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PubMed This is a summary of 18 peer-reviewed journal articles Updated
Ophthalmology

Beyond the Iris: How Aniridia Affects the Whole Eye

At a Glance

Aniridia is a pan-ocular disorder that affects almost every structure in the eye, not just the missing iris. Children with aniridia require lifelong monitoring for vision-threatening complications, including aniridia-associated keratopathy (AAK), early cataracts, silent glaucoma, and foveal hypoplasia.

The word “aniridia” describes the absence of the iris, but it doesn’t tell the whole story. Doctors refer to aniridia as a pan-ocular disorder because it affects almost every structure within the eye [1][2]. While the missing iris is what you see on the surface, the challenges to vision often lie deeper within the eye’s anatomy.

The Front of the Eye: The Surface and Pressure

As children with aniridia grow, the front part of the eye (the anterior segment) undergoes several changes.

Aniridia-Associated Keratopathy (AAK)

The cornea is the clear, protective window at the front of the eye. To stay clear, it relies on a “niche” of special cells called limbal stem cells [3][4]. In aniridia, these stem cells are often deficient. Over time, this leads to Aniridia-Associated Keratopathy (AAK), where the cornea begins to lose its transparency and becomes cloudy or scarred [1][5].

  • When it starts: While some infants (about 13%) are born with some cloudiness, AAK is typically a progressive condition that becomes more noticeable after age 10 [5][6].
  • Management: Doctors often recommend preservative-free lubricating drops early on to protect the surface and delay the progression of this cloudiness [7].

Glaucoma

Glaucoma is a condition where the internal pressure of the eye becomes too high, potentially damaging the optic nerve [8]. In aniridia, the drainage system of the eye is often underdeveloped or becomes blocked over time. Glaucoma is often “silent,” meaning it doesn’t cause pain, so regular pressure checks are vital as your child matures [9][10].

A Note on Measuring Eye Pressure: Measuring intraocular pressure (IOP) in aniridia is uniquely challenging. Because the cornea often has an abnormal central corneal thickness (CCT) and may develop scarring from AAK, standard pressure-checking tools can give highly inaccurate readings [1][8]. Specialists often need to use specialized tools (like a rebound tonometer) and physically measure the corneal thickness (pachymetry) to get a true reading.

The Middle of the Eye: The Lens

The lens is responsible for focusing light onto the back of the eye. In patients with aniridia, the lens may develop cloudiness, known as a cataract [11]. These can develop early in life and may eventually require surgery to improve vision. However, surgeons approach these cases with extra care because surgery can sometimes negatively affect the health of the cornea or eye pressure [8][12].

The Back of the Eye: The Retina and Vision

The most significant impact on a child’s visual acuity (how clearly they see) often comes from the back of the eye, specifically the retina.

Foveal Hypoplasia

The fovea is a small pit in the center of the retina responsible for sharp, detailed vision. In aniridia, the fovea often does not develop fully—a condition called foveal hypoplasia [1][13].

  • Visual Clarity: The severity of this underdevelopment is the primary factor in determining a child’s “best” vision [13][14].
  • Nystagmus: Because the brain isn’t receiving a sharp image from the fovea, the eyes may “wiggle” or shake involuntarily as they try to find a clear focus. This is called nystagmus [15][16]. While it can be startling for parents to see, it is a common symptom in infancy.

Infancy vs. Later Complications

It is helpful to distinguish between what you see now and what your medical team will monitor for in the future.

Stage Common Features
Infancy (Present Now) Missing iris, photophobia (light sensitivity), and nystagmus (shaking eyes) [1][17].
Childhood/Adulthood (Long-term Monitoring) Progressive corneal clouding (AAK), development of cataracts, and increasing eye pressure (glaucoma) [8][1].

Understanding that aniridia is a lifelong, pan-ocular journey helps you and your care team stay proactive in protecting your child’s vision at every stage of their growth [1][18].

Common questions in this guide

Why do my child's eyes shake or wiggle with aniridia?
The shaking, known as nystagmus, happens because the fovea at the back of the eye doesn't fully develop. The brain struggles to receive a sharp image, causing the eyes to make continuous, involuntary movements to try and find a clear focus.
How is eye pressure checked in children with aniridia?
Measuring eye pressure in aniridia requires specialized care because the cornea often has an abnormal thickness and potential scarring. Eye doctors frequently use specific tools like a rebound tonometer and physically measure the corneal thickness to ensure accurate readings for glaucoma.
What can I do to protect my child's cornea from aniridia-associated keratopathy (AAK)?
Doctors often recommend using preservative-free lubricating eye drops starting early in life. These drops help protect the eye's delicate surface, compensate for stem cell deficiencies, and may delay the progression of corneal cloudiness and scarring.
Will my child develop cataracts if they have aniridia?
Children with aniridia are at a higher risk of developing early cataracts, which is a clouding of the eye's focusing lens. While surgery is an option to improve vision, it requires careful specialist planning because the procedure can sometimes negatively affect the cornea or eye pressure.
What is foveal hypoplasia in aniridia?
Foveal hypoplasia is the underdevelopment of the fovea, the small pit in the retina responsible for sharp, detailed central vision. The severity of this underdevelopment is the primary factor that determines a child's best possible visual clarity.

Questions to Ask Your Doctor

Curated prompts to bring to your next appointment.

  1. 1.What is the 'Thomas Grade' or severity level of my child's foveal hypoplasia?
  2. 2.Given the structural differences in my child's cornea, are you using a specialized tonometer or measuring corneal thickness to get accurate eye pressure readings?
  3. 3.When should we expect to see the first signs of cataracts, and how will they be managed?
  4. 4.Are there specific preservative-free eye drops we should use now to protect the corneal surface?

Questions For You

Tap a prompt to share your answer — we'll use it plus this page's context to start a tailored conversation.

References

References (18)
  1. 1

    [Glaucoma in PAX6-related congenital aniridia: A review of the literature].

    Bastelica P, Daruich A, Paganelli B, et al.

    Journal francais d'ophtalmologie 2025; (48(1)):104300 doi:10.1016/j.jfo.2024.104300.

    PMID: 39368260
  2. 2

    A rare case of congenital aniridia with an unusual run-on mutation in PAX6 gene.

    Ratna R, Tibrewal S, Gour A, et al.

    Indian journal of ophthalmology 2022; (70(7)):2661-2664 doi:10.4103/ijo.IJO_433_22.

    PMID: 35791194
  3. 3

    Dysfunction of the limbal epithelial stem cell niche in aniridia-associated keratopathy.

    Schlötzer-Schrehardt U, Latta L, Gießl A, et al.

    The ocular surface 2021; (21()):160-173 doi:10.1016/j.jtos.2021.06.002.

    PMID: 34102310
  4. 4

    Decreased FABP5 and DSG1 protein expression following PAX6 knockdown of differentiated human limbal epithelial cells.

    Katiyar P, Stachon T, Fries FN, et al.

    Experimental eye research 2022; (215()):108904 doi:10.1016/j.exer.2021.108904.

    PMID: 34954205
  5. 5

    Corneal Abnormalities in Congenital Aniridia: Congenital Central Corneal Opacity Versus Aniridia-associated Keratopathy.

    Lee HK, Kim MK, Oh JY

    American journal of ophthalmology 2018; (185()):75-80 doi:10.1016/j.ajo.2017.10.017.

    PMID: 29101006
  6. 6

    Rare association of aniridia with congenital aphakia and secondary glaucoma.

    Alharbi S, Albishri A, Owaidhah O

    Saudi journal of ophthalmology : official journal of the Saudi Ophthalmological Society 2021; (35(4)):360-361 doi:10.4103/1319-4534.347313.

    PMID: 35814998
  7. 7

    Secondary Data Analysis of Inflammation-Related mRNAs in Conjunctival Impression Cytology Samples of Aniridia Patients.

    Stachon T, Latta L, Fries FN, et al.

    Cornea 2024; (43(5)):627-634 doi:10.1097/ICO.0000000000003454.

    PMID: 38147570
  8. 8

    Clinical outcomes and visual prognostic factors in congenital aniridia.

    Jacobson A, Mian SI, Bohnsack BL

    BMC ophthalmology 2022; (22(1)):235 doi:10.1186/s12886-022-02460-5.

    PMID: 35614435
  9. 9

    Short- and Long-term Results of Glaucoma Valve Implantation for Aniridia-related Glaucoma: A Case Series and Literature Review

    Soyugelen Demirok G, Ekşioğlu Ü, Yakın M, et al.

    Turkish journal of ophthalmology 2019; (49(4)):183-187 doi:10.4274/tjo.galenos.2019.07348.

    PMID: 31486604
  10. 10

    Prevalence, Incidence, and Risk Factors for the Development of Glaucoma in Patients With Aniridia.

    Balekudaru S, Sankaranarayanan N, Agarkar S

    Journal of pediatric ophthalmology and strabismus 2017; (54(4)):250-255 doi:10.3928/01913913-20170322-01.

    PMID: 28510772
  11. 11

    Crystalline lens alterations in congenital aniridia.

    D'Oria F, Barraquer R, Alio JL

    Archivos de la Sociedad Espanola de Oftalmologia 2021; doi:10.1016/j.oftal.2020.12.016.

    PMID: 33612366
  12. 12

    The Effect of Lens Properties on Visual Acuity, Aniridia Associated Keratopathy and Secondary Glaucoma in Congenital Aniridia Subjects.

    Náray A, Fries FN, Munteanu C, et al.

    Current eye research 2025; (50(4)):381-393 doi:10.1080/02713683.2024.2438687.

    PMID: 39687987
  13. 13

    Spectral-domain optical coherence tomography foveal morphology as a prognostic factor for vision performance in congenital aniridia.

    Casas-Llera P, Siverio A, Esquivel G, et al.

    European journal of ophthalmology 2020; (30(1)):58-65 doi:10.1177/1120672118818352.

    PMID: 30556423
  14. 14

    Normal and abnormal foveal development.

    Thomas MG, Papageorgiou E, Kuht HJ, Gottlob I

    The British journal of ophthalmology 2022; (106(5)):593-599 doi:10.1136/bjophthalmol-2020-316348.

    PMID: 33148537
  15. 15

    Nystagmus Characteristics in Albinism: Unveiling the Link to Foveal Hypoplasia and Visual Acuity.

    Talsma HE, Kruijt CC, de Wit GC, et al.

    Investigative ophthalmology & visual science 2023; (64(15)):30 doi:10.1167/iovs.64.15.30.

    PMID: 38133506
  16. 16

    The pathogenicity of SLC38A8 in five families with foveal hypoplasia and congenital nystagmus.

    Weiner C, Hecht I, Rotenstreich Y, et al.

    Experimental eye research 2020; (193()):107958 doi:10.1016/j.exer.2020.107958.

    PMID: 32032626
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    [Congenital aniridia in children].

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    Exploring the human experience of congenital aniridia: A narrative medicine approach.

    Ancona C, Marini MG, Minetti F, et al.

    European journal of ophthalmology 2026; (36(3)):601-608 doi:10.1177/11206721251407851.

    PMID: 41400928

This page is for educational purposes only and does not replace professional medical advice. Always consult a pediatric ophthalmologist regarding your child's specific vision needs, eye pressure measurements, and treatment plans.

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