Revisiting the influence of accommodation and accommodation disorders on the process of development and progression of myopia (literature review)
Authors: Myagkov Alexander , Karamyshev Pavel 
Published: March 2020

Purpose. To analyze domestic and foreign scientific publications over the past 5 years, reflecting the issues of accommodation and accommodation disorders. To assess the presence or absence of changes in the classification of accommodation disorders. To evaluate the role of various accommodation disorders in the development and progression of myopia.
Relevance. Given the significant increase in the number of people with myopia in recent decades, interest in the study of accommodation and accommodation disorders has increased again. This is due not only to the fact that accommodative insufficiency (AI, weak accommodation), is considered one of the leading factors in the development of myopia, but also because the use of one or another method of myopia control affects the process of accommodation, increasing or reducing accommodation reserves, affecting the functioning of the binocular system.
New developments in the field of visualization of intraocular structures (anterior segment imaging by OCT, Sheimpflug imaging, UBM) allows carry out previously impossible studies of changes in the crystalline lens, ciliary body, at different levels of accommodation response, in different age groups in vivo, which itself affects the development and testing of new concepts related to the mechanism of the accommodation.
Thus, the dynamics of the changes that are taking place motivates ophthalmologists to take a fresh look at the already established concepts of the accommodation mechanism, to assess the consistency of previously adopted approaches to the classification of accommodation disorders, which in turn can affect changes in the tactics of myopia control, which is especially crucial as myopization of the population, especially in children, is accelerating every day.
Our task was to evaluate domestic and foreign scientific publications over the past 5 years, reflecting the results of studies of the accommodation mechanism, assessing the influence of accommodation disorders on the progression of myopia. The task was also to assess the prospect of creating a unified classification of accommodative disturbances, the ability to create a unified algorithm for controlling progression, based on accommodation parameters.
Search strategy. A review of English and Russian sources related to the study of the mechanism of accommodation was conducted; the effect of accommodation disorders on the progression of myopia and their classification was studied using the following databases: PubMed, Cyberleninka, Google scholar, Elibrary. The search depth was 5 years (2014-2019), excluding the historical sources. The sources included:
- original research;
- historical issue, scanned publications;
- studies / descriptions of accommodation disorders and their relationship with myopia;
- abstracts and full-text publications;
- literary reviews;
- monographies.
The exclusion criteria were:
- themed issues with closed or restricted access.
During the process of searching and processing information, the data obtained were not systematized according to the level of reliability due to the fact that the purpose of the review is to obtain a general idea of the views on this issue, assess the presence or absence of unity in the formation of diagnostic criteria, without the task of suggesting practical recommendations.
The following search queries were made to search the databases:
a) English-language sources - mechanism of accommodation, accommodation AND history issue, accommodation AND Helmholtz AND Tsherning, accommodation AND myopia, accommodation AND myopia control AND myopia progression, accommodation disorders OR accommodation anomalies, accommodative excess AND accommodative infacility AND accommodative insufficiency, epidemiology myopia AND etiology myopia, near work AND myopia AND children;
b) Russian-language sources - the history of the study of accommodation, the mechanism of accommodation, classification of accommodation disorders, accommodation, accommodation disorders with myopia, accommodation and the progression of myopia, weakness of accommodation, habitual excess tension of accommodation; progressive myopia, myopia control.