1.ANATOMY OF ORBIT AND CONGENITAL ANOMALIES

2. ANATOMY OF ORBIT 3. SIZE, SHAPE AND RELATIONS OF BONY ORBIT The two bony orbits are quadrangular truncated pyramids These are situated between the anterior cranial fossa above and the maxillary sinuses below. Each orbit is formed by seven bones- frontal, ethmoid, lacrimal, palatine, maxilla, zygomatic and sphenoid. 4. The medial walls of the two orbits are parallel to each other. They are in contact with the ethmoid and sphenoid sinuses, which separate the orbits from the nasal cavities. The lateral wall of each orbit lies at an angle of 45 degree to the medial wall. The lateral walls of the two orbits are at 90 to each other. 5. The lateral wall separates the orbit from the middle cranial fossa posteriorly and the muscular temporal fossa anteriorly The depth of the orbit is 42 mm along the medial wall and 50 mm along the lateral wall. The base of the orbit is 40 mm in width and 35 mm in height. 6. The intra-orbital width i.e. the distance between the medial margins of the right and left orbits is 25 mm. The extraorbital width, i.e. the distance between the right and left lateral orbital margins is 100 mm 7. The relationship between the height and width of the orbit is expressed by the orbital index. Orbital index = (Height/Width) x 100. This index shows racial variation. Races having an orbital index greater than 89 are termed megasenes (e.g. orientals). 8. Mesosenes (e.g. Caucasians) have an orbital index between 83 and 89. Blacks with an index of less than 83 are termed microsenes. The volume of each orbit is about 29 ml. The ratio between the volume of the orbit and of the eyeball is 4.5:1 9. WALLS OF THE ORBIT The bony orbit has four walls: medial wall, lateral wall, roof and floor. These four walls meet at the superior internal, superior external, inferior internal and inferior external angles of the orbit. 10. Medial Wall It is quadrilateral In shape It is formed (from front to back) by the- Frontal process of the maxilla Lacrimal bone Orbital plate of the ethmoid bone Body of the sphenoid bone 11. The anterior part of the medial wall bears the lacrimal sac fossa, which is continuous inferiorly with the nasolacrimal canal The lacrimal fossa is bounded anteriorly by the anterior lacrimal crest of the maxillary bone and posteriorly by the posterior lacrimal crest of the lacrimal bone. 12. Medial to the lacrimal fossa lie the anterior ethmoidal sinuses in the upper part and middle meatus of the nose in the lower part Lacrimal sac along with its fascia lies in the lacrimal fossa. 13. Just behind the posterior lacrimal crest following structures have their attachment- Horner's muscle (lacrimal fibres of the orbicularis) Septum orbitale Check ligament of the medial rectus muscle 14. Relations of the medial wall- Medial to the medial wall (towards the nose) lie anterior ethmoidal air sinuses, middle meatus of nose, middle and posterior ethmoidal sinuses and sphenoidal air sinus. 15. The orbital surface of the medial wall is related to superior oblique muscle in the upper part near the roof and medial rectus muscle in the middle part. In between these two muscles lie the anterior ethmoidal nerve, posterior ethmoidal nerve, infratrochlear nerve and terminal branch of the ophthalmic artery. 16. Clinical applications of the medial wall- The medial orbital wall is the thinnest wall of the orbit. This accounts for ethmoiditis being the commonest cause of orbital cellulitis, especially in children. 17. The medial wall is frequently eroded by chronic inflammatory lesions, cysts and neoplasms that originate in the adjacent air sinuses. It is easily fractured during injuries as well as during orbitotomy operations. 18. During surgery along this wall, haemorrhage is most troublesome due to injury to ethmoidal vessels. In addition, the medial palpebral, frontal and dorsal nasal arteries pass forward near the medial wall. The medial wall can be easily visualised with routine PA radiographs of the orbit. 19. Inferior orbital wall (floor) It is triangular in shape. It is the shortest of all the walls. It is formed by three bones: Orbital surface of the maxillary bone medially Orbital surface of the zygomatic bone laterally Palatine bone posteriorly 20. The posterior part of the floor of the orbit is separated from the lateral wall by the inferior orbital fissure. This fissure is continuous anteriorly with the infraorbital groove which extends anteriorly as a canal. 21. The canal opens at the infraorbital foramen located Just below the infraorbital rim The foramen transmits the infraorbital nerve, the infraorbital artery and the infraorbital vein (which connects the inferior ophthalmic vein to the facial vein) 22. Relations of the inferior wall- Below it is related to maxillary air sinus and palatine air cells. Above it is related to inferior rectus muscle, inferior oblique muscle and nerve to inferior oblique. 23. Clinical applications of the floor- The orbital floor being quite thin is commonly involved in 'blow-out fractures' and is easily invaded by tumours of the maxillary antrum. The floor of the orbit is best visualised with standard posteroanterior radiographs. 24. The orbital floor can be approached by inferior orbitotomy (antral approach) easily. However, the utility of this approach is limited as only a small proportion of tumours are found in this area. 25. Lateral wall It is triangular in shape It is formed- Anteriorly by the zygomatic bone Posteriorly by the greater wing of the sphenoid bone 26. On the posterior part of the lateral wall there is a small bony projection (spina recti lateralis) which gives origin to a part of the lateral rectus muscle. 27. More anteriorly, the wall is marked by the zygomatic groove and foramina (which are traversed by the zygomatic nerve and vessels) On the anterior part of the wall there is a projection, the lateral orbital tubercle of Whitnall. 28. It gives attachment to the check ligament of the lateral rectus muscle, and to the suspensory ligament of the eyeball. The lateral wall posteriorly is separated from the roof by the superior orbital fissure and from the floor by the inferior orbital fissure 29. Relations of the lateral wall- Laterally, the lateral wall separates the orbit from temporal fossa anteriorly and from the middle cranial fossa posteriorly . Medially, i.e. its orbital surface is related to lateral rectus, lacrimal nerve and vessels, zygomatic nerve and the communication between zygomatic and lacrimal nerves. 30. Clinical applications of lateral wall- The lateral wall of the orbit protects only the posterior half of the eyeball. The anterior half of globe is not covered by bone on the lateral side. Hence palpation of retrobulbar tumours is easier from the lateral rather than from the nasal side of the eyeball. 31. Because of its advantageous anatomical position a lateral orbital surgical approach is popular. Further, the lateral wall is almost devoid of foramina, so its anterior portion can be broached without serious haemorrhage (zygomatic-temporal vessels usually do not pose a problem). 32. However, the lateral rim of the orbit, which is the forward extension of the lateral wall, is the strongest portion of the orbit and needs to be sawed open in lateral orbitotomy. 33. Once this bone flap has been turned, the surgeon has direct access to the superolateral, inferolateral and retrobulbar quadrants of the orbit. Since these quadrants are the common sites of orbital tumours, the surgical anatomy of this area is important. 34. Roof It is triangular in shape It is formed mainly by the orbital plate of the frontal bone. Behind this, it is formed by the lesser wing of sphenoid. The anterolateral part of the roof has a depression called the fossa for the lacrimal gland. 35. It is usually quite smooth but may be pitted by the attachments of the suspensory ligament of the lacrimal gland. The fovea for the pulley of the superior oblique (trochlear fossa) is a small depression situated close to the orbital margin, at the junction of the roof and the medial wall. 36. Relations of the roof- Above the roof is related to the frontal lobe of cerebrum and meninges Below the roof are periorbita, frontal nerve, levator palpebrae superioris. superior rectus, superior oblique, trochlear nerve and lacrimal gland 37. At the junction of the roof and the medial wall are the anterior and posterior ethmoidal canals. At the junction of roof with lateral wall is a gap posteriorly, the superior orbital fissure. 38. Clinical applications of roof- The superior wall is rather thin throughout its whole extent and the periorbita easily peels away from its undersurface. A sharp object like walking stick or umbrella, introduced into the orbit through the upper lid penetrates the roof and may damage the frontal lobe. 39. On the cranial side, the dura can be lifted almost easily. As the roof is perforated neither by major nerves nor by blood vessels, it can be easily nibbled away in transfrontal orbitotomy. 40. BASE OF ORBIT The anterior open end of the orbit is referred to as base. It is bounded by the orbital margins The margins are formed by a ring of compact bone. It gives attachment to the septum orbitale The orbital margin can be described under four parts:- 41. Superior orbital margin- It is formed entirely by the orbital arch of the frontal bone. Its lateral two-thirds is sharp and the medial one-third is rounded. Junction of the two parts is the highest point of the orbital arch and here lies the supraorbital notch 42. Which transmits the supraorbital nerve and artery. About 10 mm medial to the supraorbital notch is the supratrochlear groove Which transmits supratrochlear nerve and artery. 43. Lateral orbital margin- It is the strongest and is formed by zygomatic process of the frontal bone and the zygomatic bone. It does not reach as far anterior as the medial margin and thus anterior half of the globe is not protected by the bone laterally 44. Inferior orbital margin- It is formed by the zygomatic bone laterally and maxilla medially, almost in equal proportion. It is slightly raised than the floor. Medially it becomes continuous with the anterior lacrimal crest. 45. The infraorbital foramen transmitting infraorbital nerves and vessels is situated 4-5 mm below the orbital margin in line with the supraorbital foramen. 46. Medial orbital margin- Below it is formed by the anterior lacrimal crest of the frontal process of maxilla and above by the frontal bone. Its upper part becomes continuous with the posterior lacrimal crest. 47. APEX OF ORBIT Orbital apex is the posterior end of the orbit. Here the four orbital walls converge. The apex has two orifices: the optic canal and the superior orbital fissure which are situated in the sphenoid bone (where the body, greater wing and lesser wing meet each other) 48. Optic canal- It connects the orbit to the middle cranial fossa. It transmits the optic nerve (surrounded by meninges) and the ophthalmic artery. 49. Its average length is 6-11 mm (lateral wall is shortest and medial wall is longest). Tumours such as optic nerve glioma and meningioma may lead to unilateral enlargement of the optic canal, which may be detected on X-ray films. 50. Superior orbital fissure- It is a comma shaped aperture in the orbital cavity. It is bounded by lesser and greater wing of the sphenoid. It is situated lateral to the optic foramen at the orbital apex. The fissure is divided into upper, middle and lower parts by the common tendinous ring (for origin of the recti). 51. The structures passing through the upper and lateral part are the lacrimal and frontal nerves (branches of ophthalmic division of Vth nerve),trochlear nerve, superior ophthalmic vein and recurrent branch of the ophthalmic artery. 52. The middle part of the fissure (within tendinous ring) transmits the superior and inferior divisions of the oculomotor nerve, the nasociliary branch of the ophthalmic division of the trigeminal nerve and the abducent nerve. The lower and medial part of the fissure transmit the inferior ophthalmic vein 53. PERIORBITA The periosteum lining the surface of the orbital bones is called the periorbita. Generally it is loosely adherent to bone. However, it is firmly adherent at the orbital margin, superior and inferior orbital fissures, the optic canal, the lacrimal fossa and at the sutures. 54. At the orbital margin periorbita is thickened to form the arcus marginale to which the septum orbitale is attached. At the posterior lacrimal crest the periorbita splits into two layers which reunite at the anterior lacrimal crest. 55. These two layers enclose the lacrimal sac (in the form of lacrimal fascia). At the apex of orbit, the periorbita is thickened to form the common tendinous ring of Zinn. 56. ORBITAL FASCIA It is a complex interwoven thin connective tissue membrane joining the various intraorbital contents. It can be described under the heads of fascia bulbi, muscular sheaths, intermuscular septa, membranous expansions of the extraocular muscles, and ligament of Lockwood. 57. Fascia bulbi- Fascia bulbi, or Tenon's capsule, envelops the globe from the limbus to the optic disc Its inner surface is well defined and lies in close contact with sclera to which it is connected by fine trabeculae. 58. Globe and the capsule move together in the surrounding fat. The outer surface of the fascia bulbi lies in contact with orbital fat posteriorly and with subconjunctival tissue anteriorly with which it merges near the limbus. 59. Tenon's capsule is separated from the sclera by episcleral space (Tenon's space). which can be readily injected. The lower part of the fascia bulbi is thickened and takes part in the formation of a sling or hammock on which the globe rests (suspensory ligament of Lockwood). 60. Around the distal end of optic nerve the fascia is fused with the dural sheath of the optic nerve. Fascia bulbi is pierced posteriorly by the optic nerve, ciliary nerves and vessels, just behind the equator by venae vorticosae, and anteriorly by six extraocular muscles; where it becomes continuous with the fascial sheaths of these muscles. 61. Fascial sheaths of extraocular muscles- At the points where the fascia bulbi is pierced by an extraocular muscle it sends a tubular reflection, which clothes the muscles like a glove. 62. Fascial expansions of extraocular muscles- The muscular sheath of each extraocular muscle sends expansions to the surrounding structures. Fascial expansions of lateral and medial rectus muscles are strong 63. Which are attached to orbital tubercle on the zygomatic bone and to the lacrimal bone, respectively. These are also called lateral and medial check ligaments. 64. Rectus muscle pulleys of connective tissue and some smooth muscle fibres are located close to the equator of globe. These are suspended from the orbital walls through which the rectus muscles pass These pulleys become the functional origin of the muscles 65. Thus effectively modify the direction of pull of rectus muscles. These are stabilized by septa which are attached to fascia bulbi, intermuscular septa and periorbita Expansion of superior rectus muscle is attached to the levator palpebrae superioris. 66. This attachment ensures synergic action of the two muscles. Thus, when the superior rectus makes the eye look up, the upper lid is also raised. In maximal levator resection for ptosis, hypotropia can be induced if these connections are not severed. 67. An expansion from the inferior rectus muscle is attached to the capsulopalbebral fascia. An expansion from the superior oblique passes up to the trochlea. An expansion from the inferior oblique passes to lateral part of the roof of the orbit. 68. From the anterior end of the expansion of each extraocular muscle, a fibrous band passes to be attached to the conjunctival culde-sac. These connections account for the retraction of the conjunctival sac when these muscles contract. 69. Suspensory ligament of Lockwood- It is a thickened sling or hammock of fascial sheath It extends from the posterior lacrimal crest to the lateral orbital tubercle, on which rests the eyeball. 70. It is formed by fusion of expansions from the muscular sheaths of the medial rectus, inferior oblique, inferior rectus and lateral rectus muscle joined with the thickened inferior part of Tenon's capsule. 71. Superior transverse ligament of the Whitnall - It is a thickened band of orbital fascia It extends from the trochlear pulley to the lacrimal gland and its fossa. It is formed by a condensation of the superior sheaths of the levator muscle 72. Which joined medially by the sheath of the reflected tendon of superior oblique muscle. It forms a true check ligament of the levator muscle. 73. Suspensory ligaments of the fornices- Superior suspensory ligament of the fornix is formed by the continuation forward of the fibrous tissue between the superior rectus and levator muscles to the upper fornix. 74. During ptosis surgery, if this ligament is cut fornix conjunctiva can prolapse. Inferior suspensory ligament of the fornix is formed by the continuation forward up to the inferior fornix of the fibrous tissue of lower lid retractors 75. Orbital septa of elastic and collagenous tissue- These septa pass inward from the periobita to fascia bulbi Such septa also pass to and between the extraocular muscles and provide specific supportive channels for the ophthalmic veins 76. Intermuscular septa/membrane- The sheaths of the four rectus muscles are joined to each other by a fascial membrane called the intermuscular septum. This membrane divides the orbital cavity and orbital fat into a central and a peripheral part. 77. ORBITAL FAT & RETICULAR TISSUE Most of the orbital cavity is occupied by orbital fat Which extends from the optic nerve to the orbital wall and from the apex of the orbit to the septum orbitale. The fat lobules lie in the interstices of a web of reticular tissue called the orbital reticulum 78. This tissue is the supporting framework of the orbital fat, anchoring it to the orbital fascia The orbital fat is divided into central and peripheral parts by the intermuscular septa. 79. Posteriorly, where there is no intermuscular septa, the peripheral and central fat pads are continuous with each other. The peripheral orbital fat consists of four lobules- Superomedial, superolateral, inferomedial and inferolateral. 80. Benign encapsulated tumours do not alter the normal structure of reticular tissue and fat except that these structures are under great pressure and when the periorbita has been opened, bulge more persistently into the operative field. 81. However, in case of malignant tumours and infiltrative lesions like pseudotumours and endocrine exophthalmos this basic matrix may alter depending on the nature and duration of the lesion. 82. The orbital fat and its reticular tissue are not as inert as is commonly assumed. At times they may become very reactive. Therefore, lesser the disturbance of these structures during orbitotomy, the better the functional and cosmetic results. 83. OPENINGS INTO THE ORBITAL CAVITY Orbital Opening- The orbital opening lies anteriorly About onesixth of the eye is exposed The remainder is protected by the walls of the orbit. 84. Supraorbital Notch (Foramen)- The supraorbital notch is situated on the superior orbital margin It transmits the supraorbital nerve and blood vessels. 85. Infraorbital Groove and Canal- The infraorbital groove and canal are situated on the floor of the orbit in the orbital plate of the maxilla They transmit the infraorbital nerve (a continuation of the maxillary nerve) and blood vessels. 86. Nasolacrimal Canal- The nasolacrimal canal is located anteriorly on the medial wall It communicates with the inferior meatus of the nose It transmits the nasolacrimal duct 87. Inferior Orbital Fissure- The inferior orbital fissure is located posteriorly between the maxilla and the greater wing of the sphenoid It transmits the maxillary nerve and its zygomatic branch, the inferior ophthalmic vein, and sympathetic nerves 88. Superior orbital fissure- It is located posteriorly between the greater and lesser wings of the sphenoid It transmits the lacrimal nerve, frontal nerve, trochlear nerve ,oculomotor nerve (upper and lower divisions),abducent nerve, the nasociliary nerve, and the superior ophthalmic vein. 89. Optic Canal- The optic canal is located posteriorly in the lesser wing of the sphenoid It transmits the optic nerve and the ophthalmic artery 90. Zygomaticotemporal and Zygomaticofacial Foramina- These are two small openings in the lateral wall They transmit the zygomaticotemporal and the zygomaticofacial nerves, respectively. 91. Anterior and Posterior Ethmoidal Foramina- The ethmoidal foramina are located on the medial wall in the ethmoid bone They transmit the anterior and posterior ethmoidal nerves, respectively. 92. SURGICAL SPACES IN THE ORBIT The orbit is divisible into a number of spaces. These are of importance as most orbital tumours tend to remain within the space in which they are formed (unless they are large or malignant or unless they represent an infiltrative process such as pseudotumours) 93. Therefore, a knowledge of the main compartments of the orbit and their boundaries helps the surgeon in choosing the most direct approach to the tumour From the surgical point of view, five spaces can be described in the orbit 94. 1.Subperiosteal space- This is a potential space between orbital bones and the periorbita It is limited anteriorly by the strong adhesions of periorbita to the orbital rim 95. Dermoid cyst, epidermoid cyst, mucocele, subperiosteal abscess, myeloma, osteomatous tumour, haematoma and fibrous dysplasia are commonly seen in this space. Plain X-rays are most useful in diagnosing the tumours of this space. 96. 2.Peripheral orbital space (anterior space)- This space is bounded peripherally by periorbita,internally by the four extraocular muscles with their intermuscular septa and anteriorly by the septum orbitale (including tarsal plates and tarsal ligaments). 97. Posteriorly, it merges with central space Tumours in this space produce eccentric proptosis and can usually be palpated. Common tumours found in this space are malignant lymphoma, capillary haemangioma of childhood, intrinsic neoplasms of the lacrimal gland and pseudotumours. 98. Tumours residing in this space are explored usually by anterior orbitotomy and some times by lateral orbitotomy 99. Contents of this space are peripheral orbital fat, superior oblique, inferior oblique and levator palpebrae superioris muscles; lacrimal, frontal, trochlear, anterior ethmoidal and posterior ethmoidal nerves; superior and inferior ophthalmic veins; lacrimal gland and half of the lacrimal sac. 100. 3.Central space- It is also called muscular cone or posterior or retrobulbar space This space is bounded anteriorly by Tenons capsule lining the back of the eye and peripherally by the extraocular rectus muscles and their intermuscular septa(in the anterior part) 101. In the posterior part this space becomes continuous with the peripheral orbital space. Contents of the central space include optic nerve and its meninges, superior and inferior divisions of oculomotor nerve, abducent nerve, nasociliary nerve, ciliary ganglion, ophthalmic artery, superior ophthalmic vein and the central orbital fat. 102. Many of the circumscribed orbital tumours such as cavernous haemangioma of adults, solitary neurofibroma, neurilemomas, nodular orbital meningiomas and optic nerve gliomas occur in this space and usually produce an axial proptosis. Such tumours are often removed through a lateral orbitotomy. 103. 4.SubTenons space- It is a potential space around the eyeball between the sclera and Tenon's capsule. Pus collecetd in this space is drained by incision of Tenon's capsule through the conjunctiva. 104. 5.Apical space- It is bounded peripherally by periorbita; anteriorly becoming continuous with the anterior (peripheral) and posterior (central) spaces, at the level of posterior limit of intermuscular membrane and ending posteriorly at the apex of the orbit 105. APERTURES AT THE BASE OF ORBIT The base of orbit is closed partially by the globe and extraocular muscles with their fascial expansions These expansions and two oblique muscles bound about five orifices between the orbital margin and globe Through these orifices fat may herniate from the orbit to come into contact with the septum orbitale 106. These apertures form a communication between the orbital cavity and deep portions of eyelids It is through them that blood and pus pass out of the orbit from the space between periorbita and peripheral fat Their further spread in the lids is stopped by septum orbitale. 107. These apertures are described as- 1.Superior aperture- This is a comma shaped orifice and lies between the roof of the orbit and the upper surface of the levator palpebrae superioris muscle. 108. Fat from the superomedial lobe may herniate through this aperture to form a retroseptal roll, which serves as an important landmark during levator resection surgery for ptosis. 109. 2.Superomedial aperture- This vertically oval aperture lies between the reflected tendon of the superior oblique muscle and the medial check ligament. The infratrochlear nerve, dorsal nasal artery and angular vein pass through this aperture. 110. Herniation of fat through this aperture is a common cause of lobulated prominence in old people 111. 3.Inferomedial aperture- This is vertically oval in shape It lies between the medial check ligament, origin of inferior oblique muscle and the lacrimal sac. 112. 4.Inferior aperture- This is triangular in shape It is bounded by the inferior oblique muscle, arcuate expansion of inferior oblique and floor of the orbit. 113. 5.Inferolateral aperture- This is a small oval aperture It is situated between the arcuate expansion of the inferior oblique muscle and the lateral check ligament 114. CONTENTS OF THE ORBIT Eyeball occupies about one fifth of the total orbital volume Muscles include superior rectus, inferior rectus, medial rectus, lateral rectus, superior oblique, inferior oblique, levator palpebrae superioris, and muller's muscles of the orbit 115. Nerves include optic nerve, oculomotor nerve, trochlear nerve, abducent nerve, branches of ophthalmic division of Vth nerve (lacrimal, frontal, nasociliary) and branches of maxillary division of Vth nerve (infraorbital, zygomatic). 116. Vessels include ophthalmic artery and its branches, Infraorbital vessels, orbital branch of middle meningeal artery and superior and inferior ophthalmic veins. Orbital fat, reticular tissue and orbital fascia. Lacrimal gland and lacrimal sac. 117. CONGENITAL & DEVELOPMENTAL ANOMALIES 118. Congenital anomalies can affect the orbit in two ways. First, there can be a primary defect in the structural architecture of the bony orbit. This type includes defects of the anterior cranial base and facial skeleton. Alternatively, defects in the development of the globe and soft tissues can induce secondary changes in the bony orbit. 119. Most congenital and developmental anomalies of the orbit can be classified into three categories: 1) Localized anomalies of the orbit 2) Craniosynostosis or deformities of premature cranial suture closure 3) Facial clefting syndromes Others are Non specific congenital orbital anomalies 120. LOCALIZED ORBITAL ANOMALIES Localized anomalies of the orbit and periorbital adnexa are the most common congenital defects These "localized" problems may affect other facial and intracranial structures. 121. MICROPHTHALMOS AND ANOPHTHALMOS- True anophthalmos is a rare condition that results from failure of development or complete regression of the optic vesicle. It is clinically indistinguishable from severe microphthalmos, which results from incomplete invagination of the optic vesicle or closure of the embryonic fissure. 122. The term clinical anophthalmos has been used to describe patients who have no clinical or radiographic evidence of an ocular remnant, although true anophthalmos can only be verified after careful histologic sectioning of the orbital tissues. 123. Anophthalmos and microphthalmos are usually unilateral and can be associated with a variety of craniofacial and systemic anomalies, including orbital hypoplasia, facial clefts, basal encephalocele, hemifacial microsomia, mandibulofacial dysostosis, cardiac anomalies, polydactyly, and mental retardation. 124. When unilateral, they also can be associated with anomalies of the other "normal" eye, including cataract, corneal opacities, microphthalmos, coloboma, epibulbar dermoids, and nystagmus. Unilateral microphthalmos and anophthalmos can be associated with secondary orbital hypoplasia 125. Anophthalmos and severe microphthalmos frequently are associated with small conjunctival fornices, phimotic eyelids, and generalized hypoplasia of the periocular soft tissues 126. When soft tissue contractures occur, the early use of conformers is essential to expand these tissues. This treatment should be instituted in the first month of life, with progressive enlargement of the conformer every 2 weeks to achieve maximum expansion of the conjunctival fornix. 127. Unfortunately, these soft tissue expanders have minimal effect on bony orbital growth. In recent years surgically placed expansile orbital implants have been advocated to stimulate bony orbital development. 128. DERMOID CYST- Dermoid cysts are developmental choristomas that are believed to arise from ectodermal rests pinched off by the fusion of bony sutures around the orbit. These cysts often originate from the frontozygomatic suture temporally But are also seen nasally, arising from the frontonasal and frontolacrimal sutures. 129. They rarely occur deep in the orbit. They commonly present during the first decade of life Presents as a well-circumscribed, firm, rubbery subcutaneous mass just below the temporal eyebrow. 130. Deeper dermoids can remain asymptomatic for many years, often presenting later in life as a slowly expanding orbital mass. Complete excision of these encapsulated lesions is the preferred treatment. Rupture of the cyst from trauma or during surgery can result in severe orbital inflammation 131. ORBITAL DYSTOPIA- It is defined as a vertical malignment of the globes. Congenital anomalies of orbital development are the most common cause of orbital dystopia. 132. These anomalies include craniosynostosis, hemifacial microsomia, and orbitofacial clefts. Acquired orbital dystopia can occur as a result of facial and orbital fractures or mass lesions that arise from the orbit, periorbital sinuses, and adjacent structures. 133. ANATOMIC VARIATION- A variety of localized aberrations occur in the bones and soft tissues of the orbit. These aberrations include accessory ossicles and sutures; redundant or misplaced notches, foramina, and canals; and variation in the orbital vascular supply. These conditions are sporadic and rarely have any clinical significance 134. CRANIOSYNOSTOSIS Craniosynostosis implies premature fusion of the bony sutures of the skull. These craniofacial anomalies usually display a sporadic inheritance pattern, although several well-recognized syndromes have distinct inheritance patterns, such as the autosomal dominant pattern of Crouzon's disease. 135. Although premature suture fusion was believed to be the primary pathologic process, evidence suggests that this early fusion may be a compensatory change caused by an abnormality in cranial bone development. 136. Scaphocephaly- It is an elongated, narrow cranium associated with premature fusion of the sagittal suture. Brachycephaly- It is a short, wide cranial vault associated with bilateral coronal synostosis. 137. Plagiocephaly- It results from premature closure of one coronal suture, leading to prominent orbital asymmetry A flattened, recessed forehead occurs on the affected side, and persistent growth of the contralateral side It results in frontal bossing, inferolateral orbital dystopia, and a prominent occiput. 138. Trigonocephaly- It is a triangular deformity of the anterior cranial fossa that results in medial displacement of the orbits (hypotelorism) 139. Acrocephaly- It results from multiple suture closure, including bicoronal synostosis. Typically, there is excessive skull height and a pointed head. 140. CROUZON'S DISEASE- This is a autosomal dominant disease This can have a variety of ocular findings, including exophthalmos, hypertelorism, strabismus, nystagmus, and optic atrophy. A variable pattern of suture closure is seen, including coronal, sagittal, and lambdoid sutures. 141. The deformities of the orbit and cranial vault are in part a result of the compensatory expansion of the cranium from increased intracranial pressure. Forward displacement of the greater wing of the sphenoid bone results in a shortening of the lateral orbital wall and a dramatic reduction in orbital volume. 142. To compound the problem, there is also inferior displacement of the orbital roof from anterior cranial fossa expansion and shortening of the orbital floor from maxillary hypoplasia. These defects account for a 6-cc reduction in orbital volume, or approximately 20% to 25% of the total volume of the orbit. 143. APERT'S SYNDROME- Ocular findings include brachycephaly, exophthalmos, hypertelorism, and maxillary hypoplasia. The distinguishing feature of Apert's syndrome is a symmetric syndactyly of the hands and feet. Ptosis, an antimongoloid slant to the intra- palpebral fissure, and oculomotor palsies can also be seen. 144. TREATMENT OF CRANIOSYNOSTOSIS- Early intervention is aimed at reducing the intracranial pressure to permit normal visual and mental development, and to achieve a satisfactory cosmetic result. 145. The techniques employed include a variety of frontal and facial bone advancements designed to expand the intracranial volume and improve the cosmesis of the facial skeleton 146. FACIAL CLEFTS Facial clefts range from small, isolated soft tissue defects to severe, disfiguring craniofacial deformities Tessier developed an anatomic classification for this diverse group of congenital anomalies Tessier classification numbers the clefts based on their location in relation to the orbit 147. Tessier cleft 0-14, a true median cleft, is associated with orbital hypertelorism and meningoencephalocele. 148. Clefts 1 and 2 are associated with telecanthus from involvement of the soft tissues of the medial canthus, but spare the lacrimal system and eyelids. Tessier clefts 3 and 4 involve the inferomedial orbit and lower eyelid medial to the punctum. 149. Tessier cleft 5 is associated with a defect in the inferolateral orbital rim and floor, a lateral lower eyelid cleft and, frequently, microphthalmia. Features of Tessier clefts 6, 7, and 8 are seen in Treacher-Collins syndrome, Goldenhar's syndrome, and hemifacial microsomia. 150. Tessier cleft 9 is characterized by defects in the superolateral orbital rim and the lateral one-third of the upper eyelid, and distortion of the lateral canthus. A central cleft of the eyebrow, upper eyelid, supraorbital rim, and orbital roof characterize Tessier cleft 10. 151. Tessier cleft 11 is characterized by defects in the medial aspect of the upper eyelid and brow, but no bony defect in the supraorbital rim. 152. Tessier cleft 12 is associated with telecanthus, hypertelorism, and a defect at the medial root of the eyebrow. Clefts 13 and 14 are characterized by hypertelorism with sparing of the orbital soft tissues. 153. NONSPECIFIC CONGENITAL ORBITAL ANOMALIES HYPERTELORISM- Orbital hypertelorism is defined as an abnormally wide distance between the orbits. It is not a syndrome, but a physical finding that is found in a variety of craniofacial anomalies. Hypertelorism implies an increased interpupillary distance. 154. Hypertelorism is associated with a variety of facial clefts, craniosynostosis, and meningoencephaloceles. The normal distance between the orbits is roughly 16 mm at birth and increases to 25 to 28 mm in adults. This distance is best measured by taking the shortest distance between the medial walls of the orbits on a transverse computed tomography scan. 155. A widening of the anterior ethmoid air cells is believed to be the main anatomic defect responsible for primary orbital hypertelorism. The posterior ethmoid air cells and the sphenoid bone are usually normal. As a result, the optic foramina are usually normal as well. 156. The cribiform plate is not widened, but can be depressed 10 mm below its usual level, making the extracranial approach to the correction of this defect hazardous. The angle between the central axis of each orbit is normally 25. In orbital hypertelorism, the axes of the orbits are more divergent, measuring up to 60 in severe cases. 157. There is an increase in soft tissue, bone, and cartilage between the medial canthi. Defects including nasolacrimal duct obstruction and absence of the puncta, have been described. Surgical correction of hypertelorism usually entails a combined intracranial and extracranial approach. 158. All four walls of each orbit are osteotomized to free them from the frontal, zygomatic, maxillary, nasal, and sphenoid bones. The excessive intervening tissues are removed, and the orbits are brought closer together in the midline. The resultant bone gaps are filled with bone grafts 159. MENINGOENCEPHALOCELE- Congenital defects in the bony sutures of the cranial skeleton can result in a herniation of brain and meninges into the orbit, known as meningoencephalocele This defect usually occurs medially between the sutures of the frontal, ethmoidal, lacrimal, or nasal bones. 160. A soft, pulsatile mass that bulges with coughing and valsalva appears in the upper medial canthal area during the first years of life. Rarely, a congenital dehiscence in the greater wing of the sphenoid bone results in a slowly progressive pulsatile, exophthalmos that presents later in life. 161. HEMIFACIAL MICROSOMIA- Complex disorder of unknown etiology It is characterized by facial asymmetry with ipsilateral abnormalities of the middle ear, mandibular ramus, and condyle. Dystopia can result from hypoplasia of the orbital bones. Associated systemic defects can involve the heart, kidneys, and limbs. 162. OCULOAURICULAR DYSPLASIA- Also known as Goldenhar's syndrome It is a unilateral disorder characterized by malformations of the eye, ear, and malar and vertebral structures It is a variant of hemifacial microsomia. 163. Soft tissue findings include epibulbar dermoids, orbital lipodermoids,eyelid colobomas, preauricular appendages, and aural fistulas. Marked facial asymmetry can occur due to unilateral hypoplasia of the zygoma, mandible, and chin. Abnormalities of the cervical vertebrae have been shown. 164. PROGRESSIVE HEMIFACIAL ATROPHY- Also known as Romberg's syndrome It is a rare disorder characterized by progressive atrophy of the skin, subcutaneous tissue, muscle, cartilage, and bone Usually involving only one side of the face. 165. This condition has been associated with a variety of ocular findings, including progressive enophthalmos, heterochromia, uveitis, restrictive strabismus, papillitis, retinal vasculitis and oculomotor nerve palsy. 166. MANDIBULOFACIAL DYSOSTOSIS- Also known as Treacher-Collins syndrome or Franceschetti syndrome It is a bilateral, autosomal dominant condition that results from abnormal development of structures derived from the first and second branchial arches 167. Hypoplasia of the maxilla, mandible, and zygoma are associated with a variety of soft tissue malformations. These malformations include underdevelopment of the midfacial musculature, lower eyelid colobomas, inferior displacement of the lateral canthi (antimongoloid slant), inferior punctal agenesis, and blepharoptosis. 168. Additional ocular anomalies may include high myopia, dermolipoma, lens subluxation, and secondary glaucoma. 169. PIERRE ROBIN SYNDROME- It is characterized by micrognathia, glossoptosis, cleft palate, and respiratory distress from airway obstruction at the level of the tongue. Associated ocular disorders include microphthalmia, congenital glaucoma, and high myopia, with associated retinal detachments. 170. FIBROUS DYSPLASIA- Fibrous dysplasia is a benign disorder characterized by an arrest of bone maturation that results in immature bone and osteoid in a cellular fibrous matrix. This congenital disease usually becomes clinically apparent in children and young adults. 171. It occurs in both monostotic and polyostotic forms. Polyostotic fibrous dysplasia sometimes is associated with cutaneous cafeau lait spots, endocrine abnormalities, and precocious puberty in girls,known as Albright's syndrome 172. Approximately one-third of all fibrous dysplasia patients show involvement of the facial bones or skull The maxillary, frontal, and sphenoid bones are most commonly involved. Maxillary bone involvement can cause nasolacrimal duct obstruction. 173. Involvement of the frontal and sphenoid bones can result in orbital asymmetry from contour deformities, vertical dystopia, and exophthalmos. Radiographically, fibrous dysplasia appears as an expansile bone lesion with a characteristic ground-glass appearance 174. Additional ocular complications include compressive optic neuropathy, oculomotor nerve palsy, and trigeminal neuralgia. Involvement of the sphenoid bone can result in narrowing of the optic canal, with secondary compressive optic neuropathy 175. Definitive treatment entails unroofing the optic canal by way of a transcranial approach, although high-dose steroids can be used as a temporizing measure. Fibrous dysplasia is not a true neoplasm; however, there is a small incidence of malignant degeneration, usually into osteogenic sarcoma 176. Treatment options range from careful observation to aggressive debulking of the diseased bone, with subsequent reconstruction Recent advances in craniofacial surgery, including cranial bone grafting with mini- and microplate fixation, have made the latter approach more appealing. 177. ANENCEPHALY- Partial or total absence of the brain It is a severe congenital birth defect incompatible with life. This dramatic deformity results from failure of forebrain development. 178. The vault of the skull is absent, and the forebrain consists of a degenerated mass of glial tissue. The orbits are shallow and tilted upward. The eyes are fairly well developed, but the optic nerves, when present, taper down to a loose mass of glial tissue at the optic canal. 179. CYCLOPIA/SYNOPHTHALMOS- True cyclopia (cyclopia sensu stricto) is a rare congenital anomaly characterized by a single eye situated in a single median orbit. Synophthalmos (cyclopia sensu lato) is much more common than true cyclopia, occurs when paired ocular structures are found in a single median orbit 180. These disorders result from failure of lateralization of the midline facial structures 181. THANK YOU