The Eyelids DR NAILA ALI ASSISTANT PROFESSOR OPHTHALMOLOGY

The Eyelids DR. NAILA ALI ASSISTANT PROFESSOR OPHTHALMOLOGY

The eyelids are movable folds which act as a shutter protecting eye from injury or excessive light. § Both the upper and lower eyelids meet at medial and lateral canthi with the opening the papebral fissure between them.

SURFACE ANATOMY § Superior Palpebral Sulcus § Lateral Canthus § Medial Canthus § Palpebral Fissure

ON THE MEDIAL SIDE § § § Lacus lacrimalis Caruncula lacrimalis Plica semilunaris

The medial 1/6 th is distinct and it contains § § § papilla lacrimalis punctum lacrimalis canaliculus lacrimalis.

THE STRUCTURE The margin of each eyelid is 2 mm thick and 30 mm long It contains eyelashes and just posterior to it are the meibomian glands orifices. The tissues of the lids from anterior (cutancous) to posterior conjunctival aspects as follows: - § § § § skin subcutaneous areolar tissue layer of striated muscle (orbicularis oculi) sub muscular areolar tissue layer of non striated muscle the fibrous layer—including tarsal plate conjunctiva

THE SKIN § It is thinnest and marked by sulci. § The superior sulci is due to aponeurosis of levalor palpebrae superior inserted into the skin. § The less obvious lower sulci is due to the skin being tethered to the underlying periosteum. § Histologically it consist of epidermis, sebaceous and sweat gland melanocytes.

EYE LASHES § § § 100 in upper lid 50 in lower lid Originate from anterior lamella in two or three irregular rows. The upper lid lashes are directed upward, and outwards The lower lid lashed are directed downward and outwards

THE SUBCUTANEOUS AREOLAR TISSUE § It is a loose connective tissue containing no fat. § It is absent at medial and lateral angles, ciliary margin and at sulci.

THE ORIBICULARIS OCULI Part Position § Orbital Surrounds the orbital rim § Preseptal In front of the orbital Septum § Pretarsal in front of the tarsal Plate Function Forced lid closure pull lacrimal fascia laterally and create a relative vacuum in lacrimal sac. Close lid and pull lacrimal puncta medially

THE FIBROUS LAYER---ORBITAL SEPTUM AND TARSAL PLATE § Attached to the orbital margin. § Lies post to the medial palpebral ligament and lateral palpebral raphe medially and laterally. § With in the lids it is thickened to form tarsal plates—embedded in it are tarsal glands.

THE LIGAMENTS § The medial palpebral ligament attaches the medial end of tarsi to lacrimal crest and frontal process of maxilla. § The lateral palpebral ligament attach the lateral end of tarsi to margin tubercle on marginal tubercle of zygomatic bone.

LEVATOR PALPEBRAE SUPERIOR § Originate from lesser wing of sphenoid bone and is inserted an aponeurosis on the ant surface of superior tarsal plate, skin, lat palpebral ligament, medial palpebral ligament § From its inferior surface arises the superior tarsal muscle.

CONJUNCTIVA § Thin mucous membrane lined by non keratinized stratified squamous epithelium. § It has a richly vascularized Substantia propria § At the margin of the eyelids it is continuous with the skin.

ARTERIAL SUPPLY § The lateral palpebral Artery---lacrimal artery. § medial palpebral artery ---Ophthalmic Artery. § Marginal and Peripheral arcades.

VENOUS DRANAGE § Medially – Ophthalmic and angular vein § Laterally-superficial temporal vein

§ § NERVE SUPPLY Upper eyelid § § Supra orbital nerve Supra trochlear nerve Infra trochlear nerve Lacrimal nerve Lower eyelid § § Infra trochlear nerve Infra orbital nerve

LYMPHATIC DRAINAGE

SECRETION OF THE EYELIDS Glands Tear Film Layer § Meibomian gland Oily layer § § § Oily layer Aqueous layer Glands of Zei’s Glands of Wolfring Glands of Krause Location of glands Tarsal plate Eyelashes Tarsal plate Fornix

Blinking There are two main types of blinking § Reflex blinking § Spontaneous Blinking

Reflex Blinking Tactile § Corneal Touch § Cortical Connection § Dimunation of sensitivity in contact lens wearer Dazzle § Bright light § Optic nerve--- Superior colliculus § Associated fiber to facial nuclei Menace § Sudden presence of near object § Optic nerve--- Cortical Connection § Predominantly cortical in nature

Spontaneous Blinking – Occurs at regular basis without an apparent external stimuli. – Mechanics facilitates the drainage of tear film. – Present in blind as no retinal stimuli are required.

Blephrospasm § Simultaneous forcible contraction of orbiculars oculi. § Forcible closure of the lids. § Its role in surgical procedures. § Anterior segment injury.

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