Latanoprost Eye Drops: what it does and what to watch

Also known as: Prostaglandin analog eye drop, Glaucoma pressure-lowering drop · Prostaglandin analog eye drop · Updated 2026-08-20 · Educational — not medical advice

Illustrative — the eye, where fluid pressure builds in glaucoma

In plain language: This eye drop increases the outflow of the fluid that normally circulates inside the eye (aqueous humor), lowering the internal pressure that, if left high over time, can damage the optic nerve and threaten vision. It's used on a regular schedule set by a prescriber, and consistent use matters because glaucoma-related pressure damage develops silently without early symptoms.

What it's used for

  • Elevated pressure inside the eye
  • Open-angle glaucoma
  • Ocular hypertension

Common side effects

  • Eye redness
  • Stinging or burning right after the drop is applied
  • Temporary blurred vision
  • Itching
  • Gradual lengthening, thickening, or darkening of the eyelashes

Get medical help if…

Permanent darkening of the iris (the colored part of the eye), most noticeable in eyes with mixed brown-and-other coloring, which can be uneven if only one eye is treated

Darkening of the skin around the eyelid

Swelling of the macula (central retina) in people with certain prior eye surgeries or existing eye conditions

Worsening of existing eye inflammation (uveitis)

Eye infection if the dropper tip touches the eye or other surfaces

Lab values it can move

Few guides tell you this part: medicines show up in blood work. If you take Latanoprost Eye Drops and a value below looks off on your report, this may be part of the story — never stop a medicine without your doctor.

Routine blood tests are not typically needed to monitor this eye drop, since properly applied drops lead to only minimal absorption into the bloodstream.

Creatinine

Good to know

  • Notify an eye doctor about any history of eye inflammation, previous eye surgery, or retinal problems before starting this drop
  • Applying pressure at the inner corner of the eye for about a minute after each drop (nasolacrimal occlusion) can reduce the amount absorbed into the bloodstream and reduce systemic side effects
  • Be aware that eye color changes, once they occur, are usually permanent even if the drop is later stopped
  • Avoid letting the dropper tip touch the eye or eyelid to reduce contamination risk
  • If using more than one type of eye drop, space them apart as advised, since order and timing can affect absorption

Questions people ask

Will this eye drop permanently change my eye color?

It can. Some people, particularly those with hazel or mixed brown-and-green or blue eyes, notice a gradual darkening of the iris with long-term use, caused by increased pigment production in the iris. This change tends to be permanent even after stopping the drop, though it doesn't affect vision or eye health, and using it in only one eye can leave eye colors slightly mismatched.

What is nasolacrimal occlusion and why would I do it?

This means gently pressing a finger against the inner corner of the eye, near the nose, for about a minute after applying the drop. It slows drainage of the medicine into the tear duct and bloodstream, which keeps more of it working on the eye and reduces how much reaches the rest of the body, lowering the chance of systemic side effects.

Taking Latanoprost Eye Drops? See what your blood work says.

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