**2. Sterile/non-infectious endophthalmitis**

Sterile endophthalmitis is an acute intra-ocular inflammation of the vitreous cavity that resolves without the need of intra-vitreal antibiotics and/or vitreo-retinal surgery. In these cases if vitreous microbiological study is done, it needs to be culture negative. This condition has diverse etiologies and includes systemic auto-immune diseases, local ocular inflammations of unknown cause, endophthalmitis related to lens material and endophthalmitis attributable to intra-ocular foreign bodies.

Phacoanaphylactic endophthalmitis (lens-induced granulomatous inflammation) is a type of non-infectious endophthalmitis which represents an auto-immune response to lens protein. This is a rare consequence of lens injury which may occur after trauma causing rupturing of the lens capsule, or post surgery such as following extracapsular cataract extraction when residual lens cortex is present. There is a mixed neutrophilic and granulomatous response seen around the lens in histology [5].

Phacotoxic endophthalmitis is a condition which was previously used to cover a mixed group of conditions related to cataract surgery and intra-ocular lens implant surgery. However, since inflammation is seen mostly in the anterior segment, the term was changed to toxic anterior segment syndrome (TASS). TASS is caused due to reactions to chemicals (irrigationsolutions, preservatives, drugs, denatured viscoelastics), IOL (intra-ocular lens) materials, instrument sterilization and preparation-related compounds [6,7]. TASS presents with marked decrease in vision and diffuse corneal oedema within 12–24 h of anterior segment surgery, most commonly cataract surgery and, more recently, it has been reported after phakic intra-ocular lens implantation [6,8].

Sterile endophthalmitis has also been noted following intra-ocular injection, post vitrectomy and after glaucoma drainage device implantation surgery. Intra-vitreal triamcinolone aceto‐ nide has also been associated with sterile endophthalmitis when triamcinolone crystals migrate into the anterior chamber [9]. Clinically, sterile endophthalmitis presents within 24 h of surgery, Gram stain and culture negative, involving the anterior segment in the case of TASS, and showing no response to antibiotics but improvement is seen with topical and/or oral steroids. However, it is difficult to rule out infectious etiology because some infectious cases mayhave rapid onset and have initial negative cultures [6].
