Erecting Prism Attachment for Indirect OphthalmoscopesSchirmer, K.;Shea, M.
doi: 10.1001/archopht.1970.00990030529001pmid: 5442141
Abstract Prismatic inverters are used to erect the inverted image of indirect ophthalmoscopy. Binocular and monocular indirect ophthalmoscopes can be equally well adapted to yield upright imagery. The inverter fits only to the central area of field that is congruous with the handheld lens. With the lens in place for indirect ophthalmoscopy, the image and the surrounding field yield upright imagery. References 1. Kloeti R: Netzhautabloesung . Basel, S. Karger, 1967, p 23. 2. Schepens CL: A new ophthalmoscope demonstration . Trans Acad Ophthal Otolaryng 51:298-301, 1947. 3. Schepens CL, and Pomerantzeff O: The new indirect ophthalmoscope. International Symposium on Retinal Detachment, Houston, June 1965. 4. Donaldson DD: A binocular indirect ophthalmoscope with upright fundus image . Arch Ophthal 71:475-480, 1964.Crossref 5. Schirmer KE: The upright image in indirect ophthalmoscopy . Arch Ophthal 77:67-70, 1967.Crossref
The Influence of Surgical Procedure on Strabismic AmblyopiaVereecken, Erik
doi: 10.1001/archopht.1970.00990030533002pmid: 5442142
Abstract A detailed report is presented on the first published case of a concomitant squint in an adult, with deep amblyopia with eccentric fixation in the left eye, in which operative intervention alone normalized inhibition, fixation and correspondence simultaneously. The mechanism of this normalization is explained. References 1. Böhme G: Ueber die motorische Komponente der exzentrischen Fixation und ihre operative Korrektur . Klin Mbl Augenheilk 130:628-637, 1957. 2. Ehrich W: Der Einfluss der Schieloperation auf den Fixationsort des amblyopen Auges . Klin Mbl Augenheilk 133:846-847, 1958. 3. Cüppers C: Sur l'influence des facteurs moteurs et de mesures opératoires dans l'amblyopie. Read before Journées européennes d'études strabologiques. Parma, Italy, April 26, 1964. 4. Cüppers C: Some reflections on the possibility of altering the pathological fixation act . Ann Roy Coll Surg 38:308-325, 1966. 5. Sevrin G, Decorte H: Chirurgie de déplacement de la fixation excentrique: International Strabismus Symposium, Symposium Giessen, 1966 . Basel, Switzerland, S Karger, 1968. 6. Jacobi KW: Einige bemerkenswerte Fälle von Fixationswandel nach Schieloperationen . Klin Mbl Augenheilk 152:751-757, 1968. 7. Vereecken E, Flynn JT: Amblyopia: I. Diagnosis . J Pediat Ophthal 4:43-54, 1967.
Intraocular Nocardiosis: Report of Three CasesMeyer, Sam L.;Font, Ramon L.;Shaver, Robert P.
doi: 10.1001/archopht.1970.00990030536003pmid: 5309736
Abstract Two new cases of endogenous nocardial endophthalmitis and the first case of postoperative nocardial infection following cataract extraction are reported. The two patients with endogenous infection (cases 2 and 3) clinically presented a paracentral or central chorioretinitis. One of these patients (case 3) died with disseminated nocardiosis. References 1. Bergström, R., et al: Systemic Nocardia Infection , Scand J Resp Dis 47:75-84, 1966. 2. Brine, J.A.S.: Human Nocardiosis: A Developing Clinical Picture , Med J Aust 1:339-342 ( (March) ) 1965. 3. Failes, D., and Posney, K.: Systemic Nocardiosis Presenting as a Breast Abscess , Med J Aust 1:342-344 ( (March) ) 1965. 4. Hathaway, B.M., and Mason, K.N.: Nocardiosis: Study of Fourteen Cases , Amer J Med 32:903-909 ( (June) ) 1962.Crossref 5. King, R.B., et al: Nocardia asteroides Meningitis: A Case Successfully Treated With Large Doses of Sulfadiazine and Urea , J Neurosurg 24:749-751 ( (April) ) 1966.Crossref 6. Murray, J.F., et al: The Changing Spectrum of Nocardiosis: A Review and Presentation of Nine Cases , Amer Rev Resp Dis 83:315-330 ( (March) ) 1961. 7. Cross, M., and Binford, C.H.: Is Nocardia asteroides an Opportunist? , Lab Invest 11:1103-1109 (Nov, (pt 2) ) 1962. 8. Benedict, W.L., and Iverson, H.A.: Chronic Keratoconjunctivitis Associated With Nocardia , Arch Ophthal 32:89-92 ( (Aug) ) 1944.Crossref 9. Henderson, J.W.; Wellman, W.E.; and Weed, L.A.: Nocardiosis of the Eye: Report of Cases , Mayo Clin Proc 35:614-618 ( (Oct) ) 1960. 10. McLean, J.M.: Oculomycosis , Trans Amer Acad Ophthal Otolaryng 67:149-163 ( (March-April) ) 1963. 11. Schardt, W.M.; Unsworth, A.C.; and Hayes, C.V.: Corneal Ulcer Due to Nocardia asteroides , Amer J Ophthal 42:303-305 ( (Aug) ) 1956. 12. Zimmerman, L.E.: Mycotic Keratitis , Lab Invest 11:1151-1160 (Nov, (pt 2) ), 1962. 13. Zimmerman, L.E.: Keratomycosis , Survey Ophthal 8:1-25 ( (Feb) ) 1963. 14. Davidson, S., and Foerster, H.C.: Intraocular Nocardial Abscess, Endogenous , Trans Amer Acad Ophthal Otolaryng 71:847-850 ( (Sept-Oct) ) 1967. 15. Emmons, C.W.; Binford, C.H.; and Utz, J.P.: Medical Mycology , Philadelphia: Lea & Febiger, 1963, p 79. 16. Fine, B.S.: Intraocular Mycotic Infections , Lab Invest 11:1161-1171 (Nov, (pt 2) ) 1962. 17. Fine, B.S., and Zimmerman, L.E.: Exogenous Intraocular Fungus Infections With Particular Reference to Complications of Intraocular Surgery , Amer J Ophthal 48:151-165 ( (Aug) ) 1959. 18. Fine, B.S., and Zimmerman, L.E.: Postoperative Mycotic Endophthalmitis Diagnosed Clinically and Verified Histopathologically , Brit J Ophthal 43:753-758 ( (Dec) ) 1959.Crossref 19. Hogan, J.J.; Thygeson, P.; and Kimura, S.: Uses and Abuses of Adrenal Steroids and Corticotropin , Trans Amer Ophthal Soc 52:145-171, 1954. 20. Moser, R.: Gefahren der Cortisontherapie , Ophthalmologica 123:313-316 ( (May-June) ) 1952.Crossref 21. Woods, A.C.: Uses and Limitations of ACTH and Cortisone in Ophthalmology , Brit J Ophthal 36:401-431 ( (Aug) ) 1952.Crossref 22. Ley, A.P., and Sanders, T.E.: Fungus Keratitis: A Report of Three Cases , Arch Ophthal 56:257-264 ( (Aug) ) 1956.Crossref 23. Mitsui, Y., and Hanabusa, J.: Corneal Infections After Cortisone Therapy , Brit J Ophthal 39:244-250 ( (April) ) 1955.Crossref 24. Thygeson, P.; Hogan, M.J.; and Kimura, S.J.: Cortisone and Hydrocortisone in Ocular Infections , Trans Amer Acad Ophthal Otolaryng 57:64-85 ( (Jan-Feb) ) 1953. 25. Mankowski, Z.T., and Littleton, B.J.: Action of Cortisone and ACTH on Experimental Fungus Infections , Antibiot Chemother 4:253-258 ( (March) ) 1954. 26. Seligmann, E.: Virulence Enhancement of Candida albicans by Antibiotics and Cortisone , Proc Soc Exp Biol Med 83:778-781 ( (Aug-Sept) ) 1953.Crossref 27. Vogel, R.A.; Michael, M., Jr.; and Timpe, A.: Cortisone in Experimental Histoplasmosis , Amer J Path 31:535-543 ( (May-June) ) 1955. 28. Ley, A.P.: Experimental Fungus Infections of the Cornea: A Preliminary Report , Amer J Ophthal 42:59-71 (Oct, (pt 2) ) 1956.
Further Studies on the Pathophysiology of Keratitis Sicca of RolletBrown, Stuart I.
doi: 10.1001/archopht.1970.00990030542004pmid: 5442143
Abstract Observations made in 1936 by Rollet are reconfirmed and elaborated. The factors found to be associated with spot-wise drying of the tear film were reduced tear volume, irregularities of the corneal surface, widened palpebral fissures, and abnormalities of the lid margin which prevented efficient blinking motions. When corneal sensation was normal, this tear-film drying stimulated blinking. However, when drying occurred in patients with reduced corneal sensation, blinking was delayed, the epithelium was desiccated, and erosions could be seen. This form of keratitis sicca was most common in the aged and could occur with a normal tear volume, especially in those patients with wide palpebral fissures. References 1. Marx E: De la sensibilité et du déssechement de la cornée . Ann Oculist 158:774-789, 1921. 2. Rollet J: La couche de liquide pré-cornéenne . Arch Ophthal 53:5-24, 1936. 3. Girard LJ, Soper JW, Sampson WG: Fitting of the lens , in Girard LJ (ed): Corneal Contact Lenses . St. Louis, CV Mosby Co, 1964. 4. Girard LJ: Corneal disiccata. Read before the section on Ophthalmology at the 116th annual convention of the American Medical Association, Atlantic City, NJ, June 19, 1967. 5. Brown SI: in discussion of Baum J, et al: Nature of dellen. Read before the section on Ophthalmology at the 116th annual convention of the American Medical Association, Atlantic City, NJ, June 19, 1967. 6. Brown SI: Clinical studies of the precorneal tear film. Read before the Section of Ophthalmology New York Academy of Medicine, Feb 13, 1967. 7. Cochet P. Bonnet R: L'esthésiologie cornéen, sa mésure clinique, ses variations physiologiques et pathologiques . Clin Ophtal , 1960, pp 2-26. 8. Schirmer O: Studien zur Physiologie und Pathologie der Tränenabsonderung und Tranenabuhr . Graefe Arch Ophthal 56:197, 1903.Crossref 9. Schweitzer NMJ: A fluorescein colored polygonal pattern in the human cornea . Arch Ophthal 77:548, 1967.Crossref 10. Brown SI, Dervichian DG: The oils of the meibomian glands . Arch Ophthal 82:537-540, 1969.Crossref 11. Brown SI, Dervichian DG: Hydrodynamics of blinking . Arch Ophthal 82:541-547, 1969.Crossref
The Radioactive Phosphorus Uptake Test in Diagnosis of Uveal MelanomaHagler, William S.;Jarrett, William H.;Humphrey, William T.
doi: 10.1001/archopht.1970.00990030548005pmid: 5442144
Abstract Radioactive phosphorus uptake studies have proved useful in the differential diagnosis of mass lesions of the posterior uveal tract. The authors describe a modification in technique, stressing precise localization of the lesion by indirect ophthalmoscopy and accurate positioning of the counting probe directly over the lesion. There were 41 posterior choroidal lesions studied with no false positive results and only two false negative tests. Hemangiomas, choroidal hematomas, and benign retinal vascular tumors can be distinguished from malignant lesions by means of this test. The radioactive phosphorus uptake test was not found to be helpful in iris tumors. References 1. Ferry AP: Lesions mistaken for malignant melanoma of the posterior uvea . Arch Ophthal 72:463-469, 1964.Crossref 2. Howard GM: Erroneous clinical diagnoses of retinoblastoma and uveal melanoma . Trans Amer Acad Ophthal Otolaryng 73:199-203, 1969. 3. Blodi FC, Roy PE: The misdiagnosed choroidal melanoma . Canad J Ophthal 2:209-211, 1967. 4. Font RL, Spaulking AG, Zimmerman LE: Diffuse malignant melanoma of the uveal tract: A clinicopathologic report of 54 cases . Trans Amer Acad Ophthal Otolaryng 72:877-893, 1968. 5. Reese AB, Howard GM: Flat uveal melanomas . Amer J Ophthal 64:1021-1028, 1967. 6. Thomas CI, Korhmer JS, Storaasli JP: Detection of intraocular tumors with radioactive phosphorus . Arch Ophthal 47:276-286, 1952.Crossref 7. Goldberg B, Tabowitz D, Kara GB, et al: The use of P 32 in the diagnosis of ocular tumors . Arch Ophthal 65:196-211, 1961.Crossref 8. Thomas CI, Krohmer JS, Storaasli JP, et al: Detection of intraocular tumors by the use of radioactive phosphorus . Amer J Ophthal 38:93-100, 1954. 9. Thomas CI, Bovington MS, MacIntyre WJ, et al: Experimental investigation on uptake of radioactive phosphorus in ocular tumors . Arch Ophthal 61:464-490, 1959.Crossref 10. Thomas CI, Storaasli JP, Friedell HL: Radioactive phosphorus in the detection of intraocular neoplasms: A report of 150 cases . Amer J Roentgen 95:935-941, 1965.Crossref 11. Thomas CI, Krohmer JS: A transilluminator for use with the curved geiger counter: An aid to localization of posterior intraocular neoplasms . Arch Ophthal 55:413-414, 1956.Crossref 12. Dunphy EB, and Selverstone B: Uptake of radioactive phosphorus by normal and neoplastic ocular tissues . Amer J Ophthal 36:774-776, 1953. 13. Dunphy EB, Dreisler KK, Cadigan JB, et al: The uptake of radioactive phosphorus by intraocular neoplasms . Amer J Ophthal 37:45-54, 1954. 14. Dunphy EB: The role of radioactive phosphorus in the diagnosis of ocular malignancy . Trans Ophthal Soc UK 76:137-152, 1956. 15. Dunphy EB, Dowling JL, Scott A: Experience with radioactive phosphorus in tumor detection . Trans Amer Ophthal Soc 54:289-299, 1956. 16. Leopold IH, Keates EU: Role of isotopes in diagnosis of intraocular neoplasma . Trans Amer Ophthal Soc 62:86-99, 1964. 17. Carmichael PL, Leopold IH: The radioactive phosphorus test in ophthalmology . Amer J Ophthal 49:484-488, 1960. 18. Eisenberg IJ, Leopold IH, Sklaroff D: Use of radioactive phosphorus in detection of intraocular neoplasms . Arch Ophthal 51:633-641, 1954.Crossref 19. Temer IS, Leopold IH, Eisenberg IJ: The radioactive phosphorus uptake test in ophthalmology . Arch Ophthal 55:52-83, 1956.Crossref 20. Owens WC, King JH, Wells HS: Radioactive phosphorus for the detection of intraocular tumors . Amer J Ophthal 41:507-513, 1956. 21. O'Rourke JF, Patton H, Bradley R: Fundamental limitations of radiophosphorus counting methods used for detection of intraocular neoplasm . Arch Ophthal 57:730-738, 1957.Crossref 22. O'Rourke JF, Patton H, Bradley R: A study of the uptake of P32, Zn65, and I131 albumin by experimental malignant melanoma . Amer J Ophthal 44:190-196, 1957. 23. O'Rourke JF, Collins E: P32 localization of malignant melanoma of the posterior choroid . Arch Ophthal 63:801-811, 1960.Crossref 24. Bettman JW, Fellows V: A scintillation counter for the diagnosis of intraocular melanomas . Amer J Ophthal 39:170-177, 1955. 25. Palin A, Tudway RC: The use of radioactive isotopes in diagnosis of intraocular malignancy . Trans Ophthal Soc UK 75:281-299, 1955. 26. Donn A, McTigue JW: The radioactive phosphorus uptake test for malignant melanoma of the eye: A study of 40 consecutive cases of suspected intraocular malignant melanomas . Arch Ophthal 57:668-671, 1957.Crossref 27. Shapiro I: Radioactive phosphorus in differential diagnosis of ocular tumors: Special reference to results of University of Michigan study, July 1954-May 1956 . Arch Ophthal 57:14-17, 1957.Crossref
Butterfly—Shaped Pigment Dystrophy of the FoveaDeutman, August F.;van Blommestein, Johann D. A.;Henkes, Harold E.;Waardenburg, Petrus J.;Driest, Else Solleveld-van
doi: 10.1001/archopht.1970.00990030558006pmid: 5442145
Abstract Four of five white brothers and a son of one of them were found to have peculiar, bilateral, butterfly-shaped pigment dystrophy of the fovea. Their cases have been followed up since 1965. Three of them have normal visual acuity, and two have a slightly diminished visual acuity. Four of the five affected individuals have a pathological electro-oculogram, which reflects a diffuse abnormality of the retina. At funduscopy only two of the five affected subjects have peripheral alterations. Probably this condition is transmitted as an autosomal dominant. References 1. Hagedoorn, A., and Van Den Bosch, C.: A Double-Projection Campimeter , Amer J Ophthal 40:891-893, 1955. 2. Arden, G.B.; Barrada, A.; and Kelsey, J.H.: New Clinical Test of Retinal Function Based Upon the Standing Potential of the Eye , Brit J Ophthal 46:449-467, 1962.Crossref 3. Kelsey, J.H.: Clinical Electro-oculography , Brit J Ophthal 50:438-439, 1966.Crossref 4. Kelsey, J.H.: Variations in the Normal Electro-oculogram , Brit J Ophthal 51:44-49, 1967.Crossref 5. Henkes, H.E.; Denier Van Der Gon, J.J.; and Van Marle, G.W.: Electro-oculography: A Semiautomatic Recording Procedure , Brit J Ophthal 52:122-126, 1968.Crossref 6. Henkes, H.E.: Electro-oculography as a Diagnostic Aid in Phenothiazin Retinopathy , Trans Ophthal Soc UK 87:285-287, 1967. 7. Oosterhuis, J.A., and Lammens, A.J.J.: Fluorescein Photography of the Ocular Fundus , Ophthalmologica 149:210-220, 1965.Crossref 8. Gruetzner, P.: Typische Erworbene Farbensinnstörungen bei Heredodegenerativen Makulaleiden , Klin Mbl Augenheilk 136:582-583, 1960. 9. François, J.; De Rouck, A.; and Fernandez-Sasso, D.: Electro-oculography in Vitelliform Degeneration of the Macula , Arch Ophthal 77:726-733, 1967.Crossref 10. François, J.; De Rouck, A.; and Fernandez-Sasso, D.: L'Electro-oculographie dans les kystes vitelliformes de la macula , Bull Soc Belg Ophtal 143:547-552, 1966. 11. Krill, A.E., et al: Hereditary Vitelliruptive Macular Degeneration , Amer J Ophthal 61:1405-1415, 1966. 12. Deutman, A.F.: Electro-oculography in Families With Vitelliform Dystrophy of the Fovea: Detection of the Carrier State , Arch Ophthal 81:305-316, 1969.Crossref 13. Arden, G.B., and Kolb, H.: Electrophysiological Investigations in Retinal Metabolic Disease: Their Range and Application , Exp Eye Res 3:334-347, 1964.Crossref 14. Gouras, P., and Carr, R.E.: Light-Induced DC Responses of Monkey Retina Before and After Central Retinal Artery Interruption , Invest Ophthal 4:310-317, 1965. 15. Klien, B.A., and Krill, A.E.: Fundus Flavimaculatus: Functional and Histopathological Observations , Amer J Ophthal 64:3-23, 1967. 16. Craandijk, A., and Aan de Kerk, A.L.: Retinal Photography Using Panchromatic and Orthochromatic Films , Brit J Ophthal 53:568-573, 1969.Crossref 17. Waardenburg, P.J.: Genetics and Ophthalmology , Assen, Netherlands: Royal van Gorcum, 1963. 18. Franceschetti, A.; François, J.; and Babel, J.: Les Hérédodégénérescences Chorio-rétiniennes , Paris: Masson et Cie, 1963. 19. François, J.: Vitelliform Degeneration of the Macula , Bull NY Acad Med 44:18-27, 1968. 20. Morse, P.H., and MacLean, A.: Fluorescein Fundus Studies in Hereditary Vitelliruptive Macular Degeneration , Amer J Ophthal 66:485-494, 1968. 21. Sjögren, H.: Dystrophia Reticularis Laminae Pigmentosae Retinae , Acta Ophthal 28:279-295, 1950.Crossref 22. Deutman, A.F., and Rümke, A.M.L.: Reticular Dystrophy of the Retinal Pigment Epithelium , Arch Ophthal 82:4-9 ( (July) ) 1969.Crossref 23. Loewenstein, A., and Steel, J.: Special Case of Melanosis Fundi: Bilateral Congenital Group Pigmentation of the Central Area , Brit J Ophthal 25:417-423, 1941.Crossref 24. Chan, E.: Melanosis Retinae , Chinese Med J 69:431-432, 1951. 25. Forgacs, J., and Bozin, I.: Manifestation familiale de Pigmentations Groupées de la Région Maculaire , Ophthalmologica 152:364-368, 1966.Crossref
Meridional Refractometry: II. Data ReductionBrubaker, Richard F.;Reinecke, Robert D.;Newman, Joel S.
doi: 10.1001/archopht.1970.00990030570007pmid: 5442146
Abstract Three methods for simplifying the solution of the equations used in meridional refractometry are outlined: solution by time-sharing, multiple-access digital computers; solution by special-purpose analogue computer; and solution by nomogram. The advantages and the disadvantages of each method are discussed. It is suggested that a special-purpose analogue computer is the most feasible data reduction device for meridional refractometry. References 1. Brubaker, R.F.; Reinecke, R.D.; and Copeland, J.C.: Meridional Refractometry: I. Derivation of Equations , Arch Ophthal 81:849-852 ( (June) ) 1969.Crossref
Acquired Sixth-Nerve Paresis in ChildrenRobertson, Dennis M.;Hines, J. Douglas;Rucker, C. Wilbur
doi: 10.1001/archopht.1970.00990030574008pmid: 5467504
Abstract In a review of 133 cases of isolated acquired sixth-nerve paresis in the pediatric age group, six etiologic categories were analyzed separately. More than a third of the cases were due to tumor; in the cases of tumor it was frequently noted that there was a history of trauma or there were findings suggestive of an infectious process. Of the ten cases with Gradenigo's syndrome, three were later discovered to have tumor. The presence of chronic papilledema and fifth-nerve involvement suggested tumor. Though the prognosis for the tumor group was poor, the patients whose disorder was due to trauma or inflammation often had complete spontaneous resolution of the nerve paresis. References 1. Rucker CW: Paralysis of the third, fourth and sixth cranial nerves . Amer J Ophthal 46:787-794, 1958. 2. Rucker CW: The causes of paralysis of the third, fourth and sixth cranial nerves . Amer J Ophthal 61:1293-1298, 1966. 3. Goldberg RB, Patz A: Abducens nerve palsy: Following saddle block anesthesia . Obstet Gynec 3:192-194, 1954. 4. Knox DL, Clark DB, Schuster FF: Benign VI nerve palsies in children . Pediatrics 40:560-564, 1967.
The Matsui Color Fluorescein Angiography Technique: Adaptation to the Zeiss Fundus CameraHendrickson, Phillip H.;Oniki, Shinobu;Elliott, James H.
doi: 10.1001/archopht.1970.00990030580009pmid: 5442147
Abstract Color fluorescein angiography has been refined by Dr. Kohji Matsui who has employed readily-available Kodak Wratten filters and Kodak film to obtain more natural fundus color, while retaining excellent excitation of fluorescein. The authors have adapted the Matsui technique to the Zeiss fundus camera to produce color fluorescein angiograms which we feel will be valuable in differentiating between true and pseudofluorescence in fluorescein angiography. References 1. Novotny HR, Alvis DL: A method of photographing fluorescence in circulating blood in the human retina . Circulation 24:82-86, 1961.Crossref 2. Haining WM, Lancaster RC: Advanced techniques for fluorescein angiography . Arch Ophthal 79:10-15, 1968.Crossref 3. Hodge JV, Clement RS: Improved method for fluorescence angiography of the retina . Amer J Ophthal 61:1400-1404, 1966. 4. Shikano S, Shimizu K: Atlas of Fluorescence Fundus Angiography . Philadelphia, WB Saunders Co, 1963. 5. Matsui K, Oka Y, Matsui T: Fluorescein fundus angiography in color . Acta Soc Ophthal Jap 73:653-658, 1969.
Anatomic and Radiographic Analysis of the Optic Canal and Orbital ApexPotter, Guy D.;Trokel, Stephen L.
doi: 10.1001/archopht.1970.00990030584010pmid: 5442148
Abstract Hypocycloidal tomograms were obtained at every millimeter of a cadaver head positioned so that the axis of the optic canal was perpendicular to the radiographic film. Without change of position, the head was frozen and sliced. Four 1-mm thick sections of the optic canal and orbital apex were obtained. A direct comparison between the contact radiograph of each anatomic section was made and its corresponding tomogram taken when the head was intact, pointing out the anatomic structures. On the tomogram at the orbital end of the optic canal, an artifactual shadow cast by the thick heavy optic strut was noted. An artifactual shadow at the orbital apex appearing to close the superior orbital fissure was noted also; this artifactual shadow is cast by the lateral wall of the orbit. References 1. Potter GD, Trokel SL: Tomography of the optic canal . Amer J Roentgen 106:530-535, 1969.Crossref