OSD Treatment Gets Alternative Touch

Topical azithromycin for OSD may reduce systemic side effects. Dermot McGrath reports

Topical application of azithromycin may provide an acceptable alternative to systemic doxycycline in patients with meibomian gland dysfunction (MGD), a recent study suggests.

“Our study showed that systemic side effects were less common with azithromycin compared to systemic doxycycline without losing any efficacy in terms of improving the signs and symptoms of ocular surface disease (OSD) in patients with MGD,” reported Andreas Schlatter MD.

MGD is a major cause of ocular surface disease, with treatment strategies including but not limited to lid hygiene for mild cases and anti-inflammatory treatment for more severe cases. Although both topical azithromycin and systemic doxycycline have been found effective in MGD, the effect of both therapies on tear film thickness (TFT) remains unclear. The efficacy of topical azithromycin for the treatment of MGD has been attributed to its anti-inflammatory and antibacterial properties, which may suppress MGD-associated posterior blepharitis and bacterial growth on the eyelid.

In Dr Schlatter’s study, 23 patients with MGD were randomised to either receive 15 mg/g topical azithromycin twice daily in both eyes for two days, then once daily for 26 days, or 100 mg oral doxycycline twice daily for six weeks. In total, four study visits at intervals of two weeks were scheduled.

The main study outcome was a change in tear film thickness as measured with ultra-high resolution optical coherence tomography (UHR-OCT). Ocular Surface Disease Index (OSDI), OSD composite sign score, lipid layer thickness (LLT), tear film osmolarity, conjunctival staining (as assessed with Lissamine green), and Schirmer I test served as secondary outcomes.

TFT significantly increased in both groups with no statistical difference between them. Additionally, OSDI score and OSD composite signs significantly decreased in both groups. There were no significant changes in LLT, tear film osmolarity, conjunctival staining, or Schirmer I test. Systemic adverse events were more frequent in the doxycycline group, while mainly local adverse events occurred in the azithromycin group.

“The adverse events in the azithromycin group were mainly eye related, with burning eyes the main symptom identified. Two patients discontinued treatment as a result. Headache and gastrointestinal symptoms were the most frequent adverse events for patients treated with systemic doxycycline, with one patient discontinuing treatment as a result,” Dr Schlatter said.

Summing up, Dr Schlatter said the study showed both treatment regimens improved TFT in addition to signs and symptoms of OSD.

“The increase observed in tear film thickness can probably be attributed to an increase in the thickness of the aqueous layer. There were [fewer] systemic adverse events in the azithromycin group, and the treatment can therefore be considered a viable alternative to systemic doxycycline,” he said.

Dr Schlatter added that larger sample sizes and a longer observation time would be needed in future studies to confirm these initial findings.

“Our study showed that systemic side effects were less common with azithromycin compared to systemic doxycycline without losing any efficacy in terms of improving the signs and symptoms of ocular surface disease (OSD) in patients with MGD.”

He presented the results of the study at the ESCRS Virtual Winter Meeting 2022.

Andreas Schlatter MD is a research associate at the Medical University of Vienna, Austria, and the Vienna Institute for Research in Ocular Surgery (VIROS), Austria. andreas.schlatter@meduniwien.ac.at