Introduction: According to WHO, corneal diseases are responsible for nine per cent of all blindness in India. Viral keratitis has become more prevalent now. Adenovirus is the most common cause and tends to become epidemic. It can cause nummular corneal opacities impairing visual function significantly.

Objective: 1. To find out commonest etiological agent of viral conjunctivitis.

2. To determine the most common serotype of adenovirus causing corneal opacity.

Materials and Methods: A cross sectional study was conducted for one year with informed consent among 100 patients attending the Regional Institute of Ophthalmology, Thiruvananthapuram with clinical features suggestive of Viral Conjunctivitis. Detailed clinical evaluation followed by collection of two conjunctival swab for Gram’s staining and for Polymerase chain reaction was done for each patient. PCR sequences obtained were edited in Bio Edit software (V.7.0.9.0) and compared with adenoviral sequences present in GenBank using the BLAST-N program (version 2.2.18). The patients were further followed up weekly until the conjunctivitis resolved. Clinical course of the corneal lesion was followed up for three months.

Results: The major ocular symptoms were redness (100%), pain (59%), watering (56%) and mucoid discharge (41%). Fifty six per cent of the patients had pre-auricular lymph node enlargement. The most common conjunctival findings was acute follicular conjunctivitis with fine petechial hemorrhages (45.8%). Viral PCR was positive in 24 per cent of patients and subtyping showed adenovirus 8 (70.8%), adenovirus 3 (16.6%), adenovirus 19 (8.3%) and adenovirus 24 (4.16%). Twenty one per cent of the patients developed superficial punctate epitheliopathy. Of these, 75 per cent were viral PCR positive. Fifteen per cent of the patients had persistent subepithelial opacity at the end of three months.

Conclusion: Viral conjunctivitis is a common ocular condition among the outpatients. The present study shows that Adenovirus 8 was the most common etiological agent causing viral conjunctivitis and most common serotype causing corneal subepithelial opacities which affect the visual clarity.

Keywords: Corneal lesions ,etiological agent, Allergic conjunctivitis , chronic conjunctivitis.