Angioid Streaks Clinical Presentation

Visual acuity is normal unless a leakage, bleeding, or Bruch membrane dehiscence involves the central macula. Distorted central vision (metamorphopsia) and micropsia can be early signs of macular involvement.

Ophthalmoscopic findings

At times, angioid streaks can be difficult to identify unless a careful examination of the posterior pole is performed.

Angioid streaks usually present as linear gray or dark red lines with irregular serrated edges lying beneath normal retinal blood vessels. The streaks intercommunicate in a ringlike fashion around the optic disc in 27% of cases and radiate outward in a tapering fashion from the peripapillary area in 73% of patients. The streaks run a convoluted course and tend to terminate abruptly. Angioid streaks usually do not extend past the equator. Associated findings in patients with angioid streaks are as follows:

• Peau d'orange or leopard skin spotting, consisting of speckled yellowish mottling of the posterior pole mostly apparent in the temporal macula. This finding may antedate the appearance of angioid streaks. It is seen more frequently in patients with PXE and is caused by alterations at the level of the Bruch membrane as demonstrated by the diffuse pattern of hyperfluorescence on indocyanine green angiography (ICGA). Confluent areas of opacification visualized on imaging represent calcium deposition within the Bruch membrane, termed coquille d’oeuf (egg shell). It is hypothesized that calcium deposition weakens the Bruch membrane and subsequently leads to fractures, producing a cracked–egg-shell appearance. ^[8]
• Peripapillary chorioretinal atrophy, focal peripheral chorioretinal scars (salmon spots), and reticular pigment dystrophy of the macula may be present at the time of diagnosis.
• Optic nerve head drusen (hyaline bodies) may antedate the appearance of angioid streaks, and they may be the earliest clinical manifestations of PXE. As many as 25% of patients with angioid streaks have clinical or echographic evidence of disk drusen. These hyaline bodies were associated with neovascularization in the peripapillary area, and, in some patients, they were associated with acute visual loss due to the pressure effect on the optic nerve head.
• Crystalline bodies typically are seen in the midperipheral fundus or inferior to the optic nerve. They are multiple, round, small, and subretinal lesions. Usually, these crystalline bodies cause some atrophy of the retinal pigment epithelium (RPE). In older patients, peripheral retinal scars and calcifications can be seen. ^[9]
• Optic atrophy may be seen in patients with Paget disease of the bone. It cannot be explained solely on the basis of bony compression.
• Papillophlebitis has been reported as an incidental finding in a female patient with angioid streaks who received a progestin implant. ^[10]

Severe visual impairment is caused by one of the following conditions in 70% of cases:

• CNV with subsequent serous and hemorrhagic detachment of the fovea (most serious complication)
• CNV development occurs in 72-86% of all patients over time. ^[11] Once a patient develops CNV in one eye, it becomes bilateral in 50% within 18 months of the initial diagnosis. ^[12]
• Choroidal rupture secondary to trivial trauma with secondary hemorrhage involving the fovea
• Foveal involvement by a streak with damage to RPE and choriocapillaris (may result in permanent loss of central visual acuity)

Idiopathic

In 50% of patients with angioid streaks, no associated systemic disease is present.

Systemic association

PXE is an uncommon inherited disorder of connective tissue. It has generalized effects on the elastin fibrils in the dermis, arterial walls, heart, gastrointestinal (GI) tract, and Bruch membrane, resulting in mineralization and deposition of phosphorus. The 4 types of inheritance of PXE include 2 of which are autosomal dominant and 2 of which are autosomal recessive. It is the most common systemic disorder associated with angioid streaks. Diagnosing PXE is important because 85% of patients develop ocular involvement, usually after the second decade of life. The combination of PXE and ocular involvement is referred to as Grönblad-Strandberg syndrome.

Histologically, degenerative changes and calcifications of the elastic tissues in the skin and arteries are present. The following systemic findings may help the ophthalmologist to confirm the diagnosis of angioid streaks secondary to PXE, as well as to take care of complications.

Dermatologic findings include yellow papules, "chicken skin" arranged in a linear or reticulate pattern, in plaques, over the side of the neck, antecubital fossae, axillae, groin, and paraumbilical area.

Cardiovascular manifestations include accelerated hypertension at an earlier age due to atherosclerosis, which may be related to renovascular disease, premature coronary artery disease, peripheral vascular disease, and mitral incompetence.

Some patients develop genitourinary bleeding as part of PXE.

Neurologic findings may include cerebrovascular accidents, intracranial aneurysms, and cerebral ischemia.

Paget disease

Paget disease is a chronic, progressive, and in some cases inherited disease, characterized by bone deformity. It may be confined to a few bones, or in some patients, it represents a generalized abnormality that gives rise to enlargement of the skull, kyphoscoliosis, deafness, and deformities of long bones. However, angioid streaks occur in fewer than 2% of patients. Osteoclastic activity with an osteoblastic reaction occurs. Although the etiology is unknown, some clinicians believe it is related to a slow virus infection, measles, or respiratory syncytial virus. Both males and females are affected equally.

Ehlers-Danlos syndrome

Ehlers-Danlos syndrome is a rare autosomal dominant disorder of collagen resulting from a deficiency of hydroxylysine. Ocular findings include epicanthal folds, keratoconus, high myopia, retinal detachment, blue sclera, ectopia lentis, and angioid streaks. Systemic associations include the following:

• Skin and musculoskeletal - Thin hyperplastic skin that heals poorly, hyperextensible joints that may predispose to recurrent falls, hydrarthrosis, and pseudotumor formation over elbows and knees

• Cardiovascular disease consists of bleeding diathesis, dissecting aneurysms, spontaneous rupture of large blood vessels, and mitral prolapse.

• Others - Diaphragmatic hernias and diverticulum of the GI and respiratory tracts

Hemoglobinopathies

Hemoglobinopathies that are occasionally associated with angioid streaks include the following:

• Homozygous sickle cell disease (Hb-SS)

• Sickle cell trait (Hb-AS)

• Sickle cell thalassemia (Hb-thal)

• Sickle cell hemoglobin (Hb-SC)

• Hemoglobin H (Hb-H)

• Homozygous B-thalassemia major

• Intermedia

• Minor and hereditary spherocytosis

Advancing age and ethnicity

The frequency of angioid streaks increases with age; it is about 1.5% in younger patients and increases to 22% in older patients. Complications, such as macular degeneration and choroidal neovascular membranes, are uncommon in this subgroup of patients with angioid streaks. In general, choroidal neovascular membranes (CNVM) and serous detachments of the macula are less common in black patients.

Other systemic diseases

Other systemic diseases associated with angioid streaks include the following:

• Aagenaes syndrome (lymphedema cholestasis syndrome 1) ^[13]
• Abetalipoproteinemia
• Acromegaly
• Dwarfism
• Diabetes mellitus
• Hemochromatosis
• Facial angiomatosis
• Idiopathic thrombocytic purpura
• Chronic familial hyperphosphatemia
• Hypercalcinosis
• Hyperphosphatemia ^[6]
• Diffuse lipomatosis
• Acquired hemolytic anemia
• Myopia
• Neurofibromatosis
• Epilepsy
• Senile elastosis
• Sturge-Weber syndrome
• Trauma
• Tuberous sclerosis

Subretinal hemorrhage and serous detachment are common complications of angioid streaks. Incidence of subretinal hemorrhage and serous detachment caused by choroidal neovascularization is high, about 85% of all patients with PXE and 10-15% of patients with Paget disease of the bone. The disease is bilateral in all patients with an average age of onset older than 25 years. The greater the length and width of the angioid streaks, the greater the risk of CVN. The risk is even higher if the streaks are within 1 disc diameter of the foveola. ^{[5, 6, 7]} Ungureanu et al reported a case of neovascular glaucoma secondary to angioid streaks. ^[14]