Abstract
Abstract: :
Purpose: Previous studies have demonstrated that the topical administration of ocular sympathetic pharmacological agents can produce significant changes in accommodation, particularly at higher stimulus levels. Additionally, reduced sympathetic innervation to accommodation has been associated with refractive error development, asthenopia and changes in the AC/A ratio. However, to date, few investigations have examined the effect of systemic adrenergic agonist medications on the accommodative response. Methods: A review of the clinical records of asthmatic patients between 17 and 25 years of age who were examined in the primary care clinic at the SUNY College of Optometry over the past 12 months was undertaken. These records were subdivided on the basis of whether the patient’s asthma treatment regimen included a systemic beta–agonist medication. Recorded findings of ocular accommodation in the beta–agonist group were contrasted with an age and sex matched control group of asthmatic patients whose medications did not include a beta–agonist agent. The following six clinical parameters were compared across these two groups: refractive error, amplitude of accommodation, positive and negative relative accommodation, near heterophoria and accommodative response as assessed by the dynamic cross cylinder test. Results: A total of 768 records were reviewed, of which 68 (8.9%) were asthma patients. Of these sixty eight cases, 25 (37%) were currently receiving beta–agonist medication. A significantly lower mean amplitude of accommodation (6.18D) was observed in subjects receiving beta–agonist therapy, when compared with the findings of the control group (mean= 8.06D). There was no significant difference between the two groups for any of the other parameters examined. Conclusions: These findings demonstrate that systemic beta–agonist medications can produce significant changes in accommodation. Furthermore, these accommodative changes may be a precursor to variations in other ocular parameters such as near heterophoria or the rate of refractive error development.
Keywords: refractive error development • myopia • ciliary muscle