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The lens and angle-closure glaucoma
letters Sedation for Cataract Surgery e read with interest the paper by Harman1 regarding combined sedation and topical anesthesia for cataract surgery. Although not conclusive, the paper raises timely issues that deserve wider discussion. Sedation for cataract surgery is a complex issue because of the predominantly elderly population. The ideal sedation technique should be easily administered, reliably achieve a clinically useful but not excessive plane of sedation, and be easily reversible, with a quick recovery profile. As most patients are discharged within a few hours of surgery, long-acting benzodiazepines (eg, lorazepam) may not be suitable for use in the elderly. Midazolam, with its shorter half-life of 2 hours, would be ideal for sedation, but the oral route of administration is subjected to first-pass metabolism, hence lower bioavailability. In a pilot study, Hodgson et al.2 used nebulized intranasal administration of 0.4 mg/kg of midazolam to produce clinically appropriate sedation in adults within 10 minutes. It had high patient acceptance and no adverse effects. However, we believe that the volume required to sedate adults makes the intranasal route impractical for clinical use. The role of propofol as a controlled intraoperative sedative has to be investigated fully. When used in appropriate infusion rates, it has been shown to be safe and effective because of its favorable pharmacological properties.3 Worldwide, most cataract patients still have regional anesthesia by peribulbar or sub-Tenon’s routes and midazolam sedation should be regarded as adjunctive. Ultimately, we all strive for the safest procedure with the maximum convenience for the patient and the minimum inconvenience to the surgeon.
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SHAHZAD SHAFQUAT, FCPS, FRCS SRINIVASAN DHILEEPAN, FRCA CHRIS CHILD, MBBS SIMON HORGAN, FRCS, FRCOPHTH Kingston Upon Thames, United Kingdom References 1. Harman DM. Combined sedation and topical anesthesia for cataract surgery. J Cataract Refract Surg 2000; 26:109 –113 © 2001 ASCRS and ESCRS Published by Elsevier Science Inc.
2. Hodgson PE, et al. Administration of nebulised intranasal midazolam to healthy adult volunteers. Br J Anaesth 1994; 73:719 3. Osbourne GA, et al. Intraoperative patient controlled sedation. Anaesthesia 1991; 46:553–556
The Lens and Angle-Closure Glaucoma congratulate the journal on the timely editorial1 and the article by Roberts et al.2 in the same issue advocating phacoemulsification in eyes with nonresponsive treatment of primary angle-closure glaucoma (PACG) attack. During the mid-1950s, I was a resident surgical registrar at Moorfields Eye Hospital in London. During my residency, we had a case of acute PACG that did not respond to medical treatment and a basal peripheral iridectomy; the intraocular pressure (IOP) remained very high. After much thought, 1 of the eye consultant surgeons removed the clear crystalline lens (intracapsular lens extraction as it was before the days of extracapsular cataract extraction [ECCE] and intraocular lens [IOL] implantation and also phacoemulsification). To everyone’s amazement, the patient’s eye settled down, the IOP returned to within normal limits, and the corrected visual acuity improved to 6/12 with glasses. Such cases of acute PACG that did not respond to medical treatment and peripheral iridectomy came to be termed malignant glaucoma, and removal of the crystalline lens as the correct treatment was established. I agree with Roberts et al. who advocate phacoemulsification with IOL implantation as the treatment of choice now. May I suggest that in countries that do not have the facility of phacoemulsification, a standard ECCE with IOL implantation would be an equally justifiable procedure, even in remote parts of the country. Primary angle-closure glaucoma is well recognized now among the Chinese population in the East who are myopic and also prone to acute PACG attack. A paper on this subject was read at the International Congress of Ophthalmology in 1990 in Singapore, where I suggested that although myopic eyes are usually large, the possibility of the iris–lens diaphragm moving forward
I
LETTERS
exists with an increase in the size of the crystalline lens, precipitating an acute attack of PACG. S.B. KAPUR, FRCS, FRCOPHTH London, United Kingdom References 1. Obstbaum SA. The lens and angle-closure glaucoma (editorial). J Cataract Refract Surg 2000; 26:941–942 2. Roberts TV, Francis IC, Lertusumitkul S, et al. Primary phacoemulsification for uncontrolled angle-closure glaucoma. J Cataract Refract Surg 2000; 26:1012–1016
Intraoperative Peripheral Anterior Capsulotomy to Prevent Early Postoperative Capsular Block Syndrome
Figure 2. (Yepez) A permeable inferior anterior capsulotomy is shown beyond the edge of the IOL.
e are delighted with the increasing interest in capsular block syndrome (CBS), as reflected in several recent articles.1–3 The authors are to be commended for providing very useful information regarding CBS after phacoemulsification and intraocular lens (IOL) implantation in the presence of an anterior continuous curvilinear capsulorhexis (CCC). Theng and coauthors1 treated their CBS patients with an anterior or posterior neodymium:YAG (Nd: YAG) capsulotomy. However, an anterior Nd:YAG capsulotomy may expose the anterior chamber to an acute release of viscoelastic material, potentially elevating intraocular pressure. In addition, wide dilation of the pupil is necessary and inadvertent contact with the edge of the iris can result in hemorrhage or posterior synechia
formation.4 Furthermore, the incidence of rhegmatogenous retinal detachment is higher after a posterior Nd: YAG capsulotomy.5,6 The best treatment is prevention by complete removal of viscoelastic material after IOL insertion. Although CBS is uncommon (0.3% to 1.6%),4,7 we suggest a new surgical technique that we have called intraoperative peripheral anterior capsulotomy (IPAC) as an alternative to prevent early postoperative CBS. We have performed IPAC in 20 eyes during phacoemulsification and IOL implantation in the presence of a small anterior CCC (4.5 to 5.0 mm) where the risk of development of CBS was deemed to be high. After the foldable IOL was in place, an iris retractor was used through the paracentesis site to expose the anterior capsule at the 6 o’clock position and an inferior anterior capsulotomy was performed beyond the edge of the IOL using the 23 gauge fine tip of a wet-field hemostatic eraser (Mentor O & O Inc.) in all cases (Figures 1 and 2). We have followed our patients for a very short time (mean 4 months; range 2 to 6 months). However, no patient has developed CBS or any other complication. Our small series suggests that IPAC may be an alternative to prevent CBS in high-risk eyes, including those with a small anterior CCC or viscoelastic material trapped in the capsular bag. This new surgical technique is safe, effective, inexpensive, and easy to perform. However, longer follow-up is needed.
Figure 1. (Yepez) After the foldable IOL is in place, an iris retractor is used through the paracentesis site to expose the anterior capsule at the 6 o’clock position and an inferior anterior capsulotomy is performed beyond the edge of the IOL using the tip of a wet-field hemostatic eraser.
JUAN B. YEPEZ, MD JAZMIN CEDEN˜ O DE YEPEZ, MD Maracaibo, Venezuela
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J CATARACT REFRACT SURG—VOL 27, FEBRUARY 2001
J. FERNANDO AREVALO, MD Caracas, Venezuela 177
W
SHAHZAD SHAFQUAT, FCPS, FRCS SRINIVASAN DHILEEPAN, FRCA CHRIS CHILD, MBBS SIMON HORGAN, FRCS, FRCOPHTH Kingston Upon Thames, United Kingdom References 1. Harman DM. Combined sedation and topical anesthesia for cataract surgery. J Cataract Refract Surg 2000; 26:109 –113 © 2001 ASCRS and ESCRS Published by Elsevier Science Inc.
2. Hodgson PE, et al. Administration of nebulised intranasal midazolam to healthy adult volunteers. Br J Anaesth 1994; 73:719 3. Osbourne GA, et al. Intraoperative patient controlled sedation. Anaesthesia 1991; 46:553–556
The Lens and Angle-Closure Glaucoma congratulate the journal on the timely editorial1 and the article by Roberts et al.2 in the same issue advocating phacoemulsification in eyes with nonresponsive treatment of primary angle-closure glaucoma (PACG) attack. During the mid-1950s, I was a resident surgical registrar at Moorfields Eye Hospital in London. During my residency, we had a case of acute PACG that did not respond to medical treatment and a basal peripheral iridectomy; the intraocular pressure (IOP) remained very high. After much thought, 1 of the eye consultant surgeons removed the clear crystalline lens (intracapsular lens extraction as it was before the days of extracapsular cataract extraction [ECCE] and intraocular lens [IOL] implantation and also phacoemulsification). To everyone’s amazement, the patient’s eye settled down, the IOP returned to within normal limits, and the corrected visual acuity improved to 6/12 with glasses. Such cases of acute PACG that did not respond to medical treatment and peripheral iridectomy came to be termed malignant glaucoma, and removal of the crystalline lens as the correct treatment was established. I agree with Roberts et al. who advocate phacoemulsification with IOL implantation as the treatment of choice now. May I suggest that in countries that do not have the facility of phacoemulsification, a standard ECCE with IOL implantation would be an equally justifiable procedure, even in remote parts of the country. Primary angle-closure glaucoma is well recognized now among the Chinese population in the East who are myopic and also prone to acute PACG attack. A paper on this subject was read at the International Congress of Ophthalmology in 1990 in Singapore, where I suggested that although myopic eyes are usually large, the possibility of the iris–lens diaphragm moving forward
I
LETTERS
exists with an increase in the size of the crystalline lens, precipitating an acute attack of PACG. S.B. KAPUR, FRCS, FRCOPHTH London, United Kingdom References 1. Obstbaum SA. The lens and angle-closure glaucoma (editorial). J Cataract Refract Surg 2000; 26:941–942 2. Roberts TV, Francis IC, Lertusumitkul S, et al. Primary phacoemulsification for uncontrolled angle-closure glaucoma. J Cataract Refract Surg 2000; 26:1012–1016
Intraoperative Peripheral Anterior Capsulotomy to Prevent Early Postoperative Capsular Block Syndrome
Figure 2. (Yepez) A permeable inferior anterior capsulotomy is shown beyond the edge of the IOL.
e are delighted with the increasing interest in capsular block syndrome (CBS), as reflected in several recent articles.1–3 The authors are to be commended for providing very useful information regarding CBS after phacoemulsification and intraocular lens (IOL) implantation in the presence of an anterior continuous curvilinear capsulorhexis (CCC). Theng and coauthors1 treated their CBS patients with an anterior or posterior neodymium:YAG (Nd: YAG) capsulotomy. However, an anterior Nd:YAG capsulotomy may expose the anterior chamber to an acute release of viscoelastic material, potentially elevating intraocular pressure. In addition, wide dilation of the pupil is necessary and inadvertent contact with the edge of the iris can result in hemorrhage or posterior synechia
formation.4 Furthermore, the incidence of rhegmatogenous retinal detachment is higher after a posterior Nd: YAG capsulotomy.5,6 The best treatment is prevention by complete removal of viscoelastic material after IOL insertion. Although CBS is uncommon (0.3% to 1.6%),4,7 we suggest a new surgical technique that we have called intraoperative peripheral anterior capsulotomy (IPAC) as an alternative to prevent early postoperative CBS. We have performed IPAC in 20 eyes during phacoemulsification and IOL implantation in the presence of a small anterior CCC (4.5 to 5.0 mm) where the risk of development of CBS was deemed to be high. After the foldable IOL was in place, an iris retractor was used through the paracentesis site to expose the anterior capsule at the 6 o’clock position and an inferior anterior capsulotomy was performed beyond the edge of the IOL using the 23 gauge fine tip of a wet-field hemostatic eraser (Mentor O & O Inc.) in all cases (Figures 1 and 2). We have followed our patients for a very short time (mean 4 months; range 2 to 6 months). However, no patient has developed CBS or any other complication. Our small series suggests that IPAC may be an alternative to prevent CBS in high-risk eyes, including those with a small anterior CCC or viscoelastic material trapped in the capsular bag. This new surgical technique is safe, effective, inexpensive, and easy to perform. However, longer follow-up is needed.
Figure 1. (Yepez) After the foldable IOL is in place, an iris retractor is used through the paracentesis site to expose the anterior capsule at the 6 o’clock position and an inferior anterior capsulotomy is performed beyond the edge of the IOL using the tip of a wet-field hemostatic eraser.
JUAN B. YEPEZ, MD JAZMIN CEDEN˜ O DE YEPEZ, MD Maracaibo, Venezuela
W
J CATARACT REFRACT SURG—VOL 27, FEBRUARY 2001
J. FERNANDO AREVALO, MD Caracas, Venezuela 177