Abstract
Abstract: :
Purpose: Castor oil emulsion eyedrops are lipid containing eyedrops which are thought to modify the tear film lipid layer and increase the tear film stability. The primary objectives of the investigation were to measure the residency time and quantify the effects of castor oil eyedrops on the tear film lipid layer of normal and dry eyes. A secondary objective was to quantify the initial effects on ocular symptomatology. Methods: The investigation was an open label unmasked pilot study carried out on 15 non contact lens wearers (5 normal and 10 reporting dry eye symptoms). A single non preserved emulsion eye drop (Investigational formula, Allergan) was instilled in each eye and the tear film appearance and composition were monitored for 4 hours post instillation. The tear film stability and the lipid layer thickness were evaluated with the TearscopeTM non invasive lighting system and slit lamp biomicroscope observation system at 15 minutes, 1 hour and 4 hours after eyedrop instillation. The tear lipid composition and the residual presence of castor oil in the tears were monitored via tear film sampling of the tear fluid and subsequent HPLC analysis at the same time periods. Results: The combined results for both normal and dry eye subjects show that: i. Castor oil presence was detected up to four hours post a single eyedrop instillation; ii. The volume of lipid present in the tear film increased post instillation; iii. The symptoms of dryness (p=0.006 to 0.024), itchiness (p=0.001 to 0.014), burning (p<0.001 to 0.039) and scratchiness (p=0.025 to 0.044) were significantly lower up to 4 hours post instillation; iv. A significantly lower incidence of thin tear film lipid patterns was recorded up to 1 hour post instillation compared to baseline particularly for the symptomatic subjects (p=0.031). Conclusions: This pilot investigation showed that castor oil emulsion eyedrops interact synergistically with the tear film lipid layer for up to 4 hours post instillation and produce an associated decrease in ocular symptoms. In general, a greater effect was observed for symptomatic patients.
Keywords: cornea: tears/tear film/dry eye • lipids