None listed
Conditions
Brief summary
This double-masked randomised trial hopes to contribute to the overall effort in reducing the prevalence of myopia in general population or, at least, retard the progression of myopia in some children. It is designed with the following specific aims: 1) To assess the efficacy of the MC PAL 3 spectacle lenses for controlling the progression of myopia in children between the ages of 7 and 12 yrs relative to a SV control lens condition. 2) To assess the efficacy of two designs with 1.00 D addition and different peripheral near power profiles – a narrow near zone design and wide near zone design. 3) To assess the tolerance of children to wearing MC PAL 3 on a full time basis.
Interventions
Custom designed Progressive Addition Lenses worn binocularly during normal waking hours and for all tasks where spectacles can and normally would be worn. There are two designs, each having 1.00 D addition in the lower viewing zone and different peripheral near power profiles: one with rapid lateral rise in peripheral plus power (narrow near zone design) followed by an early drop off, and the other with a slow rise of peripheral plus power with late drop off (wide near zone design). Subjects are
Custom designed Progressive Addition Lenses worn binocularly during normal waking hours and for all tasks where spectacles can and normally would be worn. There are two designs, each having 1.00 D addition in the lower viewing zone and different peripheral near power profiles: one with rapid lateral rise in peripheral plus power (narrow near zone design) followed by an early drop off, and the other with a slow rise of peripheral plus power with late drop off (wide near zone design). Subjects are assigned to either of these designs or a single-vision lens control condition according to a pre-defined randomized sequence assigned on an incremental recruitment number. The study will compare the effectiveness of peripheral vision correction during near tasks with two different peripheral power profiles. The addition power will help reduce the accommodative demand of the wearer while doing near vision tasks (< 75 cm). The lens has a progressively increasing addition power starting at the distance viewing reference point and reaching the prescribed addition at approximately 12 mm below the fitting cross. The patient's regular prescription is additionally surfaced on the back surface of these lenses to correct any ocular errors of the eye. This may include sphere and / or cylinder corrections. Patients wear the lenses during normal waking hours and for all tasks where spectacles can be worn for a period of 24 months.
Sponsors
Carl Zeiss Vision
Study design
Allocation
Randomised controlled trial
Intervention model
Parallel
Primary purpose
Treatment
Masking
Blinded (masking used)
Eligibility
Sex/Gender
All
Age
7 Years to 12 Years
Healthy volunteers
Yes
Inclusion criteria
1) Spherical equivalent refractive error (SER) of –1.00 to -4.50 D 2) Astigmatism of not more than -1.50 D. 3) Anisometropia of not more than -1.50 D in spherical or cylindrical error. 4) Have best corrected visual acuity of at least 6/9 (20/30) in each eye. 5) Normal ocular health other than myopia. 6) No prior use of bifocal or progressive lenses in the last 12 months. 7) No RPG contact lens experience and must be willing not to wear contact lenses. 8) In satisfactory health. 9) Willing and able to tolerate cycloplegia (no previous adverse reaction to cycloplegics). 10) Informed parental consent.
Exclusion criteria
1) Any systemic condition which might affect refractive development or systemic diseases which may affect vision or refractive error. 2) Previous use of contact lens/PALs or other treatment for myopia within the last 12 months. 3) Defective binocular function. 4) Amblyopia and or manifested squint. 5) Vestibular disorders or motor imbalance. 6) Any other conditions precluding adherence to the Protocol. 7) Have best corrected visual acuity worse than 6/9 (20/30) in each eye.
Outcome results
None listed