Cataract: Disease process and pathology, 2nd year, UODA

1. Cataract
Presented by
Mirza Nipa Monalisa
Asst. Professor, UODA

2. Definition:
– A cataract is a dense, cloudy area that forms in the lens of the eye. A cataract
begins when proteins in the eye form clumps that prevent the lens from
sending clear images to the retina. The retina works by converting the light that
comes through the lens into signals. It sends the signals to the optic nerve,
which carries them to the brain.
– It develops slowly and eventually interferes with your vision. You might end up
with cataracts in both eyes, but they usually don’t form at the same time.
Cataracts are common in older people. Over half of people in the United States
have cataracts or have undergone cataract surgery by the time they’re 80 years
old, according to the National Eye Institute.

3. Symptoms of Cataracts
– Common symptoms of cataracts include:
– blurry vision
– trouble seeing at night
– seeing colors as faded
– increased sensitivity to glare
– halos surrounding lights
– double vision in the affected eye
– a need for frequent changes in prescription glasses

4. What Causes Cataracts?
– There are several underlying causes of cataracts. These include:
– an overproduction of oxidants, which are oxygen molecules that have been
chemically altered due to normal daily life
– smoking
– ultraviolet radiation
– the long-term use of steroids and other medications
– certain diseases, such as diabetes
– trauma
– radiation therapy

5. Types of Cataracts
– Age-related (or senile) cataracts: The formation of cataracts becomes fairly common in individuals 80
years of age and older, but can cause noticeable symptoms in individuals after the age of 60 as well.
Some people may develop cataracts as early as middle age (40 or 50 years of age) too. The majority of
age-related cataracts develop as a result of protein clumping (usually around the nucleus portion of the
lens), which tends to slowly increase in size. Over time the cataract become larger and gradually results
in vision becoming duller and blurrier. The lens of the eye also slowly changes colour and typically
becomes yellowish / brownish. This tinted colour change gradually produces the same hue change to
vision as well. More advanced hue tint changes can make it increasingly difficult for a person to perform
normal routine activities due to decreased visual ability. Tint changes also make it more difficult for
individuals to identify purple and blue colours, often interpreting the colour as much darker than it
actually is (i.e. black

6. Types of Cataracts
– Nuclear cataracts: These cataracts develop in the middle portion of the lens,
causing a yellowish / brownish discolouration in the centre (a nucleus). This
type can also result in near-sightedness. The denser the discolouration, the
blurrier vision becomes over time, along with increased difficulty in
distinguishing between colours.
– Cortical cataracts: These form around the edges of the nucleus (lens), creating a
wedge shape or the development of streaks along the outer lens cortex. The
cataract begins as a whitish tint and slowly progresses with streaks edging
closer to the centre of the nucleus. This then progressively interferes with the
ability of light to pass through the lens centr

7. Types of Cataracts
– Posterior subcapsular cataracts: This type of cataract affects the back of the
lens and generally forms quicker than a nuclear or cortical cataract type. The
cataract initially forms as a small opaque area at or near the back of lens of the
eye, but normally directly in the path of where light would normally enter. This
type disrupts vision relating to reading ability, causes halos and glare (especially
around lit up areas at night) and may reduce visual ability in bright light.
– Congenital cataracts: A baby is born with cataracts (in one or both eyes) due to
infectious causes, injury or impaired development in the uterus during
pregnancy (intrauterine infection or trauma). A baby may also be born with a
susceptibility for developing cataracts within his or her first year of life.

8. Types of Cataracts
– Secondary cataracts: These types of cataracts normally occur as a result of
other existing problems such as medical conditions, exposure to toxic
substances, radiation or UV light, as well as long-term use of diuretics or
corticosteroid medications used to treat various health concerns.
– Traumatic cataracts: This type refers to cataracts which develop as a result of
penetrative or blunt injury to the eye. The development of cataracts, however,
may not occur directly following injury and can take a few years to develop.
– Radiation cataracts: Radiation based treatments, such as those used for cancer,
may sometimes cause the development of this type of cataracts.

10. Risk Factors of Cataracts
– Risk factors associated with cataracts include:
– older age
– heavy alcohol use
– smoking
– obesity
– high blood pressure
– previous eye injuries
– a family history of cataracts
– too much sun exposure
– diabetes
– exposure to radiation from X-rays and cancer treatments

11. Diagnosing Cataracts
Acuity Test
– The visual acuity test is the standard eye test we all know. Patients are asked to read letters from a chart with large and small characters – the number
of letters a patient can identify shows how accurate vision is.
– To perform a complete visual acuity test opthalmologists, or an optician, check eyes together and separately to give an indication of how good the vision
is in each eye and the standard of the patients overall vision
Pupil Dilation Test
– A pupil dilation test allows the opticion or opthalmologist to examine the insde of the eye. Eye drops are used to make the pupils dilate.
– As the drops take effect the patient is asked to look straight ahead while the ophthalmologist shines a bright light into the eye and uses a special lens to
exmaine the back part of the eye and note the way light hits the retina.
– This test is especially accurate at diagnosing cataracts as the cataract distorts the way light enters the eye and causes light to shatter in the eye
before reaching the retina
Tonometry
– Tonometry is the third part of a complete eye examination and this measures the pressure of the fluid in the eye. Eyes may be numbed with eye drops
before the ophthalmologist gently places pressure on the eye surface. Sometimes a short puff of air is blown into the eye.
– A tonometry test is not painful but is a very important part of a full eye examination. Tonometry tests can detect other eye problems such as glaucoma,
as well as cataracts.
– A complete eye examination to diagnose cataracts takes 45 mins – one hour to complete.
– Keep in mind that the eye drops will blur vision temporarily so it is advisable patients have somebody to accompany them.

12. Treatment of Cataracts
– If you’re unable or uninterested in surgery, your doctor may be able to help you manage your
symptoms. They may suggest stronger eyeglasses, magnifying lenses, or sunglasses with an anti-
glare coating.
– Surgery
– Surgery is recommended when cataracts prevent you from going about your daily activities, such as
reading or driving. It’s also performed when cataracts interfere with the treatment of other eye
problems.
– One surgical method, known as phacoemulsification, involves the use of ultrasound waves to break
the lens apart and remove the pieces.
– Extracapsular surgery involves removing the cloudy part of the lens through a long incision in the
cornea. After surgery, an artificial intraocular lens is placed where the natural lens was.
– Surgery to remove a cataract is generally very safe and has a high success rate. Most people can go
home the same day as their surgery.

13. Conventional phacoemulsification in a case
of white cataract. Notes:
(A) Initial small capsulorhexis in a case of
intumescent white cataract undergoing
conventional phacoemulsification.
(B) Aspiration of liquefied cortex to
decrease intralenticular pressure.
(C) secondary enlargement of
capsulorhexis to desired size.
anterior capsular tear in a case of FlaCs. Notes:
(A)Polishing of anterior capsule in a case of FlaCs
with Type ii capsulotomy.
(B)anterior capsular tear and extension in 1 clock
hour during polishing of anterior capsule
(arrow: site of anterior capsular tear with extension).
Abbreviation: FlaCs, femtosecond laser-assisted
cataract surgery.

14. Outlook of a Cataract
– Cataracts can interfere with daily activities and lead to blindness when left
untreated. Although some stop growing, they don’t get smaller on their own.
The surgical removal of cataracts is a very common procedure and is highly
effective roughly 90 percent of the time, according to the National Eye Institute.

15. Prevention of Cataracts
– To reduce your risk of developing cataracts:
– protect your eyes from UVB rays by wearing sunglasses outside
– have regular eye exams
– stop smoking
– eat fruits and vegetables that contain antioxidants
– maintain a healthy weight
– keep diabetes and other medical conditions in check