Patient using serum drops 'feels eyes again'

While most cases of dry eye disease respond well to established treatments, there is a subset with severe dry eye that may need other options. Serum eye drops have been successfully used for decades for conditions including persistent epithelial defects and neurotrophic keratopathy. Increasingly, they are also being used in cases of severe dry eye, particularly Sjögren’s disease.

Serum is derived from human blood, with the cellular components removed and the remaining serum diluted with saline. No preservatives are added, so it is supplied frozen, in vials. The patient thaws and uses one vial per day, using up to six drops per eye, or as much as they can get out of each vial.

Serum closely mimics the pH and biochemical composition of tears, plus it is rich in platelets and platelet-derived growth factors and contains vitamins A, E and fibronectin. These inhibit apoptosis, improve cell growth and migration, promote epithelial healing and reduce ocular surface inflammation. After all, every cell in our body is bathed in serum to keep it healthy and viable.

There are two main types of serum eye drops: autologous, produced from the patient’s own blood; and allogeneic, from healthy, screened type-AB donors who have neither anti-A nor anti-B antibodies in their serum. Both autologous and allogeneic serum drops are very safe with very few (if any) side effects.

While autologous drops have long been the mainstay, they aren’t always feasible – particularly in patients with poor venous access, systemic health issues or blood-borne infections. In 2012, New Zealand’s Dr Malcolm McKellar and Dr Krishna Badami published an allogeneic serum eye drop protocol to make allogeneic serum an option. Allogeneic drops are logistically easier to manage and can be dispensed about a week after the request, whereas autologous drops have a minimum three-week processing time. As a result, there is a move internationally towards using allogeneic drops.

Serum Eyedrops Figs — Fig 1. (A) The design of the serum eye drop vial allows for simultaneous sterile filling of multiple vials then(B) the connecting tubing is sealed off for individual use. Credit: NZ Blood Service

New Zealand Blood Service has vast experience in producing blood products and has an excellent process for supplying serum eye drops. It collects, produces and dispenses these, at no charge to the patient, on a direct request and prescription from an ophthalmologist. It is important to point out the drops are expensive to produce, costing well over $6,000 per patient per year, so serum drops should be considered a specific treatment for a defined period of time to help heal and restore the ocular surface. While they are preservative-free, they should not be regarded as a substitute for non-preserved artificial tears, except as a last resort. Careful stewardship of this service is important to prevent unnecessary cost, so patients are seen regularly to ensure the serum remains better for the patient than conventional treatments and to monitor the condition for improvement in case the drops are no longer necessary.

While there are relatively few studies comparing autologous and allogeneic serum, clinical experience suggests allogeneic serum drops are as safe and effective as autologous serum. All donors are carefully screened, with no known transmission of disease to date and the immunological risks appear very small.

It can be difficult to predict which patients will benefit significantly from serum eye drops for DED, but it’s a good rule of thumb to try all conventional treatments first. Because the drops need to remain frozen until use and they can be difficult to open and use, the patient will need some commitment (and dexterity) and they will usually need to continue their other dry-eye treatments. It’s always important to explain that the drops promote healing – they are not a magic eye drop.

I’ve had extensive experience with both serum eye drops and conventional treatments for many patients with ocular surface disease and dry eyes. In some patients with significant, painful and visually disabling dry eye, autologous and allogeneic serum drops have provided a marked improvement in comfort and corneal health when nothing else worked. With persistence and time, they can allow the ocular surface to heal and sometimes represent a transformative treatment.

To conclude, I offer a recent quote from a patient who had tried everything before using serum drops, including bandage contact lenses. “I began using the serum eye drops and for the first time in a long time I can truly feel my eyes again. It’s the first time I have felt hopeful about my eyes healing.”