Dr. Kirandeep Kaur, Dr. Manas Nath, Dr. Sahil Bhandari, Dr.Prasanth Geerish
INTRODUCTION
Ocular trauma is one of the leading causes of monocular visual disability and blindness worldwide (1,2) and with the introduction of Birmingham Eye Trauma Terminology (BETT) classification and Ocular Trauma Score (OTS), the documentation of has been standardized.(3)The incidence of ocular trauma varies in different parts of the world. Krishnamachary et al reported approximately 1.6 million people in the world have become blind as a result of ocular injury with 2.3 million additional having bilateral low vision. Traumatic cataract is a common sequel after ocular trauma which can result from direct injury to crystalline lens by a foreign object or contusion injury to the globe . Ocular trauma accounts for around 40% of monocular blindness,(1,2) proportion of traumatic cataract being 27-65% cases.(3,4)Childhood trauma of eye accounts for approximately 4 to 20% of all ocular injuries(5) and unilateral vision loss accounts for approximately 29% in paediatric age group.(6)
Ocular trauma has been found to be more common in rural India and In addition to visual morbidity, the economical burden in managing the traumatic cataract can limit the successful outcome. Since the most vulnerable age groups are children and young adults, blindness arising secondary to ocular trauma can significantly affect the quality of life years ahead. Visual acuity >20/60 or ≥20/40 has been kept as a reference mark for final visual outcome and the percentage of patients achieving the same has varied from 40 to 80%.(7,8,9,10)
Successful outcome of traumatic cataract depends on many factors like age,(11) gender,(7) type of injury,(11) duration of injury, timing of presentation, interval from presentation to surgical intervention, initial visual acuity,(9)type and number of surgeries, extent of damage, postoperative visual gain, primary or secondary intraocular lens implantation,(10) surgical complications and traumatic squeal.Many landmark studies have been done for traumatic cataract highlighting the importance of one or the other factor, but none has taken into account of all the factors simultaneously.(11,7,9) Additionally, none of the studies have been reported from southern part of India where the burden of ocular trauma is significantly higher.
Keeping this in mind we did a multifactorial retrospective analysis of all traumatic cataract cases presenting to a tertiary eye care hospital in South India. The aim of present study is to highlight the predictors of final visual outcome following traumatic cataract surgery, associated ocular morbidity hampering final visual outcome along with special reference to demographic profile of the patients, mode of injury,type of trauma, time, type and number of surgeries.
MATERIAL AND METHODS
We retrospectively analyzed all the cases of traumatic cataract presenting to the tertiary eye care center from January 2012 to December 2014. Ethical clearance was taken from institutional ethical committee review board. All the case sheets were reviewed for the eligibility of inclusion into study and data was recorded into Microsoft Excel sheet (Microsoft Office 2010). Patients of all age groups with minimum of 3 months follow up from presentation were included. Patients with insufficient medical records, less than 3 months follow up, lens status not clear on presentation, cataract attributed to complication of steroids or inflammation, operated outside our hospital and incomplete diagnosis were excluded from the study.
The following data was analyzed and documented:age, gender, mode of injury, duration of defective vision before presentation,duration of injury at presentation, type of injury (open globe or closed globe), interval between defective vision and surgery, uncorrected and best corrected visual acuity (UCVA and BCVA) at presentation and all the postoperative visits (1,3,6,9,12 months and last visit) after primary surgery, intraocular pressure (IOP), anterior segment (including type of traumatic cataract) and posterior segment findings, gonioscopy findings, type of intraocular lens (IOL) used,primary or secondary IOL placement, type of cataract surgery and number of surgeries performed per patient, intraoperative or postoperative complications, follow up duration, reasons for poor visual outcome were retrieved from casesheets. Any special procedure performed like capsular tension ring (CTR) placement, core vitrectomy, intraocular foreign body removal, retinal detachment repair was also recorded.
Surgical protocol followed at the institution:
All the injuries whether open or closed are evaluated for the extent of ocular and systemic injury. Diagrammatic depictions are made in the case records. Anterior segment is evaluated by cornea consultant and posterior segment by Vitreo-retinal consultant. Ultrasound B-scan is performed whenever the posterior segment is not visible. Appropriate cross specialty referral and management is done depending on the course of disease. Primary repair is done as soon as the patient is systemically fit for surgery. Lens removal is done in case of visually significant traumatic cataract or subluxation or breached anterior lens capsule. Posterior capsule is preserved to the extent possible. Additional posterior segment medical or surgical intervention is performed based on the individual case scenario as deemed fit by Vitreo-retinal consultant. Primary or secondary IOL placement decision is dependent on multiple factors including the extent of injury, adequate capsular support, reliable preoperative IOL biometry, intraoperative complication and surgeon’s discretion. In general, secondary IOL placement is preferred for majority of the open globe injuries but in subjects where the extent of injury is limited and IOL biometry is reliable, a primary IOL placement is planned for. Primary IOL placement is preferred in closed globe injury subjects, until otherwise contraindicated. Secondary IOL placement is planned after a period of minimum 1 month post primary surgery.
STATISTICAL ANALYSIS
STATA software 12.0 was used for statistical analysis. The parameters were divided into categorical and continuous variables. Chi square test was used to analyze two categorical variables, unpaired Student –t test to compare mean of two age groups and Mann- Whitney test for comparing non parametric variable. Univariate and multivariate linear regression model was done to analyze different variables over final BCVA. Binomial logistic regression analysis was performed to compare the influence of different variables in achieving final BCVA of better than 0.3 Log MAR units.Different groups were created for the purpose of statistical analysis: Age group was divided into group 0 (≤16 years) and group 1 (>16 years). Duration of DV before surgery was divided into four groups (G1- ≤48hours; G2- 3 to 7 days; G3- 8 to 30 days and G4 >30 days). Final BCVA (best corrected visual acuity) was divided into two groups (group 0 – less than 6/12 or >0.3LogMAR unit; group 1 – better than 6/12 or <0.3 LogMAR units)
RESULTS
Retrospectively 398 patients were diagnosed to have traumatic cataract during a period of three years (2012-2014). Out of 398 patients only 97 were included within the study. Patient were primarily excluded due to incomplete diagnosis, inadequate follow up and insufficient data. Mean age of presentation was 33.4 years with predominant patients being of male gender. Male to female ratio was 2.6:1. Age was divided among two groups i.e. pediatric (≤16 years) and adults (>16 years). Twenty six eyes belonged to pediatric age group (≤16 years). Mean age of presentation in pediatric group was 10.5±3.6 years and in adults was 41.7±15.5 years. All cases were unilateral in presentation with equal distribution between right and left eye (48 and 49 eyes respectively). Out of 97 eyes, 53 (54%) eyes had closed globe injury and 44 (45%) eyes had open globe injury. Gender and age group wise distribution was similar across open and closed globe injury (p=0.87 & p=0.71 respectively). Post cataract surgery mean follow up duration was 11.9 ± 9.33 months (range 1 to 41 months). Twenty different mode of injuries were noted with wooden stick injury (25 eyes) being the most common followed by vegetative matter (14 eyes) and iron material (12 eyes). In the pediatric age group cracker burst injury was the most common followed by stick injury. Other less common mode of injuries were stone injury, road traffic accident, needle, broken glass, pencil, cracker burst, cricket ball, bottle cap, pressure cooker, plastic material, toy, finger nail, cow horn, animal parts and unknown. Duration of injury (DOI) and defective vision (DV) at presentation were widely distributed over a range of 1 day to 2500 weeks [95% CI=84.8 – 272.2 weeks] and 1 day to 2080 weeks [95% CI=43.8 – 177.1 weeks] respectively, with a median value of 1.5 week and 1 week respectively. Mean duration of DV at the time of surgery was 19.1 ± 12.4 days [range: 1 – 40 days; 95% CI=16.7 – 21.7 days]. Due to the wide variability in DOI and DV at presentation, eyes were divided into 4 groups based on duration of DV at the time of surgery (as mentioned in methodology).
Cataract morphology at the time of presentation has been described in table .
Table 1: Distribution of cataract morphology (number of eyes)
| Type of cataract | Rosette | PSCC | Total cataract | Subluxated | Immature cataract | ASCC | Focal | HMC |
| No. of eyes | 12 | 23 | 47 | 9 | 4 | 7 | 9 | 1 |
*PSCC – posterior subcapsular cataract; ASCC – anterior subcapsular cataract; HMC – hypermature cataract
Thirty four eyes (35%) had rupture of anterior lens capsule on slit lamp examination. Mean ± SD of best corrected visual acuity (BCVA) at presentation was LogMAR 1.98 ± 1.15. In total 138 surgeries were performed for 97 eyes including 10 eyes which didn’t undergo any surgical intervention due to poor visual prognosis, cataract of localized extent and associated ocular morbidity limiting surgical success. Thirty eight eyes (39%) underwent more than one surgeries. Significantly (p = 0.005) higher number of surgeries were performed in open globe injury patients (mean ± SD: 1.81 ± 0.73) as compare to closed globe injury group (mean ± SD: 1.36 ± 0.71).
Comparative data between open and closed globe injury eyes has been listed in table 2. BCVA improved significantly in both the groups (p<0.005) and the final BCVA was similar.
Table 2: Comparison of different variables between open and closed globe injury
| Open globe injury | Closed globe injury | P-value | |
| Number of total eyes | 44 | 53 | – |
| No. of Pediatric eyes (≤16 years) | 11 | 15 | – |
| No. of adult eyes | 33 | 38 | – |
| Age (mean) in years | 30.25 | 36 | 0.15# |
| Pediatric age (mean) in years | 10.5 | 10.6 | 1.0# |
| Adult age (mean) in years | 36.8 | 46 | 0.01# |
| Duration of Injury at presentation (weeks) | 75.9 ± 228.5 | 263.6 ± 582.0 | 0.0002* |
| Duration of DV at presentation (weeks) | 78.6 ± 226.9 | 136.8 ± 396.9 | 0.006* |
| Duration of DV before surgery (days) | 19.1 ± 12.2 | 19.2 ± 12.6 | 0.86* |
| BCVA at presentation (mean±SD) | 2.36 ± 0.99 | 1.66 ± 1.19 | 0.002* |
| BCVA at final visit (mean±SD) | 0.55 ± 0.99 | 0.49 ± 0.89 | 0.8* |
| Change in BCVA (Delta) (mean±SD) | -1.81 ± 1.28 | -1.16 ± 1.13 | 0.008* |
# Unpaired Student T-test *Two-sample Wilcoxon rank-sum (Mann-Whitney) test
Intraoperative complications within the two groups have been mentioned in table 3. Posterior capsule rent and zonular dialysis were more common in closed globe injury.
Table 3: Distribution of number of eyes among open (OGI) and closed (CGI) globe injury patients
| Intraop_Complication | OGI | CGI |
| Nil | 39 | 35 |
| Posterior capsule rent | 1 | 5 |
| Cortex drop | 1 | 0 |
| Zonular dialysis | 1 | 2 |
| Anterior segment foreign body | 2 | 0 |
| Whole bag removal | 0 | 1 |
Majority of the patient achieved a final BCVA better than 1.0 LogMAR. Postoperatively poor visual outcome (< 1.0 LogMAR) was observed in 18 eyes (18.5%) and the causes were macular scarring (4 eyes), retinal detachment (5 eyes), amblyopia (3 eyes), corneal scarring (3 eyes), advanced glaucoma (2 eyes) and endophthalmitis (1 eye). Strabismus (5 eyes) and corneal scarring (2 eyes) were the only pre-existing ocular co-morbidities but were found to be not responsible for poor visual outcome. Seventy four eyes (76%) achieved visual acuity of ≥6/12 (≤0.3 LogMAR). Age group wise 80% of pediatric eyes and 74.6% of adult eyes achieved visual acuity of equal to or better than 6/12. The difference was not significant (p=0.21).
Both univariate and multivariate linear regression analysis were done to evaluate the influence of different factors on final BCVA. In univariate regression analysis BCVA at presentation, IOL placement (aphakia v/s primary or secondary), UCVA on day 1 post op, BCVA at 1 month and 3 month post op were all found to be significantly associated with final BCVA (table 4). However, after adjusting for age, gender (male v/s female), type of injury (open v/s closed), duration of injury, duration of defective vision at the time of presentation and surgery; BCVA at presentation, 1 month, 3 month, 6 month and 12 month post op; UCVA on post op day 1, IOL placement and total number of surgeries only UCVA post op day 1 and BCVA at 1 month post op were found to be significantly associated with final BCVA. IOL placement had a borderline significant value (table 5).
Table 4: Univariate linear regression analysis of factors significantly associated with dependent variable final BCVA*
| FinalBCVA | Coef. | Std. Err. | t | P>t | [95% Conf. | Interval] |
| BCVA at presentation | .251896 | .0788344 | 3.20 | 0.002 | .0953898 | .4084021 |
| Primary IOL placement | -.7283142 | .261733 | -2.78 | 0.007 | -1.248985 | -.2076439 |
| Secondary IOL placement | -.9978462 | .285597 | -3.49 | 0.001 | -1.56599 | -.4297028 |
| UCVA on POD 1day | .0995082 | .0278654 | 3.57 | 0.001 | .0441883 | .1548281 |
| BCVA1month | .1045675 | .0309525 | 3.38 | 0.001 | .0431191 | .1660159 |
| BCVA3month | .076929 | .0339237 | 2.27 | 0.026 | .009582 | .1442759 |
*BCVA – best corrected distance visual acuity; IOL – Intraocular lens; UCVA – uncorrected distance visual acuity
Table 5: Multivariate linear regression analysis of factors related with dependent variable final BCVA*
| FinalBCVA | Coef. | Std. Err. | t | P>t | [95% Conf. | Interval] |
| Age (in years) | .0041183 | .0037569 | 1.10 | 0.277 | -.0033746 | .0116112 |
| Sex (Male versus Female) | .1539393 | .1538107 | 1.00 | 0.320 | -.1528265 | .4607051 |
| Type of injury (OGI versus CGI) | -.0381942 | .1621272 | -0.24 | 0.814 | -.3615467 | .2851583 |
| Duration of injury at presentation | .0000666 | .0002535 | 0.26 | 0.794 | -.0004391 | .0005722 |
| BCVA at presentation | .1209879 | .0708592 | 1.71 | 0.092 | -.0203364 | .2623121 |
| Duration of DV before primary surgery | -.000241 | .0068025 | -0.04 | 0.972 | -.0138081 | .0133262 |
| UCVA on POD 1day | .1043136 | .0270502 | 3.86 | 0.000 | .0503637 | .1582634 |
| BCVA at 1month | .1249937 | .0274937 | 4.55 | 0.000 | .0701594 | .1798281 |
| BCVA at 3month | .018775 | .0279638 | 0.67 | 0.504 | -.036997 | .074547 |
| BCVA at 6month | .0251565 | .0314459 | 0.80 | 0.426 | -.0375603 | .0878733 |
| BCVA at 12month | .0200489 | .0355442 | 0.56 | 0.575 | -.0508417 | .0909396 |
| Total number of Surgeries | .0661946 | .1139458 | 0.58 | 0.563 | -.1610632 | .2934523 |
| IOL placement (aphakia versus primary of secondary) | -.2808672 | .1334199 | -2.11 | 0.039 | -.5469649 | -.0147695 |
| Duration of DV at presentation | .0002007 | .0003141 | 0.64 | 0.525 | -.0004257 | .0008271 |
| _cons | -1.230787 | .3603663 | -3.42 | 0.001 | -1.949515 | -.5120589 |
*BCVA – best corrected distance visual acuity; IOL – Intraocular lens; UCVA – uncorrected distance visual acuity; DV – defective vision; OGI – open globe injury; CGI – closed globe injury
Final BCVA was divided into two groups (>0.3 LogMAR versus ≤0.3 LogMAR unit). Univariate (table 5) and multivariate (table 6) logistic regression model was used to analyze the odds of achieving final BCVA of ≤0.3 LogMAR.
Table 5: Univariate logistic regression analysis for dependent categorical variable final BCVA*
| Final BCVA (>0.3 versus ≤0.3 LogMAR unit) | Odds Ratio | P-value | 95% CI (confidence interval) |
| IOL placement (aphakia versus primary or secondary) | 3.89 | 0.004 | 1.54 – 9.81 |
| BCVA presentation | 0.48 | 0.008 | 0.28 – 0.82 |
| UCVA POD 1 day | 0.73 | 0.0001 | 0.61 – 0.86 |
| BCVA 1 month | 0.76 | 0.003 | 0.63 – 0.91 |
Table 6: Multivariate logistic regression analysis for dependent categorical variable Final BCVA*
| Final BCVA (>0.3 versus ≤0.3 LogMAR unit) | Odds ratio | Std. Err. | Z | P>Z | 95% CI | |
| Ageyears | .9968716 | .0316821 | -0.10 | 0.921 | .9366704 | 1.060942 |
| Sex (Male versus Female) | .2695272 | .3498587 | -1.01 | 0.312 | .0211692 | 3.431637 |
| Type of injury (OGI versus CGI) | .0296604 | .0489511 | -2.13 | 0.033 | .0011678 | .7533361 |
| Duration of injury | 1.008016 | .0156278 | 0.51 | 0.607 | .9778468 | 1.039116 |
| Duration of DV at presentation | .9914871 | .0152067 | -0.56 | 0.577 | .9621261 | 1.021744 |
| BCVA at presentation | .5353561 | .3367978 | -0.99 | 0.321 | .1560067 | 1.837139 |
| Duration of DV before surgery | 1.096347 | .0705472 | 1.43 | 0.153 | .9664409 | 1.243715 |
| UCVA on POD 1day | .3936939 | .1418405 | -2.59 | 0.010 | .1943063 | .7976833 |
| BCVA at 1month | .5991976 | .1438709 | -2.13 | 0.033 | .3742755 | .9592871 |
| BCVA at 3month | 1.076294 | .2378013 | 0.33 | 0.739 | .6980111 | 1.659584 |
| BCVA at 6month | .8133772 | .2278518 | -0.74 | 0.461 | .4697259 | 1.408444 |
| BCVA at 12month | .9910156 | .2757281 | -0.03 | 0.974 | .5744504 | 1.709655 |
| Total number of Surgeries | .8573495 | .6481998 | -0.20 | 0.839 | .1948078 | 3.773197 |
| IOL placement (aphakia versus primary or secondary) | 4.490989 | 4.495237 | 1.50 | 0.133 | .6314447 | 31.94101 |
| _cons | 265633.1 | 993416.3 | 3.34 | 0.001 | 174.1622 | 4.05e+08 |
*BCVA – best corrected distance visual acuity; IOL – Intraocular lens; UCVA – uncorrected distance visual acuity; DV – defective vision; OGI – open globe injury; CGI – closed globe injury
After adjusting for all the variable, it was observed that patients having better post op day 1 UCVA and 1 month BCVA had significantly higher chances of achieving final BCVA of better than 6/12 (0.3 LogMAR). Though type of injury appears to be significant in multivariate logistic analysis, cross tabulation revealed no significant difference (Chi-square test; p=0.50).
IOL placement was dependent on the extent of injury and ability to get suitable preoperative IOL biometry readings. Primary IOL placement was preferred in closed globe injury in comparison to open globe injury (table 7). Due to small sample size no statistical significance could be obtained on comparing final BCVA among different groups.
Table 7: Age group wise number of eyes undergoing primary or secondary IOL placement in open and closed globe injury
| Age group | IOL placement (eyes) | Open globe injury (n=11 eyes) | Closed globe injury (n=15eyes) |
| Pediatric (≤16 years;n=26) | Primary IOL placement (n = 16) | 5 | 11 |
| Secondary IOL placement (n=4) | 4 | 0 | |
| Grand total | 9* | 11* | |
| Age group | IOL placement (eyes) | Open globe injury (n=33 eyes) | Closed globe injury (n=38eyes) |
| Adults (>16 years;n=71) | Primary IOL placement (n=31) | 6 | 25 |
| Secondary IOL placement (n=21) | 17 | 4 | |
| Grand total | 23* | 29* |
*Remaining eyes were either not operated or aphakic at the time of last visit to the hospital
DISCUSSION
Visual outcome and the predictive variables in traumatic cataract has been reported in multiple previous literature.(7-14) Different variables have been evaluated on an individual basis andcollectively. Few of the studies have taken either type of injury(8), type of surgery,(10) timing of surgery or IOL implantation(10) into account. Other studies have taken into account different prognostic factors.(11,7,9) Except few studies (9,12,14) most of them include traumatic cases managed before 2010. Factors which have been suggested to have significant influence on the final visual outcome are age(11), gender(7), open globe injury(11), initial visual acuity(9) and type of surgery.(7,9)Limited literature is available on the role of primary or secondary IOL (intraocular lens) implantation(10), duration of injury, early or late presentation, timing of primary surgery(10) and post-operative visual gain. Recent technological advances in the field of surgical management of ocular trauma has increased the chance of better visual recovery and reduced post-operative complications. Literature search on PubMed did not reveal any study which has evaluated visual outcome of traumatic cataract and its prognostic factors from southern part of India. Also none of the study have analyzed multiple factors simultaneously through regression analysis. This study was primarily aimed to address the lacunae in existing literature and evaluate multiple prognostic factors for final visual outcome.
We studied a heterogenous sample of 97 eyes with male preponderance and a mean age of 33.4 years. Both right and left eye were equally affected. A little more than half of the eyes were classified as closed globe injury which was similar to what was reported by Krishnatreya et al(12) but in contrary with other similar studies.(9,14)Like most other studies,(7,12) stick was the most common source of injury but specifically in pediatric age group cracker burst injury was the most common. Second most important object of injury was vegetative matter like thorns. Overall age or gender wise there was no significant predilection towards a particular type of injury (open versus closed globe), but in the subset of adult population, young adults were at higher risk of open globe injury. This finding was in contrary to previous studies where overall males were found to be at a higher risk of open globe injury and female at closed globe injury.(12,14) This could be attributed to various reasons like the regional difference in the demographics, heterogenocity of sample population and working conditions.
As expected OGI and pediatric patients presented significantly earlier as compare to their counterpart but the mean interval between onset of defective vision and primary surgery was the same across different groups. Normally due to nature of emergency we would expect a shorter interval between presentation and surgery for both pediatric and OGI patients but the results of our study suggested otherwise. The confounding factors here was the duration range which was widely distributed for DOI and DV at presentation in comparison to DV at the time of surgery.
Two out of every 5 eyes required more than one surgery i.e. on an average of 1.5surgery/eye. The number of surgeries were higher in OGI patients implicating a step wise surgical approach by the institution. This finding is very perspective and can vary as per the institution management guidelines. In our study the IOL implantation rate was on a lower side (73% and 81% for OGI and CGI respectively) as compare to other studies,(7,8) probably due to shorter duration of follow up.
Clinical endpoint for all the traumatic cataract patients is the final visual acuity and our study reports a significant improvement in BCVA among both OGI and CGI group. Almost three-fourth of our study population achieved a BCVA of ≥6/12 which was similar across pediatric and adults patients and way higher than previously reported by various authors.(7,9,13,14)In difference to a study done by Ram et al(8)the percentage of patients achieving final BCVA ≥6/12 in our study is higher in OGI group. In our study factors which could independently influence final visual outcome werebetter initial visual acuity, primary or secondary IOL placement, better immediate and 1month postoperative visual gain. However, after adjusting for different variables, UCVA on day 1 post-op and BCVA on 1 month post-op were the two most important prognostic variables. Such a finding has neither been evaluated nor reported in any of the previous studies. There are two important clinical interpretations from the above result. First, the immediate visual gain after primary surgery is the most crucial factor for a better final visual outcome. Secondly, visual stabilization is achieved by the end of 1 month post primary surgery and henceforth additional visual rehabilitation surgery can be planned, until otherwise contraindicated.
Primary or secondary placement of IOL has always been the question of interest in traumatic cataract. In our study we did not find any significant difference in the final visual gain between primary or secondary IOL placement either in pediatric or adult population, as was reported by Rumelt et al.(10) However, a very important observation was that patient who were left aphakic had a significantly lower chances of better visual outcome. Thus, it is recommended that as per the clinical scenario either primary or secondary IOL placement should be planned. In case of planning secondary IOL, it can be done earliest at one month post primary repair.
In conclusion ocular trauma is more common in young age with male predominance. Wooden stick remains the most common object of injury but in children cracker burst injury forms a major proportion. It is to be expected that the ocular trauma patients may require more than one surgery. With the recent advances, significant visual improvement and better final visual acuity is expected in three-fourth of the subjects. IOL placement either primary or secondary is to be preferred over aphakia. Instead of age, gender, type of injury, initial BCVA, duration of injury, early or late surgical intervention, the two major prognostic factors for final visual gain are immediate post-op uncorrected visual acuity and 1 month post-op best corrected visual acuity for both pediatric and adult population.
Strength of our study resides in the exhaustive nature of data collection, multifactorial analyses, heterogenous population and clinically reproducible results.
Limitation of our study is the retrospective nature, variability in presentation, multiple surgeons, small sample size, lack of standard reporting format andlimited duration of follow up.
1.Thylefors B: Epidemiologic patterns of ocular trauma. Aust N Z Jophthamol. 1992;20:95
2.Negrel AD, Massembo-Yako B, Botaka E: prevalence et causes dececiteouCongo.Bull WHO. 1990;68:237
3.Kuhn F, Morris R, Witherspoon CD, Mester V (2004) The Birmingham Eye Trauma Terminology system (BETT). J Fr Ophtalmol 27:206–210
4.Dannenberg AL, Praver LM, Brechner RJ, Khoo L (1992) Penetrating eyeinjuries in the workplace. The National Eye Trauma System Registry. Arch Ophthalmol 110:843–848
5.Lambert SR, Drack AV. Infantile cataracts. SurvOphthalmol. 1996;40:427Y458
6.Eckstein M, Vijayalakshmi P, Killedar M, et al. Aetiology of childhoodcataract in South India. Br J Ophthalmol.1996;80:628Y632
7.Gogate P, et al.Causes , epidemiology , and long-term outcome of traumatic cataracts in children in rural India. Indian J Ophthalmol. 2012 Sep-Oct;60(5):481-6. doi: 10.4103/0301-4738. 100557
8.J, et al. Effect of penetrating and blunt ocular trauma on the outcome of traumatic cataract in children in northern India. J Trauma Acute Care Surg. 2012 Sep;73(3):726–30. doi: 10.1097/TA.0b013e31825eeac9.
9.Qi Y et al. Prognostic Factors for Visual Outcome in Traumatic Cataract Patients. J Ophthalmol. 2016;2016:1748583. Doi: 10:1155/2016/1748583
10. Rumelt S, et al. The influence of surgery and intraocular lens implantation timing on visual outcome in traumatic cataract. Graefes Arch Clin Exp Ophthalmol. 2010 Sep;248(9): 1293-7. Doi: 10.1007/s00417-010-1378-x. Epub 2010 Jun 29
11.Shah M et al. Visual recovery and predictors of visual prognosis after managing traumatic cataracts in 555 patients. Indian J Ophthalmol. 2011 May-June;59(3):217-22. Doi: 10.4103/0301-4738.81043
12.Mousumi Krishnatreya, Kabindra Deva Sarma. Clinicoepidemiological Study on Traumatic Cataract. International Journal of Contemporary Medical Research 2016;3(5):1539–41.
13.Adlina A, et al. Clinical profile and visual outcome of traumatic paediatric cataract in suburban Malaysia : a ten-year experience. Singapore Med J. 2014;55(5):253–6.
14.Sharma AK et al. Visual Outcome of Traumatic Cataract at a Tertiary Eye Care Centre in North India: A Prospective Study. J Clin Diagnostic Res. 2016 Jan;10(1):NC05-8. Doi: 10.7860/JCDR/2016/17216.7049. Epub 2016 Jan 1.