Surgical stimulation of uveoscleral outflow is an alternative to cyclodestructive procedures

Aim: to assess clinical efficacy and safety of surgical scleral rejection (SSR) vs. transscleral diode laser cyclophotocoagulation (TSCPC) in primary open-angle glaucoma (POAG) and secondary glaucoma (SG). Patients and Methods: study (prospective) group included 84 patients with POAG and SG after SSR. Control (retrospective) group included 80 patients after TSCPC. In addition, the patients were distributed by age and the stage and type of glaucoma, i.e., 128 patients were diagnosed with POAG and 36 patients were diagnosed with secondary thrombotic glaucoma. Follow-up was 24 to 36 months. IOP measurements, tonography (to assess the coefficient outflow facility / COF), ultrasound biomicroscopy of the anterior segment, visual acuity measurement, and visual field testing were performed. Results: no complications after SSR were reported in patients with POAG and SG. In contrast, postoperative complications (choroidal effusion, hyphema, and uveitis) were reported in 14% of patients after TSCPC. Long-term IOP-lowering efficacy of both procedures was similar (87% after SSR and 89% after TSCPC). In POAG, greater IOP reduction was seen after TSCPC (by 39.11%) compared to SSR (by 31.58%) (p<0.05). Meanwhile, in patients with SG, treatment outcomes were similar (IOP reduced by 36.78% after TSCPC and by 35.26% after SSR). In longterm follow-up, PVF reduced by 10.76% vs. baseline after TSCPC but increased by 11.19% vs. baseline after SSR (p≤0.05). Surgery resulted in the improvement or stabilization of visual functions. Ultrasonography has demonstrated that outflow pathways (intrascleral space and filtering bleb) remain functional after SSR in long-term follow-up. Conclusion: SSR is an alternative to cyclodestructive procedures in POAG and SG. Sclera being the final point of the uveoscleral outflow is a perspective entity to develop surgical approaches to glaucoma treatment. Keywords: surgical scleral resection, uveoscleral outflow, sclera, primary open-angle glaucoma, secondary glaucoma, glaucoma surgery, transscleral diode laser cyclophotocoagulation. For citation: Korchuganova E.A., Kazantzeva A.Yu. Surgical stimulation of uveoscleral outflow is an alternative to cyclodestructive procedures. Russian Journal of Clinical Ophthalmology. 2021;21(1):9–13. DOI: 10.32364/2311-7729-2021-21-1-9-13.

Hyperbranched Cationic Glycogen Derivative-Mediated IκBα Gene Silencing Regulates the Uveoscleral Outflow Pathway in Rats

The role of the IκB/NF-κB signaling pathway in the uveoscleral outflow pathway was investigated with IκBα gene silencing mediated by the 3-(dimethylamino)-1-propylamine-conjugated glycogen (DMAPA-Glyp) derivative. The IκBα-siRNA-loaded DMAPA-Glyp complex was transfected into the ciliary muscles of rats by intracameral injection (labeled as the DMAPA-Glyp+siRNA group). The Lipofectamine™ 2000 (Lipo)/siRNA complex and the naked siRNA were set as the controls. The mRNA and protein expression of IκBα, NF-κBp65, and MMP-2 were analyzed by real-time PCR, western blotting, and in situ gelatin zymography. Nuclear translocation of NF-κBp65 was analyzed by immunofluorescence. Rat intraocular pressure (IOP) was monitored pre- and postinjection. Gene transfection efficiency and toxicity of the DMAPA-Glyp derivative were also evaluated. After RNA interference (RNAi), IκBα mRNA and protein expression were significantly inhibited. NF-κBp65 mRNA and protein expression showed no significant differences. Nevertheless, nuclear translocation of NF-κBp65 occurred in the DMAPA-Glyp+siRNA group. Both mRNA expression and activity of MMP-2 increased, with the largest increase in the DMAPA-Glyp+siRNA group. IOP in the DMAPA-Glyp+siRNA group fell to the lowest level on day 3 after RNAi. The levels of Cy3-siRNA in the ciliary muscle of the DMAPA-Glyp+siRNA group did not significantly decrease over time. At 7 and 14 d after RNAi, no significant pathological damage was detectable in the eyes injected with the DMAPA-Glyp derivative or the DMAPA-Glyp/siRNA complex. Taken together, our results suggest that downregulation of IκBα expression in the ciliary muscle plays a crucial role in reducing the IOP values of rats. IκBα may become a new molecular target for lowering IOP in glaucoma. The DMAPA-Glyp derivative is safe and feasible as an effective siRNA vector in rat eyes.

Concurrent Phacoemulsification and Encircling for Hypotony Maculopathy after Blunt Trauma

A 37-year-old Japanese man had his right eye hit by a fist. His right eye developed hypotony maculopathy and secondary cataract, and his visual acuity decreased to 20/200 with an intraocular pressure of 4 mmHg. He underwent phacoemulsification and aspiration, implantation of the intraocular lens, and encircling with a silicone tire. His visual acuity improved to 20/20 and stable for more than one year postoperatively. The intraocular pressure in his right eye increased to 12 mmHg, and maculopathy was resolved entirely. It was suggested that an encircling buckle obstructed the uveoscleral outflow through the cyclodialysis and increased intraocular pressure. Concurrent cataract surgery and encircling was sufficient to improve the vision.

Surgical resection of the sclera is a non-penetrating operation for the treatment of patients with primary open-angle and secondary glaucoma

Purpose. To evaluate the effectiveness of surgical resection of the sclera in patients with primary open-angle and secondary glaucoma. Materials and methods. The study included 84 patients with POAG and SG stages III-IV and decompensated IOP level (not higher than 32 mm Hg). In order to normalize the increased ophthalmotonus, a non - penetrating operation was performed-surgical resection of the sclera (SRS). The patients underwent complex ophthalmological examination and dynamic observation. Result. In the studied groups of patients after surgical treatment there was a decrease in elevated IOP levels by 33.42%, an improvement in the coefficient of ease of outflow and a weakening of the hypotensive regime. Stabilization of visual functions was observed in all patients. Summary. The proposed new SRS technique provides a smooth decrease in IOP, preservation of visual functions and is not accompanied by intra-and postoperative complications. Key words: primary open-angle glaucoma, surgical resection of sclera, secondary glaucoma, uveoscleral outflow pathway (USPO), intraocular pressure, EO coefficient .

Surgical resection of the sclera is a non-penetrating operation for the treatment of patients with primary open-angle and secondary glaucoma

Purpose. To evaluate the effectiveness of surgical resection of the sclera in patients with primary open-angle and secondary glaucoma. Materials and methods. The study included 84 patients with POAG and SG stages III-IV and decompensated IOP level (not higher than 32 mm Hg). In order to normalize the increased ophthalmotonus, a non - penetrating operation was performed-surgical resection of the sclera (SRS). The patients underwent complex ophthalmological examination and dynamic observation. Result. In the studied groups of patients after surgical treatment there was a decrease in elevated IOP levels by 33.42%, an improvement in the coefficient of ease of outflow and a weakening of the hypotensive regime. Stabilization of visual functions was observed in all patients. Summary. The proposed new SRS technique provides a smooth decrease in IOP, preservation of visual functions and is not accompanied by intra-and postoperative complications. Key words: primary open-angle glaucoma, surgical resection of sclera, secondary glaucoma, uveoscleral outflow pathway (USPO), intraocular pressure, EO coefficient .

Reverse meridional cyclodialysis ab interno in management of open angle glaucoma — a preliminary report

The uveoscleral outflow as an alternate route of aqueous drainage is of great interest in glaucoma surgical treatment. A cyclodialysis cleft allows one to create a direct connection between the anterior chamber (AC) and the suprachoroidal space (SCS) which is the key element of uveoscleral outflow. The purpose of the study was to evaluate the safety and effectiveness of reverse meridional cyclodialysis ab interno (RMCai) in decreasing intraocular pressure (IOP) in patients with primary open-angle glaucoma (POAG) and refractory glaucoma (RG). Fourteen patients who exhibited POAG and RG (11 men and 3 women, age 77.3 ± 7.8 years) were included in the study. All patients underwent RMCai with the help of custom-designed spatula. The spatula, inserted through a clear corneal incision, was used to detach the ciliary body from the scleral spur to create a 2.0–2.5 mm wide and 6.0–6.5 mm deep cleft. Outcome measures were IOP change, use of hypotensive medication(s), complications, and need for a second surgery. Decrease in IOP by more than 20% and IOP between 6 and 21 mmHg without hypotensive medication constituted complete success. Similar changes in IOP with medication constituted partial success. Need for second surgery constituted failure. The follow-up period was >3 months. Baseline IOP and hypotensive medication use were 22.0 ± 8.5 mmHg (95% confidence interval (CI), 17.6–26.4) and 2.6 ± 0.9 (95% CI, 2.2–3.1). At 3, 6, 12, 18, and 24 months, complete success was achieved in 64.3%, 77.8%, 55.6%, 37.5%, and 40% of patients respectively; partial success — in 14.3%, 22.2%, 44.4%, 50.0%, and 60.0%. Four patients required a second surgery. Failure occurred because of cleft closure by fibrosis. It was concluded that RMCai is safe and effective in decreasing IOP in POAG and RG patients.

Micro-invasive glaucoma surgery – an interventional glaucoma revolution

The glaucoma surgical landscape has changed dramatically over the last decade with the introduction and integration of micro-invasive glaucoma surgery (MIGS) techniques. These modalities target physiologic outflow pathways or optimize previously utilized glaucoma surgical methods in order to deliver safety, efficacy, and individualized care to the patient. MIGS techniques can be classified based on anatomical location as well as method of intraocular pressure (IOP) reduction. This review will focus on MIGS optimizing the conventional outflow pathway via intervention at Schlemm’s canal, MIGS optimizing the uveoscleral outflow pathway via suprachoroidal shunting, and MIGS optimizing the transscleral or subconjunctival outflow pathway which has long been utilized by glaucoma surgeons performing traditional filtration procedures. The wide array of currently available MIGS modalities can be staggering to the glaucoma care provider, but an understanding of the landscape and the large classes of interventional strategies can allow for clinical decision making based on the specifics of the patient’s needs and the pathophysiology of their disease.

Differences in ocular biometrics and aqueous humour dynamics between Chinese and Caucasian adults

BackgroundGlaucoma prevalence and subtype profile vary across different racial and ethnic groups. This study provides a comparative evaluation of differences in aqueous humour dynamics (AHD) and ocular biometrics in healthy Chinese and Caucasian adults of two different age groups.MethodsData from two independent studies with identical designs were compared. Cohorts included young adults (20–30 years old, 32 Chinese and 39 Caucasians) and older adults (>50 years old, 37 Chinese and 46 Caucasians). Parameters of AHD and ocular biometrics were evaluated. Group comparisons were made by generalised estimating equation methods.ResultsDifferences in young adult Caucasians compared with similarly aged Chinese were thinner central cornea (−29.27 µm, p<0.001), lower intraocular pressure (IOP) (−2.33 mm Hg, p<0.001), larger anterior chamber volume (ACV) (28.78 µL, p<0.001) and faster uveoscleral outflow rate (Fu) (0.82 µL/min, p<0.001). Differences in older adult Caucasians compared with similarly aged Chinese were slower aqueous flow rate (Fa) (−0.28 µL/min, p=0.042), lower IOP (−1.97 mm Hg, p<0.001) and larger ACV (33.15 µL, p<0.001). Considering all subjects together by race, Caucasian subjects had slower Fa (−0.22 µL/min, p=0.035), thinner corneas (−0.52 µm, p=0.003), lower IOP (−2.11 mm Hg, p<0.001), higher ACV (30.39 µL, p<0.001) and faster Fu (0.63 µL/min, p<0.001).ConclusionDifferences in AHD and biometrics between Caucasian and Chinese adults include larger ACVs which may contribute to the wider angles reported in Caucasians, and slower Fa rates coupled with faster Fu rates which may contribute to their lower IOP and lower overall risk of glaucoma.