Wearing both glasses and contacts at the same time is strongly discouraged by eye care professionals. This practice, often called “doubling up,” involves placing two separate, stacked corrective prescriptions in front of the eye simultaneously. Combining the optical power of a contact lens and a spectacle lens almost always results in a significant over-correction of the vision. This over-correction does not improve sight; instead, it introduces uncomfortable and potentially harmful optical and physical complications.
Why Doubling Up Causes Vision Problems and Discomfort
Wearing two corrective lenses creates a combined prescription, inducing blurriness and visual distortion. This excessive power leads to eye strain and can cause headaches and dizziness as the brain struggles to reconcile the distorted image. Furthermore, the optical centers of the spectacle lens and the contact lens are unlikely to align perfectly, which creates an unwanted prismatic effect.
The prismatic effect misdirects light, causing objects to appear displaced and contributing to double vision or spatial disorientation. Beyond the immediate optical problems, wearing two lenses significantly compromises the physical health of the cornea. The cornea receives most of its oxygen directly from the air.
Placing a contact lens, even a modern, highly permeable one, on the cornea already reduces oxygen flow. Stacking a spectacle frame in front of the eye further restricts the ambient air exchange, drastically increasing the risk of corneal oxygen deprivation, known as hypoxia. Hypoxia can lead to corneal edema, resulting in hazy vision and discomfort. Prolonged hypoxia can trigger the growth of abnormal blood vessels into the cornea (neovascularization), which can permanently impair vision.
Safe Solutions for Complex Vision Needs
Patients who consider wearing both corrective lenses often have complex vision issues, such as presbyopia or high astigmatism. Safe and professional alternatives exist to manage these needs without resorting to stacking prescriptions. For age-related near vision loss (presbyopia), the alternatives are multifocal contact lenses or monovision correction.
Multifocal contact lenses contain multiple concentric power zones, allowing the eye to focus light from far, intermediate, and near distances simultaneously. This approach allows both eyes to work together, maintaining binocular vision and depth perception. Another option is monovision, where the dominant eye is corrected for distance vision and the non-dominant eye is corrected for near vision, forcing the brain to adapt and choose the appropriate image.
For high astigmatism, patients should be fitted with specialized toric contact lenses. These lenses stabilize the orientation to correct the irregular corneal curvature. For those with prescriptions too high for standard soft toric lenses, eye care professionals may recommend rigid gas permeable (RGP) lenses. RGP lenses provide a sharper visual result by creating a smooth optical surface over the irregular cornea.
Specialized Scenarios Where Both Are Used
In rare, medically supervised circumstances, or when one lens is non-corrective, wearing both contacts and glasses is permissible. A common exception is wearing non-prescription (“plano”) contact lenses for cosmetic purposes, such as changing eye color. Since these lenses have zero refractive power, they do not interfere with the vision correction provided by spectacles worn over them.
Another exception involves therapeutic or bandage contact lenses. These soft, non-corrective devices protect a damaged or healing corneal surface. These lenses act as a smooth, protective barrier, reducing pain and friction from the eyelid, while the patient wears their regular corrective glasses for clear vision.
In highly specialized cases of corneal disease or post-surgical complication, a patient may be fitted with an RGP lens to correct unique visual distortions. The RGP lens creates an optimal tear-filled space that masks the corneal irregularity, but the patient might still need to wear spectacles over the RGP lens to correct any remaining distance or reading prescription. This combination is always carried out under the direct supervision of an eye care specialist.