Local toxicity was defined by the presence of a local reaction in the form of swelling, bleeding from fang marks, cellulitis, or necrosis. Clinical features such as bleeding from mucocutaneous sites, systemic bleeding, intravascular hemolysis including disseminated intravascular coagulation (DIC), or a deranged laboratory coagulation profile which includes 20 minutes whole blood coagulation time, bleeding time, clotting time, APTT (Activated partial thromboplastin time) anytime during hospital stay indicated a vasculogenic bite. The neurotoxic bite was considered in case of paresthesias, taste and smell abnormalities, ptosis, cranial nerve palsy, general flaccidity, or even respiratory paralysis. Polyvalent anti-snake venom (ASV) and other supportive therapy were instituted as per hospital protocol.

Bedside ophthalmological evaluation was done initially by recording visual acuity, ocular position, extraocular movements, and anterior segment evaluation were done. The fundus examination was done after dilating with tropicamide eye drops 0.8% when possible.

Later when the patient became ambulatory detailed evaluation was done in the ophthalmology outpatient department. Response to treatment and the residual ocular morbidity was also recorded.

A detailed proforma was prepared for the purpose of recording the following data as observations from the present study. Socio-demographic profiles of the snakebite victims, the pattern of snakebites, time and place of occurrence of the snakebite, trends of snakebite, site, and human activity at the time of the bite, details of the circumstances leading to the event; and post-bite factors including the outcomes and other relevant epidemiological data, etc. The ocular morbidity profile, as well as laboratory profile, included blood profile and other important information was obtained from the records. The collected data were analyzed using appropriate statistical methods.

A total of 124 patients were presented to the pediatric department and included in the study. As Table 1 shows the demographic profile of study participants, it can be observed that males (75.81 %) were a more common victim of snakebite whereas lower limb (89.50 %) being the common site of snake bite.

From Table 3 it can be observed that the ocular manifestations of vasculotoxic snake bite. Sub conjunctival hemorrhage(90.90%) being the commonest followed by retinal hemorrhage, vitreous hemorrhage, lid edema, hyphema, anterior uveitis, and significant persisting visual impairment.

Table-3: Ocular manifestations of vasculotoxic snake bite, 11 patients (73.33 % of all patients that had ocular manifestations, N= 11) (here data are not mutually exclusive).

The present study highlights the burden of ocular manifestations of snakebite and its long-standing visual impairment in the pediatric population. Most of the literature state about the ocular complications of snakebite envenomation among adults. There is a significant lack of knowledge of the clinical-epidemic profile of snakebite cases in the pediatric age group. Out of 124 cases of snakebite that were admitted in the hospital during the study period, 15 cases (12.09 %) had ocular manifestations and were analyzed.

Snake venom is a complex mixture of several enzymes and proteins, toxic polypeptides, and inorganic components. it contains numerous toxins, and their combined action has a more potent effect than that of their individual effects. In general, venoms are described as either neurotoxic or hematotoxicity [12]. Cobra and krait are neurotoxic, whereas Viperidae species show characteristic vasculotoxic and haematotoxic features. Patil VC et al reported that 85.43% cases in their series were vasculotoxic and 14.56% were neurotoxic [13]. Males were more commonly affected than females. Brunda G et al reported 76% cases of snakebite to be males [2]. It was also observed that a male preponderance and higher incidence of vasculotoxic bites in our series.

Ocular manifestations were more common in vasculotoxic snake bite in the present study. The commonest finding is subconjunctival hemorrhage

Out of 15 cases that had ocular manifestations in the present study only 3 cases suffered significant visual impairment at the end of six months follow up. One patient had a persistent uniocular vitreous hemorrhage, the second patient had bilateral late-onset severe uveitis along with vitreous hemorrhage, and the third patient suffered from optic neuritis sequelae along with hemorrhage on the macula. The first patient refused any intervention in his eye.

Limitations of the study

As no study is without limitations so this also true for the present study. In developing countries like ours, snakebite victims may preferentially attend traditional healers and may not seek treatment at hospital thus the true burden of disease is not reflected here. Besides, the study duration is short, and the follow up was only for six months.

This study highlights the spectrum of ocular manifestations in venomous snake bites in a pediatric population. There is an urgent need to develop health intervention strategies specially for children to achieve more rapid access to antivenom in health facilities.

Early treatment and close monitoring will help to reduce ocular morbidity. Health education to increase awareness about the hazards of snakebite, early hospital referral, and effective treatment will reduce the global burden of human suffering inflicted by this neglected tropical disease.

Dr. Subhasis Jana: Concept, study design

Dr. Soumya Ray: Manuscript preparation

Prof. (Dr.) Mousumi Banerjee: Manuscript preparation

The authors acknowledge the support of the clinicians and other staff of the Paediatrics department. The assistance from every member of the Ophthalmology department is highly appreciated.