Bangalore/New York City

Prototype to measure cataract

A diagnostic tool to measure cataract build at MIT DIY 2013.

A mobile diagnostic tool to measure cataract

A hardware prototype designed at MIT DIY workshop 2013

cataract-diagnostic-tool.png
 
 

India's vision related issues would double by 2020

Vision related issues are the most pertinent issue among the elderly. It has been projected that the number of elderly citizen undergoing surgery would double by 2020. Our project attempts to quantify the density of cataract so that appropriate test/medical advice can be supervised on time. This is especially relevant in rural areas where medical facilities are limited and multiple cataract tests may not be affordable. This is an early cataract detection hardware application that detects, quantifies and helps the medical professional give more accurate advice and follow-up with the patients.

The Cause behind Cataract

Stereo illusion, also known as Pulfrich effect, is a psycho-physical perception in cataract patients. Objects moving laterally apparently seem to gain depth. The visual cortex interprets the lateral motion as having a depth component, due to a relative difference in receiving signals by both the eyes. Pulfrich effect makes the cataract patients especially subject to accidents.

Tom Scott explaining Pulfrich effect.

List of features to build a working prototype

  • Analyzing methods to understand how to work with low-vision people.

  • Stimulating the physical perception into digital format.

  • Finding the correct parameters.

  • Simulation of virtual reality pendulum

  • Creating virtual filters

  • Measurement

 

Testing the prototype

Saurabh Bhide tests the prototype. The white shell is attached with a smartphone that displays a test image. It’s further connected to a camera to detect the eye motion to understand the deviation of the pupil from the median.

Technological challenge

The biggest technological challenge lied in quantifying the precise depth of cataract through pupil tracking. In other words, translating the physical lateral motion to digital motion was a roadblock. The following list describes the steps we followed:
- Translating the analogue system into the digital format.
- Quantifying the depth (eye tracking mechanism): We worked with different variables. The trials were conducted based on the following parameters:

  • Background

  • Size of pendulum

  • Screen speed

  • Colour variation

  • Shape of the pendulum, and

  • Tracking the eye was not feasible at this stage as it requires really high pixel cameras and more duration for the trials.


Future work

Though the application was never launched. We made the code open-source to benefit the medical community. This prototype also leaves gaps for future work including:

  • Quantify the depth of perception based on the current experiment to get a relative value of cataract.

  • Track the eye movement to get more precise data.

  • Design the application such that it is easy to use in rural areas.


Software tools 

Android IDE and Processing (code hosted here)

Team

Research and prototyperAniruddha Daheria (designer), Kishore Kumar Jagini (optometric researcher), Paulami Roychoudhury (experience designer), Saurabh Bhide (engineer) | Mentored by : Amy Canham (MS Candidate, MIT Media Lab), Everett Lawson( PhD Candidate, MIT Media Lab) | Clinical mentor: Shrikant R. Bharadwaj( Scientist, Head of Optometry, LV Prasad Eye Institute)

Date : JuLY 2013