House Rule: Called Shots

Found a good one in the Quintessential Fighter:
CALLED SHOTS
There are many more ways to cripple and defeat an enemy besides simply swing a weapon at him again and again. Some instead choose to aim their blows at specific body parts, not only dealing damage but hindering the enemy’s ability to keep fighting.
How it works:
You can make a variety of called shots, provided you meet the requirements listed below.
1. First, you must score a threat against your target.
2. Rather than rolling to confirm a crit, you announce “Called shot to [body part]” instead, then make the roll that would normally confirm the threat.
3. The base damage is applied normally, but if the confirmation roll succeeds, consult the chart below rather than doing normal critial damage.

Arm
• Requirement: BAB +2 or greater
• Effect: Victim drops held item. 1d4 damage. -4 to all checks and attack rolls using wounded arm.
• Duration: d6 rounds

Leg
• Requirement: BAB +2 or greater
• Effect: 1d4 damage. Speed halved. Climb, Jump, and Swim @ -4.
• Duration: d6 rounds

Groin
• Requirement: BAB +2 or greater
• Effect: Victim Staggered for d6 rounds.

Head
• Requirement: BAB +8 or greater
• Effect: 1d4 damage. Stunned: Loses Dex bonus to AC, can take no actions, attackers +2 to attack victim.
• Duration: d4 rounds.

Eye
• Requirement: BAB +10 or greater
• Effect: 1d6 damage. -4 to all Dex-based checks. Two such injuries = blindness.
• Duration: d6 hours, eye loss possibly permanent (DC 15 Fort to avoid)

Called shots only work against the same sorts of targets that Critical Hits are Effective against. The effects of these can be negated early with the use of Cure spells or Healing checks. (Unless referring to permanent eye loss, which would require regeneration.
Also: There are variant rules for monks that cause similar effects in combat. They are different in that they require Stunning Attacks instead of critical hits (so are more controllable) and allow Fort Save. Also, they can be targeted against more body locations.
Use of those rules for “Pressure Point Attacks” doesn’t mean that monks cannot also use this rule when they score a threat.