Dorothea Kohlhaas – Second Sight Patient Case Study


Dorothea, 48, works as a legal secretary at the Court in Daun, in the Vulkaneifel area of Western Germany, and is married to Peter Philip who also has a visual impairment. They have two guide dogs: Dorothea’s is a Labrador called Trixi; Peter’s is a Collie called Anubia.

Dorothea, who is totally blind due to the genetic eye condition Retinitis Pigmentosa, received an Argus II retinal implant at the Cologne University Hospital on 8th October 2013.

She says:

“I was visually impaired since birth, but when I was 29, doctors diagnosed my RP. I grew up with poor vision, but I was able to read and see most things, and I went to a normal school. I wore very high prescription glasses and sat in the front row of the classroom so I could see the teacher.

I decided to have the Argus II treatment because, for me, I felt I had nothing to lose: I didn’t have high expectations, I was curious. At that time, I had no vision left at all – I could not see anything. I was totally blind. It wasn’t black – everything was grey like a thick fog.


I wanted to do something for research – if nobody wants to take a risk to try a new treatment, medical science can’t advance and progress.

The biggest benefit I receive from the system is that I have much better orientation outside or inside a place I don’t know. When I am outside I can perceive the edge of the kerb or a pedestrian crossing. It means I can go out by myself. I have more autonomy. I feel safer, and happier going outside on my own. I have a better quality of life – it’s a great thing to do just to behave like anyone else. I don’t have to wait for Peter or friends to take me out.”


“Walking is a passion of mine. I live in the countryside: in a village with about 700 people. There are no big cities – Cologne is the nearest city and it’s 100km away. In this area, there are just small towns and a lot of countryside – lovely forests and lots of 500-600 metre mountains so we do not have flat walking. it’s up or down in a hilly landscape. This is an area where people come on holiday to hike and do cross-country skiing.

I just have to walk 100m out of my front door and I am in a lovely place.

It is for me very relaxing, you can let your thoughts flow and I really enjoy to be outside because now with the Argus II, I can perceive the trees and grass where we walk – for example, I perceive sheep in the fields – I see the shape and movement of the sheep. I can see the contours of the land and the horizon and when I go outside with the dogs – I love to see them running around for fun.

I can guess the colours of the sky – what I like to look for in the sky is to see the difference between the sky and clouds. I can perceive the difference – it is so exciting for me. For someone who has normal vision, for me it is amazing to be able to see white clouds. There’s a different contrast between the cloud and the blue – it changes when I scan and I move my head. I can’t see colours but the cloud is a different shade of grey – I can see the difference.

I feel much happier that I can see the sky – so happy that I nearly cried – it’s so great to be able to do these things again. Not to be in the dark, to be hidden in your blindness – when you’re totally blind, you have a sense of being isolated.

I love to walk behind Peter so I can follow him – I follow his shape, I sense the movements of his legs. I hadn’t known Peter very long before I went totally blind: it’s a good feeling to see him again – I liked what I perceived!

I can’t see details of the landscape– but just because I know the area so well I know particular trees very well – if I am in a place I don’t know so well, I would not so exact. I can sense a tree – but perhaps not what type of tree. I love to see waves – that’s really amazing. I can hear, smell and perceive the sea now – it’s such a good feeling!”

“I am looking forward meeting Julian because I really think he’s a cool guy to do this big walk – and I am looking forward to seeing Cornwall, I am looking forward to coming back to the UK and enjoying nature, and talking to everyone on the Big Blind Walk.”