Intracameral Versus Sub-conjunctival Dexamethasone Injection for Postoperative Inflammation in Congenital Cataract Surgery

Material and Methods: All Pediatric patients less than 15 years of age and of both genders, undergoing cataract surgery in Holy Family Hospital, were included in the study using a random table. Using standardized sample size calculator and statistical assumption with 95% CI and 5% alpha error, the study sample was 95 cases in each group. Group A patients got intracameral injection of dexamethasone while Group B patients got subconjunctival injection of dexamethasone. The outcome measure was intraocular inflammation after cataract surgery. Examination was done within first three postoperative days for signs of anterior chamber inflammation. Standard slit lamp or hand held slit lamp was used for this purpose.

ataract is one of the leading causes of blindness worldwide. It accounts for nearly half (47.8%) of the total 17.7 million cases of blindness 1 . Pakistani population is also getting equally affected from cataract, with high prevalence 2 .
The partial or complete blindness is mainly affecting the elder population and reducing their quality of life by making them dependent on others and posing economic burden on communities and the country 2,3 . Nevertheless, cataract affects all age groups C Pak J Ophthalmol but comparatively it is less common in children. VISION 2020 the "Right to Sight" is the main initiative program to control the visual deterioration and ultimate lasting blindness among children of developing countries. 3 Lifelong impact of cataract in childhood is very large considering the potential lifespan of a child 4 .
Congenital Cataract is cloudiness of the crystalline lens of the eye, which is present at birth and is mostly bilateral, clinically present with decreased vision or white reflex. It is diagnosed on slit-lamp biomicroscopy of the anterior segment of the eye. It can present in any form like nuclear, lamellar, sutural, coronary, polar and membranous cataract. The most common presentation is the nuclear cataract 5 .
The treatment for visually significant cataract is surgical, a highly cost effective intervention, with excellent prognosis for sight restoration. Early management of congenital cataract prevents the child from developing amblyopia and ensures good visual outcome 6 .
Congenital cataract surgery can result in complications like posterior capsule opacification, glaucoma and retinal detachment 7 . Most common post operative complication in congenital cataract is inflammation 8 . Inflammation can lead to complications like peripheral anterior synechiae, posterior synechiae, exudative membrane and pupil block glaucoma, thus hampering good visual rehabilitation. The rationale of the study was to find a treatment option which would reduce the post-operative inflammation and prevent complications.
Intensive conventional topical steroid treatment is still main trusted mode of managing inflammation, along with other available options, like subconjunctival injection during surgery, collagen shield, intracameral injection and sustained release intraocular drug delivery system 9,10 .
There are various therapeutic options for inflammation with different levels of efficacy and safety. We planned a study with the purpose of comparing the role of intracameral injection with subconjunctival injection of dexamethasone in preventing immediate postoperative inflammation after congenital cataract extraction.

MATERIAL AND METHODS
A randomized controlled trial was conducted at the department of ophthalmology, Holy Family Hospital, Rawalpindi for a period of one year from June 2014 to May 2015. Using standardized sample size calculator and statistical assumption with 95% CI and 5% alpha error, the study sample was 95 cases in each group. It was hypothesized that Intracameral injection of 0.5 ml (2 mg) dexamethasone reduces immediate postoperative inflammation after surgery for congenital cataracts. A total of 190 children with cataract were enrolled (WHO calculator), using a random table, 95 cases each in intra-cameral injection and sub-conjunctival injection groups.
Children less than 15 years and of both genders were enrolled. Visually significant congenital cataract was determined by Snellen"s visual acuity of < 6/6 for verbal child and cataract size more than 3 mm in the area of visual axis, obscuring fundal glow for nonverbal child. Cases with no associated anterior or posterior segment pathology were selected. Patients with secondary cataract, prior ocular surgery and per operative complication e.g. posterior capsular rent, nucleus drop were excluded from the study.
All the children were operated for aspiration of the lens, primary posterior surgical capsulotomy and anterior vitrectomy. Children below age of two years were operated without intraocular lens implantation while above two years with intraocular lens implantation. In group A, patients were given intracameral dexamethasone injection 0.5 ml (2 mg) and 0.5 ml (20 mg) gentamycin injection in sub-conjunctival area. In group B, 0.5 ml (2 mg) dexamethasone and 0.5 ml (20 mg) gentamycin injection were given in the sub-conjunctival space at the end of surgery.
Examination was done within first three postoperative days, for signs of immediate anterior chamber inflammation, by standard slit lamp or hand held slit lamp. In case of non-cooperative children, examination was done with hand held slit lamp under sedation or general anesthesia for posterior synechiae. Postoperatively all patients were given topical dexamethasone suspension (1 drop after every 1 hour), tobramycin eye drops (one drop after every 2 hours), 1% cyclopentolate eye drops (one drop after every 8 hours) for one week.
The study outcome was measured in terms of efficacy of intracameral injection and subconjunctival injection of dexamethasone in the treatment of inflammation after surgery of congenital cataract.
The data was entered and analyzed in SPSS version 20.0. Continuous variable like age was presented as Mean and SD. The categorical variables like gender, inflammation (posterior synechiae) was analyzed as frequency and percentages and compared between the two groups using chi-square test, a pvalue of < 0.05 was taken as significant.

RESULTS
One hundred and ninety cases (95 in each group) fulfilling the inclusion/exclusion criteria were enrolled to intracameral injection or sub-conjunctival injection of dexamethasone to see their effect on postoperative inflammation in congenital cataracts.
Age distribution of the cases showed that majority of the cases were within 1-10 years of age. In group A there were 73.68% (n = 70) patients and in Group-B there were 78.95% (n = 75). The results of age distribution are shown in Table 1.
The gender distribution showed that there was nearly equal distribution among males and females. The results of gender distribution are shown in Figure  1.
Comparison of the Intracameral injection with sub-conjunctival injection of Dexamethasone in terms of frequency of posterior synechiae (inflammation) was recorded which showed that 4.21% (n = 4) in Group-A and 15.79% (n = 15) in Group-B had posterior synechiae while remaining 95.79% (n = 91) in Group-A and 84.21% (n = 80) in Group-B had no findings of the morbidity. This difference in the incidence of inflammation post operatively was found statistically significant between the two groups (pvalue, 0.007) ( Table 2).

DISCUSSION
Congenital cataract is an important reason of visual impairment among children, throughout the world and 5%-20% of blindness in children is because of congenital cataract 11,12 . All over the world 1.4 million children are blind and blindness in 190,000 children is because of cataract 13 . Congenital cataract presents either since birth or shortly after birth 14,15 . In Asia 1 million children are blind because of congenital cataracts 16 . The estimated prevalence of cataract among children is 3 in 10,000 live biths 17 .
Surgical option is the main management strategy in these conditions, which is successful, however, some side effects also worries the patients. Ocular inflammation is one such complaint. The perioperative use of anti-inflammatory therapy has well Pak J Ophthalmol established role in standard cataract surgery. The aim is to treat postoperative intraocular inflammation and enhance patient's comfort. Different anti-inflammatory agents are used according to the patient's need and surgeon"s preferences 18 .
In the present study posterior synechiae were recorded in 4.21% cases in Group-A and 15.79% in Group-B, and the difference was statistically significant (p-value, 0.007). Our findings regarding significantly greater success of intracameral dexamethasone are in accordance with many previous studies. A study by Iqbal and colleagues reported that dexamethasone when injected intracamerally increased its efficacy by about 5% as compared to subconjunctival route 19 . Ahmad et al who evaluated the role of subconjunctival and intracameral dexamethasone found that the later had better results and concluded that intracameral injection of dexamethasone was superior to sub-conjuctival injection of dexamethasone in preventing immediate postoperative anterior uveitis 20 . Another recent study evaluated the effect of intracameral dexamethasone on corneal endothelium, and concluded that the use of intracameral dexamethasone at the end of cataract surgery is safe for corneal endothelium 21 . The study by Zhang et al demonstrated that the average inflammation score was significantly lower in Dexamethasone group compared with the Indomethacin and Ciprofloxacin groups. Moreover, they also witnessed decreased intra-ocular pressure with Dexamethasone compared to other study interventions 22 .
Our findings are in agreement with the above body of evidence, which is justifying the hypothesis that "Intracameral injection of 0.5 ml (2 mg) dexamethasone reduces immediate postoperative inflammation after surgery for congenital cataracts", Intracameral injection may be used for better management of postoperative inflammation following congenital cataract extraction.
Limitation of the study was that it was a single center study, which was focused on early postoperative results. Further study needs to be done to evaluate long term results of this intervention at multiple centers.

Intracameral
injection of dexamethasone is significantly better than subconjunctival injection in terms of frequency of early postoperative inflammation in congenital cataracts. This leads to better visual rehabilitation.