Chung-Ang University Hospital Ophthalmology Professor Kim Ji-taek's Team Identifies Cause of Intraocular Injection Inflammation

Difference in Aseptic Endophthalmitis Incidence by Syringe Type Confirmed
Immune Response Triggered by Silicone Oil Coating Inside Syringe Injected into Eye

Professor Kim Ji-taek, Department of Ophthalmology, Chung-Ang University Hospital.

[Asia Economy Reporter Lee Gwan-joo] A study has found that intraocular inflammation occasionally occurring after 'ocular injection' treatment, which involves administering medication into the eye to treat retinal diseases, may be caused by differences in the type and usage of syringes.

On the 21st, Professor Kim Ji-taek's ophthalmology team at Chung-Ang University Hospital analyzed the incidence rates of 'sterile endophthalmitis' occurring after intraocular injection treatment in a total of 498 patients who received injections using two different types of syringes. The results confirmed that the incidence of sterile endophthalmitis after injection varied significantly depending on the type of syringe used.

The syringes used in this study were two types: a '1㎖ disposable syringe' and a '1-㎖ Becton Dickinson Luer-Lok syringe.' The incidence rates of sterile endophthalmitis between the two groups were compared after intraocular injection. As a result, among 215 patients who used the 1㎖ disposable syringe, 6 patients (2.791%) were diagnosed with sterile endophthalmitis, whereas only 1 patient (0.353%) out of 283 patients who used the 1-㎖ Becton Dickinson Luer-Lok syringe was diagnosed with sterile endophthalmitis.

The research team attributed the lower risk of sterile endophthalmitis with the Luer-Lok syringe compared to the disposable syringe to silicone oil. Professor Kim Ji-taek explained, "When drawing the drug called 'aflibercept' into the syringe, small air bubbles typically form inside the syringe. To remove these air bubbles, the syringe is flicked, and depending on the syringe type, some of the silicone oil coating inside the syringe is administered into the eye along with the medication, forming a silicone oil/protein complex." He added, "Among the two types of syringes used in the study, the composition and amount of silicone oil in the general disposable syringe and the syringe's structure influenced the formation of the silicone oil/protein complex, which likely caused the difference in the incidence of endophthalmitis."

Professor Kim further stated, "To reduce the inflammatory response caused by silicone oil leading to sterile endophthalmitis, care should be taken to avoid creating air bubbles when drawing medication into the syringe during intraocular injection, and flicking the syringe should be minimized as much as possible." He also emphasized, "There is a need to introduce pre-filled aflibercept injection drugs in Korea."

Inflammation occurring after intraocular injection can be classified into 'infectious endophthalmitis,' related to bacterial infection, and 'sterile endophthalmitis,' which occurs without bacterial infection. Infectious endophthalmitis is caused by bacterial infection, but the cause of sterile endophthalmitis has been unclear. Although rare, severe cases can lead to vitreous opacity and vision loss, requiring oral and topical steroid treatments over several weeks. Previously, the immune response to the drug itself was generally considered the cause, but no clear causal relationship had been established.

This research paper was published in the latest issue of the International Ophthalmology Journal, a top 50% international journal in the field of ophthalmology.

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