research in practice

Breaking Tradition with PED Therapy

Autologous serum and SH contact lenses shown effective.

Mile Brujic, O.D., Crystal Brimer, O.D.

Persistent Epithelial Defects (PED) are typically defined as non-infectious epithelial breaks that do not heal as expected with conventional measures. Traditional treatments have included copious lubrication with artificial tears, topical antibiotics, steroids and bandage contact lenses. The potential complications of PEDs include microbial keratitis, scarring and even perforation of the cornea; all of which can be devastating to the patient and their vision.¹ PEDs can last more than a year and require surgical intervention, such as amnionic membrane grafts. And even surgery is not always successful.

The good news: Autologous serum eye drops have been shown more successful than conventional treatments with artificial tears in healing PEDs. Specifically, the autologous serum contains elements critical for epithelial cell proliferation and migration, including several growth factors and proteins with antimicrobial properties.¹

Current research shows successful treatment outcomes with the use of autologous serum eye drops and silicone hydrogel (SH) therapeutic contact lenses as a course of therapy for PED.²

The supporting research

One study on autologous serum eye drops and SH contact lenses included eight patients who had PEDs of various etiologies, each lasting 30-to-240 days with a mean duration of 90±81.76 days.² Three of the patients had been treated with SH therapeutic contact lenses, and the remaining five had been treated with autologous serum alone. All were unsuccessful in obtaining resolution of their PEDs.

In this study, each patient was fit with a SH therapeutic contact lens and instructed to insert one drop of 50% autologous serum into the affected eye q2h during waking hours.

Following this treatment protocol, each patient experienced full resolution after seven-to-20 days, with a mean recovery time of 11.8±4.9 days. None of the patients experienced complications from the contact lens wear, and the lenses remained deposit free throughout the treatment's course.

In this study, the autologous serum was diluted with sodium hyaluronate eye drops, instead of saline, in order to bind more water and provide added hydration to the ocular surface, as well as aid in epithelial cell proliferation and migration. One patient experienced a PED recurrence at two months, but had successful resolution by repeating the previous treatment plan.

This study is somewhat limited because it does not disclose how long the patients were followed without recurrence. That said, depending on the underlying disease, autologous serum drops may be more of a supportive treatment than a curative one.

Previous studies on this topic examined using autologous serum alone or with hydrogel therapeutic contact lenses to treat PEDs. When 50% autologous serum was used alone, 23 of 25 eyes healed in a median time of 13.9 weeks, ranging from 0.29 weeks to 52 weeks.¹ Two of the 25 eyes were referred for amnionic membrane grafts.

Here, we see a radical difference in healing time compared with the outcome in which SH therapeutic contact lenses together with the 50% autologous serum were used.

When 20% autologous serum was used eight times per day, in combination with a hydrogel therapeutic contact lens, five of the six patients healed in 14.2±8.9 days. One patient healed in 90 days.³ However, substantial deposition on three of the six hydrogel lenses was noted, and this caused considerable lens opacification.

What this means for patient care

Immediately incorporating a treatment protocol of autologous serum eye drops q2h during waking hours, coupled with a SH therapeutic contact lens may have an enormous beneficial effect on the patient's life by dramatically reducing the potential severity and duration of their PED.

It makes sense that compromised corneas have an increased oxygen demand. Using a SH contact lens provides extra oxygen, which may speed the re-epithelialization process. The SH contact lenses also remained deposit free throughout the course of therapy, which allows for improved wettability, patient comfort and vision.²

It is not yet known whether using the 50% autologous serum is more beneficial than the 20% concentration. However, patients prefer the 50% concentration due to the soothing effect provided by its higher viscosity.¹ Conversely, the 100% concentration would cause double the financial burden and discomfort, as the patient would have twice the volume of blood drawn.

Even if the patient has an underlying disease, such as neurotrophic keratitis, that induces a PED recurrence, there is substantial peace of mind in having a treatment plan that radically shortens the potential duration of the PED. Considering that PEDs can easily persist for several months, the ability to prevent someone from enduring long-lasting pain and blur is life-altering for the patient and certainly rewarding for the practitioner.

Real world application

Now, instead of delaying the resolution of a PED by extending the duration of conventional measures, we may have a solid treatment course that is likely to preclude the patient from weeks or months of discomfort and morbidity. Combining the use of 50% autologous serum drops q2h during waking hours with a SH bandage contact lens has been shown as safe and effective in quickly resolving PEDs.

The efficacy of autologous serum eye drops (20% to 100% concentration) has been documented for many ocular surface diseases, including keratoconjunctivitis sicca, superior limbal keratoconjunctivitis and recurrent erosion syndrome, in addition to PEDs.⁴ Now, realizing that the efficacy of autologous serum is greatly enhanced when combined with an SH therapeutic contact lens, you, the optometrist, may consider using this course of therapy to treat these other non-infectious persistent corneal conditions as well.

It has even been suggested that while waiting for the formulation of autologous serum eye drops, it might be feasible to have the patient prick their finger and insert a drop of their own blood into the affected eye.⁵ In extreme cases, this course of action may be reasonable in order to deliver immediate epitheliotropic and antimicrobial components while waiting for the lengthy formulation process. It is certainly a prospect that warrants further investigation. OM

1. Jeng BH. and Dupps WJ Jr. Autologous serum 50% eyedrops in the treatment of persistent corneal epithelial defects. Cornea. 2009 Dec; 28(10):1104–8.
2. Choi JA. and Chung SH. Combined application of autologous serum eye drops and silicone hydrogel lenses for the treatment of persistent epithelial defects. Eye Contact Lens. 2011 Nov;37(6):370–3.
3. Schrader S, Wedel T, Moll R, Geerling G. Combination of serum eye drops with hydrogel bandage contact lenses in the treatment of persis tent epithelial defects. Graefe's Arch Clin Exp Ophthalmol. 2006 Oct;244(10):1345–9.
4. Wilczynski M. The use of autologous serum in the treatment of the ocular surface diseases. Klin Oczna. 2009;111(10-12): 363-8.
5. Sharma A., Sharma BA, Moore J, Nolan M. Simple finger prick fresh blood technique for use on the ocular surface. Contact Lens Anterior Eye. 2011 Feb; 34(1):49.