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Anisophoria after implantation of an intraocular lens
to damage ocular tissue when compressed than more rigid anterior chamber lenses. Considering the force required to reopen the wound and expel the lens, remarkably little ocular injury occurred. We suspect that greater injury might have occurred with a more rigid lens. We have implanted this lens in many patients, and none have complained of tenderness-to-touch. While with most patients the absence of tenderness-to-touch is a distinct advantage, with this patient, ironically, it might have been a disadvantage. He had noted mild tenderness-to-touch in the eye with an Omnifit II lens. He might have been less aware of and therefore less careful with the second eye because of its lack of tenderness. It is also possible that the patient was less cautious because he was already seeing well with the previously operated eye. There is perhaps more risk in implanting the second eyes of patients who are potentially unreliable and noncompliant. REFERENCES 1. Corboy JM, Ing MR: Traumatic loss of an anterior chamber lens. Am Intra-Ocular Implant Soc j 5:54-55, 1979 2. Cobble CR: Traumatic expulsion of an intraocular lens. Am j Ophthalmol 94:263, 1982 3. Fenzl RE, Hahs G: Evaluation of semiflexible and flexible anterior chamber intraocular lenses. Am Intra-Ocular Implant Soc j 9:42-44, 1983
Goniomegaly associated with a normal cornea, increased axial length, and minimal refractive error Scott L. Dolin, M.D. Sanford D. Hecht, M.D. Waltham, Massachusetts
ABSTRACT The association of a large axial length with a small refractive error and a normal corneal diameter should alert the lens implant surgeon to the possibility that goniomegaly is present. We report a patient whose intraoperative anterior chamber diameter was measured as 15 mm. It was necessary to insert a modified posterior chamber intraocular lens instead of an anterior chamber lens. Key Words: axial length, corneal curvature, goniomegaly, intraocular lens, megalophthalmos
It is well known that implanting an anterior chamber lens of correct size is important. Horizontal white-towhite limbal measurements are generally proportional to anterior chamber diameter and are therefore used as a guide to lens sizing. We report a patient with normal corneal diameter, minimal refractive error, normal although flat corneal curvature, and increased axial length whose very large anterior chamber diameter made placement of an anterior chamber lens impossible.
CASE REPORT A 45-year-old man presented with a complaint of decreased vision in his left eye. Visual acuity was 20/20 in the right eye and 20170 in the left eye. His past correction was -0.50 +1.00 x 88° in the right eye and -2.50 +1.50 x 87° in the left eye. Refraction of the left eye yielded no improvement of vision with a best correction of -1.50 +1.25 x 88°. Slitlamp exam revealed posterior subcapsular cataracts in both eyes, worse in the left. Fundus exam was normal in both eyes. The patient was scheduled for cataract extraction with intraocular lens (IOL) implantation in the left eye. joseph Goldstein, R.Ph., C.O.A., assisted with the manuscript. Reprint requests to Scott L. Dolin, M.D., Boston Eye Research Institute, 20 Hope Avenue, Suite 106, Waltham, Massachusetts, 02154. 288
AM INTRA-OCULAR IMPLANT SOC J-VOL 11, MAY 1985
Keratometric readings were 39.00 horizontally and 40.00 at 105 degrees in the right eye and 39.00 horizontally and 40.25 at 90 degrees in the left eye. Ultrasonic axial length measurements were 26.3 mm in the right eye and 26.6 mm in the left eye. The right cornea was 12.00 mm in diameter and the left eye was 12.25 mm. The Binkhorst formula indicated a need for a +13.44 diopter (D) iris plane lens. The patient had an uneventful extracapsular cataract extraction without posterior capsulotomy. At the time of surgery, a + 12.00 Choyce Mark IX anterior chamber lens that measured 13.0 mm in length was placed in the eye. The lens was grossly too short. It was replaced with a 14.0 mm Mark IX implant. This lens was also grossly too short. Intraoperative use of the Hecht anteriorchamberangle gauge (S.D. Hecht, M.D., poster presentation, American Academy of Ophthalmology Meeting, Kansas City, Missouri, October 1978) had verified this finding. It indicated that a 15.0 mm lens would likely fit correctly. A +14.0 D Sinskey-style posterior chamber lens, measuring 13.5 mm in length, was placed in the ciliary sulcus after the lens loops had been uncurled to increase the length by at least 1 mm. The lens was placed without complication and seemed to be stable. Visual acuity on the third postoperative day was 20/25. The postoperative course was benign and the IOL remained in good and stable position. Two months postoperatively the vision was 20/20 with correction of -0.25 +1.50 x 10°. DISCUSSION Various techniques have been used to determine the normal length of the eye. Duke-Elderl(p82) summarized several anatomic studies by stating that the average measurement for axial length in normal eyes is an outside dimension of 24.15 mm and an inside dimension of 22.12 mm. Ultrasonographic measurements indicate an average distance of 23.37 mm from the anterior corneal surface to the vitreoretinal interface. 2,3 The accuracy of this method, widely used in clinical practice, has been confirmed. 2 The results with computed tomography are similar. 4 The radius of curvature of the cornea has been found to be directly proportional to the axial length in normal eyes .5 This case demonstrated the same association. Duke-Elder1(pI87) states that the diameter of the anterior chamber varies between 11.3 mm and 12.4 mm. Clinically, this dimension is estimated by measuring the horizontal corneal diameter and adding 1 mm; the corneal diameter has been found to average 11.34 mm and range from 10.75 mm to 12.00 mm. 3,6 The breadth of the anterior chamber reported here is notable. With a corneal diameter of12 .25 mm, well within the normal range, it was expected that a 13.00 mm lens would fit correctly. However, it was found that even a 14.00 mm
length implant was far too short. The inaccuracy of the corneal diameter in estimating the anterior chamber breadth was first reported by Heslin. 7 He found that the horizontal corneal diameter plus one millimeter measurement as recommended by Choyce accurately estimated anterior chamber diameter in only 40% of eyes. The relationship between refractive error and axial length also deserves mention. Although the preoperative refractive error was only -0.87 D spherical equivalent, the axial length of the eye was 26.6 mm, much longer than normal. Partial explanation is found in the relatively flat corneal curvature. One can also speculate that the lens size or density was less than normal or that the lens was more posteriorly placed than is usual. However, the anterior chamber did not seem to be overly deep nor did the lens seem retroplaced. Furthermore, no iridodonesis was present. The management of IOL implantation in clinical anterior megalophthalmos has recently been described. 8 The large corneas and anterior segments required the use of an iris supported IOL in two patients. In our case the corneal diameter was normal and the anterior segment was clinically unremarkable. The association of a long axial length with a small refractive error and a normal corneal diameter should alert the lens implant surgeon to the possibility that goniomegaly is present. REFERENCES 1. Duke-Elder S: System of Ophthalmology. II: Anatomy of the Visual System. London, H enry Kimpton Co, 1961 2. Binkhorst RD: The accuracy of ultrasonic measurement of the axial length of the eye. Ophthalmic Surg 12:363-365, 1981 3 . Francois J, Goes F: Ultrasonographic study of 100 emmetropic eyes. Ophthalmologica 175:321-327, 1977 4. Crow W, Guinto FC Jr, Amparo E, Stewart K: Normal in vivo eye dimensions by computed tomography. J Comput Assist Tomogr 6:708-710, 1982 5. Lowe RF: Corneal radius and ocular correlations; in normal eyes with primary angle-closure glaucoma. Am J Ophthalmol 67:864-868, 1969 6. Choyce DP: Intra-ocular Lenses and Implants. London, HK Lewis & Co, 1964, p 36 7. Heslin KB: Is "white-to-white" right? Am Intra-Ocular Implant Soc J 5:50-51, 1979 8. Neumann AC: Anterior megalophthalmos and intraocular lens implantation. Am Intra-Ocular Implant Soc J 10:220-222, 1984
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Goniomegaly associated with a normal cornea, increased axial length, and minimal refractive error Scott L. Dolin, M.D. Sanford D. Hecht, M.D. Waltham, Massachusetts
ABSTRACT The association of a large axial length with a small refractive error and a normal corneal diameter should alert the lens implant surgeon to the possibility that goniomegaly is present. We report a patient whose intraoperative anterior chamber diameter was measured as 15 mm. It was necessary to insert a modified posterior chamber intraocular lens instead of an anterior chamber lens. Key Words: axial length, corneal curvature, goniomegaly, intraocular lens, megalophthalmos
It is well known that implanting an anterior chamber lens of correct size is important. Horizontal white-towhite limbal measurements are generally proportional to anterior chamber diameter and are therefore used as a guide to lens sizing. We report a patient with normal corneal diameter, minimal refractive error, normal although flat corneal curvature, and increased axial length whose very large anterior chamber diameter made placement of an anterior chamber lens impossible.
CASE REPORT A 45-year-old man presented with a complaint of decreased vision in his left eye. Visual acuity was 20/20 in the right eye and 20170 in the left eye. His past correction was -0.50 +1.00 x 88° in the right eye and -2.50 +1.50 x 87° in the left eye. Refraction of the left eye yielded no improvement of vision with a best correction of -1.50 +1.25 x 88°. Slitlamp exam revealed posterior subcapsular cataracts in both eyes, worse in the left. Fundus exam was normal in both eyes. The patient was scheduled for cataract extraction with intraocular lens (IOL) implantation in the left eye. joseph Goldstein, R.Ph., C.O.A., assisted with the manuscript. Reprint requests to Scott L. Dolin, M.D., Boston Eye Research Institute, 20 Hope Avenue, Suite 106, Waltham, Massachusetts, 02154. 288
AM INTRA-OCULAR IMPLANT SOC J-VOL 11, MAY 1985
Keratometric readings were 39.00 horizontally and 40.00 at 105 degrees in the right eye and 39.00 horizontally and 40.25 at 90 degrees in the left eye. Ultrasonic axial length measurements were 26.3 mm in the right eye and 26.6 mm in the left eye. The right cornea was 12.00 mm in diameter and the left eye was 12.25 mm. The Binkhorst formula indicated a need for a +13.44 diopter (D) iris plane lens. The patient had an uneventful extracapsular cataract extraction without posterior capsulotomy. At the time of surgery, a + 12.00 Choyce Mark IX anterior chamber lens that measured 13.0 mm in length was placed in the eye. The lens was grossly too short. It was replaced with a 14.0 mm Mark IX implant. This lens was also grossly too short. Intraoperative use of the Hecht anteriorchamberangle gauge (S.D. Hecht, M.D., poster presentation, American Academy of Ophthalmology Meeting, Kansas City, Missouri, October 1978) had verified this finding. It indicated that a 15.0 mm lens would likely fit correctly. A +14.0 D Sinskey-style posterior chamber lens, measuring 13.5 mm in length, was placed in the ciliary sulcus after the lens loops had been uncurled to increase the length by at least 1 mm. The lens was placed without complication and seemed to be stable. Visual acuity on the third postoperative day was 20/25. The postoperative course was benign and the IOL remained in good and stable position. Two months postoperatively the vision was 20/20 with correction of -0.25 +1.50 x 10°. DISCUSSION Various techniques have been used to determine the normal length of the eye. Duke-Elderl(p82) summarized several anatomic studies by stating that the average measurement for axial length in normal eyes is an outside dimension of 24.15 mm and an inside dimension of 22.12 mm. Ultrasonographic measurements indicate an average distance of 23.37 mm from the anterior corneal surface to the vitreoretinal interface. 2,3 The accuracy of this method, widely used in clinical practice, has been confirmed. 2 The results with computed tomography are similar. 4 The radius of curvature of the cornea has been found to be directly proportional to the axial length in normal eyes .5 This case demonstrated the same association. Duke-Elder1(pI87) states that the diameter of the anterior chamber varies between 11.3 mm and 12.4 mm. Clinically, this dimension is estimated by measuring the horizontal corneal diameter and adding 1 mm; the corneal diameter has been found to average 11.34 mm and range from 10.75 mm to 12.00 mm. 3,6 The breadth of the anterior chamber reported here is notable. With a corneal diameter of12 .25 mm, well within the normal range, it was expected that a 13.00 mm lens would fit correctly. However, it was found that even a 14.00 mm
length implant was far too short. The inaccuracy of the corneal diameter in estimating the anterior chamber breadth was first reported by Heslin. 7 He found that the horizontal corneal diameter plus one millimeter measurement as recommended by Choyce accurately estimated anterior chamber diameter in only 40% of eyes. The relationship between refractive error and axial length also deserves mention. Although the preoperative refractive error was only -0.87 D spherical equivalent, the axial length of the eye was 26.6 mm, much longer than normal. Partial explanation is found in the relatively flat corneal curvature. One can also speculate that the lens size or density was less than normal or that the lens was more posteriorly placed than is usual. However, the anterior chamber did not seem to be overly deep nor did the lens seem retroplaced. Furthermore, no iridodonesis was present. The management of IOL implantation in clinical anterior megalophthalmos has recently been described. 8 The large corneas and anterior segments required the use of an iris supported IOL in two patients. In our case the corneal diameter was normal and the anterior segment was clinically unremarkable. The association of a long axial length with a small refractive error and a normal corneal diameter should alert the lens implant surgeon to the possibility that goniomegaly is present. REFERENCES 1. Duke-Elder S: System of Ophthalmology. II: Anatomy of the Visual System. London, H enry Kimpton Co, 1961 2. Binkhorst RD: The accuracy of ultrasonic measurement of the axial length of the eye. Ophthalmic Surg 12:363-365, 1981 3 . Francois J, Goes F: Ultrasonographic study of 100 emmetropic eyes. Ophthalmologica 175:321-327, 1977 4. Crow W, Guinto FC Jr, Amparo E, Stewart K: Normal in vivo eye dimensions by computed tomography. J Comput Assist Tomogr 6:708-710, 1982 5. Lowe RF: Corneal radius and ocular correlations; in normal eyes with primary angle-closure glaucoma. Am J Ophthalmol 67:864-868, 1969 6. Choyce DP: Intra-ocular Lenses and Implants. London, HK Lewis & Co, 1964, p 36 7. Heslin KB: Is "white-to-white" right? Am Intra-Ocular Implant Soc J 5:50-51, 1979 8. Neumann AC: Anterior megalophthalmos and intraocular lens implantation. Am Intra-Ocular Implant Soc J 10:220-222, 1984
AM INTRA-OCULAR IMPLANT SOC J-VOL 11, MAY 1985
289