Related Experiment Video
Updated: Apr 23, 2026
05:46
Author Spotlight: Advancements in Refractive Surgical Correction for Presbyopia and Exploring Postoperative Visual Acuity
Published on: September 20, 2024
892
Myopia control with positively aspherized progressive addition lenses: a 2-year, multicenter, randomized, controlled
Satoshi Hasebe1, Jiang Jun2, Saulius R Varnas3
1Department of Ophthalmology, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama, Japan Department of Ophthalmology 2, Kawasaki Medical School, Okayama, Japan.
Investigative Ophthalmology & Visual Science
|October 2, 2014
Summary
Positively aspherized progressive addition lenses (PA-PALs) with +1.5 D addition showed a 20% reduction in myopia progression over 24 months in children. However, the added distance zone aspherization did not enhance therapeutic efficacy beyond conventional methods.
Area of Science:
- Ophthalmology
- Optometry
- Pediatric Eye Care
Background:
- Myopia progression in children is a growing concern.
- Novel spectacle lens designs aim to slow myopia development.
- Positively aspherized progressive addition lenses (PA-PALs) are designed to reduce accommodative lag and peripheral hyperopic defocus.
Purpose of the Study:
- To evaluate the efficacy of PA-PALs in slowing the progression of early-onset myopia in children.
- To compare PA-PALs with different addition powers (+1.0 D and +1.5 D) against single vision lenses (SVLs).
Main Methods:
- A randomized controlled trial involving 197 children aged 6-12 years with myopia.
- Participants were assigned to wear SVLs, PA-PALs with +1.0 D addition, or PA-PALs with +1.5 D addition.
- Myopia progression was assessed via cycloplegic autorefraction every 6 months for 2 years.
Main Results:
- 169 children completed the 2-year follow-up.
- PA-PALs with +1.5 D addition demonstrated a statistically significant 20% retardation in myopia progression compared to SVLs (P=0.017).
- This effect was primarily observed in the first year, with negligible efficacy in the second year. PA-PALs with +1.0 D addition showed minimal efficacy.
Conclusions:
- The high positive aspherization in the distance zone of PA-PALs did not significantly enhance their therapeutic effect in slowing myopia progression.
- The efficacy of +1.5 D PA-PALs was comparable to conventional PALs for myopia control.
- Further research is needed to optimize spectacle lens designs for myopia management.
Related Concept Videos
01:16Focusing of Light in the Eye
6.0K
Light rays enter the eye through the cornea, a transparent dome-shaped tissue that is the eye's outermost layer. The cornea bends or refracts, light rays traveling to the pupil. The shape of the cornea determines how much of the light is bent and whether the image will be focused correctly on the retina at the back of the eye. Once the light has passed through both refraction layers, it converges into a single focal point onto a small area. This is where photoreceptors start transforming...
6.0K
01:28Angle Closure Glaucoma: Treatment
1.6K
Angle-closure glaucoma, or closed-angle glaucoma, is an eye condition where the iris bulges out and blocks the iridocorneal angle, resulting in a buildup of aqueous humor and increased intraocular pressure. Immediate medical attention is necessary due to the sudden onset of symptoms. The treatment for angle-closure glaucoma includes short-term and long-term approaches. Short-term treatment involves using eye drops like pilocarpine to lower intraocular pressure by increasing aqueous humor...
1.6K
01:27Open Angle Glaucoma: Treatment
1.0K
In open-angle glaucoma, the iridocorneal angle remains open, but the trabecular meshwork becomes stiff, slowing down the outflow of aqueous humor. This causes a buildup of aqueous humor in the anterior chamber, leading to a sudden increase in intraocular pressure. The treatment for open-angle glaucoma focuses on reducing the elevated intraocular pressure by either decreasing the secretion of aqueous humor or increasing its outflow.
Drugs such as carbonic anhydrase inhibitors, α2- and...
Drugs such as carbonic anhydrase inhibitors, α2- and...
1.0K
01:25Glaucoma: Overview
1.7K
Glaucoma is an eye condition characterized by increased intraocular pressure that damages the retina and optic nerve, leading to irreversible blindness if left untreated. The human eye has various components, including the cornea, iris, pupil, lens, and optic nerve. Aqueous humor is secreted by the epithelium of the ciliary body in the posterior chamber and flows through the trabecular meshwork and canal of Schlemm, maintaining normal intraocular pressure. The trabecular meshwork and the canal...
1.7K
01:23Ophthalmic Drug Delivery Systems
274
Ophthalmic drug delivery faces major limitations due to poor absorption across the corneal membrane. This process is primarily driven by diffusion and is influenced by two main factors: the physicochemical properties of the drug and tear drainage. Most ophthalmic drugs, such as pilocarpine, epinephrine, atropine, and local anesthetics, are weak bases. They are typically formulated at an acidic pH to enhance chemical stability. However, this leads to high ionization, reducing their ability to...
274
01:17Accessory Structures of the Eye
4.2K
Optical perception, or vision, is an extraordinary sense dependent on converting light signals received via the ocular organs. These organs, known as eyes, are securely positioned within the bony cavities of the skull, called orbits. The orbits serve a dual purpose: a protective shield for the ocular globes and a stable attachment point for the soft ocular tissues. The eye's external protective mechanisms include the eyelids, which are edged with lashes that act as a barrier against foreign...
4.2K