Analysis of accommodation function with ultrasonography.

Abstract

The aim of this study was to present a new method that uses ultrasonography to analyse accommodation function, and to do a preliminary investigation of its possible use in clinical practice. Using the method of continuous ultrasonographic biometry, changes in lens thickness were measured during accommodation. From these measurements response latency and duration were determined. Normal values for latency and duration were obtained by measuring 20 healthy subjects of different ages. Measurements were also performed on three patients with different accommodation disorders: diabetes, Adie's syndrome and third nerve palsy. Normal response latency is 394 ms (+/-46 SD) and independent of are. Normal response duration increases with age from an average 306 ms at 15 years-of-age to an average 954 ms at 55 years-of-age. Normal latency as well as duration appear to have a large interindividual variability. The diabetic patient had a delayed latency but a normal response duration. The patient with Adie's syndrome had a delayed latency and prolonged duration. The patient with third nerve palsy had a normal latency and duration. We conclude that ultrasonographically determine latency and duration give additional information on accommodation function that is more complete and objective than maximum accommodative amplitude alone. The results in our patients suggest that, in selected cases, this information may aid in the diagnosis and management of patient's complaints.