A conjunctival biopsy can be helpful in evaluating chronic conjunctivitis and unusual ocular surface diseases, including the following:
squamous lesions of the conjunctiva (eg, conjunctival intraepithelial neoplasia)
conjunctival lymphoid tumors
superior limbic keratoconjunctivitis
Topical anesthetic eyedrops, as well as a pledget soaked with lidocaine 1% or 2%, are applied to the lesion or biopsy site for approximately 30 seconds. Subconjunctival anesthesia (lidocaine 1% or 2% with epinephrine) may also be used; the advantages of injection of lidocaine for local anesthesia are improved analgesia, blanching of the conjunctival vessels, and reduced bleeding. Forceps and scissors are used to snip a conjunctival specimen sufficient for histologic examination. For a subepithelial lesion, a wedge or block is excised. Grasping only the edge of the specimen minimizes crushing and preserves tissue integrity. Gentle cauterization can facilitate hemostasis after the specimen has been removed.
Leung TG, Thorne JE. Conjunctival biopsy. In: Basic Techniques of Ophthalmic Surgery. 2nd ed. San Francisco: American Academy of Ophthalmology; 2015:121–124.
The sample is placed in the proper anatomical orientation on a carrier template (eg, filter paper) and inserted into the appropriate fixative, such as 10% neutral-buffered formalin (for histology), 3% glutaraldehyde (for electron microscopy), or Michel or Zeus transport medium (for immunofluorescence microscopy). Tissue wrapped in a gauze pad soaked with balance salt solution may be submitted to the surgical pathologist for immediate processing if this has been prearranged. A preoperative consultation with the pathologist is advised to ensure proper handling and staining of specimens. See BCSC Section 4, Ophthalmic Pathology and Intraocular Tumors, for further discussion of tissue processing.
Excerpted from BCSC 2020-2021 series: Section 10 - Glaucoma. For more information and to purchase the entire series, please visit https://www.aao.org/bcsc.