The scleral buckle surgery is an effective way in treating retinal detachment (RD) patients. Retrobulbar block has been proved effective in scleral buckle surgery. Though retrobulbar anesthesia saves operative time and money compared to general analgesia, the intraoperative pain is frequent and a proportion of postoperative pain is often ignored. Ketorolac has been demonstrated to be a preemptive analgesia in other diseases such as adenotonsillectomy, posterior lumbar spinal fusion, laser-assisted subepithelial keratectomy (LASEK), and so forth. The aim of the investigators study is to determine the safety and preemptive analgesic effect of ketorolac in the perioperative pain control of patients undergoing RD surgery under retrobulbar anesthesia.

Inclusion Criteria:

1. consent of the patient or legal guardian
2. 18 years or above
3. normal height and weight
4. ASA class I, II
5. elective surgery
6. surgery time within 60min
7. understanding of the verbal numerical rating score (0-10)

Exclusion Criteria:

1. history of ocular surgery, trauma or infection
2. intraoperative complications
3. glaucoma or ocular hypertension (> 20 mmHg)
4. diabetic retinopathy
5. diagnosis of asthma or coagulopathy
6. chronic pain syndromes
7. history of peptic ulceration, liver or hematologic disease
8. history of chronic use of analgesics, sedatives, opioids or steroids
9. history of drug or alcohol abuse
10. history of systemic disease
11. sexually transmitted disease (STD)
12. Pregnancy, lactation;
13. cognitive impairment or psychiatric illness;