Basal Laminar Drusen

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Basal laminar drusen is an uncommon that was originally thought to be distinct from age-related macular degeneration, but is now considered to be part of a spectrum of disease that includes age-related macular degeneration. Findings include numerous small yellow drusen on examination, which are more obvious on fundus auto-fluorescence. Fluorescein angiography (FA) demonstrates punctuate areas of early staining throughout the macula, with a “stars in the sky" pattern. The development of vitelliform macular lesions, choroidal neovascularization (CNV), and geographic atrophy may cause vision loss.

Contents

Disease Entity

Basal laminar drusen have also been referred to as diffuse drusen, cuticular drusen, and early-adult onset grouped drusen in the literature.

Disease

Basal laminar drusen are a subtype of early onset drusen. It is considered part of a spectrum that includes age-related macular degeneration

Etiology

The etiology is not well understood.

Risk Factors

Many risk factors for age-related macular degeneration are risk factors for basal laminar drusen.

Cigarette Smoking
Current cigarette smoking is associated with basal laminar drusen, with an odds ratio of 2.06. This association is less strong than that between current smoking and age-related macular degeneration. A history of smoking is not associated with basal laminar drusen.[1]


Genotype
Presence of the complement factor H Y402H variant is associated with basal laminar drusen, with a statistically significant odds ratio of 2.88.[1]

Family History
In one cohort, 44% of patients with basal laminar drusen reported a family history of age-related macular degeneration.[2]

Gender
In one large case series, there was a trend toward female gender being a risk factor for basal laminar drusen, but this was not statistically significant.[1]

General Pathology

Initially, basal laminar drusen were thought to be distinct from the drusen of age-related macular degeneration based on the differences on fundus examination, autofluorescence, FA and histopathology. As the name suggests, Gass and colleagues described basal laminar drusen as areas of thickening of the retinal pigment epithelium basement membrane.[3] More recently, however, Russell and colleagues have shown similarities in basal laminar drusen and drusen from age-related macular degeneration in terms of their lipoprotein composition, ultrastructure, and sub-retinal pigment epithelium localization.[4]

Pathophysiology

The pathophysiology is poorly understood. Because of the association with the complement factor H Y402H variant, it is hypothesized that overactivity of the complement cascade is a contributing factor.[5]

Diagnosis

The diagnosis of basal laminar drusen is clinical, based on dilated fundus examination, fundus autofluorescence and fluorescein angiography.

History

Young adults may be found to have basal laminar drusen on routine examination. Patients may have a family history of age-related macular degeneration. In cases that present with complications such as geographic atrophy or CNV, visual complaints may be present.

Physical examination

Dilated fundus examination will reveal numerous, small yellow drusen. Vitelliform pigment epithelial detachments, which are often bilateral, may be present. CNV or geographic atrophy may be present.

Signs

Multiple small, yellow drusen in a young adult.

Symptoms

Uncomplicated cases may be asymptomatic. Patients with vitelliform pigment epithelial detachment, CNV, or geographic atrophy may present with decreased visual acuity, or distortion.

Clinical diagnosis

Basal laminar drusen is diagnosed clinically. The presence of multiple, diffusely distributed drusen which are more numerous on fluorescein angiography in a young adult is classic.

Diagnostic procedures

Fundus autofluorescence often demonstrates more numerous hyperautoflurorescent drusen than seen on examination. Fluorescein angiography reveals more small drusen than seen on fundus examination, spread diffusely throughout the macula, with a “stars in the sky” appearance.  Optical coherence tomography may be helpful in evaluatinf for CNV.


Differential diagnosis

The differential diagnosis includes other conditions associated with drusen, such as autosomal dominant drusen (Malattia Leventinese), pattern dystrophy, and age related macular degeneration. In patients with vitelliform pigment epithelial detachment, Best disease and adult vitelliform foveomacular dystrophy are also a consideration.

Management

Patients with basal laminar drusen should be monitored for the development of vitelliform lesions, CNV, or geographic atrophy which may be visually significant.

General treatment

Treatment is indicated in patients who develop CNV, which may affect or threaten vision. Vision loss due to geographic atrophy is not treatable at this time, however patients with geographic atrophy should continue to be observed for the development of CNV. 

Medical therapy

In cases of isolated basal laminar drusen, no therapy is indicated. Patients should be observed to monitor for the development of CNV or geographic atrophy. CNV should be treated when detected. Photodynamic therapy has been shown to be effective in cases of basal laminar drusen complicated by CNV.[6] Vitelliform pigment epithelial detachments may be observed and have been reported to resolve spontaneously;[3] treatment with photodynamic therapy worsens vision in these cases.[7]  It is unclear whether AREDs vitamins, shown to have some benefit for patients with age-related macular degeneration, are of benefit in patients with basal laminar drusen.[8]

Medical follow up

Patients with basal laminar drusen should be followed regularly to monitor for development of CNV. Patients who develop CNV should be monitored frequently to assess response to treatment.


Complications

As noted above, the main complications are the development of CNV, which has been reported in 21% of cases, and geographic atrophy, which has been reported in 11% of cases.[2]

Prognosis

Visual acuity has been reported as worse than 20/100 in the better seeing eye in 22% of patients.[2]

Additional Resources

www.omim.org/entry/126700

References

  1. 1.0 1.1 1.2 van de Ven JP, Boon CJ, Fauser S, Hoefsloot LH, Smailhodzic D, Schoenmaker-Koller F, Klevering J, Klaver CC, den Hollander AI, Hoyng CB. Clinical evaluation of 3 families with basal laminar drusen caused by novel mutations in the complement factor H gene. Arch Ophthalmol. 2012; 130:1038-47.
  2. 2.0 2.1 2.2 Grassi MA, Folk JC, Scheetz TE, Taylor CM, Sheffield VC, Stone EM. Complement factor H polymorphism p.Tyr402His and cuticular Drusen. Arch Ophthalmol. 2007; 125:93-7.
  3. 3.0 3.1 Gass JD, Jallow S, Davis B. Adult vitelliform macular detachment occurring in patients with basal laminar drusen. Am J Ophthalmol. 1985; 99:445-59.
  4. Russell SR, Mullins RF, Schneider BL, Hageman GS. Location, substructure, and composition of basal laminar drusen compared with drusen associated with aging and age-related macular degeneration. Am J Ophthalmol. 2000; 129:205-14.
  5. Boon CJ, Klevering BJ, Hoyng CB, Zonneveld-Vrieling MN, Nabuurs SB, BloklandfckLRE, Cremers FP, den Hollander AI. Basal laminar drusen caused by compound heterozygous variants in the CFH gene. Am J Hum Genet. 2008; 82:516-23.
  6. Guigui B, Martinet V, Leveziel N, Coscas G, Soubrane G, Souied EH. Photodynamic therapy for choroidal neovascularisation secondary to basal laminar drusen. Eye (Lond). 2009; 23:2115-8.
  7. Ergun E, Costa D, Slakter J, Yannuzzi LA, Stur M. Photodynamic therapy and vitelliform lesions. Retina. 2004; 24:399-406.
  8. Age-Related Eye Disease Study Research Group. A randomized, placebo-controlled, clinical trial of high-dose supplementation with vitamins C and E, beta carotene, and zinc for age-related macular degeneration and vision loss: AREDS report no. 8. Arch Ophthalmol. 2001; 119:1417-36.

Acknowledgments

Claudia Krispel, MD, PhD for critical review of this article.
 

Original article contributed by: Fatemeh Rajaii, MD, PhD
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