Vision Stability and Preference for Soft Toric vs. Soft Spherical Contact Lenses

Vision Stability and Preference for Soft Toric vs. Soft Spherical Contact Lenses

The principal hypothesis is to be tested in this work is that vision stability (the primary outcome measure) with a spherical contact lens correction vs. a toric contact lens correction will be the same.

This will be a randomised, subject-masked, crossover, bilateral non-dispensing study, controlled by cross-comparison. Thirty subjects will use each lens type at a single visit in random sequence.

Inclusion Criteria:

1. They are aged 18-35 years and have capacity to volunteer.

2. They understand their rights as a research subject and are willing and able to sign a Statement of Informed Consent.

3. They are willing and able to follow the protocol.

4. They are an existing wearer of soft spherical contact lenses in both eyes.

5. They have a spherical component of their spectacle refractive error between

   -0.50DS and -6.50DS in both eyes.

6. They have a cylindrical component of their spectacle refractive error between

   -0.75DC and -1.25DC in both eyes.

7. They can be fitted satisfactorily with both lens types.

8. They own an acceptable pair of spectacles.

9. They agree not to participate in other clinical research for the duration of the study.

Exclusion Criteria:

1. They have an ocular disorder which would normally contra-indicate contact lens wear.
2. They have a systemic disorder which would normally contra-indicate contact lens wear.
3. They are using any topical medication such as eye drops (including comfort drops) or ointment on a regular basis.
4. They are aphakic.
5. They have had corneal refractive surgery.
6. They have any corneal distortion resulting from previous hard or rigid lens wear or have keratoconus.
7. They are pregnant or breastfeeding.
8. They have any ocular abnormality which would, in the opinion of the investigator, normally contraindicate contact lens wear.
9. They have any infectious disease which would, in the opinion of the investigator, contraindicate contact lens wear or pose a risk to study personnel; or they have any immunosuppressive disease (e.g. HIV), or a history of anaphylaxis or severe allergic reaction.
10. They have taken part in any other contact lens or care solution clinical trial or research, within two weeks prior to starting this study.