1. Cataract
It is a clouding or opaqueness of the crystalline lens which leads gradual painless blurring and eventual loss of vision

3. A cause of blindness and is conventionally treated with surgery
Vision loss occurs because opacification of the lens obstructs light from passing and being focused on the retina
3rd leading cause of preventable blindness

4. Due to etiological factors
Altered oxidative reactions
Decrease in the function of active transport of pump mechanism of lens
Decreased level of amino acids
Reversal of sodium /potassium ratio
Hydration of lens fibers
Decreased synthesis of proteins in lens fibers
Denaturation of lens proteins
Opacification of cortical lens fibers

5. Causes Aging Loss of lens transparency Decreased oxygen uptake
Denaturation of proteins in lens
Accumulation of a yellow brown pigment due to the break down of lens protein

6. Trauma
Blunt trauma causes swelling, thickening and whitening of the lens fibers
Swelling resolves but white color remains Or
Capsule can be damaged and allows water from other parts to enter the lens, obstructing light from reaching the retina

7. Associated ocular conditions
Retinitis pigmentosa – degenerative disorder caused by abnormalities of the photoreceptors
Myopia
Retinal detachment and retinal surgery
Infection

8. Toxic factors Nutritional factors Corticosteroids
Chemical eye burns or poisoning
Cigarette smoking
Reduced levels of antioxidants – antioxidants helps to prevent oxidative changes in proteins and fat
Poor nutrition
Obesity
Nutritional factors

9. Physical factors Perforation of lens with sharp object or foreign body
Electric shock
Ultraviolet radiation
Risk factors – age, ultraviolet light exposure, high dose of radiation exposure, drug effects, trauma

10. Systemic diseases and syndromes
Diabetes mellitus
Down syndrome
Renal disorders
Musculoskeletal disorders

11. Classification Age related cataracts (senile cataract)
Based on the area of lens
Congenital cataract
Nuclear, cortical and posterior subcapsular cataracts
Secondary cataract
Traumatic
Based on the characteristics
Partial or complete
Stationary or progressive
Hard or soft

12. Posterior subcapsular cataract
Nuclear cataract
Central opacity in the lens
It is associated with myopia
Cortical cataract involves the anterior, posterior or equatorial (peripheral) cortex of the lens
People with highest levels of sunlight exposure have twice the risk
Posterior subcapsular cataract occur in front of the posterior capsule.
Typically develop in younger people
Associated with prolonged corticosteroid use, diabetic and ocular trauma
Cortical cataract
Posterior subcapsular cataract

13. Signs and symptoms Painless, blurry vision Reduced visual acuity
Myopic shift – return of ability to read without glasses
Astigmatism -  optical defect in which vision is blurred due to the inability of the optics of the eye to focus a point object into a sharp focused image on the retina
Visible opaqueness

14. Diplopia
Abnormal color perception, glare (due to light scatter caused by lens opacities and significantly worse at night and in bright light when th pupil dilates )
Brunescence – color shift from yellow to brown
Reduced light transmission
Color of pupil will be yellowish, gray or white
Develop in both eyes

15. Diagnostic findings Visual acuity measurements
Snellen visual acuity test
Ophthalmoscopy
Slit lamp microscopic examination
Blood test
Visual field perimetry
A – scan ultrasound

16. Prevention Avoid the risk factors – UV rays, x rays, smoking
Wear sunglasses
Regular intake of antioxidants (vitamins A,C AND E) would protect against risks
Prevent accidents
Treat underlying disorders properly

17. Management Non surgical treatment will not cure cataract
Surgery is performed as outpatient basis usually takes less than 1 hour and discharged in 30 minutes
Topical and intra ocular anesthesia – 1% lidocaine gel is used
Patient can communicate and cooperate during surgery
IV moderate sedation – to minimize anxiety

18. When both eyes have cataracts – one eye is treated first, after several weeks the other cataracts is been managed.
This will help one eye to heal properly and the doctor can check the surgical procedure is effective or not
The doctor can also check the presence of any complications due to surgery.

19. Phacoemulsification Most widely used cataract surgery
Through a very small incision in the surface of the eye
An ultrasound probe is then inserted
This uses ultrasonic vibrations to dissolve (phacoemulsify) the clouded lens
These tiny fragmented pieces are then suctioned out through the same ultrasound probe
Once the cataract is removed, an artificial lens is placed into the thin capsular bag

20. Steps of phacoemulsification
Anesthesia
Exposure of the eyeball using a lid speculum
Entry into the eye through a minimal incision
Viscoelastic injection to stabilize the anterior chamber
Capsulorhexis -Ultrasonic destruction or emulsification and aspiration of the fragments
Implantation of the intra ocular lens
Viscoelastic removal
Wound sealing

22. Extra capsular cataract extraction ECCE
Only uses in very advanced cataracts where the lens is too dense to dissolve into fragments
This technique requires a larger incision so that the cataract can be removed in one piece without being fragmented inside the eye
The posterior capsule is left intact.
An artificial lens is place in the same capsular bag
An eye patch after the surgery is needed.

23. Intracapsular cataract extraction ICCE
This surgical technique requires an even larger wound than extracapsular surgery
In this the entire lens and the surrounding capsule is removed
Intra ocular lens is placed in front of the iris.

24. Lens replacement
After removal of the crystalline lens, the patient is referred to as aphakic (without lens)
Three lens replacement options – aphakic eye glasses, contact lens, and IOL implants
IOL -It is permanently placed, no maintenance or handling and neither felt by the patient nor noticed by others
Made of silicone or acrylic material

25. Monofocal lens – commonly implanted lenses
They have equal power in all regions of the lens and can provide high quality distance vision
It have sharpest focus at only one distance
Usually a pair of spectacles is need for better quality

26. Toric lens – it have more power in one specific region in the lens
Multifocal lens – latest advancements
It have variety of regions with different power that allows individuals to see at a variety of distances, including distance and near
BUT They can cause more glare than monofocal or toric lenses

28. Preoperative care
Eye examination by surgeon to confirm the presence of cataract and to determine the patient is suitable candidate for surgery
Eyes should have normal pressure. If increased pressure is there it should be controlled with medication before surgery
In some cases a combined cataract – glaucoma procedure (phaco trabeculectomy) can be planned

29. Pupil should be adequately dilated
Retinal detachment should be ruled
NPO – 6- 8 HOURS BEFORE in selected cases
Pre operative antibiotic eye drops
NSAIDS eye drops
Mydriatics – phenylephrine HCL acid
Every 10 min for four doses atleast 1 hour before surgery
cycloplegics (paralyses the ciliary muscles thus losing the accommodation of lens) - tropicamide, atropine, cyclopentolate HCL

30. Post operative care Discharged within few hours
Eye patch should be done – the dressing is removed a day after surgery
Position the patient on back or up operated side to prevent pressure in operated eye
Eye protective shields should be provided for 2-3 weeks for avoiding accidental injury
Proper follow up – 4-5 visit in a period of 5 to 6 weeks
Tell the patient to avoid situation that IOP can increases (sneezing, coughing, vomiting, straining, or sudden bending)

31. Instruct the patient Avoid touching the operative eye
Take care to prevent soap or water from entering the operative eye during face or hair washing
Avoid heavy lifting
Exercise in moderation
Wash hands before instilling eye medications
Wear sunglasses to prevent bright lights
Wait 2 -3 min between administration of different eye medications (antibiotics and corticosteroids)
Administer eye ointments last
Avoid smoking, driving

32. Complications of cataract surgery
Immediate preoperative complications
Retrobulbar hemorrhage – can result due to anesthesia injection
Effects – increased IOP, lid tightness, and subconjunctival hemorrhage
Management
Canthotomy – slitting of canthus to reduce the IOP
Puncture of anterior chamber

33. Intraoperative complications
Rupture of posterior capsule and Suprachoroidal hemorrhage
Management is vitrectomy

34. Post operative complications
Early
Acute bacterial endophthalmitis – antibiotic therapy
Toxic anterior segment syndrome (TASS) – non infectious inflammation caused by toxic agent used to sterilize surgical instruments
Late
Suture related problems
Malposition of IOL
Opacification of posterior capsule