Fox TV personality Glenn Beck announced last month that he has "macular dystrophy" and that he "could go blind next year."

Mr Beck, 46, said he was having trouble focusing his eyes and went to a doctor where he was told he had macular dystrophy and that within a year it could cause him to go blind.

Mr Beck most likely has a hereditary form of retina damage, such as pattern dystrophy, adult vitelliform degeneration and Malattia Leventinese (discussed below).

As with all macular diseases, these conditions may cause loss of central vision, but do not cause "blindness" in the usual sense of the word. Macular dystrophies damage the macula in much the same way that age-related macular degeneration (AMD) does, but at a much earlier age.

In general, dystrophies are caused by a specific genetic defect that is inherited from generation to generation. Because most dystrophies are carried by a recessive gene, the disease will skip generations and only appear sporadically. Unless a person undergoes genetic testing, they have no way of knowing whether they are a carrier for a gene that causes a dystrophy, and hence whether their children are at risk for developing the disease. Both father and mother must be a carrier for their children to develop the disease.

We wish Mr Beck well, and hope he will use the publicity surrounding his eye troubles to education the public about the truth regarding macular disease.

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Drusen are rarely observed in patients less than 50 years of age. Two types of early onset drusen are commonly described: basal laminar drusen and drusen associated with Malattia Leventinese, also known as familial drusen.

This article will discuss Malattia Leventinese, a term used to describe a group of conditions associated with early onset drusen and a type of macular degeneration in young patients.

Two specific conditions were initially described in the literature as separate entities. In Robert Walter Doyne described a clinical condition associated with early onset drusen in 1899. The rare condition became known as Doyne honeycomb retinal dystrophy. In 1925, a similar condition was described in a number of individuals from a family in the Leventine Valley of southern Switzerland which thereafter became known as Malattia Leventinese ("the malady of the Leventine valley").

In 1999 it was suggested that the two disorders most likely represent different expressions of the same disease. The same genetic defect was found to exist in both conditions. Most experts now accept the two entities represent the same malady.

The hallmark finding of Malattia Leventinese is the presence of drusen in a radiating pattern throughout the macula that develop early in life (often by the second decade). These elongated drusen may also be found outside the arcades, especially nasal to the disc which is unusual in other types of macular degeneration.

Despite the impressive drusen, the vision for most patients with Malattia Leventinese remains fairly good for many years. Patients often remain asymptomatic into the fourth decade of life before they notice some decrease in vision or metamorphopsia. As the degeneration progresses, confluence of drusen and RPE atrophy can lead to visual loss. Some patients may eventually develop CNV which can dramatically decrease vision.

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A new study finds that a single intravitreal dose of Sirna-027, a small interfering RNA targeting VEGF receptor-1 (VEGFR-1), was well tolerated and that stabilization or improvement in visual acuity and foveal thickness occurred in patients with choroidal neovascularization (CNV) resulting from age-related macular degeneration (AMD) that had been unresponsive to other therapies.

Sirna-027 is a chemically modified small interfering RNA (siRNA) molecule that targets VEGFR-1 mRNA molecules. Sirna-027 reduces neovascularization in a mouse laser-induced CNV model. siRNA molecules induce gene silencing by binding to complementary target RNA molecules.

Based on positive preclinical animal studies of Sirna-027, the current phase 1 study was conducted.

The researchers found intraocular injections of a single dose of Sirna-027 were well tolerated in patients with subfoveal CNV resulting from neovascular AMD, and no dose-limiting toxicity occurred. Most adverse reactions were attributed to the intravitreal injection procedure, and all were mild or moderate in severity and transient in nature.

Some patients showed improvements in VA and foveal thickness in this study. Clinically significant improvement (>3 lines read) was documented at 1 or more visits in 9 patients (34.6%). The foveal thickness tended to decrease within 2 weeks of treatment.

The investigators conclude that siRNAs may represent a promising approach to the treatment of neovascular AMD.

WHAT IT MEANS TO YOU: This exciting new treatment modality is based on the principle of RNA interference. RNA acts as a messenger within the cell, carrying instructions from DNA within the cell's nucleus out to locations within the cell where the genetic instructions are used to build proteins. Interfering RNA intercepts and destroys the messenger RNA for specific proteins - a process known as gene silencing. In this study, the gene for a key VEGF receptor was silenced, and patients with wet AMD showed improvement. Based upon the results of this study, Phase 3 clinical trials have begun, and before long doctors may be able to offer this treatment to patients.

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A new study finds that VEGF-A165b is a potent angiogenic inhibitor in a mouse model of AMD and suggests that increasing the ratio of antiangiogenic-to-proangiogenic VEGF isoforms may be therapeutically effective in this condition.

Vascular endothelial growth factor (VEGF) is the principal stimulator of angiogenesis in wet AMD. A variety of forms of VEGF are known to exist, called isoforms. One isoform, known as VEGF-A165b, binds to the VEGF receptors but does not stimulate angiogenesis. It therefore acts as an inhibitor of the proliferative, migratory, and vasodilator effects of VEGF.

The researchers used a model of laser-induced CNV in mice to investigate VEGF-A165b. After laser injury, mice were injected with VEGF-A165b. Intraocular injection resulted in a pronounced dose-dependent inhibition of CNV. Subcutaneous administration also inhibited fluorescein leakage and neovascularization and reduced lesion size.

The researchers conclude that VEGF-A165b is an effective treatment for CNV in an animal model.

WHAT IT MEANS TO YOU: Although most isoforms of VEGF promote neovascularization ("bad VEGF"), there is at least one isoform, VEGF-A165b, that acts to inhibit CNV ("good VEGF"). Current anti-VEGF drugs, such as Lucentis and Avastin, inhibit all isoforms of VEGF (good and bad). Unfortunately, about 10% of people with AMD do not respond to Lucentis and Avastin therapy. It seems plausible that these people are producing a lot of good VEGF in addition to too much bad VEGF. Because Lucentis is unable to differentiate between the good and bad forms of VEGF it inhibits both, effectively making no difference at all in these people. This study demonstrates that it is possible to inhibit CNV by treating them with good VEGF. This may represent a promising new treatment option for people that do not respond to conventional anti-VEGF therapies.

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Fish and shellfish consumption decreases the risk of AMD, according to a new study.

Fish oil is rich in omega-3 fatty acids. There is evidence that omega-3 fatty acids protect against oxidative and inflammatory damage, which are possible pathogenic factors for AMD development. Research suggests that the AREDS vitamin-mineral supplement, increased intake of omega-3 fatty acids, and reducing dietary glycemic index are protective against AMD.

In the current study, a food frequency questionnaire was used to estimate weekly fish/shellfish consumption for each participant in the Salisbury Eye Evaluation. SEE is a study of a random sample of 2520 residents aged 65 to 84 years of Salisbury, Maryland.

The researchers found that persons with advanced AMD (both wet and dry) were significantly less likely to consume fish/shellfish high in omega-3 fatty acids.

The investigators conclude that these data support a protective effect of fish/shellfish intake against advanced AMD.

WHAT IT MEANS TO YOU: This is another in a long line of research studies that support the value of fish in fighting AMD. Both fish consumption and the use of fish oil supplements have very strong scientific evidence supporting their use in the prevention of AMD as well as in slowing its progression from early to advanced stages. AREDS 2, a randomized controlled trial currently underway that is testing the effectiveness of fish oil and other antioxidants to slow the progression of AMD, should provide definitive evidence within the next few years.

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Patients with central serous chorioretinopathy (CSC) undergoing reduced-fluence photodynamic therapy (PDT) recover faster than patients undergoing focal laser photocoagulation.

CSC is characterized by the accumulation of subretinal fluid (SRF) at the macula and is a common condition in young adults. Although CSC generally is considered a self-limiting and benign condition, some patients may experience significant visual impairment caused by recurrent attacks of CSC, persistent SRF, or RPE atrophy.

In the current study, 26 eyes of 26 patients with symptomatic CSC underwent focal laser photocoagulation or half-dose PDT.

Twelve eyes in the focal laser group and 14 eyes in the PDT group were evaluated. One month after PDT, all eyes, except one, showed complete absorption of subretinal fluid, whereas five eyes in the focal laser group showed residual subretinal fluid. Visual acuity and parameters of multifocal electroretinography improved from baseline at 1, 3 and 6 months after treatment, without any significant differences between the two groups.

The investigators conclude that compared with focal laser, half-dose PDT may facilitate earlier resolution of macular detachment and earlier recovery of central retinal function. However, at 3 months after treatment and thereafter, no difference in anatomical and functional recovery was noted between the two modalities of treatment.

WHAT IT MEANS TO YOU: This study demonstrates that reduced fluence PDT ("cold laser") may speed resolution of CSC by a few weeks, but after several months the visual and anatomic outcome is no different than with traditional laser ("hot laser"). Because the outcomes are the same, one needs to consider other factors, such as risk, cost, and convenience, in deciding which treatment to recommend to patients with chronic CSC. Both treatments involve laser therapy. However, PDT involves systemic intravenous administration of a drug (Visudyne) prior to laser therapy. The cost of this drug is not insignificant, and it rarely can trigger some significant adverse effects, including severe chest pain, atrial fibrillation, hypertension, and hypersensitivity reactions. Hence, there does not seem to be at the present time a compelling reason to recommend PDT for CSC.

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Commercially available devices for measuring macular pigment are not precise enough to accurately measure the increase in macular pigment that usually accompanies the use of lutein supplements, according to a new study.

Twenty-four studies have investigated the repeatability of macular pigment optical density (MPOD) measurements using heterochromatic flicker photometry. Of these, 10 studies provided a coefficient of repeatability or data from which the coefficient could be calculated, with a range in values of 0.06 to 0.58. The lowest coefficient of repeatability assessed on naive subjects alone was 0.08.

The coefficient of repeatability is the range that a second measurement can vary from the first purely by chance, not due to changes in the eye. In statistical terms, it is twice the standard deviation of the difference between the two measurements. Only changes greater than the coefficient of repeatability can be assured of being due to actual changes in the eye and not an artifact of the instrument.

These values tell us that, at best, changes greater than 0.08 can be considered clinically significant and at worst, only changes greater than 0.58 can be considered clinically significant.

Six studies have assessed the effect of supplementation with up to 20 mg/day of lutein on MPOD measured using heterochromatic flicker photometry. The mean increase in MPOD ranged from 0.025 to 0.09.

The investigators conclude that available instruments have a low chance of detecting changes in MPOD that are likely to occur following lutein supplementation. They advise caution when considering the use of these instruments for monitoring of MPOD in patients.

WHAT IT MEANS TO YOU: Lutein supplementation will often result in an increase in macular pigment. Increases in macular pigment can improve vision, filter out harmful rays of the sun, and provide antioxidant protection. There are a variety of different ways to measure macular pigment, but all of the devices in this study use heterochromatic flicker photometry, a subjective method that relies upon the patient to make adjustments to the instrument until an endpoint is reached. To some degree, the precision and repeatability of these devices are limited by the observation skills of the patient. Given the limitations of these devices, as highlighted by the current study, there seems to be little value in using them to monitor patients on lutein supplementation.

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Eye doctors can order DNA tests for dozens of diseases, establishing or confirming a diagnosis. Information on testing laboratories and what tests they can perform is available at http://www.genetests.org, a publicly funded medical genetics information resource. Site includes "user manuals" for genetic testing for specific diseases, including many of the genes associated with AMD risk. An international directory of genetic testing laboratories and clinics. There is also a wealth of educational information available about genetic testing and counseling.

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Bausch+Lomb is conducting a voluntary recall of its PreserVision Eye Vitamin AREDS 2 Formula with Omega 3 soft gels, only available within the United States. Bausch+Lomb chose to initiate this recall based on a small number of reports of difficulty swallowing or a choking sensation when taking the soft gel. The voluntary recall is limited only to the United States. The PreserVision Eye Vitamin AREDS 2 Formula with Omega 3 is the only supplement affected in the recall; all other PreserVision and Ocuvite supplements, soft gels and tablets, remain on the market. Bausch+Lomb expects to release an AREDS 2 formulation in a smaller soft gel which will be dosed twice per day, two pills per dose. This immediate redesign is expected to be available to customers by later this year. Consumers who have PreserVision Eye Vitamin AREDS 2 Formula with Omega 3 in their home should call Bausch+Lomb's customer service center for instructions on returning and reimbursement: 1-800-553-5340.

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After 24 months of follow-up, patients treated with intravitreal Avastin (IVB) have superior outcomes compared to patients treated with PDT for myopic CNV (mCNV), according to a study published in the British Journal of Ophthalmology. Patients were divided into Group A, consisting of 12 eyes treated by PDT, and Group B, consisting of 12 eyes treated by 1.25 mg IVB. The visual acuity did not change after PDT but was significantly improved at 12 months and at 24 months after IVB. The central foveal thickness were significantly reduced in both groups at 12 and 24 months. The regions of chorioretinal atrophy were larger in group A than in group B at 12 and 24 months, and their sizes were correlated with visual acuity. The investigators conclude that at 24 months, Avastin is more effective than PDT in treating mCNV. The authors state that enlargement of chorioretinal atrophy might be related to the incomplete visual recovery following PDT.

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The US Food and Drug Administration (FDA) has approved a visual prosthetic device known as an Implantable Miniature Telescope (IMT) to improve vision in patients 75 years and older with stable severe to profound vision impairment caused by bilateral central scotoma associated with end-stage AMD. FDA approval was based on data from a multicenter clinical study of 217 patients with bilateral moderate to profound central vision impairment at a level that constitutes legal blindness. A statement from the American Academy of Ophthalmology said that prior to implantation patients need to receive testing with an external telescope that simulates the effect of an IMT to learn whether vision improvement would be possible. Also, patients need to be fully informed of the risks of the procedure - most importantly the risk of corneal endothelial cell loss which may cause long term problems with corneal clarity. After surgery patients need to undergo rehabilitative vision training with a low vision specialist.

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Improvement in visual acuity is often considered the best indicator of the effectiveness of a treatment in AMD. However, during the course of the disease, the location of the patients' preferred retinal locus (PRL) of fixation may change. This can lead to an unexpected functional improvement, unrelated to treatment. From a database of 1,369 retina patients, 116 patients over 60 years of age when AMD was diagnosed we included in the study. 12 patients experienced an improvement in the visual acuity in one eye without the possibility of improvement due to previous or concurrent treatment in that eye. Over time, these patients had significant improvements in the visual acuity in the weaker eye, characteristically accompanied by a concurrent decrease in visual acuity in the other eye, which initially had better visual acuity. The investigators conclude that improvements in visual acuity can occur solely due to the course of the disease in the other eye and as a result of its impact on binocular fixation characteristics. This study was published in the July 2010 edition of Current Eye Research.

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