Experts Emphasize Limitations of OCT in Neuro-Ophthalmology

Optical Coherence Tomography (OCT) is a critical tool in diagnosing optic nerve diseases and monitoring their progression. However, experts caution that it should not be used as a standalone method in neuro-ophthalmology. This insight was shared by Prof. Dr. med. Wolf Lagrèze during the 2nd International Glaucoma Symposium held in Mainz, Germany on January 31, 2024.

In his address, Lagrèze outlined both the strengths and limitations of OCT in diagnosing conditions affecting the optic nerve. He emphasized the necessity of integrating OCT findings with other diagnostic methods, including fundus examination, visual field testing, pupillary assessment, and comprehensive patient history.

While OCT is adept at differentiating various optic nerve conditions and tracking disease progression—particularly in cases of glaucoma—Lagrèze noted that seasoned clinicians can often detect glaucomatous damage using traditional examination techniques. The technology becomes particularly valuable when distinguishing glaucoma from conditions such as optic disc drusen, where enhanced depth imaging allows for a closer inspection of deeper structures within the optic nerve head.

Despite these advantages, Lagrèze pointed out that OCT does not currently provide specific biomarkers for significant neurological disorders like Alzheimer’s disease or Multiple sclerosis. Although researchers are investigating potential diagnostic patterns, he stated that it remains impossible to diagnose such conditions based solely on OCT results.

The technology has shown promise in identifying minor papilledema, a condition characterized by swelling of the optic disc due to increased intracranial pressure. Clinicians analyze patterns such as the relationship between ganglion cell loss and axonal swelling to gain insights into optic nerve involvement.

However, Lagrèze stressed that OCT images deliver primarily black-and-white structural data, contrasting with traditional fundus examinations, which provide detailed color information. Advanced imaging techniques like OCT angiography (OCT-A) have improved the visualization of microvasculature, yet they still require careful clinical interpretation.

He also raised concerns about the risks of misinterpretation, especially when non-ophthalmologists rely exclusively on OCT parameters. Following updates to the McDonald Criteria for diagnosing multiple sclerosis, changes in the optic nerve are now included as indicators of the disease. Lagrèze warned that reliance on measurements such as inter-eye differences in nerve fibre layers could lead to incorrect diagnoses if other factors like patient history and refractive errors are overlooked.

Collaboration between neurologists and ophthalmologists is critical for accurate interpretation of OCT findings. Looking to the future, Lagrèze suggested that integrating OCT with Artificial Intelligence could enhance early disease detection. AI systems can analyze large datasets and uncover subtle patterns that might elude clinicians, potentially improving the early diagnosis of both neurological and ocular diseases.

While AI-assisted imaging may increase sensitivity in detecting diseases, Lagrèze cautioned that maintaining diagnostic specificity is essential to prevent false diagnoses, which could have severe consequences for patients. He concluded by stating that OCT, now nearly three decades old, continues to evolve. Its role in both ophthalmology and neurology could become increasingly significant, provided it is utilized carefully alongside thorough clinical evaluations.