EDTA chelation for calcific band keratopathy: is potassium the new sodium?

Session Details

Session Title: Presented Poster Session: Cornea: Medical

Venue: Poster Village: Pod 2

First Author: : H.Bobat UK

Co Author(s): :    A. Jonas   A. Shinton   N. Mujtaba   M. Rashid              

Abstract Details

Purpose:

Disodium ethylenediaminetetraacetic acid (Na-EDTA) is the most commonly used chelating agent in the surgical treatment of calcific band keratopathy (CBK), but in the UK is available only as a preserved solution or made-to-order at significant cost. Dipotassium EDTA (K2-EDTA), however, is widely available from blood collection tubes, where it acts as an anticoagulant. What is more, the mechanism of action of K2-EDTA means it has greater activity as a chelating agent than Na-EDTA. We describe early findings using K2-EDTA in 6 eyes with symptomatic CBK and consider its use as a more effective alternative.

Setting:

Royal Bournemouth and Christchurch Hospitals NHS Foundation Trust, Dorset, UK.

Methods:

6 eyes of 5 patients underwent K2-EDTA chelation for symptomatic CBK. 2mL of sterile water was transferred between six blood collection tubes, each containing 7.2mg K2-EDTA. Following corneal epithelial delamination with 20% ethanol, and removal of large calcium deposits with a blade, a surgical sponge soaked in the K2-EDTA solution was applied to the cornea and gently agitated until all diffuse deposits were removed. The eye was irrigated with saline, chloramphenicol drops were instilled and a bandage contact lens was inserted.

Results:

K2-EDTA was easily prepared by the surgeon in theatre. In all patients, K2-EDTA enabled complete removal of calcium deposits within approximately 5 minutes of application, and appeared more effective than Na-EDTA in its ability to sequester calcium from the corneal surface. Follow-up thus far has demonstrated excellent corneal clarity with no complications.

Conclusions:

K2-EDTA is a safe and effective chelating agent for the surgical treatment of CBK. Compared to Na-EDTA it is lower in cost and can be obtained and prepared more easily. Early outcomes indicate that it may also have greater clinical efficacy. Further studies may enable the use of K2-EDTA to become widespread.

Financial Disclosure:

None