Clinical Outcome of Intracameral Dexamethasone in Paediatric Cataract Surgery in a Nigerian Missionary Hospital

Paediatric cataract surgery is associated with several complications among which is high ocular inflammatory response. Conventionally immediate post-operative subconjunctival steroid with adjuvant systemic and frequent topical steroids have been used to control post-operative inflammation. Studies have reported the advantage of intracameral dexamethasone in decreasing postoperative inflammation. Aim: To evaluate the clinical outcome of intracameral dexamethasone in paediatric cataract surgery in Evangelical Church of West Africa (ECWA) Eye Hospital, Kano. Method: This was a prospective study of 694 paediatric cataract surgeries from January 2006 to December 2014. All the patients were given intracameral dexamethasone 0.4 mg (0.1 ml) immediately after surgery. Each patient had surgical intervention on one eye. Evaluation was done on first, third postoperative day, one week and four weeks later (follow up visits). Outcomes were measured on the fourth week post-operation. Examination of children was done with help of slit lamp for cells, flare or any other sign of inflammation. In case of non-cooperative children examination was done with microscope under sedation/general anaesthesia for fibrinous reaction, exudative membrane, posterior synechiae and red reflex. Results: There were total of 694 patients with age range of 0 to 11 years. Mean age of participants was 2.03 ± 2.5 years. The mean duration of cataract before presentation to the hospital was 5.7 ± 4.3 months with a range of 0 to 16 months. Post operative complications, likely to be associated with intracameral dexamethasone were corneal opacity (0.6%) and raised intraocular pressure (12.5%). In 31 patients (4.5%) there was no post operative complication. Conclusion: Intracameral injection of dexamethasone has a role in preventing immediate postoperative anterior uveitis in paediatric cataract but may not be without complication.


Introduction
Cataract blindness is the leading cause of preventable blindness world-wide. It has been estimated that cataract accounted for 47.8% of the 37 million people who were blind worldwide in 2002 [1]. In Nigeria, 75 million are estimated to be children under 15 years, out of which 75,000 (1%) are blind from various causes, the leading cause of which is cataract [2] [3]. The main treatment option for cataract is surgery. Cataract surgery is one of the most commonly performed intraocular surgeries in paediatric ophthalmology. In our environment, cataract surgery by phacoemulsification is available in few centres. Although successful, paediatric cataract surgeries are often attended with post operative complications such as uveitis, glaucoma, posterior capsule opacification, retinal detachment to mention but few. Post operative uveitis can lead to complications like peripheral anterior synechiae, posterior synechiae, exudative membrane and pupil block glaucoma, thus hampering good vision and prolonging rehabilitation period [4].
Conventional attempts to minimize or eliminate post operative inflammations especially uveitis include subconjunctival or sub-tenon's steroid injection and post operative topical and oral steroid therapy. However, topical and oral steroid treatment strategies may be limited and not so effective in the control of post operative inflammation due to non-compliance and also the patient may squeeze his eyes while instilling drops that reduce the contact time of medication in the cornea [4]. Jamil et al. noted that intracameral dexamethasone may be better option than the subconjunctival route of dexamethasone [5]. Subconjunctival injection can cause subconjunctival haemorrhage that can be distressing to the patient. The globe can be accidentally perforated during subconjunctival injection.
Subconjunctival injection can cause pain and it is more significant when doing surgery under topical anaesthesia [6]. These disadvantages of subconjunctival injections make intracameral route a better alternative ocular drug delivery route in cataract surgery.
Studies had reported the advantage of intracameral dexamethasone in decreasing postoperative inflammation [2] [3] [4] [7], thus enhancing better postoperative visual outcome and shorter rehabilitation [7]- [14]. Moreover, anterior segment inflammation in terms of posterior synechiae and cell deposits are considered to be minimal when intracameral steroid is used immediately after cataract surgery.
However, some observers have questioned the rational of using intracameral dexamethasone since recent developments in cataract surgical techniques and and easily managed with only topical steroid drops [11]. Therefore, intracameral injection of steroids in regular cases seems questionable when the side effect of intraocular pressure increase is considered in the long-term.
This study was designed to evaluate the clinical outcome of a single intracameral injection of dexamethasone immediately at the end of uncomplicated phacoemulsification cataract surgeries with intraocular lens implant surgery in children in our local set-up.

Materials and Methods
This was a prospective study of 694 uncomplicated phacoemulsification paedia-

Results
Mean age of participants was 2.03 ± 2.5 years with a range of 0 -14 years. The difference in the ages among participants in the various sexes was not statistically significant (p-value = 0.979).
The mean duration of cataract symptom among the participants before presentation to the hospital was 5.7 ± 4.3months with a range of 0 -16 months.
There was both clinical and statistical difference (p = 0.000) in the post intervention visual acuity in the study. Over 93% subjects had visual improvement, although this improvement in vision could not be attributable to the intracameral injection only but more to the phacoemulsification cataract surgery.
The increase in the intraocular pressure following the surgical intervention and the intracameral dexamethasone injection was statistically significant (p = 0.000). The difference in the pre-and post-operative slit lamp findings among the study population was not statistically significant (p = 0.072).

S. O. Abu et al. Open Journal of Ophthalmolog
Post operative complications in this study, likely to be associated with intracameral dexamethasone were corneal opacity (0.6%) and raised intraocular pressure (12.5%). In 31 patients (4.5%) there was no post operative complication.

Discussion
This study was conducted to evaluate the clinical outcome of intracameral dexamethasone injections in 694 uncomplicated phacoemulsification paediatric cataract surgeries with intraocular lens implant. In this study, 434 participants (62.5%) were males and 260 (37.5%) were females (Table 1). Six hundred and ninety-four eyes were operated (one eye in an individual). This was to minimize the risk of the unknown. It was observed that the average duration of cataract symptom before presentation to the hospital among the study participants was 5.7 ± 4.3 months (Table 2).
In this study, post operative complications likely to be attributed to intracameral 0.4% dexamethasone injection immediately after phacoemulsification cataract surgeries, were corneal opacity (0.6%), anterior synaechiae/fibrin formation (6.2%), uveitis (3.6%) raised intraocular pressure (12.5%). The use of intracameral dexamethasone injections to suppress post operative intraocular inflammation and thereby enhance visual recovery and shorten stay of patients in the hospital has been reported by several authors [9] [10] [13]. Iqbal et al. found that intracameral dexamethasone injection increased its efficacy by about 5% as compared to subconjunctival route [15]. However, many authors have also  [17].
In this study, it was observed that 87 patients representing 12.5% had raised IOP which was statistically significant (p = 0.000) ( Table 3) nimal [17]. However, in our study, anterior synaechiae and fibrin formation were noted in 43 (6.2%) of our patients while uveitis was observed in 25 (3.6%) of the patients (Table 4). These observed differences need further investigations as there are many factors that could give raise to these clinical phenomena (rise in IOP and intraocular inflammation) during and after intraocular surgery. In collaboration with our finding, Solaiman et al. in Egypt using 4mg preservative-free triamcinole intracameral injections in 42 eyes found that there was statistically significant higher postoperative inflammatory membrane formation in the control group as compared with his study group [14].  Intra and postoperative cataract surgical complications may not be exclusively attributable to the use of intracameral dexamethasone as there are many confounding factors ranging from surgeon's skill and expertise, instrumentations and even postoperative care. Inadvertent complications arising from endothelial touch during cataract surgery could give rise to corneal endothelial damage resulting in corneal opacity. Therefore, further investigations and comparative study design are needed to buttress or authenticate our findings. However, unlike our observation, in the work of Jamil et al. it was observed that the use of intracameral dexamethasone at the end of cataract surgery was safe for corneal endothelium [5].
This study is limited in scope as there was no control group to compare the clinical outcome of intracameral dexamethasone in paediatric cataract surgery.
Also the follow up period was short. This leaves room for further investigation.

Conclusion
Intracameral injection of 0.4 mg of dexamethasone at the end of uncomplicated phacoemulsification cataract surgery in children is effective in controlling postoperative ocular inflammation with insignificant minimal complication.