$veri = '10,16,22,9';
$veri_arr = explode(',', $veri);

<label style="font-size:18px">
<input type="checkbox" style="width:18px; height:18px; " value="<?php echo $deid = $deger['degere_id']; ?>"  name="deger[]" <?=in_array($deger['degere_id'], $veri_arr) ? 'checked="checked"' : NULL?>> <?php echo $deger['degere_adi']; ?>  
</label>