Sublingual immunotherapy for allergic conjunctivitis: Cochrane systematic review and meta-analysis

Allergic conjunctivitis (AC) is a common manifestation and represents an important co-morbidity of allergic rhinitis (AR). Sublingual immunotherapy (SLIT) is an effective and safe treatment for nasal symptoms of AR; its effectiveness is however less well established for ocular symptoms.

To evaluate the effectiveness of SLIT in reducing ocular symptoms, the need for ocular treatments and the threshold exposure for conjunctival immediate allergen sensitivity (CIAS).

We searched eight databases up to January 2010. We included only randomized controlled trials (RCT), double-blind and placebo-controlled evaluating the efficacy of SLIT in patients with symptoms of allergic rhinoconjunctivitis (ARC) or AC. Primary outcome measures were total ocular symptom scores, individual ocular symptoms scores (itchy eyes, eye redness, watery eyes, swelling eyes), eye drops use and CIAS. Meta-analysis was undertaken using RevMan 5 software.

From 811 abstracts that were screened, 109 studies were reviewed in their full text version. Forty two trials including 3958 participants (n=2011 SLIT and n=1947 placebo) had data suitable for inclusion in the meta-analysis. SLIT induced a significant reduction on both total ocular symptom scores (SMD: -0.41; 95%CI: -0.53 to -0.28; I(2) : 59%) and individual ocular symptoms scores [red (-0.33; -0.45 to -0.22), itchy (-0.31; -0.42 to -0.20) and watery eyes (-0.23; -0.34 to -0.11)] compared with placebo. Participants in the SLIT group showed an increase in the threshold dose for the CIAS (SMD: 0.35; 0.00-0.69). No significant reduction was observed on eye drops use (SMD: -0.10; -0.22 to 0.03).

SLIT is effective in reducing total and individual ocular symptom scores in subjects with ARC or conjunctivitis. No significant reduction was observed in ocular eye drops use.