Retina Evaluation
Retinal detachment is a sight threatening condition with an incidence of approximately 1 in 10000.[2] [3] Before the 1920’s, this was a permanently blinding condition. In subsequent years, Jules Gonin, MD, pioneered the first repair of retinal detachments in Lausanne, Switzerland.[4] In 1945 after the development of the binocular indirect ophthalmoscope by Charles Schepens, MD, techniques for retinal detachment repair improved. In the last 50 years techniques in scleral buckling, pneumatic retinopexy and vitrectomy have made the repair of retinal detachments significantly more manageable with better visual outcomes.
Lattice degeneration is considered the most important peripheral retinal degeneration process that predisposes to a rhegmatogenous retinal detachment.[5] Other peripheral lesions having slight increased risk of retinal detachment include ora bays, meridional folds and complexes, and cystic retinal tufts.
Pathophysiology
Normally, the retinal pigment epithelium (RPE) is able to maintain adhesion with the overlying neurosensory retina through a variety of mechanisms. These mechanisms include active transport of subretinal fluid across RPE , metabolic activity of RPE, and interdigitation of the photoreceptor outer segments and the RPE microvilli. With retinal detachment, these mechanisms are overwhelmed leading to separation of the neurosensory retina from the retinal pigment epithelial layer.
Retinal detachment occurs when subretinal fluid accumulates between the neurosensory retina and the retinal pigment epithelium. This process can occur in three ways. One mechanism involves occurrence of a break in the retina allowing liquified vitreous to directly enter the subretinal space. This is known as a rhegmatogenous retinal detachment. Rhegmatogenous retinal detachments are often due to retinal tears associated with posterior vitreous detachment or trauma.
Although this monograph focuses on rhegmatogenous retinal detachment, it is pertinent to note the other major causes of retinal detachment. A second mechanism involves proliferative membranes on the surface of the retina or vitreous. These membranes can pull on the neurosensory retina causing a physical separation between the neurosensory retina and retinal pigment epithelium. This is called a tractional retinal detachment. Tractional retinal detachments can be seen in proliferative retinopathy due to diabetic disease, sickle cell and other disease processes leading to neovascularization of the retina. Tractional retinal detachments can also be due to proliferative vitreoretinopathy after trauma or surgery. The third mechanism for retinal detachment is due to accumulation of subretinal fluid due to inflammatory mediators or exudation of fluid from a mass lesion or insufficient RPE function. This mechanism is known as a serous or exudative retinal detachment. Serous detachments are caused by a number of inflammatory, or exudative retinal disease processes such as Sarcoidosis, medication toxicity, myeloma, or choroidal neoplasms. Serous retinal detachments may also be the presenting sign in patients with aggressive metastatic cancer, such as testicular cancer.[6]