Double Vision Can Be a Symptom of Cataracts
Yes, monocular diplopia (double vision in one eye) can be a symptom of cataracts, particularly when the opacity affects specific parts of the lens. 1
Types of Cataracts and Associated Visual Symptoms
- Nuclear cataracts involve central opacification or discoloration of the lens, typically progressing slowly and affecting distance vision more than near vision 2
- Cortical cataracts appear as opaque spokes or oil droplets and commonly cause glare symptoms 2
- Posterior subcapsular cataracts (PSCs) are located just inside the posterior lens capsule and can cause substantial visual impairment with glare and poor vision in bright light 2
- Monocular diplopia (double vision that persists when the unaffected eye is covered) is specifically associated with certain types of cataracts 1, 3
How Cataracts Cause Double Vision
- Cataracts can cause monocular diplopia through irregular refraction of light as it passes through the partially opacified lens 1
- This symptom differs from binocular diplopia (where double vision resolves when either eye is covered), which is typically caused by ocular misalignment or strabismus 3
- Monocular diplopia from cataracts disappears when the affected eye is covered but persists when viewing with only the affected eye 3
Other Common Symptoms of Cataracts
- Decreased visual acuity at distance and/or near that may not improve with refraction 4
- Visual glare, especially in bright lighting conditions or while driving at night 4
- Reduced contrast sensitivity affecting daily activities 4
- Myopic shift (change in refractive error toward nearsightedness) 1
- Changes in color perception 1
Diagnostic Considerations
- Diagnosis of cataract-related monocular diplopia requires slit-lamp examination after pupillary dilation 1
- Glare testing is particularly useful for evaluating cataracts, as it can reveal functional disability greater than Snellen acuity alone suggests 4
- Contrast sensitivity testing may reveal functional vision loss not detected by standard visual acuity testing 4
- It's important to distinguish monocular diplopia (cataract-related) from binocular diplopia (typically caused by ocular misalignment) 3
Management Implications
- When monocular diplopia is caused by cataracts, cataract surgery is the definitive treatment 5
- Surgery is indicated when visual impairment from cataracts affects activities of daily living despite optimal correction 4
- Cataract surgery can resolve the monocular diplopia by replacing the opacified natural lens with a clear intraocular lens 5
- Interestingly, binocular diplopia can sometimes develop after cataract surgery due to various mechanisms, including decompensation of pre-existing strabismus or extraocular muscle issues 6
Clinical Pearls and Caveats
- Always rule out other causes of vision loss before attributing symptoms solely to cataracts 4
- Visual acuity testing alone may underestimate the functional impact of cataracts; glare testing and contrast sensitivity provide additional information 4
- Monocular diplopia that persists after cataract surgery may indicate other ocular issues and warrants further evaluation 6
- Patients with cataracts may experience progressive worsening of symptoms, including diplopia, as the opacity increases 2