A dilated eye exam allows a detailed view of the retina and optic nerve, helping detect glaucoma, retinal disease, and early vision-threatening changes before symptoms appear. At Dr Shibal Bhartiya’s clinic in Gurgaon, dilated examinations are used for precise diagnosis, risk stratification, and early intervention to protect long-term vision.
A dilated eye exam is the most reliable way to examine the health of the optic nerve, retina, and internal eye structures. It is the only examination that can detect glaucoma or retinal damage before you notice any vision loss yourself. Without dilation, the view inside your eye is severely limited, and early disease can be missed entirely.
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.
Why Dilation Changes Everything
The pupil is the eye’s doorway. In its natural state, it is small, typically 3 to 4 millimetres in bright light. Eye drops used for dilation widen the pupil to 6 to 8 millimetres, opening a clear, unobstructed window to the posterior segment of the eye.
This wider view allows a specialist to assess:
- The optic nerve head: its shape, colour, cup-to-disc ratio, and rim tissue
- The retinal nerve fibre layer, where early glaucoma damage first appears
- The macula, which governs central and detailed vision
- The peripheral retina, where tears, holes, and detachments begin
- Retinal blood vessels, which reflect systemic conditions including diabetes, hypertension, and cardiovascular disease
Without dilation, many of these structures either cannot be seen at all or can only be partially evaluated.
Who Needs a Dilated Eye Exam
A dilated examination is recommended for every adult over 40 years of age. The need is more urgent if you have any of the following:
- A family history of glaucoma (first-degree relatives increase your risk three to nine times)
- Diabetes or pre-diabetes
- High blood pressure or cardiovascular disease
- High myopia (short-sightedness greater than -3.00 dioptres)
- Previous eye trauma or surgery
- Long-term use of steroids: inhaled, topical, or oral
- Symptoms such as loss of peripheral vision, halos around lights, or unexplained headaches
If you are in any of these groups and have not had a dilated examination in the last year, the risk of undetected disease is real.
What Happens During the Exam
The examination begins with instillation of dilating eye drops, typically tropicamide, cyclopentolate, homatropine, phenylephrine or a combination. These take 20 to 30 minutes to reach full effect. During this waiting period, your baseline vision, intraocular pressure (IOP), and anterior segment will already be assessed.
Once the pupils are fully dilated, the specialist examines the fundus using a slit lamp with a high-powered lens, a binocular indirect ophthalmoscope, or both. The optic nerve is examined stereoscopically, meaning in three dimensions, which allows subtle changes in nerve fibre layer or cup architecture to be detected that a photograph alone cannot capture.
The entire examination, including dilation time, takes approximately 45 to 60 minutes.
After the Exam: What to Expect
Dilation causes temporary blurring of near vision and increased light sensitivity. These effects typically resolve within 4 to 6 hours, though in some individuals with lightly pigmented irides it may last slightly longer.
You will be able to see distances reasonably well but reading and close work will be difficult for several hours. Driving is not recommended immediately after dilation. Bring a pair of sunglasses for comfort in bright light. If possible, arrange for someone to accompany you or plan your schedule to allow recovery time before driving.
What the Exam Can and Cannot Tell You
A single dilated examination provides a cross-sectional view: a snapshot of your eye health at that moment. It cannot by itself determine whether glaucoma is progressing. For that, serial examinations comparing optic nerve appearance over time are required, alongside perimetry (visual field testing) and imaging such as OCT (optical coherence tomography).
This is why regularity matters as much as the examination itself. A dilated exam done once and never repeated offers far less protection than annual examinations that allow a trained specialist to identify subtle change over time.
The Difference a Specialist Makes
Not all dilated examinations are equal. The findings depend on the examiner’s training, the equipment available, and whether the posterior segment is being assessed with the specific intent to detect early glaucoma, macular disease, or diabetic retinopathy.
A fellowship-trained glaucoma specialist examining your optic nerve is not performing the same examination as a routine screening. The questions being asked are different: Is this cup configuration within normal variation, or does it carry risk? Is there notching in the inferior or superior rim? Is the pattern of change consistent with early glaucomatous damage?
These distinctions require subspecialty training and experience with high-volume, high-complexity cases.
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. Both, in person, and online.
Frequently Asked Questions
Is a dilated eye exam painful?
No. The dilating drops may cause a brief stinging sensation that resolves within seconds. The examination itself is painless, though the bright light from the ophthalmoscope can feel temporarily uncomfortable.
How often should I have a dilated eye exam?
Once a year if you are over 40, have a family history of glaucoma, diabetes, or high myopia. Every two years may be appropriate for younger adults with no risk factors, though your specialist will guide frequency based on your individual profile.
Can I have a dilated eye exam even if I wear contact lenses?
Yes, but remove your contact lenses before the examination and bring your glasses. Contacts should not be reinserted for at least four to six hours after dilation.
Will I need a dilated exam if I have already had an OCT scan?
OCT provides structural information and is highly valuable, but it does not replace clinical examination. A dilated fundus examination by a specialist adds stereoscopic assessment of the optic nerve and macula; and the ability to detect lesions that imaging alone may miss. However, the final decision, in this case, rests with your doctor.
I have no symptoms. Do I still need a dilated exam?
Yes. This is perhaps the most important point in eye care: several diseases causes no pain and no visible symptoms until significant damage. By the time a patient notices something is wrong, the damage is often advanced and permanent. The entire purpose of a dilated examination is to find disease before symptoms begin. This is especially true for the following diseases:
- Glaucoma
- Retinal diseases like diabetic retinopathy, hypertensive retinopathy, age related macular degeneration
- Cataract
- Refractive errors, especially in children
Can a dilated exam be done during pregnancy?
Dilation drops are generally considered safe during pregnancy, but this should be discussed with your obstetrician and ophthalmologist. Intraocular pressure can fluctuate during pregnancy, and a dilated examination may be particularly important if you have pre-existing glaucoma or risk factors
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 updated 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
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