Lattice Corneal Dystrophy

Lattice corneal dystrophy is a bilateral, progressive stromal dystrophy caused by abnormal deposition of amyloid within the corneal stroma, producing the characteristic branching, refractile linear lesions that give the condition its name and that are, in the right clinical context, pathognomonic on slit-lamp exam.

Its particular significance among the corneal stromal dystrophies is that one specific genetic subtype is not confined to the eye at all: it is a marker of a systemic amyloidosis syndrome that can affect nerves, skin, and other organs, making eye exam findings in this specific variant a genuine window into disease well beyond the cornea.

Genetics and Classification

Lattice type I (classic) — autosomal dominant, caused by mutations in TGFBI, confined to the cornea without systemic amyloid involvement
Lattice type II (Meretoja syndrome) — caused by mutations in GSN (gelsolin), part of a systemic amyloidosis syndrome that also produces cranial and peripheral neuropathy, characteristic facial skin changes (cutis laxa-like loose, sagging facial skin), and other systemic amyloid deposition; the corneal lattice lines in this variant are typically finer, less dense, and involve a different distribution than classic type I
Other, rarer variants and combined phenotypes have also been described, generally sharing the underlying theme of localized (or, in type II, systemic) amyloid deposition

The clinical importance of correctly distinguishing type I from type II lattice dystrophy is high: a patient with type II needs systemic evaluation and monitoring for progressive neuropathy and other amyloid-related organ involvement that a patient with isolated type I does not, making the ophthalmologist’s recognition of the specific corneal pattern a potential trigger for a much broader diagnostic workup.

Clinical Presentation

Type I lattice dystrophy typically presents in the first or second decade of life with recurrent corneal erosion episodes — often the earliest symptomatic manifestation, before the lattice lines themselves are dense enough to significantly affect vision — followed by gradual visual decline over subsequent decades as amyloid deposition progressively clouds the central cornea.

Type II (Meretoja syndrome) tends to present somewhat later and progresses more slowly in terms of visual impact, though the systemic neuropathy in this variant can itself be significantly disabling independent of the ocular findings.

Exam Findings

Refractile, branching, linear opacities (the “lattice” lines) within the corneal stroma, most visible on retroillumination, typically sparing the peripheral cornea and most prominent centrally
Interspersed white-gray stromal haze between the lattice lines, which progressively increases and is what ultimately drives the visual decline as the disease advances
Recurrent epithelial erosions, particularly early in the disease course, following the same general principles discussed in this site’s dedicated article on recurrent corneal erosion syndrome
In type II specifically: additional signs of systemic amyloidosis on general exam — characteristic facial skin laxity, evidence of peripheral or cranial neuropathy (including, notably, facial nerve palsy in some patients), and other findings reflecting the systemic nature of this variant

Differential Diagnosis

Granular corneal dystrophy — discrete, sharply demarcated, breadcrumb-like deposits with clear intervening stroma, rather than the branching linear pattern of lattice dystrophy, discussed in its own dedicated article on this site
Macular corneal dystrophy — diffuse, cloudy stromal haze without the discrete linear or granular deposits of the other two classic stromal dystrophies, and notably the only one of the three inherited in an autosomal recessive rather than dominant pattern
Avellino (granular-lattice) corneal dystrophy — a combined phenotype showing features of both granular and lattice dystrophy, related to specific TGFBI mutation variants
Amyloid deposition from other, unrelated causes — generally distinguished by the specific clinical and family history context, and confirmed if needed by the same anti-amyloid histochemical staining used to characterize hereditary lattice dystrophy

Management

Recurrent corneal erosion episodes are managed with the same general approach used for that syndrome from any cause: aggressive lubrication as the first line, with more definitive interventions (anterior stromal micropuncture, phototherapeutic keratectomy) reserved for refractory cases, discussed in more detail in this site’s dedicated article on recurrent corneal erosion.

As stromal haze progressively affects vision, phototherapeutic keratectomy can provide temporary improvement by removing more superficial deposits, though the disease is progressive and deposits typically recur over subsequent years, given that the treatment addresses existing amyloid rather than the underlying ongoing deposition process.

Corneal transplantation (penetrating or, increasingly, deep anterior lamellar keratoplasty when the deposition is confined to the stroma without endothelial involvement) is eventually needed in many patients as the disease progresses.

However, a notable and clinically important feature of lattice dystrophy is that amyloid deposition can recur in the graft itself over subsequent years, because the underlying disease process — systemic in type II — is not cured by replacing the affected corneal tissue alone.

Patients with type II (Meretoja syndrome) require coordinated care with neurology and other relevant specialists for their systemic amyloid-related manifestations, extending management well beyond the eye alone.

References

Meretoja J. Familial systemic paramyloidosis with lattice dystrophy of the cornea, progressive cranial neuropathy, skin changes and various internal symptoms. Annals of Clinical Research.
Klintworth GK. Corneal dystrophies. Orphanet Journal of Rare Diseases.
American Academy of Ophthalmology. Basic and Clinical Science Course, Section 8: External Disease and Cornea.

Lattice Corneal Dystrophy: When Corneal Lines Signal Systemic Amyloidosis