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No-anesthesia versus topical and topical plus intracameral anesthesia
LETTERS
References 1. Tsuneoka H, Shiba T, Takahashi Y. Ultrasonic phacoemulsification using a 1.4 mm incision: clinical results. J Cataract Refract Surg 2002; 28:81– 86 2. Agarwal A, Agarwal A, Agarwal S, et al. Phakonit: phacoemulsification through a 0.9 mm corneal incision. J Cataract Refract Surg 2001; 27:1548 –1552 3. Agarwal A, Agarwal A, Agarwal S, et al. Phakonit—lens removal through a 0.9 mm incision. (letter) J Cataract Refract Surg 2001; 27:1531–1532 4. Agarwal S, Agarwal A, Sachdev MS, et al. Air pump to prevent surge. In: Agarwal A, Agarwal A, Sachdev MS, et al, eds, Phacoemulsification, Laser Cataract Surgery and Foldable IOLs, 2nd ed. New Delhi, India, Jaypee Brothers 2000; 624 – 626 5. Boyd BF, Agarwal A, Agarwal A, Agarwal A. No anesthesia cataract surgery. Highlights Ophthalmol 2000; 451– 462
Reply: We appreciate the letter from Agarwal and coauthors in response to our article and are impressed by their achievement of a sub 1.0 mm incision with phakonit. Injecting air pressure into the infusion bottle to stabilize fluid flow is an excellent idea, and we did consider introducing that into our procedures in the past. That is, we have used gas–fluid exchange equipment (GFX, Alcon) and a vented gas forced infusion tube (VGFI tube, Alcon) to inject air into the infusion bottle with good results. However, we thought it was a little troublesome to use this equipment and tried to increase irrigation inflow volumes without external assistance. I would like to briefly explain how we solved the problem of destabilization of the anterior chamber during bimanual phaco surgery. Since the infusion cannula could also be used as a nucleofractis hook, we thought the outer diameter of the cannula should be thinner than 20 gauge. But a 20-gauge hypodermic needle, with an inner diameter of 0.6 mm, made it difficult to maintain a satisfactory infusion rate. With a 20gauge hypodermic needle, the flow rate did not exceed 38 mL/min even when the infusion bottle was elevated to 110 cm. So we tried to widen the inner diameter of the cannula to obtain the necessary infusion flow volume. We have developed a 20-gauge irrigating hook with an inner diameter of 0.75 mm. This irrigating hook is designed to effectively chop and divide the nucleus and also makes it possible to maintain a satisfactory flow volume of 50 mL/min when the infusion bottle is elevated to 110 cm. This irrigating hook is available from ASICO (Tsuneoka irrigating hook). With it, we have performed more than 700 cataract surgeries through ultrasmall incision ranging between 1.2 mm and 1.4 mm. In all cases, without any additional air pressure to the irrigation bottle, we were able to achieve sufficient irrigating inflow and safe surgery. I understand the antichamber collapser effectively stabilizes the anterior chamber during the bimanual phaco surgery when the special irrigating cannula is not used. Using this 1086
device, I believe we will be able to perform ultrasmall incision phaco surgery safely. We look forward to further exchange of information as we work to perfect ultrasmall incision phaco surgery and IOL implantation.—Hiroshi Tsuneoka, MD
No-Anesthesia Versus Topical and Topical Plus Intracameral Anesthesia andey et al.1 carried out a prospective randomized double-masked study in 75 patients who had clear corneal phacoemulsification with foldable IOL implantation. The patients were randomized to 1 of 3 groups of 25 patients each based on the type of anesthesia. Patients in Group 1 received drops of balanced salt solution before surgery; those in Group 2 received lidocaine 4% eyedrops preoperatively, and those in Group 3 received preoperative lidocaine 4% plus an intracameral injection of preservative-free lidocaine 1%. The authors did not find significantly different results among the 3 groups during surgery. However, patient discomfort and surgeon stress intraoperatively were significantly higher in the no-anesthesia group than in the topical and topical plus lidocaine groups. I believe these results are due to various factors, among them the surgeon’s skill and the excellent surgical technique performed through a clear corneal incision without the use of a forceps to stabilize the globe. The psychosomatic factor also plays an important role because an anxious patient may complain of pain even with topical anesthesia, which can raise the surgeon’s stress level. In February 1999, I began to perform cataract surgery similar to Agarwal’s method but using a new anesthesia technique2 in which cold is the analgesic agent (cryoanalgesia). Although the use of cold as an analgesic and antiinflammatory agent is well-known, if we add even minimal surgical trauma, the results in terms of pain are the same as when the surgery is performed without anesthesia. Other important factors that influence the sensation of pain are the patient’s race, eye color, age, and the anatomic and neurophysiological conditions of the cornea. In summary, I congratulate Pandey et al. for their interesting article.
P
FRANCISCO J. GUTIERREZ-CARMONA, MD, PHD Madrid, Spain
J CATARACT REFRACT SURG—VOL 28, JULY 2002
LETTERS
References
References
1. Pandey SK, Werner L, Apple DJ, et al. No-anesthesia clear corneal phacoemulsification versus topical and topical plus intracameral anesthesia: randomized clinical trial. J Cataract Refract Surg 2001; 27:1643–1650 2. Gutierrez-Carmona FJ. Phacoemulsification with cryoanalgesia: a new approach for cataract surgery. In: Agarwal S, Agarwal A, Apple DJ, et al, eds, Textbook of Ophthalmology, vol 2. New Delhi, India, Jaypee Brothers, 2002; 1770 –1772
1. Ram J, Pandey SK. Anesthesia for cataract surgery. In: Dutta LC, Modern Ophthalmology. New Delhi, India, Jaypee Brothers, 2000; 325–330 2. Dutton JJ, Hasan SA, Edelhauser HF, et al. Anesthesia for intraocular surgery. Surv Ophthalmol 2001; 46:172–184 3. Fichman RA. Use of topical anesthesia alone in cataract surgery. J Cataract Refract Surg 1996; 22:612– 614 4. Gills JP, Cherchio M, Raanan MG. Unpreserved lidocaine to control discomfort during cataract surgery using topical anesthesia. J Cataract Refract Surg 1997; 23:545–550 5. Leaming DV. Practice styles and preferences of ASCRS members—2000 survey. J Cataract Refract Surg 2001; 27:948 –955 6. Agarwal A, Agarwal A, Agarwal S. No anesthesia cataract surgery with karate chop. In: Agarwal S, Agarwal A, Sachdev MS, et al, eds, Phacoemulsification, Laser Cataract Surgery and Foldable IOLs. New Delhi, India, Jaypee Brothers, 1998; 145–153 7. Gutierrez-Carmona FJ. Phacoemulsification with cryoanalgesia: a new approach for cataract surgery. In: Agarwal S, Agarwal A, Apple DJ, et al, eds, Textbook of Ophthalmology, vol 2. New Delhi, India, Jaypee Brothers, 2002; 1770 –1772
Reply: We thank Dr. Gutierrez-Carmona for his interest and thoughtful comments about our study comparing noanesthesia, topical, and topical plus intracameral anesthesia. The use of topical anesthesia with cocaine for cataract extraction was first described in the United States by Knapp and in Germany by Carl Coller in 1884. Topical cocaine anesthesia, supplemented by subconjunctival anesthesia, remained the preferred method of pain control during cataract extraction until the 1930s, at which time retrobulbar and peribulbar regional blocks became the principal means of anesthesia.1,2 In 1992, Fichman introduced the use of topical anesthesia in modern cataract surgery; subsequently, Gills reported the use of intracameral lidocaine in conjunction with topical anesthesia.3,4 Topical anesthesia is the preferred technique for cataract surgeons in the United States according to a survey conducted by Leaming.5 However, recent advances in the development of sutureless, clear corneal, and small- or ultrasmall-incision phacoemulsification surgery (e.g., phakonit) and improved instrumentation have permitted more efficient and rapid nuclear fragmentation and removal, decreasing surgical times and intraocular tissue manipulation. The less invasive nature of modern clear corneal cataract surgery combined with better surgical skills has led to the performance of cataract surgery without pharmacological anesthesia. These alternative techniques include no-anesthesia and cryoanalgesia, proposed by Drs. Agarwal and Gutierrez-Carmona in 1998 and 1999, respectively.6,7 One of us (A.A.) has performed more than 5000 cases using the former technique. We commend Dr. Gutierrez-Carmona for proposing cryoanalgesia in cataract surgery. The use of a cooled eye pad, irrigating solution, and viscoelastic agents (cryoanalgesia) may help reduce patient pain and discomfort during cataract surgery. In our article, we proposed some hypotheses for noanesthesia cataract surgery based on surgico-anatomical and racial factors. However, the performance of no-anesthesia cataract surgery and cryoanalgesia in other parts of the world suggest that more research is needed to better understand the corneal sensations, innervation, neuroantaomy, and neurophysiology.— Suresh K. Pandey, MD, Amar Agarwal, MS, FRCS, FRCOphth
Reproducibility of the IOLMaster he article by Vogel and coauthors1 reports the results of a study that evaluates the repeatability of measurements with the IOLMaster (Zeiss). This is an interesting report that provides intraobserver and interobserver results. We agree with the conclusion that the IOLMaster is less investigator-dependent than echography. We have, unfortunately, noticed an incorrect interpretation of the results in the discussion section. The authors conclude that the IOLMaster’s accuracy is about 20 m. This is an underestimation since the worst standard deviation is 33.4 m. To determine the repeatability, they repeated measurements 20 times. The coherence length of the source being 150 m, the best resolution that can be obtained is 150 m. Hence, 150 m the accuracy they have obtained is ⫽33.5m. 冑20 This result is more consistent with the experimental standard deviations. The selectivity of partial coherence interferometry is based on the ability of the back-scattered signal to interfere with the reference signal. The resolution of such a
T
J CATARACT REFRACT SURG—VOL 28, JULY 2002
1087
References 1. Tsuneoka H, Shiba T, Takahashi Y. Ultrasonic phacoemulsification using a 1.4 mm incision: clinical results. J Cataract Refract Surg 2002; 28:81– 86 2. Agarwal A, Agarwal A, Agarwal S, et al. Phakonit: phacoemulsification through a 0.9 mm corneal incision. J Cataract Refract Surg 2001; 27:1548 –1552 3. Agarwal A, Agarwal A, Agarwal S, et al. Phakonit—lens removal through a 0.9 mm incision. (letter) J Cataract Refract Surg 2001; 27:1531–1532 4. Agarwal S, Agarwal A, Sachdev MS, et al. Air pump to prevent surge. In: Agarwal A, Agarwal A, Sachdev MS, et al, eds, Phacoemulsification, Laser Cataract Surgery and Foldable IOLs, 2nd ed. New Delhi, India, Jaypee Brothers 2000; 624 – 626 5. Boyd BF, Agarwal A, Agarwal A, Agarwal A. No anesthesia cataract surgery. Highlights Ophthalmol 2000; 451– 462
Reply: We appreciate the letter from Agarwal and coauthors in response to our article and are impressed by their achievement of a sub 1.0 mm incision with phakonit. Injecting air pressure into the infusion bottle to stabilize fluid flow is an excellent idea, and we did consider introducing that into our procedures in the past. That is, we have used gas–fluid exchange equipment (GFX, Alcon) and a vented gas forced infusion tube (VGFI tube, Alcon) to inject air into the infusion bottle with good results. However, we thought it was a little troublesome to use this equipment and tried to increase irrigation inflow volumes without external assistance. I would like to briefly explain how we solved the problem of destabilization of the anterior chamber during bimanual phaco surgery. Since the infusion cannula could also be used as a nucleofractis hook, we thought the outer diameter of the cannula should be thinner than 20 gauge. But a 20-gauge hypodermic needle, with an inner diameter of 0.6 mm, made it difficult to maintain a satisfactory infusion rate. With a 20gauge hypodermic needle, the flow rate did not exceed 38 mL/min even when the infusion bottle was elevated to 110 cm. So we tried to widen the inner diameter of the cannula to obtain the necessary infusion flow volume. We have developed a 20-gauge irrigating hook with an inner diameter of 0.75 mm. This irrigating hook is designed to effectively chop and divide the nucleus and also makes it possible to maintain a satisfactory flow volume of 50 mL/min when the infusion bottle is elevated to 110 cm. This irrigating hook is available from ASICO (Tsuneoka irrigating hook). With it, we have performed more than 700 cataract surgeries through ultrasmall incision ranging between 1.2 mm and 1.4 mm. In all cases, without any additional air pressure to the irrigation bottle, we were able to achieve sufficient irrigating inflow and safe surgery. I understand the antichamber collapser effectively stabilizes the anterior chamber during the bimanual phaco surgery when the special irrigating cannula is not used. Using this 1086
device, I believe we will be able to perform ultrasmall incision phaco surgery safely. We look forward to further exchange of information as we work to perfect ultrasmall incision phaco surgery and IOL implantation.—Hiroshi Tsuneoka, MD
No-Anesthesia Versus Topical and Topical Plus Intracameral Anesthesia andey et al.1 carried out a prospective randomized double-masked study in 75 patients who had clear corneal phacoemulsification with foldable IOL implantation. The patients were randomized to 1 of 3 groups of 25 patients each based on the type of anesthesia. Patients in Group 1 received drops of balanced salt solution before surgery; those in Group 2 received lidocaine 4% eyedrops preoperatively, and those in Group 3 received preoperative lidocaine 4% plus an intracameral injection of preservative-free lidocaine 1%. The authors did not find significantly different results among the 3 groups during surgery. However, patient discomfort and surgeon stress intraoperatively were significantly higher in the no-anesthesia group than in the topical and topical plus lidocaine groups. I believe these results are due to various factors, among them the surgeon’s skill and the excellent surgical technique performed through a clear corneal incision without the use of a forceps to stabilize the globe. The psychosomatic factor also plays an important role because an anxious patient may complain of pain even with topical anesthesia, which can raise the surgeon’s stress level. In February 1999, I began to perform cataract surgery similar to Agarwal’s method but using a new anesthesia technique2 in which cold is the analgesic agent (cryoanalgesia). Although the use of cold as an analgesic and antiinflammatory agent is well-known, if we add even minimal surgical trauma, the results in terms of pain are the same as when the surgery is performed without anesthesia. Other important factors that influence the sensation of pain are the patient’s race, eye color, age, and the anatomic and neurophysiological conditions of the cornea. In summary, I congratulate Pandey et al. for their interesting article.
P
FRANCISCO J. GUTIERREZ-CARMONA, MD, PHD Madrid, Spain
J CATARACT REFRACT SURG—VOL 28, JULY 2002
LETTERS
References
References
1. Pandey SK, Werner L, Apple DJ, et al. No-anesthesia clear corneal phacoemulsification versus topical and topical plus intracameral anesthesia: randomized clinical trial. J Cataract Refract Surg 2001; 27:1643–1650 2. Gutierrez-Carmona FJ. Phacoemulsification with cryoanalgesia: a new approach for cataract surgery. In: Agarwal S, Agarwal A, Apple DJ, et al, eds, Textbook of Ophthalmology, vol 2. New Delhi, India, Jaypee Brothers, 2002; 1770 –1772
1. Ram J, Pandey SK. Anesthesia for cataract surgery. In: Dutta LC, Modern Ophthalmology. New Delhi, India, Jaypee Brothers, 2000; 325–330 2. Dutton JJ, Hasan SA, Edelhauser HF, et al. Anesthesia for intraocular surgery. Surv Ophthalmol 2001; 46:172–184 3. Fichman RA. Use of topical anesthesia alone in cataract surgery. J Cataract Refract Surg 1996; 22:612– 614 4. Gills JP, Cherchio M, Raanan MG. Unpreserved lidocaine to control discomfort during cataract surgery using topical anesthesia. J Cataract Refract Surg 1997; 23:545–550 5. Leaming DV. Practice styles and preferences of ASCRS members—2000 survey. J Cataract Refract Surg 2001; 27:948 –955 6. Agarwal A, Agarwal A, Agarwal S. No anesthesia cataract surgery with karate chop. In: Agarwal S, Agarwal A, Sachdev MS, et al, eds, Phacoemulsification, Laser Cataract Surgery and Foldable IOLs. New Delhi, India, Jaypee Brothers, 1998; 145–153 7. Gutierrez-Carmona FJ. Phacoemulsification with cryoanalgesia: a new approach for cataract surgery. In: Agarwal S, Agarwal A, Apple DJ, et al, eds, Textbook of Ophthalmology, vol 2. New Delhi, India, Jaypee Brothers, 2002; 1770 –1772
Reply: We thank Dr. Gutierrez-Carmona for his interest and thoughtful comments about our study comparing noanesthesia, topical, and topical plus intracameral anesthesia. The use of topical anesthesia with cocaine for cataract extraction was first described in the United States by Knapp and in Germany by Carl Coller in 1884. Topical cocaine anesthesia, supplemented by subconjunctival anesthesia, remained the preferred method of pain control during cataract extraction until the 1930s, at which time retrobulbar and peribulbar regional blocks became the principal means of anesthesia.1,2 In 1992, Fichman introduced the use of topical anesthesia in modern cataract surgery; subsequently, Gills reported the use of intracameral lidocaine in conjunction with topical anesthesia.3,4 Topical anesthesia is the preferred technique for cataract surgeons in the United States according to a survey conducted by Leaming.5 However, recent advances in the development of sutureless, clear corneal, and small- or ultrasmall-incision phacoemulsification surgery (e.g., phakonit) and improved instrumentation have permitted more efficient and rapid nuclear fragmentation and removal, decreasing surgical times and intraocular tissue manipulation. The less invasive nature of modern clear corneal cataract surgery combined with better surgical skills has led to the performance of cataract surgery without pharmacological anesthesia. These alternative techniques include no-anesthesia and cryoanalgesia, proposed by Drs. Agarwal and Gutierrez-Carmona in 1998 and 1999, respectively.6,7 One of us (A.A.) has performed more than 5000 cases using the former technique. We commend Dr. Gutierrez-Carmona for proposing cryoanalgesia in cataract surgery. The use of a cooled eye pad, irrigating solution, and viscoelastic agents (cryoanalgesia) may help reduce patient pain and discomfort during cataract surgery. In our article, we proposed some hypotheses for noanesthesia cataract surgery based on surgico-anatomical and racial factors. However, the performance of no-anesthesia cataract surgery and cryoanalgesia in other parts of the world suggest that more research is needed to better understand the corneal sensations, innervation, neuroantaomy, and neurophysiology.— Suresh K. Pandey, MD, Amar Agarwal, MS, FRCS, FRCOphth
Reproducibility of the IOLMaster he article by Vogel and coauthors1 reports the results of a study that evaluates the repeatability of measurements with the IOLMaster (Zeiss). This is an interesting report that provides intraobserver and interobserver results. We agree with the conclusion that the IOLMaster is less investigator-dependent than echography. We have, unfortunately, noticed an incorrect interpretation of the results in the discussion section. The authors conclude that the IOLMaster’s accuracy is about 20 m. This is an underestimation since the worst standard deviation is 33.4 m. To determine the repeatability, they repeated measurements 20 times. The coherence length of the source being 150 m, the best resolution that can be obtained is 150 m. Hence, 150 m the accuracy they have obtained is ⫽33.5m. 冑20 This result is more consistent with the experimental standard deviations. The selectivity of partial coherence interferometry is based on the ability of the back-scattered signal to interfere with the reference signal. The resolution of such a
T
J CATARACT REFRACT SURG—VOL 28, JULY 2002
1087