Honan Intraocular Pressure Reducer Research Articles

Retrobulbar Hemodynamics Before and After Oculopression With and Without Dorzolamide

Purpose: To investigate the effect of intraocular pressure (IOP) reduction by oculopression and topical dorzolamide on retrobulbar hemodynamics.Methods: Sixty patients (70 ± 8.5) solely with cataract diagnosis solely were included in this prospective study. Patients with other systemic and ocular diseases affecting ocular circulation were excluded. On 30 patients (71 ± 8.5), solely oculopression (Honan IOP reducer) was performed. The other half of the patients (69 ± 8.3) additionally received 2 h prior to oculopression additionally topical dorzolamide. Before and after oculopression, IOP was measured and color Doppler imaging (CDI) was performed for the ophthalmic artery (OA), the central retinal artery, and the short posterior ciliary arteries (PCA). Furthermore, blood pressure and heart rate were monitored.Results: At baseline there was no significant IOP difference between both groups (p = 0.54). IOP, measured prior to oculopression, was significant lower (p < 0.0001) in the group treated with dorzolamide (15.2 mmHg) compared to the other group (17.8 mmHg). Oculopression then led to a significant IOP reduction in all patients (p < 0.0001). There was no significant difference of the delta of IOP reduction between both groups observed (p = 0.47).In either group CDI showed a significant increase of peak systolic velocity (PSV) (p < 0.0001) and end-diastolic velocity (EDV) (p < 0.0001) after oculopression in all vessels. In both groups ocular perfusion pressure increased significantly by 6% (p < 0.0001).After oculopression the PSV of the OA was significantly higher (14%; p < 0.0001) after dorzolamide application than after oculopression alone. Furthermore, in the group with oculopression and dorzolamide treatment EDV of the PCA was significantly higher (21%; p < 0.0001) and resistive index of the PCA was significantly lower (−5.6%; p = 0.001).Conclusion: IOP reduction by a pure mechanical procedure like oculopression leads to a significant increase of flow velocities of the retrobulbar vessels. This effect can significantly be increased by using dorzolamide prior to oculopression.

Effect of the Honan Intraocular Pressure Reducer to Prevent Vitreous Reflux after Intravitreal Bevacizumab Injection

To evaluate the effect of the Honan intraocular pressure reducer (HIPR) on vitreous reflux during intravitreal (IVT) injection. Prospective, comparative, controlled, investigator-blinded, randomized clinical study. Sixty eyes of 60 patients who underwent IVT injection were allocated into 2 groups with or without using the HIPR. Vitreous reflux was estimated by measuring largest diameter of the conjunctival bleb formed after IVT injection. Preoperative intraocular pressure (IOP) before and after application of the HIPR and IOP immediately postoperatively and 3 and 10 minutes postoperatively were evaluated. The mean amount of vitreous reflux was significantly less with the HIPR than without the HIPR (1.46±1.04 mm vs 2.61±1.37 mm; p<0.001). The preoperative IOP was significantly lower with the HIPR than without the HIPR (11.62±4.04 mmHg vs 16.26±3.86 mmHg; p=0.026). The 3-minute postoperative IOP was 31.34±3.16 mmHg with the HIPR and 32.61±5.62 mmHg without the HIPR (no statistical significance; p=0.345). The HIPR prevents vitreous reflux after IVT through a reduction in the preoperative IOP. However, the HIPR appears not to affect the postoperative course of transient IOP elevation.

Effect of the Honan intraocular pressure reducer on intraocular pressure increase following intravitreal injection using the tunneled scleral technique

To determine the effect of the Honan intraocular pressure reducer (HIPR) on the rise in intraocular pressure (IOP) after an intravitreal injection using a tunneled scleral incision. This was a prospective, comparative, controlled, non-randomized clinical study. Sixty eyes of 60 patients who received intravitreal injections with the tunneled scleral technique were allocated into two groups, one with and one without application of the HIPR. The pre-operative IOP both before and after application of the HIPR, and the IOP immediately postoperative, and at 3 and 10 min postoperatively were evaluated. The vitreous reflux was estimated by measuring the large diameter of the sub-conjunctival bleb formed after intravitreal injection. The pre-operative IOP in the HIPR group was significantly lower than that in the non-HIPR group following application of the HIPR. The immediate postoperative IOP was significantly lower in the HIPR group than in the non-HIPR group. The IOP at 10 min postoperatively was lower in the HIPR group than in the non-HIPR group. There was no difference in the amount of vitreous reflux between the HIPR and the non-HIPR groups. The use of the HIPR reduces the IOP after an intravitreal injection using the tunneled scleral technique. However, the HIPR does not appear to affect a reduction in the vitreous reflux.

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.

Necessity of the Honan intraocular pressure reducer in cataract surgery using topical anesthesia

Purpose: To assess the use of the Honan intraocular pressure reducer (HIPR) forclear corneal cataract surgery using topical anesthesia. Setting: University of North Carolina Hospitals Ambulatory Care Clinic outpatientoperating rooms. Methods: Of 51 consecutive candidates for surgery (excluding those with uncontrolled glaucoma), 26 were randomly assigned, to' wear the HIPR (Honan group) for 10 minutes before surgery. The remainder were placed in a control group. Intraocular pressure (IOP) was measured before (T1) and after (T2) HIPR application and after patient preparation for surgery (T3). Results: Mean IOP was the same in the Honan and control groups at T1 and T3. AtT2, the groups had a significantly different mean IOP ( P = 1.8 × 10 −5). In the Honan group, mean IOP decreased significantly ( P = 2.8 × 10 −7) between T1 and T2, and there was a significant correlation among patients at T1 and T2 ( P < .0005). Between T2 and T3; the Honan group experienced a significant recovery ( P = 3.5 × 10 −9); there was a significant correlation between the decreases from T1 to T2 and the increases from T2 to T3 ( P < .0005). Mean IOP in the control group did not change between T1 and T2 but increased: significantly between T2 and T3 ( P = .004). Conclusion: When using topical anesthesia, the HIPR transiently reduced IOP. However, the IOP-reducing effect resolved by 'the time of surgery; negating any reason to use the HIPR with topical anesthesia for cataract surgery.

The Effect of External Ocular Compression on Intraocular Pressure Following Retrobulbar Anesthesia

Thirty consecutive patients scheduled for cataract surgery were randomized to external compression with the Honan intraocular pressure (IOP) reducer or digital pressure. The average increase in IOP after retrobulbar injection of 4 ml of anesthetic was 6.20 mm Hg. This increase was followed by a rapid decline in IOP within the first 2 1/2 minutes, averaging 1.20 mm Hg +/- 0.70 below baseline level for the Honan group and 1.00 mm Hg +/- 0.96 below baseline level for the digital group. From 5 to 10 minutes after injection there was a more gradual decline in IOP that averaged 0.35 mm Hg/min in the Honan group and 0.36 mm Hg/min in the digital group. After 10 minutes of external compression the IOP was 5.73 mm Hg +/- 0.96 below baseline level in the Honan group and 4.67 mm Hg +/- 0.64 below baseline level in the digital group. No statistical difference between the IOP measurements of the two groups was observed at 2 1/2 minutes at 5 minutes, or at 10 minutes.

Effect of honan intraocular pressure reducer on ocular and optic nerve blood flow in phakic rabbit eyes

The Honan Intraocular Pressure Reducer (HIPR) was applied to rabbit eyes for 30 min at pressure settings of 0, 30, 50, or 100 mmHg. Ocular blood flow was measured using (85Sr) radioactively labelled 15 micron microspheres either with the HIPR applied to the eye or 15 min after removal. Intraocular pressure was measured before applying the HIPR, immediately after removal, or 15 min after removal. At all pressure settings, the HIPR significantly lowered the IOP (P less than or equal to 0.05) both immediately and 15 min after removal. At all pressure settings, except 0 mmHg, blood flow was significantly (P less than or equal to 0.05) both immediately and 15 min after removal. At all pressure settings, except 0 mmHg, blood flow was significantly (P less than or equal to 0.05) lower with the HIPR applied compared to 15 min after removal.

The interrelationship between intraocular pressure and Honan Intraocular Pressure Reducer pressure.

The relationship between the pressure applied to the enucleated human eye using the Honan Intraocular Pressure Reducer (HIPR) and the peak intraocular pressure as a function of initial intraocular pressure has been examined. The peak intraocular pressure is linearly related to the applied HIPR pressure whether the latter is 30, 50, or 75 mm Hg. The slopes relating peak intraocular pressure to initial intraocular pressure at different HIPR settings are parallel. Use of the HIPR at settings greater than 30 mm Hg and an initial IOP of greater than 30 mm Hg could compromise ocular vascular perfusion.

Effect of Applying the Honan Intraocular Pressure Reducer Before Cataract Surgery

We studied 48 patients undergoing cataract extraction with local anesthesia. In 41 patients, after administering the retrobulbar injection, we applied the Honan intraocular pressure reducer for seven to ten minutes at a pressure setting of 30 mm Hg. Of these 41 patients, 13 received 3-ml injections, 14 received 4-ml injections, and 14 received 5-ml injections. No differences in intraocular pressure related to the quantity of retrobulbar injection were noted. After retrobulbar injection, the mean intraocular pressure for the study population as a whole increased 4.4 mm Hg; after application of the Honan device, it decreased 6.2 mm Hg. In a control group of seven patients, who received 4-ml retrobulbar injections but no applications of the Honan device, mean intraocular pressure increased 6.1 mm Hg immediately after retrobulbar injection and decreased only 0.7 mm Hg after seven to ten minutes.

Effect of Ocular Compression on Intraocular Pressure

A prospective double-blind controlled study was undertaken to determine the effects of different compression times applied to soften the eye on normal subjects. Application of the Honan intraocular pressure reducer (HIPR) produced a significantly (p less than 0.02) greater decrease in intraocular pressure when applied for 40 minutes (14.3 mmHg SD = 1.7) when compared to a five-minute application (8.8 mmHg SD = 1.7). No untoward effects were noted in these patients. Physiologic effects of external ocular compression are discussed.

The Honan intraocular pressure reducer. An experimental study.

Although use of the Honan intraocular pressure reducer is believed to be clinically safe and effective in reducing IOP and the risk of vitreous loss, the IOPs achieved during application of the device have not been directly measured. Intraocular pressure dynamics in ten eyes of five patients were measured shortly after death, using a pressure transducer within the anterior chamber as the Honan device was applied. Pressures were measured again after enucleation. The peak IOPs produced in eyes in situ were much lower than in the same eyes after enucleation. The peak IOP increased as the initial IOP was raised. The Honan device would appear to be safe for eyes undergoing routine anterior segment surgery, but the pressures that may be generated in hypertensive eyes (IOP greater than or equal to 35 mm Hg) might put these eyes at risk for vascular occlusion.

Preoperative use of the Honan Intraocular Pressure Reducer

After administering a retrobulbar injection of anesthesia, we applied the Honan intraocular pressure reducer at a pressure of 30 mm Hg for five minutes to 48 nonglaucomatous eyes and eight glaucomatous eyes undergoing cataract extraction. This technique resulted in mean intraocular pressure reductions of 6.52 mm Hg in the nonglaucomatous eyes (P less than .001) and 10.13 mm Hg (P = .013) in the glaucomatous eyes. These results were comparable to those achieved by using the same device for 40 or more minutes.

Use of the Honan Intraocular Pressure Reducer at The Wilmer Institute

Our technique for the preparation of the patient for cataract surgery is discussed, with description of our use of the Honan intraocular pressure reducer (HIPR). Results of preoperative use of the HIPR in a prospective study of 21 patients and our retrospective experience with over 1,000 patients undergoing cataract surgery (with or without lens implantation) are discussed. The HIPR appears to be a safe and effective means of reducing intraocular pressure preoperatively when used with due care.

An evaluation of the Honan intraocular pressure reducer.

An evaluation of the Honan intraocular pressure reducer.