2020–2021 BCSC Basic and Clinical Science Course™
6 Pediatric Ophthalmology and Strabismus
Part II: Pediatric Ophthalmology
Chapter 17: Eyelid Disorders
This chapter includes a related video, which can be accessed by scanning the QR code provided in the text or going to www.aao.org/bcscvideo_section06.
Eyelid anatomy is described in BCSC Section 2, Fundamentals and Principles of Ophthalmology, and Section 7, Oculofacial Plastic and Orbital Surgery. Section 7 also discusses many of the eyelid disorders covered in this chapter.
Congenital Eyelid Disorders
Eyelid malformations can be isolated or associated with orbital malformations; they can also represent features of a syndrome. Because of these possibilities, systematic evaluation of the eyelids and ocular adnexa may be an important part of the clinical evaluation of a dysmorphic infant.
Morphologic measurements of the eyelids and orbit can be compared with normal reference measurements and may have clinical significance (Fig 17-1; see also Chapter 18). The Farkas canthal index, defined as the ratio of inner canthal distance to outer canthal distance, can also be used. A canthal index lower than 38 signifies ocular hypotelorism (smaller-than-average distance between the eyes), and a canthal index greater than 42 indicates ocular hypertelorism (greater-than-average distance between the eyes). Ethnic variations may occur.
Dystopia canthorum is lateral displacement of both the inner canthi and the lacrimal puncta such that an imaginary vertical line connecting the upper and lower puncta crosses the cornea (Fig 17-2). The displacement is a characteristic feature of Waardenburg syndrome type 1.
Excerpted from BCSC 2020-2021 series: Section 10 - Glaucoma. For more information and to purchase the entire series, please visit https://www.aao.org/bcsc.