Perspectives in trabecular surgery

Intra-operative optical coherence tomography in glaucoma surgery-a systematic review

The application of the OCT in clinical ophthalmology has expanded significantly since its introduction more than 20 years ago. There has been recent growing interest in the application of intra-operative optical coherence tomography (iOCT). The iOCT's ability to enhance visualisation and depth appreciation has the potential to be further exploited in glaucoma surgery, especially with the emergence of Minimally Invasive Glaucoma Surgery (MIGS)-to facilitate targeted device placement and fine surgical manoeuvres in the angles, the sub-conjunctival layer and the suprachoroidal space. Hence, this study aims to appraise the current literature on the applications of iOCT in glaucoma surgery. A total of 79 studies were identified following a literature search adhering to PRISMA guidelines. After full text evaluation, 10 studies discussing iOCT use in glaucoma surgery were included. Traditional glaucoma filtering procedures reviewed included trabeculectomy surgery, goniosynechiolysis, bleb needling and glaucoma drainage device implantation. MIGS procedures reviewed included canaloplasty, trabecular aspiration, ab-interno trabectome and the XEN45 gel stent. iOCT use in ophthalmic surgery is becoming increasingly prevalent and has already been applied in various surgeries and procedures in the field of glaucoma. With the greater adoption of MIGS, iOCT may further contribute in facilitating surgical techniques and improving outcomes. While iOCT offers many advantages, there are still limitations to be overcome-iOCT technology continues to evolve to optimise imaging quality and user-experience.

Endoscopic Goniosynechialysis for Acute Angle Closure Glaucoma Following Descemet's Stripping Automated Endothelial Keratoplasty

We describe a new modified technique to release the peripheral iridocorneal adhesions that formed after Descemet stripping automated endothelial keratoplasty. The usual technique of goniosynechialysis was modified and performed using endoscopic fiber-optic light and camera probe to aid visualization of the adherent iris tissue and carry out uneventful 270 degrees release of adhesions. The iris tissue was gently pulled away using micro forceps. The modified technique was conceptualized, as the view from the cornea was very poor due to recent lamellar surgery and corneal oedema secondary to poorly controlled intraocular pressure. The blocked trabecular meshwork system was successfully recanalized, which allowed an adequate control of intraocular pressure. The graft survived the insult and cornea gained complete clarity giving the patient the desired vision and improved quality of life.

How to cite this article: Rana M, Shah S, Pandey P, Masood I. Endoscopic Goniosynechialysis for Acute Angle Closure Glaucoma Following Descemet’s Stripping Automated Endothelial Keratoplasty. J Curr Glaucoma Pract 2018;12(2):90-93.

Medical versus surgical interventions for open angle glaucoma

BACKGROUND

Open angle glaucoma (OAG) is a common cause of blindness.

OBJECTIVES

To assess the effects of medication compared with initial surgery in adults with OAG.

SEARCH METHODS

We searched CENTRAL (which contains the Cochrane Eyes and Vision Group Trials Register) (The Cochrane Library 2012, Issue 7), Ovid MEDLINE, Ovid MEDLINE In-Process and Other Non-Indexed Citations, Ovid MEDLINE Daily, Ovid OLDMEDLINE (January 1946 to August 2012), EMBASE (January 1980 to August 2012), Latin American and Caribbean Literature on Health Sciences (LILACS) (January 1982 to August 2012), Biosciences Information Service (BIOSIS) (January 1969 to August 2012), Cumulative Index to Nursing and Allied Health Literature (CINAHL) (January 1937 to August 2012), OpenGrey (System for Information on Grey Literature in Europe) (www.opengrey.eu/), Zetoc, the metaRegister of Controlled Trials (mRCT) (www.controlled-trials.com) and the WHO International Clinical Trials Registry Platform (ICTRP) (www.who.int/ictrp/search/en). We did not use any date or language restrictions in the electronic searches for trials. We last searched the electronic databases on 1 August 2012. The National Research Register (NRR) was last searched in 2007 after which the database was archived. We also checked the reference lists of articles and contacted researchers in the field.

SELECTION CRITERIA

We included randomised controlled trials (RCTs) comparing medications with surgery in adults with OAG.

DATA COLLECTION AND ANALYSIS

Two authors independently assessed trial quality and extracted data. We contacted study authors for missing information.

MAIN RESULTS

Four trials involving 888 participants with previously untreated OAG were included. Surgery was Scheie's procedure in one trial and trabeculectomy in three trials. In three trials, primary medication was usually pilocarpine, in one trial it was a beta-blocker.The most recent trial included participants with on average mild OAG. At five years, the risk of progressive visual field loss, based on a three unit change of a composite visual field score, was not significantly different according to initial medication or initial trabeculectomy (odds ratio (OR) 0.74, 95% confidence interval (CI) 0.54 to 1.01). In an analysis based on mean difference (MD) as a single index of visual field loss, the between treatment group difference in MD was -0.20 decibel (dB) (95% CI -1.31 to 0.91). For a subgroup with more severe glaucoma (MD -10 dB), findings from an exploratory analysis suggest that initial trabeculectomy was associated with marginally less visual field loss at five years than initial medication, (mean difference 0.74 dB (95% CI -0.00 to 1.48). Initial trabeculectomy was associated with lower average intraocular pressure (IOP) (mean difference 2.20 mmHg (95% CI 1.63 to 2.77) but more eye symptoms than medication (P = 0.0053). Beyond five years, visual acuity did not differ according to initial treatment (OR 1.48, 95% CI 0.58 to 3.81).From three trials in more severe OAG, there is some evidence that medication was associated with more progressive visual field loss and 3 to 8 mmHg less IOP lowering than surgery. In the longer-term (two trials) the risk of failure of the randomised treatment was greater with medication than trabeculectomy (OR 3.90, 95% CI 1.60 to 9.53; hazard ratio (HR) 7.27, 95% CI 2.23 to 25.71). Medications and surgery have evolved since these trials were undertaken.In three trials the risk of developing cataract was higher with trabeculectomy (OR 2.69, 95% CI 1.64 to 4.42). Evidence from one trial suggests that, beyond five years, the risk of needing cataract surgery did not differ according to initial treatment policy (OR 0.63, 95% CI 0.15 to 2.62).Methodological weaknesses were identified in all the trials.

AUTHORS' CONCLUSIONS

Primary surgery lowers IOP more than primary medication but is associated with more eye discomfort. One trial suggests that visual field restriction at five years is not significantly different whether initial treatment is medication or trabeculectomy. There is some evidence from two small trials in more severe OAG, that initial medication (pilocarpine, now rarely used as first line medication) is associated with more glaucoma progression than surgery. Beyond five years, there is no evidence of a difference in the need for cataract surgery according to initial treatment.The clinical and cost-effectiveness of contemporary medication (prostaglandin analogues, alpha2-agonists and topical carbonic anhydrase inhibitors) compared with primary surgery is not known.Further RCTs of current medical treatments compared with surgery are required, particularly for people with severe glaucoma and in black ethnic groups. Outcomes should include those reported by patients. Economic evaluations are required to inform treatment policy.

Excimer laser trabeculotomy: a new, minimally invasive procedure for patients with glaucoma

BACKGROUND

Excimer laser trabeculotomy (ELT) ab interno is a new surgical technique to reduce intraocular pressure (IOP) in patients with glaucoma or ocular hypertension. Our purpose was to examine IOP reduction and the use of antiglaucoma drugs (AGD) in patients treated with ELT and to evaluate the safety of this laser treatment.

METHODS

To increase the outflow of aqueous humor, ten microperforations of the trabecular meshwork were performed by an endoscope-guided photoablative laser probe (Excimer laser, AIDA, TUI-Laser, Munich; pulse energy: 1.2 mJ at fiber tip, pulse duration: 60 ns, repetition rate: 20 Hz). Average operation time usually was about 2 min. In our pilot study, one group of patients without cataract underwent ELT, the other group with cataract underwent phacoemulsification (PHACO) plus ELT. IOP, visual acuity, and AGD were determined preoperatively (T0) and 2-4 months (T1), 5-7 months (T2), 11-13 months (T3), and 22-26 (T4) months after surgery. Treatment was defined to be successful if (1) postoperative IOP was < or =21 mmHg, and (2) IOP reduction was at least 20%.

RESULTS

ELT reduced the IOP from 24.1+/-0.7 (n=69) mmHg preoperatively to 18.8+/-0.4 (T1, n=66), 20.0+/-0.5 (T2, n=51), 18.8+/-0.8 (T3, n= 37), and 16.8+/-1.0 (T4, n=15) mmHg, respectively. However, 28% of the eyes needed repeat surgery due to insufficient IOP reduction. According to Kaplan-Meier statistics, the success rate was 60% (T1), 49% (T2), and 46% (T3), respectively. The number of AGD was 1.9+/-0.1 (T0), 1.2+/-0.2 (T1), 1.3+/-0.2 (T2), 1.8+/-0.2 (T3), and 1.5+/-0.3 (T4). Combined phacoemulsification plus ELT reduced the IOP from 22.4 mmHg+/-0.6 (T0, n=57) to 16.5+/-0.4 (T1, n=52), 16.1+/-0.5 (T2, n= 40), 16.4+/-0.4 (T3, n= 35), and 12.8+/-1.5 (T4, n=4) mmHg, respectively; 7% of the eyes treated with the combined procedure needed repeat surgery due to insufficient IOP reduction. According to Kaplan-Meier statistics, the success rate was 85% (T1), 74% (T2), and 66% (T3), respectively. The number of AGD was 1.1+/-0.2 (T0), 0.9+/-0.2 (T1), 1.1+/-0.2 (T2), 1.2+/-0.2 (T3), and 1.8+/-0.9 (T4).

CONCLUSIONS

ELT, especially in combination with phacoemulsification, is a new, promising, minimally invasive laser treatment to reduce IOP for at least 1-2 years. ELT alone is less effective in IOP reduction.

Medical versus surgical interventions for open angle glaucoma

BACKGROUND

Open angle glaucoma (OAG) is the commonest cause of irreversible blindness worldwide.

OBJECTIVES

To study the relative effects of medical and surgical treatment of OAG.

SEARCH STRATEGY

We searched the Cochrane Central Register of Controlled Trials (The Cochrane Library Issue 1, 2005), MEDLINE (1966 to February 2005), EMBASE (1988 to February 2005), and reference lists of articles. We also contacted researchers in the field.

SELECTION CRITERIA

Randomised controlled trials comparing medications to surgery in adults.

DATA COLLECTION AND ANALYSIS

Two authors independently assessed trial quality and extracted data. We contacted trial investigators for missing information.

MAIN RESULTS

Four trials involving 888 participants with previously untreated OAG were included. Surgery was Scheie's procedure in one trial and trabeculectomy in three trials. In three trials, primary medication was usually pilocarpine, in one trial a beta-blocker. In the most recent trial, participants with mild OAG, progressive visual field (VF) loss, after adjustment for cataract surgery, was not significantly different for medications compared to trabeculectomy (Odds ratio (OR) 0.74; 95% CI 0.54 to 1.01). Reduction of vision, with a higher risk of developing cataract (OR 2.69, 95%% CI 1.64 to 4.42), and more patient discomfort was more likely with trabeculectomy than medication. There is some evidence, from three trials, for people with moderately advanced glaucoma that medication is associated with more progressive VF loss and 6 to 8 mmHg less intraocular pressure (IOP) lowering than surgery, either by a Scheie's procedure or trabeculectomy. There was a trend towards an increased risk of failed IOP control over time for initial pilocarpine treatment compared to trabeculectomy. In the longer-term (two trials) the risk of failure was significantly greater with medication than trabeculectomy (OR 3.90, 95% CI 1.60 to 9.53; HR 7.27, 95% CI 2.23 to 25.71). Medicine and surgery have evolved since these trials were undertaken, and additionally the evidence is potentially subject to detection and attrition bias.

AUTHORS' CONCLUSIONS

Evidence from one trial suggests, for mild OAG, that VF deterioration up to five-years is not significantly different whether treatment is initiated with medication or trabeculectomy. Reduced vision, cataract and eye discomfort are more likely with trabeculectomy. There is some evidence, for more severe OAG, that initial medication (pilocarpine, now rarely used as first line medication) is associated with greater VF deterioration than surgery. In general, surgery lowers IOP more than medication. There was no evidence to determine the effectiveness of contemporary medication (prostaglandin analogues, alpha2-agonists and topical carbonic anhydrase inhibitors) compared to surgery in severe OAG, and in people of black African ethnic origin who have a greater risk of more severe open angle glaucoma. More research is required.

Lasers in ophthalmology

Laser technology continues to progress with the addition of new lasers, new delivery systems, and new applications. The introduction of lasers to veterinary ophthalmology has radically changed the level of care that we can provide to our patients. The development of the diode laser has particularly had an impact on veterinary ophthalmology. The diode's affordability, portability, and broad applications for veterinary patients have allowed laser surgery to become a routine part of veterinary ophthalmology practice. Educating the public and veterinary community in available laser techniques will generate improved ophthalmic care and provide more data on which to build future applications.