Effect of the Honan intraocular pressure reducer in sub-Tenon's anesthesia

Purpose: To ascertain whether the Honan intraocular pressure reducer (HIPR) has an effect on the preoperative intraocular pressure (IOP), surgeon's assessment of anesthesia, and patients' analgesic experience when sub-Tenon's anesthesia is used for routine cataract surgery. Setting: Princess Alexandra Eye Pavilion, Edinburgh, Scotland. Method. Forty-five eyes of 45 patients having routine phacoemulsification cataract surgery were randomized to receive 10 minutes of ocular compression using the HIPR or no compression after administration of sub-Tenon's anesthesia. The IOP was measured immediately before and immediately and 10 minutes after sub-Tenon's anesthesia administration using a standard technique. One surgeon who was masked to the randomization process performed all injections and completed a questionnaire on aspects of the anesthetic block. Patients scored their level of analgesia during surgery. Results: The mean rise in IOP immediately after administration of sub-Tenon's anesthesia was 1.39 mm Hg +/-3.91 (SD) (95% confidence interval +0.22 to 2.57; P=.021). In the 22 patients who received compression, there was a mean IOP reduction of 4.20+/-2.74 mm Hg at 10 minutes. The mean difference between the compression and no-compression groups at 10 minutes was 4.99 mm Hg (P<.0001). There was no difference in the surgeon's scores for any aspect of the sub-Tenon's anesthesia (P>.05). All patients reported good levels of analgesia. Conclusions: There was a significant reduction in IOP after compression using the HIPR. However, the rise in IOP after administration of sub-Tenon's anesthesia was small and the use of the HIPR did not make a significant difference in the effectiveness of the anesthesia to the surgeon or patients.