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Height of the Tarsus of the Lower Eyelid
HEIGHT OF THE TARSUS OF THE LOWER EYELID RALPH E. WESLEY, M.D., CLINTON D. MCCORD, JR., M.D., AND NORBERT A. JONES, PH.D. Atlanta, Georgia
The tarsal plate forms the supporting structure, or skeleton, of the eyelids. In performing operations that require a vertical incision through the lower eyelid, we have observed the height of the lower tarsus to be significantly smaller than shown in previous published reports.l" Therefore, we have undertaken a study in both patients and cadavers to document the height of the lower tarsus to aid in eyelid reconstruction.
SUBJECTS AND METHODS A calibrated Castroviejo caliper was used to measure the vertical height of the lower tarsus in the middle third of the lower eyelid in 23 eyelids of 20 patients submitting to procedures to correct eyelid notching (one case), perform fullthickness lower eyelid biopsy (one case), correct medial ectropion (four cases), and remove basal cell carcinomas (14 cases). In each case a perpendicular incision was made in the middle third of the lower eyelid with a No. 15 Bard-Parker blade full thickness through the eyelid margin. The tarsus was seen as a white glistening structure, in contrast to the darker layers of orbicularis oculi muscle and the fibroelastic lower eyelid retractors (Fig. 1). If this contrast was obscured by initial bleeding, a cotton-tipped applicator with saline was used to clean any blood from the tarsal plate so that tarsal borders
Fig. 1 (Wesley, McCord, and Jones). Vertical incision through lower eyelid after excision of basal cell carcinoma shows ·vertical height of lower tarsus (arrow).
stood out distinctly from the orbicularis oculi muscle and the fibroelastic tissue (Fig. 2). Initially an operating microscope was used in five cases but the magnification did not add any significant accuracy to the measurements, which were recorded to the nearest 0.1 mm. In each case the vertical incision was made through a section of eyelid, which was clinically normal. In the cases involving basal cell carcinoma, -the eyelid tissue was normal also histologically on frozen section. The side of the body, age, sex, and diagnosis of the patients were recorded. For comparison, measurements of the lower tarsus were performed on 24 lower eyelids of 17 cadavers with vertical sections made through the center of the From the Department of Ophthalmology (Drs. I Id fi () Wesley and McCord), and the Department of Anatoower eye i . Magni cation x 4 was my (Dr. Jones), Emory University School of Medi- used in the cadaver studies to perform cine, Atlanta, Georgia. the measurements with a Castroviejo Reprint requests to Ralph E. Wesley, M.D., al b h h d Department of Ophthalmology, Vanderbilt Universi- C iper ecause t e tarsus in t e ca aver ty School of Medicine, Nashville, TN 37232. is less distinct from the pale layers of 102
AMERICAN JOURNAL OF OPHTHALMOLOGY 90:102--105, 1980
HEIGHT OF LOWER EYELID TARSUS
VOL. 90, NO.1
Fig. 2 (Wesley, McCord, and Jones). After blood is sponged from lower eyelid with medial ectropion, vertical height of the tarsus (arrow) is apparent.
103
There was no statistical correlation of smaller tarsus with advancing years. No differences in tarsal height were found according to diagnosis. In cases in which measurements were made from both lower eyelids, all differences were 0.2 mm or less with the exception of a single cadaver difference of 0.4 mm. One patient with bilateral medial ectropion had a 1. O-mm difference. The marginal artery in 20 out of 24 cadaver eyelids could be identified lying anterior to the tarsus at approximately 1 mm above the base of the tarsus. The marginal artery was identified in the corresponding location in the lower eyelids of nearly all our patients. DISCUSSION
orbicularis and lower retractors. Only cadavers with normal appearing eyelids were used in this study. RESULTS
The average vertical height of the lower tarsus in our patients submitting to eyelid procedures was 3.7 mm (S.D. ± 0.3), which was statistically different (P < .05) from the 5- to 7-mm values reported previously. 1-8 The values of the lower tarsus ranged from 3.2 to 5.0 mm, but a lower tarsus greater than 4.0 mm was found in only two of the 23 eyelids measured at surgery. The average value of cadaver lower eyelid tarsus was 3.9 mm with a range of 3.0 to 5.0 mm (S.D. ± 0.5). No average difference was found between right and left eyelids, although one patient with medial ectropion had a right lower tarsus of 4.0 mm and a left lower tarsus of 5.0 mm. In 14 men the value of the lower tarsus was 3.8 mm and the average lower tarsus in nine women was 3.6 mm, which was not statistically different. Additionally, the average age of the women (64 years) was older than that of the men (41 years).
In procedures to reconstruct or repair the lower eyelid, sutures placed through the tarsus, or skeleton, of the lower eyelid bear most of the tension as opposed to sutures passed through skin, orbicularis oculi muscle, conjunctiva, or the fibroelastic lower eyelid retractors just below the tarsus. If a tension-bearing suture intended for the tarsus is inadvertently placed through the lower eyelid retractors or orbicularis oculi muscle instead of the tarsal plate, the wound may later separate, which would result in an eyelid notch or unnecessary scarring of the skin. If a vertical, full-thickness eyelid incision is made through the lower eyelid, the white, glistening tarsus (Figs. 1 and 2) is distinct from the darker orbicularis oculi muscle or lower eyelid retractors. Bleeding after the initial eyelid incision may stain the white tarsus and reduce the contrast with surrounding tissues, but a saline-soaked, cotton-tipped applicator can be used to clean blood from the tarsus to restore contrast. By visualizing the tarsus at surgery, at least two tension-bearing sutures can be placed through the tarsus and a deep stitch
104
AMERICAN JOURNAL OF OPHTHALMOLOGY
through the gray line (mucocutaneous junction) will pass through the tarsus for additional support. The average value of the lower tarsus in our patients of 3.7 mm (± 0.3) is significantly different both surgically and statistically (P < .05) from the 5 to 7 mm described in previous reports.!" None of these sources indicated how a determination was performed. In all but two of our 23 patients the vertical height of the lower tarsus was 4.0 mm or less. One patient with medial ectropion had a left tarsus of 5.0 mm; the oposite eyelid with a similar clinical appearance measured only 4.0 mm. None of the other patients with medial ectropion had an unusually large tarsus. No correlation of tarsus size by age, sex, or diagnosis was shown. The average value of 3.9 mm (S.D. +0.5) found in cadavers was not statistically different than that in our patients. The larger variation of measurements in cadavers may be the result of varing states of hydration. Some of the larger estimates of the tarsus found in previous reports may have come from observing cadaver eyelids. 1 This error of overestimating the tarsus in cadaver eyelids is explained by the lack of contrast between the tarsus and other eyelid tissues after death. In our study x4 magnification was required to delineate tarsus from lower eyelid retractors. Without magnification the entire lower eyelid appeared to be tarsus. Many operations have been described for correction of ectropion and entropion that show the tarsus to be much larger than we have shown. The success of these operations may result not from the various geometric configurations of fullthickness eyelid excision, but rather from the tightening effect on the lower eyelids and possibly the creation of an internal vertical scar that may strengthen the attachment of the lower eyelid retractors to the tarsus.
JULX, 1980
Our finding that the marginal artery lies usually 1 mm above and anterior to the base of the lower tarsus supports the concept that the incision in the CutlerBeard procedure.v" to reconstruct the upper eyelid, should be 5 mm below the lower eyelid margin to preserve the vascular supply to the remaining lower eyelid margin left as the bridge. However, no tarsus will be included in the flap used to reconstruct the upper eyelid, because this incision will be below the base of the lower tarsus. The height of the upper eyelid tarsus was not measured in this study because the upper tarsal height is obvious when everting the upper eyelid and the measurements reported previously of 8 to 12 mm'" correspond with our results. The size of the lower tarsus is not so easily shown by everting the eyelid; however, the conjunctiva over the lower tarsus has a deeper red appearance than the light palpebral conjunctiva over the lower eyelid retractors. Although all our measurements were performed in patients with eyelid disease, in each case the vertical fullthickness incision was performed in an area of the eyelid that was clinically normal and histologically benign. Additionally, the insignificant difference between the height of the tarsus in our patients (average 3.7 mm) and the measurements in cadavers with no eyelid disease (3.9 mm) supports our experience that the height of the lower tarsus, or skeleton of the lower eyelid, is usually 4.0 mm or less. SUMMARY
The vertical height of the lower eyelid tarsus of 20 patients submitting to lower eyelid resections and the lower tarsus of 17 cadavers was 3.7 mm (± 0.3) and 3.9 mm (± 0.5), respectively. The average value found in our patients was statistically different (P < .05) than the values of
VOL. 90, NO. 1
HEIGHT OF LOWER EYEUD TARSUS
5 to 7 mm reported previously. The lower tarsus should be clearly identified in procedures involving eyelid repair or eyelid reconstruction so that tensionbearing sutures can be placed through the tarsus. ACKNOWLEDGMENT
David Myrich, of Storz Instrument Co., provided instrumentation and assistance in this study. REFERENCES 1. Whitnall, S. E.: The Anatomy of the Human Orbit. London, Frowde, Hodder, and Stoughton, 1921, p.147. 2. Warwick, R. (ed.): Eugene Wolffs Anatomy of the Human Eye. Philadelphia, W. B. Saunders and ce., 1976, p. 189. 3. Jones. L. T.: The eyelids. In Jones, L. T., Reeh, M. J., and Wirtschafter, J. D. (eds.): Ophthalmic Anatomy. A Manual With Some Clinical Applica-
105
tions. Rochester, American Academy of'Ophthalmology and Otolaryngology, 1970, p. 50. 4. Jones, L. T., and Wobig, J. L.: Surgery of the Eyelids and Lacrimal System. Birmingham, Aesculapius Publishing Co., 1976, p. 41. 5. Kronfeld, P. C.: The eye. In Davson, H. (ed.): The Gross Anatomy and Embryology of the Eye, 2nd ed., London, Academic Press, 1969, vol. I, p. 35. 6. Brush, J. C. (ed.): Cunningham's Textbook of Anatomy, 9th ed. London, Oxford University Press, 1951, p. 1174. 7. Duke-Elder, S.: The development, form and function of the visual apparatus. In Textbook of Ophthalmology, vol. 1. St. Louis, c. V. Mosby ce., 1944, p. 207. 8. Warwick, R., and Williams, P. L. (eds.): Gray's Anatomy, 35th ed. Philadelphia, W. B. Saunders ce., 1973, p. 1130. 9. Cutler, N. L., and Beard, C.: A method for partial and total upper lid reconstruction. Am. J. Ophthalmol. 39:1, 1955. 10. Smith, B., and Obear, M.: Bridge Hap technique for large upper lid defects, Plast. Reconstr. Surg. 38:45, 1966.
The tarsal plate forms the supporting structure, or skeleton, of the eyelids. In performing operations that require a vertical incision through the lower eyelid, we have observed the height of the lower tarsus to be significantly smaller than shown in previous published reports.l" Therefore, we have undertaken a study in both patients and cadavers to document the height of the lower tarsus to aid in eyelid reconstruction.
SUBJECTS AND METHODS A calibrated Castroviejo caliper was used to measure the vertical height of the lower tarsus in the middle third of the lower eyelid in 23 eyelids of 20 patients submitting to procedures to correct eyelid notching (one case), perform fullthickness lower eyelid biopsy (one case), correct medial ectropion (four cases), and remove basal cell carcinomas (14 cases). In each case a perpendicular incision was made in the middle third of the lower eyelid with a No. 15 Bard-Parker blade full thickness through the eyelid margin. The tarsus was seen as a white glistening structure, in contrast to the darker layers of orbicularis oculi muscle and the fibroelastic lower eyelid retractors (Fig. 1). If this contrast was obscured by initial bleeding, a cotton-tipped applicator with saline was used to clean any blood from the tarsal plate so that tarsal borders
Fig. 1 (Wesley, McCord, and Jones). Vertical incision through lower eyelid after excision of basal cell carcinoma shows ·vertical height of lower tarsus (arrow).
stood out distinctly from the orbicularis oculi muscle and the fibroelastic tissue (Fig. 2). Initially an operating microscope was used in five cases but the magnification did not add any significant accuracy to the measurements, which were recorded to the nearest 0.1 mm. In each case the vertical incision was made through a section of eyelid, which was clinically normal. In the cases involving basal cell carcinoma, -the eyelid tissue was normal also histologically on frozen section. The side of the body, age, sex, and diagnosis of the patients were recorded. For comparison, measurements of the lower tarsus were performed on 24 lower eyelids of 17 cadavers with vertical sections made through the center of the From the Department of Ophthalmology (Drs. I Id fi () Wesley and McCord), and the Department of Anatoower eye i . Magni cation x 4 was my (Dr. Jones), Emory University School of Medi- used in the cadaver studies to perform cine, Atlanta, Georgia. the measurements with a Castroviejo Reprint requests to Ralph E. Wesley, M.D., al b h h d Department of Ophthalmology, Vanderbilt Universi- C iper ecause t e tarsus in t e ca aver ty School of Medicine, Nashville, TN 37232. is less distinct from the pale layers of 102
AMERICAN JOURNAL OF OPHTHALMOLOGY 90:102--105, 1980
HEIGHT OF LOWER EYELID TARSUS
VOL. 90, NO.1
Fig. 2 (Wesley, McCord, and Jones). After blood is sponged from lower eyelid with medial ectropion, vertical height of the tarsus (arrow) is apparent.
103
There was no statistical correlation of smaller tarsus with advancing years. No differences in tarsal height were found according to diagnosis. In cases in which measurements were made from both lower eyelids, all differences were 0.2 mm or less with the exception of a single cadaver difference of 0.4 mm. One patient with bilateral medial ectropion had a 1. O-mm difference. The marginal artery in 20 out of 24 cadaver eyelids could be identified lying anterior to the tarsus at approximately 1 mm above the base of the tarsus. The marginal artery was identified in the corresponding location in the lower eyelids of nearly all our patients. DISCUSSION
orbicularis and lower retractors. Only cadavers with normal appearing eyelids were used in this study. RESULTS
The average vertical height of the lower tarsus in our patients submitting to eyelid procedures was 3.7 mm (S.D. ± 0.3), which was statistically different (P < .05) from the 5- to 7-mm values reported previously. 1-8 The values of the lower tarsus ranged from 3.2 to 5.0 mm, but a lower tarsus greater than 4.0 mm was found in only two of the 23 eyelids measured at surgery. The average value of cadaver lower eyelid tarsus was 3.9 mm with a range of 3.0 to 5.0 mm (S.D. ± 0.5). No average difference was found between right and left eyelids, although one patient with medial ectropion had a right lower tarsus of 4.0 mm and a left lower tarsus of 5.0 mm. In 14 men the value of the lower tarsus was 3.8 mm and the average lower tarsus in nine women was 3.6 mm, which was not statistically different. Additionally, the average age of the women (64 years) was older than that of the men (41 years).
In procedures to reconstruct or repair the lower eyelid, sutures placed through the tarsus, or skeleton, of the lower eyelid bear most of the tension as opposed to sutures passed through skin, orbicularis oculi muscle, conjunctiva, or the fibroelastic lower eyelid retractors just below the tarsus. If a tension-bearing suture intended for the tarsus is inadvertently placed through the lower eyelid retractors or orbicularis oculi muscle instead of the tarsal plate, the wound may later separate, which would result in an eyelid notch or unnecessary scarring of the skin. If a vertical, full-thickness eyelid incision is made through the lower eyelid, the white, glistening tarsus (Figs. 1 and 2) is distinct from the darker orbicularis oculi muscle or lower eyelid retractors. Bleeding after the initial eyelid incision may stain the white tarsus and reduce the contrast with surrounding tissues, but a saline-soaked, cotton-tipped applicator can be used to clean blood from the tarsus to restore contrast. By visualizing the tarsus at surgery, at least two tension-bearing sutures can be placed through the tarsus and a deep stitch
104
AMERICAN JOURNAL OF OPHTHALMOLOGY
through the gray line (mucocutaneous junction) will pass through the tarsus for additional support. The average value of the lower tarsus in our patients of 3.7 mm (± 0.3) is significantly different both surgically and statistically (P < .05) from the 5 to 7 mm described in previous reports.!" None of these sources indicated how a determination was performed. In all but two of our 23 patients the vertical height of the lower tarsus was 4.0 mm or less. One patient with medial ectropion had a left tarsus of 5.0 mm; the oposite eyelid with a similar clinical appearance measured only 4.0 mm. None of the other patients with medial ectropion had an unusually large tarsus. No correlation of tarsus size by age, sex, or diagnosis was shown. The average value of 3.9 mm (S.D. +0.5) found in cadavers was not statistically different than that in our patients. The larger variation of measurements in cadavers may be the result of varing states of hydration. Some of the larger estimates of the tarsus found in previous reports may have come from observing cadaver eyelids. 1 This error of overestimating the tarsus in cadaver eyelids is explained by the lack of contrast between the tarsus and other eyelid tissues after death. In our study x4 magnification was required to delineate tarsus from lower eyelid retractors. Without magnification the entire lower eyelid appeared to be tarsus. Many operations have been described for correction of ectropion and entropion that show the tarsus to be much larger than we have shown. The success of these operations may result not from the various geometric configurations of fullthickness eyelid excision, but rather from the tightening effect on the lower eyelids and possibly the creation of an internal vertical scar that may strengthen the attachment of the lower eyelid retractors to the tarsus.
JULX, 1980
Our finding that the marginal artery lies usually 1 mm above and anterior to the base of the lower tarsus supports the concept that the incision in the CutlerBeard procedure.v" to reconstruct the upper eyelid, should be 5 mm below the lower eyelid margin to preserve the vascular supply to the remaining lower eyelid margin left as the bridge. However, no tarsus will be included in the flap used to reconstruct the upper eyelid, because this incision will be below the base of the lower tarsus. The height of the upper eyelid tarsus was not measured in this study because the upper tarsal height is obvious when everting the upper eyelid and the measurements reported previously of 8 to 12 mm'" correspond with our results. The size of the lower tarsus is not so easily shown by everting the eyelid; however, the conjunctiva over the lower tarsus has a deeper red appearance than the light palpebral conjunctiva over the lower eyelid retractors. Although all our measurements were performed in patients with eyelid disease, in each case the vertical fullthickness incision was performed in an area of the eyelid that was clinically normal and histologically benign. Additionally, the insignificant difference between the height of the tarsus in our patients (average 3.7 mm) and the measurements in cadavers with no eyelid disease (3.9 mm) supports our experience that the height of the lower tarsus, or skeleton of the lower eyelid, is usually 4.0 mm or less. SUMMARY
The vertical height of the lower eyelid tarsus of 20 patients submitting to lower eyelid resections and the lower tarsus of 17 cadavers was 3.7 mm (± 0.3) and 3.9 mm (± 0.5), respectively. The average value found in our patients was statistically different (P < .05) than the values of
VOL. 90, NO. 1
HEIGHT OF LOWER EYEUD TARSUS
5 to 7 mm reported previously. The lower tarsus should be clearly identified in procedures involving eyelid repair or eyelid reconstruction so that tensionbearing sutures can be placed through the tarsus. ACKNOWLEDGMENT
David Myrich, of Storz Instrument Co., provided instrumentation and assistance in this study. REFERENCES 1. Whitnall, S. E.: The Anatomy of the Human Orbit. London, Frowde, Hodder, and Stoughton, 1921, p.147. 2. Warwick, R. (ed.): Eugene Wolffs Anatomy of the Human Eye. Philadelphia, W. B. Saunders and ce., 1976, p. 189. 3. Jones. L. T.: The eyelids. In Jones, L. T., Reeh, M. J., and Wirtschafter, J. D. (eds.): Ophthalmic Anatomy. A Manual With Some Clinical Applica-
105
tions. Rochester, American Academy of'Ophthalmology and Otolaryngology, 1970, p. 50. 4. Jones, L. T., and Wobig, J. L.: Surgery of the Eyelids and Lacrimal System. Birmingham, Aesculapius Publishing Co., 1976, p. 41. 5. Kronfeld, P. C.: The eye. In Davson, H. (ed.): The Gross Anatomy and Embryology of the Eye, 2nd ed., London, Academic Press, 1969, vol. I, p. 35. 6. Brush, J. C. (ed.): Cunningham's Textbook of Anatomy, 9th ed. London, Oxford University Press, 1951, p. 1174. 7. Duke-Elder, S.: The development, form and function of the visual apparatus. In Textbook of Ophthalmology, vol. 1. St. Louis, c. V. Mosby ce., 1944, p. 207. 8. Warwick, R., and Williams, P. L. (eds.): Gray's Anatomy, 35th ed. Philadelphia, W. B. Saunders ce., 1973, p. 1130. 9. Cutler, N. L., and Beard, C.: A method for partial and total upper lid reconstruction. Am. J. Ophthalmol. 39:1, 1955. 10. Smith, B., and Obear, M.: Bridge Hap technique for large upper lid defects, Plast. Reconstr. Surg. 38:45, 1966.