Trans-scleral diode laser cyclophotocoagulation for refractory glaucoma after high-risk penetrating keratoplasty

Mechanism and treatment of secondary glaucoma after corneal transplantation: a review

Corneal transplantation is a common treatment for corneal diseases. Secondary glaucoma after corneal transplantation is the second leading cause of failure of keratoplasty. This article reviews the mechanism and treatment of secondary glaucoma after corneal transplantation.

Surgical management of glaucoma following different keratoplasty techniques

PURPOSE

To investigate the results of surgical management of glaucoma following different keratoplasty techniques.

METHODS

Medical records of 628 cases who underwent keratoplasty were reviewed. One hundred and eighty-eight patients (29.9%) who developed post-keratoplasty glaucoma were evaluated. Patients who could not be controlled with maximal medical treatment and underwent glaucoma surgery were included in this study. Trabeculectomy, Ahmed glaucoma valve (AGV) implantation or diode laser cyclophotocoagulation (DLC) were applied.

RESULTS

Glaucoma surgery was performed in 55 (29.3%) patients who had uncontrolled post-keratoplasty glaucoma. In penetrating keratoplasty group (n = 42), DLC was applied to 30 (71.4%) eyes, AGV to 11 (26.2%) eyes, and trabeculectomy in 1 (2.4%) eye. In Descemet's membrane endothelial keratoplasty group (n = 8), DLC was applied to 4 (50%) eyes, trabeculectomy for 3 (37.5%) eyes and AGV for 1 (12.5%) eye. In deep anterior lamellar keratoplasty group (n = 5), DLC was applied to 2 (40%) eyes, trabeculectomy to 2 (40%) eyes and AGV to 1 (20%) eye. While a statistically significant decrease was found in intraocular pressure (IOP) and anti-glaucomatous medication after surgery (p < 0.05 for each), no significant difference was found in best corrected visual acuity (BCVA). During follow-up, DLC was applied as re-glaucoma surgery in 19 (34.5%) cases. A significant reduction in IOP together with number of anti-glaucomatous medications was found with re-operation; however, a significant decrease in BCVA was noted (p < 0.05 for each).

CONCLUSION

Glaucoma surgeries after keratoplasty are effective in decreasing IOP and the number of anti-glaucomatous medication. While BCVA doesn't change after the first glaucoma surgery, after re-operation significant decrease may occur.

Lasers in Glaucoma: an Overview

Lasers have been in use as a treatment modality of glaucoma for more than last four decades. Each passing year has added newer dimensions to the existing laser technologies enhancing their safety and efficacy profile. This has become possible due to continuous research and innovations with proper understanding of the mechanism of action of different variety of lasers as treatment options. Each category of glaucoma has different underlying pathologies. Adequate knowledge and understanding of indications, limitations and hazards of these laser procedures are must before their application for improvising outcome. Recent years have witnessed a revolution this field. A thorough literature search was conducted in PubMed, Medline, the Cochrane Library Database, EMBASE, and Scopus and Google Scholar until May 2020 using the keywords, and all the articles pertaining to the relevant topics were included in this review. Purpose of this review is to summarize the important laser procedures currently in use for managing glaucoma along with updating the readers with recent advances in laser technologies, their extended applications and also analyzing possible future implications.

Surgery for glaucoma in modern corneal graft procedures

Glaucoma is a common cause of vision loss after corneal transplantion and is considered a major risk factor for graft failure. Glaucoma may be present before corneal transplant surgery, or increased intraocular pressure may develop after keratoplasty in up to one-third of patients. Pre-existing glaucoma should be controlled before keratoplasty, either medically or surgically. For postkeratoplasty increase in intraocular pressure; identifying the risk factors allows appropiate follow-up and management. Patients undergoing anterior lamellar keratoplasty may take advantage of reduced rates of postkeratoplasty glaucoma. Glaucoma also complicates eyes with endothelial keratoplasties, mostly related to management of intraocular pressure spikes derived from anterior chamber air bubbles. Nevertheless, the severity is less, and the intraocular pressure is more easily controlled when compared with penetrating keratoplasty. Adequate management of glaucoma that develops before or after keratoplasty may save eyes from irreversible damage to the optic nerve and increase graft survival.

Comparison of the diurnal efficacy and safety of cyclocryocoagulation and cyclophotocoagulation in patients with refractory glaucoma

PURPOSE

To compare the diurnal IOP-lowering efficacy and safety of cyclocryocoagulation (CCC) and cyclophotocoagulation (CPC) in patients with refractory glaucoma.

METHODS

Forty eyes of 40 Caucasian patients with advanced primary or secondary glaucoma with only tunnel vision left were included in this retrospective, comparative interventional case series. Twenty eyes treated with CCC were compared with 20 eyes treated with CPC. Primary endpoint was the reduction of 24 h mean diurnal intraocular pressure (IOP; mean of 6 measurements), peak IOP and diurnal IOP fluctuations 3 and 6 months post-treatment. Secondary outcomes were the occurrence of postoperative complications and the identification of factors influencing the postoperative IOP reduction.

RESULTS

In the CCC group (mean age 70.6 ± 13.4 years), mean diurnal IOP was significantly reduced from 20.0 ± 4.5 mmHg to 14.7 ± 2.5 (p < 0.001) at 3 months and 13.9 ± 3.34 mmHg at 6-month follow-up (p < 0.001). In the CPC group (mean age 74.9 ± 9.0 years), mean diurnal IOP significantly decreased from 18.2 ± 3.1 mmHg to 13.2 ± 2.2 (p < 0.001) at 3 months and 13.1 ± 2.6 mmHg (p < 0.001) at 6 months. At 6 months, 75% of the CCC and 63% of the CPC group had mean diurnal IOP reductions of 20% or more. The most frequent complication (25%) was a transient IOP increase during the first days after CCC. A higher preoperative mean diurnal IOP was recognized as the only factor influencing the postoperative IOP reduction after CCC and CPC.

CONCLUSIONS

Both cyclodestructive methods seem to be reasonably safe and effective in lowering 24 h mean diurnal IOP in the perspective of 6 months in patients with refractory glaucoma. The IOP-lowering effect after CCC was better but not statistically significantly different compared to CPC. A higher rate of complications was observed in the CCC group, however.

Contact Transscleral Cyclodiode Laser Treatment for Refractory Glaucoma After Penetrating Keratoplasty: Retrospective Long-term Outcomes

PRéCIS:: This is a retrospective study with long-term follow-up using transscleral cyclodiode laser photocoagulation (TCP) with low complication rate and good graft survival and intraocular pressure (IOP) control. Selective 180-degree TCP may offer a good IOP control with reduced complication rates.

PURPOSE

To study the long-term safety and efficacy of contact TCP in eyes with refractory glaucoma after penetrating keratoplasty (PKP).

PATIENTS AND METHODS

All consecutive patients who were treated with TCP for refractory glaucoma following PKP between March 1996 and February 2017 in a tertiary corneal transplantation service in the United Kingdom. Only patients with a follow-up of 5 years were included. Eligible patients were identified through the corneal transplantation service database. Medical records and database data were retrospectively analyzed and compared at 5 years from baseline.

RESULTS

In total, 28 eyes of 28 patients presented with a mean IOP of 30.4 mm Hg (SD, 7.5) at baseline despite maximally tolerated topical and systemic antiglaucoma medications. IOP was reduced significantly to 12.8 mm Hg (SD, 3.6) (P<0.0001) at 5 years with 100% of patients with a successfully controlled IOP (defined as ≤21 mm Hg). All patients had a clear graft at the beginning of the study period and at 5 years 60.7% (n=17) still presented clear grafts. The average number of topical glaucoma medication was reduced from 2.8 (SD, 0.8) to 1.7 (SD, 1.2) (P=0.019) at 5 years. Visual acuity remained stable in 67.9% of patients at 5-year endpoint. No complications (ie, hypotony or phthisis bulbi) were reported during the study period and the corneal graft failure rate remained low at 5 years (39.3%).

CONCLUSIONS

Cyclodiode laser treatment with initial selective 180-degree protocol seems to be an efficient therapeutic option in the management of patients with refractory glaucoma post-PKP when compared with other surgical alternatives. A selective 180-degree protocol seems to potentially reduce the rate of complications. Further randomized controlled studies are needed to compare outcomes with modified treatment's protocols and glaucoma drainage device.

Cyclodestructive Procedures in Glaucoma: A Review of Current and Emerging Options

The first surgical modalities to reduce aqueous humor production by damaging the ciliary body date back to the early twentieth century. Until recently, however, cyclodestructive procedures (e.g., cyclocryotherapy and transscleral diode laser photocoagulation) have been reserved as last option procedures in refractory glaucoma patients with poor visual potential. Emerging technologic innovation has led to the development of promising, safer and less destructive techniques, such as micropulse diode cyclophotocoagulation, endoscopic cyclophotocoagulation and ultrasound cyclodestruction. Consequently, an emerging paradigm shift is under way with the selection of these surgical options in eyes with less severe glaucoma and good visual potential. Although existing evidence has not, as yet, adequately defined the role and value of these procedures, their emergence is a welcome expansion of available options for patients with moderate-to-severe glaucoma. This article reviews the pertinent evidence on both established and evolving cyclodestructive techniques and describes their growing role in the management of glaucoma.

Lasers in glaucoma

While lasers have been used for many years for the treatment of glaucoma, proper indications and use of the procedures need to be considered before their application. This review summarizes the important laser procedures in Glaucoma.

Efficacy and safety of pop-titrated versus fixed-energy trans-scleral diode laser cyclophotocoagulation for refractory glaucoma

PURPOSE

To compare the efficacy and safety of pop-titrated versus fixed-energy diode laser trans-scleral cyclophotocoagulation (DLTSC) for refractory glaucoma.

METHODS

This is a prospective, interventional, longitudinal, and comparative case-control study. Patients with refractory glaucoma treated with pop-titrated DLTSC were compared to a fixed-energy DLTSC control group. Variables analyzed included: age, gender, diagnosis, pre- and post-treatment intraocular pressure (IOP). Success rate, anti-glaucoma medications reduction, and complications were analyzed at day 90 post-treatment. Primary success criterion consisted of eyes with a postoperative IOP ≤ 22 mmHg or a 30% reduction of pre-treatment IOP and managed with topical anti-glaucoma medications only.

RESULTS

A total of 68 eyes from 67 patients were included for analysis: 30 in the pop-titrated group and 38 in the fixed-energy group. Therapeutic success was achieved in 56-72% of the pop-titrated group versus 47-52% in the fixed-energy group considering the 3 different criteria analyzed (p = 0.23-0.4). There was a 22% (from 4.1 to 3.2 drugs) reduction of anti-glaucoma medications in the pop-titrated group, compared to 32% (from 3.5 to 2.4 drugs) in the fixed-energy group (p = 0.42). Five eyes (13.1%) developed hypotony, all of which belonged to the fixed-energy group (p = 0.048).

CONCLUSIONS

Pop-titrated DLTSC represents an effective and safe option for the management of refractory glaucoma. We found no statistically significant difference in success rates among both groups. However, there was a significantly higher risk of hypotony in eyes treated with the fixed-energy protocol.