Early Detection of Retinal Dysfunction May Help Diagnosis
Early detection of abnormalities to the eye’s retina and loss of visual acuity may help diagnose neuronal ceroid lipofuscinosis (NCL), aka Batten disease, and improve patient care, Brazilian researchers suggest.
For several neurodegenerative disorders that have symptom onset during early infancy is not uncommon for the children to develop eye and vision problems. Because of that, for many of these illnesses, diagnosis, treatment, and rehabilitation programs include visual evaluations.
NCL comprises the most common pediatric neurodegenerative disorders. Eye symptoms in these patients are a common first sign of disease. Progressive degeneration of the retina – the light sensitive inside layer of the eye that can detect visual stimulus and sends images to your brain – is found to be an early NCL-related event. However, in many cases the structures of the eye may appear normal or present some nonspecific abnormalities.
In the study “Retinal function in patients with the neuronal ceroid lipofuscinosis phenotype,” which was published in the Arquivos Brasileiros de Oftalmologia, a team of researchers determined the characteristics of clinical and retinal dysfunction in patients with the NCL.
The team analyzed the ophthalmologic disease-related presentations in NCL in 15 children from 1 to 12 years old. All the patients were examined in the Department of Ophthalmology and Visual Sciences of the School of Medicine at the Federal University of São Paul, Brazil, from July 2001 to December 2008.
The team grouped the patients according to age of symptoms onset and clinical manifestations. Five patients had Jansky-Bielschowsky disease (JB) with epilepsy and neuro psycho-motor involution (NPMI), five children had infantile NCL (INCL) with epilepsy and/or NPMI, and the remaining five patients were classified as juvenile NCL (JNCL), also known as Batten-Spielmeyer-Vogt-Sjogren disease, having epilepsy and/or NPMI with reduced visual acuity.
The most frequent visual symptom, experienced by 66.7 percent of the patients, was progressive visual acuity loss. About 33.3 percent of patients had no visual symptoms. Visual loss was associated with other neurologic features in nine patients, and one patient reported only visual loss as the initial complaint.
Evaluation of the retina revealed that two patients with JB diseases had normal structure, but mild visual impairment due to cone-rod dysfunction — progressive degeneration of the light-sensitive cells. Two other JB patients who had worse visual acuity (they could not fixate or follow objects or light) had more structural abnormalities with severe retinal dysfunction. The last JB case had degeneration of the ocular nerve cells and cone-rod dysfunction.
“Generally, those with the lowest visual acuity had more severe ophthalmic changes,” the researchers reported.
All five INCL patients had normal structures, but abnormal retinal findings. Three patients had cone-rod dysfunction, and two exhibited diffuse retinal dysfunction. However, the researchers did not find any correlation between visual acuity and retina dysfunction in these patients.
Assessment of the five JNCL patients revealed they all had structural changes with diffuse retinal dysfunction.
Overall, these results showed that at initial stages of the disease it is common for NCL patients not to have visual symptoms. However, as the disease progresses it is likely patients will experience visual loss.
The researchers also found that, even in the absence of visual symptoms, patients are already likely to have some degree of retinal dysfunction. The analysis findings suggested “a more pronounced impairment of rod function [the cells that detect image at low light levels] and relative preservation of cone function [the cells that detect color] among this series of patients with NCL,” the team stated.
“Despite research into experimental therapies, NCL is currently untreatable, and early diagnosis is needed to implement appropriate counseling and support,” the researchers said. The team believes that early detection of retinal abnormalities and visual acuity loss due to NCL “may be useful for NCL diagnosis, particularly in patients who do not have access to genotyping [genetic assessment]”.