Gradient Myopic Defocus Causes Chick Scleral Tissue Reinforcement and Structural Scleral Remodeling.

Area of Science:

• Ophthalmology
• Developmental Biology
• Histology

Background:

• Myopia progression is a significant concern in pediatric eye care.
• Scleral remodeling plays a crucial role in refractive error development and progression.
• Controlling myopia progression often involves interventions targeting ocular growth and structure.

Purpose of the Study:

• To investigate the histological effects of myopia progression control (MPC) lenses on scleral remodeling.
• To determine if MPC lens-induced refractive changes can alter scleral tissue in chicks.

Main Methods:

• 24 chicks were used, divided into groups wearing conventional -10D lenses, +10D lenses, or MPC lenses for 7 days after an initial 7-day period with -10D lenses.
• MPC lenses featured a central power of -10D with a gradient power rise at the pupil edge (+2.75D).
• Eyes were processed for histopathological evaluation, including H&E staining and bright field microscopy.

Main Results:

• Conventional -10D lenses significantly reduced total scleral thickness.
• MPC lenses did not reduce scleral thickness compared to controls.
• Appositional growth of the cartilaginous sclera (CS) was observed exclusively in MPC lens-treated eyes, showing increased CS thickness.

Conclusions:

• Appositional growth in chick scleral hyaline cartilage can be induced.
• MPC lenses, by reversing experimental myopia, successfully stimulated scleral cartilage growth.
• A gradient decrease in peripheral lens power may trigger scleral reinforcement via cartilage growth stimulation.