Förster-Fuchs Retinal Spot

oPatientPlus articles are written by UK doctors and are based on research evidence, UK and European Guidelines. They are designed for health professionals to use, so you may find the language more technical than the condition leaflets.

Synonyms: Forster-Fuchs spot, Fuchs retinal spot, disciform degeneration in myopia and choroidal neovascularisation in myopia

Förster-Fuchs retinal spot is a raised, pigmented, circular scar on the retina. This particular form of retinal scarring follows areas of degeneration and neovascularisation related to high myopia. It is named after Ernst Fuchs, who described a pigmented lesion in 1901, and Carl Förster, who described neovascularisation of the retina in 1862.

Myopia ('short-sightedness') arises as a result of a globe with high axial length (ie a long globe as measured from front to back) - see separate article Refraction and Refractive Errors for more details. In some highly myopic patients, the axial length never stabilises - a condition known as progressive myopia.

In patients with high myopia (6 dioptres or more) and progressive myopia, the back of the eye is prone to degenerative change characterised by pale, well circumscribed, tessellated patches of chorioretinal atrophy. These occur both centrally and peripherally, and their size is related to the degree of myopia. They are prone to develop breaks in one of the retinal layers - the Bruch's membrane - which results in cracking throughout the lesion (like lacquer cracks). Subsequent neovascularisation and macular haemorrhage lead to a pigmented scar known as the Förster-Fuchs spot. This raised, pigmented, circular lesion develops after the macular haemorrhage has been absorbed.

Other changes in high myopics include a tilted disc with associated atrophy, early age posterior vitreous detachment, zonular dehiscence (ie the zonules holding taut the capsular bag containing the crystalline lens) and pigment dispersion syndrome.

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  • The prevalence of progressive myopia shows geographical variation (eg, it is high in Spain and in Japan). However, generally it is thought to occur in 1-10% of myopic eyes.
  • Up to one third of severely myopic eyes can show degenerative changes.[1]
  • This can strike at any age but it is a very significant cause of blindness in young people in developed countries.
  • A study in Australia found the spots in 3 of 3,654 elderly people, giving a prevalence of 0.1% in this age group.[2]

This is a condition seen in high myopia. There may be genetic and environmental influences (excessive near work) contributing to the myopia. Other associations with myopia include:

Symptoms

  • Deteriorating vision (increasing myopia).
  • Distortion of sight of straight lines near the fovea.
  • There may also be complaints of visual distortion with wavy lines (metamorphopsia).
  • Central or paracentral scotoma.
  • Impairment of colour vision.
  • Prolonged recovery from light stress.
  • As in macular degeneration, therefore, central vision is affected.

Signs

  • Ability to read the Snellen chart may deteriorate by two lines or more in a fairly short space of time.
  • The Förster-Fuchs spot may be seen near the fovea but there are wide variations in the appearance.
  • The neovascularisation phase is short, and vision is lost early.

Fluorescein angiography shows subretinal neovascularisation from the choroid as the basic underlying disease process in most cases.[3] 

Drugs

Pharmacological treatment is a new area with studies just emerging now. Intravitreal bevacizumab is the most recent candidate drug.[5] This needs to be given every three months (the invasive nature of intravitreal injections means there are risks of complications) but a 12-month prospective study has shown some promising results - albeit on a very small number of eyes.[6]

Surgical

Conventional treatments of laser photocoagulation or surgical extraction of the area of neovascularisation have shown limited effectiveness, partly due to the limitations of not being able to laser over the foveal area (this destroys it and central vision with it). Newly developed treatments such as foveal translocation or photodynamic therapy have had favourable results in the short term.[7] This was particularly so in the younger patient presenting with larger lesions but with a better initial visual acuity.[8] More randomised controlled trials are needed.

A vitrectomy may be carried out to prevent the particular type of posterior vitreous detachment (PVD) which affects these eyes from leading to a traction maculopathy.[9] In one study, surgical excision of subfoveal choroidal neovascular membranes in high myopia brought improvement of visual acuity of at least two lines in 45% and no change in 37%.[10] Another trial showed similar results with the visual acuity improved by 2 or more Snellen lines in 39%, decreased in 35% and unchanged in 26%.[11] 

Without treatment, atrophy occurs around the affected area.[7] The new vessels also cause traction on the retina which can lead to a retinal detachment. These patients are also at greater risk of developing macular holes.[9][12]

A study from Moorfields Eye Hospital in 1983 showed a generally poor prognosis without intervention, with 43% of the patients losing two or more lines of vision, while 60% were less than or equal to 6/60 at last follow-up.[13] There was a direct relationship between visual acuity and the distance of the neovascular tissue from the fovea, and an inverse relationship between acuity and the size of the lesion.

Older patients tend to have a poorer outcome than younger ones.[14]

Optical coherence tomography can detect this condition at its early stages so that early intervention may take place.[1] 

Further reading & references

  1. Panozzo G, Mercanti A; Optical coherence tomography findings in myopic traction maculopathy. Arch Ophthalmol. 2004 Oct;122(10):1455-60.
  2. Vongphanit J, Mitchell P, Wang JJ; Prevalence and progression of myopic retinopathy in an older population. Ophthalmology. 2002 Apr;109(4):704-11.
  3. Bhatt NS, Diamond JG, Jalali S, et al; Choroidal neovascular membrane. Indian J Ophthalmol. 1998 Jun;46(2):67-80.
  4. Ranibizumab for treating choroidal neovascularisation associated with pathological myopia; NICE Technology Appraisal, November 2013
  5. Chang LK, Spaide RF, Brue C, et al; Bevacizumab treatment for subfoveal choroidal neovascularization from causes other than age-related macular degeneration. Arch Ophthalmol. 2008 Jul;126(7):941-5.
  6. Gharbiya M, Allievi F, Mazzeo L, et al; Intravitreal bevacizumab treatment for choroidal neovascularization in pathologic myopia: 12-month results. Am J Ophthalmol. 2009 Jan;147(1):84-93.e1. Epub 2008 Sep 6.
  7. Ohno-Matsui K, Yoshida T; Myopic choroidal neovascularization: natural course and treatment. Curr Opin Ophthalmol. 2004 Jun;15(3):197-202.
  8. Ruiz-Moreno JM, Amat P, Montero JA, et al; Photodynamic therapy to treat choroidal neovascularisation in highly myopic patients: 4 years' outcome. Br J Ophthalmol. 2008 Jun;92(6):792-4.
  9. Panozzo G, Mercanti A; Vitrectomy for myopic traction maculopathy. Arch Ophthalmol. 2007 Jun;125(6):767-72.
  10. Bottoni F, Perego E, Airaghi P, et al; Surgical removal of subfoveal choroidal neovascular membranes in high myopia. Graefes Arch Clin Exp Ophthalmol. 1999 Jul;237(7):573-82.
  11. Uemura A, Thomas MA; Subretinal surgery for choroidal neovascularization in patients with high myopia. Arch Ophthalmol. 2000 Mar;118(3):344-50.
  12. Shimada N, Ohno-Matsui K, Yoshida T, et al; Development of macular hole and macular retinoschisis in eyes with myopic choroidal neovascularization. Am J Ophthalmol. 2008 Jan;145(1):155-161. Epub 2007 Nov 7.
  13. Hampton GR, Kohen D, Bird AC; Visual prognosis of disciform degeneration in myopia. Ophthalmology. 1983 Aug;90(8):923-6.
  14. Tabandeh H, Flynn HW Jr, Scott IU, et al; Visual acuity outcomes of patients 50 years of age and older with high myopia and untreated choroidal neovascularization. Ophthalmology. 1999 Nov;106(11):2063-7.

Disclaimer: This article is for information only and should not be used for the diagnosis or treatment of medical conditions. EMIS has used all reasonable care in compiling the information but make no warranty as to its accuracy. Consult a doctor or other health care professional for diagnosis and treatment of medical conditions. For details see our conditions.

Original Author:
Dr Olivia Scott
Current Version:
Peer Reviewer:
Dr Hannah Gronow
Last Checked:
21/03/2014
Document ID:
2166 (v23)
© EMIS