Proof that the ciliary epithelium can regenerate

Efficacy of Micropulse Laser Cyclophotocoagulation Therapy in Primary Angle Closure Glaucoma

PRCIS

In primary angle closure glaucoma (PACG), micropulse cyclophotocoagulation resulted in a significant reduction in intraocular pressure (IOP), and the number of antiglaucoma medications without any sight-threatening complications. However, the IOP lowering efficacy decreased over time.

PURPOSE

The purpose of this study was to evaluate the efficacy and safety of micropulse trans-scleral cyclophotocoagulation (MP-TSCPC) in PACG.

PATIENTS AND METHODS

Thirty-three phakic PACG eyes with patent laser peripheral iridotomy and IOP uncontrolled on maximum tolerable antiglaucoma medications (AGMs), scheduled for trabeculectomy, were given a trial of MP-TSCPC (810 nm laser, 2000 mw power for 180 seconds, 360 degrees). The primary outcome measure was a success at 1 year with IOP ≤18 mm Hg and ≤15 mm Hg with (qualified success) or without (absolute success) AGMs after a single session of MP laser. Secondary outcome measures were changes in pupillary diameter, visual acuity, central macular thickness, and subjective pain perception.

RESULTS

Thirty-two out of 33 PACG patients completed 12 months of follow-up. The mean age of patients was 54.7±8.9 years; male:female ratio was 1:1. The baseline IOP was 25.7±5.3 mm Hg, which reduced to 17.9±4.6 mm Hg at the end of 12 months (P<0.0001). Twenty eyes (62.5%) achieved qualified success, and 1 eye (3.125%) had absolute success at 12 months for IOP ≤18 mm Hg; 6 eyes (18.75%) had qualified success, and 1 eye (3.125%) had absolute success for IOP ≤15 mm Hg at 12 months follow-up. A significant reduction was also observed in the number of AGMs (4.4±0.8 at baseline to 2.9±1.1 at 12 months; P <0.0001). Five eyes (15.6%) received additional treatment-3 eyes (9.4%) requiring a subsequent filtering procedure, and 2 eyes (6.2%) requiring an additional MP-TSCPC session. No significant change in pupillary diameter (P=0.489) or central macular thickness (P=0.938) was noted at 12 months. There was a transient drop of visual acuity >2 lines in 1 patient due to cystoid macular edema, and no major postlaser complications were noted.

CONCLUSIONS

MP-TSCPC can be used as an interim procedure to reduce IOP in PACG eyes and delay the need for invasive surgery. Most patients require continued use of glaucoma medications, and target IOPs achieved are in the high teens.

Efficacy and safety of ultrasound cycloplasty in Indian eyes with open-angle glaucoma

Purpose

To evaluate the safety and efficacy of ultrasound cycloplasty in eyes with primary or secondary open-angle glaucoma, not amenable to adequate control of intra-ocular pressure (IOP) with medical treatment.

Methods

Prospective interventional cohort study of 28 eyes of 28 subjects in a tertiary eye care centre in India in patients with open-angle glaucoma. All enrolled eyes underwent ultrasound cycloplasty with the second-generation probe with six shots of 8 s each, operated by a single surgeon between November 2018 and January 2020. They were followed up for a period of 12 months. The primary treatment outcome was IOP and the secondary outcomes were vision and postoperative complications.

Results

A total of 28 eyes of 28 patients were studied, and the mean age was 63.82 ± 6.46 years. Primary open-angle glaucoma (75%) was the most common etiology. There was significant reduction in IOP from the baseline (24.93 ± 4.27 mmHg) to the postoperative value (15.82 ± 3.14 mmHg) at the end of 12 months (P < 0.00001). Mean reduction in IOP was 9.14 ± 4.09 mmHg at 12 months (36.66%). Number of ocular hypotensives reduced significantly from baseline (3.32 ± 0.47) to 12-month postoperative follow-up (0.68 ± 0.74) (P < 0.00001). Qualified success was achieved in 89.28% eyes. No major complications were noted.

Conclusion

Ultrasound cycloplasty is found to be effective and safe in eyes with open-angle glaucoma because of the primary or secondary etiology, being more effective in the former.

Efficacy and Safety of Micropulse Transscleral Cyclophotocoagulation

Background: Early studies have shown that micropulse transscleral cyclophotocoagulation (MP-TSCPC) might be an effective and safe treatment option for lowering intraocular pressure (IOP). These studies were, however, somewhat limited, in particular by their retrospective nature and the length of follow-up. Therefore, we assessed the efficacy and safety of this novel treatment in a large cohort for up to 4 years. Methods: We performed a prospective cohort study, including all patients who were treated with MP-TSCPC since November 2017. The primary outcome was a reduction of IOP and the number of IOP-lowering medications. Results: The mean ± standard deviation baseline IOP and number of IOP-lowering medications were 26.6 ± 10.8 mmHg and 3.3 ± 1.3. IOP was reduced by 8.2 ± 7.9 (31.8% reduction), 6.9 ± 8.7 (28.1% reduction), and 7.1 ± 8.4 (30.2% reduction) mmHg after 6, 12, and 24 months, respectively (p < 0.001). The mean postoperative number of IOP-lowering medications was significantly reduced after 6 months by 0.6 ± 1.5 (p = 0.002) but was not significantly different after 12 or 24 months. Oral acetazolamide was significantly reduced from 28 (29%) eyes before treatment, to 9 (9%) at the last follow-up visit (p < 0.001). No major complications were observed after treatment. Conclusions: MP-TSCPC is a safe and effective treatment option for lowering IOP, but only reduced IOP-lowering medications in the first 6 months after treatment. However, MP-TSCPC is especially effective in getting patients off oral IOP-lowering drugs.

Micropulse Transscleral Cyclophotocoagulation as Primary Surgical Treatment for Primary Open Angle Glaucoma in Taiwan during the COVID-19 Pandemic

Glaucoma is the leading cause of irreversible blindness worldwide, with primary open angle glaucoma (POAG) accounting for the greatest number of total glaucoma cases. This study aimed to evaluate the efficacy and safety of micropulse transscleral cyclophotocoagulation (MP-TSCPC) as a primary procedure in POAG during the COVID-19 pandemic. We retrospectively analyzed 60 eyes of 52 patients, who were diagnosed with mild-to-end-stage POAG without previous glaucoma surgery and received MP-TSCPC between 1 January 2020 and 31 August 2020. The mean preoperative intraocular pressure (IOP) significantly decreased from 27.8 mm Hg to 19.8, 20.1, 20.3, 20.4, and 20.2 mm Hg at 1, 3, 6, 9, and 12 months, respectively (all p < 0.05). The mean number of IOP-lowering medications used significantly decreased from 3.3 at the baseline to 1.6, 1.8, 1.8, 1.9, and 1.9 at 1, 3, 6, 9, and 12 months, respectively (all p < 0.001). Total withdrawal of antiglaucoma medications was fulfilled in five patients. The main outcome was achieved in 81.7% at postoperative month 12. The most common adverse effect was transient mydriasis (28.3%). No major complications were encountered. MP-TSCPC seems to be an effective and safe treatment to reduce IOP and the medication burden with minimal vision-threatening complications in mild-to-end-stage POAG patients without previous glaucoma surgery.

A 2-year prospective multicenter study of ultrasound cyclo plasty for glaucoma

Ultrasound cyclo plasty (UCP) is a recently developed surgical technique for glaucoma allowing a selective and controlled coagulation of the ciliary body. We herein investigated the long-term efficacy and safety of UCP for the treatment of glaucoma. This prospective study included patients with primary and secondary glaucoma. All surgeries were performed using the EyeOP1 device (Eye Tech Care, Rillieux-la-Pape, France). Sixty-six patients were included, and 60 completed regularly the 2-year follow-up. Preoperative IOP was 28.5 ± 9.6 mmHg and significantly decreased to 17.0 ± 5.4 at 2 years (p < 0.001). The daily number of both hypotensive eye drops and acetazolamide tablets decreased significantly (respectively, from 2.6 ± 1.1 to 1.7 ± 1.2 and from 0.7 ± 0.8 to 0.2 ± 0.5; both p < 0.001). At 2 years, 68.1% of patients met the definition of qualified success (IOP < 21 mmHg regardless of glaucoma medications) and 10.3% of patients met the definition of complete success (IOP < 21 mmHg without glaucoma medications). No major intra- or postoperative complications occurred; however, 15 eyes required additional glaucoma surgery. These results suggest that UCP is an effective and safe procedure to reduce IOP in glaucoma patients through a 2-year follow-up period.

Efficacy and safety of high-dose ultrasound cyclo-plasty procedure in refractory glaucoma

AIM

To evaluate the efficacy and safety of high-dose ultrasound cyclo-plasty (UCP) for the treatment of refractory glaucoma in Chinese patients.

METHODS

In this 6-month retrospective study, 37 eyes of 37 patients suffering from severe glaucoma with uncontrolled intraocular pressure (IOP) of ≥21 mm Hg underwent 8-s ultrasonic cyclocoagulation with ten active piezoelectric elements. A complete ophthalmic examination was performed before and at 1d, 1, 3, 6mo after UCP. Therapeutic success was defined as IOP reduction from baseline ≥20% and IOP ≥5 mm Hg without adding new glaucoma medication compare to baseline at the 6-month follow-up visit. In addition to mean IOP at each follow-up visit, medications used and complications were also detected and compared to baseline.

RESULTS

After UCP procedure, the mean IOP was significantly reduced (P<0.01) from the preoperative 44.1±11.9 mm Hg to postoperative 26.7±11.8 mm Hg at 3mo, and 30.4±14.5 mm Hg at 6mo. The overall mean IOP reductions achieved at 3 and 6mo were 39% and 31% compared to baseline IOP. Sixty-one percent of patients responded well to UCP treatment with a mean IOP reduction of 48% at 3mo and 42% at 6mo. Ocular pain in most of patients were alleviated. No serious intraoperative or postoperative complications occurred.

CONCLUSION

High-dose UCP treatment is an effective and safe procedure to reduce IOP in Chinese patients with severe glaucoma.

The outcome of transscleral cyclophotocoagulation for the management of acute angle closure

PURPOSE

To investigate the outcome of transscleral cyclophotocoagulation (TCP) in the treatment of acute angle closure (AAC) refractory to medical treatment.

METHODS

This is a retrospective interventional case series. The inclusion criteria include patients diagnosed with AAC who had TCP. Pre-TCP and post-TCP intraocular pressure (IOP), visual acuity, and AAC treatment were analyzed. The complications and the results of subsequent treatments including lens extraction if performed were also assessed.

RESULTS

Thirteen eyes (13 patients) met the study criteria. The median time to TCP from presentation was 5 days (range 3-30 days). The mean presenting IOP was 56 ± 6 mm Hg (range 48-70 mm Hg) and the medically treated mean IOP before TCP was 40 ± 5 mm Hg (range 34-52 mm Hg). All patients (100%) responded to TCP. The mean post-TCP IOP at day 1 and months 1, 3, 6, 12, and 24 were 19, 23, 19, 19, 18, and 17 mm Hg. There was 1 case of hyphema post-TCP. Lens extraction ± goniosynechialysis was performed in 10 patients (77%) from 1 month post-TCP onwards. The mean IOP prior to lens extraction was 26 mm Hg (range 19-32 mm Hg). The mean IOP 3 months after lens extraction was 15 mm Hg (range 8-19 mm Hg). The mean number of topical IOP-lowering medications 12 months post-TCP was 1.1.

CONCLUSIONS

Transscleral cyclophotocoagulation is effective and safe in reducing IOP in patients with AAC refractory to medical and laser peripheral iridotomy treatments. We advocate that TCP should be considered early in the management of AAC refractory to medical treatment to avoid irreversible optic neuropathy.

Cell turnover in ciliary epithelium compared to other slow renewing epithelia in the adult mouse

Adult albino mice received tritiated thymidine either injected subcutaneously (333 microCi) every 6 hours for up to 36 hours, or administered in their drinking water for up to 74 days (about 45 microCi/day). Tissue sections were examined with autoradiography to determine the distribution of the label. Animals receiving subcutaneous injections showed no labeled cells in the choroid plexus epithelium and only one cell of 6600 cells counted in the ciliary epithelium was labeled. Animals exposed to the isotope in their drinking water for 74 days showed considerable uptake of label in hepatocytes (15%) and cortical kidney tubules (17%), whereas ciliary and choroid epithelia showed very low uptake at 0.25% and 0.01%, respectively. The data show that the ciliary and choroid epithelia have a very slow turnover rate compared to other slow renewing tissues, and, under normal conditions, these tissues are not renewed in the animal's adult life span.

Effects of water-soluble marihuana-derived material (MDM) on the rabbit ciliary body: light and electron microscopy

The response of the ciliary processes of the rabbit eye to water-soluble marihuana-derived material (MDM) has been examined with light and electron microscopy. Following intravenous injection of MDM, the processes undergo considerable swelling within 1 hour followed by thrombus formation in the capillaries and extravasation of red cells. Later phases include the formation of cysts between the non-pigmented and pigmented cell layers of the ciliary epithelium. The ciliary process edema coincides with the initial hypertensive phase seen after intravenous MDM, while the hematogenous response coincides with the fall in intraocular pressure. Following intravitreal injection of MDM, a similar pattern of structural changes occurs that accompanies a fall in intraocular pressure that lasts for several days; because the physiological response occurs over a longer time course (14-20 hours) relative to intravenous administration where the intraocular pressure changes occur rapidly, the ciliary process swelling phase does not result in an increase in intraocular pressure. The physiologic changes in the eye caused by MDM appear to be related to the induction of a general inflammatory response in the ciliary processes, with a primary effect on the vascular system.

An indwelling cannula system for the primate eye

An indwelling cannula system was designed as an instrument for chronic drug infusion into the vitreous cavity and tested in the cynomolgus monkey eye with repeated injections or continuous infusion using a pumping device. The cannula was passed through the pars plana and its tip situated in the vitreous cavity close to the macular area. Clinical observations up to 18 months did not reveal any adverse effects due to implantation. Histopathological observations from 1 week to 18 months after surgery revealed tissue proliferation around the cannula was minimal and localized only at the wound site, where proliferative tissue originated from the episclera and ciliary epithelium. Retina and choroid at the posterior pole showed normal morphology. Light microscopic autoradiograms demonstrated the function of this system. Injections of tritiated leucine through the cannula resulted in narrow bands of radioactive labelling of the photoreceptor outer segments corresponding to each injection. In contrast, chronic delivery using the pumping device resulted in a diffuse and wide band of labelling. These results strongly suggest that this system did not adversely affect the eye and that repeated intravitreal injections or chronic drug delivery into the vitreous are feasible using this system. Furthermore, autoradiographic results suggest that the drugs infused into the vitreous cavity spread readily into the retina.

[Experimental and clinical examinations of the effect of cryosurgery of intraocular pressure]

Diathermy and cryosurgery have different effects on living tissue. Cell membranes are ruptured by cryosurgery, but the proteins are less affected than by diathermy. A short review of experimental cyclocryosurgery and the clinical results are presented. Data from the literature as well as evaluation of patients confirm that, as yet, the results are not satisfactory. The sequelae of freezing are very different in slow-and fast-freezing procedures. Therefore, the results in rabbits treated with a cryosurgical unit used for retinal detachment surgery (Amoils, -80 degrees C) were compared with the results using a cryoprobe cooled with liquid nitrogen (-180 degrees C). A permanent reduction in intraocular pressure was not achieved using cyclocryotherapy applied with the equipment used for detachment surgery (-80 degrees C). Repeated cryosurgery of this type did not result in a permanent pressure reduction. Histopathology demonstrated that the ciliary epithelium had regenerated and prolongation of the cyclocryotherapy applications did not result in a permanent intraocular pressure reduction. Lens opacities occurred in all rabbits of this series. Application of cryotherapy with a nitrogen-cooled cryoprobe (2.5 mm2 contact area) caused severe damage, resulting in phthisis bulbi. Another nitrogen-cooled probe (contact area of about 1 mm2 diameter) resulted in a permanent reduction in intraocular pressure, but the anterior parts of the lens became opaque. Histopathology revealed total necrosis of the ciliary epithelium and the basal membrane. Three months after cyclocryotherapy of this type the ciliary processes were atrophic and covered with connective tissue and regeneration of epithelial cells was not found in areas of such cryotherapy scars. Further experiments have been commenced including a reduction of application time, in order to find the optimum application technique resulting in permanent intraocular pressure reduction and the fewest possible side effects.