Jai Mata Di The Mechanism for Defocus-driven Occular

Growth

The Eye

www.ahaf.org

Power (Diopters) focal length (metres)

1 D 1 m2 D .5 m

Convex lens (has a positive power e.g +1.5 D) focal point forms convergent light

Concave lens (has negative power e.g -2D) focal point is traced back from diverging light

Lens

http://www.math.ubc.ca/~cass/courses/m309-01a/chu/MirrorsLenses/lenses.htm

Lens Accommodation

http://www.sapdesignguild.org/editions/highlight_articles_01/images/accomodation.png

Emmetropia (normal vision)

Myopia (short sightedness)Corrected with negative power lens

Hyperopia ( Longsightness) Corrected with positive power glasses

Presbyopia (age-related changes)Range of accommodation depletion

Multifocal or bifocal lens correction

Disorders of optics of eye

Visual Abnormalities

http://www.merckmanuals.com/professional/sec09/ch099/ch099a.html

Retina/RPE/Choroid

http://www.maculacenter.com/LightBox/glossaryImages/rpe.jpg

Crucial for the maintenance of photoreceptor excitability

The main functions of the RPE are the following: (1) Transport of nutrients, ions, and water (2) absorption of light and protection against

photooxidation, (3) reisomerization of all-trans-retinal into 11-cis-retinal,

which is a key element of the visual cycle, (4) phagocytosis of shed photoreceptor membranes, and (5) secretion of various essential factors for the

structural integrity of the retina.

Retinal Pigment Epithelium

SUPER PROJECTNernst – Artificial Membrane

Diffusion of Ions Is there a transport of water?

Stepper Motor – Servo System Pusing in and pushing out fluid

Voltage Clamp Using fixed voltage and determining how much to change to

determine a transmission response

Fluid Flow Voltage Clamp Chamber

Artificial Membrane

Usual method is to have a 2 mm diameter hole in teflon sheet between aqueous solutions. Place 1 drop of (say) phospholipid in dodecane on hole and allow it to thin (as one would a soap bubble). Eventually get an optically black lipid bilayer film.

Artificial Membranes: How they are made?

Why use Artificial Membranes?Calibration

‘Nernst’

‘Puddle’Stepper Motor – Servo SystemPushing in and pushing out fluid

SensorEngineered by David

‘Stepper’

Engineered by David

Stepper Motor – Servo SystemPusing in and pushing out fluid

‘Puddle 2’ - also using an artificial membrane

RC-50 Imaging Ussing Chamber