The effect of therapeutic ultrasound on the average of multiple intraocular pressures throughout the day in therapy-resistant glaucoma

Ultrasound Cyclo Plasty in Glaucoma: Two-Year Outcomes

PURPOSE

To evaluate the two-year outcomes of Ultrasound Cyclo Plasty (UCP) in uncontrolled glaucoma.

METHODS

A retrospective cohort study included patients with uncontrolled primary or secondary glaucoma who underwent UCP at King Abdul Aziz University Hospital, Riyadh, Saudi Arabia between 2016 and 2021. The main outcome measures were: intraocular pressure (IOP), number of antiglaucoma medications, and presence of vision-threatening complications. The surgical outcome of each eye was classified as complete success, qualified success, or failure, based on the main outcome measures.

RESULTS

One hundred and eighty-two eyes of 158 patients were included in the study. The mean follow-up period was 29.71 months (±18.1). The IOP and number of antiglaucoma medications decreased significantly from a mean of 23.46 mm Hg (±6.3) and 3.33 (±0.9) to 17.33 (±7.1) and 2.14 (±1.4), and 16.24 (±6.3) and 1.90 (±1.5) on the 12th and 24th months respectively. The overall success rates were 78.0% (143/182) and 85.6% (95/111), and the failure rates were 21.4% (39/182) and 14.4% (16/111) on the 12th and 24th months respectively. The most common complications were cataract development/progression and anterior chamber reaction.

CONCLUSIONS

UCP offers a reasonable IOP control and reduction of the antiglaucoma medications burden.

Ultrasound Cyclo Plasty for Treatment of Surgery-Naïve Open-Angle Glaucoma Patients: A Prospective, Multicenter, 2-Year Follow-Up Trial

Background: The purpose of this prospective study was to evaluate the efficacy and safety of the Ultrasound Cyclo Plasty (UCP) procedure using high-intensity focused ultrasound in surgery-naïve open-angle glaucoma patients. Methods: prospective, non-randomized, single-arm, multicenter clinical trial. Sixty-six eyes with primary open-angle glaucoma, intraocular pressure (IOP) ≥21 mmHg and with no history of filtering surgery were enrolled. Patients were treated by UCP with a therapy probe comprising six piezoelectric transducers, consecutively activated for 8 s each. Complete ophthalmic examination was performed before the procedure, 1 day after the procedure, and 1, 3, 6, 12, 18 and 24 months after the procedure. Primary outcomes were complete success (defined as IOP lowering from baseline ≥20% without additional glaucoma medications) and vision-threatening complications. Secondary outcomes were the presence of complications and the reduction of the number of medications used. Results: IOP was significantly reduced after one procedure (p < 0.05), from a mean pre-operative value of 24.3 ± 2.9 mmHg (n = 2.3 hypotensive medications) to a mean value of 15.9 ± 3.6 mmHg (n = 2.2 hypotensive medications) at 2 years (mean IOP lowering of 33%). Surgical success was achieved in 74% of eyes. Notwithstanding side effects such as transient anterior chamber inflammation, refractive error changes, transient hypotony and macular edema, no major intra or post-operative complications such as phthisis, induced cataract, neovascularization or significant vision loss were observed. Conclusions: Ultrasound Cyclo Plasty is a valuable, effective and well-tolerated procedure to lower IOP in patients with open-angle glaucoma without previous filtering surgery.

The Effect of High-Intensity Focused Ultrasound on Aqueous Humor Dynamics in Patients with Glaucoma

PURPOSE

To investigate the effects of high-intensity focused ultrasound (HiFU) on aqueous humor dynamics in patients with glaucoma.

DESIGN

Comparative, nonrandomized, interventional study.

PARTICIPANTS

Adult patients with a diagnosis of open-angle glaucoma or ocular hypertension with suboptimal intraocular pressure (IOP) control despite maximum medical treatment who required further IOP optimization.

METHODS

All patients underwent comprehensive ophthalmic examination before aqueous humor dynamics study measurements, including fluorophotometry and digital Schiøtz tonography. All patients received 6 seconds of HiFU therapy. Aqueous humor dynamics studies were repeated 3 months after the treatment (patients had 4-week washout from their glaucoma medication before their aqueous humor dynamics study measurements at baseline and the 3-month visit).

MAIN OUTCOME MEASURES

Intraocular pressure, facility of topographic outflow, aqueous flow rate, and uveoscleral outflow.

RESULTS

Thirty eyes of 30 patients were included in the study. At the 3-month postoperative visit, the mean postwashout IOP was reduced by 16% (31.7±5.3 vs. 26.6±4.8 mmHg, P = 0.004), and aqueous flow rate was decreased by 15% (2.07±0.73 vs. 1.77±0.55 μl/min, P = 0.05) from baseline. Neither the tonographic outflow facility nor the uveoscleral outflow was significantly different from baseline. There is a 20% risk of treatment failure (those who needed further glaucoma surgical intervention) within 1 month after a single HiFU treatment (n = 6). Only 25 patients (80%) were able to undergo post-treatment washout measurements, and in these eyes, only 26.6% of eyes achieved >20% IOP reduction at 3 months compared with baseline.

CONCLUSIONS

We investigated the aqueous humor dynamics effects of a cyclodestructive procedure and specifically HiFU in patients with uncontrolled open-angle glaucoma on maximum tolerated medical therapy. High-intensity focused ultrasound reduced IOP 3 months postoperatively by 16% and aqueous flow decreased by 15% without any significant effect on tonographic outflow facility and uveoscleral outflow.

Efficacy and safety of ultrasonic circular cyclocoagulation with second-generation probe in glaucoma: A retrospective study

Background

To assess the efficacy and safety of the second-generation probe of ultrasonic circular cyclocoagulation (UC3) in naive or refractory glaucoma, with a 6-month follow-up.

Methods

A retrospective consecutive case-series study included patients having a UC3 procedure with the second-generation probe of the EyeOP1 device, intraocular pressure (IOP) ≥ 21 mmHg and under maximum tolerated medical treatment, with or without previous glaucoma surgery. Surgical success was defined at the 6-month post-operative visit as IOP > 5 and ≤ 21 mmHg with IOP reduction ≥ 20% from baseline, without any reoperation, and visual acuity better than negative light perception.

Results

100 patients were included and 97 (97.0%; 97 eyes) attended the 6-month follow-up. At 6 months, surgical success was obtained in 48 eyes (49.5%). Intraocular pressure was reduced from a mean ± SD preoperative value of 28.0 ± 5.6 mmHg to 19.3 ± 7.1 mmHg at 6 months (p<0.0001). The proportion of eyes requiring oral acetazolamide decreased from 57.0% to 30.0% between baseline and 6 months after surgery (p = 0.0007). We observed 15 (15.0%) cases of postsurgical macular edema, 8 (8.0%) of hypotony, and 20 (20.0%) of visual acuity loss > 2 Snellen lines. Postsurgical macular edema was associated with a history of epiretinal membranes, uveitis or retinal detachment. Risk factors for hypotony were a history of diabetes or trabeculectomy.

Conclusions

The second-generation UC3 probe significantly reduced IOP in eyes with naive and refractory glaucoma but severe post-operative complications were often observed. Further studies are needed to better identify responders and decrease the high risk for complications associated with the procedure.

Safety and efficacy of ultrasound ciliary plasty as a primary intervention in glaucoma patients

AIM

To evaluate the safety and the efficacy of the ultrasound ciliary plasty (UCP) on the intraocular pressure (IOP) control in glaucomatous eyes without previous glaucoma surgery.

METHODS

A retrospective study included patients with primary and secondary glaucoma who underwent UCP in Dar AlShifa Hospital, Kuwait between January 2017 to June 2018. High-intensity focused ultrasound procedures were performed under peribulbar anesthesia using the 2^nd generation probe with 8s duration of each of the 6 shots. Complete ophthalmologic examinations were scheduled pre-treatment, and at 1d, 1wk, 1, 3, 6 and 12mo post-treatment. Primary outcomes were the IOP reduction and success rates at 12mo, while the secondary outcomes were the occurrence of vision threatening complications and visual acuity.

RESULTS

The records of 62 eyes of 62 patients were analyzed with mean age of 63.8y (67.7% males). There was statistically significant reduction in the mean IOP from 35.2±8.3 mm Hg before treatment to 20.6±8.7 mm Hg at 12^th month (P<0.0005) with a mean percentage IOP reduction of 42.3% with significant reduction in the mean number of antiglaucomatous drugs from 3.2±0.4 before treatment to 2.1±1.02 at 12mo (P<0.0005). Qualified success was achieved in 77.4% of eyes at 12mo. No major intra- or post-treatment complications were reported.

CONCLUSION

Second-generation UCP prove to be effective in reducing IOP in naive glaucoma patients with lower success rates in cases of neovascular and uveitic glaucomas.

High-Intensity Focused Ultrasound Circular Cyclocoagulation in Glaucoma: A Step Forward for Cyclodestruction?

The ciliary body ablation is still considered as a last resort treatment to reduce the intraocular pressure (IOP) in uncontrolled glaucoma. Several ablation techniques have been proposed over the years, all presenting a high rate of complications, nonselectivity for the target organ, and unpredictable dose-effect relationship. These drawbacks limited the application of cyclodestructive procedures almost exclusively to refractory glaucoma. High-intensity focused ultrasound (HIFU), proposed in the early 1980s and later abandoned because of the complexity and side effects of the procedure, was recently reconsidered in a new approach to destroy the ciliary body. Ultrasound circular cyclocoagulation (UC³), by using miniaturized transducers embedded in a dedicated circular-shaped device, permits to selectively treat the ciliary body in a one-step, computer-assisted, and non-operator-dependent procedure. UC³ shows a high level of safety along with a predictable and sustained IOP reduction in patients with refractory glaucoma. Because of this, the indication of UC³ was recently extended also to naïve-to-surgery patients, thus reconsidering the role and timing of ciliary body ablation in the surgical management of glaucoma. This article provides a review of the most used cycloablative techniques with particular attention to UC³, summarizing the current knowledge about this procedure and future possible developments.

Uveo-scleral outflow pathways after ultrasonic cyclocoagulation in refractory glaucoma: an anterior segment optical coherence tomography and in vivo confocal study

AIMS

To evaluate, using anterior segment optical coherence tomography (AS-OCT) and in vivo confocal microscopy (IVCM), the uveo-scleral aqueous humour (AH) outflow pathways after ultrasonic circular cyclocoagulation (UCCC).

METHODS

Forty-four patients with refractory glaucoma underwent 4 or 6 s UCCC (group 1, 24 eyes; group 2, 20 eyes). UCCC was successful when the preoperative intraocular pressure (IOP) reduced by one-third. AS-OCT and IVCM were performed at baseline and at month 1 to evaluate the sclera and conjunctiva. The main outcomes were mean intra-scleral hyporeflective spaces area (MIHSA: mm²) at AS-OCT, mean density and area of conjunctival microcysts (MMD: cysts/mm²; MMA: µm²) at IVCM. The relations between MIHSA, MMA and MMD with IOP were analysed.

RESULTS

Mean baseline IOP was 26.9±2.8 mm Hg in group 1 and 27.5±4.0 in group 2. Intra-scleral hyporeflective spaces and microcysts were observed in both groups, without significant differences in MIHSA, MMA and MMD. At month 1, UCCC was successful in 63.6% of patients (41.6% in group 1, 80% in group 2), and IOP reduced to 18.8±3.2 (30.1%) and 17.1±2.7 mm Hg (38.7%), respectively (p<0.001). MIHSA showed a twofold and threefold increase in group 1 and 2 (p<0.05), with a significant difference between groups (p<0.05). MMA and MMD increased in both groups (p<0.05), with values higher in group 2 (p<0.05). Significant relations were found between MIHSA and IOP in both groups (p<0.01).

CONCLUSIONS

UCCC induced anatomical modifications of sclera and conjunctiva, which suggested that the trans-scleral AH outflow enhancement is one of the possible mechanisms exploited by ultrasounds to reduce IOP.

Ultrasound-enhanced ocular delivery of dexamethasone sodium phosphate: an in vivo study

BACKGROUND

The eye's unique anatomy and its physiological and anatomical barriers can limit effective drug delivery into the eye.

METHODS

An in vivo study was designed to determine the effectiveness and safety of ultrasound application in enhancing drug delivery in a rabbit model. Permeability of a steroid ophthalmic drug, dexamethasone sodium phosphate, was investigated in ultrasound- and sham-treated cases. For this study, an eye cup filled with dexamethasone sodium phosphate was placed on the cornea. Ultrasound was applied at intensity of 0.8 W/cm(2) and frequency of 400 or 600 kHz for 5 min. The drug concentration in aqueous humor samples, collected 90 min after the treatment, was determined using chromatography methods. Light microscopy observations were done to determine the structural changes in the cornea as a result of ultrasound application.

RESULTS

An increase in drug concentration in aqueous humor samples of 2.8 times (p < 0.05) with ultrasound application at 400 kHz and 2.4 times (p < 0.01) with ultrasound application at 600 kHz was observed as compared to sham-treated samples. Histological analysis showed that the structural changes in the corneas exposed to ultrasound predominantly consisted of minor epithelial disorganization.

CONCLUSIONS

Ultrasound application enhanced the delivery of an anti-inflammatory ocular drug, dexamethasone sodium phosphate, through the cornea in vivo. Ultrasound-enhanced ocular drug delivery appears to be a promising area of research with a potential future application in a clinical setting.

Therapeutic applications of ultrasound in ophthalmology

Therapeutic ultrasound, although less well known than ultrasound for diagnostic imaging, has become a topic of growing interest in ophthalmology. High intensity focused ultrasound (HIFU) for the treatment of glaucoma and ultrasonic drug delivery are the two main areas of research and potential clinical applications. For the treatment of glaucoma, the specific advantage of HIFU, particularly when compared to the laser, is that the energy can be focused through optically opaque media, especially through the sclera which is a strongly light-scattering medium. HIFU is therefore a possible method for partial coagulation of the ciliary body (an anatomical structure responsible for the production of the liquid filling the eye) and, hence, reducing intraocular pressure and the risk of glaucoma. Ocular drug bioavailability also remains a challenge, being limited by multiple barriers to drug entry and lacrimal drainage, and making it difficult to achieve a sufficient drug concentration for numerous diseases of the front and back of the eye. As the front wall of the eye (cornea and anterior sclera) is a pathway for topically applied drugs, locally applied ultrasound has been proposed as a way of enhancing the delivery and activity of drugs and genes. Despite the fact that experimental studies seem to confirm the potential benefit of ultrasound ocular drug delivery, there is still a lack of clinical evidence. The aim of this contribution is to provide an update on recent advances in the field of therapeutic ultrasound in ophthalmology.

Development of a miniaturized HIFU device for glaucoma treatment with conformal coagulation of the ciliary bodies

This study examined the feasibility of high-intensity focused ultrasound (HIFU) for glaucoma treatment with conformal coagulation of the ciliary bodies (CB). A miniaturized high frequency (21 MHz) device was developed, based on the geometry of the eye and adapted to the anatomy of the rabbit eyeball. Six line-focus lesions were distributed along a circle and produced by six cylindrical transducers. To be conformal, the numerical model predicted an intensity of 6.9 W/cm(2), with exposure duration of 3 s ON (powered per sector). In vivo experiments were conducted on two rabbits. A significant intraocular pressure reduction was noted (-45% and -31%). Histology demonstrated conformal and homogeneous coagulation of the CB without side effects.

The effect of high-intensity focused ultrasound on intraocular pressure in therapy-resistant glaucoma 3-4 months and 1 year after treatment

The effect of therapeutic ultrasound for the treatment of refractory glaucoma was evaluated in 44 patients by comparing average IOP curves measured before and 3-4 months after treatment. The insonification regime was standardized and the glaucoma medication in each individual patient was unchanged during IOP curve measurements. The average IOP decrease 3-4 months after insonification was 42.2% +/- SD 31.9. In 23 patients who were followed for at least one year the average IOP 3-4 months after treatment was compared with the average IOP 1 year after treatment. In this group average IOP 3-4 months after treatment was 25.3 mmHg +/- SD 16.4 and average IOP 1 year after treatment was 24.1 mmHg +/- SD 15.9. The correlation coefficient between IOP 3-4 months after treatment and IOP 1 year after treatment was 0.79 (P < 0.0001).

Therapeutic ultrasound for the treatment of glaucoma

A multicenter clinical trial of therapeutic ultrasound for the treatment of glaucoma included 20 centers in the United States in which 1,117 treatments were performed on 880 eyes. The study was limited to patients with refractory glaucoma who had not benefited from conventional medical and surgical techniques. Approximately 782 of 1,117 treatments (70%) showed an initial decrease in intraocular pressure from a pretreatment mean of 38.1 mm Hg to 22 mm Hg or less. By Kaplan-Meier survival analysis, the single treatment success rate (intraocular pressure between 6 and 22 mm Hg) was 48.7% at six months posttreatment. When retreatment was used subsequent to failure, the one-year multitreatment success rate was 79.3%. The most common complications were an immediate posttreatment intraocular pressure increase lasting a few hours and mild iritis. Other complications included scleral thinning in 28 of 1,117 treatments (2.5%) and phthisis bulbi in 12 of 1,117 treatments (1.1%).