To date, there is no known effective treatment for the non-proliferative form of macular telangiectasia type 2.

Treatment options are limited. No treatment has to date been shown to prevent progression. The variable course of progression of the disease makes it difficult to assess the efficacy of treatments. Retinal laser photocoagulation is not helpful. In fact, laser therapy may actually enhance vessel ectasia and promote intraretinal fibrosis in these individuals. It is hoped that a better understanding of the pathogenesis of the disease may lead to better treatments.

The use of vascular endothelial growth factor (VEGF) inhibitors, which have proven so successful in treating age-related macular degeneration, have not proven to be effective in non-proliferative MacTel type 2. Ranibizumab reduces the vascular leak seen on angiography, although microperimetry suggests that neural atrophy may still proceed in treated eyes.In proliferative stages (neovascularisation), treatment with Anti-VEGF can be helpful.

CNTF is believed to have neuroprotective properties and could thus be able to slow down the progression of MacTel type 2. It has been shown to be safe to use in MacTel patients in a phase 1 safety trial.

The most crucial aspect of managing patients with macular telangiectasia is recognition of the clinical signs. This condition is relatively uncommon: hence, many practitioners may not be familiar with or experienced in diagnosing the disorder. MacTel must be part of the differential in any case of idiopathic paramacular hemorrhage, vasculopathy, macular edema or focal pigment hypertrophy, especially in those patients without a history of retinopathy or contributory systemic disease.

Treatment options for macular telangiectasia type 1 include laser photocoagulation, intra-vitreal injections of steroids, or anti-vascular endothelial growth factor (anti-VEGF) agents. Photocoagulation was recommended by Gass and remains to date the mainstay of treatment. It seems to be successful in causing resolution of exudation and VA improvement or stabilization in selected patients. Photocoagulation should be used sparingly to reduce the chance of producing a symptomatic paracentral scotoma and metamorphopsia. Small burns (100–200 μm) of moderate intensity in a grid-pattern and on multiple occasions, if necessary, are recommended. It is unnecessary to destroy every dilated capillary, and, particularly during the initial session of photocoagulation, those on the edge of the capillary-free zone should be avoided.

Intravitreal injections of triamcinolone acetonide (IVTA) which have proved to be beneficial in the treatment of macular edema by their anti-inflammatory effect, their downregulation of VEGF production, and stabilization of the blood retinal barrier were reported anecdotally in the management of macular telangiectasia type 1. In two case reports, IVTA of 4 mg allowed a transitory reduction of retinal edema, with variable or no increase in VA. As expected with all IVTA injections, the edema recurred within 3–6 months, and no permanent improvement could be shown.14,15 In general, the effect of IVTA is short-lived and complications, mainly increased intraocular pressure and cataract, limit its use.

Indocyanine green angiography-guided laser photocoagulation directed at the leaky microaneurysms and vessels combined with sub-Tenon’s capsule injection of triamcinolone acetonide has also been reported in a limited number of patients with macular telangiectasia type 1 with improvement or stabilization of vision after a mean follow-up of 10 months.16 Further studies are needed to assess the efficacy of this treatment modality.

Recently, intravitreal injections of anti-VEGF agents, namely bevacizumab, a humanized monoclonal antibody targeted against pro-angiogenic, circulatory VEGF, and ranibizumab, a FDA-approved monoclonal antibody fragment that targets all VEGF-A isoforms, have shown improved visual outcome and reduced leakage in macular edema form diabetes and retinal venous occlusions. In one reported patient with macular telangiectasia type 1, a single intravitreal bevacizumab injection resulted in a marked increase in VA from 20/50 to 20/20, with significant and sustained decrease in both leakage on FA and cystoid macular edema on OCT up to 12 months. It is likely that patients with macular telangiectasia type 1 with pronounced macular edema from leaky telangiectasis may benefit functionally and morphologically from intravitreal anti-VEGF injections, but this warrants further studies.

Today, laser photocoagulation remains mostly effective, but the optimal treatment of macular telangiectasia type 1 is questioned, and larger series comparing different treatment modalities seem warranted. The rarity of the disease however, makes it difficult to assess in a controlled randomized manner.

However, these treatment modalities should be considered only in cases of marked and rapid vision loss secondary to macular edema or CNV. Otherwise, a conservative approach is recommended, since many of these patients will stabilize without intervention.

Supplements that include lutein and zeaxanthin may slow down the worsening of AMD. They have, however, not been shown to prevent the disease. There is not enough evidence to determine if statins have a role in preventing or slowing the progression of AMD. Antiangiogenic steroids such as anecortave acetate and triamcinolone acetonide have shown no evidence in preventing visual loss in people with neovascular AMD.

No medical or surgical treatment is available for this condition.

Laser treatment of drusen has been studied. While it is possible to eliminate drusen with this treatment strategy, it has been shown that this fails to reduce the risk of developing the choroidal neovascularisation which causes the blindness associated with age-related macular degeneration.

In 2005, steroids were investigated for the treatment of macular edema due to retinal blood vessel blockage such as CRVO and BRVO.

Macular edema sometimes occurs for a few days or weeks after cataract surgery, but most such cases can be successfully treated with NSAID or cortisone eye drops. Prophylactic use of Nonsteroidal anti-inflammatory drugs has been reported to reduce the risk of macular edema to some extent.

In 2010 the US FDA approved the use of Lucentis intravitreal injections for macular edema.

Iluvien, a sustained release intravitreal implant developed by Alimera Sciences, has been approved in Austria, Portugal and the U.K. for the treatment of vision impairment associated with chronic diabetic macular edema (DME) considered insufficiently responsive to available therapies. Additional EU country approvals are anticipated.

In 2013 Lucentis by intravitreal injection was approved by the National Institute for Health and Care Excellence in the UK for the treatment of macular edema caused by diabetes and/or retinal vein occlusion.

On July 29, 2014, Eylea (aflibercept), an intravitreal injection produced by Regeneron Pharmaceuticals Inc., was approved to treat DME in the United States.

Treatment requires careful consideration of angiographic findings when a choroidal neovascular membrane is suspected which is a condition that responds to treatment. A vitreo-retinal specialist (an ophthalmologist specialized in treatment of retinal diseases) should be consulted for proper management of the case.

Presumed ocular histoplasmosis syndrome and age-related macular degeneration (AMD) have been successfully treated with laser, anti-vascular endothelial growth factors and photodynamic therapy. Ophthalmologists are using anti-vascular endothelial growth factors to treat AMD and similar conditions since research indicates that vascular endothelial growth factor (VEGF) is one of the causes for the growth of the abnormal vessels that cause these conditions.

Treatment is based

on the stage of the disease. Stage 1 does not

require treatment and

should be observed. 4

Neovascularization

(stage 2) responds well

to laser ablation or

cryotherapy.2,4 Eyes

with retinal detachments (stages

3 through 5) require surgery, with

earlier stages requiring scleral

buckles and later stages ultimately

needing vitrectomy. 2,4

More recently, the efficacy of

anti-VEGF intravitreal injections

has been studied. In one study,

these injections, as an in adjunct

with laser, helped early stages

achieve stabilization, but further

investigation is needed.6

CNV is conventionally treated with intravitreal injections of angiogenesis inhibitors (also known as "anti-VEGF" drugs) to control neovascularization and reduce the area of fluid below the retinal pigment epithelium. Angiogenesis inhibitors include pegaptanib, ranibizumab and bevacizumab (known by a variety of trade names, such as Macugen, Avastin or Lucentis). These inhibitors slow or stop the formation of new blood vessels (angiogenesis), typically by binding to or deactivating the transmission of vascular endothelial growth factor ('VEGF'), a signal protein produced by cells to stimulate formation of new blood vessels. The effectiveness of angiogenesis inhibitors has been shown to significantly improve visual prognosis with CNV, the recurrence rate for these neovascular areas remains high.

CNV may also be treated with photodynamic therapy coupled with a photosensitive drug such as verteporfin (Visudyne). The drug is given intravenously. It is then activated in the eye by a laser light. The drug destroys the new blood vessels, and prevents any new vessels forming by forming thrombi.

Patients with optic disc drusen should be monitored periodically for ophthalmoscopy, Snellen acuity, contrast sensitivity, color vision, intraocular pressure and threshold visual fields. For those with visual field defects optical coherence tomography has been recommended for follow up of nerve fiber layer thickness. Associated conditions such as angioid streaks and retinitis pigmentosa should be screened for. Both the severity of optic disc drusen and the degree of intraocular pressure elevation have been associated with visual field loss. There is no widely accepted treatment for ODD, although some clinicians will prescribe eye drops designed to decrease the intra-ocular pressure and theoretically relieve mechanical stress on fibers of the optic disc. Rarely choroidal neovascular membranes may develop adjacent to the optic disc threatening bleeding and retinal scarring. Laser treatment or photodynamic therapy or other evolving therapies may prevent this complication.

Currently, there is no treatment for the disease. However, ophthalmologists recommend wearing sunglasses and hats outdoors and blue-light blocking glasses when exposed to artificial light sources, such as screens and lights. Tobacco smoke and second-hand smoke should be avoided. Animal studies also show that high doses of vitamin A can be detrimental by building up more lipofuscin toxin. Dietary non-supplemental vitamin A intake may not further the disease progression.

Clinical trials are being conducted with promising early results. The trials may one day lead to treatments that might halt, and possibly even reverse, the effects of Stargardt disease using stem cell therapy, gene therapy, or pharmacotherapy.

The Argus retinal prosthesis, an electronic retinal implant, was successfully fitted to a 67-year-old woman in Italy at the Careggi Hospital in 2016. The patient had a very advanced stage of Stargardt’s disease, and a total absence of peripheral and central visual fields.

STGD1 is the most common form of inherited juvenile macular degeneration with a prevalence of approximately 1 in 10,000 births.

Retinoschisis involving the central part of the retina secondary to an optic disc pit was erroneously considered to be a serous retinal detachment until correctly described by Lincoff as retinoschisis. Significant visual loss may occur and following a period of observation for spontaneous resolution, treatment with temporal peripapillary laser photocoagulation followed by vitrectomy and gas injection followed by face-down positioning is very effective in treating this condition.

It is important to distinguish between treatment of the underlying inflammation (PIC) and the treatment of CNV.

2-pronged approach:

Treatment is not always necessary and observation may be appropriate for lesions if they are found in non-sight threatening areas (that is not centrally).

Active lesions of PIC can be treated with corticosteroids taken systemically (tablets) or regionally by injections around the eye (periorbital). It has been argued that treating lesions in this way may help minimise the development of CNV.

The treatment of CNV:

Early treatment is required for this complication. There are several possible treatment methods, but none of these treatments appears to be singly effective for the treatment of CNV.

1. Corticosteroids: systemic or intraocular

2. ‘Second line’ immunosuppressants: There is evidence that combined therapies of steroids and second line immunosuppressants may be important.

3. Surgical excision of the affected area in well selected cases.

4. Intravitreal anti-VEGF agents. Examples are bevacizumab (avastin) and ranibizumab. These relatively new drugs are injected into the eye.

5. Photodynamic therapy (PDT): A photosensitive drug is ‘activated’ by strong light. Consideration may be given to combined therapy of PDT and anti VEGF.

6. Laser photocoagulation: This is occasionally used unless the CNV is subfoveal (affecting the central or macular part of the vision). The laser treatment can damage the vision.

The use of the intravitreal anti VEGF agents namely bevacizumab and ranibizumab have been described recently. The current evidence supporting the use of anti-VEGF agents is based on retrospective case studies and could not be described as strong. However, further data from prospective controlled trials are needed before the therapeutic role of anti-VEGF therapy in the uveitis treatment regimen can be fully determined. The anti VEGF agents furthermore have not been shown to have an anti-inflammatory effect.

Thus, treatment of the underlying inflammatory disease should play a central role in the management of uveitic CNV. A two-pronged treatment that focuses on achieving control of inflammation through the use of corticosteroids and/or immunosuppressive agents, while treating

complications that arise despite adequate disease control with intravitreal anti-VEGF agents, may be useful.

Regular monitoring is essential to achieve a good outcome. This is because even if there is no active inflammation, there may still be occult CNV which requires treatment to avoid suffering vision loss.

The incidence and prevalence of PMD are unknown, and no studies have yet investigated its prevalence or incidence. However, it is generally agreed that PMD is a very rare condition. Some uncertainty regarding the incidence of PMD may be attributed to its confusion with keratoconus. PMD is not linked to race or age, although most cases present early in life, between 20 and 40 years of age. While PMD is usually considered to affect men and women equally, some studies suggest that it may affect men more frequently.

Several diseases have been observed in patients with PMD. However, no causal relationships have been established between any of the associated diseases and the pathogenesis of PMD. Such diseases include: chronic open-angle glaucoma, retinitis pigmentosa, retinal lattice degeneration, scleroderma, kerato-conjunctivitis, eczema, and hyperthyroidism.

This ocular pathology was first described by Iwanoff in 1865, and it has been shown to occur in about 7% of the population. It can occur more frequently in the older population with postmortem studies showing it in 2% of those aged 50 years and 20% in those aged 75 years.

Usually being asymptomatic, drusen are typically found during routine eye exams where the pupils have been dilated.

Though there is no treatment for Cone dystrophy, certain supplements may help in delaying the progression of the disease.

The beta-carotenoids, lutein and zeaxanthin, have been evidenced to reduce the risk of developing age related macular degeneration (AMD), and may therefore provide similar benefits to Cone dystrophy sufferers.

Consuming omega-3 fatty acids (docosahexaenoic acid and eicosapentaenoic acid) has been correlated with a reduced progression of early AMD, and in conjunction with low glycemic index foods, with reduced progression of advanced AMD, and may therefore delay the progression of cone dystrophy.

There is no good evidence for any preventive actions, since it appears this is a natural response to aging changes in the vitreous. Posterior vitreous detachment (PVD) has been estimated to occur in over 75 per cent of the population over age 65, that PVD is essentially a harmless condition (although with some disturbing symptoms), and that it does not normally threaten sight. However, since epiretinal membrane appears to be a protective response to PVD, where inflammation, exudative fluid, and scar tissue is formed, it is possible that NSAIDs may reduce the inflammation response. Usually there are flashing light experiences and the emergence of floaters in the eye that herald changes in the vitreous before the epiretinal membrane forms g

Optic pits themselves do not need to be treated. However, patients should follow up with their eye care professional annually or even sooner if the patient notices any visual loss whatsoever. Treatment of PVD or serous retinal detachment will be necessary if either develops in a patient with an optic pit.

Several options exist for the treatment of BRVO. These treatments aim for the two of the most significant complications of BRVO, namely macular edema and neovascularization.

- Systemic treatment with oral Aspirin, subcutaneous Heparin, or intravenous thrombolysis have not been shown to be effective treatments for CRVO and for BRVO no reliable clinical trial has been published.

- Laser treatment of the macular area to reduce macular edema is indicated in patients who have 20/40 or worse vision and did not spontaneously improve for at least 3 months (to permit the maximum spontaneous resolution) after the development of the vein occlusion. It is typically administered with the argon laser and is focused on edematous retina within the arcades drained by the obstructed vein and avoiding the foveal avascular zone. Leaking microvascular abnormalities may be treated directly, but prominent collateral vessels should be avoided.

- The second indication of laser treatment is in case of neovascularization. Retinal photocoagulation is applied to the involved retina to cover the entire involved segment, extending from the arcade out to the periphery. Ischemia alone is not an indication for treatment provided that follow-up could be maintained.

- Preservative-free, nondispersive Triamcinolone acetonide in 1 or 4 mg dosage may be injected into the vitreous to treat macular edema but has complications including elevated intraocular pressure and development of cataract. Triamcinolone injection is shown to have similar effect on visual acuity when compared with standard care (Laser therapy), However, the rates of elevated intraocular pressure and cataract formation is much higher with the triamcinolone injection, especially the higher dosage. Intravitreal injection of Dexamethasone implant (Ozurdex; 700,350 μg) is being studied, its effect may last for 180 days. The injection may be repeated however with less pronounced effect. Although the implant was designed to cause less complications, pressure rise and cataract formation is noted with this treatment too.

- Anti-VEGF drugs such as Bevacizumab (Avastin; 1.25 -2.5 mg in 0.05ml) and Ranibizumab (lucentis) injections are being used and investigated. Intravitreal anti-VEGFs have a low incidence of adverse side effects compared with intravitreal corticosteroids, but are currently short acting requiring frequent injections. Anti-VEGF injection may be used for macular edema or neovascularization. The mechanism of action and duration of anti-VEGF effect on macular edema is currently unknown. The intraocular levels of VEGF are increased in eyes with macular edema secondary to BRVO and the elevated VEGF levels are correlated to the degree and severity of the areas of capillary nonperfusion and macular edema.

- Surgery is employed occasionally for longstanding vitreous hemorrhage and other serious complications such as epiretinal membrane and retinal detachment.

- Arteriovenous sheathotomy has been reported in small, uncontrolled series of patients with BRVO. BRVO typically occurs at arteriovenous crossings, where the artery and vein share a common adventitial sheath. In arteriovenous sheathotomy an incision is made in the adventitial sheath adjacent to the arteriovenous crossing and is extended along the membrane that holds the blood vessels in position to the point where they cross, the overlying artery is then separated from the vein.

Corneal transplant surgery may be difficult due to the peripheral thinning of the cornea, even with large and off-center grafts. Therefore, surgery is usually reserved for patients that do not tolerate contact lenses. Several different surgical approaches may be taken, and no one approach is currently established as the standard. Examples of surgical procedures used for PMD include: wedge resection, lamellar crescentic resection, penetrating keratoplasty, lamellar keratoplasty, epikeratoplasty and intracorneal segments. Transplantation of the entire thickness of the cornea (penetrating keratoplasty) may be performed if there is enough normal tissue present. However, if there is not enough normal tissue present, then attaching the graft is difficult.

Due to the thinning of the cornea, PMD patients are poor candidates for procedures such as LASIK and photorefractive keratectomy.

The visual prognosis of eyes with PIC that do not develop subfoveal CNV is good. If CNV is picked up early and treated appropriately then the visual outcome can also be good. Frequent monitoring is important to ensure a good outcome. Poor vision occurs mostly with subfoveal CNV or if subretinal fibrosis (scarring) has formed.

The above information comes from a Fact sheet produced by the Uveitis Information Group May 2011. It has been factually checked by a member of the charity's Professional Medical Panel.

Gene therapy is currently not a treatment option, however human clinical trials for both choroideremia and Leber's congenital amaurosis (LCA) have produced somewhat promising results.

Clinical trials of gene therapy for patients with LCA began in 2008 at three different sites. In general, these studies found the therapy to be safe, somewhat effective, and promising as a future treatment for similar retinal diseases.

In 2011, the first gene therapy treatment for choroideremia was administered. The surgery was performed by Robert MacLaren, Professor of Ophthalmology at the University of Oxford and leader of the Clinical Ophthalmology Research Group at the Nuffield Laboratory of Ophthalmology (NLO).

In the study, 2 doses of the AAV.REP1 vector were injected subretinally in 12 patients with choroideremia.

There study had 2 objectives:

- to assess the safety and tolerability of the AAV.REP1 vector

- to observe the therapeutic benefit, or slowing of the retinal degeneration, of the gene therapy during the study and at a 24-month post-treatment time point

Despite retinal detachment caused by the injection, the study observed initial improved rod and cone function, warranting further study.

In 2016, researchers were optimistic that the positive results of 32 choroideremia patients treated over four and a half years with gene therapy in four countries could be long-lasting.