Title: Nuclear sclerosis

{{Short description|Age-related disease of the eye}}
[[Image:Nuclear sclerosis 1.JPG|thumb|Nuclear sclerosis]]

'''Nuclear sclerosis''' is an age-related change in the [[density]] of the [[lens (anatomy)|crystalline lens]] nucleus that occurs in all older animals.&lt;ref&gt;{{cite web|url=http://www.vetmed.iastate.edu/services/vth/clinical/ophth/faq-vet.asp#sclerosis|title=Cataract Surgery – FAQs: What is nuclear sclerosis?|archive-url=https://web.archive.org/web/20070313183844/http://www.vetmed.iastate.edu/services/vth/clinical/ophth/faq-vet.asp |archive-date=2007-03-13|publisher=[[Iowa State University College of Veterinary Medicine]], Veterinary Teaching Hospital, Ophthalmology Department|access-date=2006-11-18}}&lt;/ref&gt; It is caused by compression of older lens fibers in the nucleus by new fiber formation.  The denser construction of the nucleus causes it to [[scattering|scatter]] light. Although nuclear sclerosis may describe a type of early [[cataract]] in [[medicine|human medicine]],&lt;ref name=&quot;Cassin&quot;&gt;Cassin, B. and Solomon, S. ''Dictionary of Eye Terminology''. Gainesville, Florida: Triad Publishing Company, 1990.&lt;/ref&gt; in [[veterinary medicine]] the term is also known as '''lenticular sclerosis''' and describes a bluish-grey haziness at the nucleus that usually does ''not'' affect vision, except for unusually dense cases. Immature senile cataract has to be differentiated with nuclear sclerosis while making its diagnosis.&lt;ref&gt;{{cite journal | last = Sapienza | first = John S. | title = Cataracts | journal = Proceedings of the 27th World Congress of the World Small Animal Veterinary Association | year = 2002 | url = http://www.vin.com/proceedings/Proceedings.plx?CID=WSAVA2002&amp;PID=2648 | accessdate = 2007-03-13 }}&lt;/ref&gt;

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==Veterinary medicine==
In veterinary practice, nuclear sclerosis is a consistent finding in [[dog]]s greater than six years old.&lt;ref name=&quot;Gelatt_1999&quot;&gt;{{Cite book |last=Gelatt |first=Kirk N. |title=Veterinary ophthalmology |date=1999 |publisher=Lippincott Williams &amp; Wilkins |isbn=978-0-683-30076-5 |edition=3rd |location=Philadelphia}}&lt;/ref&gt; Nuclear sclerosis appears as a bilateral bluish-grey haziness at the nucleus, or center of the lens, caused by an increase in the [[refractive index]] of that part of the lens due to its increased density. It is often confused with other types of cataract. The condition is differentiated from other types of cataract by its clinical appearance, by shining a penlight into the eye (retroillumination).  With nuclear sclerosis, a reflection from the [[tapetum lucidum|tapetum]] will be seen, while a localized cataract may block reflection and appear as a shadow in the lens.&lt;ref&gt;{{cite web | last = Petersen-Jones | first = Simon M. | title = Conditions of the Lens | work = Proceedings of the 28th World Congress of the World Small Animal Veterinary Association | year = 2003 | url = http://www.vin.com/proceedings/Proceedings.plx?CID=WSAVA2003&amp;PID=6686&amp;O=Generic | accessdate = 2007-03-13 }}&lt;/ref&gt;
There is no treatment for this condition currently.

==References==
{{reflist}}

==External links==
* [http://www.opt.indiana.edu/riley/HomePage/Age_related_Cats/2Text_age_related_cats.html Images]

[[Category:Dog diseases]]
[[Category:Eye diseases]]
[[Category:Medical signs]]