Cataract Surgery and IOL Implantation in Children

Aim

In search of better technique for management of childhood cataract a comparative study comprising lensectomy, ECCE and scleral tunnel surgery was undertaken. The objectives are to evaluate the techniques of, visual outcome and complications of cataract extraction with or without posterior chamber intra ocular lens implantation in children.

Introduction

The treatment of childhood cataract,congenital or developmental cataract is a perpetual problem that challenges the ophthalmologists throughout the world. Early management of these cases not only restores vision but also prevents further complications like nystagmus, strabismus or amblyopia. Clearance of lenticular opacity and correction of gross refractive error in these patients is an emergency, because lack of timely intervention leads to severe amblyopia. The majority of ophthalmologists in USA, both cataract surgeons and paediatric ophthalmologists favour implantation of intraocular lenses in children down to age two. Many are now advocating the indications below 2. How ever, there is a definite growing acceptance of the role of intraocular lenses in children because of recent development of continuous circular capsulorhexis, placement of intraocular lenses in the bag and posterior capsulorhexis with or without anterior vitrectomy. Anterior vitrectomy seems to eliminate the risk of developing a secondary cataract which is a post operative complication of great concern.

The purpose of this study was to evaluate the better technique, compare the different techniques for, result of, cataract extraction and primary posterior chamber lens implantation in children.

Materials and Methods

The study was conducted in the department of Ophthalmology, Rajah Muthiah Medical College Hospital, Annamalai University between 1994-2000. We studied a consecutive series of 30 eyes in 24 children attending to ophthalmology OPC of RMMCH, out of which 10 eyes underwent Transparsplana lensectomy(TPPL), 10 ECCE and IOL implantation and in rest 10, Scleral Tunnel Cataract Surgery and IOL Implantations were performed. Twenty five ( 83.33%) eyes had developmental or congenital cataract and 5 ( 16.66%) had traumatic cataracts. A cataract that is present at birth is considered congenital cataract and one that appears at later date is considered developmental. The children ranged in age from 2 yrs to 14 yrs at the time of surgery. The follow up period ranged from 6 months to 7 yrs. Informed consent was obtained from the parents of each child. They were given information on the risks, benefits and alternatives to the procedure. The contraindication to intraocular lens implantation included age younger than 1 year, chronic uveitis, glaucoma,microphthalmos with corneal diameter less than 9 mm,dislocated lenses and cases assigned for TPPL. In bilateral cases the most severely affected eye was operated on first and the fellow eye after 2-3 months.

In most of the cases, keratometry readings, A scan biometry and comprehensive ophthalmic examinations were performed before surgery. In young and uncooperative children where even visual acuity could not be assessed, fixation pattern or loss of central red reflex was considered an indication of surgery and a standard +20.5 D IOL was implanted.

Mydriatics of the operated on eye was achieved with 1% Tropicamide and 10% phenylephrine. All the surgeries were performed under general anaesthesia by a single surgeon who is well experienced with both TPPL and Tunnel Cataract Surgery. The eye was prepared for surgery in standard fashion.

Lensectomy

Two small conjunctival flaps created. Sclerostomy was done with MVR blade,2.5mm from the limbus,one for infusion canula and other for lensectomy cutter. With the same MVR blade the posterior capsule was cut and lens matter was mobilized. The lensectomy cutter (Storz) was introduced, the entire lens was removed along with a portion of anterior vitreous. The infusion was maintained with Ringer’s solution. The wound was closed with 10/0 nylon suture. Injection cefazoline 100mg and dexamethasone 2mg was injected s/c into the upper fornix. Over the years this was a superior surgical procedure to other conventional surgeries as there was no chance of leaving behind residual lens matter. One can achieve nearly complete removal of lens much easily with the help of automated vitrector so after cataract is almost nil, there is no damage to cornea, early ambulation is possible and overall post operative visual outcome is better.

ECCE

Following a small conjunctival flap, a 3mm limbal incision was given, entry to A/C was made. A/C was reformed with viscoelastic. A 26G needle cystitome was introduced, a rhexis or can opener capsulotomy was performed. Ringer’s lactate solution was used as intraocular irrigating solution, lens matter was removed with simcoe I/A canula. IOL was implanted either in the bag or in the sulcus after extending the incision. The wound was closed with 10/0 nylon suture. Injection cefazoline 100mg and dexamethasone 2 mg was injected s/c into the upper fornix.

Scleral Tunnel Surgery

A 6 mm wide frown scleral tunnel incision was given with a B.P. blade no.15, 2 mm posterior to corneoscleral junction, the two ends were around 4 mm behind limbus. The tunnel was dissected anteriorly to the vascular arcade with the help of Sharpedge angled tunnel blade no.4805 or by lamellar miniature blade no.6600.the anterior chamber was entered with a 3.2 mm Sharpedge angled keratome no.5540/5520,then the chamber was reformed with viscoelastic substance. A 5-6 mm diameter continuous curvilinear capsulorhexis was prepared. The capsule was initially opened with 26 G bent needle cystitome to create a small capsular flap. This flap was grasped with Masket capsulorhexis forceps and capsule was torn in a continuous curvilinear manner to complete the anterior capsulotomy. In few cases where rhexis was not possible anterior capsulotomy was done using 26 G bent needle. In no case a side port entry was made. Ringer’s lactate was used as the intraocular irrigating solution. To this solution was added 0.5 ml of 1:1000 intravenous adrenaline without preservative to maintain intraoperative mydriasis. The lens cortex and nucleus were aspirated using I/A canula or expressed by viscoexpulsion. All residual cortical matter near the equator of the lens or over the posterior capsule was meticulously removed. The capsule and anterior chamber were filled with viscoelastic substance. The inner entry was extended with the help of same keratome. The posterior chamber intraocular lens was implanted under direct visualization, the optic and both haptics were placed into the capsule. However, 3 cases it was implanted in the sulcus, where capsular bag was damaged. The IOL most commonly used were Appalens, Eye O Care and IMD lenses with a 6 mm optic and 12.5 to13mm overall diameter. The viscoelastic substance was removed with I/A. Subconjuctival injection cefazoline 50mg with dexamethasone 2 mg was given following which conjunctiva was closed with wet field diathermy.

In all the cases Prednisolone Acetate or Tobramycine- Dexamethasone eye drops and if required cyclopentolate 1% eye drops were applied postoperatively. The patients were examined daily during hospitalization for 3 days and were reviewed after 1 week, 2 weeks, 4 weeks, 3 months and then every 6 months. Postoperative refractions were performed at each visits and spectacles prescribed when the refraction was stable. If required, occlusion therapy of dominant eye for 75% to 90% of the child’s waking hours was instituted in patients younger than 9 yrs following one week of surgery.

Table 1 – Patient Demographics

Results

Out of 24 patients, 25 eyes had congenital or developmental cataracts, 5 were from accidental trauma out of which 2 eyes had penetrating injury (Fig 1), and 3 eyes had history of blunt injury.

In 2 eyes the posterior capsule was ruptured during cataract removal in the ECCE group, necessitating anterior vitrectomy and sulcus fixation of the posterior chamber lenses. Two patients had primary fibrosis of posterior capsule and plaques for which posterior rhexis was performed.

Table 2 – Visual Outcome

Ninety percentage of children achieved a binocular acuity of 6/60 or better. There is almost negligible difference in visual outcome between the three techniques at the 6 months follow up. Ten percentage of eyes had visual acuity less than 6/60. Although the lensectomy eyes required no secondary procedure than those had ECCE and scleral tunnel surgeries, the problem of aphakic spectacles in lensectomy eyes is a greatest barrier as well as cosmetically it is unappealing

Table 3 – Complications

In lensectomy and ECCE group, there was significant failure to remove all of the lens cortex, seen in 2cases and 3cases respectively. Iris trauma and loss of lens matter into the vitreous seen in 2 cases in both the groups. One should keep another machine stand by for machine failure in lensectomy, that was experienced in 2 cases. One lensectomy eye developed retinal detachment where as another case of tunnel surgery had preexisting retinal detachment. In one eye each,pupillary capture of lens developed in both ECCE and scleral tunnel group.IOL decentered in 2 eyes in ECCE group. After cataract noticed in 4 eyes of ECCE and 2 eyes of tunnel group,out of which one eye in each group was reoperated, surgical capsulotomy was done for dense after cataract. Aphakia in lensectomy group was routinely corrected with spectacles,bifocal spectacles were being used by 5 children.

Discussion

The main objective of this study was to find out

1. Which procedure is the safest and gives best long term visual outcome.
2. The frequency of operative, early and late post operative complications.

It is a fact that the conventional aphakic spectacles are useful in optical rehabilitation after bilateral congenital or developmental cataract surgery but not satisfactory for rehabilitation after unilateral or traumatic cataracts because of the problem of aniseikonia. Therefore it is a greatest barrier to good visual out come and cosmetically unappealing also. Unilateral or bilateral contact lens rehabilitation has the advantage of providing accurate and changeable optical correction. How ever, contact lens use in children requires significant co operation among parents, child and practioner. During last few years, the recent development of capsulorhexis and placement IOL in the bag has led to renewed interest for IOL implantation in children, but controversy still surrounds the question of how much hyperopia children should remain. Some ophthalmologists believe the child should made emmetropic or even myopic without concern for later myopic, they advocate curing the amblyopia and handling the myopia later. Some argue the opposite view points. What ever the fact, it is not always easy to calculate the IOL power in children. In that case one could implant standard +20.50D lenses.

The visual outcome of childhood cataract is dependent on many factors such as type of cataract, age of onset, age at surgery, duration of opacity and compliance with optical rehabilitation and occlusion. This trial was designed to determine the best and most suitable surgical treatment for childhood cataract at present time. Overall in 90% of eyes the visual acuity was achieved 6/60 or better. Although there is no much variation in the final visual out come in three different groups the complications are less encountered with scleral tunnel surgeries. In no time eye collapses, anterior chamber becomes flat or there is iris prolapse during this procedure. It is much easier, surgeon is comfortable through out the procedure. How ever, tunnel dissection is little difficult in children, as the sclera is little thin. One should avoid muscle relaxants during general anaesthesia and could master the technique in no time. Similarly rhexis is more difficult in children as it is not easy to tear anterior capsule, with experience it is not a problem at all. The key to it’s success is to start the rhexis more centrally ie.the capsule should be opened with a 26 G bent needle, the starting position should be more central to create a small capsular flap, then the flap is grasped with Masket capsulorhexis forceps and the capsule is torn in a continuous curvilinear manner avoiding radial extension.

Retinal detachment is well recognized and usually a late complication of cataract surgery in children. In this series there were two retinal detachments encountered, one in lensectomy group and other which was pre existing in the scleral tunnel group, which was due to high myopia. Conclusion. Management of childhood cataract poses many challenges to the ophthalmologists in the developing countries. Over the years there has constantly been search for a new technique, that more effectively manage paediatric cataract. Prior to CCC most IOLs were almost left partly or fully supported by ciliary sulcus. Since uveal tissue in a child is highly reactive, placement of IOL in the bag has been viewed, as highly desirable by most of the paediatric cataract surgeons. We recommend scleral tunnel cataract surgery, that is self sealing, sutureless and phacoless is the surgery of choice at present, for paediatric cataracts because of following reasons.

1. Anterior chamber never collapses during this procedure.
2. No nucleus present in childhood cataract, the problem of nucleus management which is most difficult in adults cataract surgery is very easy here.
3. Intra-operative complications are negligible, virtually there is no chance of expulsive haemorrhage.
4. Proper placement of IOL in the bag is easy (Fig 2).
5. The wound is more stable and secured, no side port entry is required.
6. It is relatively easy and repeatable without long and risky learning curve.
7. One can achieve faster and satisfactory visual rehabilitation, early ambulation possible (Fig 3).
8. It is inexpensive, very cost effective which is one of the criteria in all developing countries where most of the surgeons are unable to afford high tech equipments.

No doubt the paediatric surgeons now stand at the threshold of a new era filled with excitement, which greeted modern cataract surgeons few years back as they entered to sutureless cataract surgery with IOL implantation. Should we say now, good bye to ECCE and Lensectomy?

References

1. Kathryn M. Brady, C. Scott Atkinson, Laurra A Kitty, David A Hiles. Cataract surgery and lens implantation in children: Am J Ophthalmology 1995;120:1-9
2. Michael Eckstein, P Vijaylaxmi, Clare Gilbert, Allen Foster. Randomized clinical trial of lensectomy versus Lens aspiration and primary capsulotomy for children in bilateral cataract in south India: Br J Ophthalmology 1999;83:524-529
3. Surendra Basti,Mark J. Greenwald. Principle and paradigms of paediatric cataract management; Indian J Ophthalmology 1995;43:159-176
4. Michael Eckstein, P. Vijaylaxmi, Millind Killeder, Clare Gilbert, Allen Foster.Use of Intraocular lenses in children with Traumatic cataract in South India: Br J Ophthalmol 1998;82:911-915
5. Benjamin F Boyd. New Development in small Incision Manual Phacoframentation; Highlights of Ophthalmology 1999;6:5-12

For correspondence write to

Dr.P.Mishra ,
Professor of Ophthalmology,
R.M.M.CH.,Annamalai University-608002 India.
e-mail: [email protected]

http://www.indmedica.com/pictures/pic1.jpg (Figure 1)!

Figure 1

http://www.indmedica.com/pictures/pic2.jpg (Figure 2)!

Figure 2

http://www.indmedica.com/pictures/pic3.jpg (Figure 3)!

Figure 3

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