Peripheral Retinal Degenerations and Rhegmatogenous Retinal Detachment
Peripheral Retinal Abnormalities
Each peripheral retinal abnormality poses a different level of risk for retinal detachment. Some of these lesions may be inconsequential manifestations, whereas others represent a high risk for detachment, particularly in patients with high myopia; aphakia or pseudophakia; previous detachment in the fellow eye; or a strong family history of retinal detachment.
Lattice degeneration is a common peripheral vitreoretinal disorder present in 6-10% of the population. While only 0.5-1% of eyes with lattice degeneration will develop a retinal detachment, approximately 20-30% of patients with rhegmatogenous retinal detachments have lattice degeneration. Lattice degeneration has many morphologies, the most common being circumferentially oriented localized round, linear, or ovoid areas of retinal thinning that are sometimes crossed by whitish lines that represent hyalinized retinal vessels. Other features include superficial whitish yellow flecks; patches of varying degrees of pigmentation; round or linear red craters; round or linear white patches; and small atrophic round holes. On histopathologic examination, lattice degeneration consists of one of three findings: a localized thinning of the inner retinal layers, vitreous liquefaction overlying thinned retina, and vitreous condensation with exaggerated vitreo-retinal attachments at the margins of the lesion. Although lattice degeneration itself is asymptomatic, it can be associated with retinal tears, detachments, or traction, which may cause floaters, photopsias, or other visual disturbances. In some eyes with lattice degeneration, retinal detachment may occur secondary to retinal tears that develop in areas remote from the lattice degeneration. General practice patterns generally recommend observation for asymptomatic lattice degeneration and only consider treatment of the condition in cases where the fellow eye had a previous retinal detachment.
Retinal Tears and Localized Detachments
A rhegmatogenous retinal detachment (RRD) is a sight-threatening condition that occurs in approximately 1 in 10,000 people. Lattice degeneration is the greatest risk factor, but pathologic myopia, previous intraocular surgery, trauma, and family or personal history of retinal detachment are also risk factors. An RRD occurs when fluid accumulates between the sensory retina and retinal pigment epithelium (RPE) through a retinal break caused by vitreous traction. An RRD generally has a classic corrugated appearance and undulates with eye movements. A variety of treatment modalities have evolved to repair RRD, and these include the traditional use of a scleral buckle, pars plana vitrectomy surgery (PPV), or pneumatic retinopexy (PR). Each treatment will influence the appearance of the fundus following treatment, though the general principles for all procedures are essentially the same. The essential steps for repairing RRD are (1) detection of the retinal breaks, (2) closure of the defects, (3) release of vitreous traction, and (4) placement of an adhesive modality (generally photocoagulation and/or cryotherapy). This generally allows for resultant apposition of the retina to the underlying RPE. The most common cause of detachment repair failure, which occurs in 8-10% of patients, is proliferative vitreoretinopathy (PVR), which may require reoperation. There is always the possibility of missing or not fully treating the retinal pathology as well.
Chronic Retinal Detachment With Demarcation Lines
Chronic Retinal Detachment with Retinal Macrocyst
Retinal Dialysis and Giant Retinal Tear (GRT)
A full-thickness retinal break that involves three or more clock hours is considered a giant retinal tear (GRT). GRTs may be associated with hereditary conditions including Marfan syndrome, Stickler syndrome, and high myopia, though may also occur spontaneously, or result from trauma. Between 80 and 90% of GRTs occur in males.
A retinal dialysis is a tear of the retina that results in disinsertion from the ora serrata. Most retinal dialyses are secondary to trauma and are seen most commonly in the inferotemporal quadrant.