Vol. 110, No.5
Letters to the Journal
577
4. Forstot, S. 1., and Damiano, R. E.: Trauma after radial keratotomy. Ophthalmology 95:833, 1988. 5. Binder, P. S., Waring, G. 0., Arrowsmith, P. N., and Wang, c.: Histopathology of traumatic corneal rupture after radial keratotomy. Arch. Ophthalmol. 106:1584, 1988.
Translimbal Iris Hook for Pupillary Dilation During Vitreous Surgery Dwain G. Fuller, M.D., and Donald L. Wilson, M.D. Texas Retina Associates (D.G.F.) and Midwest Eye Institute (D.L.W.).
Inquiries to Dwain G. Fuller, M.D., 7150 Greenville Ave., Dallas, TX 75231.
A number of techniques have been described for achieving wide pupillary dilation to facilitate peripheral vitreoretinal procedures. During protracted surgery with vitreous base dissection, pharmacologic approaches, such as preoperative flurbiprofen or epinephrine in the infusion system, often fail to prevent miosis. Iris sphincterotomy and iridectomy can be used, but they are cosmetically objectionable and may cause bleeding. Mechanical stretching of the iris can be achieved with sutures-! or with a recently described intraocular tack." We devised a translimbal iris hook that we believe offers advantages over the use of intraocular sutures or tacks for iris stretching. The hook can be simply fashioned from a small length of 0.3-mm diameter stainless steel wire. A piece of solid silicone (cut from a silicone rod used for scleral buckling) is threaded onto the noncurved end of the wire to serve as a stop. A microvitreoretinal blade is used to enter the anterior chamber. The iris hook is passed into the anterior chamber through the limbal incision, and the pupillary margin is engaged. Partial withdrawal of the wire permits the desired state of dilation to be achieved. The distal end of the wire is then carefully grasped with a needle holder, and the silicone stop is snugged down to the corneosclerallimbus (Figure). The placement of one hook may be adequate if wide dilation is required in only one quadrant. At the conclusion of the surgery the hooks are removed, and the limbal entrance sites are each closed with a single 8-0 Vicry I suture. This device is well suited to aphakic and pseudophakic eyes and may be applicable to phakic eyes in selected cases. We have used this hook to retract the iris to permit successful extraction of a small foreign body lodged be-
Figure (Fuller and Wilson). The use of two translimbal iris hooks.
tween the inferior iris and the anterior lens capsule.
References 1. Eckardt, c.: Pupillary stretching. A new procedure in vitreous surgery. Retina 5:235, 1985. 2. Zivojnovic, R.: Silicone Oil in Vitreous Surgery. The Netherlands, Martinus Nijhoff Publishers, 1987, p.126. 3. McCuen, B. W., II, Hickingbotharn, D., Tsai, M., and de Juan, E., Jr.: Temporary iris fixation with a micro-iris retractor. Arch. Ophthalmol. 107:925, 1989.
A Sutureless Self-Retaining Infusion Cannula for Pars Plana Vitrectomy Genevieve Mason, R.N., J. Michael Sullivan, M.D., and R. Joseph Olk, M.D. Barnes Hospital (G.M., J.M.S., R.J,O.), and Department of Ophthalmology, Washington University School of Medicine (J.M.S., R.J.O.).
Inquiries to R. Joseph Olk, M.D., Retina Consultants, Ltd., Ste. 17413, East Pavilion, One Barnes Hospital Plaza, St. Louis, MO 63110.
A sutureless self-retaining infusion cannula (Sur-Med Instrument Company, 9422 Gravois Rd., St. Louis, MO 63123) was designed as a
578
November, 1990
AMERICAN JOURNAL OF OPHTHALMOLOGY
Reference 1. Hilton, G. F.: Sutureless self-retaining infusion cannula for pars plana vitrectomy. Am. J. Ophthalmol. 99:612,1985.
Fig. 1 (Mason, Sullivan, and Olk). Modified sutureless self-retaining infusion cannula (x 5). modification of a prototype by Hilton.! The cannula has a beveled 19-9auge tubular element and a smaller 20-gauge shelf to support the device transsclerally (Fig. 1). The total intraocular length of the cannula is 4.0 mm. It is placed through a 19-9auge sclerotomy entry (Fig. 2). A preplaced sclerotomy suture is used to facilitate closure at the conclusion of the operation. The cannula is attached by flexible Silastic tubing to an 18-gauge needle adapter for connection to standard infusion equipment. The step design of the cannula proper and the broad-based flange provide excellent stability for a hydrodynamically closed system during pars plana vitrectomy. We have used the device successfully in more than 400 procedures including phakic, pseudophakic, and aphakic eyes without complications.
Fig. 2 (Mason, Sullivan, and Olk). Intraoperative photograph with modified sutureless self-retaining infusion cannula placed in inferotemporal quadrant of left eye.
Liability for Intraocular Lens Calculations Michael S. Insler, M.D.
Department of Ophthalmology, LSU Eye Center, Louisiana State University Medical Center School of Medicine. Inquiries to Michael S. lnsler, M.D., LSU Eye Center, 2020 Gravier St., Ste. B, New Orleans, LA 70112-2234.
A favorable outcome after cataract extraction with intraocular lens insertion depends on many variables. Even after uncomplicated surgery, the patient may not see well because of errors in the calculation of lens power. Standard formulas for normal, as well as short and long eyes, are used to predict a postoperative result as close to emmetropia as possible.' These formulas notwithstanding, technical errors still occur and may result in physician liability. A Louisiana plaintiff brought a medical malpractice action against a local physician who performed cataract surgery, alleging that the physician negligently installed the incorrect intraocular lens that caused impaired vision." The Court held that the physician's medical technician did not obtain the correct keratometry and axial length measurements, which would have resulted in an intraocular lens power of +33 diopters for adequate vision instead of the + 25-diopter power intraocular lens that was implanted at the time of surgery. The Court awarded general damage in the amount of $50,000. The question before the Court was whether this mistake or miscalculation was a breach of the standard of care. The evidence from expert and factual testimony disclosed that measurements could have been taken improperly through human error. The record disclosed three causes for the error in intraocular lens calculation: inaccurate axial length measurements, which resulted from human error; failure to take comparison measurements of the contralateral eye {this is a common practice among ophthalmologists and is also suggested
Letters to the Journal
577
4. Forstot, S. 1., and Damiano, R. E.: Trauma after radial keratotomy. Ophthalmology 95:833, 1988. 5. Binder, P. S., Waring, G. 0., Arrowsmith, P. N., and Wang, c.: Histopathology of traumatic corneal rupture after radial keratotomy. Arch. Ophthalmol. 106:1584, 1988.
Translimbal Iris Hook for Pupillary Dilation During Vitreous Surgery Dwain G. Fuller, M.D., and Donald L. Wilson, M.D. Texas Retina Associates (D.G.F.) and Midwest Eye Institute (D.L.W.).
Inquiries to Dwain G. Fuller, M.D., 7150 Greenville Ave., Dallas, TX 75231.
A number of techniques have been described for achieving wide pupillary dilation to facilitate peripheral vitreoretinal procedures. During protracted surgery with vitreous base dissection, pharmacologic approaches, such as preoperative flurbiprofen or epinephrine in the infusion system, often fail to prevent miosis. Iris sphincterotomy and iridectomy can be used, but they are cosmetically objectionable and may cause bleeding. Mechanical stretching of the iris can be achieved with sutures-! or with a recently described intraocular tack." We devised a translimbal iris hook that we believe offers advantages over the use of intraocular sutures or tacks for iris stretching. The hook can be simply fashioned from a small length of 0.3-mm diameter stainless steel wire. A piece of solid silicone (cut from a silicone rod used for scleral buckling) is threaded onto the noncurved end of the wire to serve as a stop. A microvitreoretinal blade is used to enter the anterior chamber. The iris hook is passed into the anterior chamber through the limbal incision, and the pupillary margin is engaged. Partial withdrawal of the wire permits the desired state of dilation to be achieved. The distal end of the wire is then carefully grasped with a needle holder, and the silicone stop is snugged down to the corneosclerallimbus (Figure). The placement of one hook may be adequate if wide dilation is required in only one quadrant. At the conclusion of the surgery the hooks are removed, and the limbal entrance sites are each closed with a single 8-0 Vicry I suture. This device is well suited to aphakic and pseudophakic eyes and may be applicable to phakic eyes in selected cases. We have used this hook to retract the iris to permit successful extraction of a small foreign body lodged be-
Figure (Fuller and Wilson). The use of two translimbal iris hooks.
tween the inferior iris and the anterior lens capsule.
References 1. Eckardt, c.: Pupillary stretching. A new procedure in vitreous surgery. Retina 5:235, 1985. 2. Zivojnovic, R.: Silicone Oil in Vitreous Surgery. The Netherlands, Martinus Nijhoff Publishers, 1987, p.126. 3. McCuen, B. W., II, Hickingbotharn, D., Tsai, M., and de Juan, E., Jr.: Temporary iris fixation with a micro-iris retractor. Arch. Ophthalmol. 107:925, 1989.
A Sutureless Self-Retaining Infusion Cannula for Pars Plana Vitrectomy Genevieve Mason, R.N., J. Michael Sullivan, M.D., and R. Joseph Olk, M.D. Barnes Hospital (G.M., J.M.S., R.J,O.), and Department of Ophthalmology, Washington University School of Medicine (J.M.S., R.J.O.).
Inquiries to R. Joseph Olk, M.D., Retina Consultants, Ltd., Ste. 17413, East Pavilion, One Barnes Hospital Plaza, St. Louis, MO 63110.
A sutureless self-retaining infusion cannula (Sur-Med Instrument Company, 9422 Gravois Rd., St. Louis, MO 63123) was designed as a
578
November, 1990
AMERICAN JOURNAL OF OPHTHALMOLOGY
Reference 1. Hilton, G. F.: Sutureless self-retaining infusion cannula for pars plana vitrectomy. Am. J. Ophthalmol. 99:612,1985.
Fig. 1 (Mason, Sullivan, and Olk). Modified sutureless self-retaining infusion cannula (x 5). modification of a prototype by Hilton.! The cannula has a beveled 19-9auge tubular element and a smaller 20-gauge shelf to support the device transsclerally (Fig. 1). The total intraocular length of the cannula is 4.0 mm. It is placed through a 19-9auge sclerotomy entry (Fig. 2). A preplaced sclerotomy suture is used to facilitate closure at the conclusion of the operation. The cannula is attached by flexible Silastic tubing to an 18-gauge needle adapter for connection to standard infusion equipment. The step design of the cannula proper and the broad-based flange provide excellent stability for a hydrodynamically closed system during pars plana vitrectomy. We have used the device successfully in more than 400 procedures including phakic, pseudophakic, and aphakic eyes without complications.
Fig. 2 (Mason, Sullivan, and Olk). Intraoperative photograph with modified sutureless self-retaining infusion cannula placed in inferotemporal quadrant of left eye.
Liability for Intraocular Lens Calculations Michael S. Insler, M.D.
Department of Ophthalmology, LSU Eye Center, Louisiana State University Medical Center School of Medicine. Inquiries to Michael S. lnsler, M.D., LSU Eye Center, 2020 Gravier St., Ste. B, New Orleans, LA 70112-2234.
A favorable outcome after cataract extraction with intraocular lens insertion depends on many variables. Even after uncomplicated surgery, the patient may not see well because of errors in the calculation of lens power. Standard formulas for normal, as well as short and long eyes, are used to predict a postoperative result as close to emmetropia as possible.' These formulas notwithstanding, technical errors still occur and may result in physician liability. A Louisiana plaintiff brought a medical malpractice action against a local physician who performed cataract surgery, alleging that the physician negligently installed the incorrect intraocular lens that caused impaired vision." The Court held that the physician's medical technician did not obtain the correct keratometry and axial length measurements, which would have resulted in an intraocular lens power of +33 diopters for adequate vision instead of the + 25-diopter power intraocular lens that was implanted at the time of surgery. The Court awarded general damage in the amount of $50,000. The question before the Court was whether this mistake or miscalculation was a breach of the standard of care. The evidence from expert and factual testimony disclosed that measurements could have been taken improperly through human error. The record disclosed three causes for the error in intraocular lens calculation: inaccurate axial length measurements, which resulted from human error; failure to take comparison measurements of the contralateral eye {this is a common practice among ophthalmologists and is also suggested
