a point source of light represent positive photic expressions of dysphotopsia, and temporal dark shadows represent similar negative photic expressions. Both appear to be associated with shiny square-edge optics made of high-refractive-index acrylic polymer. Intraocular lenses of PMMA and silicone with rounded edges, along with square-edge acrylic IOLs with nonreflective edges, appear less likely to cause clinically significant pseudophakic dysphotopsia.

Rand-Stein analgesia protocol for cataract surgery

Objective To describe the safety and efficacy of an analgesia protocol that enables the surgeon to maintain control over an alert patient experiencing seemingly painless ambulatory cataract surgery, while eliminating the risks and side effects associated with general, local, topical, and intracameral anesthesia. Design Noncomparative, interventional case series. Participants Five thousand one hundred sixty-eight consecutive cataract surgery cases operated on by the same surgeon from April 1, 1993 through June 1, 1998. Methods This technique produces profound ocular analgesia, avoiding any undesired sedative effects, using very low-dose, titrated, intravenous alfentanil. Complete control of the uncooperative patient, including lid squeezing and ocular and general body movements, is obtainable whenever necessary using very low-dose, titrated, intravenous methohexital. Main outcome measures Success was defined as surgery completed in a controlled manner without the need to convert to general, local, topical, or intracameral anesthesia and the patient’s experience being perceived as pain free. Results One hundred percent of the cases were successful without ever deviating from the protocol. Conclusions This analgesia protocol offers advantages for cataract surgery. It virtually eliminates the morbidity of cataract surgery associated with other anesthesia techniques while providing excellent and reliable control. It allows for an immediate postoperative recovery with instantaneous vision restoration. These patients are generally awake, alert, and retain their protective reflexes.

The resiliency of the corneal endothelium to refractive and intraocular surgery.

To describe stress factors (phenylephrine and contact lenses) from the corneal epithelium that can affect the corneal endothelium, and to describe the effects of refractive and intraocular surgery on the corneal endothelial structure and function. Significant clinical and experimental publications are reviewed and recent experiments conducted in the author's laboratory to describe the corneal endothelial stresses. The corneal epithelium serves as a barrier to topical phenylephrine (2.5-10%). In a compromised epithelium, topical phenylephrine will cause drug-induced stromal edema and endothelial vacuolization. Contact lenses are capable of stimulating the epithelial arachidonic acid cascade to release 12(R)hydroxyeicosatetraenoic acid (12(R)HETE) and 8(R)hydroxy-hexadecatrienoic acid (8(R)HHDTrE) to cause endothelial Na+/K+ adenosine triphosphatase (ATPase)-inhibition and polymegethism. Specular microscopy of the corneal endothelial cells after refractive surgery (photorefractive keratectomy [PRK], laser in situ keratomileusis [LASIK], intrastromal rings [INTACs]) has shown that there is minimal effect. However, laser ablation of the stroma within 200 microm of the corneal endothelium will result in endothelial cell structural changes and the formation of the amorphous substance deposited onto Descemet's membrane. Phacoemulsification with a high flow of the irrigation solution can alter the endothelial surface glycoprotein layer. Lidocaine hydrochloride (1%) used as intracameral anesthesia readily diffuses through the corneal endothelium, resulting in stromal uptake and endothelial cell swelling. With phacoemulsification, however, the washout of lidocaine from the cornea (T1/2, 5 minutes) and iris (T1/2, 9 minutes) occurs quickly. Corneal endothelial wound healing after keratoplasty occurs in the following sequence: migration of endothelial cells, development of tight junctions, and the formation of Na+/K+ ATPase pump sites. Corneal endothelial resiliency is due to the increased peripheral endothelial cell number for migration, the ability of endothelial cells to form tight junctions to maintain the endothelial barrier, the increase in endothelial Na+/K+ ATPase pump sites under stress, and the ability of the corneal endothelial cells to shift their metabolism of glucose to the hexose monophosphate shunt for the production of nicotinamide adenine dinucleotide phosphate (NADPH) and membrane repair. All of these factors are important, along with the aqueous humor sodium concentration, which establishes the osmotic gradient for corneal deturgescence and transparency.

Pain relief with intracameral mepivacaine during phacoemulsification

AIMTo assess the efficacy and safety of an intraoperative intracameral injection of mepivacaine, administered when patients experienced pain during the course of cataract surgery under topical anaesthesia.METHODSThis is a prospective...

Efficacy of lidocaine 2% jelly as a topical agent in cataract surgery

Purpose To determine whether lidocaine 2% jelly is an effective topical anesthetic agent for cataract surgery. Setting Private practice and surgicenter. Methods One hundred eighty cataract surgery patients were randomly assigned to 1 of 4 groups of 45 patients each: Group 1—topical eyedrop anesthesia; Group 2—intracameral lidocaine; Group 3—lidocaine 2% jelly applied once, on arrival at the surgicenter; and Group 4—lidocaine 2% jelly applied on arrival and about 5 minutes prior to surgery. Each patient was asked about pain or pressure sensation during the operation and afterward. Results Single instillation of lidocaine 2% jelly was associated with pain scores comparable to those with topical eyedrop anesthesia. When the jelly was readministered shortly before surgery, the pain scores were comparable to those with intracameral anesthesia. Conclusion Lidocaine 2% jelly was an effective agent in cataract surgery.

Comparison of preservative-free bupivacaine vs lidocaine for intracameral anesthesia: a randomized clinical trial and in vitro analysis

Purpose: To determine whether intracameral bupivacaine hydrochloride 0.5% is as effective as lidocaine hydrochloride1.0% in controlling discomfort of patients during phacoemulsification and posterior chamber intraocular lens implantation. In rabbits, corneal endothelial cell function, ultrastructure, and viability were evaluated after in vitro perfusion of bupivacaine 0.5%. Methods: In a double-masked, controlled trial, 48 eyes of 48 patients with uncomplicated age-related cataract were randomly assigned to receive bupivacaine 0.5% or lidocaine 1.0% intracamerally before phacoemulsification with a posterior chamber intraocular lens. Outcome measures such as pain, visual acuity, amount of sedation, length of surgery, pupil size, intraocular pressure, corneal clarity, and anterior chamber reaction were compared. In laboratory studies, paired rabbit corneas were evaluated by endothelial cell perfusion with either bupivacaine 0.5%, bupivacaine 0.5% and glutathione bicarbonate Ringer solution in a 1:1 ratio or bupivacaine 0.5% buffered to a pH of 7.0. The paired control corneas were perfused with glutathione bicarbonate Ringer solution and rates of corneal swelling were determined. Cell ultrastructure and viability were also evaluated. Results: In the randomized trial, there was no significant difference in the pain patients had during surgery or in the early or late postoperative period. No statistically significant difference was seen between the two groups in terms of pupil size, intraocular pressure, corneal edema, anterior chamber reaction, or visual acuity immediately after the operation or on postoperative day 1. Paired rabbit corneas perfused with bupivacaine 0.5% and bupivacaine 0.5% buffered to a pH of 7.0 swelled significantly ( P < .001, P = .009, respectively), and had corneal endothelial cell damage. Dilution of the bupivacaine 1:1 with glutathione bicarbonate Ringer solution prevented corneal edema and damage to the corneal endothelium. Endothelial cell viability was also decreased after perfusion of bupivacaine 0.5% ( P < .001). Conclusions: Clinically, bupivacaine 0.5% is as effective as lidocaine 1.0% for anesthesia during phacoemulsification and posterior chamber intraocular lens implantation. However, in vitro perfusion of bupivacaine 0.5% damaged the corneal endothelium of rabbits except when the drug was diluted 1:1 with glutathione bicarbonate Ringer solution. Surgeons who use 0.2 to 0.5 ml of intracameral bupivacaine 0.5% should be aware of its potential to cause endothelial cell damage because of its lipid solubility. The bupivacaine 0.5% should be diluted at least 1:1 with balanced salt solution before intracameral injection, followed immediately by phacoemulsification. The surgeon should ensure that the bupivacaine 0.5% is nonpreserved and packaged in single-use vials or flip-top containers.

Intracameral anesthesia: in vitro iris and corneal uptake and washout of 1% lidocaine hydrochloride.

To characterize the uptake, washout, and metabolism of lidocaine hydrochloride in the iris/ciliary body and cornea. Iris/ciliary body uptake of lidocaine hydrochloride was measured by incubating human and rabbit irides in radiolabeled carbon 14-1% lidocaine hydrochloride for 2 to 60 minutes. Washout was determined by incubating the iris in 14C-1% lidocaine hydrochloride for 5 minutes and transferring the iris to a series of wells. The wells contained a common intraocular irrigating solution of essential ions, glucose, and glutathione buffered with bicarbonate (an enriched balanced salt solution [BSS PLUS]), which is similar to aqueous humor. Corneal uptake was measured by exposing the endothelial surface to 14C-1% lidocaine hydrochloride for 5 or 15 minutes. Corneal washout was performed after 5-minute exposure to 14C-1% lidocaine hydrochloride using a 2-chambered diffusion apparatus. Samples of the iris, cornea, and BSS PLUS washout solution were analyzed by high-performance liquid chromatography and liquid scintillation spectrometry. In vitro iris/ciliary body uptake of 14C-1% lidocaine hydrochloride follows a logarithmic curve, with 50% to 60% of maximum lidocaine hydrochloride uptake present at 5 minutes. There was no difference in uptake between human, albino rabbit, and pigmented rabbit irides. Washout of lidocaine from the iris occurs with a halflife of 8 to 9 minutes. Corneal uptake of lidocaine was greater after incubation for 15 vs. 5 minutes. The washout of lidocaine from the cornea had a half-life of 5 minutes. Results of high-performance liquid chromatography confirmed that there were no metabolites or breakdown products in the iris, cornea, or washout solution. Lidocaine is taken up quickly by the iris/ ciliary body and cornea and rapidly removed from these tissues after BSS PLUS washout. Irrigation during phacoemulsification seems to limit lidocaine exposure to the ocular tissues, resulting in a short duration of anesthesia. Lidocaine is not metabolized or broken down by the iris or cornea during this short period.

Aqueous humor lidocaine concentrations in topical and intracameral anesthesia

Purpose: To assess aqueous humor lidocaine concentrations in 2 common regimens of topical anesthesia and after intracameral injection of the anesthetic agent.Setting: University hospital eye clinic.Methods: Twenty patients having routine cataract surgery were randomized into 3 groups: 1 given 3 drops of lidocaine 4% before surgery; 1 given 6 drops; 1 given 3 drops plus an intracameral injection of 0.1 mL lidocaine 1%. Lidocaine concentration was measured in aqueous humor samples taken before surgery.Results: With 3 drops, aqueous lidocaine concentration was 1.4 Pg/mL ± 0.5 (SD) and with 6 drops, 4.3 ± 1.5 μg/mL (P = .0015). With an intracameral injection, it was 341.8 ± 152.6 μg/mL.Conclusion: Measurable amounts of lidocaine entered the anterior chamber in topical anesthesia, and more entered when more drops were given. It is likely that concentrations in this range could anesthetize the iris, but they are far lower than concentrations after an intracameral injection.

Effect of intracameral anesthesia on the corneal endothelium

Purpose: To evaluate the effects of intracameral anesthesia on the corneal endothelium.Setting: Department of Ophthalmology, Yokohama City University School of Medicine, Yokohama, Japan.Methods: This study comprised 24 eyes of 12 white rabbits. One eye of 3 rabbits each was injected with preservative-free lidocaine at concentrations of 0.02, 0.2, or 2% and the fellow eye injected with balanced salt solution (BSS®) as a control. The anesthetic agent was injected into the anterior chamber using a bimanual technique. Immediately after enucleation, the cornea was examined by scanning electron microscopy.Results: Scanning electron microscopy revealed no abnormal findings in the eyes injected with lidocaine 0.02 or 0.2% when compared with eyes in the control group. Scanning electron microscopy of the eyes injected with lidocaine 2% showed irregular hexagonal endothelial cells and a significant loss of microvilli.Conclusion: Intracameral anesthesia with high concentrations of lidocaine risks corneal endothelial damage but at the low concentration usually used in cataract surgery did not appear to have an adverse effect. J Cataract Refract Surg 1998; 24:1377-1381

Efficacy and safety of intracameral lidocaine as a supplement to topical anesthesia

Purpose: To establish the benefit of nonpreserved intracameral lidocaine 1 % as an adjunctive anesthetic agent to topical anesthesia for small incision cataract surgery and to determine the agent's safety with respect to corneal toxicity. Setting: Advanced Vision Care, West Hills, California, USA.Methods: A retrospective chart review of cataract surgery performed between January 1995 and March 1997 was done. The efficacy of intracameral lidocaine was determined by comparing the number of topical anesthesia cases (Group 1) and of combined topical and intracameral anesthesia cases (Group 2) that required conversion to a more profound level of local anesthesia, determined by patient discomfort, surgeon discomfort, or both. To determine the presence and bias of a surgical learning curve, Group 1 was subdivided chronologically into two subgroups. Corneal toxicity was assayed by the degree of clinical corneal edema noted by slitlamp examination on the first postoperative day.Results: Six hundred thirty-one charts satisfied the criteria for inclusion; 352 cases (Group 1) had topical anesthesia alone and 279 subsequent cases (Group 2), combined topical and intracameral anesthesia. In Group 1, 42.6% of cases required conversion to some form of additional local anesthesia, whereas in Group 2, less than 1.0% required conversion. In the earlier subgroup, 45.8% of cases required conversion and in the latter, 34.3%. On the first day after surgery, 88.2% of Group 2 cases and 76.7% of Group 1 cases were free from corneal edema. The difference was statistically significant but probably resulted from a change in phaccemulsification technique from sculpting to chopping in the latter cases, which were performed under combined topical and intracameral anesthesia.Conclusions: Intracameral nonpreserved lidocaine 1% appears to be both efficacious and nontoxic as an anesthetic adjunct in small incision cataract surgery.

RETROBULBAR AND POSTERIOR PERIBULBAR ANESTHESIA FOR OPHTHALMIC SURGERY

Retrobulbar and posterior peribulbar anesthesia, often with an associated facial nerve block, have been the gold standard for ophthalmic surgical anesthesia for more than 60 years. It can provide reliable anesthesia and akinesia, resulting in ideal operating conditions for intraocular and orbital procedures. The first attempts at a specific block of the ciliary ganglion were described by Knapp in 1884. 16 The small doses necessitated by the systemic toxicity of the available agents, however, reduced its effectiveness. Cataract surgery in the early part of this century was typically done using topical cocaine, avoiding the risk of systemic complications or even death that were occasionally reported with orbital and general anesthesia. The development of procaine in 1905, although slow to be adopted for ophthalmic anesthesia, allowed safe injection of somewhat larger volumes and more effective blocks. 22 The development of lidocaine, and subsequently the longer acting agents mepivicaine and bupivicaine, enabled almost ideal conditions for ophthalmic surgery while avoiding the expense and risk of general anesthesia. The availability of hyaluronidase was reported by Atkinson in 1949 2 to increase the reliability and rapidity of onset of the block. Hyaluronidase has also allowed injection of much larger volumes of anesthetic without an associated persistent increase in intraocular pressure. Although increasing surgical success and decreasing complication rates have driven a search for ways to improve the safety and patient acceptance of orbital anesthesia, only incremental changes in technique have been made in the last 30 years. The basic block described by Atkinson in 1964, with the noted exception of the position of gaze, has remained a mainstay of ophthalmic anesthesia (PR Honan, personal communication, November, 1996). Although modern phacoemulsification techniques permit safe, relatively rapid routine cataract extraction under topical or intracameral anesthesia, the authors prefer intraconal or peribulbar blocks for most other anterior segment surgery, including penetrating keratoplasty, trabeculectomy, and strabismus procedures. In cataract patients requiring combined procedures, or with an inability to cooperate easily with instructions, we also use orbital blocks or, rarely, general anesthesia.

Outcomes of manual small incision cataract surgery under topical anesthesia with lignocaine 2% jelly

The manual small incision cataract surgery (MSICS) is the surgery of choice in countries with a huge back-log of cataract blindness. To evaluate the outcome of manual small incision cataract surgery (MSICS) under topical anesthesia with lignocaine 2 % jelly. This study was a prospective interventional case series. One hundred and twenty eight patients of senile cataract were operated by MSICS under topical anesthesia using lignocaine 2% jelly. No intra-cameral anesthesia was used. The patients and the single operating surgeon were given a questionnaire to evaluate their experience in terms of pain, surgical experience and complications. The mean pain score was 0.82 (SD +/- 0.97). Seventy-one patients (55.4 %) had a pain score of zero, that is, no pain. One hundred and twenty one patients (94.5 %) had a score of 3 or less, that is, mild to none pain. All the surgeries except two were complication- free and the surgeon's experience was favorable in terms of the patient's cooperation, anterior chamber stability, difficulty, and complications. MSICS can be performed under topical anesthesia with lignocaine jelly, which makes the surgery patient-friendly, without compromising the outcome.