Aphakic Optical Correction with Intraocular Lenses for Children with Traumatic Cataracts DAVID A. HILES, KENNETH P. CHENG and ALBERT W. BIGLAN

Department of Ophthalmology, University of Pittsburgh School of Medicine, USA

Two hundred and thirty-eight children, all but one with unilateral traumatic cataracts, were treated by our paediatric ophthalmology group between 1974 and 1988. One hundred and seven­teen patients received IOLs, 86 received contact lenses, three received glasses, 14 had epikeratop­lasties and 18 patients received no correction because of the marked reduction in vision following the initial trauma.

Three designs ofiOLs were implanted: 79 iris suture IOLs between 1974 and 1981, followed by 28 anterior chamber and 20 posterior chamber IOLs implemented between 1981 and 1988. The inci­dence of preoperative complications was 59%. Secondary operations were somewhat more fre­quent for IOL-containing eyes at 51%, but less than epikeratoplasty eyes at 79% and more than contact lens or glasses rehabilitated eyes at 41 and 33% respectively. Iris-supported IOLs required more secondary surgery, but these were often related to the occurrence of secondary membranes which were routinely opened at a second operation.

The visual results were equal for patients receiving contact lens and IOLs even with a skewed case selection. Patients receiving primary IOLs had a better visual result than those patients receiving secondary IOLs because of time lost before the IOL was implanted and before amblyopia therapy was begun. Children over 8 years at the time of injury also achieved far better visual results because of the presence of visual maturity.

Keywords: Traumatic cataracts; Iris suture IOL; Anterior chamber IOL; Posterior chamber IOL

INTRODUCTION

The concurrence of traumatic cataracts is by no means a rarity among the paediatric population throughout the world. Lenticular damage, usually unilateral and occurring mostly in boys, remains the commonest complication causing visual loss follow­ing all types of ocular injury. This tragedy is com­pounded by the additional threat of visual loss secondary to deprivation amblyopia in the eyes of visually immature children. Associated corneal, cor­neoscleral angle, vitreal, retinal and optic nerve injuries further compound the management of these

This study was supported in part by grants to the Fight For Sight Children's Eye Clinic of Children's Hospital of Pittsburgh, Penn­sylvania, by Fight for Sight, Inc., New York (Drs Hiles, Biglan and Cheng). This paper was presented at the Seventh European Intraocular Lens Implant Council, Zurich, Switzerland, 29 August 1989.

Please address all correspondence to: Kenneth P. Cheng, 3518 Fifth Avenue, Pittsburgh, PA 15213, USA.

0955-3681/90/040275+09 $03.00/0 © 1990 Bailliere Tindall

patients and may severely compromise the child's aphakic visual prognosis.

Lens injuries occur by contusion or direct force applied to the globe without laceration, concussion or shaking of the globe with a transfer of external energy to the globe with rupture of internal tissues, or by penetration of the globe with direct trauma to the ocular contents.

It is the purpose of this paper to review our man­agement of children with traumatic cataracts. We include suggestions for preoperative evaluation of the traumatized eye, our surgical indications for cataract extraction, and our indications and contra­indications for the implantation of an intraocular lens (IOL). We shall review our series ofiOL implan­tations including the complications and secondary surgeries promulgated by this technique. The visual results achieved by these children will be reviewed and compared with other methods of aphakic optical correction for children following traumatic cataract surgery.

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PATIENTS AND METHODS

A consecutive series of 238 eyes with traumatic cataracts, all but one unilateral, who were treated by our paediatric ophthalmic practice between 197 4 and 1988 were reviewed. One hundred and ninety-four (82%) were boys. One hundred and fifty-seven (66%) patients were less than 8 years of age at the time of injury. The duration offollow-up ranged from two to 16years.

Eighteen (8%) eyes of our series of traumatic catar­act patients did not receive aphakic optical correction because other severe ocular injuries precluded useful vision. Three (1 %) patients, one with binocular injur­ies, received glasses. Contact lenses were prescribed for 86 (36%) patients and 14 (6%) patients received epikeratoplasty grafts. One hundred and seventeen (49%) of the eyes received IOLs for aphakic optical correction.

Intraocular lenses were implanted at the time of the cataract extraction, or primary implantation, in 85 (73%) eyes (Table 1). Secondary implantation at a time remote from cataract extraction was performed in 32 (27%) eyes. Iris-supported lenses were implanted in 79 (68%) eyes between 1974 and 1981. Between 1981 and 1988, 18 (15%) anterior chamber lenses and 20 (17%) posterior chamber lenses were implanted.

Ocular pathology related to the injury, besides the presence of the traumatic cataract, included corneal scars, glaucoma, traumatic uveitis, detached retinas, choroidal tears, optic atrophy and iris complications of traumatic colobomas, synechiae, adherent leuko­mas, dialyses, and sphincter tears (Table 2). Forty­seven (59%) eyes receiving iris-supported IOLs had

Table 2 Preoperative complications and aphakic modalities

D.A. Hiles, K.P. Cheng, A.W. Biglan

Table 1 Primary and secondary implants of intraocular lenses (1974-1988)

Number of eyes(%) Total Primary Secondary

Iris-supported 79 (68) 57 (72) 22 (28) (1974-1981) Anterior chamber 18 (15) 10 (56) 8 (44) (1981-1988) Posterior chamber 20 (17) 18 (90) 2 (10)

Total 117 (100) 85 (73) 32 (27)

83 complications, 13 (72%) eyes receiving anterior chamber IOLs had 16 complications and 15 (75%) eyes receiving posterior chamber IOLs had 20 pre­operative complications.

The presence of preoperative complications in eyes rehabilitated with other modes of aphakic correction reveal that three complications occurred in two ( 66%) eyes in patients receiving glasses, 10 complications occurred in nine (64%) eyes in patients receiving epikeratoplasty, 83 complications occurred in 59 (69%) eyes in patients receiving contact lenses, and 30 complications occurred in 18 (100%) eyes which received no aphakic optical correction.

RESULTS

Postoperative complications consisted of corneal oedema, glaucoma, detached retinas, secondary membranes, dislocated IOLs, iris sphincter erosions, peripheral iris erosions or iris entrapment over a posterior chamber IOL. The occurrence of these com­plications with the different modes of optical aphakic rehabilitation is tabulated (Table 3).

Number of eyes with preoperative complications (%) Corneal scars Detached retina Glaucoma Iris defects Dislocated lens No. of % of eyes with

complicatonsl complications No. of eyes with complication

IOL designs Iris-supported 47 (59) 0 4 (5) 24 (30) 8 (10) 83/47 (59) N=79 Anterior chamber 9 (50) 1 (6) 0 5 (28) 1 (6) 16/13 (72) N= 18 Posterior chamber 13 (65) 0 1 (5) 5 (25) 1 (5) 20115 (75) N=20

IOLs (totals) 69 (59) 1 (1) 5 (4) 34 (29) 10 (9) 75173 (62) N= 117

Glasses 1 (33) 1 (33) 1 (33) 0 0 3/1 (33) N=3

Contact lenses 41 (48) 4 (5) 8 (9) 23 (27) 7 (8) 83/59 (69) N=86

Epikeratoplasty 8 (57) 0 0 1 (7) 1 (7) 10/9 (64) N= 14

No corrections 13 (72) 9 (50) 1 (6) 4 (22) 3 (17) 30118 (100) N= 18

Totals 119 (50) 15 (6) 15 (6) 96 (40) 38 (16) 270/170 (71) N=238

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Aphakic Optical Correction with IOLs 277

Table 3 Postoperative complications and aphakic modalities

Number of eyes with postoperative complications(%) Oedema Glaucoma Retina Defects Membranes IOLs No. of %of eyes with

complications/ complications No. of eyes with

IOLdesigns Iris-supported 10 (13) N= 79 Anterior chamber N= 18 Posterior chamber N=20

IOLs (Total) N= 117

Glasses N=3

2 (11)

0

12 (10)

0

Contact lenses 2 (2) N=86

Epikeratoplasty 0 N= 14

No correction N= 18

Totals N= 238

2 (11)

16 (7)

2 (3)

1 (6)

0

3 (3)

0

6 (7)

0

2 (11)

11 (5)

0

1 (6)

0

1 (1)

0

0

0

0

1 (.4)

13 (16)

2 (11)

0

15 (13)

0

1 (1)

0

1 (6)

17 (7)

Postoperative IOL complications occurred in 61 (52%) eyes. Forty-five (57%) eyes with iris-supported IOLs, seven (40%) eyes with anterior chamber IOLs and nine (45%) with posterior chamber IOLs had postoperative complications. These figures include the presence of secondary membranes in 44 (38%) pseudophakic eyes. Thirty-one (26%) aphakic eyes also developed secondary membranes. Prior to 1983, it was the accepted practice to retain an intact pos­terior capsule at the conclusion of the cataract oper­ation and to perform secondary capsulotomies at a later time.

Thirty (35%) eyes receiving contact lenses, one (33%) eye wearing glasses, and four (22%) eyes receiving no aphakic rehabilitation had post-catar-

Table4 Secondary surgeries and aphakic modalities

32 (41)

3 (17)

9 (45)

44 (38)

1 (33)

26 (30)

2 (14)

2 (11)

75 (32)

10 (13)

0

1 (5)

11 (9)

0

0

0

0

NA-

complications

67/45

9/7

10/9

75/61

111

35/30

2/2

7/4

111193

(57)

(40)

(45)

(52)

(33)

(35)

(14)

(22)

(39)

act surgery complications. Two (14%) eyes with epik­eratoplasty grafts developed secondary membranes following cataract surgery.

One hundred and fifty-nine secondary surgeries were required in 112 (47%) eyes of the series (Table 4). Ninety-three operations were performed on 60 (51%) pseudophakic eyes. Fifty-eight (73%) iris sup­ported IOL eyes, four (22%) anterior chamber and nine (45%) posterior chamber IOL eyes received secondary surgeries (Table 5). Forty-two operations were performed on 35 (41 %) contact lens rehabili­tated eyes, 14 operations on 11 (79%) eyes with epik­eratoplasty, two operations on one (33%) eye with glasses, and eight operations on five (28%) eyes receiving no aphakic rehabilitation.

Number of operations/ number of eyes

Secondary IOLs · Contact lenses EP!s Glasses No correction %of eyes surgery (N = 117) (N = 86) (N = 14) (N =3) (N = 18) with surgery

Capsulotomies 57/47 28/28 2/2 2/1 3/2 (32) Detached retina 111 0 0 0 111 (1) Glaucoma 2/2 6/4 0 0 0 (3) Enucleation 0 0 0 0 111 (.4)

Examinations under anaesthesia 0 7/6 111 0 4/1 (3)

Nd:YAGLasers 817 111 0 0 0 (3) IOL repositioning 20/12 0 0 0 0 (5) IOL explants 5/5 0 0 0 0 (2) EPI secondary surgeri surgeries 0 0 10/10 0 0 (4)

No. of eyes with secondary surgeries 93/60 42/35 14/11 2/1 8/5

% of eyes with secondary surgeries (51) (41) (79) (33) (28) (47)

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278 D.A. Hiles, K.P. Cheng, A.W. Biglan

Table 5 Secondary surgeries and IOL designs

Number of operations/number of eyes (%)

Iris supported Anterior Secondary chamber surgery (N = 79) (N = 18)

Capsulotomies 49/40 (51) 111 Detached retina 0 111 Glaucoma 111 (1) 1/1 Enucleation 0 0 Examination under

anaesthesia 0 0 Nd:YAG Laser 0 111 IOL repositioning 20/12 (15) 0 IOL explants 515 (6) 0

Totals 75/58 (73) 4/4

Table6 Best visual acuities for all optical modalities

Optical correction N 20120-20140

None 18 Glasses 3 Contact lenses 86 49 (57) IOL 117 68 (58) Epi 14 5 (36)

Total 238 122 (51)

These operations consisted of 101 discissions of secondary membranes or Nd:YAG laser capsuloto­mies, eight glaucoma procedures, two retinal detach­ment operations, one enucleation in an eye receiving no aphakic rehabilitation, 12 examinations under anaesthesia with or without contact lens fitting, 10 epikeratoplasty-related surgeries including suture removal and 20 IOL repositioning or suturing pro­cedures. Five explants were undertaken: three iris suture IOLs were removed without replacement and two additional iris suture IOLs were converted to anterior chamber IOLs.

One hundred and twenty-two (51%) patients in the series had best achieved visual acuities between 20/ 20-20/40, 33 (14%) eyes achieved 20/50-20/100 vision, 22 (9%) eyes achieved 20/200 vision and 61 (26%) had less than 20/200 visual acuity (Table 6). The visual results for each optical mode of aphakic rehabilitation are also recorded in this table. The visual results following primary and secondary IOL implantations are compared and the visual results are further subdivided by IOL design (Tables 7 and 8). The visual results in children who sustained lens

Posterior chamber Totals (N = 20) (N = 117)

(6) 7/6 (30) 57/47 (40) (6) 0 111 (1) (6) 0 2/2 (2)

0 0

0 0 (6) 3/3 (15) 817 (6)

0 20/12 (10) 0 5/5 (4)

(22) 10/9 (45) 93/60 (51)

Visual acuity, number ofpts (%)

20150-20/100 201200 <201200

18 (100) 1 (33) 2 (67)

16 (19) 8 (9) 13 (15) 12 (10) 13 (11) 24 (21) 5 (36) 4 (28)

33 (14) 22 (9) 61 (26)

injury at less than 8 years of age are compared with those whose injury occurred at ages greater than 8 years (Table 9).

Table 7 Best corrected visual acuity for primary and secondary IOLs

Visual Number of eyes(%)

acuities Primary Secondary Totals 20/20-20/40 53 (62) 15 (47) 68 (58) 20/50-20/100 9 (11) 3 (9) 12 (10) 20/200 8 (9) 5 (16) 13 (11)

<20/200 15 (18) 9 (28) 24 (21)

Totals 85 (100) 32 (100) 117 (100)

DISCUSSION

Based upon our experience with ocular trauma in children over the past 25 years, we have developed a treatment strategy for the visual rehabilitation of eyes with traumatic cataracts utilizing various types of optical devices as they have evolved. These devices have included aphakic glasses, a variety of contact

Table 8 Intraocular lens designs-best corrected visual acuities

Visual acuity, number of eyes(%) Total number

IOLdesign of eyes 20120-20140 20150-201100 201200 <201200 Iris supported 79 43 (55) 8 (10) 9 (11) 19 (24) Anterior chamber 18 8 (45) 2 (11) 4 (22) 4 (22) Posterior chamber 20 17 (85) 2 (10) 1 (5)

Total 117 68 (58) 12 (10) 13 (11) 24 (21)

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lens types, a series of IOL designs, and epikerato­plasty.

The assessment of the acutely injured child as well as the injured eye will determine what procedures are required to minimize visual loss following injury. A general history and physical examination deter­mines the presence of additional systemic injuries. Children suffering severe systemic injuries may require other surgical intervention prior to ophthal­mic surgery and the application of a protective film or plastic shield to the injured eye helps prevent further trauma to the eye until surgical repair is possible. Tetanus protection and systemic antibiotics, if appro­priate, should be instituted for patients with open globes or adnexal laceration.

The ocular assessment includes evaluation and documentation of the visual acuity or fixation reflex for each eye. Further examination of the ocular adnexa and globe may require either topical or general anaesthesia to accomplish in young children. Examination by indirect and direct illumination followed by, when feasible, slit lamp and indirect ophthalmic examination, corneal endothelial cell count and morphology evaluation, fluorescein stain­ing, applanation tonometry, ultrasonography, elec­troretinography, visual evoked responses, X-rays, computerized axial tomography, and magnetic reso­nance imaging are conducted when indicated. Surgi­cal exploration of the globe may be required to uncover occult scleral lacerations or rupture. Cul­tures are obtained from all eyes with open globes.

Cataract surgery is subdivided into 'immediate' requiring cataract extraction at the time of the initial wound repair, or 'delayed' when the cataract is removed at a time remote from the initial injury or ocular repair. The decision to implant an IOL into the eye of a child following injury is based upon the evaluation at the time of the injury or, more com­monly in our experience, at some more distant time following the lens injury.

Table 9 Corrected visual acuity vs. age at cataract onset

279

Immediate lens surgery is required for patients in which the lens capsule and lens have been damaged sufficiently to allow a release of lens cortical and nuclear material into the anterior chamber or vitreous. The free cortical material may incite a mas­sive inflammatory response with complications of uveitis, glaucoma, synechiae formation and phthisis bulbi. After the globe has been repaired, a superior limbal or pars plana cataract incision is made in a routine fashion for cataract surgery. Air, water, or preferably Healon ®' reconstitutes the anterior chamber. The lens is removed by aspiration-irriga­tion, phacoemulsification, or vitreous suction-cutting devices through the cataract incision. The anterior chamber is also cleared of blood, foreign bodies, iris debris and fibrin. Most commonly, cataract aspir­ation in children is combined with an anterior vitrec­tomy to clear the visual axis of all remaining lens elements, however, the surgeon may elect to preserve an intact posterior capsule for posterior chamber IOL implantation in patients old enough to co-operate for future Nd: Y AG laser capsulotomies.

At the conclusion of the initial wound repair and cataract extraction, a decision is made to implant an IOL. The most significant danger of IOL implan­tation at the time of initial repair in patients with open ocular wounds remains the potential for endophthalmitis. The presence of an IOL encased in an inflammatory membrane renders the visualiza­tion of the posterior segment impossible which further compounds the management of this and other complications.

In addition, the ability of the child's eye to with­stand the rigors of the initial trauma without excess­ive inflammation, to maintain normal intraocular pressures and retain a functioning corneal endothe­lium is also crucial in the IOL implantation equation. We therefore advise that it is more prudent to recon­stitute the globe following the initial injury, re­evaluate the eye as it heals and, if possible, delay

Visual acuity, number of eyes(%)

Subsets <8 years of age (N = 158)

Totals

>8 years of age (N = 80)

Totals

Optical modality

IOL(N= 85) Contact lenses (N = 50) Epikeratoplasty (N = 11) Glasses (N = 1) No correction (N = 11)

IOL(N= 32) Contact lenses (N = 36) Epikeratoplasty (N = 3) Glasses (N = 2) No correction (N = 7)

Eur J Implant Ref Surg, Vol2, December 1990

20120-20140 20/50-201100

39 (46) 12 (14) 24 (49) 12 (24) 2 (18) 4 (36) 0 0 0 0

65 (41) 28 (18)

29 (91) 0 25 (69) 4 (11)

2 (67) 1 (33) 0 0 0 0

56 (70) 5 (6)

201200

13 (15) 2 (4)

0 0 0

15 (9)

0 5 (14) 0 1 (50) 0

6 (8)

<201200

21 (25) 12 (24) 5 (45) 1 (100)

11 (100)

50 (32)

3 (9) 2 (6) 0 1 (50) 7 (100)

13 (16)

280 D.A. Hiles, K.P. Cheng, A.W. Biglan

Table 10 Visual acuities: a review of the literature

Visual acuity(% of series) Reference First author IOL series EPI series Year Number of 20120-20140 20150-201100 20/200and Unknown number (•) (**) eyes less 1 Juler 1929 21 51 10 39 2 Broendstrup 1944 48 29 13 58 3 McKinna 1961 52 15 6 77 2 4 Binkhorst * 1967 22 77 14 9 5 Binkhorst * 1969 26 85 8 8 6 Dreifus 1970 37 38 35 27 7 Ryan 1970 39 41 59 8 Bierlaagh 1971 29 79 17 3 9 VanBalen * 1972 27 74 15 11

10 VanBalen * 1973 47 70 23 7 11 Frey 1973 22 59 18 23 12 Scharf 1976 20 20 20 60 13 Frank 1977 12 58 17 25 14 Kearns 1977 20 35 20 45 15 Risse 1977 17 76 24 16 Davies 1977 8 12 50 38 17 Sjolie 1977 15 13 20 60 7 18 Roper-Hall 1977 32 44 16 40 19 Mondino 1978 3 33 33 33 20 Vaegan 1979 18 6 22 17 56 21 Maida * 1979 144 63 22 12 3 22 Mori * 1979 17 18 29 53 23 Binkhorst * 1979 73 77 12 10 1 24 Bores * 1980 13 69 23 8 25 Helveston 1980 16 44 19 37 26 Breebaart * 1981 10 80 20 27 Fyodorov * 1981 100 65 29 5 28 Parks 1982 7 71 29 29 Menezo * 1982 46 61 20 15 4 30 Singh * 1982 61 69 26 5 31 Jain 1983 28 64 25 11 32 Blumenthal * 1983 36 72 20 8 33 Sinskey * 1983 3 67 33 34 Schulman 1983 54 13 21 13 35 Bill ore 1983 20 55 15 30 36 Morgan ** 1983 8 25 50 25 37 Zaidman 1985 7 43 29 29 38 Morgan ** 1985 6 17 50 33 39 Jain 1985 28 68 28 4 40 Kushner 1986 3 100 41 Lewis 1986 30 73 20 7 42 Morgan ** 1986 18 22 39 39 43 Hemo * 1987 37 62 22 3 14 44 Villa-Coro 1987 4 75 25 45 Auni ** 1989 5 20 80 46 Insler * 1989 8 75 12 13 47 Hiles * 1989 238 51 14 35

cataract surgery and IOL implantation until a later niques. The visual indications for cataract surgery in time based upon the larger body of information able children are the development of a poor fixation reflex to be gathered in the post-injury period. For example, or vision below 20170, an increasing opacification of small anterior capsular perforations, even with the the cataract combined with a poor ophthalmoscopic presence of a small intralenticular foreign body, may view of the retina, or the onset of sensory strabismus. seal and produce only a very slowly developing lens It must be stressed that delayed lens surgery is com-opacity. This time lag is very important for the plica ted by the potential for deprivation amblyopia in visually immature child. It is more advantageous for visually immature children less than 8 years of age. vision to develop with an intact eye capable of The visual results are further compromised by the accommodation than it is with a unilateral aphakic age of the patient at the time of the initial trauma, eye. the rapidity oflens opacification between the time of

Delayed surgery, cataract and IOL implantation the injury and the age at cataract aspiration and lens procedures are based upon the patient's visual acuity implantation. or visual fixation reflexes and a preoperative assess- Delayed lens surgery affords the surgeon the ment of the eye using the above evaluation tech- opportunity to evaluate the eye and its healing capa-

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Aphakic Optical Correction with IOLs

bilities and to perform a controlled lens aspiration via either a limbal or pars plana incision.

The decision to implant an IOL, either as a primary procedure at the time of the cataract surgery or as a secondary procedure remote from the cataract extraction is based upon the condition of the eye and the age of the child at the time of implant surgery. This decision is further influenced by the potential for a clear visual axis through the cornea and vitreous, the absence of uncontrolled glaucoma or hypotony, the absence of intraocular infection or inflammation, the presence of a normal posterior pole and optic nerve, and the assessment of the ability of the young eye to withstand further surgical trauma. Additionally, traumatized corneas may have signifi­cant regular or irregular astigmatism which may require the use of a contact lens or epikeratoplasty graft to correct. A contact lens should also be con­sidered, but the problems of non-compliance or into­lerance to the use of a contact lens in a young child, particularly between the age of 2 and 4 years, may weigh in favour of an IOL.

The style of IOL implant is dictated by the child's perceived ability to tolerate the performance of a secondary Nd:YAG laser posterior capsulotomy. When this occurs, usually around age 6 years, a posterior chamber IOL is implanted if the posterior capsule is intact or has only a small central rupture. Particular attention must be directed to the attain­ment of adequate fixation. A Sinskey style soft J or C loop posterior chamber lens design with a 10 degree forward angulation of the loops may be implanted either in-the-bag, if the implantation is primary, or into the ciliary sulcus. There may be advantages to the use of one-piece all PMMA lens as opposed to a lens with prolene haptics. Large diameter, 6.5-7.0 mm ultraviolet blocking lenses are also advantageous.

An anterior chamber IOL is implanted into eyes of children 3 years of age and older when the posterior capsule of the lens has been lacerated or removed during the original trauma repair or with cataract surgery. If potential or actual corneal scars are peri­axial in location, the iris and corneo-scleral angle are intact, the pupil is movable, and vitreous is not present in the pupillary space or anterior chamber, an appropriately sized Kelman style multi-flex non­perforated four-pod, flexible single piece PMMA IOL is implanted. Preoperative gonioscopy is a valuable adjunct for assessment of the corneo-scleral angle for angle recession, iridodialysis or synechiae. Adequate placement by intraoperative gonioscopy and fixation of the IOL is crucial.

IOL powers are either empirically selected or cal­culated from keratometric, A-scan ultrasonography, anterior chamber depths or aphakic refractive error

Eur J Implant Ref Surg, Vo/2, December 1990

281

determinations. The average power of an anterior chamber IOL is 19 D and a posterior chamber IOL is 20 D. IOLs may be selected to produce emmetropia at the time of implantation, but optical errors of increasing magnitude may be induced with growth. If the power error becomes significant, an implant exchange may be required later in adolescence. We have followed the principle that the IOL power be suitable for an adult and allow the child to grow toward this goal. Post-implant refractive errors are corrected with spectacles into which are incorporated the residual sphere, cylinder and a suitable bifocal for near work.

Contraindications to IOL implantation include the presence of dense central corneal leukomas, severe irregular corneal astigmatism produced by irregular corneal scars, decreased corneal endothelial cell counts or function, uncontrolled glaucoma, poor IOL support systems for either anterior or posterior chamber IOLs, central retinal or optic nerve damage from trauma or the presence of a detached retina. Additionally, IOLs are contraindicated in infants less than 1 year of age because of the extreme propen­sity for these eyes to develop dense fibrotic membranes.

The most common postoperative complications were those associated with the surgery performed during the earlier years ofiOL implantation such as delayed capsulotomies of secondary membranes in the iris-supported series. This was a standard pro­cedure employed before the onset of routine posterior capsulectomy anterior vitrectomy lens extraction techniques. Corneal oedema occurred more fre­quently in these early patients for the aetiology was unknown that disruption of the corneal endothelial cells led to corneal decompensation and oedema. Dis­located IOLs also occurred more frequently in the iris-supported IOL series. Combined with pseudo­phakodenesis, which induced additional iris trauma and endothelial cell loss, this IOL type was aban­doned. Anterior and posterior chamber IOLs, the IOL styles of choice during the 1980s, have produced con­siderably fewer complications. However, the develop­ment of secondary membranes associated with posterior chamber IOLs still remains a serious disadvantage to their use in young children. Opacifi­cation of the lens capsule is an almost uniform occur­rence, for the IOL itself acts as the matrix for prolifer­ation of lens capsular epithelial cells to migrate across the posterior capsulectomy aperture and re­opacify it. Discissions of secondary membranes in these patients are complicated by the possibility for dislocation of the IOL with damage to either the iris, corneal endothelium or both. Technically easier, Nd:YAG laser capsulotomies are preferred for children 6 years and older or in those younger

282

children who are able to co-operate with this pro­cedure.

The incidence of secondary surgeries markedly decreases when the selection ofiOL type is carefully undertaken. The anterior chamber lens affords the least incidence of complications since lens elements and anterior vitreous have been removed and the IOL does not occlude the pupil.

Five iris-supported IOLs were explanted for recur­rent dislocations or for producing corneal oedema. Two explanted patients received anterior chamber IOLs to promote an enhanced visual result. The other three patients opted for no correction.

Final aphakic visual results achieved by children with traumatic cataracts are profoundly influenced by many interrelated factors and these include the age of the child at the time of the injury, the rapidity oflens opacification and development of the cataract, the time interval between the injury and lens extrac­tion, the extent of injury to other portions of the eye and visual system, the lens extraction technique and the complications generated by this surgery, the patient's ability to wear an externally applied aphakic optical device successfully, be it a contact lens or an epikeratoplasty graft, and the develop­ment and depth of deprivation amblyopia and the success of amblyopia therapy. Additionally, asso­ciated ocular injuries must be considered when the final visual results are tabulated. The vision achieved by these patients in this series is compar­able to that achieved in other series of patients following treatment for traumatic cataracts [1-46].

Additionally, comparison of the visual results achieved with the different modalities of aphakic rehabilitation used within our series, as well as to the results reported by others, reveals similar rates of success for IOLs, contact lenses, and epikeratoplasty. Direct comparisons are impossible due to patient selection and the presence of any confounding vari­ables in each patient population.

Comparison of the visual results achieved by those patients receiving a primary IOL implantation vs. a secondary implantation reveals that those patients rehabilitated with a primary IOL achieved better visual results than those patients receiving second­ary IOLs. This decrease in the success rate for second­ary implants is due to the fact that most of these patients had undergone a trial of contact lens rehabi­litation, failed and had a significant time lapse with the development of amblyopia before the secondary IOL implantation. An assessment of probable contact lens intolerance or a determination of the feasibility of contact lens use must be made in young children to avoid undue loss of time with the development of dense amblyopia prior to converting to an IOL.

Amblyopia remains a constant threat to visual

D.A. Hiles, K.P. Cheng, A.W. Biglan

success in children less than 8 years of age and pro­longed, dedicated occlusion therapy is an absolute necessity to preserve the normal vision that had been present before the ocular accident. The preservation of excellent vision is certainly possible in the major­ity of patients with traumatic cataracts and this fact has encouraged us to operate earlier, apply more innovative aphakic optical rehabilitative modalities and occlude the normal fellow eye with greater force­fulness in an effort to achieve an aphakic visual result for the injured eye as close to normal as possible.

REFERENCES

1 F. Juler. Amblyopia from disuse; visual acuity after traumatic cataract in children. Trans. Ophthalmol. Soc. UK., 41, 129 (1929).

2 P. Broendstrup. Amblyopia exanopsia in infantile cataract. Acta Ophthalmol., 22, 52 (1944).

3 A.J. McKinna. Results of treatment of traumatic cataract in children. Am. J. Ophthalmol., 52, 43 (1961).

4 C.D. Binkhorst and M.H. Gobin. Pseudophakoi after lens injury in children. Ophthalmologica, 154, 81 (1967).

5 C.D. Binkhorst, M.H. Gobin and P.A.M. Leonard. Post-trau­matic artificial lens implants (pseudophakoil in children. Br. J. Ophthalmol., 53, 518 (1969).

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