This document provides information about cataracts and cataract surgery. It defines a cataract as any opacity of the crystalline lens. It describes the anatomy of the normal lens and how it changes with age. It discusses the various types of cataracts and their causes. Symptoms include glare, reduced vision, and changes in refractive error. Examination involves evaluating the red reflex and examining the lens under a slit lamp. Treatment is typically phacoemulsification surgery, which uses ultrasound to break up and remove the cloudy lens. The cloudy lens is replaced with an intraocular lens. Post-operative care involves eye drops and follow up visits to monitor healing and vision.

1. CATARACT AND
REFRACTIVE SURGERY
Ms. A. Bobart Hone
2009

2. CATARACT
• The term CATARACT denotes
any opacity of the crystalline lens
whether it affects the visual acuity
or not

3. Anatomy
• Newborn - 3.5mm antero-posteriorly and 5mm equatorially
• Unique to the lens is continued growth throughout life
• Adult - 5mm antero-posteriorly and 9 - 10mm equatorially-i.e.. top to bottom
• With age the lens becomes larger, more compact and less elastic
• The lens is a biconvex optical structure behind iris and in front of vitreous in
posterior chamber of the eye
• It is avascular and not innervated
• Encircled by ciliary processes from which the zonules (suspensory ligament)
radiate to the lens surface
• Zonules hold the lens in place and mediate the accommodative movements of
the ciliary muscle, therefore altering the lens shape.
• Outmost layer is an acellular capsule (basement membrane) that surrounds the
lens
• Anteriorly and just under the anterior capsule is the lens epithelium
• Inner body of lens composed of tightly packed highly organised lens fibres
• Innermost layer called the nucleus
• Outer layers cortex

4. Red reflex with pen torch

5. Nuclear cataract
( N.B. Pseudoexfoliation)

6. Brunescent nuclear sclerosis

7. Cortical cataract and Posterior
subcapsular cataract

8. Cortical Cataract

9. Cortical cataract- multiple white
spokes

10. Aetiology of Cataract
• Age related
• Physical - Trauma (often unilateral)
• Electric shock (anterior subcapsular)
• Radiation
• Systemic - Diabetes
• Dermatological - Atopic dermatitis
• CNS disorders - Neurofibromatosis II which is one
of the group of harmatomatous disorders called the
PHACOMATOSES
• ‘Drug induced’ -Amiodarone and- also a cause of
corneal verticillata
• Iatrogenic- Corticosteroids (posterior subcapsular)

11. Corneal verticillata

12. Secondary
• Associated with Retinitis Pigmentosa
• Uveitis- intraocular inflammation
• Glaucoma, Corneal graft, vitreoretinal and any intraocular
surgery
• Congenital
• Hereditary disorders
• Maternal rubella
• Systemic disease e.g. galactosemia
• Myotonic Dystrophy
• Chromosomal
• Trisomy 13 (Patau’s syndrome)
• Trisomy 18 (Edward’s syndrome)
• Trisomy 21 (Down’s syndrome)

13. Symptoms of cataract
• Glare
• Gradual loss of vision unless traumatic
• Reduced near vision i.e. difficulty reading - seen in
posterior subcapsular type
• Central lens opacities may decrease pinhole vision
• Second sight - nuclear cataracts cause changes in
refractive index of lens so that they become more
myopic and one may not need reading lasses
• (Normally when one ages one becomes more
presbyopic, i.e. near-sighted requiring more plus lens)

14. Examination
• Pen torch- red reflex
• Ophthalmoscopy (direct)- red reflex vs. black
opacities in pupil area
• Slit lamp examination distinguishes the
cataract subtype.

15. Red reflex with pen torch and note the
white cortical lens opacities

16. Treatment
• Surgical treatment is the only definitive treatment to
remove a cataract
• Indications for and against surgery
• The aim of cataract surgery which is for the most part an
elective procedure is visual rehabilitation
• Reasons ‘AGAINST’ surgery
• Anaesthetic risk e.g. if unsuitable for LA but GA risk high
• Severe amblyopia already investigated and documented
• Extensive age-related macular degeneration or other retinal
pathology
• Total afferent pupillary defect

17. Other reasons for lens extraction
• Clear lens extraction may be performed- i.e. no significant
cataract present but lens may need to be removed
• Severe myopia
• Patients may elect to have this done at an early age rather than wait
to have cataract develop therefore avoiding need for thick
spectacles or contact lenses
• Dislocated lenses
• Pseudoexfoliation- can sometimes have associated glaucoma and
systemic manifestations with this
• Trauma
• Systemic conditions
» Marfan’s- typically upward dislocation of lens
» Homocysteinuria typically downward dislocation of lens
» Weill-Marchesani
» Sulphite-oxidase deficiency

18. Dislocated lens in Trauma

19. Downward dislocation of lens can be
seen in homocysteinuria

20. Types of Anaesthesia
• Local- most common
• Topical anaesthetic drops
• Retrobulbar, peribulbar, sub-Tenon’s injections
of local anaesthetic
• General (e.g.)
• Children
• Handicapped
• Parkinson’s disease
• Nystagmus

21. Types of cataract surgery
• Intracapsular
– Rarely done
– Removal of lens and capsule
– Anterior chamber intraocular lens used
• Extracapsular cataract extraction
– Removal of lens but capsule left behind

22. Phacoemulsification
• The most common type of extracapsular surgery today is :
Phacoemulsification- ultrasonic lens fragmentation with
simultaneous aspiration of lens fragments
– Sophisticated small incision type (approx. 2.7-3.5mm wound
incision)
– Faster visual recover with fewer complications
– Suture not routinely place
• In Extracapsular surgery:
– The intraocular lens is inserted into the capsule either by injection or
unfolding
– If posterior capsule significantly damaged during surgery or deemed
to be unstable lens may be inserted in the sulcus- space between
iris and anterior capsule or alternatively into the anterior chamber.
The latter must occur in conjunction with a peripheral iridotomy

23. Intraocular lens

24. Other
• Can combine cataract surgery with:
– Glaucoma surgery
– Corneal graft surgery
– Other surgery

25. Post-operative care and visual
rehabilitation
• Combined steroid and antibiotic eye drops to be
tapered over 4 weeks
• See at 1 day, 2 weeks and 1 month post-
operatively
• If have artificial lens (pseudophakic) will need
reading glasses post-operatively as no
accommodation
• If no lens in eye (aphakic) correct with
spectacles or contact lens
• Thickening of posterior capsule i.e. an ‘after
cataract’ treated with YAG laser

26. Posterior capsular thickening with YAG
laser capsulotomy

27. Laser Eye Surgery
• Excimer laser
• Therapeutic- removal or superficial cornea in
recurrent erosions
• Refractive
– LASIK or Laser assisted in situ keratomileusis
– LASEK or Laser assisted epithelial keratomileusis
– PRK OR ASA or Photorefractive keratectomy or Advanced
Surface Ablation
Refractive Surgery may be used to correct Myopia,
Hyperopia and Astigmatism

28. VIDEO OF PHACOEMULSIFICATION