Collaborative Case #002: High and Dry

While all of the above conditions are characterized by atrophic changes, this patient displays atrophic spots within the posterior pole and scleral secondary to retinal and choroidal thinning. Her history of cataract extraction at a young age and laser retinopexy are also hints of high myopia as these are common complications associated with Degenerative Myopia.

Macular OCT is the only reliable way to asses distinctive layers of the retina and rule out Choroidal Neovascularization (CNV), a vision-threatening complication of Degenerative Myopia.

Our main concern in this patient is the presence of choroidal neovascularization (CNV), which can be difficult to spot when we take into account the complexity of the appearance of her fundus. The macular OCT did not show any subretinal fluid or reflectivity structure, ruling out CNV.

Because no Choroidal Neovascularization (CNV) is present, observation is recommended.

Pathologic myopia, also known as degenerative myopia and progressive myopia, is one of the leading causes of visual impairment in the world and is caused by progressive, anteroposterior elongation of the globe. Differential diagnosis may include serpiginous choroiditis or presumed ocular histoplasmosis syndrome, due to the patchy chorioretinal atrophic spots within the posterior pole and the potential for CNV. However, a history of progressive high and increasing myopia should direct the diagnosis to a myopic etiology.

Common symptoms of pathologic myopia include a slow or abrupt decrease in visual acuity and metamorphopsia secondary to macular changes.

MACULAR CHANGES ASSOCIATED WITH PATHOLOGIC MYOPIA

Pathologic myopia can lead to several ocular complications, including CNV, retinal detachment, lacquer cracks, and retinal atrophy.

CNV

Thin and fragile new blood vessels can grow into the open areas created by lacquer cracks and retinal atrophy, which can lead to scarring and vision loss. On OCT, myopic CNV presents as a highly reflective area contiguous above the RPE (type 2 CNV). Intravitreal anti-VEGF therapy is the standard of care and first-line treatment for myopic CNV, but treatment is not as frequent as that required for AMD type 1.

Retinal Detachment

Retinal stretching as a result of pathologic myopia can lead to retinal tearing and detachment, which can cause symptoms such as flashes of light and dark floaters. A tear that hasn't yet progressed to a detachment may be treated with either laser surgery or photocoagulation as an outpatient procedure. Retinal detachments, on the other hand, require surgical repair.

Lacquer Cracks

Retinal stretching can also cause breaks in the macula and in Bruch membrane called lacquer cracks.

Retinal Atrophy

Retinal stretching can cause the retina to thin, which, over time, can cause the retina to atrophy, which can damage your vision. Atrophy is typically progressive, associated with age, axial length, myopic CNV, and posterior staphyloma.

DIAGNOSTIC MODALITIES

Common diagnostic modalities used to assess the macula for pathologic myopia include fundus photography, macular OCT, OCTA, fundus autofluorescence, fluorescein angiography, and visual fields.

OCT is an important tool and should be performed periodically on patients with high or pathologic myopia to rule out macular conditions such as CNV. If CNV is suspected, OCTA or fluorescein angiography should be performed. Lastly, fundus autofluorescence is useful in evaluating the area of functional retina available within the posterior pole.