An eye examination assesses both the clarity of your vision and the overall health of your ocular structures. Proper preparation is essential for ensuring the accuracy of the results, especially the measurements used to determine a corrective lens prescription. Failing to prepare can lead to inaccurate findings or mask a health issue. Understanding what actions and substances to avoid immediately before your appointment helps your eye care professional obtain the clearest picture of your natural eye state.
Actions That Interfere With Refraction
The most impactful action to avoid is wearing contact lenses right before your comprehensive exam. Contacts, whether soft or hard, temporarily reshape the cornea, the clear, dome-shaped front surface of the eye responsible for most focusing power. When the cornea’s natural curvature is altered, the refraction test—the process of determining your glasses prescription—will yield incorrect measurements. For soft lens wearers, doctors recommend removal at least two hours prior; RGP or hard lenses require a much longer period, often 24 to 48 hours. Always bring your contact lens case and your current glasses or prescription with you.
Physical Items To Remove Beforehand
Applying heavy eye makeup can create a barrier that complicates several parts of the eye examination. Products like mascara and eyeliner can shed tiny particles, which may contaminate diagnostic equipment, such as the tonometer used to check eye pressure. Makeup residue can also obscure the intricate structures around the eye, hindering the doctor’s ability to perform a detailed inspection using a slit lamp microscope. Facial creams, sunscreens, or heavy moisturizers applied near the orbital area can also migrate into the eye. If your pupils need to be dilated, the moisture from these products can cause the drops to run, leading to smearing, burning, and irritation.
Activities That Induce Temporary Eye Strain
Avoid prolonged, intensive close-up visual tasks, like reading a novel or marathon computer gaming, in the immediate hours leading up to your exam. These activities force the ciliary muscle, the internal focusing muscle, to remain in a contracted state for an extended period. This temporary over-contraction is known as an accommodative spasm and can simulate a higher degree of nearsightedness than you actually have. When the refraction test is performed on an eye with this muscular fatigue, the resulting prescription may be artificially strong. This phenomenon, sometimes called pseudo-myopia, can be prevented by resting your eyes in the hour or two before your visit.
Substances That Affect Pupil Response
Consuming large amounts of caffeine or alcohol before an eye exam can interfere with a true assessment of your neurological and vascular health. Caffeine is a stimulant that can temporarily cause the pupils to widen and increase the eye’s focusing power, skewing measurements of pupil size and accommodation. Alcohol acts as a diuretic, promoting dehydration that can lead to eye dryness and temporary blood vessel swelling, causing redness. Unauthorized use of over-the-counter redness-relieving eye drops is also highly discouraged. These drops contain vasoconstrictors that shrink visible blood vessels, artificially masking underlying issues like infection, inflammation, or allergy. Always inform your doctor of all medications, including any sleep aids taken the night before, as some can cause temporary vision changes or dryness.