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Pupil dilatation with intracameral 1% lidocaine during glaucoma filtering surgery
CORRESPONDENCE Increased Periocular Pigmentation With Ocular Hypotensive Lipid Use in African Americans EDITOR:
susceptibility including race, age, atopy, and other skin diseases.3 Hence, all the subjects may not respond in a similar manner to a particular drug. This is why periocular pigmentation with ocular hypotensive lipid agents may become manifest in some subjects while not in others. PUNITA KUMARI SODHI, MS, DNB
WE READ WITH GREAT INTEREST THE CASE REPORT TITLED
“Increased Periocular Pigmentation With Ocular Hypotensive Lipid Use in African Americans” by Herndon and associates (Am J Ophthalmol 2003;135:713–715). Though periocular pigmentation is a known side effect of bimatoprost,1 this is the first case report of increased periocular pigmentation with this drug. The authors observed that skin color change is induced earlier in patients who use topical bimatoprost than in those who are treated with topical latanoprost. In their opinion, this is most probably due to a difference in concentration of the active agent causing a difference in amount of melanogenesis with two drugs. From our experience of treating the Indian open-angle glaucoma patients with topical latanoprost once a day, we did not come across any patient developing noticeably increased periocular pigmentation until our 1-year follow up.2 On using topical bimatoprost once a day in similar subjects, increased periocular pigmentation was seen to develop with a frequency of one in 10 patients, and the periocular skin color changed within about 2 months of initiating treatment. Hence, we agree with authors that treatment with bimatoprost causes skin color changes earlier than treatment with latanoprost. We feel that this is most probably because bimatoprost has oxidizing properties due to the presence of an amide group,1,3 while latanoprost is only an agonist of PGF2␣, and lacks such oxidizing or reducing properties. Secondly, the adverse skin reactions to topical bimatoprost consist of not only increased periocular pigmentation but also ocular pruritis. The discussion with dermatologists and review of the existing literature on adverse skin reactions to drugs leads us to believe that this entity in fact is a type of cumulative irritant contact dermatitis.3 The cumulative irritant contact dermatitis results from a series of repeated and damaging insults to the skin by a chemical agent. The prostaglandins and 12-hydroxyeicostetraenoic acid (12-HETE) are important chemical mediators in this type of contact dermatitis.4 The irritant contact dermatitis not only depends on chemical and penetration characteristics of a drug but also is influenced by individual 0002-9394/04/$30.00
©
2004 BY
LALIT VERMA, MD
New Delhi, India SIMMI K. RATAN, M CH
Rohtak, Haryana, India
REFERENCES
1. Easthope SE, Perry CM. Topical bimatoprost: A review of its use in open-angle glaucoma and ocular hypertension. Drugs Aging 2002;19(3):231–248. 2. Sodhi PK, Pandey RM, Ratan SK. Efficacy and safety of brimonidine, dorzolamide and latanoprost as adjunctive therapy in patients of primary open angle glaucoma: A randomized controlled trial. Int J Clin Pract 2003;57:875– 878. 3. Wilkinson JD, Willis CM. Contact dermatitis: Irritant. Vol 1. In: Textbook of Dermatology. 6th ed. Champion RH, Burton JL, Burns DA, Breathnach SM, editors. Oxford: Blackwell Science, 1998:709 –731. 4. Sondergaard J, Greaves MW, Jorgensen HP. Recovery of prostaglandins in human primary irritant contact dermatitis. Arch Dermatol 1974;110:556 –558.
Pupil Dilatation With Intracameral 1% Lidocaine During Glaucoma Filtering Surgery IN THE ARTICLE TITLED BY LEE AND ASSOCIATES (AM J
Ophthalmol 2003;136:201–203), the authors used a combination of topical tetracaine along with nonpreserved intracameral lidocaine (1%) in the anterior chamber to produce ocular anesthesia in their glaucoma patients. The topical tetracaine anesthetizes the ocular surface while the intracameral injection of lidocaine anesthetizes the pain sensitive iris tissue. The authors performed trabeculectomy in 25 phakic patients under this anesthesia. We infer that this form of combination anesthesia was used by the authors to circumvent the disadvantages of procedures like peribulbar or retrobulbar injection which are more painful, lengthy, need a larger dose of anesthetic agent, and have an added risk of perforating the globe. Our main consid-
ELSEVIER INC. ALL
RIGHTS RESERVED.
783
eration is the surgery, that is, trabeculectomy in phakic patients for which this form of anesthesia was used by the authors. We feel that any form of manipulation in the anterior chamber including a needle perforation should be avoided in phakic patients. This has an inherent risk of damaging the anterior lens capsule and accelerating the formation of lens opacity. Our second concern is that after pupillary dilation (as with intracameral lidocaine), the iris tends to crowd in the periphery. Hence, the surgeon tends to snip a larger piece of iris while doing peripheral iridectomy following trabecular excision. That is why constriction of pupils is usually advised in patients who have to undergo trabeculectomy. For this, pilocarpine is used both topically (in chronic angle closure patients) and in the form of an intracameral injection. We feel that such combination anesthesia would have been more appropriate if the surgeons had to do cataract extraction along with glaucoma surgery. First, in this combined procedure there is no danger from any sort of manipulation in the anterior chamber. Second, at the conclusion of surgery, an appropriate size periphery iridectomy can be done after constricting pupil with inracameral pilocarpine following intraocular lens insertion. In this study, the authors also measured the pupillary diameter at different instances and made an interesting observation. After intracameral lidocaine injection, the average male pupil diameter was significantly larger at one, three, and five minutes, than the pupil size in females. Additionally, the average pupil diameter in blue iris group was significantly larger at one and three minutes than the brown iris group though there was no significant difference at five minutes. The authors have not explained the probable reason for the difference noticed. A typical reaction of individual iris tissue to a specific chemical structure,1 mechanical immobility caused by pigment granules in the iris,2 or greater accumulation of drug in larger extracellular spaces of heavily pigmented iris tissue3 might be some of the reasons for the difference in response of differentially pigmented irides. Some authors state that physiologically there is no difference between pupillary size of healthy males and females,4 while others state that females have larger pupils.5 On performing the MEDLINE search, we could not find literature on the reason for a difference in response of pupils of males and females to mydriatics. More research work to clarify this aspect is recommended.
2. 3. 4. 5.
AUTHOR REPLY WE APPRECIATE DR. SODHI AND ASSOCIATES COMMENTS
on our study. Dr Sohdi’s main concern centers on the use of lidocaine for phakic trabeculectomies. Specifically, the risk of cataract formation and peripheral iris crowding during intracameral lidocaine injection was raised. We would like to address these points. This study arose in the context of developing a satisfactory method of ocular anesthesia to replace peri- or retro-bulbar injection. At the time of this study, most surgeons we knew were using topical and intracameral anesthesia to perform cataract surgery. We noted that this combination provided excellent anesthesia, and wished to adapt it to trabeculectomy. As for pupil dilation, cataract surgeons were using preoperative mydriatics before surgery. When patients finally received the anesthetic in the operating room, they were already fully dilated. Any additional dilation from the anesthetic was not apparent. We were, therefore, surprised to discover the mydriatic effect when adapting this technique to trabeculectomy surgery. In the United States, most surgeons use a paracentesis in the anterior chamber to evaluate flow at the site of the trabeculectomy. We would like to take this opportunity to clarify that entry into the anterior chamber was with a sharp point blade and the lidocaine delivered with a 27-gauge cannula. The cannula was placed at the lip of the paracentesis and did not enter the anterior chamber. Therefore, there was no risk of an iatrogenic cataract from the intracameral lidocaine injection. In contrast to Dr. Sohdi’s method for trabeculectomy, we never use pilocarpine during a trabeculectomy since the goal is to move the lens diaphragm backward to deepen the anterior chamber. On occasion, dilation can pose a problem when performing the iridectomy. We then put intracameral miochol through the paracentesis to assure that the iridectomy is not excessively large. Since miochol is short lived, the pupil can then return to its normal diameter. At the end of the procedure, however, we commonly administer dilating drops and push the lens diaphragm posterior. Finally, Dr Sodhi and associates request an explanation of the difference in pupil diameter in the subsets of male vs
PUNITA KUMARI SODHI, MS, DNB LALIT VERMA, MD SIMMI K. RATAN, MCH
New Delhi, India
REFERENCES
1. Seidehamel RJ, Tye A, Patil PN. An analysis of ephedrine mydriasis in relationship to iris pigmentation in the guinea-pig
784
AMERICAN JOURNAL
eye in vitro. J Pharmacol Exp Therapeutics 1970;171:205– 213. Venable JP. Glaucoma in the Negro. J Nat Med Ass 1952;44: 7–14. Patil PN. Cocaine-binding by the pigmented and the nonpigmented iris and its relevance to the mydriatic effect. Invest Ophthalmol 1972;11:739 –746. Straub RH, Thies U, Kerp L. The pupillary light reflex. Age dependent and age-independent parameters in normal subjects. Ophthalmologica 1992;204:134 –142. Alexandridis E. Pupil size. In: The Pupil. Springer-Verlag. New York. 1982.
OF
OPHTHALMOLOGY
APRIL 2004
susceptibility including race, age, atopy, and other skin diseases.3 Hence, all the subjects may not respond in a similar manner to a particular drug. This is why periocular pigmentation with ocular hypotensive lipid agents may become manifest in some subjects while not in others. PUNITA KUMARI SODHI, MS, DNB
WE READ WITH GREAT INTEREST THE CASE REPORT TITLED
“Increased Periocular Pigmentation With Ocular Hypotensive Lipid Use in African Americans” by Herndon and associates (Am J Ophthalmol 2003;135:713–715). Though periocular pigmentation is a known side effect of bimatoprost,1 this is the first case report of increased periocular pigmentation with this drug. The authors observed that skin color change is induced earlier in patients who use topical bimatoprost than in those who are treated with topical latanoprost. In their opinion, this is most probably due to a difference in concentration of the active agent causing a difference in amount of melanogenesis with two drugs. From our experience of treating the Indian open-angle glaucoma patients with topical latanoprost once a day, we did not come across any patient developing noticeably increased periocular pigmentation until our 1-year follow up.2 On using topical bimatoprost once a day in similar subjects, increased periocular pigmentation was seen to develop with a frequency of one in 10 patients, and the periocular skin color changed within about 2 months of initiating treatment. Hence, we agree with authors that treatment with bimatoprost causes skin color changes earlier than treatment with latanoprost. We feel that this is most probably because bimatoprost has oxidizing properties due to the presence of an amide group,1,3 while latanoprost is only an agonist of PGF2␣, and lacks such oxidizing or reducing properties. Secondly, the adverse skin reactions to topical bimatoprost consist of not only increased periocular pigmentation but also ocular pruritis. The discussion with dermatologists and review of the existing literature on adverse skin reactions to drugs leads us to believe that this entity in fact is a type of cumulative irritant contact dermatitis.3 The cumulative irritant contact dermatitis results from a series of repeated and damaging insults to the skin by a chemical agent. The prostaglandins and 12-hydroxyeicostetraenoic acid (12-HETE) are important chemical mediators in this type of contact dermatitis.4 The irritant contact dermatitis not only depends on chemical and penetration characteristics of a drug but also is influenced by individual 0002-9394/04/$30.00
©
2004 BY
LALIT VERMA, MD
New Delhi, India SIMMI K. RATAN, M CH
Rohtak, Haryana, India
REFERENCES
1. Easthope SE, Perry CM. Topical bimatoprost: A review of its use in open-angle glaucoma and ocular hypertension. Drugs Aging 2002;19(3):231–248. 2. Sodhi PK, Pandey RM, Ratan SK. Efficacy and safety of brimonidine, dorzolamide and latanoprost as adjunctive therapy in patients of primary open angle glaucoma: A randomized controlled trial. Int J Clin Pract 2003;57:875– 878. 3. Wilkinson JD, Willis CM. Contact dermatitis: Irritant. Vol 1. In: Textbook of Dermatology. 6th ed. Champion RH, Burton JL, Burns DA, Breathnach SM, editors. Oxford: Blackwell Science, 1998:709 –731. 4. Sondergaard J, Greaves MW, Jorgensen HP. Recovery of prostaglandins in human primary irritant contact dermatitis. Arch Dermatol 1974;110:556 –558.
Pupil Dilatation With Intracameral 1% Lidocaine During Glaucoma Filtering Surgery IN THE ARTICLE TITLED BY LEE AND ASSOCIATES (AM J
Ophthalmol 2003;136:201–203), the authors used a combination of topical tetracaine along with nonpreserved intracameral lidocaine (1%) in the anterior chamber to produce ocular anesthesia in their glaucoma patients. The topical tetracaine anesthetizes the ocular surface while the intracameral injection of lidocaine anesthetizes the pain sensitive iris tissue. The authors performed trabeculectomy in 25 phakic patients under this anesthesia. We infer that this form of combination anesthesia was used by the authors to circumvent the disadvantages of procedures like peribulbar or retrobulbar injection which are more painful, lengthy, need a larger dose of anesthetic agent, and have an added risk of perforating the globe. Our main consid-
ELSEVIER INC. ALL
RIGHTS RESERVED.
783
eration is the surgery, that is, trabeculectomy in phakic patients for which this form of anesthesia was used by the authors. We feel that any form of manipulation in the anterior chamber including a needle perforation should be avoided in phakic patients. This has an inherent risk of damaging the anterior lens capsule and accelerating the formation of lens opacity. Our second concern is that after pupillary dilation (as with intracameral lidocaine), the iris tends to crowd in the periphery. Hence, the surgeon tends to snip a larger piece of iris while doing peripheral iridectomy following trabecular excision. That is why constriction of pupils is usually advised in patients who have to undergo trabeculectomy. For this, pilocarpine is used both topically (in chronic angle closure patients) and in the form of an intracameral injection. We feel that such combination anesthesia would have been more appropriate if the surgeons had to do cataract extraction along with glaucoma surgery. First, in this combined procedure there is no danger from any sort of manipulation in the anterior chamber. Second, at the conclusion of surgery, an appropriate size periphery iridectomy can be done after constricting pupil with inracameral pilocarpine following intraocular lens insertion. In this study, the authors also measured the pupillary diameter at different instances and made an interesting observation. After intracameral lidocaine injection, the average male pupil diameter was significantly larger at one, three, and five minutes, than the pupil size in females. Additionally, the average pupil diameter in blue iris group was significantly larger at one and three minutes than the brown iris group though there was no significant difference at five minutes. The authors have not explained the probable reason for the difference noticed. A typical reaction of individual iris tissue to a specific chemical structure,1 mechanical immobility caused by pigment granules in the iris,2 or greater accumulation of drug in larger extracellular spaces of heavily pigmented iris tissue3 might be some of the reasons for the difference in response of differentially pigmented irides. Some authors state that physiologically there is no difference between pupillary size of healthy males and females,4 while others state that females have larger pupils.5 On performing the MEDLINE search, we could not find literature on the reason for a difference in response of pupils of males and females to mydriatics. More research work to clarify this aspect is recommended.
2. 3. 4. 5.
AUTHOR REPLY WE APPRECIATE DR. SODHI AND ASSOCIATES COMMENTS
on our study. Dr Sohdi’s main concern centers on the use of lidocaine for phakic trabeculectomies. Specifically, the risk of cataract formation and peripheral iris crowding during intracameral lidocaine injection was raised. We would like to address these points. This study arose in the context of developing a satisfactory method of ocular anesthesia to replace peri- or retro-bulbar injection. At the time of this study, most surgeons we knew were using topical and intracameral anesthesia to perform cataract surgery. We noted that this combination provided excellent anesthesia, and wished to adapt it to trabeculectomy. As for pupil dilation, cataract surgeons were using preoperative mydriatics before surgery. When patients finally received the anesthetic in the operating room, they were already fully dilated. Any additional dilation from the anesthetic was not apparent. We were, therefore, surprised to discover the mydriatic effect when adapting this technique to trabeculectomy surgery. In the United States, most surgeons use a paracentesis in the anterior chamber to evaluate flow at the site of the trabeculectomy. We would like to take this opportunity to clarify that entry into the anterior chamber was with a sharp point blade and the lidocaine delivered with a 27-gauge cannula. The cannula was placed at the lip of the paracentesis and did not enter the anterior chamber. Therefore, there was no risk of an iatrogenic cataract from the intracameral lidocaine injection. In contrast to Dr. Sohdi’s method for trabeculectomy, we never use pilocarpine during a trabeculectomy since the goal is to move the lens diaphragm backward to deepen the anterior chamber. On occasion, dilation can pose a problem when performing the iridectomy. We then put intracameral miochol through the paracentesis to assure that the iridectomy is not excessively large. Since miochol is short lived, the pupil can then return to its normal diameter. At the end of the procedure, however, we commonly administer dilating drops and push the lens diaphragm posterior. Finally, Dr Sodhi and associates request an explanation of the difference in pupil diameter in the subsets of male vs
PUNITA KUMARI SODHI, MS, DNB LALIT VERMA, MD SIMMI K. RATAN, MCH
New Delhi, India
REFERENCES
1. Seidehamel RJ, Tye A, Patil PN. An analysis of ephedrine mydriasis in relationship to iris pigmentation in the guinea-pig
784
AMERICAN JOURNAL
eye in vitro. J Pharmacol Exp Therapeutics 1970;171:205– 213. Venable JP. Glaucoma in the Negro. J Nat Med Ass 1952;44: 7–14. Patil PN. Cocaine-binding by the pigmented and the nonpigmented iris and its relevance to the mydriatic effect. Invest Ophthalmol 1972;11:739 –746. Straub RH, Thies U, Kerp L. The pupillary light reflex. Age dependent and age-independent parameters in normal subjects. Ophthalmologica 1992;204:134 –142. Alexandridis E. Pupil size. In: The Pupil. Springer-Verlag. New York. 1982.
OF
OPHTHALMOLOGY
APRIL 2004