Choroidal Thickening and Outer Retinal Alterations in Vitamin A Deficiency: A Case Report

Vitamin A deficiency (VAD) can interfere with visual function and cause severe, irreversible damage to the eye [1, 2]. Xerophthalmia is often associated with anterior segment and corneal findings, such as Bitot’s spots and corneal ulcers, but it can also affect the retina. Nyctalopia is a common symptom, and electroretinogram studies have demonstrated predominantly rod dysfunction already decades ago [3]. Drusenoid deposits in the outer retina have been identified in severe VAD cases [4], and recent studies have also reported alterations in macular and outer retinal thickness [5‒7]. In most cases, retinal changes are reversible, but they may persist in severe VAD despite supplementation [2].

We encountered a young woman with severe VAD and changes to both the outer retina and choroid. While outer retinal thinning corroborates findings from previous studies, this case is also notable for the presence of choroidal thickening.

A 39-year-old woman presented with progressive nyctalopia, mild photophobia, and reduced visual acuity of 20/25 in both eyes over the past 2 years. She had a history of gastric band surgery and biliopancreatic diversion, performed 9 and 3 years ago, respectively. No other significant medical issues were reported. Ophthalmic examination revealed unremarkable anterior segments and normal intraocular pressure. Fundus examination showed subtle changes in the central reflex and a faintly altered perimacular area.

Spectral-domain optical coherence tomography (SD-OCT, Spectralis, Heidelberg Engineering, Germany) revealed significant disturbances in the photoreceptor and retinal pigment epithelium layers, including very discrete drusenoid deposits and the so-called double-carrot sign (Fig. 1a). The total retinal thickness and outer retinal layer thickness were reduced (Fig. 2a), while the choroidal and choriocapillaris layers showed thickening (Fig. 3a). Quantitative measurements of retinal layer thicknesses were obtained using Heidelberg automated segmentation software and are shown in Table 1. Choroid and choriocapillaris thicknesses were measured using the RetinAI Discovery online software (RetinAI AG, Switzerland), an AI-derived tool that automatically segments and measures retinal and choroidal layers and biomarkers.

Autofluorescence imaging revealed a discrete granular pattern in the perifoveal area and slight reduction in the macular hypofluorescent spot. Visual field testing showed a concentrically reduced pattern. Full-field electroretinography (RETIport, Roland Consult, Germany) revealed complete depletion of scotopic responses and mild reduction of photopic responses (Fig. 4).

Laboratory analysis showed severely reduced vitamin A levels in serum (<0.1 µmol/L, reference range: 1.05–2.08 µmol/L). Intramuscular vitamin A supplementation was initiated in an outpatient setting, leading to rapid improvement in symptoms within a few weeks. Retinal imaging, performed 3 months after supplementation, showed complete resolution of both symptoms and retinal structural changes, with restored outer retinal layer thickness (Fig. 1-3b). Monthly intramuscular vitamin A supplementation was continued. The CARE Checklist has been completed by the authors for this case report, attached as online supplementary material (for all online suppl. material, see https://doi.org/10.1159/000544701).

This case emphasizes that vitamin A deficiency can occur despite ongoing oral supplementation, particularly in patients with malabsorption syndromes. Our patient presented with nyctalopia, which is common in VAD, but also with photophobia, a less frequently described symptom. Visual field defects and other functional alterations were consistent with previous reports [5, 8, 9]. Structural changes revealed significant disturbances in the outer retinal layers, particularly the photoreceptor layer and retinal pigment epithelium (RPE). Few drusenoid deposits were observed. The second major finding was thinning of the outer retinal layers, especially the outer nuclear layer (ONL), which is consistent with previous findings, given that the visual cycle is localized in the receptors found in these layers [7].

In addition, the choriocapillaris and choroid were thickened, a novel finding in this context. We hypothesize two possible mechanisms: 1) an increased demand for nutritional supply, mediated through the release of vasoactive or inflammatory substances, leading to increased blood flow and choroidal thickening, or 2) due to thinning of the retinal layers, the choroid may expand to fill the gap between the RPE and sclera. Notably, the total retinal and choroidal thickness was increased before supplementation, which supports the first hypothesis. No circadian influence was noted, as measurements were taken at 3 PM and 11 AM [10]. While hormonal changes and stress have been described to play a role in some pachychoroid spectrum disease such as central serous choroidopathy [11], a large variety of inflammatory and noninflammatory diseases have been identified to present a thickened choroid as well [12, 13]. This relativates the importance and clinical implication of a thickened choroid. However, findings from pachychoroid pigment epitheliopathy [14], also tamoxifen-induced in one case, showed comparable findings to our case, with similar structural alterations, retinal thinning and choroidal thickening [15]. However, larger studies with statistical significance are needed to confirm our finding. Advances in retinal imaging technologies, such as high-resolution OCT and OCT-angiography, may provide additional insights in future studies.

This case underscores the importance of considering vitamin A deficiency, even in patients receiving oral supplementation. We confirm the outer retinal thinning and structural changes previously reported in other cases and introduce choroidal thickening as a potential finding in VAD. Further studies are needed to assess the significance of these choroidal changes.

Ethical approval is not required for this study in accordance with local or national guidelines. Written informed consent was obtained from the patient for publication of the details of their medical case and any accompanying images.

M.S.Z.: Allergan, Bayer, Novartis, Heidelberg Engineering, Boehringer Ingelheim. The following authors have no financial disclosures: D.J., J.-B.L., F.M.H., L.E.B., and J.D.U.

No funding or grant support.

All authors attest that they meet the current ICMJE criteria for Authorship. D.J., J.-B.L.: preparation of manuscript text. F.M.H., J.D.U.: preparation of figures and review. M.S.Z. and L.E.B.: literature review, medical responsibility, and review of the manuscript.

All data generated or analyzed during this study are included in this article. Further inquiries can be directed to the corresponding author.