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

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

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

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

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.

Nernst – 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.

Calibration

Stepper Motor – Servo SystemPushing in and pushing out fluid

SensorEngineered by David

Engineered by David

Stepper Motor – Servo SystemPusing in and pushing out fluid