Omnigen (OG) is a low-temperature vacuum-dehydrated amniotic membrane transplant (AMT). Dehydrated AMs are one of the methods for AM preservation that can be stored at room temperature, rendering AMs more feasible for transportation and preservation. Dehydrated AM only require a small droplet of balanced salt solution to be rehydrated before manipulation. In contrast, cryopreserved AMs must be stored in the frozen state which is more expensive during transportation. Omnilenz-Omnigen complex is placed onto the ocular surface, without any need for suturing or gluing. Moreover, its application can be repeated. The AM usually lasts for a few days (usually around 7 days).

In the current study, we evaluate the use of Omnilenz in 23 eyes with acute chemical eye injury mostly after alcohol and alkaline exposure. Complete epithelial healing with the restoration of limbal vascularity was achieved in more than half of the eyes after the first application. Five eyes required a second application. All patients were followed up for at least one month. We did not encounter special complications related to the Omnilenz itself in any of our patients.

In our study, Omnilenz was applied within 2 days after the injury. Encouraging results of immediate application have been demonstrated by various studies [8, 9]. Such early intervention was rendered feasible, mostly because of the easiness of application of Omnilenz in the clinic. Prabhasawat et al. [10] showed that AMT performed within 5 days in eyes with grades II and III CEI resulted in earlier epithelial healing and less limbal stem cell deficiency (LSCD) than AM later.

In addition to the lapse in time after chemical injury, the severity of the injury is another factor that seems to affect the final outcome. It has been shown that eyes with a low-grade chemical burn gain benefit from AMT while this influence could not be achieved in eyes with severe injuries [11]. In this context, we found that Omnilenz was not effective in the restoration of ocular surface integrity in eyes with severe burns (grade IV in the Roper-Hall classification). In agreement, Meller et al. [12] analyzed the clinical outcome of AMT in patients with acute CEI. They concluded that in severe cases, AMT could not restore the limbal cell population. This limitation has been reported also in another published study [13].

In etiological perspective, alcohol was the commonest causative agent in our series owing to the era of COVID-19 with lots of people using alcohol for hand sterilization and accidental eye injury. Concerning the groups, there were differences in the outcomes. Obviously, the results were more favorable in patients with alcohol injury than alkali injury. Statistical analysis was not carried out owing to the small number in each group. Yet, the outcomes were least favorable in the alkali group. On the other hand, Tejwani et al. [14] reported different results following the use of cryopreserved AM. In their series, alkali injuries had a better prognosis with an overall success rate higher than acid injury.

Mehta et al. [15], in a recent retrospective study, studied the application of Omnilenz in eyes with CEI, 2 eyes with acute and 15 with chronic affection. They reported favorable outcomes in terms of the restoration of BCVA.

Even though limitations do exist as the lack of a control group with AMT with suture, the current study is the first prospective study highlighting the role of Omnilenz in acute CEI. Future large-scale trials with longer follow-up periods will be vital to elucidate more the possible benefits, restrictions, and the perfect timing as well as the grade of chemical burn ideal for the application of the Omnilenz.

In conclusion, Omnilenz proved to be easy to apply in an outpatient clinic setting, reasonably well tolerated by patients, with promising success. Omnilenz might be included in the paradigm of early management of acute ocular chemical burn. The grade of ocular burn on presentation and timing of intervention with AMT were important factors that influence the outcomes.