Stargardt’s disease is an hereditary form of macular degeneration characterized by central vision loss but preserved peripheral vision, caused by mutations in the ABCA4 gene.

Oral therapy has proven successful at helping those living with Stargardt’s disease to make improvements, and companies such as Nightstar Therapeutics Inc and Lin Bioscience are working on treatments for this condition.

What is Stargardt’s Disease?

Stargardt disease is a genetic eye disorder that leads to gradual vision loss by gradually building up fatty deposits under the retina’s macula (the small area responsible for sharp, central vision). A faulty gene known as ABCA4 typically provides instructions for making a protein that effectively cleans out these substances from retina cells; in people suffering from Stargardt’s disease however, mutation prevents this protein from working properly, leading to yellowish clumps of fatty deposits accumulating under their retina that destroy light-sensitive cells that cause central vision to decline over time.

Stargardt’s disease may result in improved visual acuity and color vision following treatment with topical cholinergic medications, particularly among late-onset subtypes where progression can be more rapid than generalized forms. Tracking this progression with tests such as Amsler Grid or visual acuity testing. Fluorescein angiography also allows monitoring for leaky blood vessels in the retina.

Stargardt’s may not be curable, but you can slow its progress by visiting an ophthalmologist regularly and eating a diet rich in fruits and vegetables. When outside, wear quality sunglasses with wide-brimmed hats to shield your eyes from harsh sunlight rays; avoid glaring lights; contact local agencies for the blind for information on low vision aids; wear quality sunglasses indoors to shield from bright lights that might damage them as much as possible.

Laser treatment may temporarily stop blood vessels leaking in the retina from leaking, though this does not restore vision or stop its progression. Therefore, early diagnosis is critical so patients can be educated about and prepared to deal with the slow loss of vision associated with AMD with geographic atrophy; as well as avoid misdiagnoses of dry AMD as dry AMD without geographic atrophy that could result in unnecessary treatments that don’t address root cause of the condition.

Symptoms

Stargardt’s Disease is an inherited form of macular degeneration, usually appearing during childhood or adolescence and marked by yellowish-round spots on retinal pigment epithelium (RPE) that appear as “beaten-bronze” spots on fundus autofluorescence (FAF). Over time, central vision progressively worsens until legal blindness eventually sets in; most cases of Stargardt’s are autosomal recessive due to mutations in ABCA4 gene that transport vitamin A through photoreceptor cells of eye cells.

Gene mutations cause lipofuscin to accumulate in the RPE and ultimately damage light-sensitive cone cells in the macula, eventually leading to progressive central vision loss over time. First fine detail vision disappears followed by color vision loss before driving and reading are no longer possible.

Ophthalmology recently published a case study to demonstrate the success of treating Stargardt’s disease with echothiophate iodide as a topical cholinergic medication. One patient saw their best corrected visual acuity improve from counting fingers to 20/100 after receiving this drug treatment; other patients experienced less dramatic but still significant improvements in vision.

Once her ophthalmologist discovered an ABCA4 mutation causing her specific form of the disease, they prescribed her this drug (0.015%) at low dosage levels; she experienced immediate improvement which continued over a 15 year follow up period.

This patient’s experience echoes previous studies which demonstrated the success of treatment; however, it should be noted that not all Stargardt’s disease patients will experience similar levels of vision recovery. For example, those initially diagnosed with VAs of 20/400 or lower did not necessarily improve to 20/20 vision within two years while those diagnosed at higher VAs (e.g. 20/100) saw only moderate improvements. Still, these findings provide hope to those living with this condition and should serve as motivation to seek diagnosis early; visit the National Institutes of Health website which provides an in-depth overview of inherited eye diseases. For more information and resources visit National Institutes of Health website who has an in depth overview of many inherited eye diseases.

Diagnosis

Stargardt’s disease is a form of macular degeneration that leads to central vision loss, caused by variations in an ABCA4 gene. This gene normally produces protein that aids vitamin A use by the body; in people suffering from Stargardt’s, however, this protein does not function correctly and too much fatty material accumulates on the retina (light-processing tissue lining the inside of eye), ultimately leading to disease symptoms and leading to decreased central vision.

Diseased eyes typically first manifest themselves during childhood or early adolescence when central scotomas and loss of color perception become evident. Over time, symptoms worsen as cone photoreceptor cells in the retina deteriorate further, until eventually the central part of retina becomes nonfunctional and person becomes legally blind.

Stargardt’s macular degeneration is one of the slowest-progressing forms of macular degeneration; patients typically do not become legally blind until their 40s or 50s. Diagnosis involves conducting a comprehensive eye exam with an ocular fundus examination; genetic tests may also be administered to confirm whether someone has it.

Fluorescein angiography and optical coherence tomography can also help diagnose this disease, showing dark areas called RPE detachment in the retina. A fundus autofluorescence test can identify retinal flecks; newer ones will appear hyperautofluorescent while older ones become hypoautofluorescent over time.

These tests can assist physicians in deciding the appropriate course of action for a patient. They may suggest trying different treatments or even taking part in clinical trials to slow disease progression.

As the most prevalent juvenile macular dystrophy, Stargardt’s can be difficult to treat. But researchers are exploring potential strategies to slow or stop its progress, with one study published in Ophthalmology showing improvement for one of Stargardt’s patients given echothiophate iodide treatment after five years; this improvement continued over this time frame indicating its potential use against Stargardt’s disease and similar degenerations.

Treatments

Stargardt’s disease causes progressive vision loss over time. This hereditary condition impacts part of the retina called the macula that contains high concentrations of light sensing cells such as rods and cones that over time become degenerate, eventually leading to legal blindness and decreased central vision. Lipofuscin deposits known as lipofuscin accumulate within retinal pigment epithelium (RPE).

Scientists have successfully isolated the gene mutation that causes Stargardt’s and have devised experimental treatments, including drugs that reduce toxic vitamin A aggregate formation, an inhibitory treatment to the complement system activation process and stem cell treatments – however none of this research has passed clinical trials yet.

Researchers published in Ophthalmology a case study showing early and sustained improvements in visual acuity and color vision for a Stargardt disease patient treated with echothiophate iodide, a topical treatment known to increase endogenous acetylcholine production – essential in transmitting light signals from photoreceptors to brain photoreceptors for vision transmission and thus perception.

Prior to receiving treatment, this subject suffered from Stargardt disease with best corrected visual acuity of 0.015 logMAR in each eye. By the end of 24 weeks’ study period, both eyes’ BCVA had improved dramatically to reach an overall score of 0.063 logMAR; results were validated through fundus autofluorescence imaging, ocular and systemic safety evaluations, Octopus visual field perimetry testing and multi-luminance shape discrimination testing.

The improvement of vision can be attributed to the drug’s ability to increase acetylcholine in the eye, with an increase correlated to decreased accumulation of lipid deposits at RPE in the eye. Furthermore, inhibition of enzyme acetylcholinesterase helps preserve acetylcholine for prolonged use in retinal health disorders like glaucoma and strabismus treatment; until recently cholinergic medications had only been used as part of treatment plans for these two conditions alone; recent research suggests their use can treat various retinal conditions.