Lattice dystrophy is a rare inherited eye condition that affects the cornea, the clear, dome-shaped front surface of the eye. It involves the accumulation of abnormal protein fibers, known as amyloid deposits, within the corneal tissue. These deposits can progressively interfere with vision by causing cloudiness and discomfort. The disease is typically passed down through families and can manifest with varying degrees of severity and specific characteristics depending on its type.
Understanding Lattice Dystrophy
Lattice dystrophy primarily impacts the stroma, the third and thickest layer of the cornea. Within this layer, amyloid deposits gradually build up. These deposits are initially clear and can appear comma-shaped with branching threads and small dots, resembling a lattice pattern, which gives the condition its name.
Over time, these lattice-like fibers become denser and more opaque, spreading throughout the stroma. This increasing density causes the cornea to become cloudy, reducing vision. While lattice dystrophy can appear at any age, it often begins in childhood, between the ages of two and seven years.
Recognizing Symptoms and Diagnosis
Individuals with lattice dystrophy often experience a gradual reduction in vision as the cornea becomes cloudy. A painful symptom is recurrent epithelial erosions, which occur when the outermost layer of the cornea, the epithelium, breaks down. These erosions can alter the cornea’s shape and expose underlying corneal nerves, leading to intense pain, with even blinking being painful.
An ophthalmologist can diagnose lattice dystrophy during a routine eye examination. The characteristic lattice-like protein deposits are visible during this examination. Diagnosis may also involve unique clinical features or genetic testing to differentiate it from other similar eye conditions.
Genetic Basis and Types
Lattice dystrophy is a genetically inherited eye condition, classified into different types, each linked to specific genetic mutations and unique features.
Lattice Dystrophy Type 1 (LCD1)
This is the most common form, inherited in an autosomal dominant pattern and caused by a mutation in the TGFBI gene. LCD1 typically appears in childhood or early adulthood, with amyloid deposits usually confined to the central cornea.
Other Types of Lattice Dystrophy
Lattice Dystrophy Type 2 (LCD2), also known as Meretoja’s syndrome or Finnish type amyloidosis, is a rarer form inherited in an autosomal recessive pattern. This type is caused by a mutation in the GSN gene and is associated with systemic amyloidosis, meaning amyloid deposits can affect other organs beyond the eyes, such as nerves and skin. Lattice Dystrophy Type 3 (LCD3) is a very rare autosomal dominant form caused by a mutation in the APOA1 gene, usually presenting in adulthood with coarser amyloid deposits. Lattice Dystrophy Type 4 (LCD4) is another very rare autosomal dominant form, resulting from a mutation in the ITGBL1 gene, also typically manifesting in adulthood.
Management and Outlook
Management of lattice dystrophy depends on the condition’s severity and symptoms. For mild cases or to alleviate recurrent corneal erosions, medical treatments such as lubricating eye drops and ointments may be prescribed. Bandage contact lenses can also be used to protect the cornea and promote healing.
In more severe cases, surgical interventions may be necessary to improve vision. Phototherapeutic keratectomy (PTK) is a laser procedure that can remove superficial amyloid deposits from the cornea. When vision is significantly impaired, a corneal transplantation, also known as keratoplasty, may be performed to replace the diseased corneal tissue. While corneal transplantation has a high success rate, the disease can recur in the donor corneal tissue, usually within 2 to 14 years. Early detection of recurrence generally responds well to treatment.
Lattice dystrophy is a progressive disease that can lead to significant vision loss if unmanaged. While epithelial erosions typically heal within two to three days, some pain may persist for up to eight weeks. Patients who develop the condition at a young age may experience corneal haze and severely impaired vision due to scarring under the epithelium. Despite its progressive nature, many patients can maintain good vision for many years with appropriate care and timely interventions.