Imaging And Biometry Of The Human Eye During Accommodation Using Spectral Domain Oct

Abstract

 

Purpose:

 

To image and quantify the dynamics of the human eye during accommodation in real-time using spectral domain OCT with extended depth.

 

Methods:

 

A spectral domain OCT system was developed to measure intraocular distances and surface shapes along the entire depth of the eye, and their changes during accommodation. The spectrometer of the OCT system produces single frame imaging with an axial resolution of 8μm and an axial range of about 10mm (in air) at a speed of 40,000 A-lines/s. The eye was imaged with 3 frames recorded at different depths that cover the anterior segment and the retina. The delivery probe of the OCT system was coupled with a custom made unit that provides monocular accommodation/disaccommodation stimuli stepping from distance to between 0D and 10D near target vergence to allow imaging and measurement of the real-time dynamic accommodative response of the eye.The responses to accommodative and disaccommodative step stimuli were measured in the right eye a 35 year-old subject.

 

Results:

 

Images acquired on a 35-year old subject are shown below. The images show the changes occurring in the eye when a 0D and 7D stimuli are induced to the subject's eye. The ocular distances were measured during accommodation and disaccommodation. In the relaxed state (0D), the thickness of the crystalline lens was 3.90mm and increased of 0.19mm when the accommodation stimulus (7D) was provided. The anterior chamber depth was 3.51mm in the relaxed states (0D) and decreased of 0.12mm after the accommodation stimulus (7D) was provided. The axial length of the eye measured from the anterior corneal surface to the anterior retinal surface was 24.88mm in the relaxed state and 24.67mm in the accommodative state (7D).

 

Conclusions:

 

The study demonstrates the feasibility of performing imaging and biometry of the eye dynamics along its entire length during accommodation and disaccommodation and in real-time using OCT. Support: NEI Grant 2R01EY14225, 2R43EY018021, P30EY14801 (Center Grant); Australian Government CRC Scheme (Vision CRC), Bioptigen (NC); Florida Lions Eye Bank; Research to Prevent Blindness; The Henri and Flore Lesieur Foundation (JMP).  

 

Keywords: imaging methods (CT, FA, ICG, MRI, OCT, RTA, SLO, ultrasound) • accommodation • anterior segment