OPTOMETRIST'S ROLE IN PEDIATRIC CATARACT

this was presented on third year of optometry as a project presentation

1. ROLE OF OPTOMETRIST IN PEDIATRIC CATARACT

2. CONGENITAL CATARACT Congenital cataract represents a transparency disorder of the lens present at birth or soon after. It is one of the main causes of treatable blindness or visual impairment in children. In literature, its prevalence is 1–6 cases/10 000 births in economically developed countries and 5–15/10 000 births in the developing world . WHO estimates that there are over 14 million blind children worldwide, originating in bilateral cataract, i.e., over 50% of the causes of blindness .

3. Congenital v/s Developmental cataract Congenital and developmental cataract are not synonymos . Most forms of cataract( even senile cataract) may be considered as developmental ,for human lens grows until late in life. Criteria for congenital cataract? If size of the lens opacity is more than 5.75 mm, cataract may be Postnatal.

4. Morphology of congenital cataract Long, Erping & Lin, Zhuoling & Chen, Jingjing & Liu, Zhenzhen & Cao, Qianzhong & Lin, Haotian & Chen, Weirong & Liu, Yizhi . (2017). Monitoring and Morphologic Classification of Pediatric Cataract Using Slit-Lamp-Adapted Photography. Translational Vision Science & Technology. 6. 2. 10.1167/tvst.6.6.2.

5. “Examination, diagnosis and treatment of paediatric cataract are only the first steps of a multi-faceted visual rehabilitation journey. Close collaboration between the patient, parents and the wider ophthalmic team is vital in achieving the best visual prognosis”

6. OPTOMETRIC APPROACH

7. PRE SURGICAL APPROACH

8. 1.HISTORY TAKING OCULAR HISTORY As provided by the parent Visual status: Ambulation in familiar & unfamiliar surroundings? Deviation of eyes? To & fro Eyeball movements? Any type of white reflexes in the eye ? Behavioural pattern & school performance ?

9. BIRTH HISTORY History of maternal infection during 1 st trimester? APGAR score? Gestational age & birth weight? Birth trauma? Supplemental O2 therapy in perinatal period? Developmental milestones?

10. FAMILY HISTORY History & Degree of consanguinity? Family history of congenital cataract? The family tree of the patient pedigree and cataract phenotype: ( A) The four-generation 24-member pedigree with dominant congenital cataract. ( B) Varied cataract types and severity in patients. Photographs of eyes of two patients were shown. Patient III:6 has bilateral total cataracts. Patient III: 11 has a nuclear cataract in the right eye and a zonular cataract in the left eye. Jin, Aixia & Zhao, Qingqing & Liu, Shuting & Jin, Zi -Bing & Li, Shuyan & Xiang, Mengqing & Zeng, Mingbing & Jin, Kangxin . (2022). Identification of a New Mutation p.P88L in Connexin 50 Associated with Dominant Congenital Cataract. Frontiers in Cell and Developmental Biology. 10. 794837. 10.3389/fcell.2022.794837.

11. SYSTEMIC HISTORY

12. 2.COMPLETE OCULAR EXAMINATIONS GENERAL EVALUATION

13. VISUAL ACUITY MEASUREMENTS INFANTS TODDLERS PRE-SCHOOLERS SCHOOLERS HOW VISUAL ACUITY MEASUREMENT IN PEDIATRIC PATIENT IS DIFFERENT THAN ADULTS?

14. REFRACTION Preoperative refraction determines the estimated power of the intraocular lens to be implanted during cataract surgery. Retinoscopy may also be used to detect the morphology and sometiomes may act as DDO.

15. 1.Objective refraction in pediatric patients:

16. CHOICE OF REFRACTION FOR DIFFERENT AGE GROUPS

17. SPECIAL CONSIDERATIONS AGE & DEVELOPMENTAL STAGE Refraction techniques need to be adapted based on the child’s age and developmental stage. Infants may require non-verbal methods of assessment while older children may participate more actively in subjective refraction. ASSESSMENT OF ASSOCIATED CONDITIONS Children with congenital cataract may have additional ocular and systemic conditions that can affect refraction. it’s is essential to consider these factors and tailor the refraction process accordingly.

18. CYCLOREFRACTION MEASUREMENTS TO BE DONE BEFORE INSTILLATION Pupillary reflex and size under room illumination. Hyperemia in conjunctiva. Manifest refraction. Binocular status. General strabismus evaluation. Ac angle and IOP if possible. Importance of cyclorefraction in congenital cataract?

19. While there isn’t a specific study or guideline that states that cyclorefraction is not typically performed in cases of congenital cataract, the rationale for this practice is based on clinical experience, safety considerations, and the challenges associated with performing cyclorefraction in infants and young children with cataracts. Safety concerns Limited cooperation Diagnostic challenges Alternative methods

20. SLIT LAMP EXAMINATION External eye examination including lids and lashes. Measurement of intraocular pressure. Associated congenital anomalies of iris & lens . Morphological evaluation of cataract with slit lamp under EUA whenever possible . Iridodenesis / phacodonesis Dilated examination of cataract & fundus.

21. 3.INVESTIGATIVE PROCEDURES B-SCAN: If there is a view of the retina, full retinal examination documenting optic nerves, retina, and fovea is performed. If there is no view, ultrasonography (B-scan) is carried out. Performed to evaluate for any posterior pathology such as a retinal detachment, persistent fetal vasculature, or posterior pole tumor.

22. OCULAR BIOMETRY

23. AXIAL LENGTH MEASUREMENTS APPLANATION IMMERSION Indentation of cornea Decreased corneal and scleral rigidity Accurate Perpendicular to retina (Gold Standard)

24. IMPORTANT DETAILS TO BE KEPT IN MIND WHILE AL MEASUREMENTS Velocity( phakic / aphakic / pseudophakic ) A-constant Ensure good quality reading

25. Possible errors in AL Measurement Most significant factor leading to incorrect selection of IOL power. Young children are not co-operative and constantly moving. Difficult in office setting. EUA, lack of fixation. Error jumps from 2.50 D in adults to 3.75 D per mm in short eyes. Thus, in case of contact tonometry,must rely on measurement with greatest ant.chamber depth.

26. KERATOMETRY

27. OPTICAL BIOMETERY Highly accurate,non -invasive automated method with higher reproducibility. Uses light partial coherence interferometry (PCI). The newer biometry devices produces several biometric parameters,namely ; AL, K READING, CCT, PS, ACD, LT, VD, WTW.

28. OPTICAL BIOMETERS AND THE TECHNOLOGY USED

29. IOL POWER FORMULAS (AT A GLANCE)

30. Recently Koch et.al (JCRS2017) a new classification of IOL power formulae based on (a) Method of calculating IOL power. (b) The data used for these calculations.

31. FACTORS INFLUENCING ACCURACY IN PEDIATRIC IOL POWER CALCULATION AL and KM reading errors. Supine positions used for examinations. Instruments designed for adult eyes. Adult formulas used. Cataract extraction with posterior capsulotomy and anterior vitrectomy may affect the effective lens position. Target refraction and growing myopic shift.

32. Newer generation formulae are superior to earlier formulae. They predict better ELP. The popular new generation formulae include HOLLADAY 2, BARRETT UNIVERSAL II, AND THE HILL-RBF. Vasavada et al(2016) conducted an observational study and proved with statistically significant data that: SRK/T and HOLLADAY 2 had least prediction error(PE) in pediatric eyes. Personalizing the lens formulae constant reduced the PE significantly. In eyes <20mm,SRK/T and HOLLADAY 2 gave the best PE

33. TARGET POST OPERATIVE REFRACTION The ideal IOL power should give: *The best help for fighting Amblyopia. *Inducing the Least Refractive error in adulthood. IOL power can be calculated by anticipating the expected myopic shift and undercorrecting . How much should one undercorrect ?

34. TARGET POST OPERATIVE REFRACTION Determining a post-op refraction is a multifactorial approach most importantly influenced by : Age at cataract surgery Other factors include: Status of the fellow eye Visual acuity Expected compliance Parent’s refractive error IOL power Microphthalmia Trivedi &wilson2006 updated 2016

35. Age at cataract surgery 2 approaches can be used : Prost suggested 20 % undercorrection - 1&2 years. 15 % undercorrection - 2 & 4 years. 10 % - 4 & 8 years of age

36. INTRAOPERATIVE IOL CORRECTIONS If a decision regarding the site of fixation needed to be changed after opening an eye and before implantation- an appropriate adjustment may need to be made. Sulcus fixation produces a relative myopic shift from the estimated refraction. IOL power can be decreased by 0.75D-1.00D when placed in the cilliary sulcus.

37. IOL implantation in Infants INFANT APHAKIA TREATMENT STUDY(IATS) Children enrolled in the treatment study who underwent IOL implantation were evaluated for the refractive changes at 5 years of age . It showed that the rate of myopic shift occurs most rapidly in the first 1.5 years of life. It was suggested that the goal for emmetropia by 5 years,the immediatiate post-operative hypermetropia target should be : +10.50 D at 4-6 weeks +8.50 D from 7 weeks-6 months

38. Aparna ramasubramanian MD,AAO October 2019 article included in clinical education . Infants less than 6 months should be left aphakic . For children older than 6 months,the decision should be based on the surgeon’s level of experience and the patient’s individual characteristics. The authors analyzed multiple studies, which inherently introduces bias. Only 1 study ( i.e ; IATS) provided level 1 evidence on IOL implantation in early childhood.

39. In this era of recent advances Increasing trend to IOL implantation in infants Target hyperopia to avoid myopic shift Careful measurements to avoid errors in AL/K Newer IOL calculation formulae Best calculation is still awaited !!!

40. NON SURGICAL MANAGEMENT Used for partial cataracts < 3mm and pericentral cataract respond. Pupillary dilatation with 2.5% phenylephrine and part time occlusion of good eye. Cyclopentolate can be added once or twice a day if required. Pupillary dilatation is reserved for preverbal with partial cataracts and borderline amblyopia. If significant amblyopia persists, cataract extraction should be performed.

41. SURGICAL TREATMENT Threshold/indication for surgery Dense cataracts that block the red reflex before the pupils are dilated and are associated with abnormal visual behavior should be removed during infancy . Other signs suggestive of visually significant cataracts are strabismus in a child with a unilateral cataract or nystagmus in a child with bilateral cataracts. Visual acuity chart threshold for surgery Visual dysfunction weighed against post-op loss of accommodation Immediate sequential bilateral cataract surgery for children

42. Timing and critical period In the 1960s, Hubel and Wiesel   introduced the concept of a “latent period” and a “critical period” for visual development. During the latent period, visual deprivation has no lasting effect on vision in the deprived eye. After the latent period, there is a critical period during which visual deprivation results in irreversible vision loss in the deprived eye. The critical period for a child with a cataract extends to age 9-10 years.

43. UNILATERAL CATARACT The optimal age for performing cataract surgery is agreed to be 6 weeks of age . BILATERAL CATARACT It is generally agreed that bilateral congenital cataracts should be removed by 8 weeks of age to achieve the best visual outcomes. Lambert and coworkers  noted that delaying cataract surgery to 10 weeks of age or later increased the likelihood of a 20/100 or worse visual outcome . However, after age 14 weeks until 31 weeks, the visual outcome was independent of the child’s age at the time of cataract surgery.

44. POOR PROGNOSTIC INDICATORS Ocular alignment and motility Strabismus Manifest latent nystagmus Anterior segment HCD, dysgenesis-aniridia, corneal dystrophy, anterior cleavage syndromes, lens anomalies- microspherophakia Posterior segment Choroideremia, RP, PHPV, vitreo retinal degenerations- Wagner’s

45. SURGICAL TECHNIQUES EXTRACAPSULAR CATARACT EXTRACTION INVOLVING ANTERIOR CAPSULORRHEXIS & LENS ASPIRATION LENS ASPIRATION COMBINED WITH PRIMARY POSTERIOR CAPSULOTOMY>6 YRS & WITH ANTERIOR VITRECTOMY IN ALL CHILDREN >2 YEARS.

46. POST SURGICAL APPROACH VISUAL REHABILITATION

47. 1.SPECTACLES In some children with bilateral aphakia spectacles are better tolerated than contact lenses. In addition, secondary strabismus may be manipulated by prismatic effect of spectacles . Cosmetically not acceptable. Bifocal glasses should be prescribed when the child is about to start school.

48. TYPES OF GLASSES Single vision glasses Near dominant glasses Bifocal glasses Progressive glasses

49. 1.Single vision glasses Normal distance glasses. 2.Near dominant glasses < 3 year of age operated for cataract. <1 year (+3.00) 1-2 year(+2.00) 2-3 year(+1.00) >3 year (+3.00 D , Executive bifocals)

50. 3.Bifocal selection in pediatric patient Pseudophakia / cp /Down’s syndrome: near segment sould co- incide with lower limbus . Esotropia with high AC/A ratio: Near segment should bisect the pupil.

51. 4 .Progressive glasses Pseudophakia > 3 yrs of age operated for cataract Progression of myopia Homide with near addition for reading Lag of accommodation Down’s syndrome

52. Dispensing spectacles and measurements

53. Frame considerations Titanium is the ideal material. Cellulose acetate,polyamide and optyl are plastic materials. Silicone based rubber frames for children who require indestructible frames. Lens selection Ideally should provide full uv protection. Relatively thin. Impact resistance and durable.

54. Aphakic glasses considerations

55. 2.CONTACT LENS If no IOL is implanted, contact lenses are given as early as possible to prevent stimulus deprivation amblyopia. Allow changes for visual correction with IOL upon visual maturity. Frequent retinoscopy is performed to decide the power of CL and an overcorrection of +2 to +3D is mandatory. Available in Silicone Elastomers,Hydrogels & RGP. Considerations : power changes Need for supplementary spectacles Wound healing, ocular medications systemic medications , compliance

56. Fitting contact lens in pediatric More success rate. Using contact lens for few years and having IOL implant later c ould work better. There was no difference in the vision between the eyes treated with CL compared to IOL. But the IOL group had more complications and required more eye surgeries(IATS). Challenges and complications Too frequently lost , relatively expensive Time consuming and difficulty in handling Non-compliance and greater risk of infection Failure of treatment is directly related to the treatment of amblyopia, and not related to the fitting and wearing of contact lenses.

57. 3.AMBLYOPIA MANAGEMENT Early diagnosis,surgery,appropriate refractive error correction, amblyopia therapy and long-term follow-up are essential. It is well known that recovery of normal visual function after cataract surgery is more probable in adults as compared to children due to impairment of the developing visual system. Amblyopia occurring due to post-operative refractive error which the child has, destroy the benefit obtained by a near perfect & timely surgery. Occlusion therapy, combined with wearing spectacles and implanting IOLs, is valuable in treating deprivation amblyopia due to ocular trauma and series surgeries in pediatric patients.

58. PREVENTION Evaluation of the red reflex is essential not only in the newborn nursery, but also in subsequent pediatric office visits to identify and address the potential presence of a congenital cataract in a timely manner.

59. LONG TERM MONITORING After surgical management of visually significant cataracts, patients require lifelong follow up. Throughout childhood, frequent monitoring and management of refractive error, amblyopia, and possible glaucoma is necessary. Patients with congenital cataracts that are not visually significant also should be monitored to ensure that the cataracts do not progress to become visually significant.

60. TAKE HOME MESSAGE The paediatric cataract is multi-faceted in terms of age of onset, morphology, associated disease and risk factors. Early diagnosis and treatment can help to avoid long-term adverse sequalae such as amblyopia and strabismus, but have different associated risks depending on treatment initiated. Visual rehabilitation with adequate compliance can have a great deal of benefit in improving visual acuity and binocularity, but must be tailored to the individual and family for optimal results .