- Email: [email protected]
Haptic Breakage in One-Piece Poly(Methyl Methacrylate) Intraocular Lenses
REFERENCES 1. McEwen BS, DeKloet ER, Rostene W. Adrenal steroid receptors and actions in the nervous system. Physiol Rev 1986; 66:1121-1188 2. Merriam J, Lipsett M. Catechol Estrogens. New York, Raven Press, 1983 3. Siegel G, Agranoff B, Albers RW, Molinoff P, eds. Basic Neurochemistrv, 4th ed. 1989; 350-354 4. Harris MA, S'chwartz B. Steroid potentiation of betaadrenergic-sensitive adenylate cyclase in rabbit ciliary processes. Invest Ophthalmol Vis Sci 1987; 28:1024-1027
HAPTIC BREAKAGE IN ONE-PIECE POLY(METHYL METHACRYLATE) INTRAOCULAR LENSES To the Editor: There are several possible disadvantages to the use of polypropylene and nylon in the construction of intraocular lens haptics. 1 -4 Consequently, flexible-loop posterior chamber lenses, which have been lathe-cut or molded from a single piece of poly(methyl methacrylate) (PMMA), have increased in popularity. The surgical technique used to implant these all- PMMA one-piece lenses is frequently little modified from that used for lenses with polypropylene haptics. We describe an unusual complication of such a procedure and suggest how the problem may be avoided.
CASE REPORT A 75-year-old man had extracapsular cataract extraction and insertion of an Iolab 6842B formflex one-piece intraocular lens. The operation was per-
Fig. 1.
formed by an experienced surgeon under local anesthesia. The superior haptic of the lens was placed in the ciliary sulcus by flexion of the haptic into the pupil with posterior displacement and release. On completion of this maneuver it was noted that the haptic had broken close to its junction with the optic (Figure 1). Lens exchange was performed through a sector iridectomy. However, a thorough search failed to identify the location of the haptic fragment within the eye. The operation and postoperative course was otherwise uneventful and visual acuity had improved to 20/40 three months postoperatively (Figure 2). The missing haptic has still not been identified despite repeated postoperative examinations with intense pupil dilation and ultrasonography. It is assumed to be within the peripheral confines of the posterior chamber of the eye. Various manufacturing techniques have been used by different companies to reduce the inherent brittleness of PMMA. However, this case suggests that a fracture can still develop in a susceptible lens with the kind of stresses induced by conventional surgical manipulation. We are aware of similar events involving two Allergan PC57B one-piece lenses and two Rayner 752U one-piece lenses. In each case the break occurred close to the optic! haptic junction. Fortunately, breakage was recognized prior to insertion into the eye. It is notable that all three lens designs were lathe-cut from unmodified Perspex CQ (ICI). Although the tensile strength of Perspex is high, 91.6 MPa, it is highly "notch sensitive" {product information catalogue 1991). Unlike those constructed of nylon or poly-
(Ainsworth) Scanning electron microscopy of fracture site. Left: Numerous cracks have appeared at the site of maximum deformation during lens insertion. Right: When the undamaged haptic is examined, it can be seen that the break has occurred at a narrowing adjacent to the junction of haptic and optic.
J CATARACT REFRACT SURG-VOL
17, NOVEMBER 1991
863
CILIARY SULCUS FIXATION - STILL A SHOT IN THE DARK
Fig. 2.
(Ainsworth) Patient's eye postoperatively. A lens exchange has been performed through a sector iridectomy, which was subsequently closed with a single 10-0 polypropylene suture.
propylene, the breaking strain of a PMMA haptic will be reduced considerably in the presence of a surface imperfection induced during design, manufacture, packaging, or surgical use. Failure is sudden and without warning due to rapid crack propagation (Figure 1, left). It would seem advisable to pay particular attention to the opticlhaptic junction when inspecting one-piece lenses prior to use. The technique of superior haptic insertion into the posterior chamber by lens dialing alone has been adopted by the authors since this incident when using lenses constructed of unmodified PMMA, as we assume that such a change in technique would reduce the distortion necessary for correct placement of the lens. John Ross Ainsworth, F.R.C.S., FC.Ophth A. Fiona Spencer, F.R.C.S., FC.Ophth Glasgow, Scotland REFERENCES
1. Apple DJ, Mamalis N, Lotfield K, et al: Complications of intraocular lenses. A historical and histopathological review. Surv Ophthalmol1984; 29:1-28 2. Masket S. Pseudophakic posterior iris chafing syndrome. J Cataract Refract Surg 1986; 12:252-256 3. Apple DJ, Mamalis N, Brady SE, et al. Biocompatibilityof implant materials: a review and scanning electron microscopic study. Am Intra-Ocular Implant Soc J 1984; 10:53-66. 4. Tuberville AW, Galin MA, Perez HD, et al. Complement activation by nylon and polypropylene-looped prosthetic intraocular lenses. Invest Ophthalmol Vis Sci 1982; 22:727-733 864
J CATARACT REFRACT
To the Editor: The fixation of the haptics of the intraocular lens (IOL) to the ciliary sulcus has become an accepted procedure in selected cases. 1- 4 The known complications of this procedure include intraoperative bleeding from inadvertent puncture of the ciliary body, IOL tilting,4 ciliary body erosion and focal obliteration of the major arterial circle of the iris, 5 as well as breakdown of the blood-aqueous barrier. 6 We would like to present an unusual association of surgical complications, namely the breaking of a haptic and the consequent embedding of the suture into the ciliary body. CASE REPORT A 13-year-old boy presented at the Eye Department of the Boksburg-Benoni Hospital with a limbus-to-limbus corneal perforation, passing in a curved manner from 10 o'clock to 3 o'clock. The eye also had a hyphema, a traumatic cataract, and a vitreous hemorrhage that obscured visualization of the fundus. The injury was four days old and his visual acuity was light perception. The corneal wound was closed with 10-0 nylon sutures. Wash-out of the hyphema and the traumatic cataract were performed through an upper limbal incision. An anterior vitrectomy was also done at this time. Since the posterior capsule was not intact, a 20.5 diopter one-piece IOL (3M style 190) was implanted by suturing it into the ciliary sulcus. The 10-0 polypropylene (Prolene®) suture at the 5 o'clock position was placed uneventfully. When the second haptic was sutured at the 11 o'clock position, resistance was felt, followed by easing and intraoperative bleeding. We suspected that the haptic had broken, but we were unable to remove the IOL at this time. The next day the patient left the hospital unauthorized. He returned to the department 28 days later, with a blind, painful eye. The eye was enucleated and a large corneoscleral button was removed. The specimen was first photographed from its inner aspect and then histologically analyzed. The photograph shows the 5 o'clock haptic overlying the pars plicata (out of focus). The haptic at 11 o'clock is separated from the optic, broken near its insertion, and a piece of Prolene suture is evident over the ciliary body at 3 o'clock (Figure 1). The histologic examination, after removal, confirmed the presence of the suture embedded in the ciliary body. This case emphasizes that this procedure deals with a hidden surgical zone. The combination of sulcus reconstruction 7 and the use of a specially
SURG-VOL 17, NOVEMBER 1991
HAPTIC BREAKAGE IN ONE-PIECE POLY(METHYL METHACRYLATE) INTRAOCULAR LENSES To the Editor: There are several possible disadvantages to the use of polypropylene and nylon in the construction of intraocular lens haptics. 1 -4 Consequently, flexible-loop posterior chamber lenses, which have been lathe-cut or molded from a single piece of poly(methyl methacrylate) (PMMA), have increased in popularity. The surgical technique used to implant these all- PMMA one-piece lenses is frequently little modified from that used for lenses with polypropylene haptics. We describe an unusual complication of such a procedure and suggest how the problem may be avoided.
CASE REPORT A 75-year-old man had extracapsular cataract extraction and insertion of an Iolab 6842B formflex one-piece intraocular lens. The operation was per-
Fig. 1.
formed by an experienced surgeon under local anesthesia. The superior haptic of the lens was placed in the ciliary sulcus by flexion of the haptic into the pupil with posterior displacement and release. On completion of this maneuver it was noted that the haptic had broken close to its junction with the optic (Figure 1). Lens exchange was performed through a sector iridectomy. However, a thorough search failed to identify the location of the haptic fragment within the eye. The operation and postoperative course was otherwise uneventful and visual acuity had improved to 20/40 three months postoperatively (Figure 2). The missing haptic has still not been identified despite repeated postoperative examinations with intense pupil dilation and ultrasonography. It is assumed to be within the peripheral confines of the posterior chamber of the eye. Various manufacturing techniques have been used by different companies to reduce the inherent brittleness of PMMA. However, this case suggests that a fracture can still develop in a susceptible lens with the kind of stresses induced by conventional surgical manipulation. We are aware of similar events involving two Allergan PC57B one-piece lenses and two Rayner 752U one-piece lenses. In each case the break occurred close to the optic! haptic junction. Fortunately, breakage was recognized prior to insertion into the eye. It is notable that all three lens designs were lathe-cut from unmodified Perspex CQ (ICI). Although the tensile strength of Perspex is high, 91.6 MPa, it is highly "notch sensitive" {product information catalogue 1991). Unlike those constructed of nylon or poly-
(Ainsworth) Scanning electron microscopy of fracture site. Left: Numerous cracks have appeared at the site of maximum deformation during lens insertion. Right: When the undamaged haptic is examined, it can be seen that the break has occurred at a narrowing adjacent to the junction of haptic and optic.
J CATARACT REFRACT SURG-VOL
17, NOVEMBER 1991
863
CILIARY SULCUS FIXATION - STILL A SHOT IN THE DARK
Fig. 2.
(Ainsworth) Patient's eye postoperatively. A lens exchange has been performed through a sector iridectomy, which was subsequently closed with a single 10-0 polypropylene suture.
propylene, the breaking strain of a PMMA haptic will be reduced considerably in the presence of a surface imperfection induced during design, manufacture, packaging, or surgical use. Failure is sudden and without warning due to rapid crack propagation (Figure 1, left). It would seem advisable to pay particular attention to the opticlhaptic junction when inspecting one-piece lenses prior to use. The technique of superior haptic insertion into the posterior chamber by lens dialing alone has been adopted by the authors since this incident when using lenses constructed of unmodified PMMA, as we assume that such a change in technique would reduce the distortion necessary for correct placement of the lens. John Ross Ainsworth, F.R.C.S., FC.Ophth A. Fiona Spencer, F.R.C.S., FC.Ophth Glasgow, Scotland REFERENCES
1. Apple DJ, Mamalis N, Lotfield K, et al: Complications of intraocular lenses. A historical and histopathological review. Surv Ophthalmol1984; 29:1-28 2. Masket S. Pseudophakic posterior iris chafing syndrome. J Cataract Refract Surg 1986; 12:252-256 3. Apple DJ, Mamalis N, Brady SE, et al. Biocompatibilityof implant materials: a review and scanning electron microscopic study. Am Intra-Ocular Implant Soc J 1984; 10:53-66. 4. Tuberville AW, Galin MA, Perez HD, et al. Complement activation by nylon and polypropylene-looped prosthetic intraocular lenses. Invest Ophthalmol Vis Sci 1982; 22:727-733 864
J CATARACT REFRACT
To the Editor: The fixation of the haptics of the intraocular lens (IOL) to the ciliary sulcus has become an accepted procedure in selected cases. 1- 4 The known complications of this procedure include intraoperative bleeding from inadvertent puncture of the ciliary body, IOL tilting,4 ciliary body erosion and focal obliteration of the major arterial circle of the iris, 5 as well as breakdown of the blood-aqueous barrier. 6 We would like to present an unusual association of surgical complications, namely the breaking of a haptic and the consequent embedding of the suture into the ciliary body. CASE REPORT A 13-year-old boy presented at the Eye Department of the Boksburg-Benoni Hospital with a limbus-to-limbus corneal perforation, passing in a curved manner from 10 o'clock to 3 o'clock. The eye also had a hyphema, a traumatic cataract, and a vitreous hemorrhage that obscured visualization of the fundus. The injury was four days old and his visual acuity was light perception. The corneal wound was closed with 10-0 nylon sutures. Wash-out of the hyphema and the traumatic cataract were performed through an upper limbal incision. An anterior vitrectomy was also done at this time. Since the posterior capsule was not intact, a 20.5 diopter one-piece IOL (3M style 190) was implanted by suturing it into the ciliary sulcus. The 10-0 polypropylene (Prolene®) suture at the 5 o'clock position was placed uneventfully. When the second haptic was sutured at the 11 o'clock position, resistance was felt, followed by easing and intraoperative bleeding. We suspected that the haptic had broken, but we were unable to remove the IOL at this time. The next day the patient left the hospital unauthorized. He returned to the department 28 days later, with a blind, painful eye. The eye was enucleated and a large corneoscleral button was removed. The specimen was first photographed from its inner aspect and then histologically analyzed. The photograph shows the 5 o'clock haptic overlying the pars plicata (out of focus). The haptic at 11 o'clock is separated from the optic, broken near its insertion, and a piece of Prolene suture is evident over the ciliary body at 3 o'clock (Figure 1). The histologic examination, after removal, confirmed the presence of the suture embedded in the ciliary body. This case emphasizes that this procedure deals with a hidden surgical zone. The combination of sulcus reconstruction 7 and the use of a specially
SURG-VOL 17, NOVEMBER 1991