Hypermobility and Eye Health: Ocular Manifestations, Diagnosis, and Management

Can hypermobility affect the eyes?

Yes, hypermobility, particularly when it stems from underlying connective tissue disorders like Ehlers-Danlos Syndromes (EDS) or Hypermobility Spectrum Disorder (HSD), can significantly affect the eyes due to the widespread role of collagen and other connective tissues throughout the body, including ocular structures.

Understanding Hypermobility

What is Hypermobility? Hypermobility refers to joints that move beyond the normal range of motion. While some individuals may have generalized joint hypermobility without any associated symptoms (asymptomatic hypermobility), for others, it can lead to chronic pain, fatigue, instability, and a range of systemic manifestations. This symptomatic form is often diagnosed as Hypermobility Spectrum Disorder (HSD) or, in more severe cases involving specific genetic mutations, as one of the types of Ehlers-Danlos Syndromes.

Hypermobility Spectrum Disorder (HSD) vs. Ehlers-Danlos Syndromes (EDS) Both HSD and EDS involve issues with connective tissue. EDS is a group of inherited disorders characterized by defects in collagen synthesis and structure, leading to fragile tissues throughout the body. Hypermobile EDS (hEDS) is the most common type of EDS and is diagnosed clinically. HSD is a diagnosis for individuals with symptomatic joint hypermobility who do not meet the full criteria for hEDS or any other specific connective tissue disorder. The underlying genetic mechanisms for HSD are still being researched, but it shares many clinical features with hEDS. The critical point for ocular involvement is the common denominator: altered connective tissue integrity.

The Connective Tissue Link

Collagen's Role in the Body Collagen is the most abundant protein in the human body, forming the primary structural component of connective tissues such as skin, tendons, ligaments, cartilage, bone, and blood vessel walls. It provides strength, elasticity, and structural integrity. In conditions like EDS and HSD, defects in collagen production or structure lead to weakened, stretched, or abnormally formed connective tissues throughout the body, accounting for the characteristic joint laxity, skin fragility, and systemic issues.

Collagen's Role in the Eye The eye is a complex organ heavily reliant on robust connective tissue for its structure and function. Key ocular structures containing collagen and other connective tissues include:

• Sclera: The tough, white outer layer of the eyeball, providing structural support.
• Cornea: The transparent front part of the eye that covers the iris, pupil, and anterior chamber, essential for focusing light.
• Lens: Suspended by suspensory ligaments, it focuses light onto the retina.
• Retina: The light-sensitive tissue at the back of the eye, supported by the vitreous humor (a gel-like substance containing collagen fibers).
• Optic Nerve: Its sheath contains connective tissue.
• Eyelids and Extraocular Muscles: Contain connective tissues that contribute to their integrity and function.

Alterations in the quality or quantity of collagen and other extracellular matrix components can therefore directly impact the structural integrity and function of various ocular tissues.

How Hypermobility Can Affect the Eyes

The systemic nature of connective tissue disorders means that the eyes are not exempt from their effects. Here are several ways hypermobility can manifest in ocular symptoms:

• Scleral Thinning and Blue Sclera The sclera, the white outer layer of the eye, is primarily composed of collagen. In individuals with compromised collagen, the sclera can be abnormally thin, allowing the underlying dark choroidal pigment to show through, resulting in a characteristic "blue sclera." This is a common finding in some types of EDS.

• Myopia (Nearsightedness) The sclera's structural weakness can allow the eyeball to stretch more easily, leading to an elongated axial length. This elongation causes light to focus in front of the retina, resulting in myopia or nearsightedness. High myopia is a frequent finding in individuals with EDS.

• Retinal Issues: Detachment and Lattice Degeneration The vitreous humor, a gel-like substance filling the eye, contains collagen fibers that are normally attached to the retina. In connective tissue disorders, the vitreous can be more prone to liquefaction and posterior vitreous detachment (PVD) at an earlier age. This can pull on the retina, potentially leading to retinal tears or detachment. Lattice degeneration, a thinning of the peripheral retina, is also more common and increases the risk of retinal detachment.

• Keratoconus and Corneal Ectasia The cornea, the transparent front window of the eye, relies on its collagenous structure to maintain its dome shape. In conditions affecting collagen, the cornea can progressively thin and bulge outwards into a cone shape, a condition known as keratoconus. This leads to irregular astigmatism, blurred vision, and light sensitivity. Similar conditions, broadly termed corneal ectasia, can also occur.

• Glaucoma and Ocular Hypertension While the link is complex and not fully understood, some studies suggest a higher prevalence of glaucoma or ocular hypertension (elevated pressure within the eye) in individuals with certain connective tissue disorders. This could be due to altered outflow pathways for aqueous humor or structural changes in the optic nerve head.

• Dry Eye Syndrome Connective tissue issues can affect the lacrimal glands and the structural integrity of the eyelids, potentially leading to reduced tear production or increased tear evaporation. This can result in chronic dry eye syndrome, causing irritation, redness, and discomfort.

• Strabismus and Binocular Vision Dysfunction The extraocular muscles that control eye movement, and their surrounding connective tissues, can be affected. This may contribute to strabismus (eye misalignment, e.g., crossed eyes or wandering eyes) or other forms of binocular vision dysfunction, where the eyes struggle to work together effectively, leading to symptoms like double vision, eye strain, and headaches.

• Ptosis (Drooping Eyelid) Weakness in the connective tissues supporting the eyelid, particularly the levator palpebrae superioris muscle and its aponeurosis, can lead to ptosis, a drooping of the upper eyelid. While often cosmetic, severe ptosis can obstruct vision.

Diagnosis and Management

Comprehensive Eye Examinations Given the potential for significant ocular involvement, individuals diagnosed with HSD or EDS, or those with symptomatic hypermobility, should undergo regular, comprehensive eye examinations by an ophthalmologist familiar with connective tissue disorders. These examinations should include:

• Visual acuity testing
• Refraction for myopia and astigmatism
• Slit-lamp examination to assess the cornea, lens, and anterior structures
• Fundus examination to check the retina and optic nerve, often with dilation
• Intraocular pressure measurement
• Corneal topography/pachymetry to screen for keratoconus
• Optical coherence tomography (OCT) for retinal and optic nerve assessment

Multidisciplinary Approach Management of ocular manifestations often requires a multidisciplinary approach involving ophthalmologists, geneticists, and other specialists. For example, keratoconus might be managed with corrective lenses, contact lenses, corneal collagen cross-linking, or, in severe cases, corneal transplantation. Retinal issues may require laser treatment or surgery.

Lifestyle Considerations Individuals with hypermobility should be cautious with activities that put undue strain on the eyes or involve head trauma. Avoiding eye rubbing is particularly important due to the risk of corneal thinning and keratoconus progression.

When to Seek Medical Attention

It's crucial for individuals with hypermobility to be aware of potential ocular symptoms and seek prompt medical attention if they experience:

• Sudden onset of new floaters or flashes of light (potential retinal detachment)
• A curtain-like shadow or loss of peripheral vision
• Sudden significant decrease in vision
• Persistent eye pain or redness
• Changes in the shape of the cornea or significant worsening of vision
• Double vision or difficulty focusing

Conclusion

Hypermobility, particularly when linked to underlying connective tissue disorders, can indeed affect the eyes through various mechanisms, primarily due to the ubiquitous role of collagen and other connective tissues in maintaining ocular structure and function. From changes in the sclera and cornea to increased risks of retinal detachment and specific vision problems, the ocular manifestations can be diverse. Regular, comprehensive ophthalmological care is essential for early detection, monitoring, and appropriate management to preserve vision and maintain ocular health in individuals with hypermobility.