Citicoline and vision: why it was studied in ophthalmology

Citicoline and vision have been the subject of ophthalmological research primarily because of its role in the cells of the retina and the optic nerve in transmitting nerve signals. Citicoline, also known as CDP-choline, is involved in the exchange of components of cell membranes. On this biochemical basis, scientists began to test whether its additional administration is associated with changes in the performance of the visual system. Most clinical work has been devoted to people with glaucoma, rather than healthy participants who simply want to see better.

Small studies have reported changes in individual electrophysiological parameters, visual fields, and assessments of vision-related quality of life. However, a positive result in one experiment does not necessarily mean that a substance restores vision or affects the course of the disease. Consistent results from high-quality studies are needed to draw conclusions, and this is where the current evidence base has significant limitations.

Why citicoline has interested ophthalmologists

The retina is a nervous tissue. Its ganglion cells transmit information from photoreceptors through complex neural circuits to the optic nerve and then to the brain. Membrane phospholipids are an important part of these cells, and CDP-choline is an intermediate in the biosynthesis of phosphatidylcholine. Therefore, citicoline began to be considered in research models devoted to the functioning of nerve cells of the visual pathway.

The link between membrane turnover and neuronal function is biologically plausible. However, it does not prove that oral citicoline alone will alter retinal function in humans. The mechanisms shown in cellular and experimental models need to be independently validated in clinical trials with appropriate control groups (Prinz et al., 2023).

Why is most of the work devoted to glaucoma?

Glaucoma is associated with progressive damage to the optic nerve and loss of retinal ganglion cells. Clinical trials assess, among other things, changes in visual field, intraocular pressure, and retinal nerve fiber layer thickness. These objective measures allow us to discuss the possible impact of the intervention under study on the visual system—but they do not replace the assessment of long-term consequences.

Researchers have studied different ways to administer citicoline: oral solutions, injectable forms, and eye drops. These methods cannot be considered interchangeable. The results of the drop study do not prove the same effects as the capsules or powder. Similarly, data obtained in patients with glaucoma cannot be automatically transferred to people without ophthalmological disorders.

What clinical studies on citicoline and vision have shown

Individual randomized trials have shown positive signals, but they have varied in their methods of administration, number of participants, and endpoints. Because of these differences, the results should be read in conjunction with the design of each trial and not reduced to a simple claim of visual benefit.

The dosages in this table are provided solely for the purpose of describing the protocols accurately. They are not a dosing regimen or a recommendation for self-administration. It is particularly important that the study by Antón et al. evaluated a combination of two substances, while the study by Rossetti et al. (2020) used drops rather than an oral dietary supplement.

What do visual field changes, PERG and VEP mean?

The abbreviations MD, VFI, PERG, and VEP are often mentioned in literature about citicoline. They describe different aspects of visual function, so improvement in one indicator should not be interpreted as restoration of vision in general.

• MD (mean deviation) is a generalized indicator of the deviation of the light sensitivity of the visual field from the age norm.
• VFI (visual field index) is an index that summarizes the functional state of the visual field.
• PERG — pattern electroretinography, a method of assessing the electrical response of the retina to a visual stimulus.
VEP — visual evoked potentials, indicators of the response of the visual pathways and cerebral cortex.

Electrophysiological changes can be useful for understanding mechanisms and generating new hypotheses. However, for practical conclusions, it is important whether they are accompanied by a sustained clinically meaningful outcome—for example, reproducible preservation of visual function over time.

Why the systematic review did not confirm a conclusive result

In 2023, Prinz et al. summarized 10 clinical trials with 424 patients. When comparing groups, the authors found no statistically significant differences in intraocular pressure, standard visual field index MD 24-2, retinal nerve fiber layer thickness, and PERG amplitude. They concluded that the available data are insufficient to state that citicoline slows the progression of glaucoma.

This does not mean that every positive result from a single trial is false. The question is how consistently it is replicated in independent studies and how much it affects real-world clinical outcomes. Some of the studies had small samples, different control conditions, and different methods of administration. Later studies also need to be evaluated in the context of all previous data, rather than selectively citing the most favorable results.

Has citicoline been studied for vision in healthy people?

The main clinical literature focuses on specific ophthalmological conditions, primarily glaucoma, and does not support the claim that citicoline improves visual acuity, reduces the need for glasses, prevents age-related changes, or compensates for prolonged screen time in individuals without eye disease.

It is also important to distinguish between visual acuity and visual field. A person may retain the ability to read small text but have peripheral visual field impairment. Therefore, even a correctly measured change in one ophthalmological parameter does not necessarily mean an improvement in all aspects of visual function.

What to consider when evaluating such studies

Citicoline was considered an adjunctive intervention in the study protocols, not a replacement for standard ophthalmic care. In particular, participants in the trial with glaucoma continued to receive their prescribed intraocular pressure control medications. Transferring study regimens to the use of dietary supplements alone may be inappropriate and dangerous.

If you have a diagnosed eye condition, visual field changes, or new visual symptoms, you should seek the advice of an ophthalmologist. Pregnant women, lactating women, people with chronic conditions, and those taking medications should consult a physician before taking any dietary supplement. Clinical protocol data does not replace product-specific instructions.

Thus, the ophthalmological interest in citicoline has a clear biochemical basis, but it should not be presented as a substance with a proven ability to improve vision at present. It is scientifically more correct to speak of an investigational compound, the effects of which have been evaluated in different studies using different endpoints.

Frequently asked questions

Why is citicoline being studied in ophthalmology?
It is involved in the exchange of cell membrane components. Researchers are interested in whether processes associated with it can affect measurable functions of the retina and visual pathways.

Is citicoline proven to improve vision?
No, the available clinical data does not support the general claim of improved vision, especially for healthy people.

Why is glaucoma often mentioned in citicoline studies?
Glaucoma involves assessing the function of the optic nerve and changes in the visual field, which is why many clinical studies have been conducted on such patients.

Are there positive research results on citicoline?
Yes, some trials have reported changes in certain parameters. But a systematic review has not confirmed sufficient evidence of slowing glaucoma progression.

Do citicoline eye drops and capsules work the same?
This conclusion is not supported. These are different uses for which the research results need to be considered separately.

What does the PERG score mean in research?
This is an electrophysiological method of assessing retinal response. A change in PERG does not in itself mean restoration of visual acuity.

Can citicoline replace medications prescribed by an ophthalmologist?
No. The additional interventions being studied are not a substitute for diagnosis, monitoring, and doctor-prescribed care.

Sources

• Prinz J. et al. (2023). Efficacy of citicoline as a supplement in glaucoma patients: A systematic review. PLOS ONE. PubMed.
• Rossetti L. et al. (2020). Can Treatment With Citicoline Eyedrops Reduce Progression in Glaucoma? The Results of a Randomized Placebo-controlled Clinical Trial. Journal of Glaucoma. PubMed.
• Antón A. et al. (2022). The Effect of Oral Citicoline and Docosahexaenoic Acid on the Visual Field of Patients with Glaucoma: A Randomized Trial. Life. PubMed.
• Rossetti L. et al. (2023). The effect of citicoline oral solution on quality of life in patients with glaucoma: the results of an international, multicenter, randomized, placebo-controlled cross-over trial. Graefe's Archive for Clinical and Experimental Ophthalmology. PubMed.

Dietary supplement. Not a medicine. Consult a doctor before use.