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PubMed This is a summary of 5 peer-reviewed journal articles Updated
Ophthalmology

The Silent Risk: Eye Health and Glaucoma in NPS

At a Glance

Individuals with Nail-Patella Syndrome (NPS) have a high lifelong risk of developing glaucoma due to LMX1B gene mutations. Because early glaucoma typically has no symptoms, routine screening by an ophthalmologist is critical to prevent permanent vision loss.

While the “Nail” and “Patella” parts of this condition’s name are well-known, the eyes are a critical third area that requires lifelong attention. Because the LMX1B gene is responsible for building the structures at the front of the eye, mutations can lead to physical changes that increase the risk of vision loss if not monitored carefully [1].

What is Glaucoma?

Glaucoma is a group of eye conditions that damage the optic nerve, the vital link that sends visual information from the eye to the brain. This damage is usually caused by abnormally high pressure inside the eye (intraocular pressure).

Think of the eye like a sink with a faucet and a drain:

  • The eye constantly produces a clear fluid to stay healthy.
  • In a healthy eye, this fluid drains out at the same rate it is produced.
  • In NPS, the “drainage system” may be narrow or poorly formed because of the LMX1B blueprint error [2].
  • When fluid cannot drain properly, pressure builds up, much like a clogged sink, and begins to press against the optic nerve.

The “Silent Thief of Sight”

Glaucoma is often called the “silent thief of sight” because it usually has no symptoms in the early stages [2]. There is typically no pain, no redness, and no immediate change in vision. By the time a person notices “tunnel vision” or blurring, permanent damage to the optic nerve may have already occurred. This is why regular screening is the only way to catch it early.

Types of Glaucoma in NPS

People with NPS are at risk for two main types of glaucoma:

  1. Open-Angle Glaucoma: This is the most common form in NPS and often starts at an earlier age than in the general population [2]. The “drain” looks open, but it doesn’t work efficiently.
  2. Angle-Closure Glaucoma: This is less common but can be more sudden. It happens when the space between the iris and the cornea is too narrow, physically blocking the drain [3][2].

Lester’s Sign: A Unique Iris Marker

Many people with NPS have a unique feature called Lester’s sign (also known as a Lester iris) [4]. This is a star-shaped or “cloverleaf” area of darker pigment in the center of the iris (the colored part of the eye). While Lester’s sign does not cause any vision problems itself, it is a very helpful clue for doctors to confirm a diagnosis of NPS [4].

The Importance of Routine Screening

Because the risk of glaucoma is lifelong, consistent eye care is essential. Experts recommend a baseline exam with an ophthalmologist (a medical eye doctor) as soon as the NPS diagnosis is made, followed by regular check-ups [5].

A thorough NPS eye exam should include:

  • Tonometry: A quick test to measure the pressure inside the eye.
  • Gonioscopy: A specialized lens used to look at the “drainage angle” of the eye to see if it is open or narrow [2].
  • Ophthalmoscopy: Examining the back of the eye to look for “cupping” or changes to the optic nerve [2][4].
  • Visual Field Test: A test that checks peripheral (side) vision, which is often the first area affected by glaucoma.

If glaucoma is detected, it is highly treatable with daily eye drops or minor procedures to lower the pressure and protect the optic nerve for life.

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Common questions in this guide

Why do people with Nail-Patella Syndrome need regular eye exams?
People with NPS have an LMX1B gene mutation that can affect how the eye is structured, causing a lifelong, elevated risk of glaucoma. Regular screening with an ophthalmologist is essential because early glaucoma typically has no warning signs or symptoms.
What is Lester's sign in NPS?
Lester's sign, or a Lester iris, is a unique star-shaped or cloverleaf area of darker pigment in the center of the colored part of the eye. While it doesn't cause vision problems on its own, it is a key feature that helps doctors confirm an NPS diagnosis.
How does Nail-Patella Syndrome cause glaucoma?
In NPS, the eye's drainage system may be narrow or poorly formed. When fluid cannot drain properly, pressure builds up inside the eye and damages the optic nerve, which can lead to permanent vision loss if left untreated.
What tests are used to check for glaucoma in Nail-Patella Syndrome?
A thorough eye exam for NPS should include tonometry to measure intraocular pressure, gonioscopy to check the drainage angle, ophthalmoscopy to examine the optic nerve, and visual field testing to check for early peripheral vision loss.
What are the symptoms of glaucoma in NPS?
Glaucoma is known as the 'silent thief of sight' because it usually causes no pain, redness, or vision changes in its early stages. As the condition progresses, a person might begin to experience blurred vision, halos around lights, or tunnel vision.

Questions to Ask Your Doctor

Curated prompts to bring to your next appointment.

  1. 1.What was my child's intraocular pressure (IOP) during today's exam, and what is considered a 'normal' range for them?
  2. 2.Did you see 'Lester's sign' or any other specific iris changes during the slit-lamp exam?
  3. 3.Is the drainage angle in my child's eye open or narrow (gonioscopy), and how does that affect their risk for angle-closure glaucoma?
  4. 4.At what age do you recommend starting visual field testing to ensure there is no silent vision loss?
  5. 5.How often should we return for follow-up eye exams if today's baseline results are normal?

Questions For You

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References

References (5)
  1. 1

    Internal Carotid Artery Aplasia in a Patient With Nail-Patella Syndrome.

    Kraus J, Jahngir MU, Singh B, Qureshi AI

    Vascular and endovascular surgery 2020; (54(2)):175-181 doi:10.1177/1538574419888345.

    PMID: 31746280
  2. 2

    Nail-Patella Syndrome and Glaucoma: A Case Report and Review of the Literature.

    Pallozzi Lavorante N, Iester M, Bonzano C, et al.

    Case reports in ophthalmology 2022; (13(3)):984-990 doi:10.1159/000527234.

    PMID: 36605036
  3. 3

    Plateau iris syndrome and angle-closure glaucoma in a patient with nail-patella syndrome.

    Gardin MA, Khor CC, Silva L, et al.

    American journal of ophthalmology case reports 2020; (20()):100886 doi:10.1016/j.ajoc.2020.100886.

    PMID: 32954044
  4. 4

    Nail-Patella Syndrome: Optical Coherence Tomography Angiography Findings.

    Zuberi HZ, Angirekula A, Akram MR, Kooner KS

    Case reports in ophthalmology 2022; (13(1)):227-233 doi:10.1159/000523984.

    PMID: 35611018
  5. 5

    Letter to the editor in reponse to Louboutin, Wascher, and Neyret in management of patellar problems in skeletally mature patients with nail-patella syndrome. KSSTA 2017 Oct;25(10):3012-3016. https://doi.org/10.1007/s00167-016-4044-y. Epub 2016 Feb 12.

    Koëter S, Tigchelaar S, Bongers E

    Knee surgery, sports traumatology, arthroscopy : official journal of the ESSKA 2021; (29(3)):1006-1007 doi:10.1007/s00167-018-4911-9.

    PMID: 29594322

This page provides educational information about eye health and glaucoma risks in Nail-Patella Syndrome. It does not replace professional medical advice or the need for routine eye exams by a qualified ophthalmologist.

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