**4. Combined phacoemulsification–trabeculectomy**

#### **4.1. One–site versus two–site combined surgery**

**3.1. Anaesthetic considerations**

476 Glaucoma - Basic and Clinical Aspects

The combined surgery can be done under general anaesthesia, retro/peribulbar or sub-Tenon's block or with topical anaesthesia. All topical blocks are carried out with the patient lying on

We perform retrobulbar anaesthesia with a 23G needle. The inferior orbital rim is palpated through the skin at the junction of its middle and lateral thirds and the needle is inserted through the skin just above the rim with the patient looking straight ahead. It is then advanced parallel to the orbital floor and when the 4/5 of the length of the needle have been advanced it is slightly retracted and then redirected upwards and slightly nasally to enter the muscle cone. The plunge is retracted to check for blood reflux (blood reflux indicates that the needle may have entered a vessel and the mixture may be injected in the blood circulation). Five to 7 ml of the mixture are injected. Immediate drooping of the upper eyelid is an indication that the anaesthetic is being injected in the muscle cone. Retro/peribulbar block offers excellent anaesthesia and akinesia. The main complications are: globe perforation, retrobulbar haemor‐ rhage, central retinal artery occlusion (due to severe and untreated retrobulbar haemorrhage), and inadvertent brain stem brainstem anaesthesia due to puncture of the meningeal sheaths of the optic nerve and injection of the anaesthetic agents in the cerebrospinal fluid circulation. As the risk of globe rupture increases with the axial length of the eye it should be avoided in

The subtenon's block is done as follows: after topical anaesthesia with tetracaine drops, a speculum is inserted and the conjunctiva and Tenon's capsule are grasped with serrated forceps 5-7 mm from the limbus in the inferonasal or inferotemporal quadrant. A fold of conjunctiva is raised with the forceps and a small incision is made with Westcott scissors. A subtenon's canula is inserted through the incision and in closed contact with the globe it is advanced around and behind the eye. Three to 5 ml of the anaesthetic mixture are injected. If the canula is in the subtenon's space then there should not be any conjunctival chemosis. Presence of significant chemosis indicates that the canula lies in the subconjunctival rather than the subtenon's space. The surgeon should make a deeper incision through both conjunc‐ tiva and Tenon's capsule and guide the canula behind the globe in close contact with the globe. Subtenon's block also offers adequate anaesthesia but less good akinesia. The most common complications are: subconjunctival haemorrhage and conjunctival chemosis. The risk of globe

Topical anaesthesia is provided with tetracaine drops and Visthesia ampoules containing 2% lidocaine. It is the least invasive procedure but it does not offer akinesia. As the iris is not anaesthetized the patient may be more uncomfortable during the operation compared to the

General anaesthesia is seldom done and it is more suitable for claustrophobic patients or those who cannot lie flat and still for lengthy periods of time. In the case of general anaesthesia, retro/ peribulbal and subtenon's block the eye needs to be rotated downwards with the use of a

traction suture (described later) in order to expose the superior bulbar conjunctiva.

the operating bed. We use a mixture of 1:1 lidocaine 2% and bupivacaine 0.5%.

big eyes as well as in patients who receive anticoagulants.

perforation is minimized as the subtenon's canula is blunt.

above techniques especially during the iridectomy.

There is evidence that the two-site surgery offers slightly lower IOP (1-3 mmHg) than the onesite surgery [19-21]. The authors favor the two-site technique as it causes less damage to the area of filtration and subsequently less fibrosis with better chances for the survival of the trabeculectomy over time.

In the one-site technique the main incision of the phacoemulsification is done under the sclera flap and the cormeoscleral block excision is done at the site of the main incision. In the twosite approach the main incision of the phacoemulsification is done 90° away from the trabe‐ culectomy site and towards the temporal side of the eye.

In the surgeons' experience there was no significant difference in the IOP control between the two approaches.

#### **4.2. Limbus versus fornix conjunctival incision**

The limbus and fornix based conjunctival flaps are equally effective in lowering IOP [22-24]. However there is evidence that limbus based flaps are more prone to late hypotony and bleb infection [22,25]. Early bleb leaks were more common in the fornix based flaps [23,24].

#### **4.3. Aqueous humor dynamics in trabeculectomy**

The aim of the trabeculectomy is to bypass the conventional outflow pathway through the trabeculum and Schlemm's canal. The aqueous humor flows through an internal ostium at the level of the trabeculum under the scleral flap in the subconjunctiva/sub-Tenon's space with the formation of a filtering bleb. The scleral flap reduces the unrestricted flow of aqueous and can be secured to the sclera with fixed, releasable or adjustable sutures. A peripheral iridec‐ tomy at the site of the operation prevents the peripheral iris from obstructing the internal ostium. In some cases such as pseudophakic or myopic eyes where the peripheral iris rests well away from the ostium the peripheral iridectomy can be avoided. In this way the chances of hyphaema and significant postoperative inflammation are reduced.

#### **4.4. Risk factors in trabeculectomy**

The long term success of the trabeculectomy depends on several risk factors:

**•** *Black race*. The AGIS study showed weak evidence that Afro-Caribbean origin is a risk factor for failed trabeculectomy [26]. The results by Scott et al [27] agree with AGIS outcomes. However two studies by Sturmer et al [28] and Broadway et al [29] did not show statistically significant differences. The latter publication although it reports higher success rate in white patients it concludes that this difference was not statistically different. The authors speculate that trabeculectomy generally is considered to be less successful in black patients and the reason for that being their younger age during surgery and the fact that Tenon's capsule is capable of producing more intense inflammatory and subsequently fibrotic response.

**•** *Young age*. There is conflicting evidence in the literature as to whether young age is a risk factor for failed trabeculectomy. While the AGIS study [26] and Broadway et al [29] report that trabeculectomy has less favourable outcome overtime in young patients, other studies do not confirm these findings [28,30]

of lasik shields soaked in the antimetabolite solution under the conjunctiva and after the

Combined Cataract-Glaucoma Surgery http://dx.doi.org/10.5772/54808 479

Evidence has shown that the use of antimetabolites during surgery is associated with better IOP control [40,41]. On the other hand the use of antimetabolites has increased the incidence of side effects such as the postoperative hypotony, toxicity of the corneal epithelium, early and delayed bleb leaks, blebitis and endophthalmitis [42-44]. The antimetabolites can also be used

It is well established that the postoperative use of topical steroids is associated with better IOP control and less glaucoma medicines [45]. Corticosteroids can be used in a preemptive fashion before surgery in patients who were treated with antiglaucoma drops as these patients have lower success rate [46,47]. Research has shown that the instillation of corticosteroids and NSAIDs before surgery leads to better outcomes in terms of likelihood of bleb needling and postoperative use of antiglaucoma drops [48]. The injection of triamcinolone in the bleb or

Recently bevacizumab has been used intraoperatively instead of MMC in order to improve the success rate of the trabeculectomy but it has not proved to be superior to MMC [52,53].

The authors do not routinely prescribe topical corticosteroids before the antiglaucoma procedures unless the conjunctiva is markedly inflamed. In this case fluorometholone drops are given four times per day for one month before the operation. If the IOP is unacceptably high and there is high risk of expulsive haemorrhage tablets acetozolamide 250 mg 4 times per day are given for one or two days preoperatively. Additionally 200-400 ml of intravenous mannitol 20% are administered over 45-60 minutes on the morning before the operation. In theatre the eye is first anaesthetized with topical medication and then the local block is given according to the surgeon's preference. The skin around the eye is cleaned with iodine povidone solution 10%. A sterile drape is placed over the eye and a diluted 5% iodine solution is instilled

The following steps are the technique of choice of the authors for the combined phacoemulsi‐

**•** Blunt conjunctival and Tenon's dissection over a wide area. We try to limit limbal peritomy to three o' clock hours in order to achieve watertight closure with as few sutures as possible. Dissection is carried out posteriorly towards the insertion of the superior rectus muscle

on the eye and conjunctival fornices to achieve asepsis of the ocular surface.

**•** 7/0 Vicryl corneal traction suture 4 mm from the limbus (optional)

formation of the scleral flap.

*4.5.3. Anti–VEGF*

**4.6. Pre–operative preparation**

**4.7. Surgical technique**

fication-trabeculectomy procedure:

postoperatively with bleb needling in cases of failing blebs.

*4.5.2. Corticosteroids and non–steroidal anti–inflammatory drugs (NSAIDs)*

behind the globe seems beneficial in terms of IOP control [49-51]


#### **4.5. Antifibrotic agents**

#### *4.5.1. Antimetabolites*

Despite the initial success of the trabeculectomy clinical experience has shown that the operation tends to fail over time. This is due to the postoperative inflammation and the resulting formation of scar tissue at the site of the operation especially in the subconjunctival space. In order to improve the success of the operation surgeons resort to the use of antime‐ tabolites namely mitomycin C (MMC) and 5-fluorouracil (5-FU) [38]. They both inhibit fibroblast proliferation: 5-FU is antagonizes pyrimidine activity and inhibits DNA synthesis and thus suppresses fibroblast activity and inhibits epithelial cell proliferation while mitomy‐ cin C which is an alkylating agent interferes with all phases of cell cycle and prevents fibroblast and endothelial cell replication. MMC is more potent and has a more lasting in vivo effect than 5-FU. They can be used both intraoperatively and postoperatively. When used during surgery MMC was found to be slightly more effective than 5-FU with comparable rate of side effects [39]. The intraoperative dose of 5-FU is 0.1 ml of a 50mg/ml solution for 5 minutes. MMC has been used in varying concentration (0.2-0.4mg/ml) and application time (2-5 minutes) de‐ pending on the severity of glaucoma and presence of risk factors. The authors prefer the use of lasik shields soaked in the antimetabolite solution under the conjunctiva and after the formation of the scleral flap.

Evidence has shown that the use of antimetabolites during surgery is associated with better IOP control [40,41]. On the other hand the use of antimetabolites has increased the incidence of side effects such as the postoperative hypotony, toxicity of the corneal epithelium, early and delayed bleb leaks, blebitis and endophthalmitis [42-44]. The antimetabolites can also be used postoperatively with bleb needling in cases of failing blebs.

#### *4.5.2. Corticosteroids and non–steroidal anti–inflammatory drugs (NSAIDs)*

It is well established that the postoperative use of topical steroids is associated with better IOP control and less glaucoma medicines [45]. Corticosteroids can be used in a preemptive fashion before surgery in patients who were treated with antiglaucoma drops as these patients have lower success rate [46,47]. Research has shown that the instillation of corticosteroids and NSAIDs before surgery leads to better outcomes in terms of likelihood of bleb needling and postoperative use of antiglaucoma drops [48]. The injection of triamcinolone in the bleb or behind the globe seems beneficial in terms of IOP control [49-51]

### *4.5.3. Anti–VEGF*

**•** *Young age*. There is conflicting evidence in the literature as to whether young age is a risk factor for failed trabeculectomy. While the AGIS study [26] and Broadway et al [29] report that trabeculectomy has less favourable outcome overtime in young patients, other studies

**•** *Combined procedure*. Research shows that combined phacotrabeculectomy produces lower

**•** *Long term treatment with multiple antiglaucoma drops*. There is strong evidence that long term treatment with antiglaucoma drops increases the number of inflammatory cells [31] and

**•** *Previous operations*. Subconjunctival scarring from previous operations can limit the success of the trabeculectomy. The AGIS study [26] did not identify repeat trabeculectomies (second or third trabeculectomy) as a risk factor for failure. A possible explanation may be that repeat trabeculectomies were done with the use of antifibrotic agents. Indeed Broadway et al [33] reported that trabeculectomies following conjunctival incisional operations were more likely to fail compared to primary trabeculectomies More recent studies confirmed that repeat trabeculectomies augmented by intraoperative use of mitonycin C is an effective

**•** *Secondary glaucomas (traumatic, uveitic, aphakic, rubeotic)*. Mietz et al [36] found that the neovascular, traumatic and uveitic glaucoma had the worst prognosis regarding trabecu‐

**•** *Diabetes*. The AGIS study as well as a study by Hugkulstone et al [37] found that diabetes is

Despite the initial success of the trabeculectomy clinical experience has shown that the operation tends to fail over time. This is due to the postoperative inflammation and the resulting formation of scar tissue at the site of the operation especially in the subconjunctival space. In order to improve the success of the operation surgeons resort to the use of antime‐ tabolites namely mitomycin C (MMC) and 5-fluorouracil (5-FU) [38]. They both inhibit fibroblast proliferation: 5-FU is antagonizes pyrimidine activity and inhibits DNA synthesis and thus suppresses fibroblast activity and inhibits epithelial cell proliferation while mitomy‐ cin C which is an alkylating agent interferes with all phases of cell cycle and prevents fibroblast and endothelial cell replication. MMC is more potent and has a more lasting in vivo effect than 5-FU. They can be used both intraoperatively and postoperatively. When used during surgery MMC was found to be slightly more effective than 5-FU with comparable rate of side effects [39]. The intraoperative dose of 5-FU is 0.1 ml of a 50mg/ml solution for 5 minutes. MMC has been used in varying concentration (0.2-0.4mg/ml) and application time (2-5 minutes) de‐ pending on the severity of glaucoma and presence of risk factors. The authors prefer the use

hypotensive effect than trabeculectomy alone (discussed later)

do not confirm these findings [28,30]

478 Glaucoma - Basic and Clinical Aspects

decreases the success of trabeculectomy [32]

procedure for IOP control [34,35]

a risk factor for failed trabeculectomy

lectomy survival.

**4.5. Antifibrotic agents**

*4.5.1. Antimetabolites*

Recently bevacizumab has been used intraoperatively instead of MMC in order to improve the success rate of the trabeculectomy but it has not proved to be superior to MMC [52,53].

#### **4.6. Pre–operative preparation**

The authors do not routinely prescribe topical corticosteroids before the antiglaucoma procedures unless the conjunctiva is markedly inflamed. In this case fluorometholone drops are given four times per day for one month before the operation. If the IOP is unacceptably high and there is high risk of expulsive haemorrhage tablets acetozolamide 250 mg 4 times per day are given for one or two days preoperatively. Additionally 200-400 ml of intravenous mannitol 20% are administered over 45-60 minutes on the morning before the operation. In theatre the eye is first anaesthetized with topical medication and then the local block is given according to the surgeon's preference. The skin around the eye is cleaned with iodine povidone solution 10%. A sterile drape is placed over the eye and a diluted 5% iodine solution is instilled on the eye and conjunctival fornices to achieve asepsis of the ocular surface.

### **4.7. Surgical technique**

The following steps are the technique of choice of the authors for the combined phacoemulsi‐ fication-trabeculectomy procedure:


**Figure 1.** Technique for inserting a releasable suture. A: first entry of suture just behind the limbus, B: first exit of su‐ ture into clear cornea just in front of the limbus, C: second entry of suture into clear cornea just in front of the limbus. The suture runs through the thickness of the sclera flap and exits at point D, E:third entry point of suture through the full thickness of the sclera flap and exits at point G in the sclera. The free end of the suture (arrow) is tied with 4 throws to the loop F. The suture is not locked. It can be removed by pulling the small loop between points B and C. It is important that the suture runs at an angle of 45° between points E and G in order to pull the flap both laterally and

Combined Cataract-Glaucoma Surgery http://dx.doi.org/10.5772/54808 481

Cyclopentolate drops 1% are given 3 times per day for 2-3 weeks in order to reduce the intraocular inflammation and reduce the incidence of aqueous misdirection. Drops dexame‐ thasone 0.1% and tobramycin 0.3% 8 times per day are gives in the immediate postoperative period. The frequency is reduced according to the postoperative course of the operation. If the there is anterior chamber or conjunctival inflammation the drops should be given more frequently and for longer periods of time. While the antibiotic drops can be discontinued after 4 weeks, steroids may need to be continued for 6 months at a low frequency (e.g.: 1 drop/day or on alternate days). If there are signs of subconjunctival scarring (dilated vessels that do not run smoothly on the conjunctiva but seem distorted along their course), subconjunctival dexamethasone 0.1 ml (8mg in 2ml solution) and 5FU 0.1 ml (10 ml solution containing 500 mg) injections can be administered not more frequently than weekly injections. The injections are done just behind the bleb. The insertion of the needle should be at least 5mm away from

Needling may be needed if the there is scarring. We perform the needling at the slit lamp as follows: the eye is anaesthetized with tetracaine 1% and Visthesia ampoules. Asepsis of

the bleb in order to avoid bleb leakage after the needle is withdrawn.

posteriorly.

**4.8. Postoperative management**


**Figure 1.** Technique for inserting a releasable suture. A: first entry of suture just behind the limbus, B: first exit of su‐ ture into clear cornea just in front of the limbus, C: second entry of suture into clear cornea just in front of the limbus. The suture runs through the thickness of the sclera flap and exits at point D, E:third entry point of suture through the full thickness of the sclera flap and exits at point G in the sclera. The free end of the suture (arrow) is tied with 4 throws to the loop F. The suture is not locked. It can be removed by pulling the small loop between points B and C. It is important that the suture runs at an angle of 45° between points E and G in order to pull the flap both laterally and posteriorly.

#### **4.8. Postoperative management**

**•** Scleral flap formation (4×4mm) at 50% of the sclera thickness. Initially we perform a sclera incision 4mm long 4mm behind the limbus. Scleral dissection is performed with a beveled crescent knife until the limbal vessels are reached. Then we perform the side cuts to create

**•** Application of MMC (0.2 mg/ml for 2-3 minutes) with the use of a few pieces of of a lasik shield arranged over a wide area under the conjunctiva. The edges of the conjunctiva are grasped with serrated forceps and are wiped with Weck-cell sponges in order to remove MMC. The presence of MMC at the cut edge of the conjunctiva may prevent wound closure

**•** The area of application of MMC is then irrigated with 20 ml of balanced salt solution

**•** 2.75 mm clear cornea phacoemulsification from a temporal approach with injectable

**•** Balanced salt solution (BSS) injection in the stroma or a 10/0 nylon suture at the site of the main incision of the phacoemulsification in order to encourage filtration though the scleral flap rather than the main incision. As BSS induced stromal oedema lasts for a very short

**•** Pre-placement of two 10/0 Nylon releasable sutures at the two corners of the flap (fig 1). We prefer to pre-place the sutures in order to reduce the period of hypotony during the creation

**•** Peripheral iridectomy (if needed). This step can be omitted in cases of highly myopic and pseudophakic in which case the iris lies quite posteriorly from the internal ostium

**•** Tying of the scleral flap releasable sutures (more sutures can be used according to the surgeon's discretion). This step is very critical as the surgeon checks the amount of aqueous flowing from the edges of the sclera flap. Ideally there should be some ''oozing'' only, after

**•** Conjunctival and Tenon's layer closure in one plane with 10/0 nylon sutures. Usually two sutures (one at each side of the limbal peritomy) are used and tied in a purse-string fashion. One or two horizontal mattress sutures are used between the first sutures. The conjunctival

**•** Triamcinolone or celectone chronodose injection subconjunctivally 0.1 ml behind the scleral flap at the end of the operation. 0.1 ml of gentamycin (solution of 80 mg in 2ml) is injected

period of time we prefer to close the main incision with a suture

**•** Excision of a corneoscleral block (internal ostium) with a Kelly punch.

BSS is slowly injected from side ports of the phacoemulsification

of the internal ostium and peripheral iridectomy

wound is then checked for leakage.

subconjunctivally in the lower fornix.

**•** Entry in the anterior chamber at the site of the scleral flap

the sclera flap.

480 Glaucoma - Basic and Clinical Aspects

and lead to postoperative leak.

intraocular lens insertion

**•** Bipolar cautery is kept to a minimum

Cyclopentolate drops 1% are given 3 times per day for 2-3 weeks in order to reduce the intraocular inflammation and reduce the incidence of aqueous misdirection. Drops dexame‐ thasone 0.1% and tobramycin 0.3% 8 times per day are gives in the immediate postoperative period. The frequency is reduced according to the postoperative course of the operation. If the there is anterior chamber or conjunctival inflammation the drops should be given more frequently and for longer periods of time. While the antibiotic drops can be discontinued after 4 weeks, steroids may need to be continued for 6 months at a low frequency (e.g.: 1 drop/day or on alternate days). If there are signs of subconjunctival scarring (dilated vessels that do not run smoothly on the conjunctiva but seem distorted along their course), subconjunctival dexamethasone 0.1 ml (8mg in 2ml solution) and 5FU 0.1 ml (10 ml solution containing 500 mg) injections can be administered not more frequently than weekly injections. The injections are done just behind the bleb. The insertion of the needle should be at least 5mm away from the bleb in order to avoid bleb leakage after the needle is withdrawn.

Needling may be needed if the there is scarring. We perform the needling at the slit lamp as follows: the eye is anaesthetized with tetracaine 1% and Visthesia ampoules. Asepsis of

the ocular surface is achieved with 5% iodine povidone solution. A 30G needle mounted on a insulin syringe containing BSS is inserted under the conjunctiva at least 5mm away from the bleb. BSS is slowly injected to lift the conjunctiva and the needle is directed towards the site of the bleb. Subconjunctival fibrosis is broken with sweeping move‐ ments of the needle. If the anterior chamber is to be entered a Hoskins lens is used to deturgess the conjunctiva. The tip of the needle is used to cut the fibrous tissue around the edges of the sclera flap and lift the flap. The needle then enters the anterior chamber through the internal ostium. A mixture of 0.1 ml dexamethasone and 0.1 ml 5 FU is injected through the same entering point behind the bleb.

● Resistance at the level of sclerostomy

● Resistance at the level of scleral flap

● Resistance at the level of conjunctiva/Tenon's layer

● High IOP with shallow anterior chamber

through sclerostomies in the case of kissing choroidals.

vitreous face, vitrectomy (it disrupts the anterior hyaloids)

Risk factors: male gender, young age myopia, MMC [56-58]

● Low IOP with deep/shallow anterior chamber

● Blood. Management: topical steroids, ocular massage, intracameral tissue plasminogen activator [55],

Combined Cataract-Glaucoma Surgery http://dx.doi.org/10.5772/54808 483

● Tight sutures. Management: ocular massage, argon laser suturolysis, removal of releasable sutures

● Blood. Management: topical steroids, ocular massage, intracameral tissue plasminogen activator, aspiration in

Diffuse scar tissue formation or formation of encapsulated bleb (Tenon's cyst). Management. Topical steroids,

There are several signs that will help the clinician to identify the site of obstruction. Gonioscopy will reveal the causes of the obstruction at the level of the internal ostium. Resistance at the level of the sclera flap will produce a very low bleb with no intraepithelial cysts (which are a sign of ample aqueous flow). Resistance at the subconjunctival level with diffuse scar formation will produce a low or slightly elevated bleb with microcysts formation at some areas of the bleb. The conjunctival vessels may be dilated (due to inflammation and subsequent scar tissue deposition) and they can appear ''kinked'' at some points along their course. Tenon's cyst is a high dome shaped, localized and avascular bleb without microcysts. There may be some engorged vessels on its surface. They typically appear 2-6 weeks after

● Pupillary block. Management: YAG laser/surgical iridectomy. The setting that we use for YAG laser iridectmy

● Suprachoroidal haemorrhage. Management: cycloplegia, topical and systemic steroids, evacuation of blood

● Aqueous misdirection. Management: mydriatics, aqueous suppressants, YAG laser disruption of the anterior

● Overfiltration. Management: pressure patch, large diameter contact lens, cryotherapy, suturing of the scleral

are: single or double pulsed shots, defocused posteriorly with starting energy at 5 mJoules

● Iris: retraction of iris tissue with argon laser, removal of iris in theatre. ● Vitreous: YAG-laser to release vitreous, removal of vitreous in theatre.

bleb needling with 5-FU or MMC injection, scar tissue removal in theatre.

Causes:

Causes:

theatre.

Causes

surgery.

Causes

Causes

flap

aspiration in theatre.

Argon laser suturolysis can be performed when the sclera flap sutures are tight and obstruct aqueous outflow. The settings are 50µ spot size, 150-250 mW power, 0.1 seconds exposure time through a Hoskins lens.

#### **4.9. Outcomes**

There is evidence that combined cataract-glaucoma surgery produces slightly lower hypoten‐ sive effect than trabeculectomy alone. [54]

#### **4.10. Complications**

The complications of the combined cataract-glaucoma surgery include those of phacoemulsi‐ fication and those of trabeculectomy. In this chapter we analyze the most common complica‐ tions of trabeculectomy. It should be noted that a complicated cataract surgery can compromise the success of the trabeculectomy mainly due to the presence of intense inflammation, vitreous or blood in the anterior chamber.

#### *Intraoperative:*


Mechanism: bleeding from the peripheral iridectomy

Management: none if it is minimal, aspiration of blood if it stains the cornea or the IOP is high ("/>30 mmHg for 5 days or "/>50 mmHg for two days)

#### *Postoperative*

The postoperative complications can broadly be divided in early (which occur 6 weeks after surgery) and late (which occur after 6 weeks from surgery)

*Early postoperative:*


● Resistance at the level of sclerostomy

Causes:

the ocular surface is achieved with 5% iodine povidone solution. A 30G needle mounted on a insulin syringe containing BSS is inserted under the conjunctiva at least 5mm away from the bleb. BSS is slowly injected to lift the conjunctiva and the needle is directed towards the site of the bleb. Subconjunctival fibrosis is broken with sweeping move‐ ments of the needle. If the anterior chamber is to be entered a Hoskins lens is used to deturgess the conjunctiva. The tip of the needle is used to cut the fibrous tissue around the edges of the sclera flap and lift the flap. The needle then enters the anterior chamber through the internal ostium. A mixture of 0.1 ml dexamethasone and 0.1 ml 5 FU is injected

Argon laser suturolysis can be performed when the sclera flap sutures are tight and obstruct aqueous outflow. The settings are 50µ spot size, 150-250 mW power, 0.1 seconds exposure time

There is evidence that combined cataract-glaucoma surgery produces slightly lower hypoten‐

The complications of the combined cataract-glaucoma surgery include those of phacoemulsi‐ fication and those of trabeculectomy. In this chapter we analyze the most common complica‐ tions of trabeculectomy. It should be noted that a complicated cataract surgery can compromise the success of the trabeculectomy mainly due to the presence of intense inflammation, vitreous

Management: none if it is minimal, aspiration of blood if it stains the cornea or the IOP is high ("/>30 mmHg for 5

The postoperative complications can broadly be divided in early (which occur 6 weeks after surgery) and late (which

● Retained viscoelestic. Management: observation, antiglaucoma drops. If IOP is very high it can be aspirated in

● Steroid response. Management: antiglaucoma drops, non-steroidal anti-inflammatory drugs

through the same entering point behind the bleb.

sive effect than trabeculectomy alone. [54]

or blood in the anterior chamber.

days or "/>50 mmHg for two days)

● High IOP with deep anterior chamber

occur after 6 weeks from surgery)

● Conjunctival buttonhole. Management: suturing with 10/0 nylon

Mechanism: bleeding from the peripheral iridectomy

through a Hoskins lens.

482 Glaucoma - Basic and Clinical Aspects

**4.9. Outcomes**

**4.10. Complications**

*Intraoperative:*

*Postoperative*

*Early postoperative:*

theatre

● Hyphaema

● Blood. Management: topical steroids, ocular massage, intracameral tissue plasminogen activator [55], aspiration in theatre.


Causes:


#### Causes

Diffuse scar tissue formation or formation of encapsulated bleb (Tenon's cyst). Management. Topical steroids, bleb needling with 5-FU or MMC injection, scar tissue removal in theatre.

There are several signs that will help the clinician to identify the site of obstruction. Gonioscopy will reveal the causes of the obstruction at the level of the internal ostium. Resistance at the level of the sclera flap will produce a very low bleb with no intraepithelial cysts (which are a sign of ample aqueous flow). Resistance at the subconjunctival level with diffuse scar formation will produce a low or slightly elevated bleb with microcysts formation at some areas of the bleb. The conjunctival vessels may be dilated (due to inflammation and subsequent scar tissue deposition) and they can appear ''kinked'' at some points along their course. Tenon's cyst is a high dome shaped, localized and avascular bleb without microcysts. There may be some engorged vessels on its surface. They typically appear 2-6 weeks after surgery.

● High IOP with shallow anterior chamber

Causes


Causes

● Overfiltration. Management: pressure patch, large diameter contact lens, cryotherapy, suturing of the scleral flap

● Bleb leak. Management: pressure patch, large diameter contact lens, cyanoacrylate glue, autologous blood, suturing of the conjunctiva

lostomy in which the aqueous is directed in the enlarged SC and the tight suturing of the scleral

Combined Cataract-Glaucoma Surgery http://dx.doi.org/10.5772/54808 485

**Figure 2.** Aqueous in the subconjunctival space flowing DS. A: bleb wall, B: bleb cavity (courtesy of Prof Kozobolis).

The main indication for combined phaco-NPGS is the primary open and secondary open angle

Non penetrating glaucoma surgery is useful in open angle glaucomas but should be avoided in closed angle glaucomas as the peripheral iris in these cases blocks the TDM and obstructs the percolation of aqueous. NPGS has also been used in congenital and juvenile glaucomas

The adjunctive use of MMC in NPGS showed better hypotensive effect at the cost of higher

The following steps are the technique of choice of the authors for the combined phacoemulsi‐

**•** Conjunctival and Tenon's dissection. As for trabeculectomy we try to keep the limbal

rate of complications (thin avascular blebs, transconjunctival oozing) [64,65].

**•** 7/0 Vicryl corneal traction suture 4 mm from the limbus (optional)

The same principles apply for the pre-operative preparation as for trabeculectomy

flap is considered as a crucial part of the surgical procedure.

glaucomas in the presence of visually debilitating cataract.

**5.2. Indications**

[61-63].

**5.3. Contraindications**

**5.4. Antimetabolites**

**5.5. Pre–operative preparation**

peritomy as small as possible

**5.6. Surgical technique**

fication-DS procedure:

● Aqueous shutdown. Management: topical steroids

● Cyclodialysis cleft. Management: mydriatics, laser photocoagulation/cryotherapy/suturing of the cleft with 7/0 or 8/0 nylon sutures as the 10/0 nylon may not be strong enough the hold the cleft closed if the IOP increases dramatically in the early postoperative period.

In the presence of a very shallow anterior chamber management should include reformation of the anterior chamber with viscoelastic and if there are large choroidal effusions which touch each other (kissing choroidals) then they must be drained via sclerostomies. If the choroidal effusions are not touching each other they can be conservatively managed with cycloplegics, topical steroids. Periocular and oral steroids can also be given

*Late postoperative*

● Late bleb failure

Causes: scarring. Management: bleb needling, injection of 5-FU/MMC, trabeculectomy revision/redo, glaucoma drainage implants

● Late bleb leak

Cause: thin walled bleb. Risk factors: antimetabolites. Management: aqueous suppressants, large diameter bandage contact lens, autologous serum, cyanoacrylic glue, autologous blood injection in the bleb, conjunctival excision with conjunctival advancement or flap

● Blebitis and bleb related endophthalmitis

Causes: infection of the bleb by various micro-organisms.

Risk factors: thin walled blebs, bleb leaks, exposed sutures, antimetabolites, blepharitis, conjunctivitis, nasolacrimal duct obstruction, diabetes.

Management: sample cultures, broad-spectrum antibiotics (for blebitis), vitreous tap, intravitreal antibiotics ± vitrectomy (for bleb related endophthalmitis)

● Persistent hypotony due to MMC effect (toxic effect on the ciliary body) [59,60]
