USING 3D VISION FOR THE DIAGNOSIS AND TREATMENT

OF AMBLYOPIA IN YOUNG CHILDREN

∗

Angelo Gargantini

Dip. di Ingegneria Informatica e Metodi Matenatici, Universit

a di Bergamo, Viale Marconi 5, Dalmine, Italy

Keywords:

Vision rehabilitation, Computer aided vision therapy, Amblyopia, 3D vision.

Abstract:

The 3D4Amb project aims at developing a system based on the NVIDIA 3D Vision for the diagnosis and

treatment of amblyopia in young children. It exploits the active shutter technology to provide binocular vision,

i.e. to show different images to the amblyotic (or lazy) and the normal eye. It would allow easy diagnosis of

amblyopia and its treatment by means of interactive games or other entertainment activities. It should not

suffer from the compliance problems of the classical treatment, it is suitable to domestic use, and it could at

least partially substitute occlusion or patching of the normal eye.

1 INTRODUCTION

Amblyopia, otherwise known as ‘lazy eye’, is reduced

visual acuity that results in poor or indistinct vision in

an eye that is otherwise physically normal, or out of

proportion to associated structural abnormalities. It

may exist even in the absence of any detectable or-

ganic disease. Typically amblyopia is present in only

one eye and is generally associated with a squint or

unequal lenses in the prescription spectacles. This

low vision is not correctable (or only partially) by

glasses or contact lenses.

There exist several causes of amblyopia. Anything

that interferes with clear vision in either eye during

the critical period (birth to 6 years of age) can re-

sult in amblyopia. The most common causes of am-

blyopia are constant strabismus (constant turn of one

eye), anisometropia (different vision/prescriptions in

each eye), and/or blockage of an eye due to trauma,

lid droop, etc. If one eye sees clearly and the other

sees a blur, the good eye and brain will inhibit the eye

with the blur. The brain, for some reason, does not

fully acknowledge the images seen by the amblyopic

or lazy eye. Thus, amblyopia is a neurologically ac-

tive process. The inhibition process (suppression) can

result in a permanent decrease of the vision in that

eye that can not be corrected with glasses, lenses, or

surgery. This condition affects 2-3% of the popula-

tion, which equates to conservatively around 10 mil-

This work is partially supported by NVIDIA corp. un-

der the Professor Partnerships program.

lion people under the age of 8 years worldwide.

Amblyopia is currently treated by wearing an ad-

hesive patch over the non-amblyopic eye for several

hours per day, over a period of several months. This

treatment can require up to 400 hours in total to be

effective (Cleary, 2000). This conventional patch-

ing or occlusion treatment for amblyopia often gives

disappointing results for several reasons: it is un-

popular, prolonged, and it can sometimes make the

squint worse because it disrupts whatever fusion there

is. These issues frequently results in poor or non-

compliance and since the success of patching depends

on compliance, it performs on average very poorly.

The treatment by itself works well, but it is often

abandoned because it is too much trouble to take.

Very often, children are averse to wearing a patch

and parents found occlusion difﬁcult to implement

(Dixon-Woods et al., 2006). For this reason, the or-

thoptists and ophthalmologists are continuously look-

ing for a more acceptable solution to the problem, i.e.

an effective treatment that is also complied with and

so really works (Gregson, 2002).

1.1 Computer based Treatment of

Amblyopia

In the last years, several research groups have ex-

perimented treatment of amblyopia by exploiting and

adapting information technologies. There exist sev-

eral Personal Computer (PC) based software pro-

grams that allow vision training but they still require

472

Gargantini A..

USING 3D VISION FOR THE DIAGNOSIS AND TREATMENT OF AMBLYOPIA IN YOUNG CHILDREN.

DOI: 10.5220/0003127204720476

In Proceedings of the International Conference on Health Informatics (HEALTHINF-2011), pages 472-476

ISBN: 978-989-8425-34-8

 2011 SCITEPRESS (Science and Technology Publications, Lda.)

Figure 1: The I-BiT

system. Copyright University of

Nottingham, printed with permission.

patching of the good eye. The most original system

which does not require patching, is described in the

following.

The VIRART group at the University of Notting-

ham has developed a novel virtual-reality (VR)-based

display system which avoids occlusion of the nonam-

blyopic eye and facilitates the treatment of amblyopia

with both eyes stimulated simultaneously (Eastgate

et al., 2005). This system is called I-BiT

TM2

. The

I-BiT

system itself consists of a viewer which is

linked to a PC. The PC has a standard monitor for

the clinician while the viewer allows binocular vision.

Several types of viewers were tested, like binocular

headsets and several types of viewers called ”cyber-

scopes” similar to that shown in Figure 1.

This system incorporates adapted VR technol-

ogy and specially written software providing interac-

tive 2D and 3D games and videos to the patient via

a stereo (binocular) display. Treatment consists of

watching video clips and playing interactive games in

the clinic with speciﬁcally designed software to allow

streamed binocular image presentation. The children

sit in front of the viewer and play with the software

designed for this kind of treatment.

An Evaluation of I-BiT

. The experiments show

that this type of treatment can be efﬁciently employed

and it performs better than the classical treatment. In

(Waddingham et al., 2006), the results of the use of

I-BiT

in six children are presented. In the case

study, treatment consisted of watching video clips and

playing simple interactive games with speciﬁcally de-

signed software to allow streamed binocular image

presentation via I-BiT

. Improvements in vision

were demonstrable within a short period of time, in

some children after 1h of treatment. However, the

proposed treatment has some limits. The kind of hard-

http://hfrg.nottingham.ac.uk/ibit/

ware system used makes the treatment rather costly

and performable only in suitable clinic rooms under

the supervision of a doctor (or at least of an adult).

The cure can be performed only for a limited time

and only with precise time scheduling. For these rea-

sons, we believe that the I-BiT

system suffers from

the same problem of compliance of the patching treat-

ment. The goal of this project is to design a system

which could combine the performance of I-BiT

but

be more accessible and usable.

Other research works present similar approaches

by using binocular head mounted display (HMD) or

similar tools to allow binocular vision. At the best

of our knowledge, no group has experimented the use

of the stereo 3D vision systems for the diagnose and

treatment of the amblyopia. In this paper we present

a project, 3D4AMB which is based on the 3D vision,

for the diagnosis and treatment of amblyopia in young

children.

2 USING THE 3D TECHNOLOGY

FOR BINOCULAR VISION

The main goal of this research project, called

3D4AMB, is to develop a system for the diagnosis

and treatment of amblyopia, based on the binocular

vision but that is accessible. With the term “accessi-

ble” we mean:

Inexpensive. The system needs to be relatively low

in cost, it must be affordable by a family. To be so

cheap, the system may be based on standard off

the shelf technologies, which could be bought in

stores open to the general public.

Friendly to Use. The system needs to be friendly in

its use such that the patients can use it without

requiring a particular education or skill. The sys-

tem may be operated autonomously by the chil-

dren themselves and the intervention of an adult

may be limited to initially set up the system (in-

stallation) and to start the treatment at least.

Suitable for Domestic Use. The system can be used

at home without frequent time-consuming visits

to the hospital. In this way, the timing of the treat-

ment can be decided by the patients. It may use

other domestic appliances like standard personal

computers and televisions.

Easily Extensible. It must be possible to easily de-

velop new applications and programs to be added

to the system. For this reason, standards and open

software libraries may be used for developing the

applications.

USING 3D VISION FOR THE DIAGNOSIS AND TREATMENT OF AMBLYOPIA IN YOUNG CHILDREN

473

We have devised a system which has all the above

characteristics and is based on the 3D technologies,

although the goal is not to provide the patients with

the 3D experience but to allow binocular vision. The

classical use of a 3D system is to provide the two eyes

with two different images of the same scene with a

slightly offset viewing angles which correspond to the

different viewpoints of our left and right eye. This vi-

sion produces an illusion of real depth of the scene

and it is the basis of the virtual reality. We exploit

only the capability of the 3D system to send two dif-

ferent images to the eyes while we do not want to

recreate a virtual reality.

Figure 2: Basic principle of the project.

We have already built a working prototype based

on the NVIDIA

 3D Vision

technology, although

other 3D technologies may be supported as well in

the future. The NVIDIA 3D vision is based on active

shutter technology which offers full image quality per

eye, wide viewing angle for 3D, excellent 2D Opera-

tion, and acceptable cost.

The system we have developed for 3D4AMB con-

sists in a normal PC desktop connected to a 3D mon-

itor (3D Vision-Ready Display). The PC must be 3D

capable and have all the 3D4AMB software installed

on it. The patient wears the NVIDIA active LCD

shutter glasses that allow viewing a different image

from the left and right eye. The scenario is depicted

in Figure 2.

The basic principle of the system is that the am-

blyopic or ‘lazy’ and the normal eye are shown two

different but related images. This principle can be

used in practice for the treatment of amblyopia, where

the amblyopic eye is shown the more interesting part

of the images of the clip or of the game, while the

non-amblyopic or ‘good’ eye is shown the less inter-

esting part of the image. The content to be shown by

the patient (game or image) is split by 3D4AMB in

two parts, one for the right eye (the amblyopic eye in

the Figure) and one for the left eye (the good eye in

the Figure). The 3D4AMB software will decide what

to send to both eyes depending on the type of treat-

ment suggested by the physician. Note that the lazy

eye of the child is more stimulated to work, but the

non-amblyopic eye is not patched. The patient brain

must join the two images to successfully see the com-

plete image and successfully perform simple tasks in

case of an interactive game. To make sure that the

patient can join the two images there are a signiﬁcant

number of elements common to both images. Note

that the ﬁnal image is a bidimensional image because

the goal in not to stimulate the stereo vision of the

patient (at least initially).

2.1 Use Cases of 3D4AMB

We have designed the following use cases that model

the ways we expect 3D4AMB will be used and the

possible interactions with physicians and patients. We

have also developed simple prototype applications to

prove that the designed usage of 3D4AMB is feasible.

Diagnosis. The 3D4AMB system can be used for

the screening and measurement of the amblyopia.

The physician will save the parameters correspond-

ing to the kind of amblyopia and these data will be

reloaded by the 3D4AMB software used by the pa-

tient. In Figure 3 we show a simple application that

permits to measure the squint between the two eyes.

Two circles are shown to the patient, one for each eye.

The two circles are translated until the patient sees

only one circle.

Figure 3: Diagnosis Application.

Passive Image and Movie Viewing. Another use of

3D4AMB is to visualize images and clips. 3D4AMB

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includes an image and video viewer that is able to

send two different images to both eyes. This activ-

ity, although it is passive, since it does not require any

action by the child, could be performed for prolonged

time and would allow to exercise the lazy eye while

performing activities, like watching movies, likely to

be appealing for children.

Video Games and Exercises. While patching is a

passive method, other treatments which require some

activity on the part of the patients are classiﬁed as ac-

tive. Active methods are intended to enhance treat-

ment of amblyopia in a number of ways, including

increased compliance and attention during the treat-

ment periods (due to activities that are interesting for

the patient) and the use of stimuli designed to activate

and to encourage connectivity between certain corti-

cal cell types.

The most advanced and active use of 3D4AMB is

the active playing with interactive games or exercises,

which will stream binocular images. It is well known

that video games can be very useful for visual reha-

bilitation (Achtman et al., 2008). In this settings, the

child plays with a special video game which sends to

the lazy eye all the details while the normal eye will

see only a part of the game scene. To successfully

complete the game the patient must use the informa-

tion shown to the lazy eye (and fuse it with that shown

to the normal eye). In this way, the amblyotic eye

is more stimulated and the fusion encouraged. The

game application can continuously monitor the suc-

cess rate of the game in order to adjust the difﬁculty

based on the real capability of the player.

We have developed a small space invaders games

shown in Figure 4 in which the entire scene is pre-

sented to the lazy eye, while the normal eye does

not see the spacecraft (red in the Figure) and the

shots (yellow in the Figure). The player must hit the

invaders (green in the Figure) ﬁring some shots by

pressing the space bar on the keyboard (or a ﬁre but-

ton of a joystick). Some parts of the background (in

yellow in the Figure) are shown to both eyes to facili-

tate fusion.

(a) Normal Eye. (b) Lazy Eye.

Figure 4: Space Invaders Game.

2.2 Software Architecture

The 3D4AMB software is based on several compo-

nents which facilitate the development of new ap-

plications. The system works only (up to now)

on a PC with Microsoft Windows

 Vista 32/64-bit

or Windows 7 32/64-bit Operative systems with the

NVIDIA 3D Vision drivers and with Sun Microsys-

tems Java Runtime Environment. It is based on the

Java OpenGL (JOGL) which is a wrapper library that

allows OpenGL to be used in the Java programming

language. It is currently an independent open-source

project under the BSD license and on Jadis (Java Ad-

vanced Display Infrastracture for Stereo) which pro-

vides a common interface for displaying Swing GUI

components in stereo.

3 CONCLUSIONS

In this paper we have presented a system, 3D4AMB,

for the diagnosis and treatment of amblyopia in young

children which is based on 3D vision technologies.

The 3D vision is exploited to allow the binocular vi-

sion, i.e. to send different images to the normal and

the lazy eye, in order to exercise and stimulate the lazy

eye and the brain to fuse the images in an unique view.

We have presented several use cases supported by

prototypes we have developed using Java and JOGL

technologies for stereo viewing. The system has been

devised with the goal to improve compliance with

the treatment. It should not suffer from the non-

compliance problems of the classical patching treat-

ment. The children should enjoy the domestic use of

3D4AMB games and exercises, allowing prolonged

therapy and the system promise to be inexpensive

enough to foster its usage.

REFERENCES

Achtman, R., Green, C., and Bavelier, D. (2008). Video

games as a tool to train visual skills. Restorative Neu-

rology and Neuroscience, 26(4-5):435–446.

Cleary, M. (2000). Efﬁcacy of occlusion for strabismic am-

blyopia: can an optimal duration be identiﬁed? British

Journal of Ophthalmology, 84(6):572–578.

Dixon-Woods, M., Awan, M., and Gottlob, I. (2006).

Why is compliance with occlusion therapy for ambly-

opia so hard? a qualitative study. Arch Dis Child,

91(6):491494.

Eastgate, R. M., Grifﬁths, G. D., Waddingham, P. E.,

Moody, A. D., Butler, T. K. H., Cobb, S. V., Comaish,

I. F., Haworth, S. M., Gregson, R. M., Ash, I. M., and

USING 3D VISION FOR THE DIAGNOSIS AND TREATMENT OF AMBLYOPIA IN YOUNG CHILDREN

475

Brown, S. M. (2005). Modiﬁed virtual reality technol-

ogy for treatment of amblyopia. Eye, 20(3):370–374.

Gregson, R. (2002). Why are we so bad at treating ambly-

opia? Eye, 16(4):461–462.

Waddingham, P. E., Butler, T. K. H., Cobb, S. V., Moody,

A. D. R., Comaish, I. F., Haworth, S. M., Gregson,

R. M., Ash, I. M., Brown, S. M., Eastgate, R. M.,

and Grifﬁths, G. D. (2006). Preliminary results from

the use of the novel interactive binocular treatment (I-

BiT[trade]) system, in the treatment of strabismic and

anisometropic amblyopia. Eye, 20(3):375–378.

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