The calculator in question is the TNM Classification for Iris Melanoma. TNM stands for Tumor, Node, Metastasis, a system used for staging different types of cancer. This particular classification is specifically designed for iris melanoma, a rare form of eye cancer that originates in the iris, the colored part of the eye.

The TNM Classification for Iris Melanoma is used to determine the extent of the cancer in the patient's eye and whether it has spread to other parts of the body. It is a crucial tool for clinicians to decide the most appropriate treatment plan and to predict the patient's prognosis.

The TNM system for iris melanoma includes three components: T (Tumor) describes the size and extent of the primary tumor, N (Node) indicates whether the cancer has spread to nearby lymph nodes, and M (Metastasis) reveals if the cancer has metastasized to other parts of the body.

This classification system is specifically applicable to patients diagnosed with iris melanoma. It is not suitable for other types of eye cancer or melanoma located in other parts of the body. It also may not be applicable in cases where the patient has had previous cancer treatments that could affect the staging.

TNM classification for iris melanoma

# Criteria
 ## Tumor classification
A. Tx: Primary tumor cannot be assessed
B. T0: No evidence of primary tumor
C. T1a: Tumor limited to iris <= 3 clock hours in size
D. T1b: Tumor limited to iris > 3 clock hours in size
E. T1c: Tumor limited to iris with secondary glaucoma
F. T2a: Tumor confluent with or extending into ciliary body, without secondary glaucoma
G. T2b: Tumor confluent with or extending into ciliary body and choroid, without secondary glaucoma
H. T2c: Tumor confluent with or extending into ciliary body, choroid, or both, with secondary glaucoma
I. T3: Tumor confluent with or extending into ciliary body, choroid, or both, with scleral extension
J. T4a: Tumor with extrascleral extension <= 5 mm in largest diameter
K. T4b: Tumor with extrascleral extension > 5 mm in largest diameter
## Lymph node classification
L. Nx: Regional lymph nodes cannot be assessed
M. N0: No regional lymph node metastasis
N. N1a: Metastasis in >= 1 regional lymph nodes
O. N1b: No positive regional lymph nodes, but there are discrete tumor deposits in orbit that are not contiguous to the eye (choroidal and ciliary body)
## Metastasis classification
P. M0: No distant metastasis
Q. M1: Largest diameter of largest metastasis <= 3 cm
R. M1b: Largest diameter of the largest metastasis 3.1-8 cm
S. M1c: Largest diameter of the largest metastasis >= 8.1 cm

# Conditions
- C and M and P
- (D or E or F) and M and P
- G and M and P
- (H or I or J) and M and P
- K and M and P
- ((C or D or E or F or G or H or I or J or K) and (N or O) and P) or ((C or D or E or F or G or H or I or J or K) and (N or O) and (Q or R or S))
- true