This is one of my favorite cases because it was a patient I had right after coming out of Optometry school in Israel where Optometry has no diagnostic nor treating rights regarding ocular disease, meaning no dilation, no IOP check etc. Keep in mind, as you read that case, that standard of care over there is different. Enjoy!
A 17-year-old asymptomatic male presented for his driving license visual examination. He was healthy and a contact lens wearer.
Upon testing on the “Titmus” driver’s license machine (see image below) which is similar to the US DMV vision test, the patient passed the visual acuity test of 20/40 but it was somehow suspicious.
Likewise, the visual field testing which consisted of blinking lights in different peripheral locations (see image below) was also good enough to pass the test but the patient was hesitant when answering. Something was off.
This patient was a walk-in, the practice was hectic at that moment and it was my first week at this particular location. I took a moment to do an undilated direct ophthalmoscopy. Surprisingly, the patient had a PSC cataract OD>OS (reminding that the patient is 17 y/o). The margin of his optic nerves did not look sharp OU but his macula was unremarkable in both eyes.
I had the patient return at the end of my shift for a complete examination. Old records showed a myopia of -3.50 OU five years ago which increased by 1.00D per year with associated decreasing visual acuity. Today’s exam revealed a refraction of -8.50 and VA of 20/40 in both eyes. The anterior segment was unremarkable outside of the PSC cataracts.
As mentioned above, dilation is not permitted for Optometrists in Israel however a fundus camera was available. I saw the pictures and almost fell off my chair, see the images below.
Note the patchy and coalescent mid-peripheral atrophic spots with scalloped borders.
This is a pathognomonic presentation for a rare genetic condition I have learned about in Optometry school called Gyrate Atrophy.
The patient was referred to the retinal specialist to confirm the diagnosis.
I had the Ophthalmologist on the phone before his examination and told him it looks like “Gyrate Atrophy”, he started laughing knowing the rarity of the condition but after his examination, the diagnosis was confirmed, it was indeed Gyrate Atrophy. A visual field and OCT were performed on that day, see below:
Note the visual field loss at the edges in both eyes.
Note the macular edema in the right eye (top image) and the atrophic outer retina AND choroid on the scan performed through the peripheral lesions (bottom image)
Discussion:
Gyrate Atrophy of the Choroid and the Retina affects less than 1 person in a million, it is more prevalent in Finland where it affects 1 in 50,000 individuals.
Gyrate Atrophy in a nutshell:
– A mutations in the OAT gene causes Gyrate Atrophy (Autosomal Recessive)
– It results in a reduced amount of functional ornithine aminotransferase enzyme which is responsible for the breakdown of Ornithine, an amino acid found in meat, fish, dairy, and eggs.
– Excess ornithine accumulates in the blood which is toxic to the retina and causes this atrophic pattern.
Other associated findings are PSC cataract, increasing myopia, reduced visual acuity, night blindness, and macular edema.
– The name Gyrate Atrophy comes from the appearance of the scalloped lesions that resemble the gyri of the brain.
Gradual vision loss typically starts around age 10 followed by the appearance of these mid-peripheral lesions. The Prognosis is poor and these patients typically reach legal blindness by age 40 to 70. A small number of these patients respond to Vitamin B6 supplements.
This patient will most likely experience progressive vision loss but treatments including a diet avoiding food rich in ornithine and intake of vitamin B6 may slow down the process. Early diagnosis is key in these patients.
I will not forget my first week at this practice and most importantly how my career started in a country where diagnosing ocular disease is extremely difficult due to the poor spectrum of practice in Optometry.
I hope you enjoyed this case and I’ll see you guys next month!
