Congenital ectropion is not a single disease and therefore it is difficult to define a single genetic error or a solitary etiopathogenic event as a causative factor; hence, respective etiologies or genetic mechanisms will be discussed briefly.

The cause of congenital upper eyelid eversion with conjunctival chemosis is unknown, but it is theorized that birth trauma or pressure exerted on the baby during delivery may induce venous stasis, leading to conjunctival chemosis and subsequent prolapse, which causes eyelid eversion. This mechanical eyelid eversion causes secondary orbicularis spasm, which may act as a sphincter at the base of the everted eyelid causing a domino effect of conjunctival strangulation and further edema.³,⁴,⁵ In our opinion, this “birth trauma” theory needs to be revised. Several other authors have also reported similar cases in children delivered through uneventful vaginal delivery,⁵,⁶ and even more interestingly, this theory is further challenged by a single case report from Russian literature, wherein neonatal lid eversion occurred in a child born by cesarean section.⁷

Lamellar ichthyosis is a hereditary condition commonly transmitted in an autosomal recessive fashion, whereby several different genetic mutations particularly in the TGM1 gene (chromosome 14q11), or in the long arm of chromosome 2 (2q33), alter the normal development and function of keratinocytes, causing a defect in skin desquamation.⁸,⁹,¹⁰,¹¹,¹²,¹³ Although there are other types of congenital ichthyosis, their clinical picture varies widely, and eyelid changes are only found in classic lamellar ichthyosis¹⁴ and its phenotypic or genotypic variants, congenital (nonbullous) ichthyosiform erythroderma (CIE), and harlequin ichthyosis, which all fall under the umbrella term “autosomal recessive congenital ichthyosis.”¹⁵

Down syndrome, or trisomy 21, is the most common nonheritable chromosomal disorder associated with mental and growth retardation, affecting approximately 1 in 600 live births. Several ocular and adnexal sequelae are reported with Down syndrome.¹⁶

Because congenital ectropion is a rare entity, and because the literature is rather confusing, the incidence is largely unknown. The term “congenital ectropion” itself is a collective one used to describe a variety of heterogenous conditions under a universal banner; therefore, several classifications have been put forward to better understand the disease and to reduce confusion. Based on a clinicopathological study in a family pedigree, Picò in 1959 first attempted to classify the disease into four types, followed by França in 1997 who refined the classification.¹⁷,¹⁸ According to Picó, group 1 encompasses patients with true congenital ectropion due to tarsal dysgenesis, group 2 occurs due to birth trauma, group 3 occurs as a result of anterior lamellar shortening, and group 4 includes cases secondary to abnormalities in the size or position of the globe or orbit. Because the presence of group 1 is uncertain, and because cases that fall into group 4 do not represent true ectropion and may be reversible with treatment of the original condition, we believe that both
classifications may be unsatisfactory and, in our experience, congenital ectropion falls into three simple categories:

Although we do not include it in our simple classification, group 1 in Picó’s original description deserves special mention. It was termed “true congenital ectropion” because it allegedly occurs due to congenital absence or dysgenesis of the tarsus and is an extremely rare entity.¹⁷ Picó described eight patients where no tarsus was felt on palpation of the eyelid, either during surgery or on histopathological examination.¹⁷ Interestingly, he extensively studied the literature before his 1959 paper and failed to find a single case report where the tarsus was truly congenitally absent. We conducted an extensive literature search from 1959 till the present, and to the best of our knowledge at least at the time of writing, tarsal dysgenesis causing true congenital ectropion was never described again after his initial report. Whether this entity truly exists or not is unknown, but its existence is disputed by other authors as well.¹

Idiopathic congenital bilateral upper eyelid eversion (Figures 17.1 and 17.2) is a benign self-limiting and extremely rare condition except in African black neonates where the condition is not uncommon, as evidenced by the large number of cases reported in Africa.⁵,⁶ It even poses a sociocultural problem there, wherein parents are forced to apply unsafe traditional medicinal practices.⁵,⁶,¹⁸ These patients who are usually systemically free typically present immediately after birth with bilateral fleshy masses, completely or less commonly partially covering the eyeballs. The conjunctiva protrudes well outside the confines of the eyelid margin, with complete eversion of the upper and occasionally lower eyelids.⁵,⁶,¹⁹,²⁰,²¹,²² Because the ocular surface is technically protected by the protruding conjunctiva, corneal problems are not observed. The upper eyelid may be more predisposed to congenital eversion because of its wider tarsal plate, which may be difficult to reinvert spontaneously once everted.²³ The condition is usually self-limited within 2 to 3 weeks.⁵,⁶