Choroidal Neovascularization

SerendipUpdate's picture

Biology 103
2003 First Paper
On Serendip

Choroidal Neovascularization

HoKyung Choi

If you had to give up one of your five senses, which would it be? Would you give up your ability to see? A startling number of people lose their eyesight due to an eye disorder known as choroidal neovascularization. And soon I may be one of them. Although there is no known cure for this unfortunate disease, studies have been conducted to find the appropriate surgical treatment.

The outer portion of the 2.5 cm human eye is composed of three primary layers of tissue. The outermost layer is called the sclera, which acts as a protective coating. Within this layer the transparent cornea is present in the front area of the eyeball. Under the sclera is the choroid where the majority of blood vessels and the iris are located. The light-sensitive layer is known as the retina.

As mentioned, the choroid contains most of the eyeball's blood vessels. It is also the layer prone to bacterial and secondary infections. Choroidal neovascularization is a process in which new blood vessels grow in the choroid, through the Bruch membrane and invade the subretinal space. Because there is currently no medical treatment for this disease this abnormal growth can easily lead to the impairment of sight or complete loss of vision.

Three main diseases that cause choroidal neovascularization are age-related macular degeneration, myopia and ocular trauma. The Wisconsin Beaver Dam Study showed that 1.2% of 43-86 year old adults with age-related macular degeneration developed choroidal neovascularization. The study also proved that choroidal neovascularization was caused by myopia in 5-10% of myopes. Ocular trauma, another cause of choroidal neovascularization, is for reasons unknown found more often in males than females. More than 50 eye diseases have been linked to the formation of choroidal neovascularization. Even though most of these causes are idiopathic, among the known causes are related to degeneration, infections, choroidal tumors and or trauma. Among soft contact lens wearers choroidal neovascularization can be caused by the lack of oxygen to the eyeball. Unlike age-related macular degeneration, age is irrelevant to this cause.

Although no medical treatments have proven to be a cure for choroidal neovascularization, particular antiangiogenic substances such as thalidomide, angiostatic steroid, and metalloproteinase inhibitors are currently being tested. Through surgical testing, partial removal of choroidal neovascularization proved to be useless. Therefore the focus has been placed on photodynamic therapy, a procedure approved by the Food and Drug Administration.

In choroidal neovascularization patients, the fluid and blood along with the formation of new blood vessels form scar tissues which are trying to repair damages but are ultimately the cause of blindness. Photodynamic therapy is a treatment meant to stop the fluid as well as stunt further growth of the blood vessels among patients. Photodynamic therapy is performed in two phases. In the first phase Visudyne, a special dye that only attaches itself to abnormal blood vessels underneath the retina, is injected. Then a laser which does not damage the retina activates a compound which closes the anomalous blood vessels located in the eye. CNV has been seen to disappear 24 hours after the procedure. Unfortunately, CNV has also been seen to reappear 2-3 months later in almost all the patients and long-term benefits are still unknown. However, in a year-long Treatment of Age-related Macular Degeneration study of 609 patients16% of treated patients and 7% of placebo patients had visual improvement.

Another type of treatment that is being tested in a study called the Submacular Surgery Trials is an experimental procedure known as submacular surgery. This procedure is performed from the inside of the eye in order to work on the retinal tissues to remove and replace the vitreous fluid. The downside of this procedure is that in order to heal the patient must be face-down for several weeks after the fluid is replaced.

It is most unfortunate that there is still no effective medical treatments nor any completely successful surgical treatments because I was recently diagnosed with choroidal neovascularization in both of my eyes. Although the knowledge I have gained by researching this disease has been personally enlightening, the facts are frightening as well. But to remain optimistic, it is somewhat comforting to know that there are studies such as the Wisconsin Beaver Dam Study and the Submacular Surgery Trials working towards a cure.

 

References

1) Unified Medical Language System, Medical term dictionary
2) Submacular Surgery, Information about submacular sugery
3) The Royal College of Ophthalmologists, Information about photodynamic therapy
4) Barnes Retina Institute, Education website on photodynamic therapy
5) Ocular Photodynamic Therapy for Choroidal Neovascularization, Description of ocular photodynamic therapy
6) Eye (anatomy), Explanation and overview of the eyeball
7) eMedicine, Journal article on subretinal neovascular membranes
8) eMedicine, Journal article on choroidal neovascularization

 

 

Comments made prior to 2007

Hi! i'm Abie from the Philippines. I just saw your website when I was doing a research about choroidal neovascularization. My dad currently has this optical problem, and the doctor said that he has to undergo a certain operation called Vitrectomy. The problem is, during the operation, there is 2% chance that he'd get blind. I know that's it's just a very small chance but still, we are scared of the consequences of this operation. Is there anything that we can do to avoid that? What medicines can he take? I hope you can help me with this. Thanks! ... Abie, 4 April 2006

Comments

Anonymous's picture

CNV

I was just diagnosed a few days ago with CNV in one eye and will have an initial Lucentis injection next week. If the injection doesn't work, what's the next step ?

Anonymous's picture

CNV

I am a research coordinator for a retina doc and am currently involved in a study which is comparing Avastin and Lucentis in a head to head trial. It is called the CATT Study. Avastin (used off label for the treatment of CNV) and Lucentis which is and FDA approved drug are the two most effective treatments available at this point (for most cases of CNV). The most effective treatment schedule is still unkown, most ophthalmologist have started treating PRN but the research data on Lucentis was obtained by giving monthly injections. For patients with newly diagnosed CNV, I suggest you read up on both drugs and the different treatment plans. The CATT Study is a two year trial so we hope to have more information about these two drugs in the near future.

Sue's picture

Lucentis

I am about to have my first Lecentis injection on Friday April 24 2009 and wondered if you had found more information on the CATT study. I have CNV in my left eye onlyand I am 64, a woman, and have had previous trouble with that eye, ie partical retina detachment and cataract... thanks for any further comments.

CharleyElizabeth's picture

Choroidal Osteoma

I'm 18 and the doc thinks I have Choroidal Osteoma in one eye. I go to a specialist tomorrow. I'm scared.

anna's picture

RE:eyes

Hi,
Don't be scared. I am 32 and was diagnosed with Central serous retinopathy in 2004. I lost the central vision in left eye and right eye is 20/70. But i am hanging in there and prayer helps to. I will pray for you, and have faith in God.
God is always there for you when you need him.LOL.

Oli's picture

Thanks

Thank you for your information; last year I was diagnosed with this condition and I have forwarded your link to some friends to help understand what I am going thru; so i just wanted to say thank you for posting the information. Best of luck with your situation.

Anonymous's picture

There is treatment now!

You may already know this, but... there IS a treatment for this condition. My mother in law, who lives in Raleigh, NC, has this same problem in one eye. Her doctor is giving her injections, directly into the eye. It is DISSOLVING the vascularization. Best wishes!

Anonymous's picture

CNV treatment

My wife recently was diagnosed with CNV in her left eye. What is the name of the drug she's being injected with? What is her doctor's name? How long has your mother in law had the disease?

Anonymous's picture

chorodial neovascularization in a teenager

My daughter is a young healthy teenager just suddenly diagnosed with this disease. No prior eye issues/or health problems and started with avastin therapy though not much improvement, any suggestions or specialists/hospitals to think of a visit

Kim's picture

choroidal neovasculization

I am a 33yr old woman w/2 small kids who was just diagnosed with this in my left eye. I had my first Avastin injection 5 days ago. Just curious if you daughter has it in both or just one eye and how the improvements have been? Also, has your opthalmologist been able to give any indication of long term results or chances of it starting in other eye?

I would be most gracious for any response on this matter.
Thank you,
Kim

Tracey's picture

eye condition

Hi
I also have the condition in my left eye had it since i was 35yrs old now just turned 40 im intgerested in your injection i only had the photodynamic yellow stuff put in me, has it helped any as i find my sight deteriating in my left eye still have 20/20 vision in my right eye.
Thanks
Tracey

Kimberly's picture

Tracey- The avastin

Tracey- The avastin injections I had over the course of the years seemed to completely stop the blood vessels from leaking fluid. I have had no deterioration or reaccurances for 1 year and a half. How is you left eye now? Did you ever get shots? My right eye is still 20/20. Kim

Jan's picture

Choroidal Neovascularization

I had my first injection of Avastin on 9/18/2008. I will have another injection October 30 and then another six weeks after that. I had old scarring from a fungal infection years ago and that it what has caused te CNV now. I am being treated by a retina spectialist at the University of Iowa, Iowa City IA

lens's picture

Research

i am researching on choroidal neovascularization and try to develop a treatment modal.Especially photodynamic therapy is very useful and it can be developed more.

Post new comment

The content of this field is kept private and will not be shown publicly.