Ocular surface changes following botulinum toxin injection for strabismus.

Area of Science:

• Ophthalmology
• Neurology

Background:

• Botulinum toxin injections are a common treatment for various conditions, including neuromuscular diseases, movement disorders, and strabismus.
• The impact of these injections on ocular surface health in strabismus patients requires further investigation.

Purpose of the Study:

• To evaluate the effects of botulinum toxin A injections on key ocular surface parameters in patients diagnosed with strabismus.
• To quantify changes in tear film stability, corneal staining, and subjective ocular surface disease over time post-injection.

Main Methods:

• A prospective study involving 26 patients undergoing botulinum toxin A for ocular misalignment.
• Ocular surface parameters, including tear break-up time (BUT), lissamine green (LG) staining, and Schirmer test, were assessed pre-injection and at multiple follow-up points (1 week to 6 months).
• Ocular Surface Disease Index (OSDI) questionnaire scores were also collected, with statistical analysis using ANOVA and non-parametric tests.

Main Results:

• Botulinum toxin A injections led to significant changes in tear break-up time (p=0.001), lissamine green staining (p=0.007), and OSDI scores (p=0.009) in the treated eyes.
• No significant changes were observed in Schirmer test results (p=0.266).
• The mean deviation at near and distance decreased post-injection.

Conclusions:

• Botulinum toxin injections appear to influence ocular surface parameters in patients with strabismus.
• While these observed effects on the ocular surface are likely temporary, they highlight a potential interaction between the toxin and ocular surface health.