How is lens flexure diagnosed?

Diagnosing lens flexure typically involves conducting a sphero-cylindrical over-refraction. This method is effective because it helps to identify variations in vision that may occur when a soft contact lens is flexing on the eye due to factors like eyelid movement or changes in the eye's surface during blinking. When performing an over-refraction, an eye care professional can assess how the lens reacts and if it is altering the visual acuity. If lens flexure is present, this over-refraction may show unexpected cylinder power or axis that do not match the expected prescription.

Other methods, while valuable in assessing overall lens fit and ocular health, do not specifically identify lens flexure. Visual inspection focuses on the external appearance without providing insight into the optical performance affected by flexure. Fluorescein evaluation is primarily used to assess tear film distribution and surface interactions between the lens and the cornea, but it does not effectively reveal flexure's impact on vision. Corneal topography gives a detailed map of the cornea's shape but does not directly indicate how a contact lens may be flexing on the eye. Thus, sphero-cylindrical over-refraction stands out as the most appropriate and direct method for diagnosing lens flexure.