Management of paediatric cataract DrBP

1. Management of pediatric cataract.. Dr. Bhushan Patil

2. Childhood cataracts are responsible for 5% to 20% of blindness in children worldwide and for an even higher percentage of childhood visual impairment in developing countries. The prevalence of childhood cataract varies from 1.2 to 6.0 cases per 10,000 infants. Cataracts in children not only blur the retinal image but also disrupt the development of the immature visual pathways in the central nervous system. Hence timely removal of cataract followed by prompt visual rehabilitation is of utmost importance in children.

3. History.. Careful history including a family history from the parents. • Ask about any illnesses or drugs used during the Pregnancy • Find out if the child is developing normally • Child should be examined by a paediatrician, to look for other congenital anomalies

4. Ocular examination Visual acuity Preverbal child: Fixation behavior A baby can hold fixation on a target & follow it around in the space as the target moves,in a normally illuminated room- ‘ fix&follow ’ CSM method: central, steady, and maintained fixation on a target. If each eye fixates centrally rather than eccentrically, holds steady fixation on that target rather than searching for it or wandering, and continues to stay fixated on that target even when occlusion is removed from the fellow eye, the vision is noted "CSM".

5. Preferential looking- Teller’s acuity cards uniocularly & binocularly

6. Optokinetic nystagmus : It is a rapid screening method for gross integrity of visual pathway. Optokinetic response is generated with the use of moving field stimulus which induces pursuit movement. OKN is an involuntary pursuit response to moving stripes. A child with some vision will demonstrate a nystagmus as the stripes moves across the field of veiw .( catford drum)

7. Visual evoked potential: It measures EEG pattern created by visual stimuli. Electrodes are placed on the occipital region & visual stimuli-bright flash square wave/phase alternating checker boards,shown to child. Response is compared with age matched controls.

8. Verbal Child -preschool(2-5yr) 2yr old child can easily match simple forms & responds well to learning through demonstration. Visual acuity testing – matching task. The child has to find out the matching block or point to the shape that matches the target kept at a distance of 3meters.

9. Lea symbol charts HOTV test Landolt C rings Tumbling E Cardiff acuity test >5yrs : Snellen visual acuity charts.

10. Slit lamp biomicroscopy Density, size,morphology &location of cataract. Associated anomaly: Aniridia Microcornea Coloboma Persistent pupillary membrane. Dilated fundus examination & USG- Bscan

11. Biometry & IOL power calculation At birth axial length of globe is 16 mm and increases to 20 mm on the completion of 2 years. At birth the human lens is more spherical than in adults. It has a power of about 30D, decreases to about 20-22D by the age of five i.e . Myopic shift . This means that an IOL which gives normal vision to an infant will lead to significant myopia in adulthood. These changes are most rapid during the first few years of life and this makes difficult to predict the correct power of lens for any child.

12. There is also change in size of capsular bag from 7mm at birth to 9mm at 2 years. An ideal IOL power should aim at prevention of amblyopia in childhood and least possible residual refractive error in adult. Undercorrect the IOL power at the time of surgery to prevent significant myopia later. Keratometry - handheld keratometer A-scan-immersion technique.

13. Formulas 1.SRK/T : AL > 26mm 2.Holladay II : AL 24-26mm 3.Hoffer Q : AL < 22mm age undercorrection Upto 2 yrs 20% >2 yrs 10%

14. Lab investigations: CBC BSL Urine proteins TORCH titres VDRL urine for reducing substances &red cell galactokinase sr.calcium & phosphate karyotype

15. Indications of surgery Visually significant central cataracts Dense nuclear cataracts Cataract a/w strabismus Cataract obstructing examiners view of the fundus

16. Timing of surgery Bilateral cataract 1.Bilateral dense • Early surgery – before10 wks of age • To prevent simultaneous deprivation amblyopia . • Denser eye should be addressed first 2. Bilateral partial • Monitor lens opacity and visual function • Intervene latter if vision deteriorates.

17. Unilateral cataract 1. Unilateral dense • urgent surgery with in 6 wks. • Followed by aggressive anti- amblyopia therapy 2. Unilateral partial • Can be observed or treated non-surgically with pupillary dilatation and possibly part time contra lateral occlusion to prevent amblyopia .

18. Pediatric cataract surgery differs from adult: Small size of eyes Highly elastic anterior capsule Low scleral rigidity Dense vitreous Propensity for severe post-op inflammation Constantly changing refractive status Tendency to develop amblyopia

19. Surgical techniques: Lensectomy + primary posterior capsulotomy & anterior vitrectomy with/without primary IOL implantation. Primary IOL implantation in infants – controversial -high tissue reactivity -marked changes in AL & Refractive status. Safe & effective alternative to contact lens/ spects . Aids amblyopia treatment by eliminating period of uncorrected aphakia .

20. Pars plana Lensectomy - if no IOL implantation is planned. Performed through pars plana incision with vitreous cutting instrument/manual aspirating device. Disadvantage- capsular bag is not preserved, so in-the-bag IOL implantation is not possible. Limbal lensectomy – Most preferred approach especially when primary or secondary IOL implantation is planned.

21. If IOL is being implanted-partial thickness scleral incision , 2-2.5 mm from limbus or a clear corneal incision. Scleral tunnel- preffered - maintains AC & prevents iris prolapse . 2. Management of anterior capsule: Manual continuous curvilinear capsulorhexis using Uttrata forceps. Anterior capsule in tough & elastic

22. It is facilated by using highly retentive viscoelastic e.g.Healon GV, force lens posteriorly and reduce its anterior convexity-combat the effect of vitreous upthrust. Anterior capsule-stained with Trypan blue. Small CCC – 5mm diameter. Capsular flap is frequently released to inspect size,shape & direction of the tear.

23. More pull is needed centripetally to avoid extension of CCC. 2 incision pull-push technique: 2 small incisions superior & inferior Grasp the centre of flap of superior incision & push towards centre-semicircular tear. Grasp the centre of flap of inferior incision & pull towards centre-semicircular tear.

24. Vitrector,Radiofrequency diathermy, Fugo plasma blade. Manual continuous curvilinear capsulorhexis is gold standard.

25. 3.Lens matter is aspirated by using vitreous cutter or a Simcoe cannula . 4. Primary IOL is implanted in the bag for long term stability & safety. children < 2yrs :Downsize IOL to 10mm diameter. To prevent- capsular bag stretching-PC folds. Lens epithelial cells migrate towards the visual axis through folds-PCO.

26. Single piece acrylic IOL is best,less capsulorhexis ovaling & capsular bag stretch. PMMA IOL can be used. 5.Management of Posterior capsule: Child < 5 yrs Primary Posterior capsulotomy + anterior vitrectomy to prevent opacification . Manually or vitrector

27. Children > 5yrs: PC left intact Nd:YAG laser posterior capsulotomy in early post-op period. Intraop miotics -avoided-to prevent ant.segment inflammation. Use of LMW Heparin(5IU in 500ml) irrigating solution reduces ant.segment inflammation. Low scleral rigidity-wound is not self sealing-fish mouthing. Suture the wound at the end.

28. Visual rehabilitation Spectacles Useful for older children with bilateral aphakia In infant inappropriate because of weight, unpleasent appearance, prismatic distortion and constriction of visual field. Contact lenses Provide superior optical option for unilateral aphakia Tolerance is reasonable until the age of 2 years CL become dislodged leading to period of visual deprivation with the risk of amblyopia .

29. Part time occlusion of better eye in cases of unilateral cataract. IOL implantation Performed in younger children and even infant. Most effective and safe. Piggyback IOL in infants-temporary polypseudophakia . Post.lens -in the bag; ant.lens-ciliary sulcus 1-2 yrs after surgery,ant lens is explanted/exchanged.

30. Post-op Complications 1. Uveal inflammation: Common complication-increased tissue reactivity in children in early post-op period. Uveitis -membrane formation,pigment deposition, Posterior synechia . topical & systemic steroids.

31. 2.Glaucoma glaucoma occur in the immediate post operative period is secondary to pupil block or PAS formation esp in small eyes. Glaucoma may occur after lensectomy , if it is carried out in the first week of life. This glaucoma is very difficult to treat and frequently leads to blindness. Delaying surgery until after the child is 3-4 months old makes it unlikely that the eyes will recover 6/6 vision but it reduces the risk of glaucoma

32. Open angle glaucoma- commonest type Occur about 7 years after surgery. The mechanism of glaucoma is not exactly understood. decreased incidence of open-angle glaucoma in pseudophakic eyes compared to aphakic eyes after cataract surgery. Probably, the IOL acts as a barrier between the vitreous and trabeculum , preventing a vitreous chemical component from acting on the trabeculum .

33. Vision threatening complication, IOP should be recorded periodically. Every 3monthly-1 st postop yr Twice yearly- 10 th yr Once yearly thereafter. Glaucoma filtering surgery/ drainage implant is often require to control the IOP.

34. 3. Posterior Capsular opacification : Late onset,begins 18months after surgery Nearly universal if posterior capsule retained More significance in younger children because of more amblyogenic effect Opacification of anterior hyaloid face may occur despite capsulorhexis if the anterior vitreous is left intact. Nd:YAG laser capsulotomy .

35. Proliferation of lens epithelial cells with in the remnants of anterior and posterior capsule and is referred as Soemmerring ring.

36. 4.Secondary membrane. Late onset In the pupillary region Fibrinous post operative uveitis in normal eye unless vigorously treated may also result in membrane formation. Thin membrane opened with Nd:YAG laser Thick ones may require membranectomy .

37. 5.Pupillary capture Commonly seen in children <2yrs,size of optic less than 6mm, IOL placed in ciliary sulcus . Left untreated if asymptomatic. Retinal detachment,CME -less common complications

38. THANK YOU…