look up and display only a certain range of rows in R

I am wondering how do I display a certain range of rows based on a fixed value:

y<-c(1,59,60,65,85,86,1550,97)
z<-c(1:8)
test<-cbind(y,z)
test

y z
[1,]    1 1
[2,]   59 2
[3,]   60 3
[4,]   65 4
[5,]   85 5
[6,]   86 6
[7,] 1550 7
[8,]   97 8

So say, it just so happens that I need to see only +/-2 rows from 85, is there a way I can extract from the table? Ideally, I would like to have something like this:

Thanks a lot for helping.

Updated version with new function written by Peter :

#required libiaries

library(quantmod)
library(pedquant)

# download option chain from yahoo finance, using an example of ticker "BABA" & exp= "2023-06-23"
ticker<-c("BABA")
options<-getOptionChain(ticker,Exp="2023-06-23")

# seperate call/put options and display only Strike, Last Price, Volume
call_option<-options$calls[,c("Strike","Last","Vol")]
put_option<-options$puts[,c("Strike","Last","Vol")]

#getting the updated stock price to filter at-the-money level 

ticker_price<-md_stock(ticker,type="real")
price<-ticker_price$close

view_window <- function(dfr, var, x, pm){
  
  idx <- which(abs(test[, var]-x) == min(abs(test[, var] - x)))
  
  return(dfr[(idx - pm) : (idx + pm), ])
  
}

view_window(dfr=call_option,
            var=call_option$Strike,
            x=price,pm=3)

Error in test[, var] : subscript out of bounds

In this example, data frame [dfr] is call_option, var is call_option$Strike, x is the traded price, however, an error msg of "Error in test[, var] : subscript out of bounds" is shown, pretty sure something is wrong with the format of my data frame n the function should have been working perfectly. Any ideas? Many thanks.

You could use a function like this:

# Where
# dfr is your data frame
# var is the quoted variable name you want to use 
# x is the value of the variable you want to centre your subset on, and 
# pm is the plus and minus range of the subset

view_window <- function(dfr, var, x, pm){

  idx <- which(abs(test[, var]-x) == min(abs(test[, var] - x)))
  
  return(dfr[(idx - pm) : (idx + pm), ])
  
}

view_window(dfr = test,
            var = "y",
            x = 85,
            pm = 2)
#>         y z
#> [1,]   60 3
#> [2,]   65 4
#> [3,]   85 5
#> [4,]   86 6
#> [5,] 1550 7

Limits of the function:
if x within the plus or minus index of the first or last value in the subject vector the function will fail.
I've not tested the effect if there are multiple values in the subject column which are equal to x.

^{Created on 2023-06-21 with reprex v2.0.2}