Ocular neuropathic pain linked to vitamin B12 deficiency

27.07.2019

This case report brings to light a potentially under-diagnosed cause of ocular neuropathic pain - vitamin B12 deficiency. A 28-year-old Indian man who had uneventful LASIK 5 years earlier develops severe burning pain, irritation and foreign body sensation in both eyes during the previous year. Ocular exams showed some bilateral punctate epithelial erosions and a rapid tear breakup time, but was otherwise unremarkable. 

Treatment with preservative-free artificial tears and 0.05% topical cyclosporine failed to alleviate symptoms.Blood tests showed low levels of serum vitamin B12 at 90 pg/mL (reference range, 236-944 pg/mL). The patient was prescribed 1000μg intramuscular daily for 1 week followed by 1000μg monthly oral supplements for 6 months, in addition to topical therapy. Within 3 weeks, the patient's symptoms were completely relieved and all ocular surface disease parameters improved. At last follow-up, the patient was symptom-free and stopped using all topical medication.

Patients with ocular neuropathic pain often experience symptoms out-of-proportion to findings and often do not respond to topical therapy. In the United States, vitamin B12 deficiency may be observed in patients with pernicious anemia, prior bariatric surgery, celiac disease or Crohn's disease and immune system disorders including Graves' disease and lupus. It may also occur in vegans or vegetarians who are not consuming enough eggs or dairy products.As a result, it is important to take a detailed history, including dietary history, when evaluating patients with more challenging ocular surface issues. 

The authors conclude that vitamin B12 deficiency should be considered in the differential diagnosis of ocular neuropathic pain and dry eye in patients presenting with recalcitrant ocular neuropathic pain.

Written By: Jennifer Li, MDCornea/External Disease

Management of Ocular Neuropathic PainWith Vitamin B12Supplements: A Case Report

Shetty, Rohit DNB, FRCS; Deshpande, Kalyani MS, FICO; Ghosh, Arkasubhra PhD; Sethu, Swaminathan BDS, MSc, PhD

Purpose: To report the case of a 28-year-old patient with persistent bilateral burning pain and foreign body sensation in both eyes for the past 1 year. The patient showed a poor response to 0.05% cyclosporine eye drops and frequent instillations of artificial tears. Ocular examination showed few superficial punctate epithelial defects, well-positioned laser in situ keratomileusis (performed 5 years ago with symptomless recovery) flaps, and clear interfaces bilaterally, with a tear film breakup time of 7 and 8 seconds in the right and left eyes, respectively. The results of Schirmer tests, confocal microscopy, corneal esthesiometry, and meibography were normal for both eyes. The patient was incidentally diagnosed with vitamin B12deficiency, with a serum vitamin B12value of 90 pg/mL (reference range, 236-911 pg/mL), during routine laboratory tests. In view of weak correlation between signs and symptoms, a putative diagnosis of ocular neuropathic painsecondary to vitamin B12deficiency was made.

Result: The patient was treated with parenteral vitamin B12, and topical therapy was continued without any changes. The patient experienced dramatic improvement with a decrease in symptoms within 3 weeks of administering vitamin B12supplements and was symptom-free in the absence of any topical medication 6 months after treatment.

Conclusions: Vitamin B12deficiency, although common in India, has not been reported to be associated with ocular symptoms, including pain and mimicking those seen in severe dry eye. Vitamin B12deficiency should be considered in the differential diagnosis of ocular neuropathic painand dry eye in patients presenting with recalcitrant ocular neuropathic pain.