Safety and Efficacy of ‘In Sulcus’ Placement of Soft Foldable IOL in Children

Safety and Efficacy of ‘In Sulcus’ Placement of Soft Foldable IOL in Children

Dr. Md. Nasimul Gani Chowdhury¹, Dr. Afrina Khanam²*, Dr. Farzana Akter Chowdhury³, Dr. Tasmin Akter⁴, Dr. Musharrat Alam Tarin⁵ 

¹Chief Consultant, Chittagong Eye Infirmary & Training Complex (CEITC), Chattogram, Bangladesh

²Resident, Institute of Community Ophthalmology (ICO), Chittagong Eye Infirmary & Training Complex campus, Chattogram, Bangladesh

³Consultant, Chittagong Eye Infirmary & Training Complex (CEITC), Chattogram, Bangladesh

^4,5Assistant Surgeon, Chittagong Eye Infirmary & Training Complex (CEITC), Chattogram, Bangladesh

^*Corresponding Author

DOI: https://dx.doi.org/10.47772/IJRISS.2024.8110265

Received: 16 November 2024; Accepted: 25 November 2024; Published: 24 December 2024

ABSTRACT

Purpose: To evaluate the safety and efficacy of ‘In Sulcus’ placement of soft foldable IOL in children with congenital cataract. Methods: 40 pseudophakic eyes of 20 children with bilateral congenital cataract were retrospectively reviewed. All the patients were planned for In Bag placement of IOL but due to surgical constraints In Sulcus placement of single piece IOL were done. The age range of patients was 1 to 3 years. All the patients were reviewed for at least upto 2 years with frequent intervals. Visual function, refractive status, anterior chamber depth, pupil reaction, IOL position, IOL capturing, IOP and fundus changes were assessed in different follow up. Results: No significant adverse effects were seen in visual function, refraction, anterior chamber depth, pupil reaction, IOL capturing, IOP and optic disc changes ‘In Sulcus’ placement of soft foldable IOL in children. Conclusion: Soft foldable IOL can be placed safely in sulcus in case of surgical constraint in children with congenital cataract.

Keywords: single piece IOL, soft foldable IOL, sulcus placement in children.

INTRODUCTION

Congenital cataract may be unilateral or bilateral and the majority of cases are treatable [1]. This cataract may be associated with microcornea, microphthalmos, thick anterior capsular calcification attached with posterior capsular calcification, posterior capsular dehiscence or hole. These critical associations pose challenging intra-operative difficulties for the surgeon and patients has to be kept aphakic. Aphakic management with high power convex lens is uncomfortable and creates spectacle intolerance. Furthermore, binocular function cannot be obtained. So, the ultimate surgical outcome ends with unwanted amblyopia.

The feasibility of IOL implantation in pediatric eyes has long been established [2]. The major advantage of an IOL is that it provides permanent continuous correction of aphakia, which is important in preventing amblyopia and fostering normal visual development in young children [3]. Placement of a posterior chamber IOL into the capsular bag is preferred as it results in a close-to-normal position. In some cases, due to surgical constraints, the IOL is inserted into the ciliary sulcus with the premise of sufficient support of the remaining lens capsule [4]. Ciliary sulcus fixation of IOL in pediatric eyes has been proven to be reasonably safe and effective over the short-term according to several studies [5],[6],[7],[8].

Regarding single-piece IOL implantation in the sulcus, there were contradictory findings. There are no conclusive reports of single piece IOL in sulcus implantation [5]. Despite this, single-piece IOL implantation in ciliary sulcus following posterior capsular rupture is gaining popularity [6]. This is partly due to lower availability of 3‑piece IOLs. Several studies have reported the safety and appropriate centration of single‑piece IOL in the sulcus [7],[9] that are inconsistent with the results of other studies [10].

Hence, the purpose of the study was to evaluate the safety and efficacy of soft foldable single piece IOL implantation In Sulcus in children with these critical associations creating surgical constraints.

METHODS

This retrospective observational study was conducted in 40 eyes of   20 children aged between 1 year to 3 years who were previously diagnosed as bilateral congenitalcataract and surgeries were performed in Chittagong Eye infirmary & training complex (CEITC), Chattogram between January 2019 to January 2022. Data were included on age at surgery, sex, preoperative axial length reading, intra-operative challenges i.e. membranous cataract, anterior capsular calcification, attached anterior and posterior capsular calcified opacification, posterior capsular dehiscence or hole, post-operative visual function, refraction, anterior chamber depth, pigment dispersion, iris bowing, pupil reaction, IOL position, IOL capturing, IOP and fundus changes. Unilateral and traumatic cataract, microcornea and follow up less than 2 years were excluded. All surgeries were performed under general anaesthesia by a single expert pediatric ophthalmologist.

The preoperative examination included visual assessment (CSM method), slit lamp biomicroscopy, direct and indirect ophthalmoscopy after full dilatation and B-scan ultrasonography. Intraocular lens (IOL) power calculations were done on the basis of axial length (Ocuscan machine) proposed by Dahan E and Drusedau MU [11]. In addition, 20% under correction were done for children less than 2 years and 10% under correction were done above 2 years.

With aseptic precaution all patients underwent cataract surgeries under general anesthesia with spontaneous ventilation. At 11 and 2 o’clock, corneal tunnels were created with an MVR blade. Pupil dilation was done by injecting adrenaline into the anterior chamber. The lens’s anterior capsule was stained with Trypan blue. Continuous curvilinear capsulorrhexis (CCC) was done by 25G ILM forceps (Alcon). An automated I/A hand piece with an Optikon R-Evo Smart machine was used for irrigation and aspiration (I/A) in every case. Each patient had planned the In Bag placement of soft foldable single piece IOL but due to surgical constraint In Sulcus placement were done. An automated vitrectomy machine was used for both the primary posterior capsulectomy (PPC) and the anterior vitrectomy (AVT). For sealing the corneal tunnels, 10-0 nylon was used. A subconjunctival injection of dexamethasone (2 mg) and gentamicine (5 mg) was administered to each patient. The eye remains covered until the 1^st post-operative assessment. Following surgery, all the patients were released after one day of surgery and re-evaluated after one week, one month and three months intervals. Antibiotics eye drops were used up to one month. Steroid eye drops were applied and gradually reduced over the following 8 weeks. Systemic steroids (1 mg/kg body weight) were given orally in tapering dose. All the sutures from cornea were removed after one and half months of surgery by total intravenous anesthesia with ketamine. During suture removal Intraocular pressure (IOP) were measured by Perkins tonometry. Refraction and spectacles prescription were given after one week. Post-operative visual assessment was done by CSM method & Cardiff acuity cards. Pupil reaction and IOL position were assessed in every follow up. Fundoscopy were done in every follow up visit after one month of surgery. Anterior chamber depth were assessed by Van Herrick method in each follow up visit.

Statistical analysis was done by using SPSS software version 16.0. Normality of data was estimated from P-value. A value of P <0.05 was defined as statistically significant.

RESULTS

40 pseudophakic eyes of 20 children underwent cataract surgeries under general anesthesia were included in this study. The age range was 1 year to 3 years. The average age was 24±4 months. The follow up range was 2 years to 4 years. 12 (60%) of the cases were male and 8 (40%) of the cases were female.

In Sulcus placement were done due to surgical constraints. These surgical constraints are large pre-existing posterior capsular hole in 23 eyes (57.5%), membranous cataract in 12 eyes (30%) and attached anterior and posterior capsular calcified opacification in 5 eyes (12.5%).

Table 1: Age distribution according to IOL placement

Repeated shallowing of the anterior chamber was the troublesome intra-operative challenges of the cataract surgery in soft foldable IOL implantation in sulcus placement in all cases. Suturing was done in every case even in side-port.

Post-operatively Anterior chamber depth was found normal assessed by Van Herrick method. Iris bowing & correctopia was seen in 4 eyes of 4 patients (10%).

Increased inflammation was seen in 18 eyes (45%) on 1st post-operative day and resolved by topical & systemic steroids. On the 1st post-operative day, corneal oedema was seen in 18 eyes (45%) due to eventful surgeries. 3 eyes of 3 patients (7.5%) developed thick membrane and membranectomies were done later on. No pupillary optic capture of IOL was recorded.

Visual assessment revealed central, steady, and maintained in 20% of cases and central, steady, and unmaintained in 60% of cases; Cardiff acuity cards revealed 6/60 to 6/24 vision in the remaining cases, with the average residual hypermetropia being +5.00D above 1 year and +4.00D above 2 years, which decreased to +4.00D and +3.00D after 1 year respectively.

Table 2: Post-operative complications

3 eyes of 3 cases (7.5%) showed increased IOP which was managed conservatively. In the rest of the cases IOP were within normal limit (11±3.35 mm of Hg). No significant optic disc changes were noticed except in 1 case which showed advanced cupping. Peripheral retina and vitreous were normal in all cases.

The most frequent cause of visual loss was amblyopia caused by stimulation deprivation. Amblyopia was more pronounced in the second fellow eye. This marked amblyopia in second eye was due to competitive inhibition because of delaying surgery.

DISCUSSION

Successful intraocular lens (IOL) placement in cataract surgery is synonymous with the IOL being placed in the capsular bag. When the capsular bag is violated, the ciliary sulcus becomes an option to approximate an in-the-bag position ^[12]. The ciliary sulcus is a suitable location due to its anatomic aspect for IOL implantation following capsular rupture ^[13]. The characteristics of a suitable IOL for sulcus implantation include large optics and thin haptics to reduce IOL decentration and improve the view of the retina in case of vitrectomy due to complications, and reduced scratching of the posterior iris surface, respectively. The iris alternation due to contact was influenced by several parameters including material, thickness and size of the IOL, implantation technique, and the haptics angle ^[14]. Complications may be reduced by monitoring these factors.

The currently recommended intraocular lenses to be placed in the sulcus are the three-piece intraocular lens or a single-piece PMMA rigid intraocular lens ^[15],[16]. This was primarily because three-piece IOLs and single-piece PMMA rigid IOLs are designed to be more stable in sulcus because of their large optic diameters and long haptics which are crucial to maintain stability in the sulcus. At the present time, designs of intraocular lenses continue to evolve, and the optic diameters and overall lengths of single-piece IOLs already approximate that of three-piece. Intraoperatively 3-piece IOL remain stable, but thin haptics of 3-piece IOL behaves like a wire. Its end may cause more iris irritation, recurrent iridocyclitis & hyphaema if not properly positioned. Although single piece IOL fluccuate intra-operatively, later on it becomes stable and due to its blunt and round end, there is no chance of iris irritation, iridocyclitis & hyphaema.

Single piece IOL in sulcus placement was discouraged in several studies ^{[15],[16],[17],[18]} due to its increased complications, like increased inflammation and IOP. This was because the old designed single piece IOL was undersized for ciliary sulcus placement, square edge optic, thick haptics and unpolished side walls. These are not happening now-a-days, because modern single piece IOL has got a large optic size of 6 mm diameter with no angulation which decreases the chance of iris irritation and iris chafing. Furthermore, due to its overall size of 13 mm, IOL decentration and IOL tilt are decreasing now-a-days. In addition, the modern single piece IOL has round edges and polished side walls which reduces the chance of pigment dispersion.

Postoperative IOP rise is a concern after IOL implantation in children. The exact mechanism of postoperative IOP rise after soft IOL implantation in children is still unknown. This may be due to surgical trauma during operative procedure, increased inflammation, pigment release, debris deposition and mechanical deformation of the trabecular meshwork ^[19],[20].

Another demand for any sulcus implanted IOLs is to keep its central and steady positioning as decentered IOL with its optic edge visible within the pupillary space may result in glare symptoms ^[21]. In our study IOL decentration with single piece IOL was not significant (2 eyes, 5%), so these sorts of complications were not noticed.

We noticed both corneal oedema and increased inflammation in 18 cases (45%), membrane formation in 10 cases (25%) in 1^st post-operative day. This was because these surgeries were eventful due to pre-existing posterior capsular hole and huge vitreous prolapse which prolonged duration of surgery. Iris bowing and correctopia were noticed in 4 eyes of 4 patients (10%). This correctopia was due to vitreous tag which could not be managed properly intra-operatively because of eventful cataract surgeries. Anterior vitrectomies were done in these cases under general anesthesia later on. We noticed no pigment dispersion and iris transillumination defect after surgery in the follow up period. In our study cup-disc ratio and neuro-retinal rim were found to be normal in all patients except in 1 case (2.5%) which showed advanced cupping. This was due to treatment incompliance post-operatively. Peripheral retina reveals no abnormalities.

Post-operative IOP rise is a major concern of IOL implantation in sulcus, which may cause watering, photophobia, blepharospasm, decrease corneal clarity, increase corneal diameter and optic disc changes. We faced challenges in 2 eyes of 2 patients with IOP rise which were managed conservatively. There were no pupillary optic captures of the IOL in our study. This was because we did not apply atropine eye drops after surgery. Instead, to keep the pupil mobile and reacting, we used a topical mixture of phenylephrine and tropicamide. In our series 3 eyes of 3 patients (7.5%) developed thick retrolental membrane formation causing obscuration of visual axis. Later, membranectomies were done again under general anaesthesia.

Bar-Sela and Fleissig. ^[22] concluded in their study on sulcus implantation of single-piece acrylic IOL designed for both in-the-bag and sulcus positioning that a properly constructed single-piece acrylic IOL may be placed in the ciliary sulcus during phacoemulsification with PCT ^[23]. There is no debate in current available literature regarding the visual outcomes of implanting a single-piece IOL in the sulcus ^[6],[12]. Visual acuity remained excellent for those with stable sulcus IOLs because it maintained the advantages of a small incision surgery with good postoperative visual results ^[7]. Additionally, the near proximity of the sulcus with the bag provides a good option when the posterior capsule gets compromised ^{[5],[15],[16]}. Similar papers showed a good visual outcome for majority of eyes implanted with sulcus single-piece IOL with at least 20/40 or better in all eyes ^{[5],[10],[18]}. The cumulative incidences of postoperative inflammation between single-piece and three-piece IOLs showed no sufficient evidence to conclude that there is a significant difference between the two groups ^[12].

The limitations of our study were relatively small number of patients, infrequent IOP measurement and short follow up period. Further studies with long term follow-up with adequate number of patients with detailed ultrasound biomicroscopic analysis (UBM) of anterior segment are recommended.

Well-functioning machinery support is prerequisite to utilize surgical expertise in these challenging issues of pediatric cataract surgery.

Conflict of interest: None.

Financial support: None.

ACKNOWLEDGMENTS

Ahmedur Rahman Research Center of Chittagong Eye Infirmary and Training Complex.

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