Wednesday, February 8, 2023

Health update: vision

It feels a bit excessive to devote a blog post to this health update, but this post is a nice place for me to compile all the info I have  and answer as many questions for my mom as possible in one place (love you mom!). This update isn't nearly as life altering as the last time I did this, but the implication are made more severe because of the existing vision loss from my brain surgery. In short, this past December I developed a blurry/blind spot in my vision following a high fever from the flu, and was ultimately diagnosed with a rare condition called Acute Macular Neuroretinopathy in my right eye. This is non-life threatening, but there is no treatment and the associated vision loss is likely permeant. God is good, and in control!

{ Acute Macular Neuroretinopathy }
Acute: localized to one spot, not widespread
Macular: location of the eye
Neuroretinopathy: any disease that affects the retina and the optic nerve

Acute macular neuroretinopathy (AMN) is a rare condition in which you suddenly develop blurry or small blind spots in one or both eyes. For me, this condition is only affecting my right eye (more on that below). The blurry/blind spots are caused by lesions in the deep layers of your eye that can only be seen using imaging technology. My recent scans and images confirmed my diagnosis of this condition.

My lesion circled in red

The condition was first described in 1975; the medical community is still unsure exactly what causes these lesions to appear or how to treat them. AMN affects less than 1 in 1 million people, according to recorded cases. 

The most common symptom of AMN is blurry or blind spots in your eye – known in the medical community as paracentral scotomas – that are just off the center of your direct line of vision. Some people also report flashes that appear and quickly disappear and/or floaters, both of which I had on the days I first noticed the change in my vision. Some people develop the paracentral scotoma(s) a day or two after having flu-like symptoms – this was my exact experience.

Example of size and location of a paracentral scotoma caused by AMN.
This is almost exactly representative of mine.

Examples of how paracentral scotomas can present in the vision.
Mine alternates between the bottom two pictures.

Doctors are unsure what causes the lesions and paracentral scotomas of AMN, but up to half of people with AMN were reported to have had flu-like illnesses before their diagnosis. That's me! I had the flu leading up to my new missing vision spot culminating with a 106 degree fever the day directly before the vision loss occurred. Currently researchers believe that the body's response to some viruses may trigger issues with your circulatory (vascular) system and blood flow. This results in less blood supply to some parts of your body, including the eye and retina.

AMN has most often been reported in white women who are young to middle-aged, particularly those in their 30s. That’s me! Unfortunately, doctors don't know of any medicines or treatments to help with the condition. In some cases, the paracentral scotomas improve on their own over several months but full resolution of a scotoma from this condition has never been reported.

{ implications }
For most people, because the scotomas do not cause major vision loss. Unfortunately, I'm coming into this condition with two pre-existing visual complications that make the impact of AMN more pronounced for me.

1) I have a 25% loss of my total vision field from my brain surgery/stroke. That vision loss is located in my bottom left vision quadrant in both eyes.
My vision field loss from brain surgery is shown in black. 

2) My right eye is my main seeing eye. I was born with a cataract in my left eye, had it removed during my childhood, and then had an intraocular lens (IOL) put in during my 20s. Prior to the IOL surgery my left eye had 20/400 vision and my brain all but ignored anything the left eye "saw" because it was so different from what my right eye was seeing. The IOL surgery in my left eye placed a silicon lens into the left eye to prevent it from going lazy from non-use, and improved the vision in that eye to 20/200. My brain continues to use what my right eye sees as my main vision, with peripheral vision assist from my left eye. Because of my already compromised vision, having new missing vision in my right eye affects me more than someone with 20/20 in both eyes and full vision field in tact.

I can still drive, because all off the cumulative vision loss is located below my horizontal vision axis. I choose not to drive at night and/or in the rain because I want to err on the side of caution. I can still read. The paracentral scotoma still flashes whenever I blink, so it's distracting to me. I assume my brain will eventually get used to that and I'll notice it less over time.

{ timeline }

December 13, 2022: I was sick with a bad case of the flu, and this day my fever reached 106 degrees before we were able to successfully get it under control. 

December 14, 2022: I noticed a new bright spot in my vision, similar to a camera flash effect. The spot was about the size of a pencil eraser head, located SE of my central vision access. This is an area of my vision field that has not been compromised by my cavernoma/brain surgery/stroke. 

December 15, 2022: the bright spot remained the same size, but changed to squiggly black lines. in the following days the lines went away and were replaced with a smudge/blur blocking my vision within the spot. At this point, I decided to wait to see my eye doctor until after Christmas because 1) we were still recovering from the flu, and 2) if I was going to get bad news I just wanted to wait until after Christmas and enjoy the holidays with my family.

December 28, 2022: I went to see my eye doctor. This is the same doctor that helped with my prior cavernoma diagnosis. He was nervous for what we might find this time, given my previous history with vision loss led to the discovery of a vascular brain tumor. Thankfully the field vision test revealed the missing spot in my vision this time was limited to my right eye, which means this was almost certainly nothing to do with my brain. Further examination of my eyes revealed physical evidence of damage to my right eye retina. At this point, he gave me a temporary diagnoses of Posterior Vitreous Detachment and referred me to a retina specialist for further examination. 

January 10, 2023: Met with a retina specialist/optometrist at a clinic that is familiar to me due to my left eye cataract history. After scans and tests, the optometrist presented me with a different diagnosis: Acute Macular Neuroretinopathy (AMN). 

February 7, 2023: Follow-up appointment to confirm diagnosis, and check for improvement. Diagnosis was confirmed: I am the poster child for this rare, uncommon retina condition (this condition is apparently so rare that my optometrist intends to present it at an upcoming conference...lucky me?). While my retina damage showed improvement at this visit, unfortunately the paracentral scotoma in my vision field remains the same. I will continue with periodic follow-ups to track the healing of the retina and report on the paracentral scotoma, but we are not expecting much improve with my new missing vision spot. 

Retina damage improvement: top was early January, bottom was early February.

{ summary }
I had the flu, and my high fever caused very rare damage to the retina of my good eye, further complicating my overall vision. There is no treatment, and little-to-no evidence that the new missing vision will resolve even as the retina heals. Life will go on for me as normal, with a little less vision and a lot more belief that the Lord gives, and the Lord takes away. Blessed be the name of the Lord!

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