Senescent Cells as Drivers of Age-Related Diseases
Shamim I. Ahmad in Aging: Exploring a Complex Phenomenon, 2017
Macular degeneration or age-related macular degeneration (AMD) is one of the leading causes of vision loss worldwide [195]. AMD incidence increases with age and has become a public health concern, especially in growing populations [196,197]. AMD is considered an incurable eye condition caused by the deterioration of macula, a small central area of the retina that provides visual acuity [196]. Two main types of macular degeneration exist: dry and wet form [198,199]. Dry from is characterized by the presence of small yellow crystalline deposits called drusen in the macula [200]. Typically, few small drusen do not significantly cause changes in vision, but over time, these drusen may increase in size and number and could lead to distorted vision. In more advanced stages, retinal pigment epithelial (RPE) cells undergo atrophy, reducing the central vision, and affecting color perception [201,202]. On the other hand, the wet form is the more severe type of AMD. In the wet form, blood vessels develop at the layer behind the retina called the choroid. These blood vessels eventually leak blood and fluid into the retina, causing the macula to swell and rapidly damage the central vision [199,200].
Laser prophylaxis for age-related macular degeneration
A Peyman MD Gholam, A Meffert MD Stephen, D Conway MD FACS Mandi, Chiasson Trisha in Vitreoretinal Surgical Techniques, 2019
The study included 882 patients with high-risk drusen in one eye (243 unilateral eligible eyes) and patients with bilateral drusen (1278 bilateral eligible eyes), both randomized to treatment versus observation. The treatment technique was the same as in our pilot study, with a macular grid of subthreshold laser burns applied with an 810 nm diode laser. Although the follow-up was up to 5 years, the study conclusions are based on the first 36 months of data. In the unilateral study arm, treatment did not reduce the incidence of CNV, and in fact was associated with a significantly higher event rate compared with observation eyes (21% in treated eyes vs 14% in observed eyes; p = 0.02), which led to a premature halt in the enrollment of patients in this study arm. Also, treated eyes did not improve in visual acuity compared with control eyes. In bilateral eligible eyes, treatment had no effect on the prevention of CNV and only a modest effect on improving visual acuity. When the subset of eyes with a baseline visual acuity between 20/30 and 20/63 was compared with controls, more eyes experienced a 2-line gain in vision at 24 months’ follow-up, although the difference was not statistically significant. The rate of clinically apparent drusen resorption was significantly higher in treated eyes than in controls from 12 to 36 months. Similarly, in bilateral eligible patients, treatment had no effect on the development of CNV. The investigators concluded that this type of laser treatment does not prevent the development of exudative ARMD in high-risk drusen eyes.19
Macular disorders
Thomas H. Williamson in Vitreoretinal Disorders in Primary Care, 2017
Patients with extensive small drusen, non-extensive intermediate size drusen or pigment abnormalities have only a 1.3% 5-year probability of progression to advanced AMD according to the age-related eye disease study (AREDS).78 Those with extensive intermediate size drusen, at least one large drusen, non-central geographic atrophy in one or both eyes or advanced AMD or vision loss due to AMD in one eye are at risk of vision loss from advanced AMD in up to 50% (large drusen with pigmentary changes) after 5 years.79 In wet AMD, there is fluid leakage in or under the retina from pigment epithelial detachment or choroidal neovascular membranes. Choroidal neovascular membranes are vascular membranes that commence in the choroid and penetrate the retinal layers.
Are macular drusen in midlife a marker of accelerated biological ageing?
Published in Clinical and Experimental Optometry, 2023
Graham A Wilson, Kirsten Cheyne, Sandhya Ramrakha, Antony Ambler, Gavin SW Tan, Avshalom Caspi, Ben Williams, Karen Sugden, Renate Houts, Rachael L Niederer, Tien Yin Wong, Terrie E Moffitt, Richie Poulton
The eye is a good model for studying ageing; not just because it can be imaged non-invasively, but because it allows non-invasive imaging of neurological and vascular tissue.8 Macular drusen are yellow deposits deep within the retina that are easily identifiable on clinical examination or retinal photography. Drusen are accumulations of extracellular debris and come in a range of morphologies.9 While the initiation and growth of drusen and the mechanisms underlying drusen remain a key area of research, it is well established that drusen are the hallmark of age-related macular degeneration (AMD), a disease for which age is the strongest risk factor.10,11 Estimated 8.4 million people worldwide have moderate-to-severe vision loss caused by AMD.12
Optometry Australia's chairside reference for the diagnosis and management of age‐related macular degeneration
Published in Clinical and Experimental Optometry, 2020
Kerryn M Hart, Carla Abbott, Angelica Ly, Susan Kalff, Jia Jia Lek, Rebecca Milston, Gary Page, Bill Robertson, Lauren Ayton
The most current clinical classification scheme for AMD is the Beckman classification2013 (Figure 1). This scheme arose from the Beckman Initiative for Macular Research Classification Committee, a panel of expert ophthalmologists, a neuro‐ophthalmologist and a methodologist.2013 The classifications are determined based on clinical examination (using common ophthalmoscopy equipment, such as an ophthalmoscope or slitlamp with accessory lenses) or evaluation of a fundus photo. Classification is based on fundus lesions within two‐disc diameters of the fovea in patients older than 55-years of age. Drusen size should be estimated based on their smallest diameter. Note, the average width of the central retinal vein at the optic disc margin is 125 μm, so drusen larger than this are considered large drusen. Medium drusen are between half and one‐full width of the vein (63–125 μm), and small drusen are less than half the vein width (< 63 μm).2013
Application of subthreshold laser therapy in retinal diseases: a review
Published in Expert Review of Ophthalmology, 2018
Spencer M. Moore, Daniel L. Chao
Interestingly, a number of studies have demonstrated that laser photocoagulation could diminish drusen size in AMD patients, although not always with obvious clinical benefit to the patient. In 2000, Roider et al. provided proof-of-concept by conducting a small nonrandomized pilot study of 26 patients with retinal pathology, finding reduction of drusen in 7/10 patients treated with ST 527 nm laser at 6 months follow-up [42]. In a retrospective analysis of 144 eyes of 144 dry AMD patients in Italy treated by CW argon 532 nm laser or ST 810 nm laser, there was no clinical benefit to ST over CW laser as measured by lack of statistical difference in VA or drusen reduction [74]. The authors found that ST laser versus CW spared patients treatment-associated reduction in contrast sensitivity [74]. When functional guidance of ST 810 nm laser was guided by pattern electroretinography (PERG), a readout typically used in glaucoma, PERG metrics were improved in a study of 158 eyes from 108 patients with AMD, although without VA improvement [19].
Related Knowledge Centers
- Bruch'S Membrane
- Retinal Pigment Epithelium
- Eye
- Macula
- Macular Degeneration
- Optic Disc Drusen
- Optic Nerve
- Ophthalmoscopy
- Optical Coherence Tomography
- Colloid