Macular degeneration

Notes

## Basic introduction

  • Macula is an oval-shaped pigmented area near the center of the retina
  • Macular degeneration is a group of progressive eye conditions with deterioration of macula and vision
  • Age-related macular degeneration (AMD) is also known as Age related maculopathy (ARM)
  • Types of macular degeneration (the list is not exhaustive):
  • AMD
  • Juvenile Macular Degeneration[a]
  • Macular Dystrophy Stargardt’s Disease
  • Two classes of AMDs are[c]:
  • Dry or non-neovascular or atrophic AMD:

|||This constitutes 85-95% of all cases of AMD 

|||It is usually the early stage of the disease

|||It is less severe than Wet AMD

  • Wet or neovascular or exudative AMD:

   |||It also known as exudative macular …..degeneration

   |||Although it affects only 10-15% of …..cases of AMD, it causes 90% of the …..severe vision loss due to AMD

   |||It can be occult or classic

  |||Wet AMD occurs when the membrane              underlying the retina thickens and           breaks. This leads to the reduced oxy      gen supply to the macula that

     stimulates the growth of new blood vessels, which grow through the              breaks of the membrane behind the         retina towards the macula

     occasionally raising the retina.

  • Risk factors for macular degeneration include:
  • Age
  • Family history of the disease
  • Hypertension
  • Obesity
  • Patient with a lighter eye color
  • Smoking
  • Cardiovascular disease
  • Some medications with adverse effect on macula
  • Female gender
  • White race
  • Hypercholesterolemia
  • Hyperopia

## Statistics

  • ARMD is the most common cause of irreversible vision loss in USA at the age of > 60 yrs[a]
  • The global prevalence of advanced AMD is 1.6%[d]
  • Based on the digital retinal images, the prevalences of early and late AMD among the study population aged 50 yrs and above in Nakuru, Kenya, were 11.2% and 1.2%, respectively. The prevalences of early and late AMD judged by slit lamp biomicroscopy were 6.7% and 0.7%, respectively
Symptoms
  • Loss of sharp central vision (scotoma)
  • Blurred vision
  • Challenges in color vision
  • Difficulty seeing fine detail
  • Distorted vision
  • Vague complaints on vision
  • Drusen
  • Subretinal fluid or hemorrhage
  • Geographic atrophy
  • Subretinal fibrosis
  • Changes in retinal pigment epithelium (RPE)
Diagnosis
  • An Amsler grid
  • The grids look wavy in early Dry AMD
  • Blind spots in Dry AMD
  • Fluorescein angiography:
  • Presence of drusen (yellowish waste deposits) on the retina in case of Dry AMD[d]
  • Broken membrane behind the retina towards the macula
  • Optical coherence tomography (OCT)
Differential
  • Ocular histoplasmosis syndrome
  • Pathologic myopia
  • Chroidal rupture
  • Angioid streaks
  • Choroidal tumors
  • Polypoidal choroidal vasculopathy
  • Central serous chorioretinopathy
  • Pattern dystrophy
  • Cuticular drusen
  • Drug toxicity
Prevention
  • None is known
Reference

1. Glazer, L. C., & Dryja, T. P. (2002). Understanding the etiology of Stargardt's disease. Ophthalmology Clinics, 15(1), 93-100.

2. Gupta, O. P., Brown, G. C., & Brown, M. M. (2007). Age-related macular degeneration: the costs to society and the patient. Current opinion in ophthalmology, 18(3), 201-205

3. Ferris, F. L., Fine, S. L., & Hyman, L. (1984). Age-related macular degeneration and blindness due to neovascular maculopathy. Archives of ophthalmology, 102(11), 1640-1642.

4. Klein, R., Klein, B. E., & Linton, K. L. (1992). Prevalence of age-related maculopathy: the Beaver Dam Eye Study. Ophthalmology, 99(6), 933-943

5. Mathenge, W., Bastawrous, A., Peto, T., Leung, I., Foster, A., & Kuper, H. (2013). Prevalence of age-related macular degeneration in Nakuru, Kenya: a cross-sectional population-based study. PLoS Med, 10(2), e1001393..

Management
'-Deoxy-" '-Difluorocytidine
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