Bacterial Endophthalmitis Workup

Updated: Apr 18, 2023
  • Author: Robert H Graham, MD; Chief Editor: Hampton Roy, Sr, MD  more...
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Laboratory Studies

Perform culture and sensitivity studies on aqueous and vitreous samples to determine the type of organism and antibiotic sensitivity. [9, 10]

Sjoholm-Gomez de Liano et al found that anterior chamber tap has too low a sensitivity and specificity to rely on alone, but could be helpful for therapeutic guidance if better methods of diagnosis are not available. [36]

Polymerase chain reaction (PCR) has been shown to be sensitive and specific in detecting and identifying 12 major microbial species in postoperative endophthalmitis. [37]

If endogenous bacterial endophthalmitis is suspected, a systemic workup for the source is required. This workup includes the following [11] :

  • Blood culture

  • Sputum culture

  • Urine culture


Imaging Studies

B-scan ultrasonography

Perform B-scan ultrasound of the posterior pole if view of fundus is poor.

Typically, choroidal thickening and ultrasound echoes in the anterior and posterior vitreous support the diagnosis.

Occasionally, another source of inflammation other than or in addition to bacteria, such as retained lens material, may be seen.

The ultrasound is also important to provide a baseline prior to intraocular intervention and to assess the posterior vitreous face and areas of possible traction. [12]

Rarely, a retinal detachment is seen concurrently with endophthalmitis.

CT scanning

A CT scan rarely is performed unless trauma is involved. Thickening of the sclera and uveal tissues associated with various degree of increased density in the vitreous and periocular soft tissue structures may be seen.


If an endogenous route is considered, perform other imaging modalities to rule out potential sources, as follows:

  • Two-dimensional echocardiogram

  • Chest x-ray



Anterior chamber tap

A 30-gauge needle on a tuberculin syringe is used to obtain a 0.1 cc sample under topical anesthesia through the limbus.

Vitreous tap

A retrobulbar block or a sub-Tenon block with lidocaine with epinephrine is given.

A sub-Tenon block has the advantage over a retrobulbar block because it does not create increased intraocular pressure that may cause recent surgical wounds to open.

A 21-gauge needle on a tuberculin syringe is used to obtain an adequate vitreous sample of 0.1-0.2 cc. Smaller gauge needles may be used but with increasing difficulty to create the aspiration vacuum necessary to obtain a sample.

Vitreous biopsy

A 23-gauge vitrectomy cutter may be used if available.