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Lid Speculum for Surgery Without Lid Block
LETTERS
riorly, the center of the anterior capsule is aspirated into the cutting port to create an initial opening. Any nuclear or cortical material that spontaneously exits the capsular bag anteriorly is easily aspirated without interrupting the capsulectomy technique. The capsular opening is en larged using the cutter in a gentle circular fashion. The cutter is kept just anterior to the capsular edge, aspirat ing the capsule up into the cutting port rather than engaging the capsular edge directly. Anterior chamber volume is maintained through a separate paracentesis site. Significant lens hydration, therefore, does not oc cur. Visualization of the capsular edge during enlarge ment of the capsulectomy is excellent because the aspirating capability of the vitrector continuously re moves lens cortex as it enters the anterior chamber. A smooth, round capsulectomy is produced that resists radial tearing. Drs. Gimbel and Basti contend that theoretically, man ual anterior capsulorhexis should be easier in the live clin ical setting than in the ex vivo setting used in our study. However, having performed manual capsulorhexis in very young eyes under both conditions, I have found doing manual continuous curvilinear capsulorhexis (eeG) in very young eyes using the open-sky laboratory model to be much easier than performing this technique in actual clin ical practice. Manual eee remains the gold standard for producing a smooth capsular edge that resists radial tearing. For surgeons who have no difficulty performing manual eee in very young eyes, we would advise them to continue. How ever, we have communicated with many surgeons experi enced in adult eee who have been humbled by a drastically reduced success rate in very young eyes. The prospective, randomized clinical trial Drs. Gimbel and Basti suggest is not feasible because the success rate using these techniques would be surgeon dependent. Mechanized circular capsulectomy is offered as an alternative for surgeons who have difficulty manually tear ing young, very elastic anterior capsules. As the minimum age for IOL implantation continues to be lowered, I believe this technique will become more and more important. I currently perform a mechanized anterior capsulectomy, lens aspiration, IOL placement into the capsular bag, and primary pars plana posterior capsulectomy in children younger than 8 years. In older children, I perform a stan dard manual eee and leave the posterior capsule intact. We again thank Drs. Gimbel and Basti for their letter and for their interest in our work.- M. Edward Wilson, MD
Reference 1. Wilson ME, Saunders RA, Roberts EL, Apple DJ. Mechanized anterior capsulectomy as an alternative to manual capsulorhexis in children undergoing intraocular lens implantation. In press, J Pediatr Ophthalmol Strabismus
4
Perilimbal Anesthesia
R
egarding the article by Pallan and coauthors,l the perilimbal injection of lidocaine under direct visu alization no doubt eliminates many risks associated with other forms of sharp-needle anesthetic delivery. The au thors, however, are mistaken when, in reference to Fukasaku's "pinpoint anesthesia" technique of infusing lidocaine into the posterior sub-Tenon's space, they state that a "cannula in [this approach] presents a risk of ocular penetration." The various reusable cannulas for delivery of sub-T en on's anesthesia, such as the Stevens, Fukasaku, Masket, and a prototype cannula of mine, were specifically designed with blind passage in mind and are for this reason blunt. The risk of ocular penetration or any other complication relating to a sharp point is therefore eliminated. These same blunt cannulas can safely deliver "non-depo" corticosteroids and/or antibiotics into the posterior sub-Tenon's space at the completion of the case. WILLIAM
L.
CORBIN,
MD
Los Angeles, California Reference 1. Pallan LA, Kondrot EC, Stout RR. Sutureless scleral tunnel cataract surgery using topical and low dose perilimbal anesthe sia. J Cataract Refract Surg 1995; 21:504-507
Lid Speculum for Surgery Without Lid Block
"\VJith the wider acceptance and success of phaco W emulsification and small incision cataract sur gery, many surgeons are using minimal ocular anesthesia techniques such as topical and subconjunctival, often without the use of lid blocks. There are potential prob lems with either no or inadequate lid block, especially in eyes with strong orbicularis action (squeezers). These patients may be able to squeeze hard enough to compress the popular Kratz Barraquer or other flexible wire specu lum during their surgery, raising vitreal pressure and thus shallowing the anterior chamber. fu a consequence, the surgery is a much more difficult and potentially haz ardous procedure, with increased risk of endothelial cell damage or capsular rupture.
J CATARACT REFRACT SURG-VOL 22, JANUARY/FEBRUARY 1996
LEITERS
The problem of an overacting orbicularis (squeez ing) is especially prone to occur in patients receiving less invasive anesthesia, such as topical or subconjunctival, because these techniques have minimal effect on lid movement. In contrast, high-volume peri bulbar or ret robulbar anesthesia often gives some degree of eyelid akinesia by gradually infiltrating into periocular orbicu laris muscle. In addition, with topical anesthesia, pa tients may squeeze their eyelids if they feel discomfort during the procedure. One potential solution is to routinely or selectively administer lid blocks. Unfortunately, lid blocks must be given by an experienced ophthalmologist or anesthetist, resulting in loss of efficiency (time) or additional ex pense. Furthermore, lid block injections tend to be pain ful because of the sensitivity of facial skin. Finally, poor postoperative lid function resulting from the block might require patching the eye. Recently, I have had good results using the Cas troviejo speculum (Fishkind Castroviejo, KI-5702, Kat ena) for phacoemulsification extracapsular cataract surgery and topical and/or subconjunctival anesthesia without lid blocks. The Castroviejo speculum is modi fied to make it open by removing the superior and infe rior cross bars. This open design is similar to the Kratz Barraquer, which allows better access of the phacoemul sification tip to the superior scleral tunnel incision. The metal frame of the modified Castroviejo speculum is much heavier than the wire design Kratz Barraquer, making it less prone to compression by the eyelids (Fig ure 1). In addition, the Castroviejo speculum has an
Figure 1. (Anderson) The modified Castroviejo speculum (top) is less prone to compression than the wire Kratz Barraquer specu lum (bottom).
adjustable mechanism (screw) on the end that solidly holds the speculum open, allowing for a variable and wide palbebral fissure to improve surgical exposure. The speculum enables the surgeon to operate on almost all topical and subconjunctival anesthesia cases without lid blocks. The speculum can also be used on radial keratot omy patients who have topical anesthesia.
c. JOSEPH ANDERSON, MD Madison, Wisconsin
Measuring Structures Within the Eye
A
bout 2 years ago, one of us (A.R:V.) visited the Gimbel Eye Centre in Calgary, Canada, and saw a capsulorhexis being measured on a television screen. Since then, we have standardized the method and re fined it to suit various study projects being carried out at our eye clinic, which has a high volume of cataract surgery. Because of corneal magnification, measurement of structures inside the eye is not accurate. 1 Various direct and indirect methods have been used to deter mine pupil size, IOL decentration, and so on. 2 - 4 Our version of the Gimbel technique is a simple way to document measurements, both intraoperatively and postoperatively. In this method, the capsulorhexis and the pupil are seen on a flat 51 cm television screen. They are measured in centimeters with a transparent ruler. The microscope magnification is kept at X 10. We pre pared a conversion table, which is pasted on the op erating room wall (Table O. The table converts the measurements in centimeters to the actual size in millimeters. To devise the conversion table, we took two sim ilar transparent rulers, one focused under the micro scope with XI 0 magnification. The distance between the millimeter markings seen magnified on the tele vision screen was measured with another ruler in cen timeters. For example, 3.0 mm measured 6.9 cm on the screen, and 5.0 mm measured 11.3 cm. The error caused by corneal magnification was corrected using an object of known size. In this case, it was a 5.25 mm intraocular lens (IOL). We measured the IOL on the screen in 10 patients after implantation. It measured
J CATARACT REFRACT SURG-VOL 22. JANUARY/FEBRUARY 1996
5
riorly, the center of the anterior capsule is aspirated into the cutting port to create an initial opening. Any nuclear or cortical material that spontaneously exits the capsular bag anteriorly is easily aspirated without interrupting the capsulectomy technique. The capsular opening is en larged using the cutter in a gentle circular fashion. The cutter is kept just anterior to the capsular edge, aspirat ing the capsule up into the cutting port rather than engaging the capsular edge directly. Anterior chamber volume is maintained through a separate paracentesis site. Significant lens hydration, therefore, does not oc cur. Visualization of the capsular edge during enlarge ment of the capsulectomy is excellent because the aspirating capability of the vitrector continuously re moves lens cortex as it enters the anterior chamber. A smooth, round capsulectomy is produced that resists radial tearing. Drs. Gimbel and Basti contend that theoretically, man ual anterior capsulorhexis should be easier in the live clin ical setting than in the ex vivo setting used in our study. However, having performed manual capsulorhexis in very young eyes under both conditions, I have found doing manual continuous curvilinear capsulorhexis (eeG) in very young eyes using the open-sky laboratory model to be much easier than performing this technique in actual clin ical practice. Manual eee remains the gold standard for producing a smooth capsular edge that resists radial tearing. For surgeons who have no difficulty performing manual eee in very young eyes, we would advise them to continue. How ever, we have communicated with many surgeons experi enced in adult eee who have been humbled by a drastically reduced success rate in very young eyes. The prospective, randomized clinical trial Drs. Gimbel and Basti suggest is not feasible because the success rate using these techniques would be surgeon dependent. Mechanized circular capsulectomy is offered as an alternative for surgeons who have difficulty manually tear ing young, very elastic anterior capsules. As the minimum age for IOL implantation continues to be lowered, I believe this technique will become more and more important. I currently perform a mechanized anterior capsulectomy, lens aspiration, IOL placement into the capsular bag, and primary pars plana posterior capsulectomy in children younger than 8 years. In older children, I perform a stan dard manual eee and leave the posterior capsule intact. We again thank Drs. Gimbel and Basti for their letter and for their interest in our work.- M. Edward Wilson, MD
Reference 1. Wilson ME, Saunders RA, Roberts EL, Apple DJ. Mechanized anterior capsulectomy as an alternative to manual capsulorhexis in children undergoing intraocular lens implantation. In press, J Pediatr Ophthalmol Strabismus
4
Perilimbal Anesthesia
R
egarding the article by Pallan and coauthors,l the perilimbal injection of lidocaine under direct visu alization no doubt eliminates many risks associated with other forms of sharp-needle anesthetic delivery. The au thors, however, are mistaken when, in reference to Fukasaku's "pinpoint anesthesia" technique of infusing lidocaine into the posterior sub-Tenon's space, they state that a "cannula in [this approach] presents a risk of ocular penetration." The various reusable cannulas for delivery of sub-T en on's anesthesia, such as the Stevens, Fukasaku, Masket, and a prototype cannula of mine, were specifically designed with blind passage in mind and are for this reason blunt. The risk of ocular penetration or any other complication relating to a sharp point is therefore eliminated. These same blunt cannulas can safely deliver "non-depo" corticosteroids and/or antibiotics into the posterior sub-Tenon's space at the completion of the case. WILLIAM
L.
CORBIN,
MD
Los Angeles, California Reference 1. Pallan LA, Kondrot EC, Stout RR. Sutureless scleral tunnel cataract surgery using topical and low dose perilimbal anesthe sia. J Cataract Refract Surg 1995; 21:504-507
Lid Speculum for Surgery Without Lid Block
"\VJith the wider acceptance and success of phaco W emulsification and small incision cataract sur gery, many surgeons are using minimal ocular anesthesia techniques such as topical and subconjunctival, often without the use of lid blocks. There are potential prob lems with either no or inadequate lid block, especially in eyes with strong orbicularis action (squeezers). These patients may be able to squeeze hard enough to compress the popular Kratz Barraquer or other flexible wire specu lum during their surgery, raising vitreal pressure and thus shallowing the anterior chamber. fu a consequence, the surgery is a much more difficult and potentially haz ardous procedure, with increased risk of endothelial cell damage or capsular rupture.
J CATARACT REFRACT SURG-VOL 22, JANUARY/FEBRUARY 1996
LEITERS
The problem of an overacting orbicularis (squeez ing) is especially prone to occur in patients receiving less invasive anesthesia, such as topical or subconjunctival, because these techniques have minimal effect on lid movement. In contrast, high-volume peri bulbar or ret robulbar anesthesia often gives some degree of eyelid akinesia by gradually infiltrating into periocular orbicu laris muscle. In addition, with topical anesthesia, pa tients may squeeze their eyelids if they feel discomfort during the procedure. One potential solution is to routinely or selectively administer lid blocks. Unfortunately, lid blocks must be given by an experienced ophthalmologist or anesthetist, resulting in loss of efficiency (time) or additional ex pense. Furthermore, lid block injections tend to be pain ful because of the sensitivity of facial skin. Finally, poor postoperative lid function resulting from the block might require patching the eye. Recently, I have had good results using the Cas troviejo speculum (Fishkind Castroviejo, KI-5702, Kat ena) for phacoemulsification extracapsular cataract surgery and topical and/or subconjunctival anesthesia without lid blocks. The Castroviejo speculum is modi fied to make it open by removing the superior and infe rior cross bars. This open design is similar to the Kratz Barraquer, which allows better access of the phacoemul sification tip to the superior scleral tunnel incision. The metal frame of the modified Castroviejo speculum is much heavier than the wire design Kratz Barraquer, making it less prone to compression by the eyelids (Fig ure 1). In addition, the Castroviejo speculum has an
Figure 1. (Anderson) The modified Castroviejo speculum (top) is less prone to compression than the wire Kratz Barraquer specu lum (bottom).
adjustable mechanism (screw) on the end that solidly holds the speculum open, allowing for a variable and wide palbebral fissure to improve surgical exposure. The speculum enables the surgeon to operate on almost all topical and subconjunctival anesthesia cases without lid blocks. The speculum can also be used on radial keratot omy patients who have topical anesthesia.
c. JOSEPH ANDERSON, MD Madison, Wisconsin
Measuring Structures Within the Eye
A
bout 2 years ago, one of us (A.R:V.) visited the Gimbel Eye Centre in Calgary, Canada, and saw a capsulorhexis being measured on a television screen. Since then, we have standardized the method and re fined it to suit various study projects being carried out at our eye clinic, which has a high volume of cataract surgery. Because of corneal magnification, measurement of structures inside the eye is not accurate. 1 Various direct and indirect methods have been used to deter mine pupil size, IOL decentration, and so on. 2 - 4 Our version of the Gimbel technique is a simple way to document measurements, both intraoperatively and postoperatively. In this method, the capsulorhexis and the pupil are seen on a flat 51 cm television screen. They are measured in centimeters with a transparent ruler. The microscope magnification is kept at X 10. We pre pared a conversion table, which is pasted on the op erating room wall (Table O. The table converts the measurements in centimeters to the actual size in millimeters. To devise the conversion table, we took two sim ilar transparent rulers, one focused under the micro scope with XI 0 magnification. The distance between the millimeter markings seen magnified on the tele vision screen was measured with another ruler in cen timeters. For example, 3.0 mm measured 6.9 cm on the screen, and 5.0 mm measured 11.3 cm. The error caused by corneal magnification was corrected using an object of known size. In this case, it was a 5.25 mm intraocular lens (IOL). We measured the IOL on the screen in 10 patients after implantation. It measured
J CATARACT REFRACT SURG-VOL 22. JANUARY/FEBRUARY 1996
5