Clinical significance

•anesthesia4 Sectionin used Agents

effects side ocular induced-Drug • 7 t Pa r

have been reported. These side effects were more common decades ago when the purity of some products was in doubt or before the detergents used to clean equipment were found to be toxic.

Regional anesthesia has caused ocular adverse events but it is difficult to rule out mechanical (speed of injection, bolus effect, increased local pressure) emboli from a toxic effect. Case reports include diplopia after a dental procedure (Walker et al 2004), bilateral transient blindness during hand surgery (Sawyer et al 2002) and permanent uniocular blindness after a dental extraction (Rishiraj et al 2005).

Adverse events secondary to retrobulbar or peribulbar injections of anesthetics are seldom of clinical importance. However, problems may arise secondary to injections into the optic nerve sheath or nerve itself. Irreversible ischemic changes secondary to pressure effects that impede ocular blood flow, direct toxicity to muscle or needle-induced trauma may occur. Myotoxic effects of local anesthetics, which could cause degeneration and subsequent regeneration of extraocular muscles, could explain some cases of postoperative diplopia and ptosis. Han et al (2004) state that persistent diplopia post-retrobulbar anesthesia is due to drug myotoxicity or from direct trauma. Transient loss of vision is practically routine from retrobulbar injections of lidocaine or procaine. There have been occasional reports of cardiopulmonary arrest or grand mal seizures following the ­retrobulbar administration of bupivacaine, lidocaine, mepivacaine or procaine. Warming the anesthetic prior to injection was found by Ursell and Spalton (1996) to decrease the ­iatrogenic pain of the injection.

Inadvertent intraocular injection of a local anesthetic into the anterior chamber is a rare but potentially devastating event. Instances of toxicity to the corneal endothelial cell secondary to local anesthesia have recently increased due to the use of intra­ cameral anesthesia. Judge et al (1997) has reviewed this in animals. Shah et al (2004), along with others, point out that if one uses preservative-free 1% xylocaine (lidocaine), the endothelium is not adversely affected during phacoemulsification. Eggeling et al (2000) concur that lidocaine at 1% appears safe. Dance et al (2005) point out that some patients allergic to ‘caines’ do not react adversely to preservative-free lidocaine. Lee et al (2003) confirm that intracameral 1% lidocaine causes pupillary dilation in the eyes, which are difficult to dilate. Higher concentrations of local anesthetics are toxic to the lens and cornea epithelium.

Inadvertent intraocular injection of lidocaine has been reported to cause cataracts. Pigment dispersion is common, and much of this may be mechanical due to the fire hose effect of a fluid under pressure being forced out through a small gauge needle. The resultant stream has a shearing effect on the tissue it comes into contact with. Pupillary function is often decreased and even absent, partially due to acute secondary glaucoma, synechiae or a direct drug effect. The spectrum of injury is broad; however, if the posterior segment is not involved and chronic glaucoma is avoided, the prognosis may be good with corneal surgery. The outcome of inadvertent local anesthetic injected in the posterior segment is often dependent on the direct effect of the penetration trauma. Although a double perforation may have a better prognosis than a single perforation, an injection through the pars plana may be devoid of significant effects other than the acute rise in intraocular pressure. The immediate effect of the injection is a marked increase in intraocular pressure, with or without pupillary dilation, corneal edema or loss of vision. All of the above are transitory since there appear to be no significant long-term toxic effects of the local anesthetic on the retina or optic nerve. The chief concern is control of the acute rise in pressure, which may be severe enough to cause central retinal

venous or arterial occlusion. Next are the problems from retinal perforation, vitreous adhesion or retinal detachment. Lemagne et al (1990) reported a case of Purtscher-like retinopathy with a retrobulbar injection of a local anesthetic. The exudates and hemorrhages disappeared while a localized paracentral scotoma and afferent pupillary defect were permanent.

Numerous systemic reactions from topical ocular applications of local anesthetics have been reported. Many of these occur in part from the fear of the impending procedure or possibly an oculocardiac reflex. Side effects reported include syncope, convulsions and anaphylactic shock.

Local anesthetics applied to the eye are seldom of importance except with multiple repeat exposures.

References and Further Reading

Anderson NJ, Woods WD, Terry K, et al. Intracameral anesthesia. Arch Ophthalmol 117: 225–232, 1999.

Antoszyk AN, Buckley EG. Contralateral decreased visual acuity and extraocular palsies following retrobulbar anesthesia. Ophthalmology 93: 462, 1986.

Breslin CW, Nershenfeld S, Motolko M. Effect of retrobulbar anesthesia on ocular tension. Can J Ophthalmol 18: 223, 1983.

Carruthers JDA, Sanmugasunderan S, Mills K, et al. The efficacy of topical corneal anesthesia with 0.5% bupivacaine eyedrops. Can J Ophthalmol 30(5): 264–266, 1995.

Cohen RG, Hartstein M, Ladav M, et al. Ocular toxicity following topical application of anesthetic cream to the eyelid skin. Ophthalmic Surg Lasers 27: 374–377, 1996.

Dance D, Basti S, Koch DD. Use of preservative-free lidocaine for cataract surgery in a patient allergic to ‘caines’. J Cataract Refract Surg 31: 848–850, 2005.

Duker JS, et al. Inadvertent globe perforation during retrobulbar and peribulbar anesthesia. Patient characteristics, surgical management, and visual outcome. Ophthalmology 98(4): 519–526, 1991.

Eggeling P, Pleyer U, Hartmann C, et al. Corneal endothelial toxicity of different lidocaine concentrations. J Cataract Refract Surg 6: 1403–1408, 2000.

Eltzschig H, Rohrbach M, Hans Schroeder T. Methaemoglobinaemia after peribulbar blockade: An unusual complication in ophthalmic surgery. Br J Ophthalmol 84: 439, 2000.

Gild WM, et al. Eye injuries associated with anesthesia. A closed claims analysis. Anesthesiology 76: 204–208, 1992.

Gills JP. Effect of lidocaine on lens epithelial cells. J Cataract Refract Surg 30: 1152–1153, 2004.

Haddad R. Fibrinous iritis due to oxybuprocaine. Br J Ophthalmol 73: 76–77, 1989.

Han SK, Kim JH, Hwang J-M. Persistent diplopia after retrobulbar anesthesia. J Cataract Refract Surg 30: 1248–1253, 2004.

Judge AJ, Najafi K, Lee DA, et al. Corneal endothelial toxicity of topical anesthesia. Ophthalmology 104: 1373–1379, 1997.

Kim T, Holley GP, Lee JH, et al. The effects of intraocular lidocaine on the corneal endothelium. Ophthalmology 105(1): 125–130, 1998.

Lee JJ, Moster MR, Henderer JD, et al. Pupil dilation with intracameral 1% lidocaine during glaucoma filtering surgery. Am J Ophthalmol 136: 201–203, 2003.

Lemagne JM, et al. Purtscher-like retinopathy after retrobulbar anesthesia. Ophthalmology 97(7): 859–861, 1990.

Lincoff N, et al. Intraocular injection of lidocaine. Ophthalmology 92: 1587, 1985.

Meyer D, Hamilton RC, Gimbel HV. Myasthenia gravis-like syndrome induced­ by topical ophthalmic preparations. A case report. J Clin Neuro-ophthalmol 12(3): 210–212, 1992.

Mukherji S, Esakowitz L. Orbital inflammation after sub-tenon’s anesthesia. J Cataract Refract Surg 31: 2221–2223, 2005.

Rishiraj B, Epstein JB, Fine D, et al. Permanent vision loss in one eye following­ administration of local anesthesia for a dental extraction. Int J Oral Maxillofac Surg 34: 220–223, 2005.

Salama H, Farr AK, Guyton DL. Anesthetic myotoxicity as a cause of restric­ tive strabismus after scleral buckling surgery. Retina 20: 478–482, 2000.

Sawyer RJ, von Schroeder H. Temporary bilateral blindness after acute lidocaine­ toxicity. Anesth Analg 95: 224–226, 2002.

Shah AR, Diwan RP, Vasavada AR, et al. Corneal endothelial safety of intracameral preservative-free 1% xylocaine. Indian J Ophthalmol 52: 133–138, 2004.