Prostaglandin eye drops are first-line treatment for glaucoma, helping lower eye pressure by increasing fluid outflow from the eye. They are usually taken once daily, are highly effective, and play a key role in slowing disease progression when used consistently, Dr Shibal Bhartiya explains.

Glaucoma is called the silent thief of sight for a reason. It rarely hurts. The vision loss it causes: slow, peripheral, irreversible, is not something you feel until it is far advanced. This silence is exactly what makes the most common patient mistake so dangerous: stopping prostaglandin eye drops because you feel fine.

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Dr Shibal Bhartiya is a fellowship-trained glaucoma specialist and Mayo Clinic Research Collaborator with over 25 years of experience. Her approach focuses on identifying risk before damage is irreversible, simplifying treatment decisions, and protecting vision long-term. Emphasis on early detection, risk assessment, and continuity of care. She is rated 5 stars across 1,500+ patient reviews on Google.

Known for her structured approach to glaucoma risk assessment and progression analysis, Dr Shibal Bhartiya provides trusted second opinions for patients seeking clarity before major treatment decisions.

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What Are Prostaglandin Analogues?

Prostaglandin analogues are the most widely prescribed first-line drops for glaucoma and ocular hypertension. The family includes latanoprost, bimatoprost, travoprost, and tafluprost. One drop, once a day, usually at night, and the intraocular pressure (IOP) comes down by 25 to 35 percent in most patients.

They work by increasing the outflow of aqueous humour through a pathway called the uveoscleral route, essentially opening a drainage channel that bypasses the conventional meshwork. The pressure falls, the optic nerve is protected, and vision is preserved. This mechanism makes them uniquely effective, and uniquely dependent on consistent daily use.

They do not cure glaucoma. They control it. The moment you stop, the protection stops with them.

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The Washout Problem: What Happens When You Stop

The term “washout” comes from clinical research. When scientists design drug trials, they ask patients to stop their current drops for a set period before the study begins, so the drug clears the eye and baseline measurements are accurate. This washout period for prostaglandins is typically four to eight weeks.

What researchers noticed, repeatedly, was that IOP did not simply return to its pre-treatment level during washout. In many patients, it climbed significantly higher. This is the rebound spike. It is not a curiosity. It is a clinical hazard, perhaps mediated by receptor upregulation.

This is not theoretical. Research on intraocular pressure dynamics confirms that pressure fluctuation, not just mean pressure, is an independent risk factor for glaucoma progression. A sharp peak does damage that weeks of good control cannot undo. My own published work examining IOP behaviour and treatment targets reinforces why pressure stability matters as much as the average reading. (Bhartiya et al., PMID 25081325)

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The Generic Question: Are All Prostaglandins Equal?

In India, the number of generic travoprost and latanoprost formulations available at any pharmacy is bewildering. Patients are switched between brands by chemists, or offered cheaper alternatives by well-meaning family members. The assumption is that the active molecule is the same, so the drops must be identical.

The evidence complicates that assumption.

Research published in the Journal of Current Glaucoma Practice, directly examined the physical properties of branded versus generic travoprost formulations available in the Indian market. The findings were striking: significant variation in drug concentration, osmolality, pH, and drop volume across different generic products, with some formulations falling outside accepted limits. (Wadhwani, Bhartiya et al., PMID 27536047)

A subsequent review I co-authored examined this question more broadly: the debate about branded versus generic glaucoma drugs is not merely academic. For a chronic, largely asymptomatic disease where adherence is already fragile and the consequences of under-treatment are invisible until serious, the choice of formulation matters. Cost matters too, glaucoma is often a lifelong condition, and expense is a real compliance barrier. But cost savings that come with inconsistent drug delivery are not savings at all. (Bhartiya and Dhingra, PMID 33367157)

The practical message: if your chemist substitutes your glaucoma drop with a different brand, tell your glaucoma specialist. Do not assume equivalence. Do not stop the drops while you investigate.

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Why Patients Stop, and What Actually Happens

The most common reasons I hear for stopping prostaglandin drops:

“My eyes looked red, so I stopped.“ Conjunctival redness and a mild burning sensation are common early side effects that usually settle within the first few weeks. Stopping the drops removes the side effect and removes the protection. The right response is to speak to your specialist, not to self-discontinue.

“I felt fine.” Glaucoma is asymptomatic. Feeling fine means nothing about your IOP or your optic nerve. By the time you feel something is wrong with your vision, damage has already happened, and it is permanent.

“I ran out and the chemist didn’t have the same brand.” Running out of drops is the single most common cause of medication gaps. It is also entirely preventable. Treat your glaucoma drops the way you would treat insulin: not as something optional when the bottle runs out.

“My eye pressure was normal at my last visit, so I thought I could stop.” This is perhaps the most understandable mistake, and the most dangerous one. The pressure was normal because the drops were working. Stop the drops, and the pressure rises again, sometimes dramatically. Normal pressure on medication is the goal of treatment, not evidence that treatment is no longer needed.

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What Happens During Surgery or Procedures?

There is one medically valid reason to pause prostaglandin drops: when your ophthalmic surgeon specifically instructs you to do so before a procedure. Prostaglandins can affect intraoperative results in certain situations, and the decision to pause them must come from your treating doctor, with a clear plan for the period of interruption.

Even then, the pause is carefully managed. Patients undergoing minimally invasive glaucoma surgery (MIGS) or trabeculectomy are monitored closely during any washout period precisely because of the pressure instability it can cause. The surgical approach for individual patients, including whether and how drops are adjusted, requires the kind of nuanced, personalised judgement that cannot be reduced to a general rule. (Bhartiya et al., PMID 31915728)

If you are not being prepared for surgery, there is no reason to stop your drops. None. Unless asked by your glaucoma specialist.

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Side Effects: The Ones Worth Knowing About

Prostaglandin analogues are well tolerated by most patients. But there are a handful of side effects worth discussing with your specialist, not because they should prompt you to stop the drops unilaterally, but because knowing about them means you can manage them properly.

Periorbital changes. Long-term use can cause deepening of the upper eyelid sulcus, mild ptosis, and orbital fat atrophy. These changes are collectively described as prostaglandin-associated periorbitopathy. These are more common with higher-concentration formulations and more likely with bimatoprost than with latanoprost or travoprost. They are not medically dangerous, but they are worth discussing if you notice changes in your appearance.

Iris pigmentation. In patients with mixed-colour irises (hazel, green-brown), prostaglandins can gradually increase melanin in the iris stroma, causing a permanent darkening. This change is irreversible but not harmful to vision.

Eyelash changes. Lengthening, thickening, and increased pigmentation of the eyelashes are a well-known effect. For some patients, this is a welcome side effect. For others, misdirected eyelash growth can cause irritation.

Cystoid macular oedema. Rare, but worth knowing. Patients who have had cataract surgery or uveitis have a slightly higher risk. Any new blurring of central vision in a patient using prostaglandins warrants prompt review.

All of these are manageable. None of them are reasons to stop drops without talking to your specialist first.

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The Generic Formulation Trap

I want to return to the question of generics, because it is particularly relevant in the Indian context.

A patient prescribed latanoprost 0.005% may be dispensed any one of a dozen formulations depending on what the pharmacy stocks that day. Most patients have no way of knowing whether the bottle they are using is the same drug at the same effective concentration as what they were prescribed.

The research is clear that not all generic formulations are equal in their physical properties, and that quality control in the production of generic ophthalmic formulations in India has historically been variable. This does not mean all generics are inferior. It means that an unexplained rise in IOP on a medication you have previously responded to should prompt a conversation about which formulation you are actually using.

If your drops were controlling your pressure and your pressure has risen, the drop may not have changed, but the bottle might have.

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A Note on Compliance: The Larger Picture

Glaucoma requires lifelong management. That is a long time to take a drop every evening without ever seeing any evidence that it is working: no improvement in vision, no symptom relief, nothing measurable in your daily life. The only evidence is a number on a machine in a clinic you visit every few months.

This is the fundamental challenge of glaucoma compliance. And the research confirms what every glaucoma specialist observes in clinic: adherence deteriorates over time, is worst in asymptomatic patients, and is closely linked to whether patients genuinely understand why the drops matter.

The drops matter because glaucoma is a progressive optic neuropathy: a disease of the nerve, not just the pressure. The pressure is the most modifiable risk factor we have. Lower the pressure consistently and you slow, or in many cases halt, the progression. Stop lowering it, even briefly, even unintentionally, and you give the disease an opening.

Every drop counts. Every evening. For as long as your specialist prescribes them.

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What to Do If You Have Missed Doses

If you have missed one or two doses, resume your drops that evening and continue as normal. Do not double-dose to compensate. One drop per eye per evening is the correct regimen regardless of what happened the night before.

If you have been off your drops for longer, a week or more, call your specialist for a pressure check. Do not wait for your next scheduled appointment. A brief gap is usually manageable, but it needs to be assessed, not ignored.

If you have run out and cannot access your usual formulation, contact your specialist’s clinic before switching to a different brand. The switch may be perfectly fine. Or not.

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When to Seek a Second Opinion

If you have been prescribed prostaglandin drops and you are uncertain why. If no one has explained what your pressure target is, what your optic nerve looks like, or what the risk of stopping your drops actually means for your specific situation: you deserve a thorough conversation. Glaucoma management is not one-size-fits-all.

Patients who come to me for a second opinion often arrive having made decisions about their medication based on incomplete information. They stopped drops that were controlling their disease. Switched brands without realising the implications. They were told their pressure was fine without being told that it was fine because of the drops.

Informed patients make better decisions. If your current care has not given you the information you need to protect your own vision, ask for it. Or find a specialist who will provide it.

Clinical Reality (What’s not always obvious)

• Not everyone responds equally—some patients need additional drops, laser, or surgery despite regular use.
• Redness, darkening of eyelids/iris, or lash growth can affect comfort and adherence.
• Missing doses matters—these drops work best with consistent, long-term use.
• More medications ≠ better control; the goal is stable optic nerve over time, not just a lower number on one visit.

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6. Quick Summary Table

Aspect	What It Means for You
Role in treatment	First-line drops for most patients with glaucoma
How they work	Increase fluid outflow → lower eye pressure
Dosing	Usually once daily (often at night)
Effectiveness	Strong pressure reduction in most patients
Common side effects	Redness, irritation, eyelash growth, periocular skin darkening
Long-term changes	Possible gradual iris color darkening (cosmetic, not harmful)
When not enough	May need additional drops, laser (SLT), or surgery
Adherence importance	Irregular use reduces protection against progression
Big picture	Helps slow damage—but needs monitoring, not blind continuation

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Frequently Asked Questions

What are prostaglandin analogues and how do they lower eye pressure?

Prostaglandin analogues are the most commonly prescribed first-line eye drops for glaucoma. They include latanoprost, bimatoprost, travoprost, and tafluprost. They work by increasing the drainage of fluid from the eye through the uveoscleral pathway, reducing intraocular pressure by 25 to 35 percent in most patients. These drops are used once daily, typically at night.

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What happens if I stop my glaucoma eye drops suddenly?

When you stop prostaglandin drops, the pressure-lowering effect wears off and your intraocular pressure rises again, often higher than your original baseline. This is called a rebound IOP spike. Because glaucoma damages the optic nerve silently, this pressure rise causes harm before you feel anything. Even a brief gap in treatment can accelerate nerve fibre loss that cannot be reversed.

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Is it safe to stop glaucoma drops if my eye pressure is normal?

No. Your pressure is normal because the drops are working. Stopping them removes the treatment, not the disease. Glaucoma is a chronic condition that requires lifelong pressure control. Normal pressure on medication means the medication is doing its job, not that you no longer need it.

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Can I switch between generic and branded prostaglandin drops?

Not without consulting your glaucoma specialist. Research has shown significant variation in drug concentration, osmolality, and drop volume between different generic prostaglandin formulations available in India. If your chemist substitutes your usual brand, inform your doctor and have your pressure checked. An unexplained rise in IOP while on medication may be related to a formulation change.

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What are the common side effects of prostaglandin eye drops?

Most patients tolerate prostaglandin drops well. Known side effects include mild redness and irritation (usually temporary), gradual darkening of the iris in patients with mixed-colour eyes, eyelash lengthening and thickening, and periorbital changes such as deepening of the upper eyelid crease with long-term use. Rare side effects include cystoid macular oedema, particularly in patients with a history of cataract surgery or uveitis. None of these are reasons to stop drops without first speaking to your specialist.

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What should I do if I miss a dose of my glaucoma drops?

Resume your drops that evening and continue as normal. Do not use two drops to make up for the missed dose. The correct dose is one drop per eye per evening regardless. If you have missed drops for a week or more, contact your specialist for a pressure check rather than waiting for your next scheduled appointment.

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Do I need to stop my glaucoma drops before eye surgery?

Only if your surgeon specifically instructs you to. There are situations, certain glaucoma and cataract procedures, where prostaglandin drops are paused before surgery. This decision must come from your treating doctor, with a clear plan for monitoring your pressure during any gap. If no one has told you to stop your drops, keep using them.

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Why do my eyes look different after years of using glaucoma drops?

Long-term use of prostaglandin analogues can cause periorbital changes, including deepening of the upper eyelid sulcus, mild drooping of the eyelid, and loss of orbital fat. These changes are more noticeable with bimatoprost than with latanoprost or travoprost. They are not medically harmful but are worth discussing with your specialist if you notice them. Switching to a preservative-free formulation or a different molecule may reduce these effects.

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Are prostaglandin drops safe for long-term use?

Yes, for the vast majority of patients. Prostaglandin analogues have a well-established long-term safety profile and are the global standard of care for first-line glaucoma treatment. The risks of stopping them, uncontrolled IOP and progressive optic nerve damage, are far greater than the risks of continuing them under specialist supervision.

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When should I seek a second opinion about my glaucoma treatment?

Seek a second opinion if you do not understand why a particular drop has been prescribed, what your target pressure is, or what the risk of stopping your medication actually means for your specific optic nerve and disease stage. Patients who arrive for a second opinion often discover they have been making decisions, including stopping drops, based on incomplete information. Informed patients protect their own vision better. A thorough explanation of your diagnosis and treatment plan is not optional; it is part of good glaucoma care.

Read the research articles

This article was written by Dr Shibal Bhartiya, fellowship-trained glaucoma specialist and Mayo Clinic Research Collaborator, Clinical Director at Marengo Asia Hospitals, Gurugram, known for ethical, patient-centred glaucoma care and independent glaucoma second opinions. She is also the Program Director for Community Outreach & Wellness; and for the Marengo Asia International Institute of Neuro and Spine,. This article was edited in April 2026.

She has published peer-reviewed research on glaucoma management, examining how treatment decisions should balance medical evidence, patient preferences, and long-term vision outcomes.

As Editor-in-Chief of Clinical and Experimental Vision and Eye Research and Executive Editor of the Journal of Current Glaucoma Practice (Pubmed Indexed, official journal of the International Society of Glaucoma Surgery), Dr Shibal Bhartiya brings editorial and research depth to every clinical decision. Her 200+ publications, including 90+ PubMed-indexed publications and 28 edited textbooks span glaucoma biology, surgical outcomes, health equity, and emerging diagnostics.

Access her work on Pubmed, Google Scholar, ResearchGate and ORCID.

Dr Shibal Bhartiya
Glaucoma • Second Opinion • Advanced Care

www.drshibalbhartiya.com
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