Visual deterioration occurs with increasing degrees of severity, and left untreated may present as complete blindness. The diagnosis is made clinically.
Common causes include:
- old age (most common)
- congenital (see: congenital cataract)
- diabetes mellitus (osmotic)
- e.g. 'radiation-induced cataract' in the interventional radiologist 1
Ocular ultrasound is performed when there is suspicion of posterior globe pathology but fundoscopic assessment of the back of the eye is obscured by the opaque lens. The lens will demonstrate increased wall thickness and hyperechogenicity 4.
Especially useful in acute cataract formation with increased fluid within the lens as in traumatic and osmotic cataract (hyperglycemia) as well as unsuspected lens injury. The affected lens is hypodense compared to the contralateral lens with a mean density difference of about 30 HU 3. If osmotically swollen, the lens will be larger than usual. CT is not the investigation of choice for the lens as radiation may worsen lens opacification.
Treatment and prognosis
Treatment is surgical extraction of the lens nucleus from its capsule and replacement with an intraocular lens implant into the native lens capsule (the presence of an implant instead of the native lens is called pseudophakia).
- 1. Ainsbury EA, Bouffler SD, Dörr W et-al. Radiation cataractogenesis: a review of recent studies. Radiat. Res. 2009;172 (1): 1-9. doi:10.1667/RR1688.1 - Pubmed citation
- 2. Congdon N, Vingerling JR, Klein BE et-al. Prevalence of cataract and pseudophakia/aphakia among adults in the United States. Arch. Ophthalmol. 01;122 (4): 487-94. doi:10.1001/archopht.122.4.487 - Pubmed citation
- 3. Boorstein JM, Titelbaum DS, Patel Y, Wong KT, Grossman RI. CT diagnosis of unsuspected traumatic cataracts in patients with complicated eye injuries: significance of attenuation value of the lens. AJR. American journal of roentgenology. 164 (1): 181-4. doi:10.2214/ajr.164.1.7998535 - Pubmed
- 4. Rosa M. Lorente-Ramos, Javier Azpeitia Armán, Araceli Muñoz-Hernández, José Manuel García Gómez, Susana Bilbao de la Torre. US of the Eye Made Easy: A Comprehensive How-to Review with Ophthalmoscopic Correlation. (2012) RadioGraphics. 32 (5): E175-200. doi:10.1148/rg.325115105 - Pubmed