Topographical anatomy of the ciliary sulcus

Topographical anatomy of the ciliary sulcus S. Gregory Smith, M.D. Wilmington, Delaware Frank Snowden, Ph.D. Elden G. Lamprecht, D.V.M., Ph.D. St. Paul, Minnesota

ABSTRACT The topography of the ciliary sulcus area in humans was examined by slitlamp biomicroscopy and scanning e1ectron microscopy. Characteristics of this area included the following: the sulcus was angulated anteriorly; the ciliary processes were of unequal length; the zonules did not insert on the tips of the ciliary processes but, instead, inserted slightly posteriorly; the contour of the sulcus area was irregular; bands stretched from the base of the ciHary processes to the posterior surface of the iris, making the sulcus a potential space in some areas of the eye. Effects of this topography on IOL imp1antation are postu1ated. Key Words: biomicroscopy, ciliary sulcus, intraocular lens, scanning electron microscopy, topography

Intraocular lenses (IOLs) have been designed with various loop configurations in order to achieve stability and centration with minimal injury to ocular tissues. Complications such as iris transillumination defects with and without microhyphemas, 1,2 pigmentary glaucoma, .3-6 neovascular glaucoma,7 vitreous hemorrhage,8 and increased blood aqueous barrier breakdown 9 have been noted with sulcus-fixated IOLs. Brems and coauthorslO have noted a 50% decentration rate of IOLs in autopsy eyes with symmetric loop placement in the sulcus. Surgeons, with increasing support from histopathologic studies, 11 have advocated placing the IOL in the bag to avoid these problems. However, many surgeons still place the IOL in the ciliary sulcus as a primary choice or as a secondary choice (i.e., ruptured posterior capsule). This paper

describes the important topographical features of the ciliary sulcus that affect IOL placement. In this study, the ciliary sulcus is defined as the transverse or circumferential valley between the posterior surface of the iris and the anterior surface of the ciliary processes. MATERIALS AND METHODS Thirty-two human cadaver eyes preserved in formalin were obtained and sectioned sagitally. Twenty were examined in detail under the operating microscope and the slitlamp to obtain an overview of their features, note the consistency of the findings, and determine the best way to demonstrate them photographically. Slitlamp photography (with two different cameras) and a 35-mm camera equipped with a macro

From the General Ophthalmology Service, Wills Eye Hospital, Philadelphia, Pennsylvania; Department of Ophthalmology, Hershey Medical Center, Hershey, Pennsylvania; 3M Vision CarelIOL Department, Health Care Enterprises Division, and Biosciences Laboratory, 3M, St. Paul, Minnesota. Supported in part by a grant from 3M Vision Care. Presented in part at the American-International IOL Congress, Boston, April 1985, and the European Intraocular Implant Congress, Cannes, October 1985. Reprint requests to S. Gregory Smith, M.D., 1700 Shallcross Avenue, Suite 2, Wilmington, Delaware 19806.

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lens were unsuccessful in producing detailed photographs because of light absorption by the pigment epithelium. A representative eye (70-year-old female) was then prepared for scanning electron microscopy (SEM). The cornea was removed and the eye was quartered. The quartered specimen, containing the lens with intact zonules, was dehydrated in graded alcohols through absolute ethanol. It was critical-point dried with CO 2 in a Polaron CPD device and sputtercoated with gold. Scanning electron microscopy was performed with an lSI SX-30 . Twelve eyes (six pairs) were then studied under the operating microscope to map the characteristics of the Ciliary processes. The eyes were sectioned sagitally, bisecting the superior and inferior rectus muscle insertions. The incision through the superior rectus muscle was designated as the 12-0'clock position and the processes were counted in a clockwise direction. Findings of individual ciliary processes were noted. Histologic studies were not performed.

RESULTS Proper orientation of the specimen was essential to achieve exposure of the normally opposed iris and ciliary body. Before tissue dehydration, the lens with zonules intact was reflected posteriorly and the iris reflected anteriorly over the limbus to expose the area known as the sulcus (Figure 1). The orientation of the iris in an intact globe would be approximately perpendicular to the photomicrograph, with the posterior surface of the iris in near contact with the tips of the ciliary processes. The ciliary processes were oriented radially on the inner surface of the ciliary body. The processes projected toward the center of the lens as much as 1 mm. The anterior portion of the ciliary process usually

Fig . 1.

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(Smith) Overview of the ciliary sulcus area. The le ns has bee n reflected poste riorl y and the iris, anteriorly.

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Fig. 2.

(Smith) Enlarged view of ciliary sulcus in Figure 1. The ciliary process labeled 1projects anteriorly toward th e iris more than th e ciliary process labeled 2 .

consisted of a projection into the posterior chamber toward the iris . These features have been noted by Streeten.l 2 This projection toward the iris created an anterior angulation to the valley of the sulcus. The ciliary processes were of uneven lengths. In Figure 2, the ciliary process on the left (1) is much closer to the reflected iris than the ciliary process on the right (2). These uneven lengths were also seen in all formalin-preserved eyes . Ciliary processes that extended to the poste rior iris surface occurred in seven of 12 eyes. The zonules did not insert on the tips of the ciliary processes but , instead, slightly posteriorly. This has also been noted by Streeten. 13 The sulcus had a highly irregular contour when viewed from the vantage point of Figure 1. In some eyes, this valley varied in depth as much as 1 mm from the base of the rece sses to the top of the ante rior posterior ridges. Bands of tissue stretching from the ciliary processes to the poste rior surface of the iris we re seen. These bands varied in thickness in both the formalin eyes and the represe ntative eye prepared for SEM (Figure 3). The band of tissue in Figure 4 is much thicker than that in Figure 3. The bands also varied in the height of their attachment along the face of the ciliary processes and the height of insertion on the posterior surface of the iris (Figure 3). The bands also coursed obliquely rathe r than radially (Figure 5). There was undoubtedly stretching artifact present in these photomicrographs. However, in the formalinfixed eyes with the iris in a more natural position, the bands appeared to have similar characteristics. Figure 6 is a goniophotograph that demonstrates the location of a band in vivo. Viewed through a peripheral

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Fig. 3.

(Smith) Further magnified view of sulcus area and sulcus band. The band on the left inserts much higher on the iris than the band on the right.

Fig. 5.

(Smith) Magnified view of an oblique sulcus band.

Fig. 4.

(Smith) Magnified view of a thick sulcus band.

Fig. 6.

(Smith) Goniophotograph of human eye with view of a sulcus band seen through the peripheral iridectomy (arrow).

iridectomy, the band can be seen in a location similar to the one demonstrated in the SEM prepared eye. These bands occurred as frequently as every other process or as infrequently as two to three per eye (Table 1). Figure 7 shows the band locations in the six pairs of eyes that were preserved in formalin immediately after enucleation. No clear-cut pattern existed in this sample to predict location of these bands.

appearance of this area, which may affect a lens loop as it is implanted. Streeten 12 ,13 has studied the ciliary Table 1. Frequency of bands in 12 eyes.

DISCUSSION The area of the ciliary body in which IOL loops may rest, known as the ciliary sulcus, has been studied in detail histologically and histopathologically.ll-19 However, there is little information on the topographical J CATARACT REFRACT SURG- VOL

Number of Bands OS

Sex

OD

52

F

71

M

5 13

M

10

M

6 27 36

Age

77 77 68 84

F M

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2 16 14 7 9

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Hours of a clock used to describe the positions of the ciliary processes ~

- Cyst of ciliary body __ Long ciliary process with full band

Long ciliary process _

Fig. 7.

(Smith) Diagrammatic representation oflocation of ciliary bands and long ciliary processes in human eyes. The eyes were oriented so the mid position of the superior rectus insertion was the plane of sectioning, and this was labeled 120' clock. The ciliary processes were counted individually and the presence of bands and long processes were noted. This linear diagram was then transcribed to clock hours to aid in planning IOL implantation.

body by SEM but not from the viewpoint of IOL placement. Kessel and Kardon 20 have performed SEM of this area in the orientation of the histological cross section but again not from the viewpoint of IOL placement. Our study of topographical features has shown th e ciliary sulcus to vary morphologically within a given eye. The features also vary from eye to eye (Figure 7). Unlike the more uniform anterior chamber angle, the contour can be quite irregular (Figure 1). The ciliary processes can extend forward almost as far as the posterior iris. The sulcus has an anterior angulation to the frontal plane of the lens in the intact eye. The zonules do not insert on the tips ofthe ciliary processes but rather more posteriorly, as Streeten has noted . 13 There are also bands across the sulcus at varying intervals and frequencies that extend from ciliary processes to the posterior surface of the iris. In certain 546

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areas, the sulcus may be limited in depth because of these bands. These findings would give a different cross-section view than has typically been seen with bands present periodically (Figure 8). These findings have some implications for IOL placement in this area. Because of the anterior angulation of the sulcus, it would be difficult to place the loops of an IOL in the sulcus without intact zonules; for example, placing a sulcus-fixated lens in an eye which had had intracapsular cataract extraction. Also, placing an IOL anterior to the capsular bag may not guarantee that the IOL will be located in the sulcus since the zonules do not insert on the tips of the ciliary processes and the processes themselves have been shown to be of unequal lengths. This has been confirmed in histopathologic studies by Champion, McDonnell, and Green 19 as well as by Apple and coauthors.21 The bands across the sulcus could direct the loop

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REFERENCES

Fig. 8.

(Smith) Top half of diagram is taken from artists' drawings of the ciliary sulcus area. It is misleading in the almost parallel opening of the sulcus to the lens plane, the insertion of the zonules on the tips of the ciliary processes, and the depiction of a clearly formed sulcus. The bottom half shows a more accurate representation. However, the band shown occurs only periodically and mayor may not be present in individual cross sections.

anteriorly into the iris if they were thick (Figure 4) or numerous (Figure 7: 84-year-old black male OD, 68year-old white female OD). This would be a possible explanation for the iris transillumination defect with microhyphema syndrome described by Johnson and coauthors. 1 This syndrome was noted to occur in 5% to 15% of eyes with a posterior chamber IOL in the sulcus, roughly correlating to two of the 12 eyes studied closely in our report. The varying location and number of these bands also make it difficult to know where to place an IOL to avoid them. Further work including histopathology is necessary to substantiate this correlation. Implications of this anatomy for dialing during IOL implantation, tissue erosion, and IOL length were not addressed in this static study. These implications as well as those discussed have been addressed in video format by Smith and Snowden (Anatomy of the Ciliary Sulcus and Its Implications for IOL Insertion. Video] Ophthalmol, Vol. 2, No.5, October 1986). J CATARACT

1. Johnson SH, Kratz RP, Olson PF: Iris transillumination defect and microhyphema syndrome. Am Intra-Ocular Implant Soc J 10:425-428, 1984 2. Masket S: Pseudophakic posterior iris chafing syndrome. J Cataract Refract Surg 12:252-256, 1986 3. Huber C: The gray iris syndrome; an iatrogenic form of pigmentary glaucoma. Arch Ophthalmol 102:397-398, 1984 4. Samples JR, Van Buskirk EM: Pigmentary glaucoma associated with posterior chamber intaocular lenses. Am J Ophthalmol 100:385-388, 1985 5. Smith JP: Pigmentary open-angle glaucoma secondary to posterior chamber intraocular lens implantation and erosion of the iris pigment epithelium. Am Intra-Ocular Implant Soc J 11:174-176, 1985 6. Woodhams JT, Lester JC: Pigmentary dispersion glaucoma secondary to posterior chamber intra-ocular lenses. Ann Ophthalmol 16:852-855, 1984 7. Apple DJ, Craythorn JM, Olson RJ, Little LE, et al: Anterior segment complications and neovascular glaucoma following implantation of a posterior chamber intraocular lens. Ophthalmology 91:403-419, 1984 8. Pazandak B, Johnson S, Kratz R, Faulkner GD: Recurrent intraocular hemorrhage associated with posterior chamber lens implantation. Am Intra-Ocular Implant Soc J 9:327-329, 1983 9. Miyake K, Asakura M, Kobayashi H: Effect of intraocular lens fixation on the blood-aqueous barrier. Am J Ophthalmol 98:451-455, 1984 10. Brems RN, Apple DJ, Pfeffer BR, Park SB, et al: Posterior chamber intraocular lenses in a series of75 autopsy eyes. Part III: Correlation of positioning holes and optic edges with the pupillary aperture and visual axis. J Cataract Refract Surg 12:367-371, 1986 11. Apple DJ, Reidy JJ, Googe JM, Mamalis N, et al: A comparison of ciliary sulcus and capsular bag fixation of posterior chamber intraocular lenses. Am Intra-Ocular Implant Soc J 11:44-63, 1985 12. Streeten BW: Ciliary body. In: Duane TD, Jaeger EA, eds, Biomedical Foundations of Ophthalmology. Philadelphia, Harper and Row, 1985, vol 1, chap 13 13. Streeten BW: Zonular apparatus. In: Duane TD, Jaeger EA, eds, Biomedical Foundations of Ophthalmology. Philadelphia, Harper and Row, 1985, vol 1, chap 14 14. Apple DJ, Mamalis N, Loftfield K, Googe JM, et al: Complications of intraocular lenses. A historical and histopathological review. SUI"V Ophthalmol 29:1-54, 1984 15. Champion R, Green WR: Intraocular lenses: A histopathologic study of eyes, ocular tissues, and intraocular lenses obtained surgically. Ophthalmology 92:1628-1645, 1985 16. McDonnell pJ, Green WR, Maumenee AE, IliffWJ: Pathology of intraocular lenses in 33 eyes examined postmortem. Ophthalmology 90:386-403, 1983 17. Mauriello JA J r, McLean IW, Wright JD J r: Loss of eyes after intraocular lens implantation; a clinico-pathologic study. Ophthalmology 90:378-385, 1983 18. McDonnell pJ, Patel A, Green WR: Comparison of intracapsular and extracapsular cataract surgery; histopathologic study of eyes obtained postmortem. Ophthalmology 92:1208-1225, 1985 19. Champion R, McDonnell pJ, Green WR: Intraocular lenses. Histopathologic characteristics of a large series of autopsy eyes. Surv Ophthalmol 30:1-32, 1985 20. Kessel RG, Kardon RH: Scanning Electron Microscopy. Philadelphia, WH Freeman & Company, 1979, p 104 21. Apple DJ, Park SB, Merkley KH, Brems RN, et al: Posterior chamber intraocular lenses in a series of75 autopsy eyes. Part I: Loop location. J Cataract Refract Surg 12:358-362, 1986

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