Retinal tears most frequently develop from vitreous traction, often during a posterior vitreous detachment (PVD). Such tears are typically horseshoe in configuration, with an anterior retinal “flap” that is tightly adherent to the posterior hyaloid. Liquefied vitreous can travel through the tear and underneath the neurosensory retina, leading to subretinal fluid accumulation and creating a rhegmatogenous retinal detachment. Customarily, rhegmatogenous retinal detachments are described by their clock hours of involvement, and whether or not the macula is affected. Macula-involving retinal detachments are at higher risk for some level of persistent visual compromise once repaired. Risk factors for rhegmatogenous retinal detachment include acute PVD, lattice degeneration, ocular trauma, high myopia (defined as a spherical equivalent of –6.0 diopters or more, or an axial length of at least 26 mm), cataract surgery (especially in the setting of vitreous loss) and certain genetic syndromes (e.g., Stickler, Marfan, Ehlers Danlos, or Wagner syndrome). The incidence of primary rhegmatogenous retinal detachment is estimated to be around 12 in 10,000 people per year (0.01% annual risk). With appropriate surgical intervention, the single surgery anatomic success rate approaches 90%, but the visual prognosis varies.
12.1.1 Common Symptoms
Common symptoms include rapid, monocular photopsias that occur for a few seconds, floaters, the abrupt appearance of floaters, loss of peripheral vision (often noticed as a “curtain” or “shade” over vision), and potentially central vision loss. Flashes and floaters will often precede the onset of vision loss, and most often reflect the initial development of a retinal tear prior to the subsequent retinal detachment.
12.1.2 Exam Findings
Clinical examination reveals subretinal fluid with an associated retinal break(s) (although the retinal break[s] may not always be readily identifiable). Additional potential findings include pigmented cell in the anterior vitreous (Shaffer’s sign or tobacco dust), low intraocular pressure (due to drainage of subretinal fluid via sclerochoroidal drainage), one or more retinal breaks, areas of retinal thinning (lattice degeneration), and vitreous hemorrhage (often due to traction on a retinal vessel). Patients with chronic rhegmatogenous retinal detachments may exhibit proliferative vitreoretinopathy (PVR; due to unregulated proliferative of retinal pigment epithelial and glial cells, manifesting as starfolds, retinal contraction, retinal folds, or preretinal fibrosis), intraretinal cysts, retinal macrocysts, pigmented demarcation lines (reflecting RPE cells at the edge of slowly advancing subretinal fluid), and high intraocular pressure (due to Schwartz Matsuo syndrome where RPE cells block the trabecular meshwork).
12.2 Key Diagnostic Tests and Findings
12.2.1 Optical Coherence Tomography
Optical coherence tomography (OCT) may be helpful in diagnosis and is especially helpful to assess macular involvement. OCT can identify areas of shallow macular subretinal fluid and show its proximity to the fovea which may guide urgency of repair (▶ Fig. 12.1). Another potential finding with OCT includes the presence of a PVD, depending on the position of the posterior hyaloid. OCT can also show preexisting conditions such as epiretinal membrane, macular edema, macular degeneration, or myopic degeneration, which can be helpful to know preoperatively for visual prognosis. Postoperatively, OCT can be used to confirm resolution of subretinal fluid and evaluate the anatomic status of the fovea, including ellipsoid zone integrity and presence of cystoid macular edema.
Fig. 12.1 Optical coherence tomography in retinal detachment. (a) En face imaging reveals temporal subretinal fluid in the macula, (b) while the cross-sectional B-scan shows fluid underneath the temporal macula, encroaching the fovea.
12.2.2 Fundus Photography
With the advent of wide-angle imaging techniques, fundus photography is now being used increasingly to visualize/diagnose retinal detachments. Nonmydriatic widefield imaging may be particularly helpful for patients with poorly dilating pupils or nystagmus (▶ Fig. 12.2).
Fig. 12.2 Ultra-widefield fundus photograph of a macula-off retinal detachment. Fundus photography was used as an ancillary imaging tool due to a poorly dilating pupil and identified the superior retinal detachment.
Occasionally, a retinal detachment is obscured by dense vitreous hemorrhage or other media opacity (e.g., cataract). For these cases, B-scan ultrasonography is necessary to identify retinal detachments. B-scan ultrasonography can help identify the location of a retinal tear in the absence of a retinal detachment, although tears are often subtle and easy to miss. In the setting of a spontaneous vitreous hemorrhage without retinal tear or detachment, the eye can be monitored with serial ultrasonography; if the eye develops a retinal detachment, intervention is imperative (▶ Fig. 12.3).
Fig. 12.3 B-scan ultrasonography for a dense vitreous hemorrhage without a view to the posterior pole. B-scan ultrasonography showed a total macula-off retinal detachment, with a corresponding A-scan cross vector overlay showing a spike of high reflectivity corresponding to the retinal detachment.