Springer Science and Business Media (www.springerlink.com, accessed 2 March 2009).

pT, primary tumour (melanoma of the conjunctiva confined to the epithelium); pTX, primary tumour cannot be assessed; pT0, no evidence of primary tumour; pT1a, melanoma of the bulbar conjunctiva not more than 0.5 mm in thickness with invasion of the substantia propria; pT1b, melanoma of the bulbar conjunctiva more than 0.5 mm but not more than 1.5 mm in thickness with invasion of the substantia propria; pT1c, melanoma of the bulbar conjunctiva greater than 1.5 mm in thickness with invasion of the substantia propria; pT2a, melanoma of the palpebral, forniceal or caruncular conjunctiva not more than 0.5 mm in thickness with invasion of the substantia propria; pT2b, melanoma more than 0.5 but not greater than 1.5 mm in thickness with invasion of the substantia propria; pT2c, melanoma of the palpebral, forniceal or caruncular conjunctiva greater than 1.5 mm in thickness with invasion of the substantia propria; pT3, melanoma invades the eye, eyelid, nasolacrimal system, sinuses or orbit; pT4, melanoma invades the central nervous system.