This single-center, randomized, double-blind, crossover clinical trial aims to compare the volumetric visual fields provided by two occupational progressive addition lenses (OPLs) optimized for intermediate and near vision in presbyopic patients. The study evaluates Vimax PC 1.5 FWD 133 cm and Vimax PC 1.5 FWD 200 cm lenses and Vimax Fit FRM, all of them with plano distance power and a +2.00 D near addition, in order to determine differences in the extent of clear vision at multiple working distances.
Participants will undergo a comprehensive optometric examination including medical and ocular history, visual acuity assessment, accommodative amplitude measurement, autorefraction, interpupillary distance measurement, ocular motility evaluation, confrontation visual fields, Amsler grid testing, and binocular vision assessment. Visual field measurements will then be performed using both study lenses under standardized conditions. Subjects will be instructed to maintain a fixed head position while identifying optotypes located at distances of 4 m, 2 m, 1.33 m, 80 cm, 40 cm, and 25 cm. Both lenses will be tested in random order under masked conditions so that neither participants nor investigators know which lens design is being evaluated during each phase.
At least 23 presbyopic participants are expected to be enrolled. The study procedures are non-invasive and are anticipated to be completed in a single one-hour visit, although additional sessions may be scheduled if necessary. No significant risks are expected beyond possible transient visual fatigue associated with the duration of testing.
The primary objective is to determine which occupational progressive lens design provides a greater spatial volume of clear vision and wider horizontal and vertical visual fields at different intermediate and near distances. The findings may contribute to improving personalized recommendations of occupational lenses according to patients' visual demands and working distances.
• Spherical ametropia for distance vision ≤ ±4.00 D and astigmatic ametropia ≤ 1.00 D.
Decimal VA ≥ 0.8, either uncorrected (UCVA) or corrected (BCVA) with monofocal contact lenses.
Patients with a nasopupillary distance (NPD) of 31 mm, with a tolerance of ±2 mm in each eye
Astigmatism greater than ±1.00 D.
Patients wearing progressive contact lenses.
Patients who have undergone cataract surgery or have monofocal or multifocal intraocular lenses.
Anisometropia greater than 2.50 D.
Crossover
OPAL PC 133 assessment
DeviceFitting and positioning of the spectacles : participants were instructed to move only their eyes and to verbally identify the letters indicated by the optometrist. Measurement of clear vision limits: the horizontal and vertical boundaries of clear vision were recorded on a scaled results sheet, as defined by the participant using the optotype, at distances of 400, 200, 133, 80, 40, and 25 cm, in that order.
OPAL PC 200 assessment
DeviceFitting and positioning of the spectacles : participants were instructed to move only their eyes and to verbally identify the letters indicated by the optometrist. Measurement of clear vision limits: the horizontal and vertical boundaries of clear vision were recorded on a scaled results sheet, as defined by the participant using the optotype, at distances of 400, 200, 133, 80, 40, and 25 cm, in that order
PAL assessment
DeviceFitting and positioning of the spectacles : participants were instructed to move only their eyes and to verbally identify the letters indicated by the optometrist. Measurement of clear vision limits: the horizontal and vertical boundaries of clear vision were recorded on a scaled results sheet, as defined by the participant using the optotype, at distances of 400, 200, 133, 80, 40, and 25 cm, in that order
Visual field volume
It will consist of the volume defined by two parallel surfaces bounded by the visual fields perceived with clear horizontal and vertical vision by the patient between the distances of 4 m and 25 cm while wearing each pair of spectacles. The volume will be calculated using the Heronian formula for the volume of a quadrangular pyramidal frustum.
Visual fields surface
Calculation of the visual field surface areas defined by the patient with each lens type at distances of 4 m, 2 m, 1.33 m, 80 cm, 40 cm, and 25 cm. For this purpose, the areas corresponding to the visual field regions of the lens located between the fitting cross and the intermediate and near viewing zones were summed in a 1:2 proportion, respectively, for each measured distance.
Click on the lead sponsor to view all of their trials.
