Exudative retinal detachment: Description, Causes and Risk Factors:
The retina is responsible for creating the images that we see. Its neurosensory tissue lines the back of the eye and functions very similar to film in a camera. Ninety-five percent of the retina, called the peripheral retina, is responsible for side vision. The other five percent is the very center of the retina, called the macula. It is responsible for detailed vision for daily functions like reading and recognizing faces.
Anytime subretinal fluid accumulates in the space between the neurosensory retina and the underlying retinal pigment epithelium (RPE), a retinal detachment occurs. Depending on the mechanism of subretinal fluid accumulation, retinal detachments traditionally have been classified into rhegmatogenous, tractional, and exudative.
Under normal conditions, water flows from the vitreous cavity to the choroid (a highly vascular membrane in the eye between the retina and the sclera; a dark pigmentation minimizes the scattering of light inside the eye). The direction of flow is influenced by the relative hyperosmolarity of the choroid with respect to the vitreous and the RPE that actively pumps ions and water from the vitreous into the choroid. When there is an increase in the inflow of fluid or a decrease in the outflow of fluid from the vitreous cavity that overwhelms the normal compensatory mechanisms, fluid accumulates in the subretinal space leading to an exudative retinal detachment.
The composition of the choroidal interstitial fluid plays a fundamental role in the pathogenesis of an exudative retinal detachment. The composition of the choroidal interstitial fluid in turn is influenced by the degree of choroidal vascular permeability. Any pathological process that affects choroidal vascular permeability can potentially cause an exudative retinal detachment. Alternatively, damage to the RPE prevents the pumping action of fluid and can lead to fluid accumulation in the subretinal space. Several inflammatory, infectious, vascular, degenerative, malignant, or genetically determined pathological conditions have been recognized to cause exudative retinal detachments.
In preeclampsia, there is intense vasoconstriction of the choroidal arterioles, which leads to choroidal ischemia and RPE infarction. The outer blood-retinal barrier is broken down and causes increased vascular permeability.
: ERD is a rare complication of retinal vein occlusion (RVO), which characteristically develops in ischaemic cases. Resarchers described localized exudative that detachments following branch retinal vein occlusion in eight patients. There was complete resolution of the subretinal exudation in all six eyes treated in the quadrant of detachment with photocoagulation. Researchers reported exudative retinal detachment following central or hemicentral retinal vein occlusion in five patients. Neovascular glaucoma developed in two cases. The subretinal fluid absorbed completely or partially in the four eyes that were treated by panretinal photocoagulation (PRP); however, the final visual acuity (VA) was poor in all cases. Although the two patients described in the study were young, review of the previously described cases shows a mean age of 56.4 years, range 18-78 years. Furthermore, there is no sexual or racial predilection.
Both patients presented here suffered ischemic CRVO. In Case 1, the CRVO was ischaemic from onset and exudative retinal detachment developed within 3 months from diagnosis, whereas in Case 2 the CRVO progressed from nonischemic to ischemic over 7 weeks and the exudative retinal detachment developed 8 months following diagnosis. Angiography showed marked capillary nonperfusion, secondary telangiectasis, and late staining of the large retinal veins, which are characteristic of ischaemic retinal vein occlusion. The retinal telangiectasis is secondary to prolonged or permanent damage to retinal capillary endothelium and simulates congenital retinal telangiectasis.
Oral steroids have occasionally been used with variable results in young, otherwise healthy, patients who present with mild-to-moderate degrees of CRVO. In these patients, the term 'papillophlebitis' has been used by some authors. The typical presentation is that of normal or slightly reduced visual acuity, marked disc swelling, and retinal hemorrhages largely confined to the posterior fundus. It is thought that the venous obstruction is secondary to venous compression caused by disorders producing optic nerve and disc swelling, rather than a primary venous thrombosis occurring at the level of lamina cribrosa, as is usually the case in older patients. In our series, Case 2 was treated with a combination of panretinal photocoagulation and a short course of oral steroids. However, the visual acuity did not improve.
The pathogenesis of exudative retinal detachment following that vein occlusion appears multifactorial and includes vascular leakage from vascular damage, which in the two patients described here manifests not only by the marked volume of subretinal fluid but also by the presence of subretinal exudation, impaired retinal pigment epithelial and retinal capillary absorbing function, increased hydrostatic pressure, and absence of retinal venous collaterals. The mechanism of reattachment following photocoagulation may be owing to disruption of the retinal pigment epithelium (RPE) thus allowing absorption of subretinal fluid, ablation of viable but pathologic tissue, or obliteration of the leaking capillaries.
Our cases illustrate that exudative retinal detachment following CRVO is associated with severe visual loss. Although panretinal photocoagulation is effective in absorption of subretinal fluid and exudation and regression of rubeosis iridis, the visual prognosis remains poor.
: This was an interventional case series including six consecutive patients with malignant melanoma who experienced VA reduction secondary to associated exudative retinal detachment (ERD). Patients underwent complete ophthalmic evaluation and B-scan ultrasound. Treatment included proton-beam radiation or brachytherapy, prognostic transretinal tumour biopsy with 25-gauge vitrector and surgical treatment of exudative retinal detachment, including vitrectomy and drainage of subretinal fluid at the time of irradiation. Successful management of exudative retinal detachments associated with choroidal melanomas was observed in all cases, with significant restoration of vision. Steady regression of tumour thickness was noted clinically and ultrasonographically, without extrascleral extension or metastasis, and with no recurrence of exudative retinal detachment found over follow up. In the present study, the investigators have showed effective surgical treatment of exudative retinal detachment associated with malignant melanoma. These patients had significant restoration of vision, confirming that timely intervention of exudative retinal detachment associated with malignant melanoma can reverse visual loss in these patients. These findings are in contrast to previous reports of irreversible visual loss after exudative retinal detachments, and suggest that photoreceptor atrophy might play a role in visual loss associated with chronic exudative retinal detachments.
Patients may complain of a red eye.
Although the diagnosis of an ERD can usually be made clinically, the underlying etiology may be difficult to elucidate. Laboratory examinations under these circumstances are warranted.
Venereal Disease Research Laboratory (VDRL) test and fluorescein treponema antibody (FTA) test.
- Antineutrophil cytoplasmic antibodies
- Erythrocyte sedimentation rate (ESR).
- Rheumatoid factor (RF).
Ultrasound is a useful adjunct when the media is hazy. It can detect choroidal thickness, the presence or absence of choroidal masses, the size and location of choroidal masses, and scleral thickness. Peripheral annular choroidal detachments are seen in nanophthalmos and uveal effusion syndrome. Fluorescein angiography is a useful adjunct to identify areas of leakage in central serous chorioretinopathy, Vogt-Koyanagi-Harada syndrome, and Coats disease.
The medical and surgical treatments of ERD have to be tailored to the underlying condition. Inflammatory conditions, such as scleritis and Vogt-Koyanagi-Harada syndrome (VKH), should be treated with anti-inflammatory agents. Tumors need to be treated accordingly. External beam radiation therapy (EBRT) or brachytherapy with a plaque may be used for choroidal melanoma. Metastatic lesions respond to chemotherapy or localized radiation therapy. Choroidal hemangiomas may respond to laser photocoagulation or plaque brachytherapy. Retinoblastomas (Rb) may be shrunk with chemotherapy and then treated locally with heat, laser, or cryotherapy. Infectious etiologies may respond to antibiotics.
Reports exist of patients with ERD secondary to chronic renal failure that have spontaneous retinal reattachment following renal transplant or renal dialysis.
Surgical treatments of ERD have to be tailored to the underlying condition. Conditions with vascular anomalies, such as Coats disease, should be treated with laser, cryotherapy, or even vitrectomy to obliterate the vascular abnormalities. In nanophthalmos where the sclera is abnormally thick, vortex vein decompression with scleral windows and suprachoroidal fluid drainage is indicated. Congenital anomalies, such as optic pits or colobomas, may respond to vitrectomy and endolaser techniques. Central serous chorioretinopathy may respond to mild laser treatment of the focal areas that leak on fluorescein angiogram.
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