The Association of British Dispensing Opticians will reveal results of a new clinical trial at Optrafair in Birmingham on Saturday 14th April.
When assessing a patient with low cylinder corrections, should you select a best sphere or a toric lens initially? The ABDO Contact Lens Uncorrected Cylinder Trial offers an insight into the positive and negative outcomes of the selection process and therefore enable the practitioner to make a more rational decision. It also points to areas where progress can be made to enable a Daily Disposable Toric Soft Contact Lens to become the lens of first choice.
Results of the trial indicate that toric daily disposable soft contact lenses (SCLs) SCLs give better objective and subjective vision for distance. However for intermediate and near vision the overall conclusions were less clear cut. It is interesting to hypothesise that the toric cyl axis may, in some cases, be influenced by the eyes convergence and inferior gaze and hence vision adversely affected.
Objective distance and near VAs improved at follow-up at two to three hours compared with dispensing at 20 minutes for the toric SCLs, whereas for the spherical SCL it hardly changed at all. In the same time period, the rotation ‘away from intended’ reduced dramatically in some subjects. This indicates that toric SCL assessments would be more accurately assessed at a longer time period than has been historically the case. If initial assessments are carried out at 20 minutes then it should be expected that more patients will be found not suitable than if assessed later.
Although toric lenses scored better (DVA) or at least equal (IVA & NVA) than spherical prescriptions, when it came to comfort, this result was reversed. Manufacturers should pay attention to improving comfort of toric lens design.
To find out more about the trial visit the Association of British Dispensing Opticians stand at Optrafair.