21 - Disorders of the Anterior Segment Flashcards

Question

# (Aniridia) Définir l'Aniridie.

Answer 1

* Classic aniridia is a **panocular bilateral disorder**. * The term is a misnomer, however, because at least a rudimentary iris is always present.

Answer 2

The degree of iris formation ranges from almost total absence to only mild hypoplasia, overlapping with ARS.

Answer 3

The typical presentation is an infant * With nystagmus * Who appears to have absent irides or dilated, unresponsive pupils.

Answer 4

* Examination findings commonly include **small anterior polar lens opacities**, at times with attached strands of **persistent pupillary membranes**. * **Foveal hypoplasia** is usually present, with visual acuity often less than 20/100. * **Glaucoma**, typically juvenile, and optic nerve hypoplasia are common. * **Corneal opacification** often develops later in childhood and may lead to progressive deterioration of visual acuity.

Answer 5

* The corneal abnormality is due to a **stem cell deficiency** * Therefore, **keratolimbal allograft stem cell transplantation** may be a more effective treatment than corneal transplantation.

Answer 6

* Heterozygous **PAX6** gene mutations (**11p13**) cause classic aniridia, particularly **nonsense mutations (haploinsufficiency)**. * Missense mutations are more likely associated with variable expressivity and partial phenotypes. * Most (approximately two- thirds) aniridic children have the **familial form**. Donc : * Mutation : PAX6 * Chromosome : 11 * Hx familiale : Forme familiale 2/3 des enfants atteints

Answer 7

Approximately one- third of aniridia cases result from new deletions that, if large enough, can also affect the contiguous **WT1 gene** (a contiguous gene syndrome); such patients are therefore at risk for **Wilms tumor (nephroblastoma)** before 5 years of age.

Answer 8

This phenotype is part of the **WAGR syndrome** * **W**ilms tumor * **A**niridia * **G**enitourinary malformations * Mental **R**etardation

Answer 9

* All children with **sporadic aniridia** should undergo chromosomal deletion analysis of 11p13 to exclude increased Wilms tumor risk. * **Familial aniridia does not carry a significant risk**, although there have been **rare reports** of Wilms tumor associated with familial aniridia.

Answer 10

Ectropion of the **posterior pigment epithelium onto the anterior surface of the iris** is sometimes termed ectropion uveae, but this is a misnomer because posterior iris epithelium is derived from neural ectoderm and is not considered part of the uvea.

Answer 11

Congenital iris ectropion can occur * As an **acquired tractional abnormality**, often associated with rubeosis iridis, or * As a **congenital nonprogressive abnormality** * Which can be associated with later glaucoma.

Answer 12

It may occur in patients with * Neurofibromatosis * Facial hemihypertrophy * Prader- Willi syndrome

Answer 13

Congenital iris ectropion syndrome is a **constellation of unilateral** * Congenital iris ectropion * A glassy- smooth cryptless iris surface * A high iris insertion * Dysgenesis of the drainage angle * Glaucoma risk * Often with ptosis.

Answer 14

Dyscoria is an **abnormal pupil shape**, typically resulting from congenital malformation such as ARS.

Answer 15

Microcoria

Answer 16

* Congenital miosis (microcoria) may represent an **absence or malformation of the dilator pupillae muscle**. * It can also occur secondary to **contracture of fibrous material on the pupil margin** owing to remnants of the tunica vasculosa lentis or neural crest cell anomalies. À r/o : rubéole congénitale, ataxie héréditaire, syndrome de Lowe

Answer 17

The pupil : * Rarely exceeds 2 mm in diameter * Is often eccentric * Reacts poorly to mydriatic drops. Severe cases require surgical pupilloplasty.

Answer 18

Ectopia lentis et pupillae refers to **eccentric microcoria with lens subluxation**, often from biallelic **ADAMTSL4** mutations

Answer 19

Ectopia lentis et pupillae refers to eccentric microcoria with lens subluxation, often from biallelic **ADAMTSL4** mutations

Answer 20

Iridoplegia

Answer 21

Vrai. Many cases of congenital mydriasis (iridoplegia) fall within the aniridia spectrum, especially if the central iris structures from the collarette to the pupillary sphincter are absent.

Answer 22

**Congenital cardiovascular** **defects** may be associated with congenital mydriasis in patients with heterozygous ACTA2 mutation, which sometimes causes an alternate phenotype of prominent iris flocculi rather than iridoplegia.

Answer 23

Congenital cardiovascular defects may be associated with congenital mydriasis in patients with heterozygous **ACTA2** mutation, which sometimes causes an alternate phenotype of prominent iris flocculi rather than iridoplegia.

Answer 24

Other causes include * Iris sphincter trauma * Pharmacologic mydriasis * Acquired neurologic disease that affects parasympathetic innervation

Answer 25

* Normally, the pupil is located approximately **0.5 mm inferonasally from the center of the iris**. * **Minor deviations of up to 1.0 mm** are usually cosmetically insignificant and are **not considered abnormal**; * **Displacement greater than 1.0 mm is considered corectopia**

Answer 26

**Sector** iris hypoplasia or other **colobomatous lesions** can lead to corectopia.

Answer 27

Vrai. Vision can be good.

Answer 28

Réponse : 1 et 3 sont faux. * Ectopia lentis et pupillae is corectopia **associated** with lens subluxation. * It is often due to biallelic **ADAMTS4** mutations. * The pupils and lenses are displaced in **opposite** directions. * The pupils **may be very small and misshapen**; they often **dilate poorly** (misshapen = diforme)

Answer 29

Progressive corectopia can be associated with * ARS * In adults : iridocorneal endothelial (ICE) syndrome

Answer 30

Vrai. Isolated noncolobomatous, autosomal dominant corectopia has been reported.

Answer 31

* True polycoria (in which each pupil has a sphincter mechanism) is very rare. * Most accessory iris openings are pseudopolycoria.

Answer 32

These iris holes : * May be **congenital** * May **develop** in response to **progressive corectopia and iris hypoplasia in ARS** or, in adults, in **ICE syndrome**. Pseudopolycoria can also result from * Trauma * Surgery * Persistent pupillary membranes

Answer 33

Primaire * Bilatérale * Congénitale * Augmentation D horizontal cornée * CA profonde * Transillumination iris * X-linked recessive mutation (CHRDL1) * Versus Buphtalmos : Enlarged Eyeball (au complet) Secondaire * Typiquement 2nd augmentation PIO

Answer 34

Microcornea is characterized by a horizontal corneal diameter of * **9 mm or less at birth** * **Less than 10 mm after 2 years of age** It is often a component of * Ocular malformations such as Microphthalmia et Persistent fetal vasculature * Syndromes such as Oculodentodigital syndrome, Nance- Horan syndrome et Lenz syndrome

Answer 35

Keratoglobus is characterized by * A **steep** corneal **curvature** (forte courbure k) * A **peripheral** corneal **thinning** * A very **deep anterior chamber** The phenotype can be due to **brittle cornea syndrome**, which is the result of biallelic mutations in ZNF469 or PRDM5. Spontaneous breaks in Descemet membrane may produce acute corneal edema. Because the cornea can be ruptured by minor blunt trauma, **wearing protective spectacles** full time is appropriate.

Answer 36

**Keratoconus is characterized by central or paracentral corneal bulging (renflement) and progressive thinning.** It may present and progress during adolescence and is often familial. Keratoconus is more common in * Down syndrome * Atopic diseases * Leber congenital amaurosis * Chronic eye rubbing. Iron lines (Fleischer rings), stress lines (Vogt striae), and apical scarring are often noted. Tears in Descemet membrane can occur and cause acute corneal edema (hydrops).

Answer 37

Keratoconus is characterized by central or paracentral corneal bulging (renflement) and progressive thinning. **It may present and progress during adolescence and is often familial.** Keratoconus is more common in * Down syndrome * Atopic diseases * Leber congenital amaurosis * Chronic eye rubbing. Iron lines (Fleischer rings), stress lines (Vogt striae), and apical scarring are often noted. Tears in Descemet membrane can occur and cause acute corneal edema (hydrops).

Answer 38

Keratoconus is characterized by central or paracentral corneal bulging (renflement) and progressive thinning. It may present and progress during adolescence and is often familial. Keratoconus is more common in * **Down syndrome** * **Atopic diseases** * **Leber congenital amaurosis** * **Chronic eye rubbing** Iron lines (Fleischer rings), stress lines (Vogt striae), and apical scarring are often noted. Tears in Descemet membrane can occur and cause acute corneal edema (hydrops).

Answer 39

Keratoconus is characterized by central or paracentral corneal bulging (renflement) and progressive thinning. It may present and progress during adolescence and is often familial. Keratoconus is more common in * Down syndrome * Atopic diseases * Leber congenital amaurosis * Chronic eye rubbing. **Iron lines (Fleischer rings), stress lines (Vogt striae), and apical scarring** are often noted. Tears in Descemet membrane can occur and cause acute corneal edema (hydrops).

Answer 40

Posterior embryotoxon (**prominent Schwalbe line**) represents a **thickening and anterior displacement of the Schwalbe line**, causing the anomaly to be seen as an irregular **white line** just concentric with and **anterior to the limbus** It is a common isolated finding (occurring in 15% of healthy patients) but is often seen in * Axenfeld- Rieger syndrome * Arteriohepatic dysplasia (Alagille syndrome) * Velocardiofacial syndrome (22q11 deletion syndrome).

Answer 41

Posterior embryotoxon (prominent Schwalbe line) represents a thickening and anterior displacement of the Schwalbe line, causing the anomaly to be seen as an irregular white line just concentric with and anterior to the limbus It is a common isolated finding (occurring in 15% of healthy patients) but is often seen in * **Axenfeld- Rieger syndrome** * **Arteriohepatic dysplasia** (Alagille syndrome) * **Velocardiofacial syndrome** (22q11 deletion syndrome).

Answer 42

Posterior embryotoxon (prominent Schwalbe line) represents a thickening and anterior displacement of the Schwalbe line, causing the anomaly to be seen as an irregular white line just concentric with and anterior to the limbus It is a common isolated finding (**occurring in 15% of healthy patients**) but is often seen in * Axenfeld- Rieger syndrome * Arteriohepatic dysplasia (Alagille syndrome) * Velocardiofacial syndrome (22q11 deletion syndrome).

Answer 43

Cornea plana is a pathognomonic phenotype of flat cornea * Indistinct limbus * Shallow anterior chamber * Hyperopia * Associated accommodative esotropia It is specific for biallelic KERA mutations. Refractive correction and monitoring for glaucoma, which may develop later in life, are the mainstays of treatment.

Answer 44

An epibulbar (limbal) dermoid is a **choristoma composed of fibrofatty tissue covered by keratinized epithelium**; it **may contain hair follicles, sebaceous glands, or sweat glands**.

Answer 45

The dermoid often **straddles the limbus** (**typically inferotemporally**) or, less frequently, resides more centrally in the cornea.

Answer 46

It is typically **less than 10 mm in diameter**, with minimal postnatal growth.

Answer 47

Epibulbar dermoids may be seen in **Goldenhar syndrome** Patients with Goldenhar syndrome may have one or more of a variety of anomalies, including * Ear deformities or periauricular tags * Maxillary or mandibular hypoplasia * Vertebral deformities * Eyelid colobomas * Duane retraction syndrome

Answer 48

Vrai. Epibulbar dermoids can produce astigmatism with secondary anisometropic amblyopia. Surgical excision may be indicated if they cause ocular irritation or amblyopia, but the procedure may result in scarring and astigmatism, which can also lead to amblyopia.

Answer 49

A dermolipoma is an **epibulbar choristoma** composed of **adipose and dense connective tissue**. Often, dermal tissue, including hairs, has replaced a portion of the overlying conjunctiva. Dermolipomas can be extensive, involving orbital tissue, the lacrimal gland, extraocular muscle, or a combination of these. Like limbal dermoids, dermolipomas can be associated with Goldenhar syndrome. Dermolipomas rarely require excision.

Answer 50

A dermolipoma is an epibulbar choristoma composed of adipose and dense connective tissue. Often, dermal tissue, including hairs, has replaced a portion of the overlying conjunctiva. Dermolipomas can be extensive, involving orbital tissue, the lacrimal gland, extraocular muscle, or a combination of these. Like limbal dermoids, dermolipomas can be associated with **Goldenhar syndrome**. Dermolipomas rarely require excision.

Answer 51

Faux. Dermolipomas **can be extensive**, involving orbital tissue, the lacrimal gland, extraocular muscle, or a combination of these.

Answer 52

STUMPED : * **Sclerocornea** * **Tears in Descemet membrane** (usually owing to forceps trauma or congenital glaucoma) * **Ulcers** (infection) * **Metabolic disorders** (eg, mucopolysaccharidosis) * **Peters anomaly** * **Edema** (eg, congenital hereditary endothelial dystrophy [CHED], posterior polymorphous corneal dystrophy [PPCD], congenital hereditary stromal dystrophy [CHSD], glaucoma) * **Dermoid**

Answer 53

Ectropion of the posterior pigment epithelium onto the anterior surface of the iris is sometimes termed ectropion uveae, but this is a misnomer because posterior iris epithelium is derived from neural ectoderm and is not considered part of the uvea.

Answer 54

Congenital iris ectropion can occur as an acquired tractional abnormality, often associated with rubeosis iridis, or as a congenital nonprogressive abnormality, which can be associated with later glaucoma. It may occur in patients with * Neurofibromatosis * Facial hemihypertrophy * Prader- Willi syndrome

Answer 55

Congenital iris ectropion syndrome is a constellation of unilateral congenital * Iris ectropion * A glassy- smooth cryptless iris surface * A high iris insertion * Dysgenesis of the drainage angle * Glaucoma risk * Often with ptosis.

Answer 56

Dyscoria is an abnormal pupil shape, typically resulting from congenital malformation such as ARS

Answer 57

* Congenital miosis (microcoria) may represent an **absence or malformation of the dilator pupillae muscle**. * It can also occur **secondary to contracture of fibrous material on the pupil margin owing to remnants of the tunica vasculosa lentis or neural crest cell anomalies**. * The pupil rarely exceeds 2 mm in diameter, is often eccentric, and reacts poorly to mydriatic drops. * Severe cases require surgical pupilloplasty. * « Ectopia lentis et pupillae » refers to eccentric microcoria with lens subluxation, often from biallelic ADAMTSL4 mutations.

Answer 58

Many cases of congenital mydriasis (iridoplegia) fall **within the aniridia spectrum**, especially if the central iris structures from the collarette to the pupillary sphincter are absent. **Congenital cardiovascular defects** may be associated with congenital mydriasis in patients with heterozygous ACTA2 mutation, which sometimes causes an alternate phenotype of prominent iris flocculi rather than iridoplegia. Other causes include * Iris sphincter trauma * Pharmacologic mydriasis * Acquired neurologic disease that affects parasympathetic innervation

Answer 59

Normally, the pupil is located **approximately 0.5 mm inferonasally** from the center of the iris.

Answer 60

Minor deviations of up to 1.0 mm are usually cosmetically insignificant and are not considered abnormal; displacement greater than this is considered corectopia. **Displacement > 1 mm**

Answer 61

* Ectopia lentis et pupillae is corectopia associated with lens subluxation. * It is often due to biallelic ADAMTS4 mutations. * The pupils and lenses are displaced in opposite directions. * The pupils may be very small and misshapen; they often dilate poorly

Answer 62

* True polycoria (in which each pupil has a sphincter mechanism) is very rare. * Most accessory iris openings are pseudopolycoria. * These iris holes may be congenital or may develop in response to progressive corectopia and iris hypoplasia in ARSor, in adults, in ICE syndrome. * Pseudopolycoria can also result from trauma, surgery, or persistent pupillary membranes.

Answer 63

* True polycoria (in which each pupil has a sphincter mechanism) is very rare. * Most accessory iris openings are pseudopolycoria. * These iris holes may be congenital or may develop in response to progressive corectopia and iris hypoplasia in **ARS** or, in adults, in **ICE syndrome**. * Pseudopolycoria can also result from **trauma, surgery, or persistent pupillary membranes**. Donc : Ddx Pseudopolycorie * Trauma * Axenfeld Reiger * ICE syndrome * Chx * PPM

Answer 64

* The etiology of Thygeson superficial punctate keratitis is **unclear**, but it is thought to be **immune- mediated**. * It can occur in children and presents with tearing, photophobia, and reduced vision. * The condition is bilateral but often asymmetric. * Characteristic features include slightly elevated gray corneal epithelial lesions with negative staining. * It is treated with mild corticosteroids (eg, fluorometholone 0.1%) or topical cyclosporine 0.05%.

Answer 65

* The etiology of Thygeson superficial punctate keratitis is unclear, but it is thought to be immune- mediated. * It can occur in children and presents with **tearing, photophobia, and reduced vision**. * The condition is bilateral but often asymmetric. * Characteristic features include slightly elevated gray corneal epithelial lesions with negative staining. * It is treated with mild corticosteroids (eg, fluorometholone 0.1%) or topical cyclosporine 0.05%.

Answer 66

* The etiology of Thygeson superficial punctate keratitis is unclear, but it is thought to be immune- mediated. * It can occur in children and presents with tearing, photophobia, and reduced vision. * The condition is bilateral but often asymmetric. * Characteristic features include **slightly elevated gray corneal epithelial lesions with negative staining**. * It is treated with mild corticosteroids (eg, fluorometholone 0.1%) or topical cyclosporine 0.05%.

Answer 67

* The etiology of Thygeson superficial punctate keratitis is unclear, but it is thought to be immune- mediated. * It can occur in children and presents with tearing, photophobia, and reduced vision. * The condition is bilateral but often asymmetric. * Characteristic features include slightly elevated gray corneal epithelial lesions with negative staining. * It is treated with **mild corticosteroids** (eg, fluorometholone 0.1%) or **topical cyclosporine 0.05%.**

Answer 68

Laboratory tests for **serum copper and ceruloplasmin** are better than an eye examination for early diagnosis because the ring can develop late.

Answer 69

* Fabry disease is an X- linked lysosomal storage disease with variable systemic manifestations. * It is due to alpha - galactosidase deficiency (hemizygous GLA mutations). * Vortex keratopathy (verticillata) can be seen in affected males and in female carriers.

Answer 70

* Schnyder corneal dystrophy is a **predominantly local disorder of corneal lipid metabolism** arising from biallelic UBIAD1 mutations. * Although crystalline keratopathy is characteristic, stromal haze without crystals is a common presentation.

Answer 71

Juvenile xanthogranuloma is a **nonneoplastic histiocytic proliferation** that develops in infants younger than 2 years. (prolifération histiocytaire non néoplasique) Rare benign histiocytic proliferation that develops in infants and young children. It is characterized by the presence of **Touton giant cells**.

Answer 72

* Skin involvement— consisting of **one or more small, round, orange or tan papules**—is typically but not always present. * Iris lesions are relatively **rare** and virtually always **unilateral**. * The **fleshy, yellow- brown masses** may be **small and localized** or may **diffusely infiltrate the entire iris, resulting in heterochromia**. * Those at greatest risk for ocular involvement are children with multiple skin lesions.

Answer 73

* **Spontaneous bleeding with hyphema** is a characteristic clinical presentation. * **Secondary glaucoma** may cause acute pain, photophobia, and vision loss.

Answer 74

* Juvenile xanthogranuloma is a self- limited condition that usually **regresses spontaneously by age 5 years**, but to avoid complications, treatment is indicated for ocular involvement. * Topical corticosteroids and pharmacologic agents to lower intraocular pressure, given as necessary, are generally sufficient to control the problem. * Surgical excision or radiation should be considered if intractable (intraitable) glaucoma is present.

Answer 75

* Juvenile xanthogranuloma is a self- limited condition that usually regresses spontaneously by age 5 years, but to avoid complications, treatment is indicated for ocular involvement. * **Topical corticosteroids** and **pharmacologic agents to lower intraocular pressure**, given as necessary, are generally sufficient to control the problem. * **Surgical excision or radiation** should be considered if intractable (intraitable) glaucoma is present.

Answer 76

* Iris mammillations may be unilateral or bilateral. * They appear as numerous tiny, diffuse, pigmented nodules on the surface of the iris. * They are more common in darkly pigmented eyes and are usually the same color as the iris. * They must be differentiated from Lisch nodules; mammillations are usually dark brown, smooth, uniformly distributed, and equal in size or slightly larger near the pupil. * The incidence of iris mammillations is higher among patients with neurofibromatosis type 1.

Answer 77

**Focal areas of iris stromal hyperplasia surrounded by relative hypoplasia** occur in up to 90% of patients with **Down syndrome**; in such patients, these areas are known as Brushfield spots. They are hypopigmented. Similar lesions, known as **Wolfflin nodules**, occur in **up to 24% of healthy individuals**. Neither condition is visually significant.

Answer 78

* A medulloepithelioma (diktyoma) originates from the **nonpigmented epithelium of the ciliary body** and most **often presents as an iris mass during the first decade of life**. * Secondary glaucoma, hyphema, and ectopia lentis et pupillae or sectoral cataract (Fig 21-21) are less frequent initial manifestations. * This **rare lesion** shows a spectrum of clinical and pathologic characteristics, ranging from benign to malignant. * Although distant metastasis is rare, **local invasion can lead to death**. * **Teratoid elements** are often present. * **Enucleation** is usually required and is curative in most cases.

21 - Disorders of the Anterior Segment Flashcards

(104 cards)