Lattice Degeneration

Lattice degeneration occurs in 8-11% of the general population, as a linear trail of fibrosed vessels within atrophied retina in a "lattice" pattern. The underlying cause of lattice is not really known. The condition appears to be due to dropout of peripheral retinal capillaries with resulting insufficient blood supply (ischemia), which results in the thinning of all retinal layers. Larger blood vessels harden, their lumen fills with extracellular glial tissue, giving lattice degeneration its characteristic fibrotic appearance.

The retinal thinning has several effects:

• the overlying vitreous will be disturbed, resulting in a pocket of liquefaction overlying the lattice lesion known as a lacuna;
• the vitreous along the edges of the lattice lesion will undergo strong adhesion to the retina; and
• the ischemia and retinal thinning will disturb the retinal pigment epithelium, resulting in RPE hyperplasia and a pigmented appearance.

Often the thinning becomes so profound that a full-thickness hole atrophies through the retina at the lattice lesion. The overlying liquefied vitreous has the ability to pass through the hole into the subretinal space and possibly lead to rhegmatogenous retinal detachment. This will occur in approximately two percent of cases of holes within lattice degeneration. Due to the liquefaction of the overlying vitreous, there is no vitreoretinal traction on the edges of a hole in lattice degeneration. If a posterior vitreous detachment occurs, the vitreoretinal traction along the posterior edge of a lattice lesion may result in a linear tear, with an ensuing progression to rhegmatogenous retinal detachment in 37 percent of cases.

The incidence of atrophic holes in lattice degeneration ranges from 18 to 42 percent.

The patient is usually over age 20 and is nearly always asymptomatic, except for possible complaints of flashing lights (photopsia). There appears to be a higher incidence of myopia in patients with lattice degeneration. There is no racial or sexual predilection.

The underlying cause is not known.

There is no conventional solution. Lasers or cryoretinopexy are sometimes used prophylactically to help prevent retinal detachments.