Dry Eye Treatment With Artificial Tears

Dry eye is a chronic irritating eye condition that affects many people, caused by poor tear quality and insufficient quantity. Treatments are traditionally in the form of artificial tears applied to the ocular surface. However, there is little evidence in the scientific literature that demonstrates their efficacy relative compared to each other, nor how to decide which one might be most effective for an individual patient. Therefore the investigators aim to examine the efficacy of different classes of artificial tears (those designed to increase viscosity, reduce evaporation or to mimic the component balance of the natural tears). In addition, the investigators also aim to determine how the treatment preferred by an individual could potentially have been predicted from their baseline condition.

The efficacy of different classes of artificial tears (non-pharmaceutical) will be examined in patients that report dry eyes by prescribing each category of treatment [0.40% Sodium Hyaluronate (Clinitas Soothe), 0.15% Sodium Hyaluronate (Hyabak), 0.25% Carboxymethylcellulose, electrolyte balanced (Theratears), and Phospholipid liposomal spray (Tears Again)] for a month in turn following a short wash-out period and to examine their tear film and ocular surface after each one.

Tear Supplement 3: Preservative free 0.25% Carboxymethylcellulose, electrolyte balanced (Theratears) applied as required for 1 month

Tear stability will be assessed using the Purkinje reflection from the tear film on the ocular surface recording the time (in seconds) that the reflection is first distorted, observed with a slit lamp biomicroscope

Tear meniscus height will be assessed in millimetres by comparing to the slit height adjustment of a slit lamp biomicroscope.

Lid parallel conjunctival folds will counted as observed with a slit lamp biomicroscope and timed/graded

Ocular surface staining with fluorescein and lissamine green dyes will be observed with a slitlamp biomicroscope and graded using the Efron grading scale

Tear volume will be quantified in millimetres after 15s with the tip inserted in the lower tear meniscus from the wetting height of a phenol red impregnated strip inserted in the lower fornix for 15 seconds

Inclusion Criteria: subjective symptoms indicative of dry eye Exclusion Criteria: Diabetes Sjögren's Syndrome recent ocular infection hay fever used any eye drops or ocular medications, were currently on medications known to affect the eyes wore contact lenses were pregnant.