Eyes with abnormal tear film function have been found to show larger optical aberrations than normal eyes which may be attributed to the unstable and irregular tear film, uneven ocular surface, and increased scatter due to the exposure of the rough surface of corneal epithelium after tear break-up.

These hypotheses have been supported by the findings that instillation of artificial tears (sodium hyaluronate preparation) in dry eye patients reduces both corneal and ocular aberrations, improving the optical quality of the retinal image.

However, the previous studies only evaluated the short-term effects of a single administration of an artificial tear but did not determine the duration of action or inflection point at which the ocular aberrations increase back to baseline. Also, there has clearly been no such clinical trial that has been a well randomized controlled study to date.

This report is the first randomized controlled trial that investigated the long-term effects of a single dose of sodium hyaluronate-based artificial tears on wavefront aberrations in patients with dry eye.

Parameters used to determine treatment outcomes included ocular aberrations and severity of dry eye symptoms.

Inclusion Criteria:

1. Male or female patients aged 18 years or over.
2. Documented history of bilateral dry eye for at least 3 months.
3. Schirmer's I test (without anesthesia) less than 10 mm wetting/5 minutes for each eye.
4. Tear film break-up time (TBUT) less than 10 seconds for each eye.
5. Good compliance with the study regimen and availability for the duration of the entire study period.

Exclusion Criteria:

1. Pregnant or lactating women.
2. Contact lens wear.
3. Non-mydriatic pupil size less than 5.0 mm.
4. Other ocular surface pathologies or coexisting ocular diseases.
5. Ocular surgery or trauma within the past 4 months.
6. Use of concomitant eye drops or eye ointments within the past 2 weeks.
7. Abnormality of the nasolacrimal drainage apparatus.
8. Permanent or temporary occlusion of lacrimal puncta in any eye.
9. Known hypersensitivity to hyaluronic acid or any component used in the study.
10. Taking the following systemic medications within the previous 2 months: tricyclic antidepressive agents, anti-histaminic agents, phenothiazines, cholinergic agents, antimuscarinic agents, NSAIDs, beta-blockers, immunomodulators, anti-acneic agents, diuretics, corticosteroids and tetracyclines.
11. Very severe dry eye causing inaccurate aberrometry measurements.