Medical Care
This condition usually is treated by or with an internist/hematologist.
Surgical Care
Since vitreous hemorrhage and retinal detachment account for most visual loss in hemoglobinopathies, the primary goal in treating proliferative sickle retinopathy is to minimize or eliminate neovascularization. Although treatments are not indicated or required for stages I and II, most advocate the treatment of sickle retinopathy for stage III.
The most widely used therapeutic modalities include laser retinal photocoagulation, retinal cryotherapy, and vitrectomy/membranectomy. [24, 20, 25, 26] The most effective therapeutic modality with minimal postoperative complications appears to be scatter laser retinal photocoagulation.
Laser photocoagulation
Laser retinal photocoagulation is the more commonly practiced therapeutic modality.
Although relatively safe, laser photocoagulation complications include preretinal hemorrhage, vitreous hemorrhage, retinal breaks, retinal detachment, and choroidal neovascularization.
Different techniques have been advocated in treating proliferative sickle retinopathy, including scatter photocoagulation and feeder vessel photocoagulation. [27]
Scatter photocoagulation
Scatter photocoagulation appears to be the most efficacious (and therefore the preferred) treatment of sea fan lesions. [28]
The desired photocoagulation endpoint is regression of extraretinal fibroneovascular tissue.
Localized scatter photocoagulation is effective in treating early proliferative changes, especially neovascular lesions that lie flat against the retina. Once neovascularization invades the vitreous, localized scatter photocoagulation appears to be less effective.
Circumferential scatter photocoagulation places laser burns over a retinal zone of one of the following: at least 3 disc diameter areas of the nonperfused retina, as outlined by fluorescein angiography, or the entire avascular retina, as determined by fluorescein angiography or estimated by the distribution of the occluded vessel.
Unlike feeder vessel coagulation, scatter photocoagulation is easier to perform, more effective, and safer. This technique reduces the incidence of vitreous hemorrhage.
However, in cases where scatter photocoagulation alone does not achieve the desired result (ie, regression of proliferative changes), feeder vessel photocoagulation may be used as an adjunct to induce infarction to the remaining sea fans.
Follow-up care is usually within 1 week after laser surgery to rule out retinal detachment from contracture of the neovascular membrane after laser treatment.
After the first follow-up visit, monthly follow-up visits are advocated to confirm and monitor the regression of the neovascularization.
Insufficient treatment indicated by failure or arrest of the regression of the neovascularization requires further laser treatments at the time of follow-up care.
New or recurrent neovascularization in the treated eye is treated in the similar manner. [29, 30]
Feeder vessel photocoagulation
Obliterating feeder vessels by retinal photocoagulation has been used to cause infarction of peripheral neovascular beds.
This technique has been shown to manage proliferative sickle retinopathy effectively, especially in cases where neovascularization has persisted after extensive scatter photocoagulation treatment.
Feeder vessel photocoagulation frequently is complicated by the following: vitreous hemorrhage, retinal detachments, choroidal ischemia, choroidal neovascularization, subretinal hemorrhage and/or fibrosis, or macular pucker and hole formation.
To reduce complications, the feeder vessel technique has been modified into two sessions, permitting reduction in laser power. On initial treatment, laser burns are low intensity; upon follow-up, a second set of low-intensity burns are superimposed on the initial ones.
The method has been proposed to decrease the incidence of the Bruch membrane penetration, thereby decreasing the chance for choroidal neovascularization.
Scatter photocoagulation is the preferred technique.
Feeder vessel photocoagulation seldom is used because of its high complication rate. When used, feeder vessel photocoagulation is usually an adjunct to scatter photocoagulation.
Regular follow-up care is needed to detect and treat complications and new neovascularization. [31]
Retinal cryotherapy
In 1982, Hanscom demonstrated that retinal cryotherapy is useful in treating peripheral retinal ischemia as opposed to directly obliterating these neovascular beds. [32] This methodology of "indirect" obliteration of the neovascular bed showed complete regression of abnormal vessels with minimal complications.
Cryotherapy often is limited to cases with cloudy ocular media.
Single freeze-thaw and triple freeze-thaw have been advocated in treating PSR. However, it appears that triple freeze-thaw is associated with a high rate of complications (eg, proliferative vitreoretinopathy [PVR]) and, therefore, is not recommended.
Vitrectomy
Indicated in cases of nonresolving vitreous hemorrhage and retinal detachment (stages IV and V). [24, 20, 25, 26]
One of the more serious complications that is associated with vitreoretinal surgery is anterior segment ischemia. Other complications include sickling crisis, optic nerve, and macula infarctions.
This procedure relieves the internal tractional forces that act on the retina and facilitate retinal photocoagulation.
Rhegmatogenous retinal detachment in sickle cell disease usually is secondary to tractional membrane. Usually requiring pars plana vitrectomy, it seldom is treated with scleral buckling alone.
The following measures can decrease complications (ie, anterior segment ischemia):
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Preoperative partial exchange transfusions (rarely required) increase the amount of normal hemoglobin Hb A, thereby increasing the O2 -carrying capacity
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Administer local anesthesia, stellate ganglion block, and papaverine administration
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Provide cycloplegics (parasympathomimetics only)
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Decrease IOP
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Provide supplemental oxygen therapy
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IOP should be kept lower than 25 mm Hg preoperatively, intraoperatively, and postoperatively
Consultations
The following specialists may be consulted:
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Retina specialist
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Internist/hematologist
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Geneticist
Further Outpatient Care
Monitor medication dose and adverse effects.
Enroll patient in local sickle cell clinic.
Ophthalmologic follow-up care is determined by the proliferative stage.
Stages I and II: Follow-up care is performed every 6 months to 12 months.
Stages III and IV: Follow-up care is usually within 1 week after laser surgery to rule out retinal detachment. After the first follow-up visit, monthly follow-up visits are advocated to confirm and monitor the regression of the neovascularization. Insufficient treatment requires further laser treatments at the time of follow-up care.
Stage V: Follow-up care is based on retinal specialist consultation.
Further Inpatient Care
Inpatient care often is not needed, except for nonadherent patients in sickle cell crisis or for patients with a hyphema who are unable to comply with follow-up visits.
