**7. Conclusions**

Although the cause of myopia in humans is complex, clinical and experimental studies indicate that failure of the emmetropization process often leads to the development of myopia. It has been well-established that visually induced changes in ocular length are the result of altered extracellular matrix remodeling of the scleral shell. However no therapeutic targets have been identified and no pharmaceutical or optometric approaches have proven effective for the treatment of high myopia. The increasing prevalence of myopia and earlier age of onset emphasize the need for the development of an effective therapy. The identification of choroidal atRA, RALDH2, and the choroidal cells responsible for atRA synthesis, may provide new targets for the development of effective myopia therapies. Moreover the development of small molecule inhibitors specifically targeting RALDH2 would greatly expand our basic understanding atRA's role in postnatal growth and development as well as provide potential new therapies to slow or prevent the progression of myopia.
