Why Clear Vision in One Eye but Blurry with Both? Eye Issues

Clear vision with one eye but blurred vision with both eyes?

Hello Doctor, my father suddenly experienced blurred vision and dizziness last week.
He visited an ophthalmology clinic where the doctor diagnosed him with severe dry eye syndrome and prescribed eye drops.
He then went to the neurology department at Veterans General Hospital for a neck and head ultrasound (the report will be available next week) and also underwent retinal laser treatment in the ophthalmology department (the doctor mentioned that my father's retina is too thin).
He also checked his liver function and blood sugar levels, both of which were normal.
My father is currently 60 years old and has hypertension, for which he takes medication regularly.
He now reports that when he looks with one eye at a time, his vision is clear, but when he uses both eyes together, it becomes blurry, and he still feels dizzy.
I would like to inquire about what might be causing this issue and what additional tests may be needed.
Thank you for taking the time to respond.

Xiao Xiao Lai, 20~29 year old female. Ask Date: 2016/03/30

Dr. He Jianxian reply Ophthalmology

It is recommended that you go directly to an ophthalmology clinic to address this issue and have it examined by an ophthalmologist, as it is not possible to determine the problem based solely on text.

Reply Date: 2016/03/30

More Info

Hello,
Thank you for your detailed inquiry regarding your father's vision issues. Based on the information provided, it seems that your father is experiencing a complex set of symptoms that could be attributed to several underlying factors. Let's break down the situation to better understand the potential causes and necessary steps for further evaluation.

Understanding the Symptoms
1. Clear Vision in One Eye but Blurry with Both: This phenomenon can occur due to several reasons. When one eye is functioning well while the other is not, the brain may struggle to combine the inputs from both eyes, leading to a blurry perception when both are used together. This can be particularly pronounced if there is a significant difference in vision quality between the two eyes, a condition known as anisometropia.

2. Dry Eye Syndrome: Your father's diagnosis of severe dry eye syndrome could be a significant contributor to his symptoms. Dry eyes can lead to fluctuating vision, especially when both eyes are used together. The lack of adequate tear film can cause the visual clarity to diminish, particularly during prolonged use of the eyes, such as reading or using screens.

3. Headaches and Dizziness: These symptoms can be associated with visual disturbances. If the eyes are not working in harmony, it can lead to eye strain, which may manifest as headaches or dizziness. Additionally, if there are underlying neurological issues, such as those that might be indicated by the ultrasound, they could also contribute to these symptoms.

Potential Causes
- Refractive Errors: If your father has uncorrected refractive errors (like myopia, hyperopia, or astigmatism), this could lead to blurred vision when both eyes are used together. A comprehensive eye exam can determine if his current prescription is adequate.

- Retinal Issues: Given that your father has undergone retinal laser treatment due to a thin retina, it is crucial to monitor for any changes in the retina that could affect vision. Conditions such as retinal detachment or macular degeneration could lead to significant visual disturbances.

- Neurological Factors: Since your father is experiencing dizziness and has undergone a neck ultrasound, it’s essential to consider whether there are any neurological factors at play. Conditions affecting blood flow to the brain or issues with the optic nerve could also contribute to these symptoms.

Recommended Actions
1. Follow-Up with Eye Care Professionals: It is vital for your father to have a thorough follow-up with both his ophthalmologist and possibly a neurologist. They can evaluate the results of the ultrasound and any other tests that may be necessary.

2. Comprehensive Eye Exam: A complete eye examination, including refraction tests, retinal imaging, and possibly visual field testing, can help identify any refractive errors or retinal issues that may be contributing to the blurry vision.

3. Dry Eye Management: Since dry eye syndrome is a significant factor, ensuring that your father is using the prescribed eye drops correctly and considering additional treatments (like punctal plugs or prescription medications) may help improve his symptoms.

4. Monitor Symptoms: Keeping a diary of when the symptoms occur, their duration, and any associated activities can provide valuable information for healthcare providers.

5. Lifestyle Modifications: Encourage your father to take regular breaks during activities that require prolonged visual focus, stay hydrated, and maintain a healthy diet to support eye health.

Conclusion
In summary, your father's symptoms of clear vision in one eye but blurry vision when both are used together can stem from a combination of dry eye syndrome, refractive errors, and possibly underlying retinal or neurological issues. It is essential to pursue further evaluations and follow up with healthcare professionals to address these concerns comprehensively. Early intervention can significantly improve outcomes and quality of life.

Thank you for reaching out, and I hope your father finds relief and clarity soon.

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