| Primary tumor (pT) |
| pTX |
Primary tumor cannot be assessed |
| pTO |
No evidence of primary tumor |
| pT1 |
Tumor confined to the eye with no optic nerve or choroidal invasion |
| pT2 |
Tumor with minimal optic nerve or choroidal invasion |
| pT2a |
Tumor superficially invades optic nerve head, or tumor exhibits focal choroidal invasion but does not extend past lamina cribrosa |
| pT2b |
Tumor superficially invades optic nerve head and tumor exhibits focal choroidal invasion but does not extend past lamina cribrosa |
| pT3 |
Tumor with significant optic nerve and/or choroidal invasion |
| pT3a |
Tumor invades optic nerve past lamina cribrosa but not to surgical resection line, or tumor exhibits massive choroidal invasion |
| pT3b |
Tumor invades optic nerve past lamina cribrosa but not to surgical resection line and exhibits massive choroidal invasion |
| pT4 |
Tumor invades optic nerve to surgical resection line or exhibits extra-ocular extension elsewhere |
| pT4a |
Tumor invades optic nerve to resection line, but no extra-ocular extension identified |
| pT4b |
Tumor invades optic nerve to resection line, and extra-ocular extension identified |
| Regional lymph nodes (pN) |
| pNX |
Regional lymph nodes cannot be assessed |
| pNO |
No regional lymph node metastasis |
| pN1 |
Regional lymph node involvement (preauricular, cervical) |
| pN2 |
Distant lymph node involvement |
| Metastasis (pM) |
| pMX |
Presence of metastasis cannot be assessed |
| pM0 |
No distant metastasis |
| pM1 |
Metastasis to sites other than central nervous system |
| pM1a |
Single lesion |
| pM1b |
Multiple lesions |
| pM1c |
Central nervous system metastasis |
| pM1d |
Discrete masses without leptomeningeal and/or cerebrospinal fluid involvement |
| pM1e |
Leptomeningeal and/or cerebrospinal fluid involvement |
