Rotational Stability of Toric Soft Contact Lenses During Natural Viewing Conditions

Abstract

The ACUVUE design was superior in stability for two of the four conditions tested. This resulted in a more stable lens immediately after insertion as well as during some visual tasks involving either naturally occurring or programmed large versional eye movements. Both lens designs provided acceptable performance in terms of induced astigmatism produced by off-axis rotation.

Comparison of fitting stability of the different soft toric contact lenses

“…After a settling time of 20 minutes, the subject positioned behind the slit lamp and gazed into primary position, the location of the toric lens marking(s) was identified for recording of lens orientation and rotational recovery. [11] Lens orientation was evaluated by narrowing the width of the slit lamp beam to approximately 0.5 mm and focusing on the lens surface at the 6 o'clock position on the lens axis marking(s). The vertical beam was slowly rotated to align lens marking and measure the amount of lens rotation.…”

“…To improve accuracy in measurement the light beam was passed through the center of the pupil. [6,11] Rotational recovery was assessed after determining the position of the lens axis marking(s) for each of the study contact lenses in primary position. While slit lamp magnification was set at 10x magnification, the contact lens was manually rotated 45° inferotemporally from primary gaze orientation.…”

Clinical evaluation of fitting toric soft contact lenses to current non‐users

“…Each subject was randomly assigned (irrespective of his/her preferred lens replacement schedule) to be fitted with one of two toric lens types: a daily disposable toric soft lens (1 Day Acuvue Moist for Astigmatism, Johnson & Johnson Vision Care http://www.acuvueprofessional.com/product/moist-astigmatism) or a 2‐weekly replacement toric soft lens (Acuvue Oasys for Astigmatism, Johnson & Johnson Vision Care http://www.acuvueprofessional.com/product/oasys-astig). Both lenses incorporate dynamic stabilisation (Accelerated Stabilisation Design, ASD) which has been found to have advantages over traditional toric designs, particularly in relation to rotational stability . The lens parameters used in the study are summarised in Table .…”

The visual and functional impacts of astigmatism and its clinical management

“…The quality of the optical correction of astigmatism with soft toric lenses is sometimes slightly inferior to that with spectacles because of various factors. After insertion, soft toric lenses typically require at least a few blinks to align themselves at the correct orientation in the eye and then show a small degree of rotational instability with each blink that can manifest as fluctuations in visual quality . The majority of disposable soft toric contact lens types that are available in the marketplace are also limited in terms of cylinder power (e.g.…”

“…After insertion, soft toric lenses typically require at least a few blinks to align themselves at the correct orientation in the eye and then show a small degree of rotational instability with each blink that can manifest as fluctuations in visual quality. 222,223 The majority of disposable soft toric contact lens types that are available in the marketplace are also limited in terms of cylinder power (e.g. often covering 0.75-2.25 D cylinders) and axes (e.g.…”