Sodium Cromoglycate (Cromolyn) is an anti-allergy eye drop used to prevent allergic eye conditions like Vernal Keratoconjunctivitis (VKC) and chronic allergic conjunctivitis.
| Drug class | Mast Cell Stabiliser |
|---|---|
| Type | Single |
| Forms | Eye Drop |
| Common strength | 2% / 4% |
| Common Indian brands | Cromal, Cromal Forte |
| Prescription status | Prescription |
What Sodium Cromoglycate (Cromolyn) is used for
Sodium Cromoglycate (Cromolyn) eye drops are a type of anti-allergy medicine prescribed to prevent certain eye conditions that are caused by allergies. This medicine works best when used regularly to stop allergic reactions from starting in your eyes.
- Vernal Keratoconjunctivitis (VKC): This is a severe, recurring allergic eye condition that primarily affects children and young adults, often during warmer months. It can cause significant discomfort, itching, redness, and sensitivity to light. Sodium Cromoglycate helps prevent the allergic inflammation associated with VKC.
- Chronic Allergic Conjunctivitis: This refers to long-lasting or frequently recurring allergic inflammation of the conjunctiva (the clear membrane covering the white part of your eye and the inside of your eyelids). Sodium Cromoglycate is used as a preventive therapy to reduce the frequency and severity of these allergic episodes.
It is important to remember that this medicine is for preventing allergic reactions, not for treating an acute allergic attack that has already started. Your ophthalmologist will advise you on the best way to use it for your specific condition.
How it works
Sodium Cromoglycate (Cromolyn) belongs to a group of medicines called Mast Cell Stabilisers. To understand how it works, let’s first look at what happens during an allergic reaction in your eyes.
When you are exposed to something you are allergic to (like pollen, dust mites, or pet dander), your immune system reacts. In allergic eye conditions, special cells in your eyes called ‘mast cells’ play a key role. When these mast cells encounter an allergen, they release various chemicals, including one called ‘histamine’. Histamine is responsible for many of the uncomfortable symptoms of allergies, such as itching, redness, and watery eyes.
Sodium Cromoglycate works by ‘stabilising’ these mast cells. This means it prevents the mast cells from releasing histamine and other inflammatory chemicals in the first place. By stopping this release, Sodium Cromoglycate effectively prevents the allergic reaction from occurring or significantly reduces its severity. It acts as a shield, protecting your eyes from allergic triggers.
Because it works by preventing the release of these chemicals, it takes some time for the medicine to build up its protective effect. This is why it is used as a preventive therapy and needs to be used regularly, even when you are not experiencing symptoms, especially during allergy season.
How it’s used
Sodium Cromoglycate (Cromolyn) eye drops are typically prescribed for continuous use, especially throughout the allergy season, to prevent allergic reactions in your eyes. Here’s a general guide on how it is usually used:
- Dosing: The usual recommendation is to instill one drop into each affected eye four times a day. Your ophthalmologist will provide specific instructions tailored to your condition and the severity of your allergies.
- Consistency is Key: For this medicine to be effective, it must be used regularly as prescribed by your doctor. It is not a medicine that provides immediate relief for an ongoing allergic attack. Instead, it works over time to build up protection against future allergic reactions.
- Start Early: If you know when your allergy season typically begins, your doctor might advise you to start using these drops a couple of weeks before that time to ensure the medicine has enough time to become fully effective.
- Duration of Use: You will likely need to use these drops continuously throughout the period when you are exposed to allergens or as long as your doctor advises. Do not stop using the drops without consulting your ophthalmologist, even if your symptoms improve.
Always follow your ophthalmologist’s instructions precisely. If you miss a dose, take it as soon as you remember, unless it is almost time for your next dose. Do not double the dose to make up for a missed one.
Always follow your ophthalmologist’s exact instructions.
Brands available in India
- Cromal
- Cromal Forte
Brand availability and pricing vary; confirm with your pharmacist.
Good to know
Prescription eye medicine — use only as directed by a qualified ophthalmologist. This page is for general education and is not a substitute for professional medical advice, diagnosis or a prescription. Do not self-medicate or reuse an old prescription.
Precautions & side effects
While Sodium Cromoglycate (Cromolyn) is generally considered very safe, especially for long-term use in children, there are a few important points to keep in mind:
- Delayed Benefit: A crucial precaution with Sodium Cromoglycate is that it takes time to show its full benefit. Patients often stop using it too early, thinking it is not working, because they don’t see immediate relief. It can take up to two weeks of regular, continuous use for the medicine to build up its protective effect and for you to notice a significant improvement in your symptoms. Be patient and consistent with your dosage as prescribed by your ophthalmologist.
- Prescription Medicine: Sodium Cromoglycate eye drops are a prescription eye medicine. This means you should use them only as directed by a qualified ophthalmologist. Do not self-medicate or reuse an old prescription without consulting your doctor.
- Not for Acute Attacks: Remember, this medicine is for prevention, not for treating an acute or sudden allergic attack that has already started. If you experience a sudden flare-up, consult your doctor for appropriate treatment.
- Contact Lenses: If you wear contact lenses, it is generally advisable to remove them before instilling eye drops and wait at least 15 minutes before reinserting them. Always follow your ophthalmologist’s specific advice regarding contact lens use with eye drops.
- Storage: Store the eye drops as instructed on the packaging, usually in a cool, dry place, away from direct sunlight and out of reach of children.
- Hygiene: Always wash your hands thoroughly before and after using eye drops. Avoid touching the tip of the dropper to your eye or any other surface to prevent contamination.
If you experience any unusual or severe side effects, or if your condition worsens, contact your ophthalmologist immediately.
Understanding Allergic Eye Conditions
Allergic eye conditions, like Vernal Keratoconjunctivitis (VKC) and chronic allergic conjunctivitis, occur when your eyes react to harmless substances in the environment called allergens. Common allergens include pollen from trees, grasses, and weeds, dust mites, pet dander, and certain moulds. When your eyes come into contact with these allergens, your immune system overreacts, leading to symptoms such as intense itching, redness, watery eyes, a burning sensation, and sometimes swelling of the eyelids. In more severe conditions like VKC, there can be significant discomfort, sensitivity to light, and a feeling of something in the eye. These conditions can be seasonal, flaring up during specific times of the year (like spring or monsoon), or perennial, meaning they occur year-round. While not usually sight-threatening, they can significantly impact your quality of life, making daily activities uncomfortable. Managing allergic eye conditions often involves avoiding known allergens, using prescribed eye drops, and sometimes other treatments as advised by your ophthalmologist.
Correct Way to Use Eye Drops
Using eye drops correctly is crucial for their effectiveness and to prevent contamination. Here’s a step-by-step guide:
- Wash Your Hands: Always start by washing your hands thoroughly with soap and water. This prevents germs from entering your eyes.
- Prepare the Bottle: If the bottle has a cap, twist it off. Make sure the dropper tip does not touch any surface, including your fingers.
- Tilt Your Head: Gently tilt your head backward.
- Create a Pouch: With one hand, gently pull down your lower eyelid to create a small pouch.
- Instill the Drop: Hold the eye drop bottle upside down with the other hand, positioning the tip directly over your eye. Look upwards and gently squeeze the bottle to release one drop into the pouch you created. Be careful not to let the tip touch your eye or eyelashes.
- Close Your Eye: Gently close your eye for a minute or two. Avoid blinking excessively or squeezing your eyes shut, as this can push the medicine out.
- Apply Pressure (Optional but Recommended): You can gently press your finger against the inner corner of your eye (near your nose) for about a minute. This helps prevent the medicine from draining into your tear duct and throat, keeping more of it on the eye surface where it’s needed.
- Wipe Excess: Gently blot any excess liquid around your eye with a clean tissue.
- Replace Cap: Put the cap back on the bottle tightly.
- Wash Hands Again: Wash your hands once more to remove any residue.
If you need to use more than one type of eye drop, wait at least 5-10 minutes between different medications to allow each drop to be absorbed properly.
General Eye Care, Hygiene, and When to Seek Help
Maintaining good eye hygiene and following general care practices can significantly help manage allergic eye conditions. Always store your eye drops as directed on the packaging, typically in a cool, dry place, away from direct sunlight and out of reach of children. Never use eye drops beyond their expiry date or more than four weeks after opening the bottle (unless otherwise specified by your doctor or the manufacturer), as they can become contaminated. Avoid sharing eye drops with anyone, even family members, to prevent the spread of infection. If you wear contact lenses, always remove them before instilling eye drops unless specifically advised otherwise by your ophthalmologist, and wait at least 15 minutes before reinserting them. Try to avoid rubbing your eyes, as this can worsen irritation and inflammation. If you know your allergens, try to minimise exposure to them – for example, by keeping windows closed during high pollen counts, using air purifiers, or washing bedding frequently. It is important to see your ophthalmologist regularly for follow-up appointments as advised. You should also seek immediate medical attention if you experience sudden severe eye pain, a significant decrease in vision, persistent redness or discharge, or if your symptoms worsen despite using your prescribed medication. These could be signs of a more serious condition requiring prompt treatment.
Frequently asked questions
What is Sodium Cromoglycate (Cromolyn) used for?
Sodium Cromoglycate (Cromolyn) eye drops are an anti-allergy medicine used to prevent allergic eye conditions such as Vernal Keratoconjunctivitis (VKC) and chronic allergic conjunctivitis. It is used as a preventive therapy rather than for treating an ongoing allergic attack.
How does Sodium Cromoglycate (Cromolyn) work?
Sodium Cromoglycate (Cromolyn) is a mast cell stabiliser. It works by preventing mast cells in your eyes from releasing histamine and other chemicals that cause allergic reactions. By stopping this release, it prevents the allergic symptoms like itching, redness, and watering from occurring.
What are the common Indian brands for Sodium Cromoglycate (Cromolyn) eye drops?
In India, common brands for Sodium Cromoglycate (Cromolyn) eye drops include Cromal and Cromal Forte.
How should I use Sodium Cromoglycate (Cromolyn) eye drops?
Typically, you should instill one drop into each affected eye four times a day. It is crucial to use this medicine continuously and regularly, especially throughout the allergy season, as it works to prevent allergic reactions and takes up to two weeks to show its full benefit. Always follow your ophthalmologist's specific instructions.
Do I need a prescription for Sodium Cromoglycate (Cromolyn) eye drops?
Yes, Sodium Cromoglycate (Cromolyn) eye drops are a prescription medicine. You should only use them as directed by a qualified ophthalmologist. Do not self-medicate or reuse an old prescription.
What are the key precautions I should be aware of when using Sodium Cromoglycate (Cromolyn)?
The most important precaution is that it takes up to two weeks of regular use to show benefit; many patients stop too early thinking it does not work. It is very safe for long-term use, even in children. Remember it is for prevention, not for treating an acute allergic attack. Always use it as prescribed by your ophthalmologist.
References
- Cromolyn Ophthalmic: MedlinePlus Drug Information
- Clinical trial with 2% sodium cromoglycate (Opticrom) in vernal keratoconjunctivitis – PMC
- Vernal Keratoconjunctivitis – American Academy of Ophthalmology
- Learn about eye health – National Eye Institute (NIH)
- Blindness and vision impairment – World Health Organization
Medically reviewed by Dr. C Jagadesh Reddy, Chief Surgeon: Cornea, Cataract and Refractive Surgery — last reviewed 2026-07-28.
This page is for general education only and is not a substitute for professional medical advice, diagnosis or treatment. Never self-medicate or reuse an old prescription. Always consult a qualified ophthalmologist before starting, changing or stopping any eye medicine.