Definition: Benign eyelid lesions can arise from epithelial or dermal adnexal elements. These include epithelium, hair follicles, apocrine and eccrine glands, blood vessels, and nerves. Some may appear aggressive and must be differentiated from malignancies. Key Features Three to six…
Definition Ectropion is an outward rotation of the eyelid margin from the eye. Key Features Ectropion may result from progressive age-related eyelid laxity, vertical skin shortening, orbicularis muscle weakness from facial nerve palsy, or mechanical force on the eyelid from…
Definition Entropion: a commonly encountered inward rotation of the tarsus and eyelid margin ( Fig. 12.5.1 ). Key Features Symptoms and signs include ocular foreign body sensation, secondary blepharospasm, ocular discharge, tearing, superficial keratopathy, and corneal scarring. The natural course…
Definition Ptosis is defined as the upper eyelid resting in a droopy, abnormally low position while the eye is in primary gaze. Key Features Blepharoptosis (ptosis) is caused by a weakness in one or both of the eyelid retractors, the…
Definitions Computed tomography: An imaging technique where contrast differences are based on tissue density based on the passage of X-rays through tissues. Magnetic resonance imaging: An imaging technique where density differences are based on tissue proton density and their resonance…
Definition The orbit is the anatomical space bounded by seven orbital bones and enclosed within the multilamellar periorbita. It is separated above from the intracranial compartment and medially and inferiorly from the paranasal sinuses. The orbit contains the eye and…
Definition The eyelids are mobile, flexible, multilamellar structures that cover the globe anteriorly. They protect the ocular surface, spread the precorneal tear film, and help propel tears into the lacrimal drainage system. Anatomically, the eyelids are composed of an anterior…
Definition Strabismus surgery is physical manipulation of the extraocular muscles with the goal of therapeutic benefit. Key Feature The ideal strabismus surgery needs to merge fusional potential garnered through preoperative testing with education about realistic patient expectations and excellent surgical…
Definitions Orthoptics: a wide range of techniques used to expand fusional vergence amplitudes and permit improved single binocular vision. Convergence insufficiency: a deficiency in convergence of the eyes to focus on a near target, causing symptoms such as difficulty reading.…
Definition Amblyopia is diminished vision that results from discordant visual experience during the first years of life when the visual pathways are within the early stages of maturation. Key Features Reduced visual acuity accompanied by an amblyogenic factor, most commonly…