Study identifies eye changes in Fabry that could affect vision
Abnormalities found in cornea that affect way it focuses light onto retina
Changes in the cornea are found in the eyes of people with Fabry disease who have a common disease symptom called corneal verticillata, and these alterations could affect vision quality, a study has found.
Specifically, patients tend to have more abnormalities or aberrations in the cornea that affect the way it focuses light onto the retina. Researchers found higher-order aberrations (HOA), which is a complex type of optical imperfection that can influence vision quality, were significantly higher in Fabry patients with corneal verticillata than in healthy volunteers.
“According to classical knowledge, cornea verticillata does not decrease visual acuity,” researchers wrote. “However, the increase in HOA caused by cornea verticillata may impair visual quality.”
The findings warrant more research on how the cornea and visual acuity are impacted in Fabry, researchers noted.
The study, “Investigation of topographic, aberrometric, and endothelial cell features of the cornea in Fabry disease,” was published in International Ophthalmology.
Eye-related abnormalities often earliest observable signs of Fabry
Fabry disease is a multisystemic condition where the fatty molecule globotriaosylceramide (Gb3) accumulates in various tissues, leading to progressive organ damage and a wide range of symptoms.
Among the places Gb3 builds up are the eyes, and eye-related abnormalities are often among the earliest observable signs of the disease. A routine eye exam can sometimes help to diagnose the rare condition.
“Early diagnosis and treatment of FD [Fabry disease] are crucial for prevention of organ failure and irreversible tissue damage,” the researchers wrote. ” Ocular findings related to FD … are usually early signs of the disease and play a significant role in establishing the diagnosis.”
About three-quarters of patients experience corneal verticillata, a starburst-like pattern of cloudy areas (opacities) on the cornea, or the surface layer of the eye. Other ocular signs of the disease can include opacities in the eye’s lens, and twisted blood vessels in the eye (vascular tortuosity).
In the recent study, the scientists sought to further examine ocular characteristics of Fabry, particularly looking at the cornea, which helps protect the eye and focus incoming light onto the retina to allow for clear vision.
A total of 21 people with Fabry and 41 healthy volunteers participated, with one eye examined from each person. Most with Fabry (17 of 21 people) were receiving enzyme replacement therapy.
Advanced techniques were used to capture features of the cornea including its curvature, thickness, elevation, and cellular features.
Among people with Fabry, the most commonly observed eye changes were vascular tortuosity in parts of the eye including the retina (85.7%) or conjunctiva (mucus membrane that protects the eyes, 80.9%), followed by abnormal ballooning of the blood vessel walls in the conjunctiva (61.9%), corneal verticillata (52.3%), and lens opacities (19%).
Eye changes more common in men with Fabry
These changes were all observed more commonly in men than in women, consistent with known sex differences in disease severity.
The thickness of the center of the cornea was significantly smaller in people with Fabry than in healthy volunteers, as was its thickness at its thinnest point.
“This is the first study to investigate the impact of cornea verticillata on ocular aberrations in FD,” the researchers wrote. “The findings have shown a remarkable increase in HOA values in eyes with cornea verticillata.”
However, the exact effects of HOA on aspects of vision weren’t studied in detail here. The scientists indicated that more research will be needed to fully understand the ocular symptoms of Fabry, and to clarify how the condition impacts visual abilities.
That will be especially important since this study involved relatively few participants and most of them were already being treated with therapies that could ease eye-related problems.
“These findings …can pave the way for more extensive multicentre studies in the future,” the scientists wrote, noting such studies “will contribute to our understanding of the mechanism underlying the anatomical and optical changes induced by FD in the cornea.”
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