Ординатура / Офтальмология / Английские материалы / Master's Guide to Manual Small Incision Cataract Surgery (MSICS)_Garg_2009

Figure 28.1A: Conjunctival flap

Figure 28.1B: Wetfield cautery

5.A frown-shaped incision (Figure 28.2) is then given superiorly, about 1.5 mm away from limbus, and scleral tunnel (Figure 28.3) is constructed, using crescent blade.

6.Anterior chamber is then entered with 3.2 mm keartome and the internal opening is extended on both sides. Internal opening is kept slightly larger than external opening to facilitate easy nucleus delivery.

7.Hydrodissection is then carried out and nucleus is prolapsed in the anterior chamber.

8.With the help of irrigating vectis (Figure 28.4), the nucleus is helped out of the anterior chamber.

9.Irrigation and aspiration of cortical matter is done and a rigid posterior chamber intraocular lens (PCIOL) of appropriate power is implanted in the bag (Figure 28.5)

10.For trabeculectomy, the pupil is miosed with the help of intracameral pilocarpine and again anterior chamber is formed with viscoelastic.

Figure 28.2: Scleral incision

Figure 28.3: Creating a scleral tunnel

Figure 28.4: Nucleus delivery

Figure 28.5: Lens implantation

Figure 28.6: Trabeculectomy with Kelly’s punch

11.With the help of Kelley’s descemet’s membrane punch, the trabeculectomy is done by taking the piece of tissue from the lower lip of scleral tunnel (Figure 28.6). At least two to three punches are taken on the same site, so that a channel is formed for the aqueous to bypass the trabecular meshwork.

Peripheral iridectomy is done through the same opening.

12.The conjunctival flap is then sutured back with 8-0 vicryl. The intraocular pressure is then titrated by injecting balanced salt solution (BSS) through sideport incision and a bleb is thus raised.

We as a rule do not apply mitomycin C unless the pressure is too high (above 40 mm Hg), or it is a repeat trabeculectomy.

Next day, after opening the bandage, digital ocular massage is done to promote aqueous flow through the opening.

LIMITATIONS

1.The procedure is best if the intraocular pressure is up to mid-30s. The efficacy reduces somewhat if pressures are above 40 mm Hg. Mitomycin C can be applied on scleral bed in such cases.

2.The pressure cannot be easily titrated as with releaseable sutures.

3.Postoperative hyphema occurs in about 4-5% cases, which resolves within a few days.

We have found this procedure not only gives the convenience of performing both the procedures from same opening but also is quite quick to perform and has the benefit of being sutureless thus keeping the induced astigmatism to minimum, promotes very early visual rehabilitation and the results are comparable to the conventional trabeculectomy.

BIBLIOGRAPHY

1.Graham E Trope (Ed). Glaucoma Surgery. Taylor and Francis Group 2005.

2.Lai JS, Lam DS. Trabeculectomy using a sutureless scleral tunnel technique: A preliminary study. J Glaucoma 1999; 8(3):188-92.

3.Yadollah Eslami, Ghasem Fakhraie Heidar Amini Reza Zarei Sasan Moghim, Mohammad Taher Rajabi, Reza Ghaffari. The results of trabeculectomy using a sutureless scleral tunnel technique: International Ophthalmology.

INTRODUCTION

Surgical management of pediatric cataracts has always been challenging. After Sceie‘s paper on ‘Aspiration of congenital and soft cataract‘, pediatric cataract surgery has evolved through various techniques including iridectomy, discission, linear extraction, curette evacuation, extracapsular extraction, intracapsular extraction, aspiration, etc. Until recently the preferred method of choice has been pars plana lensectomy with anterior vitrectomy, followed by postoperative correction of aphakia.

Today, the method of choice for pediatric cataract is small incision cataract surgery (SICS), with or without posterior chamber intraocular lens (PCIOL) implantation. Although the age at which an intraocular lens (IOL) is implanted as a primary procedure is yet to be decided, majorities of surgeons today implant an IOL for one-year age and above. Visual results are greatly dependent on the time of uni/bilaterality, initial presentation, the time of surgery and the methods of optical and visual rehabilitation. Newer surgical techniques have certainly made the rehabilitation easier and have contributed significantly for better results. Pediatric cataract disrupts the development of the visual pathways and its surgical correction, in a way, is a part of overall management of amblyopia. I implant a PC IOL at all ages, the youngest I have implanted is a 20- day-old child with unilateral cataract.

WHY SICS AND IOL IN A CHILD?

Pars plana in a child is very small, and is almost nonexistent. Pars plana lensectomy surgery is associated with increased risk of retinal tears, as majority of the

time the entry will be through pars plicata or peripheral retina. Also, the posterior capsular support is removed irregularly and the posterior chamber IOL implantation either as a primary procedure or as a secondary procedure later becomes a difficult issue. Placing the IOL in the sulcus with retention of anterior capsule necessitates another limbal incision; moreover, the IOL centration is going to be difficult.

A direct limbal incision needs to be adequately sutured. Children being less manageable and difficult to follow up, suture-related problems, including infection, could be more prevalent. Also, limbal sutures for a direct incision need more frequent follow-ups, which obviously needs anesthesia. A direct incision, as against a tunnel incision, results in an unstable cornea, with perpetual alterations in the corneal astigmatism, initially with the rule, and ending up with a large against the rule in the later stages of life.

Amblyopia, even in a child with surgically wellmanaged cataract, is not a rare entity. Uncorrected aphakia is as good a stimulus to amblyopia as the cataract itself! Visual rehabilitation has to be meticulous. The role of an early IOL needs to be re-emphasized.

Fitting and maintenance of aphakik contact lenses in children is difficult, they get decentred or lost. Allergy and infections are common. Parents may loose compliance leading to uncorrected aphakia and amblyopia.

SURGICAL PROCEDURE

The child’s eye is not a miniaturized adult eye. Operating on it is a totally different plan altogether. Not only the spaces are smaller and the texture and feel of tissues different, the way tissues respond to surgical trauma is

also different. Do not be surprised by a vehement postoperative inflammation, which now is much lesser with the introduction of vitrectomy as part of the procedure. Why so, no body seems to know!

The right time for cataract surgery in a dense unilateral congenital cataract is from birth to 6 weeks of age (Birch and Stager).1 The chances for good visual acuity, better than 6/24, is lesser after this age. In bilateral dense congenital cataracts, permanent sensory nystagmus occurs if surgery is delayed beyond 3 to 4 months of age. In partial cataracts and acquired cataracts after infancy, several issues need to be considered about the timing of surgery. When a child presents after infancy with dense central cataract, surgery needs to be done at the earliest, within weeks. Partial cataracts can be managed with trial patching, if the level of visual loss is proportionate to the density and size of cataract. Mydriasis may be helpful. Surgery in partial cataract is indicated when the cataract reduces the visual acuity to 6/18. However, individual judgments are needed.

SURGERY

The complications like secondary cataract, glaucoma, corneal decompensation, IOL decentrations, deprivation, amblyopia, etc. were so high in the past that cataract surgery in a child by and large was disappointing. The advent of vitrectomy in mid-1970s revolutionized pediatric cataract surgery. In 1976, Parks et al introduced removal of central posterior capsule and anterior vitreous during the cataract procedure.2,3 The second major revolution is the introduction of the IOLs. Although Choyce implanted an IOL in the eye of a child with traumatic cataract as early as 1956,4 IOL did not become a routine in a child until the 1990s.5 Currently, IOLs are widely used for children beyond one year of age. Studies in unilateral congenital cataracts indicate that IOL implanted in the first 6 months of life may produce better visual acuity, but there is a higher risk of complications.6

Many adult cataract surgery techniques, such as clear corneal incisions, hydrodissection, foldable IOLs, and manual curvilinear anterior and posterior capsulorrhexis, can be adapted in older children. But younger children need special techniques.

ANESTHESIA

Once you have decided to operate, the child is taken under general anesthesia (GA). Surgery under Ketamine is not recommended. Ensure that the pupil is well dilated. A small piece of cotton soaked with topical

mydriatics, kept in the lower fornix, would quickly dilate the pupil even after the induction. A bridle suture for the superior rectus is avoided for the fear of postoperative vertical phorias and tropias. Intraoperative Bell’s phenomenon in lighter plane anesthesia is avoided by supplementing with topical anesthesia. Just before the surgery, keep a small piece of sterile cotton soaked in Xylocaine 2% on the proposed area of surgery for few minutes, although the surgery is done under GA. This reduces the sensory pain inputs to the central nervous system (CNS), and so minimizes the need for a deeper plane anesthesia as well as the total dose of muscle relaxants. The topical anesthesia reduces the reflex contraction of superior rectus during the surgery, and the extra-ocular muscles remain relaxed, thus reducing the vitreous upthrust. The keratometry and biometry are performed prior to surgery under GA, if they are not done earlier and then a library of IOLs are to be kept ready. Valsalva maneuvers and coughing are common during the recovery from GA, and hence secure suturing of wounds is important in children.

TUNNEL INCISIONS

Self-sealing tunnels of adult design although are universally used in children now, will often leak because of thinner and less rigid sclerocornea. Synthetic, absorbable 10-0 sutures, like Vicryl, are always used at the end of surgery to close all incisions, although they may appear secure and non-leaking. A sclerocorneal tunnel incision is generally opted in children with a superior or superotemporal approach. Place the incision so as to avoid perforating anterior scleral vessels. Temporal corneal incisions are avoided in children, as they are less secure, do not heal well and also they produce visible corneal scarring. The superior orbital margin as well as the Bell’s phenomenon protects the superior incision against injuries.

Avoid any stay suture on the muscle. A pull on the muscle, against its contraction, will induce postoperative vertical phorias/tropias. A fornix-based conjunctivaTenon’s flap is raised. To avoid separating the two layers, make the first nick 2 mm away and parallel to limbus, and dissect till you reach sclera. Pass one blade of the scissors between sclera and the dissected tissue, sweep down to the limbus and then cut the two layers from the limbus. About 5 to 7 mm wide conjunctival incision is adequate. Avoid the zone where there are perforating anterior ciliary vessels.

A sclerocorneal incision is ideal. A half thickness, frown or straight scleral incision measuring 4.5 mm or 6.5 mm (depending on the IOL chosen) is made 2 mm

behind the superotemporal limbus. Take the dissection into the cornea, for about 1.5 mm, but at this time do not enter the AC. The dissection through the sclerocorneae may be tricky, as the sclera is thin and fibers are more elastic and compact. A double bevel, very sharp spoon blade is my instrument of choice. A Fleiringa ring is desirable as it provides an external skeleton for the less rigid sclera and minmizes the tendency for scleral collapse.

As there will be no nucleus in a child, the size of incision depends upon the IOL chosen. For a PMMA 6 mm optic IOL, a 6.5 mm scleral incision is made. For an atruamatic introduction of a foldable IOL through a 2.8 mm injector, you need a 4.4 mm long incision. A 2.8 mm diameter injector has a circumference of 8.8 mm and so would need a 4.4 mm slit to enter. Make the incision adequate, and never squeeze a larger object through a tight tunnel. You would tear scleral lamellae, and result in a leaking wound that ultimately would scarify badly. This is particularly important in children, as the scleral rigidity is lower.

VISCOELASTICS

A high viscosity cohesive viscoelastic is essential for pediatric cataract surgery to facilitate maintenance of anterior chamber stability, to counter the low scleral rigidity and increased vitreous upthrust. In special situations like with a compromised endothelium, it is helpful to use initially a low viscosity dispersive agent like HPMC followed by cohesive viscoelastic, like a soft shell. Cohesive viscoelastics are also needed for secondary IOL implantation in aphakic children, as it dilates the pupil and reduces the trauma of releasing posterior synechiae.

ANTERIOR CAPSULECTOMY

Continuous curvilinear capsulorhexis (CCC) is highly desirable in a child, to minimize extensive capsular fibrosis. It is also needed if there is an inadequate posterior capsular support, so as to resort to sulcus fixation. The anterior capsule is very elastic in child and poses great challenges. Perform an anterior capsulotomy with a 26 G cystitome, the tip of which is bent away from the bevel to 90 degrees. Mount it on a 2 ml syringe filled with air. Enter the AC with the cystitome, through the bed of the tunnel, at the limbus, not at the anterior end of the tunnel you have just created. Exchange the aqueous with air. This is done by slowly injecting air into AC and letting the aqueous escape through a 30 G needle, introduced obliquely at the left

limbus. Anterior capsule is highly elastic in children and so aim for a small CCC. Remember that the zonular fibers extend centrally to cover a very large area of the anterior capsule and resist a circular capsular tear, especially if the CCC is aimed to be big. As a closed chamber is essential, if air tends to escape, then fill the AC with a viscoelastic and complete the tear.

Manual CCC is difficult to perform. More force is required when pulling the capsular flap before tearing begins. Control of the capsulectomy and prevention of ‘runaway rhexis’ can be extremely difficult. In difficult cases, fill the AC with a high viscosity viscoelastic. This flattens and slackens the anterior capsule and assists easier tearing in a controlled fashion. If the capsule is very resistant to tear, use a Utrata forceps to complete the CCC, under viscoelastic. You need to enlarge the entry to introduce the Utratas. You can actually generate an enormous amount of traction with this forceps! Utrata’s capsulorhexis forceps performs better than a needle cystitome in these cases. Regrasp the capsulorhexis edge frequently. Begin with a capsulotomy smaller than desired. When tearing, force is directed towards the center of the pupil. The elasticity of the capsule makes the opening larger. Achieve about 5 mm diameter CCC. Ultimately, if the capsule begins to extend peripherally, stop before the edge runs away under the iris. Convert into one of the techniques described below. CCC is difficult in children. Vasavada and Chauhan failed to create an intact CCC using manual techniques in 80% of infants on whom this technique was attempted.7 Alternative methods are:

A vitrectomy probe can be used to create anterior capsulectomy. A venturi pump system works better than a peristaltic pump system. The vitrectomy probe is introduced into the closed eye through a tight tunnel stab incision made at the limbus with an MVR blade. Irrigation is through a Blumenthal infusion cannula through a tunnel stab incision at 6 0’ clock. With a cutting rate of about 300 cycles per minute and the port oriented posteriorly, the center of the anterior capsule is aspirated up into the cutting port to create an initial opening. Enlarge the capsular opening using the cutter in a circular fashion. Keep the cutter just in front of the capsular edge and aspirate the capsule into the port rather than working in the plane of the capsule and chopping it directly. Any lens matter that exits is aspirated simultaneously. This technique can be easily performed even in white cataracts. A smooth, round capsulectomy can be produced, which resists radial tearing. The more elastic the anterior capsule, the smoother the edge of the rhexis and works best in young

patients in whom the manual CCC is difficult. This technique is less ideal in older children because the capsule elasticity begins to approach than that of an adult capsule. The capsular edge appears more scalloped and tears easily.

A third option for creating an anterior capsulectomy in a child is through the use of radiofrequency (RF) diathermy. I use Ellman Surgitron unit in difficult situations of anterior capsulectomy, with its special hypodermic needle mount attachment. A high frequency, low energy current in its purest form is used, so as to optimize the cutting energy and minimize the heat. The steel cystitome is mounted on the hand piece and the tip is placed in contact with the anterior capsule, under viscoelastic. The footswitch is then activated and the capsulectomy size and shape are controlled as it is moved along a circular path. Gas bubbles are formed but do not usually interfere with visualization. The cut edge of the capsule rolls up slightly and a larger capsulectomy results than that is initially aimed at. Corneal endothelial cells are not damaged. RF diathermy capsulectomy edge is less elastic when compared to that of manual CCC. Kloti’s dedicated endodiathermy and Fugo blade can also be used for RF anterior capsulectomy.8

REMOVAL OF LENS MATTER

Now enlarge the cystitome entry at the base of the tunnel, at the level of limbus, with the MVR blade. Use a Simcoe cannula through this port to simultaneously irrigate balanced salt sodium (BSS) and aspirate cataractous lens. Hydrodissection and delineation can be attempted but a classical dissection of layers is difficult in a child. However, the hydroprocedures will loosen the lens matter, and assist in its aspiration. Instead of a continuous injection, small bursts of fluid injection at different levels and clock hours aid the cortical separation. The lens matter does not have the layered anatomy of an adult cataract. Neither it has the fibrous continuity, that if you engage one end of the lens matter into the port, the entire segment could be aspirated. The lens matter comes out in irregular clumps, like putty and has a gummy consistency. Complete cortical aspiration is mandatory to minimize postoperative inflammation even if a primary posterior capsulectomy is done. Pupil would tend to constrict, and this can be minimized with preoperative topical NSAIDS. Use a drop of preservative free Adrenaline in the irrigating fluid in difficult situations. Rarely, there could be mild inflammatory fibrinous exudation intraoperatively, and this can be minimized by adding

Inj. Heparin into the irrigating solution. An AC maintainer introduced at 6 o’ clock will be of use, as it keeps the AC deep and pressurized, and keeps the pupil dilated. Indeed, AC maintainer is of great help if used throughout the surgery. Phacoemulsification is not only useless to extract the lens but also as the anterior chamber is unstable, could be hazardous. However, the vitrectomy handpiece can be used with active suction. Bursts of cutting can be used intermittently to facilitate the aspiration of the resistant lens matter. Despite meticulous removal of equatorial lens epithelium, a Soemmering’s ring will form in most children.

PRIMARY IOL IMPLANTATION

The consensus is to implant an IOL in all children older than 2 years.9,10 The majority of axial growth occurs during the first 2 years of life.11 This makes selection of an IOL power for an infant difficult. Low scleral rigidity makes IOL implantation technically more challenging in infants. Despite these complexities, IOLs are being implanted in infants with increasing frequency.

IOL in children has to be implanted within the bag. Avoid fixating one haptic in the bag and the other in the sulcus, as it leads to IOL decentration. Dialing the IOL into the capsular bag is difficult in children. So implant it into the bag, in the first attempt itself. When it is needed to dial the IOL into the bag, you may need to do it bimanually, in a deep AC, under Viscoelastic. Acrylic and PMMA IOLs are preferred in children because of their proven track record. Recent studies have recommended the heparin surface modified variety of PMMA IOLs to reduce the incidence of posterior synechiae and lens deposits. While silicone IOLs are not recommended in children, the secondgeneration silicone material appears to be an acceptable alternative for older children.12 When capsular fixation is not possible, sulcus placement of both the haptics of an IOL in a child can be done. Rigid PMMA IOLs are preferred for sulcus fixation, as it minimizes the decentration.

For secondary IOL implantation, under the protection of a viscoelastic, meticulously dissect the synechiae between the iris and the residual capsule, all along the periphery. Many a time, a Soemmering’s ring keeps the anterior and posterior capsules separated. Reopen this peripheral capsular bag all round and aspirate the material. Insert the PMMA or Acrylic IOL within the peripheral capsular bag. If this is not possible, a heparin surface modified PMMA IOL is inserted into the sulcus. An optic capture is done posteriorly through the capsule, to ensure long-term centration.

When capsular support is inadequate, do not implant IOL unless the child cannot tolerate contact lenses or spectacles. In these very rare situations, consider Kelman quadriflex AC IOLs. Although their long-term safety is yet to be established, they seem to be well tolerated in children with normal anterior segments if properly implanted without iris tucks or mal-sizing. Transscleral fixation of posterior chamber IOL can be considered, but pupillary capture, suture erosion, lens tilt and displacements are seen more often in children.

MANAGEMENT OF POSTERIOR CAPSULE

As the incidence of PCO is 100% in pediatric cataract surgery, a posterior capsular CCC and anterior vitrectomy is mandatory, at least till the age of 5 years. This is done under a viscoelastic, in a deep AC, with a Utratas capsulectomy forceps. I do the initial central nick with a 23 G needle. I hold the edge of the nick with Utrata, and complete the CCC. The hyaloidal face is not disturbed at all. Again aim for a very small rhexis, smaller than the anterior rhexis. Aim for about 2 to 3 mm size, and it will end up larger. Now excise anterior hyaloid face and anterior vitreous with a vitrectomy probe. I prefer low aspiration and a cutting rate of 600, and the eye needs to be continuously infused during the procedure. A closed chamber vitrectomy is preferred and hence use the port at the base of the tunnel to enter the probe, and not the main tunnel itself. Working with the vitrector probe through the main tunnel also distorts the cornea, limiting the visibility.

The advent of primary posterior capsulorhexis and anterior vitrectomy in young children has dramatically improved the success rates and minimized the need for secondary surgery. Complications like retinal detachment and cystoid macular edema are reported to be exceedingly rare after pediatric cataract surgery with or without primary capsulectomy and vitrectomy. NdYAG Laser posterior capsulotomies are needed almost in every child if posterior capsulectomy is not primarily performed, and this also carries a greater risk of retinal detachment and cystoid macular edema. In addition, as pediatric capsules undergo intense fibrosis, larger amounts of laser energy are often needed as compared with adults, and the posterior capsule opening may close down, requiring repeated laser treatments or a secondary pars plana membranectomy.

Studies have shown that a posterior capsulectomy without a central vitrectomy would be unlikely to prevent the development of a secondary membrane.18

In fact, the opacification rate was not significantly decreased by a posterior capsulectomy alone. Only when an anterior vitrectomy was added did the opacification rate fall. In a prospective and randomized study, Vasavada and Trevidi19 showed that visual axis obscuration across the anterior vitreous face occurred in 70% of those eyes in which vitrectomy was not performed after posterior CCC in children 5 to 12 years of age. No eye developed visual axis obscuration when a posterior CCC was combined with an anterior vitrectomy. Once an anterior vitrectomy is performed, an IOL optic capture is no longer necessary.

SELECTION OF IOL POWER

The choice of IOL differs with the surgeon. I prefer a heparin-coated PMMA IOL of diameter 6 mm. The long C loops, which confirm to the shape of the capsular fornix are more desirable than the J-like loops of most of the IOLs. A foldable IOL of acrylic make can be chosen, but the enormous fibrotic capsular contraction forces would surely distort the IOL to some extent, resulting in higher order visual aberrations. As a large number of IOLs do decenter marginally, avoid IOLs smaller than 6 mm. IOL should have full 6 mm optic (many IOLs have an edge which is non-optical), be made of one piece and shall have no holes. Their mesopic pupil size is going to be bigger than in an adult eye and any of the anomalies in the peripheral lens optic will show up in the quality of vision in the night, when the pupil is dilated. Remember that the child has to go through decades of active life, and needs the bestdesigned IOL.

To introduce the IOL, the AC is entered with a microkeratome, at the anterior end of the tunnel that was previously made. It is either a 4 mm or a 6 mm opening, depending on the IOL chosen. The AC is filled with visoelastic and the IOL is inserted straight into the capsular bag. Care is taken that the lower haptic gets into the capsular bag and neither into the vitreous cavity through the PCCC nor into the ciliary sulcus. The rest of the IOL can be rotated into the bag using a Sinskey hook. If there is an AC maintainer, switch it of during this procedure. Reinject viscoelastic again and again to keep the AC deep. A dispersive viscous like methylcellulose is better at this stage than a cohesive viscoelastic, as the former protects the endothelium better and also maintains spaces adequately.

Selecting the IOL power in a child is challenging. Gordon and Donzis13 have documented the axial growth pattern in normal eyes, but controversy exists

about whether the pseudophakic eye grows predictably along the same curve. In the normal phakic child, there is little change in refraction (0.9 D from birth through adulthood on average) because the power of the natural lens decreases dramatically as the eye grows axially. We know that on atropinization, a child’s eye is often hypermetropic, the very strong accommodative effort makes the eye ‘emmetropic’. However, an IOL in a child’s eye do not change its power like this to match the growth of the eye. So, an IOL aiming emmetropia in early childhood would leave the patient highly myopic in older age.

Dahan et al14 reported that younger the child at the time of implantation, the greater the myopic shift over time. They suggested that a child under age of 1 year should receive 80% of the IOL power needed for emmetropia. Between 1 and 2 years, implant an IOL with 90% of the power needed for emmetropia. There would be initial hyperopia, which needs to be corrected with glasses immediately after the surgery, till they move on to emmetropia or slight myopia in adulthood.

Knight-Nanan et al15 suggested for less than 1 year of age, an IOL of power lesser by 6 D than emmetropic to compensate for the myopic shift. Awner et al17 suggested aiming for a postoperative refraction of 4 D for children younger than 2 years of age, 3 D for children 2 to 4 years of age, 2 D for children 4 to 6 years of age, 1 D for children 6 to 8 years of age, and emmetropia for children older than 8 years of age at the time of implantation. For children between 2 and 8 years of age, you can select an IOL power that will leave mild to moderate hyperopia, milder with increasing age.16 Some suggest aiming for emmetropia regardless of age when in children above 2 years of age. This approach aims at avoiding hyperopic amblyopia but is likely to result in significant myopia at a later date. To calculate the power of IOL, modern theoretical IOL formulae like Sanders- Retzlaff-Kraff (SRK) II, SRK-T, Holladay and Hoeffer Q formulae are preferred.

The viscoelastic has to be completely removed from the AC, from behind the IOL and from the capsular bag. Gently flush the back of the cornea to remove its coating that is stuck to it. Most of the eyes need a suture or two to close the tunnel. 10-0 vicryl could be used so that the child does not need to be taken into OR for suture removal. If an AC maintainer is used, one stitch would be needed to close the port. Bury the knots so that they do not irritate and the child can open the eyes and use it instantaneously.

Phacoemulsification has no role in a pediatric eye. The ultrasound energy is bad for the child’s eye;

moreover, there is no hardness in a child’s cataract to emulsify.

POSTOPERATIVE MEDICATIONS

A drop of Povidone-iodine 5% is instilled and antibiotic, steroid and atropine ointments are placed in the eye. The eyes are patched and a shield applied for one day. Topical atropine (0.5% in children younger than 1 year of age, and 1% thereafter) is instilled once per day for 2 to 4 weeks. Prednisolone acetate is used topically, and the frequency is titrated according to the clinical picture. Generally 3 hourly medication is advised for 2 weeks during the day and then three times per day for an additional 2 to 6 weeks. An antibiotic drop is used for 1 week. Residual hyperopia is corrected for NEAR after 1 week. Separate glasses for near and distance are given in school-going age. Postoperatively, the child needs very frequent topical steroids. Short-acting cycloplegics may be of use for a few days, to reduce the inflammatory response. If there is a hyperinflammatory reaction, children are prone for this, increase the topical steroids and a short-term systemic steroid regimen can be considered in consultation with the pediatrician.

In bilateral cataracts, I perform simultaneous bilateral surgeries. Intraoperatively, the two eyes are totally isolated, and operation theater procedures are as though they are performed on two different individuals. The gowning, gloving, painting, draping, instruments, etc. are separate for the two eyes. No instruments cross over from one eye to the other. Simultaneous surgery prevents two GA inductions and also minimizes the risk of amblyopia in the second operated eye.

FOLLOW-UPS

The use of protective glasses during the day and a shield at night is recommended for at least 2 weeks postoperatively. The child is seen after every week for one month and later at 3 months and 6 months postoperatively. The follow-ups later are based on amblyopia management. Yearly examinations under GA is essential in order to monitor intraocular pressure, peripheral retina, retinoscopy, A scan ultrasound, assessment of anterior segment and the IOL, and detect any PCO. Monitor any other ocular or systemic abnormalities. Aphakic or pseudophakic glaucoma is an important concern if the eye is microphthalmic. An unexpected myopic shift is an indication of glaucoma in a child. Amblyopia treatment is paramount during the follow-ups.

DO’S AND DON’TS

The surgical management of cataracts in children is challenging. Decreased scleral rigidity and increased vitreous upthrust make it more difficult. The anterior chamber is unstable, the capsular management needs caution and the eye is likely to react with severe postoperative inflammation. Selection of an IOL power is tricky. Compliance with postoperative instructions is difficult for the parents. The long expected life spans of children make the issues more challenging. These special patients are uniquely challenging. The child deserves best surgical techniques for optimal rehabilitation. Visual results are very satisfactory. Prescribe glasses to correct for the near vision initially, and later, in the school age, correct the left over hypermetropia for both near and distance. You may need to modify the spectacle powers once in 6 months. Squint and amblyopia, if any, needs to be addressed meticulously. Clear corneae, briskly reacting pupils, clear media, absence of inflammatory sequelae, absence of synechiae, well-centred IOL, and a smiling face and what more you want!

REFERENCES

1.Birch EE, Stager DR. The critical period for surgical treatment of dense, congenital, unilateral cataracts. Invest Ophthalmol Vis Sci 1996;37:1532-8.

2.Parks MM. Posterior lens capsulectomy during primary cataract surgery in children. Ophthalmology 1983;90: 344-5.

3.Taylor D. Choice of surgical technique in the management of congenital cataract. In: Vasavada AR, Trivedi RH, Singh R (Eds). Trans Ophthalmol Soc UK. 1981;101: 114-117.

4.Choyce DP. Correction of uniocular aphakia by means of anterior chamber acrylic implants. Trans Ophthalmol Society UK 1958;78:459-70.

5.Wilson ME. Intraocular lens implantation: Has it become the standard of care for children? Ophthalmology 1996;103:1719-20.

6.Lambert SR, Buckley EG, Plager DA, Medow NB, Wilson ME. Unilateral intraocular lens implantation during the first six months of life. J AAPOS 1999;3:344- 9.

7.Vasavada A, Chauhan H. Intraocular lens implantation in infants with congenital cataracts. J Cataract Refract Surg 1994;20:592-8..

8.Fugo RJ, Coccio D, McGrann D, Becht L, DelCampo D. The Fugo Blade: the next step after capsulorhexis. Presented at the American Society of Cataract and Refractive Surgery Symposium on Cataract, IOL and Refractive Surgery, Congress on Ophthalmic Practice Management, Boston, Massachusetts, May 23, 2001.

9.Taylor D. The Doyne lecture: Congenital cataract: The history, the nature, and the practice. Eye 1998;12:9-36.

10.Lambert SR, Drack AV. Infantile cataracts. Surv Ophthalmol 1996;40:427-58.

11.Gordon RA, Donzis PB. Refractive development of the human eye. Arch Ophthalmol 1985;103:785-9.

12.Pavlovic S, Jacobi FK, Graef M, Jacobi KW. Silicone intraocular lens implantation in children: Preliminary results. J Cataract and Refract Surg 2000;26:88-95.

13.Gordon RA, Donzis PB. Refractive development of the human eye. Arch Ophthalmol 1985;103:785-9.

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INTRODUCTION

Fry is a credited with the phaco sandwich technique. This technique is simple, allows removal of lens through a sutureless 6.0 to 6.5 mm self-sealing scleral tunnel incision and produces much less astigmatism compared to extra-capsular cataract surgery. The author has adopted this technique for over 5 years and results have been gratifying.

INSTRUMENTATION

Essentially the instruments required are similar to what an ECCE surgeon requires. Additional instruments are.

•Crescent knife

•3.2 mm angled keratome

•5.2 mm keratome

•Irrigating vectis

•Sinskey type dialer, iris repositor.

PREOPERATIVE PREPARATION

The essential thing in this surgery is wide dilatation of pupil, which allows easy prolapse of the nucleus in anterior chamber, prevents iris entrapment during delivery of nucleus. Pupil dilatation and its maintenance in dilated status is achieved by instilling tropicamide and phenylephrine combination + flurbiprofen eye drops. These are instilled 1 hour before the surgery. Author suggests a conventional ECCE if the pupil is less than 5 mm in diameter, at least in initial 50 cases. Acetazolamide one tablet is given 2 hours prior to surgery.

Anesthesia

A peribulbar anesthesia with a cocktail of 3 ml of Xylocaine with adrenaline and 3 ml sensorcaine mixed

with hylase is used. Superpinky ball or ocular massage for long is not recommended as it produces hypotony.

SURGICAL TECHNIQUE

Wound Construction

After applying speculum and holding superior rectus a fornix based conjunctival flap is fashioned. Bipolar cautery should be carried out carefully. It gives a bloodless field to operate and there is no inadvertent bleeding during the making of scleral tunnel, but its excessive use should be avoided as it causes postoperative astigmatism. 6 to 6.5 mm partial thickness scleral tunnel incision is made 1.5 mm behind limbus (Figure 30.1). Harder the nucleus longer is the incision. In initial 25 patients longer incision is recommended to avoid nucleus touch to the corneal endothelium. The scleral pocket is made with crescent knife (Figure 30.2).

Figure 30.1: Scleral tunnel being made