11th Consensus Meeting: Glaucoma Surgery
Melbourne, Australia, March 26, 2019
Edited by: Robert N. Weinreb, Pradeep Ramulu, Fotis Topouzis, KiHo Park, Kaweh Mansouri and Fabian Lerner
2019. Many photos and figures. Hardbound.
ISBN-10: 90 6299 280 3
ISBN-13: 978 90 6299 280 5
Published by: Kugler Publications.
Click here for more information on all publications in the Consensus series.
Summary Consensus Points
- Guidelines for clinical surgical trials and outcome measures
- Approach to primary open-angle glaucoma
- Approach to angle-closure glaucoma
- Approach to other glaucomas
Section 1 – Guidelines for clinical surgical trials and outcome measures
- The benefits and risks of any new glaucoma surgical procedure should be considered in relation to established and accepted interventions to lower intraocular pressure (IOP).
- The randomized controlled clinical trial is the most valid approach to evaluate the safety, efficacy, and effectiveness of a new glaucoma procedure.
- Good study design reduces the potential for bias, and combined with good reporting increases confidence in the conclusions of trials. Hypotheses and both primary and secondary outcomes (including safety measures and statistical methods) should be determined before initiation of a study to optimize reporting of outcomes.
- If low IOP is associated with structural changes in the eye and/or worse vision, it should be considered as a complication.
- Medication washouts may not be possible in eyes with moderate to advanced disease.
- Non-compliance with preoperative medications or addition of ineffective medications prior to surgery may make medication reduction from surgery appear artificially high.
- The target IOP needs to be defined and articulated prior to initiating the study for each individual.
- IOP goals may be stated as a percentage reduction or a “target pressure.”
- Reporting success for specific IOP thresholds can lead to misclassification of success or failure if the treating physician is not seeking to achieve that IOP threshold with surgery and during the postoperative period.
- Decisions regarding if and when IOP-lowering medications are reintroduced after surgery should be determined by protocol, and not left purely to the discretion of the treating physician.
- Tables and figures that integrate IOP and medication usage can be used to better describe IOP outcomes (see Fig. 1).
- Changes in IOP can be readily measured and are particularly useful for judging success in studies of shorter duration.
- Following patients for visual field changes after surgery is desirable.
- In addition, scatterplots of preoperative vs postoperative IOP allow comparison among studies.
- Consideration should be given to make individual patient data available for meta-analyses and systematic reviews.
- Average changes in acuity are not always useful in capturing the risks of an operation.
- Monitoring large numbers of operations for uncommon, catastrophic events is more likely to pick up these complications than clinical trials.
- All clinical research studies of treatment outcomes in glaucoma should collect patient-centered outcome data. More work is required to identify the ideal measures (e.g. patient-reported outcome measures; PROMS) to be used for this purpose.
Further work needs to be done to determine if structural measures of the optic disc, macula, and retinal nerve fiber layer are suitable for determining surgical outcomes.
More work is required to develop a consensus regarding which complications occurring after glaucoma surgery are minor or severe.
- Classification of severity should take into account the typical visual declines occurring in the context of the complication, the risk of the complication to the patient’s sight, and the effect of the complication on the patient (i.e. their preoperative human function, inconvenience, anxiety, and discomfort).
Section 2 – Techniques
- The prognosis of filtering surgery is related to the preoperative condition of the conjunctiva, cornea, and lid margin.
- The discontinuation of antiglaucomatous drugs to reduce hyperemia and inflammation could improve the preoperative condition of the conjunctiva. One may consider substituting with oral medications to reduce intraocular pressure (IOP) temporarily.
- The treatment of significant lid margin disease, blepharitis, and ocular surface disease can help improve surgical outcomes.
- The use of topical steroids in the preoperative period may enhance the condition of the conjunctiva.
- There is inconclusive evidence whether anti-VEGF (vascular endothelial growth factor) drugs also reduce conjunctival scarring.
- There is inconclusive evidence whether the delivery method (intraoperative sponge vs subconjunctival injection) of antimetabolites affects outcomes.
- Of the many factors that can affect success rate, the data are inconclusive in regard to dose, exposure times, and treated surface area.
- Phacoemulsification after trabeculectomy increases the likelihood of bleb failure.
- In open-angle glaucoma, trabeculectomy in pseudophakic eyes has a higher risk of failure than in phakic eyes. Results after clear corneal cataract surgery may be better than after a conjunctival incision.
- It is unclear if results are enhanced with a longer time frame between procedures.
- Antimetabolites (5-FU or MMC) can be applied peri- and postoperatively by subconjunctival injection.
- Both 5-FU and MMC may induce complications.
B. Nonpenetrating surgery
- Although deep sclerectomy, viscocanalostomy, and canaloplasty appear to be safer than trabeculectomy, these methods are generally less effective than trabeculectomy.
- The use of antimetabolites and space-maintainers enhances surgical results.
- Postoperative YAG-laser goniopuncture is often needed for IOP control.
C. Glaucoma drainage devices (GDD)
- The Baerveldt implant may be associated with better long-term IOP control than the Ahmed implant, but the latter is associated with fewer serious complications.
- Glaucoma drainage tubes may be inserted through a partial-thickness scleral flap or tunnel, or covered with a donor graft patch, in order to prevent tube exposure or tube migration.
- There is no evidence to suggest that a better long-term survival of GDD surgery is dependent on the type of graft material or the use of antimetabolites.
- Nonvalved implants require the creation of mechanisms that will restrict flow to prevent postoperative hypotony. Intraluminal stents and occlusion sutures around the tube are frequently used to avoid this complication.
- The Molteno implant is an alternative GDD.
D. Minimally invasive glaucoma surgery (MIGS)
- Trabecular outflow
Trabecular meshwork/Schlemm’s canal microbypass stents (iStent, iStent Inject, Hydrus) are best used for open-angle glaucoma patients with IOP targets in the mid-teens and higher.
- Randomized controlled trials (RCTs) show a slightly higher IOP-lowering effect and/or medication reduction of combined phacoemulsification with trabecular meshwork/Schlemm’s canal microbypass stents than phacoemulsification alone for up to two years.
- Stand-alone stent procedures have shown IOP lowering and medication reduction.
- An RCT demonstrated a higher IOP-lowering effect of stand-alone Hydrus compared to iStent.
- Devices that can be used for AIT include the Trabectome, the Kahook Dual Blade, gonioscopy-asissted transluminal trabeculotomy (GATT), and the Goniotome.
- RCTs are needed to compare outcomes of AIT to other MIGS procedures, trabeculectomy, GDDs, and other surgical procedures.
Because of increased rates of endothelial cell loss, the CyPass was voluntarily withdrawn from the market and further implantation is not advised at present.
- Patients who have had a CyPass implanted should be monitored for signs of corneal decompensation.
- If there are clinical signs of corneal decompensation developing, the implant should be considered for trimming flush with the iris root/scleral spur or explantation, with a discussion of the risks and benefits of intervention.
The XEN gel stent is a procedure that can achieve IOPs in the low to mid teens.
- Although off-label, creating an ab interno bleb with a gel stent may benefit from the use of a subconjunctival antimetabolite.
- In cases of excessive subconjunctival fibrosis, needling or open revision may be needed to improve the overall success of the procedure.
- The intraoperative complications of the procedure are low across trials, although severe postoperative complications, such as hypotony maculopathy and endophthalmitis, can occur.
- To date, it is unclear whether failed primary XEN gel stent surgery affects subsequent trabeculectomy outcomes negatively.
- Results of an ongoing RCT comparing the XEN gel stent to trabeculectomy are not yet available.
Ab externo subconjunctival outflow procedures (Preserflo microshunt) have the potential to achieve IOPs in the low to mid teens.
- Results of an ongoing RCT comparing the Preserflo microshunt to trabeculectomy are not yet available.
- Results of ab externo XEN gel stents are not yet available.
To date, accumulating short-term studies support some MIGS procedures as an alternative in patients with mild to moderate glaucoma.
- High quality randomized clinical trial data with long follow-up durations are needed.
RCT data comparing MIGS procedures to each other and to other treatment modalities, in all stages of disease, are needed.
- Cost-effective analysis is needed.
Data from non-Caucasian populations are also needed.
E. Laser trabeculoplasty
- Laser trabeculoplasty may be a viable option for achieving additional lowering of IOP and/or delaying the time of surgery in patients on medical therapy or not using medical therapy.
- Laser trabeculoplasty may be considered as first-line therapy.
- In selective laser trabeculoplasty (SLT), the initial power of 0.5-0.7 mJ is titrated upwards till fine bubbles are just seen.
- In primary open-angle glaucoma (POAG) eyes, 360° of angle should be treated in one or two sessions.
- A check of IOP at least one hour following treatment is recommended to detect and treat, if indicated, postoperative IOP spikes.
- Peak IOP lowering typically occurs at least one to two months following the procedure.
F. Cyclodestructive procedures
- While effective at lowering IOP, these procedures typically have limited use in early disease.
- While cycloablative interventions were traditionally used for refractory glaucoma or as a surgery of last resort, these procedures often can be considered for use earlier in the surgical management of glaucoma.
- Endocyclophotocoagulation in combination with lens extraction may help open the angle in patients with plateau iris syndrome, by shrinking the ciliary body and its processes away from the posterior iris and angle structures.
- RCTs are needed to compare cyclodestructive procedures to other surgical techniques.
G. Goniosynechialysis (GSL)
- Early (e.g. within six months of acute attack of angle closure) GSL in combination with cataract surgery may be effective in eyes with synechial angle closure.
Section 3 – Approach to primary open-angle glaucoma
A. When to consider a surgical approach
- Overview of nonsurgical options
Medical treatment is the most common initial intervention to lower intraocular pressure (IOP) and is effective for the majority of patients with primary open-angle glaucoma (POAG).
- Overview of nonsurgical options
Monotherapy is the initial treatment in most patients. Laser trabeculoplasty can be considered as the initial treatment in POAG patients.
- Prostaglandins are currently the most effective topical medications for decreasing IOP.
- With intolerance, poor efficacy, or patient preference, another agent should be substituted.
- If monotherapy is effective but the IOP target is not reached, a second or a third drop from a different class of medications can be added.
- Preservative-free eye drops should be considered in POAG patients with pre-existing ocular surface disease or intolerance to preservatives.
In the absence of useful vision, the goal of treatment in POAG is to maintain patient comfort with the minimum necessary treatment.
Laser trabeculoplasty can be considered as an initial treatment for ocular hypertensive and mild to moderate glaucoma (as opposed to medications).
- The LiGHT trial showed that in patients with ocular hypertension or mild to moderate glaucoma:
- Selective laser trabeculoplasty (SLT) can achieve target IOP control without medications in nearly 75% of eyes after three years of follow-up.
- SLT can achieve target IOP better than topical medications, and reduce the need for further glaucoma surgery.
Cataract surgery is not recommended as a sole treatment to decrease IOP in POAG when there is evidence or high risk of disease progression.
- Cataract surgery in POAG has been shown to provide, for some patients, IOP reduction of 2-4 mmHg for as long as two years.
The decision to operate relies on the evidence of disease progression or high risk of progression.
- There is no consensus upon the level of visual field or structural (optic disc, retinal nerve fiber layer, etc.) loss that would necessitate a surgical approach in POAG.
- Baseline testing should be readjusted following a treatment intervention.
- Attention should also be paid to test-location-specific changes, particularly in visual field defects that threaten fixation.
- Surgery should be considered in a patient who already is in an advanced state of glaucoma by the time of presentation.
Consideration for surgery also should be given to patients who are poorly adherent to medical treatment, intolerant of their medications, or unable to access their medications.
Standard automated perimetry and progression analysis tools for both structure and function may be less reliable in cases of advanced visual field loss.
Surgical options in POAG should take into account several factors, including: age; baseline IOP; stage of the disease; rate of progression; lens status and need for cataract surgery; compliance with treatment; success rate of each intervention and expected time to possible failure; as well as availability for postoperative follow-up.
Once relevant topics regarding surgical intervention have been properly addressed, it is mandatory to obtain consent before any procedure is performed.
- All necessary information needs to be provided in a comprehensive and well-understood language to the patient, who needs to understand well the potential risk and intended benefit of the surgery.
B. Procedure selection for primary surgery in POAG
- Severity of disease/IOP goal
A comprehensive, preoperative assessment should be performed in order to select the most appropriate surgical procedure for each individual patient.
- Severity of disease/IOP goal
In general, incisional surgery or tube shunts are the preferred treatment options for advanced POAG.
- The predictability, safety, and/or long-term IOP lowering of all surgical techniques need to be considered when selecting the procedure.
Fast rates of progression and highly elevated preoperative IOP levels may require procedures that are more effective in achieving lower IOP goals, even in early stages of the disease.
Medication intolerance, unaffordability, nonadherence, and poor access to medical treatment may necessitate surgical intervention.
The affordability of procedures to the patient should be considered when selecting amongst surgical options.
Attentive, early, postoperative care is important for enhancing surgical outcomes, particularly for those procedures involving subconjunctival blebs.
The selection of the first glaucoma surgical procedure may impact the results of further interventions, if needed.
Trabeculectomy remains the reference standard for moderate to severe glaucoma to which other procedures should be compared.
Careful preoperative decisions and attentive postoperative care decrease the likelihood of complications.
There is limited information about the impact of ethnicity/race on the outcomes of different surgical procedures.
- Individuals of African descent have more conjunctival scarring when compared to individuals of European descent.
Trabeculectomy may be less effective in younger POAG patients (i.e. those with juvenile open-angle glaucoma [JOAG]).
- Studies evaluating the safety and efficacy of minimally invasive glaucoma surgery (MIGS) procedures in JOAG are sparse.
Lens status has an important part in the decision making process, not just in whether to perform combined surgery, but by impacting the success of the operation.
Tube shunts can be effective in situations where the success rate and safety of trabeculectomy is more limited (e.g. prior intraocular surgery or prior failed trabeculectomy).
Tube shunts are often performed if the eye has extensive conjunctival involvement with a scleral buckle.
- If the buckle is placed quite posteriorly, trabeculectomy also may be a reasonable approach.
- Small-gauge vitrectomy may not preclude a trabeculectomy.
Highly myopic individuals are more likely to have hypotony maculopathy after trabeculectomy/shunt and have a higher risk of additional vision loss compared to emmetropes.
In consultation with the internist or general medical doctor, the risks and benefits of discontinuing antiplatelet or anticoagulant agents needs to be considered for each patient.
- If safe, many surgeons discontinue antiplatelet or anticoagulant therapy.
C. Procedure selection in eyes with prior surgery
- Prior cataract surgery
Glaucoma drainage devices (GDDs), trabeculectomy, and many other less invasive surgeries may be considered as alternative options for surgery in eyes with unscarred conjunctiva after clear corneal phacoemulsification.
- Prior cataract surgery
Well-healed, conjunctival-sparing cataract surgery has limited implications on the success of glaucoma surgery.
- Prior glaucoma surgery
The choice of second glaucoma surgery should be individualized to the patient and is influenced by several factors, including prior surgical procedure, degree of conjunctival scarring, target IOP, corneal endothelial status, and visual potential.
- Prior glaucoma surgery
GDDs are an option in eyes with previous incisional glaucoma surgery.
- Conjunctival scarring from past surgery or other causes
Trabeculectomy is a surgical option in eyes which have previously undergone ophthalmic surgeries not associated with conjunctival scarring and which require a low target IOP.
- Conjunctival scarring from past surgery or other causes
Ophthalmic surgeries associated with conjunctival scarring increase the risk of failure for filtration surgery. GDDs remain an option in most eyes with conjunctival surgery, even when superior conjunctiva is scarred.
- History of prior or ongoing complications in same/contralateral eye
If glaucoma surgery is associated with a sight-threatening complication in one eye, it increases the risk of the same complication occurring in the fellow eye and impacts the prognosis.
- Patients need to be counselled about these situations and alternative surgical procedures may be warranted in such situations.
D. General (non-surgery-specific) postoperative recommendations
- It remains unclear what steroid regimen (potency, frequency, and duration) is required to optimize glaucoma surgery outcomes.
- Steroid response can also occur after glaucoma surgery.
- Cataract progression is a frequent late complication of filtering surgery, and perhaps other glaucoma surgeries as well. Accordingly, it is important to discuss the risk of cataract development with the patient.
Section 4 – Approach to angle-closure glaucoma
- Indications for surgery in angle closure
As different underlying mechanism(s) may affect the outcome of treatment in angle closure, intraocular pressure (IOP) lowering cannot be predicted on the basis of baseline factors.
- Indications for surgery in angle closure
An anteriorly positioned ciliary body, a thick iris, and a greater degree of closure at baseline are associated with risk of residual angle closure after laser peripheral iridotomy (LPI).
- Indications for surgery in angle closure
Based on data from recent trials, the benefit of prophylactic laser iridotomy over five to six years appears to be small in Chinese patients who are primary angle-closure suspects (PACS).
- Whether the same results are repeatable in non-Chinese populations remains to be determined.
he goal for IOP lowering in angle-closure glaucoma is likely similar to that seen in open-angle glaucoma, and therefore initial treatment should aim to lower IOP, depending on patient factors and disease severity.
Generally, LPI is effective for relieving pupillary block in eyes with primary angle-closure disease.
- This includes PACS, primary angle closure (PAC), and primary angle-closure glaucoma (PACG).
- Up to one-third of patients show residual iridotrabecular contact despite a patent LPI and relief of pupil block.
Effectiveness of LPI may decrease with increased severity of the disease — in terms of greater degree of peripheral anterior synechiae (PAS), a higher IOP, and a greater cup-to-disc ratio.
- Studies showed that most PACS eyes did not need any further intervention after LPI, while many PAC, PACG, and acute PAC eyes required additional treatment to control IOP.
- In eyes with > 180° PAS there is potential for IOP spikes following LPI.
Argon laser peripheral iridoplasty (ALPI) can be applied in the conditions involving non-pupillary-block appositional angle closure, such as plateau iris and nanophthalmos.
- A Cochrane review did not find sufficient evidence to recommend its use in all cases of PAC and PACG.
ALPI can be an effective procedure to break iridotrabecular contact in an acutely symptomatic angle closure.
- Iridoplasty can be used as a first-line treatment or in cases that are refractory to medical treatments.
- However, iridoplasty does not replace iridotomy for the treatment of angle closure.
Selective laser trabeculoplasty has been shown to produce a mild reduction in IOP in the short term for PAC and PACG where the angle opens up at least 180° after iridotomy. However, its utility in eyes with more than 180° of synechial angle closure is unknown and likely limited.
- Argon laser trabeculoplasty has overall poor long-term success rates and is currently not recommended for any form of PAC or PACG.
There are few studies evaluating specifically transscleral cyclophotocoagulation (TSCPC) and micropulse TSCPC in angle-closure patients.
- Lens extraction
In patients with co-existing cataract and angle-closure disease, lens extraction surgery is an effective intervention and often associated with a substantial reduction in IOP.
- Lens extraction
Clear lens extraction (CLE) can be considered for the initial management of mild to moderate PACG, as well as PAC with IOP > 30 mmHg, for patients over 50 years of age.
- The increase in average angle-width parameters was significantly greater after cataract extraction compared with LPI.
- In the EAGLE trial, CLE resulted in slightly better IOP lowering, reduced medication use and subsequent glaucoma surgery, improved quality of life, and cost effectiveness compared to LPI.
- In non-Chinese/non-European populations these results are uncertain.
- Lens extraction can be more complicated intraoperatively and postoperatively than for routine eyes.
Combined lens surgery and trabeculectomy (phaco-trabeculectomy) should be considered when there are clinical indications for both lens extraction and trabeculectomy in the same eye.
- These indications include visually significant cataract and/or the lens is deemed a major contributory cause of angle closure, as well as target IOP not achieved with maximally tolerated glaucoma medications and less invasive interventions and/or the IOP reduction from phacoemulsification alone is deemed not sufficient to achieve the perceived target IOP.
- Phaco-trabeculectomy lowers IOP more effectively than phacoemulsification alone in treating uncontrolled PACG; however, it may be associated with more surgical complications.
- Phaco-trabeculectomy may not be warranted in medically controlled PACG due to the increased rate of complications compared to phacoemulsification alone.
- Phaco-trabeculectomy is associated with fewer subsequent surgeries compared to trabeculectomy in PACG, with similar IOP-lowering effect.
- There is no significant difference in outcome when performing phaco-trabeculectomy through one or two sites.
Trabeculectomy alone is not recommended immediately after an acute angle closure (AAC) episode.
Modifications to the surgical technique of trabeculectomy in PACG have been suggested to avoid complications and improve the outcome.
- This includes possibly using one or more of the following: lowering IOP before trabeculectomy by intravenous mannitol; making a more anteriorly placed sclerostomy; avoiding extreme IOP fluctuations during the intraoperative period by maintaining a deep anterior chamber; applying multiple, tight scleral flap sutures, preplacement of sutures before the sclerostomy; conservative suture lysis or removal, as well as the use of cycloplegic therapy.
- No prospective studies assessing the beneficial effects of the above modifications have been described in the literature.
- Phacoemulsification alone is often effective and might reduce postoperative complications.
In medically uncontrolled chronic PACG in phakic eyes, both phacoemulsification and trabeculectomy are effective in reducing IOP.
- If there is uncontrolled PACG and advanced damage, phacoemulsification alone may not be sufficient.
Trabeculectomy is more effective than phacoemulsification in reducing dependence on glaucoma drugs but is associated with more complications, deterioration in visual function, and multiple subsequent surgical interventions.
Factors associated with failure of trabeculectomy in PACG eyes include absence of LPI, presence of a crystalline lens, and diabetes mellitus. Increased age, limbus-based conjunctival flaps, and mitomycin C (MMC) duration > 1 minute were associated with increased chances of surgical success.
Glaucoma drainage device surgery
- Glaucoma drainage device surgery alone
Glaucoma drainage device (GDD) surgery can be considered in individuals with sufficiently deep anterior chambers who are pseudophakic or phakic. In pseudophakic eyes with a shallow chamber, tube placement can be performed in the ciliary sulcus.
- There is a lack of evidence comparing the results of GDD with trabeculectomy.
- Combined lens and GDD surgery
Combined cataract and GDD surgery should be considered when there are clinical indications for both lens extraction and glaucoma drainage implant surgery in the same eye.
- Combined surgery has an additive effect on IOP lowering compared to each surgery alone; however, it may be associated with greater risk of surgical complications.
- Goniosynechialysis alone
There is minimal evidence for the use of goniosynechialysis (GSL) alone to lower IOP in PACG.
- Combined lens and GSL surgery
Combined lens and GSL surgery can be considered when there are clinical indications to lower the IOP in the presence of more than 180° PAS angle closure and a visually significant cataract.
- There are conflicting data on the efficacy of phacoemulsification + GSL, but two RCTs showed no benefit of phacoemulsification + GSL over phacoemulsification alone.
- PACG eyes undergoing GSL combined with phacoemulsification have significantly increased aqueous outflow facility compared to phacoemulsification alone.
While minimally invasive glaucoma surgery have been used off license in angle closure, the literature is sparse and to date there are no published RCTs.
- Angle procedures are at risk of occlusion in angle closure due to smaller anterior chambers and proximity of the iris.
Cyclodestructive procedures (e.g. transscleral cyclophotocoagulation, endoscopic cyclophotocoagulation, and high-frequency ultrasound) may have similar risk profiles in open-angle glaucoma and angle closure but few data exist.
- Cyclodestruction has been proposed as a means to alter ciliary body shape in plateau iris (cilioplasty), but without outcome data available yet.
There remains a place for surgical iridectomy in specific clinical situations of PAC or PACG.
- A surgical iridectomy may be required if a laser iridotomy has failed to break an attack of angle closure, in resource-poor areas without access to a laser, or if laser iridotomy cannot be practically achieved.
Anterior chamber paracentesis is an option to provide a rapid IOP reduction and pain relief in selected patients with AAC.
- Complications may occur, including: cornea, iris, or lens damage; lens dislocation; shallowing of the anterior chamber; bleeding; misdirection glaucoma; and decompression retinopathy.
Although there has been increasing knowledge on the pathogenic mechanisms underlying angle-closure disease, there is ambiguity regarding the different surgical interventions and their timing.
Section 5 – Approach to other glaucomas
A. Exfoliation glaucoma
- The therapeutic algorithm for exfoliation glaucoma (XFG) is similar to primary open-angle glaucoma (POAG).
- There are more intraocular pressure (IOP) fluctuations and faster progression with XFG, requiring a close follow-up.
- Need for selective laser trabeculoplasty (SLT) or earlier surgery is more frequent in XFG compared to POAG.
- Energy settings may need to be reduced in areas of increased trabecular meshwork pigmentation.
- Special caution is required with respect to early post-laser IOP spikes and decreased efficacy over time.
- Minimally invasive glaucoma surgery (MIGS) procedures that target the trabecular meshwork seem to work well in mild to moderate XFG, results being comparable to POAG. In the USA, the XEN gel stent has approval from the Food and Drug Administration (FDA) to be used in XFG. However, close follow-up is recommended as long-term results are not known.
B. Pigmentary glaucoma
- No direct comparisons of different surgical options for pigmentary glaucoma (PG) have been performed to date, and there is currently no clearly superior surgical approach.
- SLT, trabeculectomy, and nonpenetrating glaucoma surgery may be considered in patients with PG not controlled by maximal medical therapy.
- Some MIGS techniques could also be considered in subjects with PG. In the US, the XEN gel stent has FDA approval to be used in PG.
- Laser peripheral iridotomy (LPI) may be effective in reducing the pigment load, particularly for eyes with concave iris configuration and free-floating iris pigment.
C. Steroid-induced glaucoma
- After discontinuing steroids, management of steroid-induced glaucoma or steroid-induced ocular hypertension is similar to POAG.
- If patient condition allows it, corticosteroids should be discontinued for at least a few weeks to elicit a lower IOP before considering surgery.
- In a patient with steroid-induced glaucoma and raised IOP, discontinuation of steroids may reduce IOP. This may result in overestimation of the surgical outcome.
- SLT is sometimes effective for steroid-induced glaucoma.
- Trabeculectomy is effective for steroid-induced glaucoma.
D. Traumatic glaucoma
- Pilocarpine and/or SLT are not recommended for the management of glaucoma associated with angle recession.
- Trabeculectomy with mitomycin C (MMC) in post-traumatic glaucoma is an effective method to reduce IOP.
- Glaucoma drainage devices (GDDs) are other options for the management of traumatic glaucoma.
- Transscleral or endoscopic cyclophotocoagulation can be considered in traumatic glaucoma refractory to these other surgeries.
E. Uveitic glaucoma
- Management of uveitic glaucoma depends on the type of uveitis, severity of inflammation, pathology of the angle, possibility of steroid-induced glaucoma, and necessity of long-term corticosteroid use.
- Trabeculectomy with antimetabolites and GDDs are surgical options for uveitic glaucoma.
- Preoperative preparation should ameliorate any anterior chamber inflammation.
- Hypotony maculopathy is a major complication.
- An iridotomy can close but can be reopened. Surgical iridectomy could be considered in this situation, particularly if an LPI closes.
F. Neovascular glaucoma
- Reduction of the ischemic stimulus in neovascular glaucoma, typically by panretinal photocoagulation, is critical for long-term control of the disease. Anti-VEGF (vascular endothelial growth factor) intravitreal injections provide a useful adjunct for the treatment of neovascular glaucoma when given prior to surgery — reducing the risk of hemorrhage and providing temporary reduction of IOP — but do not provide long-term IOP control, unless associated with panretinal photocoagulation.
- Trabeculectomy with antimetabolites, GDDs, or cyclophotocoagulation are options for the surgical management of neovascular glaucoma.
- Data on direct comparisons of different surgical options for neovascular glaucoma are limited, and there is currently no clearly superior surgical approach.
- With active neovascularisation, trabeculectomy should be avoided and a GDD should be considered.
- Success rates are lower, and intra- and postoperative complication rates are higher for neovascular glaucoma surgery than for POAG.
G. Glaucoma associated with aqueous misdirection
- Laser therapy in the form of peripheral anterior hyloidotomy and peripheral capsulotomy is indicated if medical therapy fails.
- Disruption of the peripheral anterior hyaloid and communication between vitreous and anterior chamber is required for complete resolution. It has a fair to good immediate success rate, but a high recurrence rate.
- In phakic eyes, phacoemulsification with intraocular lens implantation/lensectomy, combined with vitrectomy (pars plana or anterior approach), peripheral iridectomy, and zonulo-capsulo-hyloidectomy is recommended.
- In pseudophakic eyes, vitrectomy (pars plana or anterior approach) with peripheral iridectomy and capsulotomy or vitrectomy (pars plana or anterior approach) combined with peripheral iridectomy and zonulo-capsulo-hyloidectomy have a high success rate.
- Transscleral cyclophotocoagulation can be performed in eyes with media opacities and poor visual prognosis.
H. Glaucoma associated with keratoplasty
- Glaucoma post-keratoplasty is related to pre-existing glaucoma, indication for keratoplasty, surgical technique, inflammation, and use of steroids, among other factors.
- Secondary ocular hypertension is more frequent after penetrating keratoplasty than lamellar keratoplasty.
- Trabeculectomy with MMC is a good option when the conjunctiva is in good health.
- GDDs have good success rates in terms of IOP control, but may lead to higher rates of graft failure, often from tube touch.
- Cyclodestructive procedures may be used when other choices fail or are not recommended due to the condition of the eye.
- Any surgical procedure has to take into consideration both IOP control and graft survival.
- To avoid tube touch of the cornea, consideration should be given to placing the tube in the ciliary sulcus in the pseudophakic eye.
I. Glaucoma following vitreoretinal surgery
- When incisional surgery is needed, scarring of the conjunctiva may preclude the indication of a trabeculectomy. A GDD may be indicated, although its insertion may be a challenge for the surgeon in the presence of a buckle.
- GDDs may be placed over, posterior, next to, or within the encapsulation of the buckle.
- In eyes with silicone oil, the iridotomy or iridectomy should be performed at the 6 o’clock position.
- Laser iridotomy may be required if a pupillary block is present.
- If incisional surgery is needed, a GDD may be preferred.
- In the presence of silicone oil, the device is inserted inferiorly and the tube is placed inferiorly in the anterior chamber.
J. Lens-related glaucoma
- The treatment of any glaucoma associated with the lens is lens extraction. Glaucoma surgery can be added if necessary.
- Open-angle, lens-related glaucoma may be due to leakage of lens proteins through the capsule in a hypermature cataract (phacolytic), obstruction of the meshwork by lens fragments after cataract surgery, trauma or laser capsulotomy (lens-particle), or hypersensitivity to own lens protein following surgery or trauma (phacoantigenic).
- Cataract extraction or surgical removal of residual lens material should be performed with irrigation/aspiration and/or vitrectomy if medical treatment does not succeed to reduce the IOP and/or inflammation.
- Trabeculectomy may be considered in patients with lens-related glaucoma not controlled after the surgical removal of the lens or residual lens material.
K. Glaucoma due to elevated episcleral venous pressure
- Incisional surgery is often needed to reduce IOP.
- Initial treatment should be directed to the cause of the elevated episcleral venous pressure, when possible.
- Care should be taken to prevent hypotony intra- and postoperatively.
- The role of prophylactic sclerotomies to prevent suprachoroidal effusion and hemorrhage is controversial and requires further evaluation.
L. Glaucoma secondary to sustained, elevated IOP related to intravitreal injections of anti-VEGF
- IOP may be elevated after intravitreal injections of anti-VEGF, but usually diminishes after 30 to 60 minutes.
- Eyes with seven or more injections per year have an increased rate of glaucoma surgery.
- Often medical treatment is successful in controlling the IOP. However, surgical interventions have been reported when medical treatment was insufficient.
- Reports of surgical management are scarce and include laser trabeculoplasty, trabeculectomy, and GDDs.
M. Glaucoma secondary to iridocorneal endothelial syndrome
- Although trabeculectomy with MMC and GDDs have good initial results, other surgeries may be needed.
- Insertion of the tube in the sulcus or, when possible, in the vitreous cavity has been recommended to decrease the risk of corneal decompensation.
- If there are broad-based peripheral anterior synechiae, one should consider GDDs instead of trabeculectomy given the high risk of trabeculectomy failure.
- Ciliary ablation could be considered.