December 21, 2024 /
Myopia, also known as short-sightedness or near vision impairment, is a common vision problem that typically begins in childhood and occurs when the eyes can focus clearly on nearby objects but are unable to focus on distant objects. This condition is usually caused by elongated eyeball or excessive corneal curvature, which causes incoming light to focus in front of the retina. The main causes of myopia include genetics, environmental factors such as prolonged near-point work and insufficient outdoor activity, and poor eye habits.
(DOI: 10.1038/s41572-020-00231-4)
Myopia is a global public health threat, especially in urban areas of East and Southeast Asia. In addition to the direct economic and social burden, related eye complications may cause significant visual impairment. Once myopia develops, the earlier it starts, the greater the likelihood of developing high myopia in the future. Prevention or delaying the onset of myopia may help improve long-term visual outcomes. Currently, optical correction is the main method for controlling the progression of childhood and adolescent myopia. Adult patients can use laser surgery, frame glasses/contact lenses, or ICL intraocular lens implantation. In terms of medication, initial studies have shown that M-receptor blockers (atropine) have a certain effect on controlling myopia progression, with less rebound, but the long-term efficacy and safety still need to be confirmed. Other drugs such as dopamine receptor agonists and 7-methylxanthine are still in the preclinical research stage and need further study.
PharmaLegacy has successfully established both acute and chronic myopia models, including one mouse model and three guinea pig models, with Atropine showing good efficacy in these models. The acute myopia model involves inducing ER stress in the eyes, which relaxes the collagen in the sclera and reduces the expression of type I collagen to induce changes in the eyes. With relatively short timeline and good consistency, this myopia model presents itself as a valuable tool for further research on the development of myopia and potential interventional treatments. PharmaLegacy has validated the model in both mice and guinea pigs, as well as the efficacy of atropine.
Figure 1: Acute myopia model
The chronic myopia model guinea pigs include the form-deprivation myopia (FDM) model and the lens-induced myopia (LIM) model. Form-deprivation myopia (FDM) is caused by blocking light from reaching the retina, severely damaging the animal’s form vision, and preventing the experiment animal’s retina from receiving a clear image, leading to myopia. Lens-induced myopia (LIM) is caused by wearing negative lenses to focus images behind the retina, leading to compensatory axial length growth and myopia. Guinea pigs have long been used for myopia research as they are docile, cooperative, and have large eyes that are easy for quantitative examinations.
In addition to the usual refractive and axial length examinations, we can also quantify choroidal thickness through OCT and visual acuity or contrast sensitivity through optomotor response (OMR) examinations. PharmaLegacy has validated the OMR in different rodents such as mice, rats, and guinea pigs.
Figure 2: FDM and LIM models
Please contact us for more model information and consultations.
Model list for Myopia
About PharmaLegacy’s Ophthalmology Platform
PharmaLegacy is an eye clinical pre-clinical platform supported by the “Shanghai Service Industry Development Guiding Funds”. It is equipped with a full range of small and large animal ophthalmic examination equipment, has established a three-level evaluation system from ocular tissue morphology and structure to visual electrophysiology and visual behavior, and is one of the most comprehensive platforms for intravitreal drug delivery in experimental animals. PharmaLegacy has successfully validated more than 60 ocular disease animal models, 10 exclusive models, and can provide services such as ophthalmic pharmacodynamics, ophthalmic DMPK, preliminary-toxicity, and ophthalmic device evaluation.