Purpose: As shown by the clinical picture of progressive myopia, derangements in biomechanical properties of sclera may be more or less manifested. The study aims at the development of a discriminating approach to their correction.
Methods: Patients with the condition were given a sclera strengthening injection, in which a dose of liquid polymeric composition is injected under the Tenon's capsule on the scleral surface. After polymerization, the composition forms over the scleral surface a layer of elastic foamed gel.
Results: Complex experiments on 146 rabbit eyes showed that the injected material promotes collagen formation. Gradually dissolving, the gel stimulates the growth of connective tissue on the surface of the sclera, whose stress-strain parameters improve. A thorough clinical study of 240 eyes of patients aged 8-25 years with progressive 6-10 D myopia showed that the refraction remained stable in 79.6% eyes 1 year after the sclera strengthening injection and in 52.9% cases 4-9 years after the sclera strengthening injection. At the same time, fellow intact eyes have shown, respectively, 40.3% and 13.3% of myopia stabilization, and 212 untreated eyes of the control group 26.0% and 11.1%, respectively. 612 children and adolescents with high myopia and a yearly progression of over 1.0 D were subjected to a scleroplastic operation. It was found that the myopia remained stable in 95.7% cases 1 year after the operation, and in 71.9%, 7 years after the operation. If myopia progression continued after a sclera strengthening injection or scleroplasty, a second procedure was performed. Second interventions were effected on 118 eyes of 102 patients, including 42 eyes where a sclera strengthening injection followed a sclera strengthening injection, 27 eyes where scleroplasty followed a sclera strengthening injection, 31 eyes where a sclera strengthening injection followed scleroplasty, and 18 eyes on which a second scleroplasty was performed. Second interventions provide a double decrease of myopia progression rate and, in 63% of patients, stop the progression altogether.
Conclusion: It can be concluded that nonsurgical and surgical techniques of correcting the biomechanical properties of sclera for the treatment of progressive myopia as well as discriminative methods of determining the indications to these procedures have proven to be effective.