Introduction

Ocular disease and injuries represent a sizeable burden to emergency departments, have been associated with long-term sequelae and reduced quality of life.1, 2 The Baltimore Eye Survey has reported a 14.4% cumulative lifetime prevalence of eye injury in the general population.3 Another study has indicated a 13.2 per 100 000 population annual rate of hospitalization due to ocular trauma.4

Ocular trauma is frequently associated with cataractous changes in the lens.5, 6 Traumatic cataract is encountered in 27–65% of the ocular trauma cases.7, 8, 9 It has been reported that ocular trauma occurs in 3.45 per 100 000 population per year or 4.6 per 10 000 outpatient visits.10 Cataract formation is commonly observed as a result of direct injury to the crystalline lens by a foreign object or by blunt trauma to the globe.6, 7 In most cases, the traumatic cataract interferes with the visual axis and requires cataract surgery but in some cases, a minor injury to the lens may result in a localized non-progressive lens opacity that does not require surgery.11 Damage to the zonules may also occur, causing subluxation or total displacement of the crystalline lens,7 which may also necessitate cataract surgery.

Traumatic cataract surgery is performed either as an early procedure in association with the repair of laceration in open globe injury, at early days after presentation of penetrating injury, or as a late procedure in a quiet eye. If the lens capsule is ruptured and lens materials have been introduced into the anterior chamber it is preferable that lensectomy be performed as an early procedure to prevent inflammation, lens particle induced uveitis and glaucoma. Because of corneal irregularity, or associated open globe injury the power of intraocular lens (IOL) is calculated mostly by the biometry of the fellow eye.

Early procedure has the advantage of performing traumatic cataract surgery at the same admission and reducing the cost and time, while the advantages of the late procedure include performing surgery in a quiet eye, better IOL calculation after suture removal and knowing the potential for visual improvement. There is no consensus about the proper timing of traumatic cataract surgery and the influence of it on visual prognosis in the literature. So we performed the present study to compare early and late post traumatic cataract surgeries.

Patients and methods

In a randomized clinical trial, 30 eyes with traumatic cataract after open globe injury underwent early (during the first week after the trauma; Group 1) and 30 eyes underwent late cataract surgery (from the first to second month after the trauma; Group 2) (Figure 1a). All cases were observed for at least a 6-month period after the surgery. Inclusion criteria included patients older than 12-year-old with significant traumatic cataract after open globe injury. Exclusion criteria included patients with anterior capsule rupture as well as disseminated lens materials in the anterior chamber (Figure 1b), patients with hypopyon, eyes undergoing simultaneous primary repair and cataract extraction, cases that IOL implantation was not possible and patients with direct trauma to the posterior segment or with lacerations associated with vitreous prolapse.

Figure 1
figure 1

(a) A patient included in the study that underwent primary repair after a trauma with a metal wire when he was on work. (b) A patient who was referred with a traumatic cataract. He underwent primary repair but as can be seen in the figure lens materials were disseminated in the anterior chamber (AC), this patient was excluded, because the lens materials in AC by oneself is an indication for early cataract surgery.

Full size image

In those cases, that IOL power calculation was not possible by the biometry of the affected eye, it was performed using the biometry of the fellow eye. The Ethics Committee of Tehran University of Medical Sciences approved the conduction of the present study and all procedures started after written informed consent was obtained following the explaining the possible consequences of the different methods of treatment to patients. All procedures were performed by the same surgeon (MBR).

All cases underwent lensectomy using vitrectomy probe through the limbal incision. We excluded those patients who may need pars plana vitrectomy from the study before randomization. They were any vitreous involvement (possibly hemorrhage, fibrin or retinal detachment) in the echography, lacerations involving more than 3 mm of pars plana or lacerations associated with vitreous prolapse. Each case underwent intraoperative fundoscopy after lensectomy. No case needed pars plana vitrectomy during the lensectomy procedure. Anterior capsulectomy was performed using a vitrectomy probe and anterior vitrectomy was performed in cases of posterior capsular rupture or vitreous prolapse because of zonular dehiscence. If there was a too hard nuclear part for the vitrectomy probe, we emulsified and suctioned the nucleus using a phacoemulsification handpiece. If the capsular integrity permitted, a posterior chamber IOL was implanted. In this situation, if posterior capsule was not intact, a three piece acrylic foldable (Alcon MA60) IOL was implanted. In other situations, a one-piece foldable acrylic (Alcon SA60) IOL was implanted.

Patients were randomly assigned for early or late cataract extraction and IOL implantation. Randomization was based on a computer-generated sequence based on permuted block randomization method. The length of blocks varied randomly between two, four and six patients. A biostatistician performed the randomization and the sequence of randomization was concealed from the investigators.

All patients received prophylactic oral antibiotic therapy (ciprofloxacin 750 mg twice daily for three days) following the open globe injury. (1). Following surgery, topical antibiotics, corticosteroids and cycloplegics were prescribed and then topical steroids were continued for four weeks and tapered gradually during this period.

We visited all patients at 1 week, 4weeks and 12 weeks and 6 months after surgery. In each visit, patients were examined regarding visual acuity, intraocular pressure (IOP), anterior chamber inflammation, IOL position and posterior synechiae. In addition, posterior segment evaluation and fundoscopy were performed. Anterior chamber inflammation assessed by Standardization of Uveitis Nomenclature (SUN) Working Group grading scheme for anterior chamber cells and flare and grade ≥2+ was considered significant.12 BCVA (best-corrected contact lens visual acuity) of both eyes was evaluated in logMAR at six months of follow up visits. Another surgeon who did not know timing of the surgery (MS) performed this evaluation.

Sample size was calculated as 30 eyes to have a power of 90% to detect a difference of 0.2 logMAR in BCVA between the two groups when the standard deviation of BCVA was assumed to be 0.24 logMAR and the type I error was 0.05 for two-sided test. To assess for the normal distribution of data we used Q–Q plot and Kolmogorov–Smirnov test. To describe data, we used mean, standard deviation, median and range. To compare the results between two groups we used t-test, Mann–Whitney, Fisher exact, and χ2-tests. All statistical methods were performed using SPSS software (IBM Corp., Armonk, NY, USA, Released 2013. IBM SPSS Statistics for Windows, Version 22.0. IBM Corp.). P-values <0.05 were considered statistically significant.

Results

There were 30 patients in group I with a mean age of 31.1 years (range: 12–67 years). Thirty patients with mean age of 31.8 years (range: 12–69 years) were in group II. Although most of patients in each group were male, there was no significant difference between two groups (Table 1). Intraoperative complications including posterior capsular rupture, anterior vitrectomy and zonulysis at the site of IOL implantation are listed in Table 2. Iris fixation of IOL using a 10–0 prolene was used for three unstable IOL in group I and one case in group II (P=0.309). Three cases of zonulysis were managed using a capsular tension ring (CTR) and a Cionni ring was implanted for the last one. Table 3 shows the BCVA and refractive status in each group. There was no significant difference between the two groups in each parameter. Post-operative complications including raised IOP, significant anterior chamber inflammation (≥2+ according to Standardization of Uveitis Nomenclature (SUN) grading scale), visual axis opacity (VAO), posterior synechiae, subluxation of IOL, IOL pigment deposition are listed in Table 4. All patients with increased IOP were medically controlled except one case in group I that finally underwent shunt procedure bringing it into control. There was not any case of sympathetic ophthalmia in both groups.

Table 1 Baseline characteristics of patients entering the study
Full size table
Table 2 Best-corrected visual acuity at sixth post-operative month among patients entering the study
Full size table
Table 3 Intraoperative complications among patients
Full size table
Table 4 Post-operative complications in early and late cataract surgery groups during six month follow up
Full size table

Discussion

This study was a prospective randomized control study that performed with enrollment of 60 patients with traumatic cataract after open globe injury. The purpose of the study was to determine the proper time for traumatic cataract surgery. A vast majority of traumatic ocular injuries are associated with traumatic cataract.5, 6 Ocular trauma mainly involves children and young men.7, 9 So it is reasonable to perform traumatic cataract surgery as an early procedure in this group to make the period of visual rehabilitation shorter and starting the amblyopic therapy sooner with the help of modern surgical techniques that have yielded good anatomic and functional outcomes in the treatment of traumatic eye injuries recently.13, 14 On the other hand, late cataract surgery could permit to better IOL calculation, probably operating in an eye with less corneal edema and inflammation and better evaluation of the traumatic cataract. One study has been performed by Shah et al.15 to determine the effect of interval between the time of injury and time of intervention on the final visual outcome in cases of traumatic cataract. Their study was a prospective cohort and performed between January 2003 and December 2009. In patients with corneal laceration, traumatic cataract surgery performed as a secondary procedure. This group of patients had a significant higher post-operative inflammation and lower final BCVA. They concluded that it is better to perform the traumatic cataract surgery as an early procedure because of lower complication rate as well as sooner and better visual rehabilitation.15 Some other authors like Memon et al,16 advocate secondary procedure in the absence of fragmentized or intumescent traumatic cataract to manage traumatic cataract. Reasons that Memon et al,16 mention are better assessment of visual improvement after surgery, more accurate IOL calculation and less post-op inflammation. Also Agarwal et al17 have suggested that in the presence of severe corneal damage and edema it is better to postpone lensectomy for better visualization during surgery. There are some special situations which ocular trauma is associated with the rupture of anterior capsule and presence of lens material in anterior chamber. The possibility of IOP rise and prolonged inflammation, which may cause anterior and posterior synechiae, is higher in this situation. The longer existence of synechiae the more difficult the surgery will be. Therefore, the repair of the traumatic wound and lensectomy is better to be done at the same session.12 On the other hand, it is possible that the patient with ocular trauma would have small, peripheral opacity in crystalline lens that does not obscure visual axis. It is better to follow up these cases with regular visits to determine that lensectomy is a good choice for them or not.

In the present study, we tried to make a model to find the proper time of traumatic cataract surgery. We did not include patients who underwent cataract surgery between the first week and the first month, because the “early” time (the first week after trauma) is usually in the same admission period, after one week, up to one month, one could possibly follow the patient in the hope that the inflammation and edema would be improved, also there would be a time lag after primary admission. In this study, the mean BCVA 6 months after surgery was relatively good because associated ocular injuries excluded based on exclusion criteria. Kuhn et al18 have stated that any traumatic injury to ocular tissue in patients with traumatic cataract can lead to a decreased post-operative BCVA. Srivastava et al.19 have reported that demographic variables such as age, sex, and the time of intervention have no association with post-operative BCVA, similar to our results. We found that at 6 months post operative the BCVA showed no difference among patients in two groups. In addition, intra- and post-operative complications were not different between early and late procedure groups.

Posterior capsular rupture was not statistically different between group I and group II (P=0.069). Although not quite reaching statistical significance due to small numbers, there is a trend towards a greater risk (a 20% increase in Table 3) of posterior capsule rupture in group 1.

We found more zonulysis in group II, possibly because during the early procedures, zonulysis had been considered possibly as posterior capsular rupture and had been managed with anterior vitrectomy (probably because of a lower vision during early surgery). Finally, the rate of anterior vitrectomy was not different between early and late procedure groups (P=0.399). Although there are some difficulties during operation such as intraoperative corneal edema that may compromise vision during the operation, the rate of complications was not different between the two groups. The study had some limitations; The follow-up period was 6 months in this study, we need more studies with longer follow-ups in the future. The mean 6 months post-operative BCVA was relatively good among our patients because of strict exclusion criteria such as patients with associated ocular trauma and released lens materials in anterior chamber were excluded from the study, so one of our limitations is that we may not be able to generalize our results to all traumatic cataract patients. The low number of cases in the present study is one of the limitations. In addition, we included the patients undergoing cataract surgery in the first week but not in the primary repair session. Although this was to preserve ethical purposes, one could think about the results of primary repair and lensectomy in the same session. In addition, we only included patients undergoing IOL implantation, thus we do not know the detailed results in aphakic eyes. Finally, according to this study (1) There was no difference regarding visual outcomes between the two groups (2) There was no difference regarding intra- or post- operative complications between the groups (3) So, early and late intervention could be considered equally according to the situation of each case and the treatment environment, (4) However, we need more trials addressing mentioned limitations to say the correct timing of traumatic cataract surgery.