Can High Myopia Cause Enlarged Blind Spots and Visual Shadows?

Q: Can High Myopia Cause Enlarged Blind Spots and Visual Shadows?

Hello： <br>1. <br>High myopia and the expansion of the blind spot associated with high myopia (1000 and 1200 diopters) can indeed lead to retinal degeneration, which may affect the structures surrounding the optic nerve, resulting in an enlarged blind spot. <br>Although your OCT

Does high myopia cause an expansion of blind spots? + Visual shadows in dimly lit areas?

Hello Doctor, I have a few questions I would like to ask.

1.
I noticed in the past year or two that when I close one eye, I can see a dark area near my blind spot in both eyes.
Previously, I consulted a doctor who suggested it might be due to degeneration from high myopia.
I have undergone dilation and OCT scans of my retina and optic nerve, and the doctor said my optic nerve is fine.
Could high myopia (1000 and 1200 diopters) potentially cause an expansion of the blind spot? Given that the OCT scan of the optic nerve is normal, is it possible that this could be glaucoma?
2.
In the past year or two, I have also noticed that when I first get up and stay in a dimly lit area, or when I move from a bright area to a dim one, I experience some shadows at the edges of my vision for a while.
It feels like those areas are slower to respond to light.
However, when I am in well-lit areas, I do not have any particular sensations.
I remembered that my mother has retinitis pigmentosa (she seemed to have developed it quite young and has maintained tunnel vision, with no deterioration in her visual field until she turned 70).
I looked up my symptoms and they seem somewhat similar, but I have been regularly checked by an ophthalmologist due to previous issues with macular hemorrhage, including dilation, OCT, and fundus photography.
I visited an ophthalmologist yesterday who performed an OCT scan of my retina and optic nerve, but the doctor did not specifically mention this issue.
Can retinitis pigmentosa be detected through these tests? Currently, my night vision is fine, and I do not have symptoms of night blindness.
After discussing with the doctor yesterday, I have been scheduled for a visual field test in two months, but I would still like to understand what might be causing these conditions.
Thank you, Doctor!

O, 40~49 year old female. Ask Date: 2024/07/30

Dr. Gao Pilin reply Ophthalmology

Hello:
1.
High myopia and the expansion of the blind spot associated with high myopia (1000 and 1200 diopters) can indeed lead to retinal degeneration, which may affect the structures surrounding the optic nerve, resulting in an enlarged blind spot.
Although your OCT scan shows a normal optic nerve, patients with high myopia should still undergo regular examinations to monitor for potential changes.
Regarding glaucoma, even if the OCT scan indicates a normal optic nerve, there is still a possibility of glaucoma risk, especially in high myopia patients.
The diagnosis of glaucoma requires a comprehensive assessment that includes visual field testing, intraocular pressure measurement, and evaluation of the optic nerve.
The visual field test you are about to undergo will provide more valuable information.
2.
Visual shadows in dim light: The black shadows you describe at the edges of your vision in low light may be due to differences in light adaptation.
The retina of high myopia patients may be thinner, and the response time of photoreceptors may be slower, leading to transient visual disturbances during changes in lighting.
Regarding retinitis pigmentosa, this condition typically affects night vision (nyctalopia) early on and gradually leads to constriction of the visual field.
Although you currently do not have symptoms of night blindness, it is important to remain vigilant due to your family history and suspected symptoms.
Retinitis pigmentosa may show retinal pigment changes during ophthalmic examinations (including OCT and fundus photography), but sometimes more specialized tests are needed for diagnosis.
Recommendations:
1.
Visual field testing: This will help assess your peripheral vision status and rule out the possibility of visual field defects.
2.
Regular examinations: Due to the risks associated with high myopia, it is advisable to have regular ophthalmic check-ups to monitor the health of the optic nerve and retina.
3.
Intraocular pressure monitoring: Regular measurement of intraocular pressure to rule out the risk of glaucoma.
Wishing you good health.

Reply Date: 2024/07/30

More Info

High myopia, defined as a refractive error greater than -6.00 diopters, can indeed lead to various ocular complications, including the enlargement of blind spots and the perception of visual shadows. This condition is associated with structural changes in the eye, particularly in the retina and vitreous body, which can result in a range of visual disturbances.

1. Enlarged Blind Spots: In individuals with high myopia, the elongation of the eyeball can lead to stretching of the retina. This stretching can cause degenerative changes, particularly in the peripheral retina, which may contribute to the enlargement of blind spots. The presence of myopic degeneration, such as lattice degeneration or atrophic changes, can further exacerbate this issue. While your OCT scans have shown normal optic nerve health, it is essential to understand that glaucoma can still occur in myopic patients, albeit less commonly. Regular monitoring of intraocular pressure and visual fields is crucial to rule out any potential glaucomatous changes.

2. Visual Shadows: The phenomenon of experiencing shadows or dark spots, especially in low-light conditions or after transitioning from bright to dim environments, can be attributed to several factors. In high myopia, the vitreous gel can undergo liquefaction and detachment, leading to the perception of floaters or shadows. Additionally, the retina may have areas of reduced sensitivity due to myopic degeneration, which can manifest as transient visual disturbances when adapting to different lighting conditions.

3. Retinal Conditions: Given your family history of retinitis pigmentosa, it is prudent to consider the possibility of hereditary retinal conditions. While your recent examinations, including OCT and fundus photography, did not indicate any immediate concerns, it is essential to remain vigilant. Retinitis pigmentosa typically presents with specific patterns of retinal degeneration, which can sometimes be subtle in early stages. Genetic testing and further specialized imaging may be warranted if there is a strong suspicion based on family history.

4. Regular Monitoring: Your proactive approach in scheduling follow-up appointments and visual field tests is commendable. Regular monitoring is vital for individuals with high myopia, as it allows for the early detection of any changes that may require intervention. It is also advisable to maintain open communication with your ophthalmologist regarding any new symptoms or changes in your vision.

5. Lifestyle Considerations: Managing your eye health also involves lifestyle modifications. Adequate lighting when reading or using screens, taking regular breaks to reduce eye strain, and protecting your eyes from UV exposure are essential practices. Additionally, maintaining a healthy diet rich in antioxidants can support overall retinal health.

In summary, while high myopia can lead to visual disturbances such as enlarged blind spots and shadows, regular eye examinations and monitoring are crucial in managing these symptoms. If you continue to experience significant changes in your vision or have concerns about specific conditions like retinitis pigmentosa, seeking a second opinion or further specialized testing may provide additional peace of mind. Always prioritize your eye health and stay informed about the potential implications of high myopia.

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