Leung Lab Blog

Since our lab is studying retina, I am intrigued in reading this article about the limitation of retina display by Apple, how we see and the future of developing better displays.

From cultofmac by John Brownlee: Why Retina Isn’t Enough

Apple’s new MacBook Pro follows the fine tradition of the iPhone 4 and third-gen iPad in that it has a super high-resolution Retina display: a 2880 x 1800 panel with an amazing 220 pixels packed in per inch.

It’s an incredible display. In fact, it’s such an incredible display that it actually has about one million, seven hundred thousand pixels more than it needs to satisfy Apple’s definition of Retina, leading some to claim that those pixels are all going to waste.

Nothing could be further from the truth.

Apple’s new MacBook Pros have absolutely great displays, but they need every single pixel they have, because the truth of the matter is that Apple’s got a long way to go before it catches its display tech up to the incredible power of human vision. And that’s a good thing, because it means we’ve got a lot to look forward to.

From http://www.cultofmac.com

Retinal Development

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Stem cells

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Genetics

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Genomics

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Systems Biology

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Neuroscience

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Vision

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Education

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Medical Research

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Zebrafish

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Evolution

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We have recently begun to work on a project that requires us to find out whether a zebrafish larva can see or not. To this end, we have built a small machine to check whether the larvae show optokinetic response (OKR), a visual behaviour.

This video shows the OKR machine, which is essentially a drum with black and white stripes that the rotating direction is controlled by a motor.

The fish larvae will be immobilized by thick solution in a Petri dish, which will be put inside the drum. The larvae with normal vision will be able to track the rotation and move their eye balls. In this video, the bottom larva shows a normal OKR response, while the top one, a blind larva caused by a genetic mutation, does not show the OKR response. An an bubble is put on the left to reflect the direction of the stripe movement.

During the process of fabricating this machine, we had come across with another cheaper way to do the same thing. There is a type of ancient Chinese lantern that part of outside drum will move due to heat convection generated by the light (A picture can be found in this Chinese article). We bought a contemporary version that the moving drums are driven by motor. The type that we bought has the moving mechanism for rotating in opposite direction. We then took apart the lantern and used the moving mechanism to drive the opposite rotating stripes. See the following video for the moving mechanism of this alternative version of OKR.

Even though it is not perfect, it works! The most amazing part is the difference in the cost of fabrication.

• OKR made from Chinese Lantern: ~ $US 3 (for buying the Chinese Lantern)
• OKR that is properly made as shown in the first video: ~$US 150 (for materials) + ~$600 (for labor) = ~ $800 (and that does not include the controller box) !!!

That is actually another example of the difference in the cost structure in doing research between the East and the West!

I also had a lot of fun sourcing other cheap parts for the final setup. For example, I have bought a very decent eye-piece camera for less than $40 (the price seems to have gone up a bit since then… but is still very cheap) to capture the video of larval eye movement as shown in the second video. I have also bought a very economical ring light from AmScope for less than $60 for illuminating the drum area finally.

We are going to use this assay to identify fish with eye problems and then characterize the underlying molecular defects. That will help us study and find cures for the same diseases in human.

I read several classic papers when I am planning projects with some of you. This is a very good review paper on the fundamental architecture of retina. There are a lot useful histological facts and observations. It has great discussions on how the retinal architecture has evolved and in turn provides the necessary visual functions to the animal. I believe you will also find this review paper useful.

Reference

Masland RH. The fundamental plan of the retina. Nat Neurosci. 2001 Sep;4(9):877-86.[PubMed][Nat Neurosci]