Double vision, also known as diplopia, can be defined as the concurrent perception of two images of a single object. This condition can have many underlying causes; however, a thorough physical examination and a detailed history of the patient can help the physician to make an accurate diagnosis. Importantly, there are two types of diplopia: monocular and binocular. In fact, it is one of the first aspects of diplopia that a physician must determine during an assessment. Hence, if you are experiencing double vision, the physician will likely ask you to cover one eye: if the symptom persists it is probably monocular diplopia. However, if the double vision disappears after this test, then it is likely binocular. In both cases, a comprehensive clinical investigation will take place to differentiate between multiple possible causes.
Monocular diplopia is generally caused by problems within the eye itself. For instance, refractive errors (astigmatism), dry eye, corneal problems, changes in the lens (i.e. cataracts), retinal disease, and certain medications can cause monocular diplopia. Conversely, binocular diplopia is commonly caused by conditions that affect the muscles around the eyeballs that control the direction of our gaze (i.e. cranial nerve palsies). Additionally, injuries to the central nervous system (i.e. tumors, vascular events), trauma to the orbit, thyroid eye disease, neurological diseases (i.e. Myasthenia Gravis), and drugs are among the countless factors that can lead to binocular diplopia.
Undoubtedly, the duration and treatment of double vision will depend on its cause. It is of great importance to contact your healthcare provider if you experience drastic changes in your vision, including diplopia.
Cataracts are a condition that affects the lens of the eye. This structure is also known as the crystalline and it is the one in charge of refracting light to the retina. Additionally, it adjusts its shape constantly (accommodation) so we can focus sharp images in the back of our eye. The crystalline is normally clear; however, its clouding or opacification can be caused by cataracts. Risk factors for cataracts include aging, previous eye-trauma, and long-standing diabetes.
In cataracts, visual changes like diplopia, blurry vision, sensitivity to light, and impaired night vision occur gradually. Moreover, people with cataracts can experience monocular diplopia or double vision. In this case, the light that enters the eye can become scattered by the defect in the lens causing multiple images in their vision. Fortunately, cataracts can be treated surgically. The affected lens can be removed and replaced by an artificial lens in a swift procedure that will greatly improve vision for most patients.