September 2020

CORNEA

Finger-prick autologous blood to treat the eye?


by Maxine Lipner Contributing Writer

Patients with persistent corneal epithelial defects who might benefit from autologous serum eye drops could have another option at their fingertips—literally. A recent study showed that a finger prick of blood healed at least 60% of persistent epithelial defect cases within 1 month, according to Anant Sharma, MD.1
There are several reasons why a simple finger prick might be an attractive alternative to autologous serum tears, which involves processing the patient’s own blood into a serum. These include immediate access, cost, or patients may be too unwell to give blood or don’t have easy access to blood banks, Dr. Sharma noted. “Also, some people don’t want to travel to or find it inconvenient to give blood regularly because this is done approximately every 3 months,” he said.
Dr. Sharma came up with the idea for the alternative finger-prick approach while thinking about how to better deal with patients unable to receive serum. “I thought, I’ll use blood alone because serum is made from clotted blood, which releases most of the growth factors from the platelets.”
With this approach, the patient uses a device to prick their finger, similarly to how a diabetic patient would check glucose levels. They then touch their eye with the drop of blood, Dr. Sharma explained. “A drop of blood is more than enough for the tear film,” he said, adding that the actual volume of the precorneal tear film is about 7 µL. Blood itself is a very complex solution. “The white cells are talking to the platelets, and the red blood cells aren’t just passive oxygen-givers; they secrete growth factors themselves,” Dr. Sharma said. These platelets, if used for treatment, probably adhere to the inflamed surface of the eye or ulcer, he explained, adding that the blood gets stimulated either by the prick itself or on the eye to act as a healing agent.
In the study, 10 patients with persistent epithelial defects (diabetic neurotrophic keratopathy, herpetic keratitis, post-penetrating keratoplasty, keratoconjunctivitis sicca, post-radiotherapy, and neuropathic ulcer) who were unsuccessful with conventional treatment (average duration of ulcer was 259 days) were switched to the finger-prick blood approach. They self-treated 4 times a day for 28 days. Investigators determined that the defects healed completely in six of the 10 patients. In one case, the ulcer was reduced by half at the end of the 28 days, Dr. Sharma reported, adding that three of the remaining patients had incomplete follow-up data.
In addition to utility for persistent epithelial defects, the finger-prick treatment has been studied for dry eye syndrome. In one study,2 29 eyes of 16 patients had a drop of blood instilled in the lower fornix 4 times a day for 8 weeks. “Virtually all 16 benefited in symptoms and signs dramatically,” Dr. Sharma said. At 8 weeks, there was a mean improvement in corneal staining from 3.31 to 2.07, tear breakup time went from 5 seconds to 7.8 seconds, and the ocular surface index improved from 39.72 to 44.67. Visual acuity also improved from 0.08 logMAR to 0.01, Dr. Sharma said.
For severe aqueous dry eye patients, physicians should try conventional treatment but could consider the finger-prick technique, Dr. Sharma said. “None of the other drops come close to what’s in the blood,” Dr. Sharma said. “Restasis [cyclosporine, Allergan], for example, is an anti-inflammatory immunomodulating agent and even that can take 4–8 weeks to start working.” With the finger-prick technique, more than 50% of patients benefited within 3 days, he said.
In Dr. Sharma’s view, the finger-prick technique could be applicable to all conditions where serum is used, including recurrent erosions. “We have had some positive results in some cases when we started them on finger- prick autologous blood for recurrent erosion,” he said. “We also want to use it in corneal infections.” He pointed out that the blood has white cells and antibodies that should make it effective here. Dr. Sharma hopes to initiate a trial on this by next year.

About the doctor

Anant Sharma, MD

Consultant ophthalmologist
Moorfields Eye Centre
Bedford Hospital
London, U.K.

References

1. Balal S, et al. Finger-prick autologous blood in the treatment of persistent corneal epithelial defects. Cornea. 2020;39:594–597.
2. Than J, et al. Fingerprick autologous blood: a novel treatment for dry eye syndrome. Eye (Lond). 2017;31:1655–1663.

Relevant disclosures
Sharma
: None

Contact
Sharma: asharma263@hotmail.com

Finger-prick autologous blood to treat the eye? Finger-prick autologous blood to treat the eye?
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