“Any opacity in the lens or its capsule whether developmental or
acquired is called a cataract.
• Usually developmental opacities are stationary and
• Acquired opacities progress till entire lens is involved
• Damage to the lens by trauma, toxins, hydration or UV
rays affect lens transparency.
4. • The patient may have a cataract in one or both eyes.
• If present in both eyes, one cataract may affect the patient's
vision more than the other.
• Cataracts are the third leading cause of preventable blindness
and the most common cause of self-declared visual disability in
the United States.
• TheWHO/NPCB (National Programme for Control of Blindness) survey has
shown that there is a backlog of over 22 million blind eyes (12 million blind
people) in India, and 80.1% of these are blind due to cataract.
• The annual incidence of cataract blindness is about 3.8 million.
• Cataract is due to degeneration and opacification of formed lens fibers,
formation of aberrant lens fibers or deposition of other materials in their space.
This is due to
• Denaturation of lens proteins
• Decreased vision: most obvious and important because of reduced
transparency of lens
• Decreased contrast sensitivity
• Refractive error like myopia due to change in RI of
• Nucleus and hence frequent change of glasses
• Monocular diplopia and colored halos due to irregular refraction by different
parts of lens
• Glare due to scattered light rays
• Change in color values ie red is accentuated
15. Diagnostic studies
• History and physical examination
• Visual acuity measurement
• Ophthalmoscopy (direct and indirect)
• Slit lamp microscopy
• Glare testing, potential acuity testing in selected patients
• Keratometry and A-scan ultrasound (if surgery is planned)
• Other tests (e.g., visual field perimetry) may be indicated to differentiate
visual loss of cataract from visual loss of other causes
The aim of treatment is:
1. Improve vision
2. Increase mobility and independence
3. Relief from the fear of going blind
17. Acute Care: Surgical Therapy
• Intracapsular cataract extraction
• Involves extraction of the entire lens, including the
posterior capsule and zonules
• Weak and degenerated zonules are a pre-requisite for this
• This is the surgery of choice if there is markedly
subluxated or dislocated lens
• This technique of surgery has largely been replaced by
18. Extracapsular cataract extraction
• An 5 mm to 6 mm incision is made in the eye where the clear front
covering of the eye (cornea) meets the white of the eye (sclera).
• Another small incision is made into the front portion of the lens capsule.
The lens is removed, along with any remaining lens material.
• An IOL (Intra Ocular lens) may then be placed inside the lens capsule.
And the incision is closed.
• Two small incisions are made in the eye where the clear front covering(cornea)
meets the white of the eye (sclera).
• A circular opening is created on the lens surface (capsule)
• A small surgical instrument (phaco probe) is inserted into the eye.
• Sound waves (ultrasound) are used to break the cataract into small pieces.
• Sometimes a laser is used too.The cataract and lens pieces are removed from
the eye using suction.
• An intraocular lens implant (IOL) may then be placed inside the lens capsule.
• Usually, the incisions seal themselves without stitches.
21. Pre Operative care
• The patient's preoperative preparation should include an appropriate history
and physical examination.
• Because almost all patients have local anesthesia, many physicians and surgical
facilities do not require an extensive preoperative physical assessment.
• However, most cataract patients are older adults and may have several
medical problems that should be evaluated and controlled before surgery.
• The surgeon may order preoperative antibiotic eyedrops.
• The patient should not have food or fluids for approximately 6 to 8 hours
• Almost all patients with cataracts are admitted to a surgical facility on an
• The patient is normally admitted several hours before surgery to allow
adequate time for necessary preoperative procedures.
22. • The instill of dilating drops and a nonsteroidal antiinflammatory eyedrop are
used to reduce inflammation and to help maintain pupil dilation.
• One type of drug used for dilation is a mydriatic, an α-adrenergic agonist that
produces pupillary dilation by contraction of the iris dilator muscle.
• Another type of drug is a cycloplegic, an anticholinergic agent that produces
paralysis of accommodation (cycloplegia) by blocking the effect of acetylcholine
on the ciliary body muscles.
• Cycloplegics produce pupillary dilation (mydriasis) by blocking the effect of
acetylcholine on the iris sphincter muscle.
• The patient often receives preoperative antianxiety medication before the local
23. Postoperative Phase.
• Unless complications occur, the patient is usually ready to go home as soon as
the effects of sedative agents have worn off.
• Postoperative medications usually include antibiotic drops to prevent infection
and corticosteroid drops to decrease the postoperative inflammatory response.
• There is some evidence that postoperative activity restrictions and nighttime
eye shielding are unnecessary.
• However, many ophthalmologists still prefer that the patient avoid activities
that increase the IOP, such as bending or stooping, coughing, or lifting.
• Ophthalmologists may also recommend using an eye shield over the operative
eye at night for protection.
24. • The ophthalmologist will usually see the patient four to five times at increasing
intervals throughout the 6 to 8 weeks following surgery.
• During each postoperative examination the surgeon will measure the patient's
visual acuity, check anterior chamber depth, assess corneal clarity, and
• A flat anterior chamber may cause adhesions of the iris and cornea.
• The cornea may become hazy or cloudy from intraoperative trauma to the
25. • Even on the operative day the patient's uncorrected visual acuity in the
operative eye may be good.
• However, it is not unusual or indicative of any problem if the patient's visual
acuity is reduced immediately after surgery.
• The postoperative eyedrops will be gradually reduced in frequency and
finally discontinued when the eye has healed.
• When the eye is fully recovered, the patient will receive a final prescription
• Although the majority of the postoperative refractive error is corrected with
the intraocular lens, the patient will still need corrective eyewear for near
vision and for any residual refractive error.
• This is prescribed when healing is complete, approximately 6 to 8 weeks