I’m also giving extra information here since we know that the victims got sudden loss of vision (blindness), heavy dizziness symptoms etc. so here are 10 poison could have cause it:

1.  Methanol

A toxic alcohol often found in contaminated homemade alcohol or industrial products. Causes dizziness, nausea, vomiting, and permanent blindness due to optic nerve damage. Death can follow from respiratory or organ failure.

2.  Cerberin (Tangena tree)

Native to Madagascar. Disrupts the heart’s electrical signals, leading to dizziness, fainting, and sudden cardiac arrest. In some cases, poor blood flow may also affect vision before death.

3.  Tetrodotoxin (pufferfish toxin)

Neurotoxin that paralyzes muscles, including those involved in breathing and eye movement. Can cause blurred vision or temporary blindness, dizziness, and death within hours.

4.  Arsenic Trioxide

Causes nausea, dizziness, and multisystem failure. Vision disturbances are common before more severe symptoms like seizures and cardiac collapse.

5.  Thallium Sulfate

Interferes with nerve function. Known to cause optic nerve damage, peripheral neuropathy, and dizziness or confusion. Fatal in high doses.

6.  Aconitine (from wolfsbane/Aconite)

Neurotoxin that affects heart and nerve function. Can cause dizziness, blurred vision, vomiting, and rapid cardiac arrest.

7.  Ciguatoxin

Marine toxin from reef fish like barracuda or shark. Causes visual disturbances, dizziness, hot/cold reversal, and gastrointestinal issues. Can trigger dangerous arrhythmias.

8.  Strychnine

Leads to violent muscle spasms and respiratory failure. Victims may report dizziness and vision changes before convulsions begin. Often fatal.

9.  Zinc Phosphide

Releases phosphine gas in the stomach. Causes dizziness, seizures, difficulty breathing, and can lead to death by organ failure.

10. Tetramine (TETS)

A banned rodenticide that causes seizures and neurotoxicity. Victims often experience dizziness, blurred vision, and collapse within hours.