Macrovessel

This large retinal macrovessel is an aberrant vein that courses through the fovea and across the horizontal raphe.

Courtesy of Dr. Rama Jager

Fluorescein angiography in a different patient reveals a large anomalous venous macrovessel and an abnormal associated capillary plexus. Visual acuity was reduced to 20/40.

Prepapillary Vascular Loop

This is an example of a congenital vascular loop that is usually unilateral in asymptomatic patients. Rarely the arteriolar loops can bleed into the vitreous or lead to a branch retinal vein or artery occlusion.

This 17-year-old otherwise healthy male presented with superior visual field loss in the right eye after sustaining head trauma. Examination revealed an inferior branch retinal artery occlusion (BRAO) (top) associated with a congenital vascular loop which had coiled, preventing distal blood flow (bottom image) .

Images courtesy of Ehsan Rahimy, MD

Familial Retinal Arterial Tortuosity

Congenital retinal tortuosity affects the arteries although tortuosity of the retinal veins may also be appreciated. These tortuous vessels are subject to occlusive and hemorrhagic complications.

These two patients have familial retinal arterial tortuosity with tortuosity of both the retinal arteries and veins. This disorder occurs bilaterally.

Ophthalmic Artery Occlusion

A patient with an ophthalmic artery occlusion typically presents with no light perception vision. A “cherry red” spot is not present in almost half of these cases because of choroidal insufficiency. Following reperfusion of the obstructed circulation, diffuse retinal pigment epithelium (RPE) abnormalities may develop.

This patient had an ophthalmic artery occlusion. In the acute stage, there is diffuse whitening in the posterior fundus but no “cherry red” spot (left upper) . Two months later, the outer retinal ischemia has largely subsided, leaving a reddish-brown discoloration in the foveal region. There is still some perifoveal whitening of the inner retina (right upper) . Following resolution of the acute whitening of the retina, the fundus has diffuse RPE changes, decreased retinal vascular caliber, and sheathing irregularities (lower left) . Note the compensatory vessels around the circumference of the optic nerve head (magnified inset), collaterals between the retinal and ciliary circulations, referred to as Nettleship collaterals.

These are two cases of old ophthalmic artery occlusion. There is widespread pigment epithelial atrophy and some granular pigmentation (left) . The optic nerve is pale, and the retinal vessels are narrow from the antecedent ischemia. Note the constricted blood vessels, the diffuse pigmentary changes, and the optic atrophy on the right.

Central Retinal Artery Occlusion

Central retinal artery obstructions are most commonly seen in older adults. These patients often have signs of cardiovascular disease. The most common cause is embolism from a carotid artery plaque. In the acute phase there is opacification of the superficial retina except for the fovea in which a “cherry red” spot is present. In some cases, there is segmentation or “boxcarring” of the retinal vasculature.

This patient has an acute central retinal artery occlusion with a cherry red spot. Note the plaque inferiorly (arrow) . Fluorescein angiogram in this case reveals macular ischemia.

The histopathology shows a recent central retinal artery occlusion with a fresh intravascular thrombus and edema of the inner retinal layers.

This patient has an acute central retinal artery occlusion with whitening of the retina and a “cherry red” spot. There is severe non-perfusion of the retina with “boxcarring” on the fluorescein angiogram (FA) (arrows) .

Courtesy of Dr. Pawan Bhatnagar

This patient has a central retinal artery occlusion with a “cherry red” spot and retinal whitening. There is very minimal sparing of the temporal peripapillary retina from perfused ciliary vessels (arrow) .

This patient presented with a central retinal artery occlusion with diffuse whitening of the inner retina and a cherry red spot. Note the presence of peripapillary whitening representing axoplasmic stasis. Three weeks later (right) most of the whitening has resolved with some persistence in the superior macula (arrows) . The optic nerve has become pale and the vision was unimproved. The carotid angiogram (left) shows obstruction of the carotid system (arrow).

Courtesy of Dr. Robert Mittra

This patient had an old central retinal artery occlusion. There is resultant optic atrophy and peripapillary sheathing of the arteriolar vasculature.

This patient presented with a partial central retinal artery occlusion with multiple CWS. There is boxcarring of the retinal vessels and residual emboli that have passed into the distal vasculature (arrows) . The optic nerve is pale.

Central Retinal Artery Occlusion with Sparing of the Ciliary Artery

These patients all presented with central retinal artery occlusion with sparing of the ciliary artery. Fluorescein angiography documented persistent perfusion of the ciliary artery, partially sparing the fovea (arrows) . Note the presence of retinal venous filling emanating from the ciliary circulation.

Images courtesy of Ophthalmic Imaging Systems, Inc

Branch Retinal Artery Occlusion

A branch retinal artery obstruction (BRAO) presents with superficial retinal whitening in a geographic distribution of the obstructed arteriole. As is the case for central retinal artery occlusions, most patients have pre-existing cardiovascular disease. The most common cause is embolism from the carotid artery. The absence of a visible intravascular plaque does not necessarily imply a non-embolic cause because plaques may distalize. The visual prognosis is relatively good, unless there is an underlying systemic factor that increases the risk for recurrence.

These are examples of acute branch retinal artery occlusions. Note the acute whitening of the inner retina that follows the course of the obstructed vessel. The extent of whitening is dependent on the size of the arteriole. In about one-third of cases, an embolus or plaque on the optic nerve may be identified (upper right) . This patient’s embolism originated from mitral valve prolapse. There is a cotton-wool spot from superficial capillary occlusion in the lower middle image (arrow) .

This is a patient with progressive branch retinal artery occlusion. The image on the left was obtained 2 days before the image on the right.

Multiple Branch Artery Occlusions

Note the multiple branch retinal artery occlusions in these two patients. The top images are of a patient who experienced embolic disease at the time of cardiac surgery. The bottom images are from a patient with multiple retinal vascular emboli from cardiovascular disease. Note the obstructed sites on the FA (arrows) . There is still good perfusion of the central macula.

Recurrent Retinal Artery Occlusions

This patient presented with a recurrent branch artery occlusion. An older superotemporal branch occlusion with sheathing and mineralization of the retinal arteriole is present and a more acute branch retinal artery occlusion of the nasal macula is also noted.

Embolus Distalization

This patient illustrates a retinal vascular embolus first seen at an early bifurcation of the arteriole (far left image) . Over the ensuing days, it migrated distally (arrows) through the posterior pole to the near peripheral fundus.

PAMM (Paracentral Acute Middle Maculopathy)

Paracentral acute middle maculopathy (PAMM) is a recently described entity with a characteristic band of hyper-reflectivity at the level of the inner nuclear layer on spectral domain optical coherence tomography (SD-OCT). Associated whitening on color fundus photography and hypo-reflectivity with near-infrared reflectance imaging may also be appreciated. Inner nuclear layer (INL) infarction due to ischemia of the deep retinal capillary plexus is the likely etiology. Many ocular and systemic conditions can be associated with PAMM including retinal vein occlusion, retinal artery occlusion, diabetic retinopathy, Purtscher retinopathy, and sickle-cell retinopathy.

PAMM versus CWS

Cotton-wool spot (CWS) is more superficial, chalk white in appearance, and associated with hyper reflectivity at the level of the ganglion cell and nerve fiber layers (with OCT) and due to ischemia or infarction of the superficial retinal capillary plexus.

This figure illustrates the difference between a CWS and a PAMM lesion. The images on the right are follow-up images illustrating resolution of the CWS and PAMM lesions. Note the brighter white, and more superficial appearance of the CWS (top left, green line) on the color fundus photo compared to the deeper, grayish appearance of the PAMM lesion (top left, yellow line). Red-free images also can highlight this difference with the CWS again appearing bright white compared to the deep gray appearance of the PAMM lesions (middle left). On FA, CWS show hypo-fluorescence, while PAMM lesions appear normal (bottom left).

On spectral domain optical coherence tomography (SD-OCT), PAMM lesions are characterized by hyper-reflectivity in the middle retinal layers in the acute phase (upper left) with subsequent thinning of those layers in the chronic phase (lower left). CWS are characterized by hyper-reflectivity and thickening of the NFL and ganglion cell layers in the acute phase (upper right) with subsequent thinning of those layers in the chronic phase (lower right).

PAMM Associated with BRAO

This patient has a small branch artery occlusion in the macula with a visible Hollenhorst plaque (top left, arrow) causing a deep gray-white infarct (top right) . The corresponding OCT demonstrates PAMM due to ischemia of the deep retinal capillary plexus and infarction of the inner nuclear layer.

Courtesy of Brandon Lujan, MD

This patient, described earlier in the “ Prepapillary Vascular Loop ” section, suffered a BRAO secondary to torsion of a prepapillary vascular loop (top) . SD-OCT through the macula reveals diffuse PAMM lesions secondary to ischemia of the deep retinal capillary plexus.

Image courtesy of Ehsan Rahimy, MD

Cilioretinal Artery Occlusion

Cilioretinal artery occlusions can occur in isolation or in association with giant cell arteritis and central retinal vein occlusion. They generally cause a sudden loss of central vision since these vessels perfuse the central macula. There is acute retinal whitening corresponding to the geographic distribution of the vessel. An FA may show obstruction or delayed perfusion, as in the case below.

This patient had an occlusion of the superior branch of the cilioretinal artery. Note the ischemic whitening on color fundus photography and the corresponding hypofluorescence with FA.

A cilioretinal artery occlusion is noted in this patient with corresponding ischemic whitening in the macula.

Plaques

About one-third of all retinal arteriolar occlusions are noted to be associated with plaques, some of which are glistening or mineralized. They are typically found at bifurcations, but not always. Retinal emboli originate from the carotid artery or the heart.

Note the multiple cases of branch retinal artery occlusion. Some are acute with ischemic whitening of the retina, whereas others have resolved. Rarely there is hemorrhage surrounding the plaque as noted in the lower right image. The carotid angiogram on the right shows multiple constrictions of the extracranial vessels perfusing the eye (arrows) .

Central Retinal Vein Occlusion

This patient has non-ischemic central venous occlusion with retinal venous tortuosity and few hemorrhages at the disc and in each quadrant of the mid periphery. The FA shows segmental staining of the venules (arrows) and minimal leakage at the optic nerve. There is no evidence of significant retinal capillary ischemia or non-perfusion.

Note these two cases of more severe non-ischemic central venous occlusion with more significant retinal hemorrhage. The retinal hemorrhages are more prominent in the superior hemisphere (right) .

Left montage courtesy of Dr. Matthew Benz

Note the non-ischemic CRVO in this young patient in his 30s, with no history of diabetes or systemic hypertension. There is disc edema, intraretinal hemorrhages and microaneurysms, and no evidence of significant retinal ischemia or non-perfusion with the FA.

Ultra widefield angiography of two cases of CRVO is shown. The top image shows patchy blockage from hemorrhage but intact peripheral perfusion. The lower image displays severe capillary non-perfusion.

This is a clinicopathologic correlation of an acute hemorrhagic central retinal vein occlusion within 24 hours. Light microscopy shows marked intraretinal hemorrhage and a fresh thrombus (arrowhead) in the central retinal vein at the posterior aspect of the lamina cribrosa.

These are two cases of ischemic central retinal vein occlusion. There is marked dilation and tortuosity of the retinal venous system, widespread retinal hemorrhages, and macular edema.

Wyburn–Mason Syndrome and Central Retinal Vein Occlusion

Note the presence of dilated tortuous retinal vessels and arteriolar-venular shunting in this case of Wyburn–Mason syndrome. The FA was taken 3 years prior to development of an acute hemorrhagic central retinal vein occlusion (right) . It is not uncommon for these congenital shunts to develop venous occlusive disease and secondary ischemia and neovascularization.

CRVO and Cilioretinal Artery Occlusion

These are examples of non-ischemic CRVO with associated cilioretinal artery occlusions.

Right image courtesy of West Coast Retina

This patient developed a central retinal vein occlusion with cilioretinal artery occlusion. Note the whitening of the inferior macula in the distribution of the cilioretinal artery (top left) and the delayed and incomplete filling of the cilioretinal artery on FA taken at 18 s post injection (top right). SD-OCT through the macula illustrates PAMM with hyper-reflective band-like lesions at the level of the inner nuclear layer due to ischemia of the deep retinal capillary plexus.

CRVO and PAMM

This 56-year-old female developed a central retinal vein occlusion with PAMM. Note the engorged venous system with intraretinal hemorrhages and deep gray lesions in the macula (top left). The gray lesions appear dark in a perivenular “fern-like” pattern on near infrared (top right) and correspond to hyper-reflective lesions at the level of the inner nuclear layer on SD-OCT (bottom).

Note the presence of PAMM (arrows) in the color and OCT images (left) in this patient with CRVO. The CME is much improved after intravitreal anti-vascular endothelial growth factor (anti-VEGF) therapy ( right, OCT).

Collateralization

These are four examples of optociliary collaterals that develop in cases of CRVO to bypass the occlusion of the central retinal vein. They are on the venous side of the circulation and do not leak on FA.

Carotid Cavernous Fistula and Central Retinal Vein Occlusion

This patient has a CRVO with intraretinal hemorrhages and tortuous vessels and dilated conjunctival vessels due to a carotid cavernous fistula that should be considered in the differential diagnosis of CRVO.

Courtesy of Robert Hammond

These are two additional cases of CRVO associated with carotid cavernous sinus fistula.

Natural Course

An acute central retinal vein occlusion with severe disc edema and intraretinal hemorrhages is shown (top) . There was spontaneous resolution of the obstruction with improvement of vision (bottom).

Treatment: Laser Photocoagulation

This patient presented with a central retinal vein occlusion with widespread peripheral capillary non-perfusion illustrated with ultra-widefield fluorescein angiography (left) . Widefield FA six month after the placement of panretinal photocoagulation (PRP) to ablate the ischemic retina is shown on the right.

Image courtesy of Richard Spaide

Treatment: Intravitreal Anti-VEGF Therapy

Four cases of CRVO complicated by CME are shown with spectral domain OCT prior to treatment (left images). One month after intravitreal anti-VEGF therapy CME is significantly improved in each case (right images).

An ischemic central retinal vein occlusion with macular edema is illustrated. On the left is the FA that shows macular ischemia (arrows) and patchy blockage from retinal hemorrhage. The top right OCT shows severe CME at baseline. One month after Ozurdex injection, there is resolution of the edema (second from top), with recurrence 5 months after the injection (third from top). The bottom OCT shows improvement one month after administration of second Ozurdex implant.

Branch Retinal Vein Occlusions

BRVO occurs most frequently in patients with a history of hypertension or diabetes. The occlusion occurs at the site of an arteriole–venous crossing, unless there is a focal inflammatory process in the wall of the vessel. BRVO may be complicated by vitreous hemorrhage, capillary non-perfusion, neovascularization of the disc or retina, fibrous proliferation with traction retinal detachment, and/or macular edema. Recanalization and reperfusion of the vein with compensatory retinal venous to venous collateralization is typical of the chronic phase of the disease. Retinal branch vein occlusions range from small tributary obstructions that become symptomatic when they include the macula to hemispheric occlusions that involve at least half of the fundus.

These are examples of patients with BRVO. The top row middle image shows a small macular BRVO that extends into the foveal area. The remaining cases are major BRVOs with quadrantic distribution of edema and hemorrhage.

This patient has chronic exudation in the macula with lipid precipitates secondary to hemispheric retinal vein occlusion.

Courtesy of Ophthalmic Imaging Systems, Inc

This is an example of hemispheric retinal vein occlusion. There is widespread capillary dropout in the inferior periphery (arrows) with extensive leakage and blockage by hemorrhage.

Image courtesy of Richard Spaide

An arteriolar-venous crossing abnormality is shown in this patient. It is characterized by prominence of the venule at its proximal segment, a small sentinel hemorrhage at the crossing, and obliteration of the venule at its common sheath with the crossing arteriole. This constellation of findings has been referred to as the pre-thrombotic sign of Bonnet, since some of these patients may progress to an acute BRVO. The FA shows a localized perfusion delay of the compressed retinal vein distal to the arteriolar-venular crossing.

This is a histopathology section of a retinal vein occlusion. The area of occlusion reveals a single channel of recanalization of the superotemporal vein as it crosses under the arteriosclerotic artery.

Note the presence of retinal neovascularization associated with BRVO in these three cases. The FA shows peripheral capillary non-perfusion and ischemia and neovascularization (arrow) .

Compensatory Collateralization

These are patients who have developed collateralization (venous–venous) to compensate for a retinal branch vein occlusion. The collaterals course across the horizontal raphe or bridge the obstructed site or connect to adjacent veins in the far periphery of the fundus. Collaterals do not leak with FA.

The above color and FA montage demonstrate a case of Wyburn–Mason syndrome with an arteriovenous shunt superonasal off the disc. Note the superotemporal BRVO with prominent collaterals across the temporal raphe.

Treatment: Laser Photocoagulation

Laser photocoagulation treatment can be used to focally ablate leaking microaneurysms within the zone of the branch vein occlusion (left) . Lipid was extending into the fovea and photocoagulation burns gradually induced resolution of the exudation. The patient on the right had chronic diffuse macular edema. A macular grid laser treatment was carried out that resulted in resolution of the central edema and improvement of vision.

Treatment: Intravitreal Pharmacotherapy

This patient developed a macular BRVO and was treated with intravitreal anti-VEGF therapy with resultant resolution.

This patient with dry age-related macular degeneration suffered a superior hemispheric retinal vein occlusion, which was treated with intravitreal anti-VEGF therapy. Color fundus montage before (top) and after (second row) therapy shows marked resolution of the intraretinal hemorrhages, revealing underlying macular drusen. SD-OCT taken at the time of presentation revealed macular edema as well as multiple drusen and a large central drusenoid pigment epithelial detachment (PED) (third row). With anti-VEGF therapy the intraretinal fluid greatly improved (bottom row).

Retinal Arteriolar Macroaneurysm

Retinal arteriolar macroaneurysm is an acquired fusiform or round dilatation that affects a retinal artery within its first three branches from the disc and that occurs typically in the posterior pole. These abnormalities are first observed in the fifth decade of life and are associated with surrounding exudative detachment of the retina, lipid deposition, and hemorrhage beneath, within, and above the retina. Macroaneurysms may be recurrent or multiple, along the course of the same vessel or seen elsewhere at another arteriole in the same eye.

These cases represent retinal arteriolar macroaneurysms. On the left, there is a bilobed aneurysm along the course of the involved arteriole, surrounded by dense circinate lipid exudation. The middle image shows exudative detachment with lipid deposition, which courses to the fovea. On the right is an FA showing aneurysmal staining of the arteriolar macroaneurysm.

Indocyanine green (ICG) angiography may enhance the detection of a macroaneurysm, particularly if it is partially covered by hemorrhage.

This patient demonstrates that macroaneurysms may be multiple and recurrent. An acute macroaneurysm is seen along the course of the superotemporal arteriole with concentric hemorrhage. An old macroaneurysm that was lasered is noted more distally. Note the atrophic scar and narrowing of the involved vessel (arrow) .

This patient has a bilobed double macroaneurysm along the same vessel with associated hemorrhage and exudation.

The histopathological specimen shows a thrombosed arteriolar macroaneurysm with retinal hemorrhage and cystic edema within the retina.

Retinal macroaneurysms may present with pre-retinal, intraretinal, or subretinal hemorrhage. It may form an hourglass configuration with more blood in front of and below than within the retina (left) . The bleeding may extend into the vitreous, where it can gravitate inferiorly (middle). As the hemorrhage from a macroaneurysm resolves, it becomes dehemoglobinized with a yellowish color (right) .

SD-OCT through this macroaneurysm at the superotemporal arcade (thick arrow) shows a markedly enlarged vessel contour with mild hemorrhage in the adjacent inner retina. The thin arrow denotes the normal superotemporal arcade vein.

Image courtesy of Anat Loewenstein and David Goldstein

This is a patient with a retinal arteriolar macroaneurysm, as seen on the FA on the left. Following treatment, there was recurrent bleeding (middle). A repeat FA showed regression of the initial lesion but a recurrent macroaneurysm is noted on the nasal side of the original one.

Note the superotemporal hemorrhage that is both pre-retinal and subretinal (“hourglass bleeding”). Central subretinal hemorrhage is also present. There is reactive vascular hyperplasia at the site of the superotemporal macroaneurysm, simulating an angiomatous proliferation that stains with fluorescein angiography. The lower left color image shows spontaneous resolution of the hemorrhage and the retinal arteriolar macroaneurysm, which now has a fibrous capsule. Note the associated large retinal venular macrovessel that extends superotemporally and then inferiorly across the horizontal raphe.

Treatment: Laser

This patient had significant central lipid deposition associated with an inferotemporal retinal arteriolar macroaneurysm. Following focal laser photocoagulation to the macroaneurysm, there was resolution of the exudation over a period of many months. The macroaneurysm regressed to a pigment epithelial hyperplastic scar.

Courtesy of Dr. Maurice Rabb

Treatment: Anti-VEGF Therapy

Intravitreal anti-VEGF therapy may be considered to decrease macular edema associated with retinal artery macroaneurysms. Note these three cases of macroaneurysm (top row) complicated by hemorrhage. The lower images show resolution of hemorrhage after intravitreal bevacizumab injection in each case that may reflect the natural history of this disorder.

Coats Disease and Macular Telangiectasia Type I (Congenital Telangiectasia, Leber Miliary Aneurysms)

Coats disease is a unilateral disorder with a very high predilection for males and characterized by retinal telangiectasia and lipid exudation. Exudation can be so severe as to cause leukocoria and exudative retinal detachment in young patients. Macular telangiectasia type 1 is a variant of Coats disease that affects male adults and consists of unilateral dilated and aneurysmal capillaries with associated ischemia and exudation typically limited to the central macular region.

This patient has Coats disease. Peripheral exudative detachment of the nasal retina is noted with lipid deposition at the posterior border. The dilated capillary net is seen posterior to the larger aneurysms. Peripheral to these vascular changes is a zone of ischemia, characteristic of the disorder.

This patient has Coats disease with dilated capillaries and “light bulb” aneurysms, venous macroaneurysms, and peripheral ischemia.

These three patients with Coats disease demonstrate typical manifestations. In the periphery, there are multiple macroaneurysms (left) . In the macular region (middle), chronic lipid deposition has resulted in a fibrous pigmented scar at the fovea. The image on the right shows macroaneurysms, which are evident in the periphery, but obscured by dense lipid deposition in the more posterior fundus (arrows) .

These two patients with Coats disease presented without visual dysfunction. On incidental examination, dilated telangiectatic vessels were noted that were associated with multiple aneurysmal lesions of various sizes. Vascular sheathing peripheral ischemia and a circinate pattern of exudate are present. Note the halo of fibrous proliferation around some of the larger aneurysms. Curiously, neither hemorrhage nor pre-retinal neovascularization is characteristic of this vasculopathy, although vasoproliferative tumors may complicate this disorder.

This patient has a zonal area of telangiectatic and aneurysmal lesions due to Coats disease and surrounded by circinate lipid deposition.

This patient has widespread Coats disease involving the central and peripheral fundus. Macroaneurysms (arrows) are seen with associated hemorrhage and widespread circinate lipid deposition. Vascular sheathing is also seen in this patient, which is not uncommon in this disorder. Peripapillary pigmentary scarring was from previous laser photocoagulation treatment.

This young patient presented with Coats disease that was incidentally diagnosed. Widespread lipid deposition from telangiectatic vascular abnormalities is evident in the peripheral fundus.

Ultra-widefield fluorescein angiography of this patient with Coats disease shows a normal right eye. The left eye has marked vascular tortuosity, macular edema and exudate. Peripheral capillary telangiectasia with non-perfusion and leakage are also present.

These patients demonstrate the spectrum of clinical findings seen in Coats disease. In the top row, a fringe of lipid deposition is encroaching on the posterior pole and is associated with peripheral telangiectasia. Ischemia, telangiectasia, aneurysmal formation, and leakage are present without pre-retinal hemorrhage or neovascularization, not an unusual finding in this disorder. There is aneurysmal formation on the bottom right image and even a sausage-like swelling of a venule (arrow) .

These are patients with macular telangiectasia type 1 or adult-onset Coats disease. The aneurysms can vary in size from small capillaries to macroaneurysms with associated lipid deposition, hemorrhage, ischemia, and leakage. A radial configuration of lipid can be seen, particularly in the central macular area, as shown on the lower middle image.

This patient with macular telangiectasia type 1 has prominent capillaries and microaneurysms seen on the early FA (middle) with late leakage (right) in the juxtafoveal region.

These adult male patients have macular telangiectasia type 1 or adult-onset Coats disease. Note that the unilateral microaneurysms can vary in size, distribution, and density.

This boy with Coats disease presented with dense subretinal and intraretinal exudation in the macula. Spectral-domain OCT demonstrates hyper-reflective exudates at the level of the outer plexiform layer (immediately beneath the deep retinal capillary plexus) and subretinal exudates temporally.

On the left is a histopathological image of macular telangiectasia type 1. Note the large, thin-walled retinal vessels, consisting of both capillaries and arterioles. There are a few endothelial cells and virtually no pericytes. On the right is a specimen from a patient with Coats disease. The subretinal space is filled with cholesterol crystals (asterisk) and pigment-laden macrophages (arrow) .

Treatment: Laser

This patient has severe macular lipid exudation secondary to Coats disease in the peripheral part of the fundus. Note the dense lipid in the central macula (second image) and the peripheral telangiectasia and aneurysms with associated exudation (first image) . Scatter laser treatment was applied to the periphery (third image). Following laser treatment, there was slow but progressive resolution of the lipid in the periphery and in the macula.

This patient had macular telangiectasia type 1 with a stellate configuration of circinate lipid deposition surrounding the telangiectatic lesions. A cluster of small microaneurysms were present and noted on the FA. Following focal laser photocoagulation, the exudates resolved with few atrophic scars.

This patient developed macular telangiectasia type 1 in adulthood. Radial lipid deposition is associated with microaneurysms. Following focal laser photocoagulation, the lipid gradually resolved over several months with few pigmented scars.

This young adult male presented with telangiectasia involving the macula and inferonasal periphery. The FAs show the aneurysmal lesions. Laser photocoagulation of these areas led to resolution of the exudation. The patient developed a new aneurysmal lesion in the inferior peripheral retina (arrow, middle color image). The lesion was also photocoagulated and the circinate lipid resolved.

This is a 13-year-old female with Coats disease. There is exudative detachment of the macula, a dependent bullous detachment of the inferior retina, and a focal area of hemorrhage and exudation temporally. The yellowish discoloration may partially represent degenerated blood. The FA shows ischemia and telangiectatic lesions with multiple aneurysms temporally. There is no leakage in the macula where the exudate had pooled in the subneurosensory space. The entire inferior detached retina showed evidence of leakage in areas of dilated capillaries.

Telangiectatic lesions were directly targeted and lasered in the same patient as above, resulting in the resolution of the inferior detachment but with an increase in macular exudate. Pre-retinal hemorrhage also occurred inferiorly and temporally due to pre-retinal neovascularization (arrow) . Additional laser photocoagulation was performed and regression of the neovascularization and resolution of the leakage was noted (middle row) . Gradually the lipid in the macular area cleared over a period of 6 months (lower left) and 3 years (lower right).

This adult male developed adult Coats disease (i.e., Lebers miliary aneurysms) with telangiectatic vascular disease present inferotemporal in the periphery. There was heavy, dense lipid exudation in the macula. Scatter laser was successful. The detachment resolved but the macula developed a fibrotic scar due to antecedent lipid deposition.

Treatment: Anti-VEGF Therapy

This case illustrates massive lipid exudation from a vasoproliferative mass (complicating Coats disease) in the superior retina associated with an inferior exudative detachment. Fluorescein angiography (top right) shows telangiectatic vessels, aneurysms, and leakage suggestive of Coats and associated with the vasoproliferative tumor. Following laser photocoagulation to the abnormal Coats vessels and after intravitreal bevacizumab injection, the leakage and detachment resolved (bottom).

This patient had diffuse lipid exudation throughout the fundus and involving the macula (left images) and associated with cystoid macular edema seen on spectral domain OCT (bottom left). After laser photocoagulation to the leaking vessels and after a single intravitreal bevacizumab injection, the exudates and CME resolved (right images) .

Macular Telangiectasia Type 2 (Idiopathic Perifoveal Telangiectasia, Idiopathic Juxtafoveal Telangiectasis Type 2)

Macular telangiectasia type 2 (Mactel type 2) has also been termed idiopathic perifoveal telangiectasia or idiopathic juxtafoveal telangiectasis type 2. It is a slowly progressive bilateral perifoveal disorder with vasculopathic and neurodegenerative features. Although the pathogenesis remains unknown, histologic evidence points to a degeneration of the Müller cells. The earliest findings include loss of the macular pigment, telangiectatic changes in the temporal fovea, and discontinuities in the ellipsoid zone. As the disease progresses, these findings spread circumferentially beyond the temporal fovea with increased leakage, formation of right-angle venules, and further disruption of the retinal architecture with formation of cavitations on OCT. In some instances, intraretinal crystalline deposits and pigmentary changes are present. The vascular changes initially arise in the deep retinal capillary plexus, but in advanced cases, subretinal neovascularization can ensue which can lead to disciform scarring.

Mactel type 2 has characteristic multimodal imaging findings. The color image shows subtle perifoveal graying. The FA shows dilated telangiectatic capillaries most predominant in the temporal fovea with late hyperfluorescence. The macular pigment is diffusely depleted as seen on dual wavelength autofluorescence. The spectral-domain OCT shows ellipsoid zone loss with an inner retinal cavitary cyst in the retina.

These short-wavelength autofluorescence images of patients with Mactel type 2 illustrate the depletion of macular pigment that unmasks the autofluorescence signal of the foveal region.

These images demonstrate the spectrum of disease severity in three separate cases of Mactel type 2. The top two rows show early and late FAs. The third row illustrates dual wavelength autofluorescence and the macular pigment density. The bottom row includes spectral domain OCTs through the fovea. The left column shows a case of early disease with only temporal vascular changes and loss of macular pigment. There is limited ellipsoid zone loss and mild intraretinal cavitation. The middle column is more advanced with both nasal and temporal involvement and more diffuse atrophic and cavitary changes on OCT. The right column is an advanced case with severe outer retinal atrophy but without evidence of subretinal neovascularization.

OCT angiography provides enhanced visualization of the abnormal retinal capillaries in Mactel type 2. The color image shows the classic perifoveal graying and crystal deposition. Note the temporal hyperfluorescent staining that blurs the vascular anatomy with fluorescein angiography. OCT angiography of the superficial retinal capillary plexus (middle left) in this case is unremarkable but shows a dilated microvascular network with segmentation through the deep capillary plexus (DCP; middle right and bottom left ). The color montage highlights the abnormal DCP vessels in yellow.

SD-OCT illustrates typical alterations seen in Mactel type 2 including outer retinal atrophy and cystic retinal cavitations. The bottom right image illustrates two aneurysmal dilations of vessels in the temporal perifovea (arrows) .

This is a postmortem clinicopathologic correlation of a patient with Mactel type 2. The color image shows macular pigment depletion and perifoveal pigmentary changes. After histologic processing of the retina, the sections were stained with a vimentin antibody that stains Müller cells. There is notable depletion of the Müller cells in the central affected area.

This is another postmortem clinicopathologic analysis showing abnormal vessels at the level of the deep capillary plexus.

This patient with Mactel type 2 has more advanced disease with vascular abnormalities encompassing the entire foveal area.

Pigment Hyperplasia

As retinal vessels (e.g., right angle venules) descend from the deep capillary plexus toward the pigment epithelium, reactive pigment epithelial hyperplasia may develop, as seen in these patients with Mactel type 2.

This patient developed progressive pigment clumping associated with a right angle venule during an observational period of 6 years.

Crystals

These patients with Mactel type 2 illustrate crystalline abnormalities at the level of the vitreoretinal interface. These are generally more prominent in the temporal juxtafoveal region where the process begins. The bottom images illustrate the hyper-reflective crystals on SD-OCT at the level of the internal limiting membrane.

Top row courtesy of Dr. Y. Sato

These are adaptive optics scanning laser ophthalmoscopy images of a patient with Mactel type 2. Note the crystals assume a distribution parallel to the nerve fiber layer. There is no evidence of crystals at the level of the cone mosaic (lower right) .

This FA of a patient with mactel type 2 illustrates a prominent perfusing arteriole (A) and draining venule (V) in a looping communication within the retina.

This histopathology specimen of Mactel type 2 shows a large intraretinal venule. There is lamination of the endothelial layers and an increase in basement membrane deposition. Very few endothelial cells are present and pericytes are conspicuously absent.

Subretinal Neovascularization

This patient with Mactel type 2 has subretinal neovascularization. The proliferating vessels in the subretinal space are bright compared to the wreath of telangiectatic vessels that forms a halo around the neovascular lesion.

This patient has subretinal neovascularization (arrows) that is perfused by two arterioles (red) and a venule (blue).

This patient with Mactel type 2 developed subretinal neovascularization in the right eye with leakage and surrounding blocked fluorescence due to hemorrhage. The OCT (top right) shows a subfoveal neovascular membrane with associated retinal edema. The bottom OCTs illustrate resolution of the neovascular lesion one month (bottom left) and 3 months (bottom right) after intravitreal bevacizumab therapy and an associated macular scar.

Note the presence of subretinal neovascularization that was excised and studied histopathologically in this patient with Mactel type 2 .

Courtesy of Dr. Fred Davidoff

In this histopathological specimen of Mactel type 2, there is extension of the intraretinal vasogenic process throughout all layers of the retina, including the subretinal space. The retinal pigment epithelium is intact.

Mactel type 2 is complicated by fibrous proliferation in the retina, which can occur late in the course of the disease. Despite the fibrosis, there is minimal cystic change within the retina, as evidenced on the SD-OCT. The visual acuity was surprisingly good at 20/40.

This patient experienced progression through the various stages of Mactel type 2. In the images on the left, the typical early findings of Mactel 2 are illustrated including perifoveal graying and telangiectasia. In the images on the right, the patient has progressed to the proliferative stage. A fibrovascular scar developed 3 years after the initial diagnosis. Note the fibrosis extends from the pre-retinal to the subretinal space with multiple retinal–subretinal anastomoses.

Treatment

In the past, laser photocoagulation was used to obliterate subretinal neovascularization in patients with Mactel type 2 but this approach has largely been abandoned with the advent of anti-VEGF therapy. This patient presented with macular hemorrhage secondary to subretinal neovascularization (arrows upper left) and Mactel type 2. There is a perfusing arteriole and draining venule seen on the FA on the foveal side of the membrane. Laser photocoagulation treatment was carried out to ablate the neovascular complex. A dense pigmented and atrophic scar ensued with central foveal sparing. The FA showed obliteration of the subretinal neovascularization with a concentric rim of staining. Beneath the fovea and beyond, there are telangiectatic changes (arrows lower middle) . The fellow eye is shown in the upper right and lower right images. A 12 year follow-up on this patient showed no progression in either eye after the laser photocoagulation treatment.

Intravitreal anti-VEGF therapy has also been attempted to reverse the vascular abnormalities and leakage in the non-proliferative stages of Mactel type 2, but there appears to be no long term functional benefit to VEGF blockade. Here is an example of a patient treated with intravitreal ranibizumab with reduced leakage and decreased retinal thickness after three injections.

This patient developed subretinal neovascularization in the right eye (top row) and received 15 consecutive monthly bevacizumab injections. After 12 months, the exudation resolved and a macular scar developed. After 2 years (middle right) and 3 years (bottom) the scar stabilized with no evidence of recurrence.

Radiation Retinopathy

Radiation retinopathy may occur from direct radiation treatment of the head, neck, or total body. The retinal abnormalities induced by radiation are similar to the microvascular findings in other diseases such as diabetes, venous occlusive disease, and even primary telangiectatic disorders. Retinal hemorrhages, CWS, perivascular sheathing, macular edema, and neovascularization may develop. In some patients, radiation can induce choroidal and optic nerve complications as well.

This patient received radiation for a brain tumor. Note the retinal hemorrhages and exudates, sheathed vessels, and telangiectatic and aneurysmal abnormalities. Early optic nerve atrophy may also be present.

This patient (left) had proton beam irradiation for a choroidal melanoma. Radiation retinopathy with intraretinal hemorrhages, lipid exudation, and macular edema are present. Note the irradiated choroidal melanoma superonasal to the optic disc (left) . Note the vascular sheathing secondary to radiation retinopathy (right) in this second case. Optic nerve head atrophy is present and a treated choroidal melanoma is noted at the inferonasal border of the nerve.

Courtesy of Dr. Evangelos Gragoudas

This patient developed a pale optic disc, intraretinal hemorrhages, macular edema, and possible inferotemporal BRVO following proton beam irradiation for a choroidal melanoma. Note the sheathed vessel inferiorly near the irradiated choroidal melanoma.

This patient developed significant macular edema and lipid exudates after receiving plaque brachytherapy for a choroidal melanoma in the temporal periphery of the left eye (top and middle). The lower OCT image shows marked improvement of the edema following one intravitreal injection of bevacizumab, although persistent exudates are still noted at the level of the outer plexiform layer immediately beneath the deep capillary plexus.

Note the presence of severe cystoid macular edema in this patient after plaque brachytherapy for uveal melanoma (top) . After five months of intravitreal bevacizumab therapy there was no improvement (middle) . Following intravitreal triamcinolone therapy, the macular edema resolved and the vision improved (bottom) .

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