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CASE REPORT
Year : 2021  |  Volume : 59  |  Issue : 2  |  Page : 187-189

Axenfeld's anomaly with ocular hypertension: A case report and review of literature


Glaucoma Services, Aravind Eye Hospital, Puducherry, India

Date of Submission02-Feb-2021
Date of Acceptance01-Apr-2021
Date of Web Publication24-Jun-2021

Correspondence Address:
Dr. Kavitha Srinivasan
Glaucoma Services, Aravind Eye Hospital, Cuddalore Main Road, Thavalakuppam, Puducherry - 605 007
India
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Source of Support: None, Conflict of Interest: None


DOI: 10.4103/tjosr.tjosr_13_21

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  Abstract 


Anterior segment dysgenesis refers to a spectrum of developmental anomalies which occurs due to aberration in the migration and differentiation of the neural crest cells. Here, we describe a young male who was referred for ophthalmic evaluation by a general physician with a white ring at the corneo-scleral junction. He had 6/6 vision but with raised intraocular pressure in both eyes. Slit-lamp evaluation revealed posterior embryotoxon and fundus examination showed no optic nerve damage. Gonioscopy revealed a prominent Schwalbe's line with multiple irido-trabecular adhesions suggestive of Axenfeld anomaly. Patients with Axenfeld anomaly are at increased risk of developing glaucoma in late childhood or early adulthood. Patients with such anomalous findings should be evaluated and followed up for glaucoma.

Keywords: Axenfeld's anomaly, posterior embryotoxon, secondary glaucoma


How to cite this article:
Odayappan A, Srinivasan K. Axenfeld's anomaly with ocular hypertension: A case report and review of literature. TNOA J Ophthalmic Sci Res 2021;59:187-9

How to cite this URL:
Odayappan A, Srinivasan K. Axenfeld's anomaly with ocular hypertension: A case report and review of literature. TNOA J Ophthalmic Sci Res [serial online] 2021 [cited 2021 Aug 5];59:187-9. Available from: https://www.tnoajosr.com/text.asp?2021/59/2/187/319249




  Introduction Top


A white ring at the limbus with peripheral iris tissue strands extending to it was first described as posterior embryotoxon by the German ophthalmologist Theodor Axenfeld in 1920. Rieger reported iris anomalies such as corectopia, iris atrophy, and iris holes in addition to the similar white ring at the limbus. He suggested this to be due to mesodermal dysgenesis of the cornea and iris.[1] Some of these patients also have other nonocular developmental defects of facial bones and teeth.

We are reporting a patient with Axenfeld's anomaly with secondary ocular hypertension who was diagnosed early, started on medication, and is on regular follow-up, thereby avoiding the consequence of irreversible blindness due to glaucoma at a young age.


  Case Report Top


A 21-year-old male was referred by a general physician for ophthalmic evaluation with a white ring at the corneo-scleral junction suspecting arcus juvenilis. On examination, his uncorrected visual acuity was 6/6 in both eyes. The intraocular pressure was 30 mmHg in the right eye and 28 mmHg in the left eye. Slit-lamp evaluation revealed bilateral posterior embryotoxon [Figure 1]. Fundus examination showed healthy optic nerves in both eyes. Gonioscopy revealed a prominent Schwalbe's line with bands of iris tissue extending across the anterior chamber angle and attaching to the Schwalbe's line [Figure 2]. There were no iris malformations or systemic anomalies. He was therefore diagnosed as Axenfeld's anomaly.
Figure 1: Posterior embryotoxon (red arrow) which is an anteriorly displaced Schwalbe's line

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Figure 2: Gonioscopic picture shows a prominent Schwalbe's line (red arrow) and adhesions of the iris to the anteriorly displaced Schwalbe's line (yellow arrow)

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He was prescribed Timolol eye drops twice a day in both eyes. On follow-up after a month, his uncorrected visual acuity was 6/6 and the intraocular pressure was 18 mmHg in both eyes. Anterior segment and fundus examination were similar to the previous visit. He was advised to continue timolol eye drops twice a day. He has been on regular follow-up for more than 2 years now. His intraocular pressure is being maintained well within normal levels with topical timolol.


  Discussion Top


Anterior segment dysgenesis refers to a spectrum of developmental anomalies, resulting from abnormalities of migration and differentiation of the neural crest cells. This encompasses congenital glaucoma,  Axenfeld-Rieger syndrome More Details (ARS), Peters anomaly, iris hypoplasia, iridoschisis, posterior keratoconus, congenital hereditary endothelial dystrophy, megalocornea, and sclerocornea.[2]

The current nomenclature in the spectrum of ARS states that if there are only peripheral anterior segment defects, it is referred to as Axenfeld's anomaly. The prominent anteriorly displaced Schwalbe's line is called the posterior embryotoxon. When there are additional iris changes such as corectopia, iris atrophy, hypoplasia, iris holes, polycoria, and ectropion uveae, it is called as Rieger's anomaly. The Presence of nonocular developmental defects such as dental anomalies, craniofacial dysmorphism, and umbilical abnormalities with the ocular anomalies constitutes ARS.[1] Glaucoma may occur in about half the cases due to incomplete development of the trabecular meshwork and Schlemm's canal (trabeculodysgenesis).[1]

ARS is inherited in an autosomal dominant manner. The prevalence is estimated to be around 1 in 50,000–100,000 newborns. Mutations in two major genes – pituitary homeobox 2 at 4q25 or Forkhead box protein C1 at 6p25 have been associated with ARS.[3],[4]

Rieger suggested that the pathogenesis is due to mesodermal dysgenesis. However, recent investigations suggest that neural crest cells are involved. In normal fetal development, the primordial layer which extends from the corneal endothelium to the peripheral iris disappears during or before the posterior recession of the peripheral iris and this usually occurs in the third trimester. In ARS, there is retention of the primordial endothelium and incomplete posterior recession of the peripheral iris.

Schwalbe's line is the transition from the corneal endothelium to the trabecular endothelium. In ARS, the primordial endothelium at the corneo-scleral region exhibits abnormal behavior, resulting in central displacement of this junction, leading to a prominent Schwalbe's line.[5]

Contraction of the retained endothelium leads to corectopia, ectropion uveae toward the side of the contraction and iris thinning, atrophy, and holes on the opposite side. These changes continue even after birth explaining how the progression of this congenital anomaly occurs later in life. Most cases of ARS are diagnosed in infancy or childhood; however, glaucoma typically occurs later in adolescence or early adulthood. The ocular involvement is mostly bilateral; however, it can be asymmetrical.

The neural crest cells also give rise to most of the mesenchyme related to the forebrain, pituitary gland, bones, cartilage of the upper face, and dental papillae. This explains the systemic nonocular manifestations of ARS. Dental anomalies include microdontia, hypodontia, oligodontia, anodontia, and cone-shaped teeth. Craniofacial dysmorphism includes prominent forehead, hypertelorism, telecanthus, flattened mid-face with a broad, flat nasal bridge, maxillary hypoplasia, receding upper lip, and prominent lower lip. Other systemic features reported include anal stenosis, hypospadias, pituitary abnormalities, growth hormone deficiency, short stature, primary empty sella syndrome, arachnoid cysts, oculocutaneous albinism, sensorineural hearing loss, and cardiac abnormalities.[3],[4] [Table 1] differentiates ARS, posterior polymorphous dystrophy, and iridocorneal endothelial syndrome.
Table 1: Differences between axenfeld rieger syndrome, posterior polymorphous dystrophy, and iridocorneal endothelial syndrome[5]

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Medical therapy to lower the intraocular pressure should be tried before surgical intervention. Beta blockers and carbonic anhydrase inhibitors are safer and effective. Prostaglandin analogues may be used. Alpha agonist (brimonidine) is contraindicated in very young children as it causes bradycardia, hypotension, apnea, and central nervous system depression. Pilocarpine may cause accommodation spasm and may increase the tendency for collapse of the trabecular meshwork, thereby paradoxically reducing the aqueous outflow.[5] Lasers such as Selective laser trabeculoplasty (SLT) should be avoided due to anomalous angles. The presence of iridocorneal strands and high insertion of the iris interferes with trabeculoplasty.[5]

In infants, usually, a goniotomy or trabeculotomy is indicated. In older children, medical management is tried first. Trabeculectomy with antimetabolite or a combined trabeculectomy with trabeculotomy is performed if necessary. Glaucoma drainage device is considered in refractory patients.[5]

Considering that such patients are at an increased risk of developing glaucoma in adolescence or early adulthood, they need regular follow-up for early detection of glaucoma. The ocular hypertension secondary to Axenfeld's anomaly in our patient was diagnosed and treated with hypotensive medication at an appropriate time before glaucomatous optic nerve head changes appeared. Monitoring him regularly with appropriate timely interventions will prevent irreversible blindness due to glaucoma. The study adhered to the tenets of the Declaration of Helsinki. Informed consent was obtained from the patient.

Declaration of patient consent

The authors certify that they have obtained all appropriate patient consent forms. In the form, the patient has given his consent for his images and other clinical information to be reported in the journal. The patient understands that name and initials will not be published and due efforts will be made to conceal identity, but anonymity cannot be guaranteed.

Financial support and sponsorship

Nil.

Conflicts of interest

There are no conflicts of interest.



 
  References Top

1.
Shields MB. Axenfeld-Rieger syndrome: A theory of mechanism and distinctions from the iridocorneal endothelial syndrome. Trans Am Ophthalmol Soc 1983;81:736-84.  Back to cited text no. 1
    
2.
Idrees F, Vaideanu D, Fraser SG, Sowden JC, Khaw PT. A review of anterior segment dysgeneses. Surv Ophthalmol 2006;51:213-31.  Back to cited text no. 2
    
3.
Seifi M, Walter MA. Axenfeld-Rieger syndrome. Clin Genet 2018;93:1123-30.  Back to cited text no. 3
    
4.
Tümer Z, Bach-Holm D. Axenfeld-Rieger syndrome and spectrum of PITX2 and FOXC1 mutations. Eur J Hum Genet 2009;17:1527-39.  Back to cited text no. 4
    
5.
Shields MB, Buckley E, Klintworth GK, Thresher R. Axenfeld-Rieger syndrome. A spectrum of developmental disorders. Surv Ophthalmol 1985;29:387-409.  Back to cited text no. 5
    


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