Acta Ophthalmologica 2015
Review Article The use of endoscopic cyclophotocoagulation for moderate to advanced glaucoma Kevin Kaplowitz, Andrew Kuei, Britany Klenofsky, Azin Abazari and Robert Honkanen Department of Ophthalmology, Stony Brook University Medical Center, Stony Brook, New York, USA
ABSTRACT. Endoscopic Cyclophotocoagulation (ECP) is a glaucoma surgery designed to reduce the intraocular pressure (IOP) by partially ablating the ciliary processes to decrease aqueous humour production and secretion. The aim of this paper is to review the literature regarding the background, indications and results of the surgery. Although there are case reports of visually devastating complications, including persistent hypotony and phthisis, the use of ECP is often reported in eyes with advanced diseases. When compared with both trabeculectomy and aqueous shunt implantation, the visual outcomes were better with ECP while the IOP outcomes were very similar. The evidence supports ECP as a very effective surgical option in recalcitrant glaucoma while some evidence supports its safety for use as a primary procedure. Key words: diode – endoscopic cyclophotocoagulation – glaucoma – laser – transscleral
Acta Ophthalmol. 2015: 93: 395–401 ª 2014 Acta Ophthalmologica Scandinavica Foundation. Published by John Wiley & Sons Ltd
doi: 10.1111/aos.12529
Introduction Cyclophotocoagulation was first introduced in the early 1970s as a last-line surgery to lower intraocular pressure (IOP). Unlike standard glaucoma surgery such as trabeculectomy or aqueous drainage devices, cyclophotocoagulation aims to reduce the IOP by reducing aqueous production. Early iterations of cyclophotocoagulation delivered through a contact or non-contact approach were limited to patients with end-stage glaucoma. This was due to the unpredictability and complications such as hypotony and phthisis (Francis et al. 2014). In 1992, the first results were reported on a novel technique of ciliary body photocoagulation delivered under direct visualization through endoscopy (Uram 1992). The aim of this paper is to review the published English literature to discuss the indications, results and
complications of endoscopic cyclophotocoagulation (ECP).
Mechanism of Action Cyclophotocoagulation uses focused laser to ablate the ciliary body processes, a technique refined by transscleral delivery with a contact probe. The most commonly used laser is a semiconductor diode laser emitting at 810 nm (Chen et al. 1999). The diode laser causes coagulative necrosis of the ciliary body epithelium (pigmented and non-pigmented) as well as the stroma (Assia et al. 1991). This leads to hyalinization of the scleral collagen, disruption of the ciliary body epithelium and ciliary process atrophy (Cavens et al. 2012). The atrophy of the ciliary process decreases the amount of aqueous inflow, and this is thought to be the most important explanation of the IOP
decrease seen after the procedure. Another IOP-lowering effect may be increased uveoscleral outflow through the areas of damaged tissue (Coleman et al. 1985; Bloom & Dharmaraj 2006). Like the trans-scleral procedure, the endoscopic system uses a diode laser that emits pulsed continuous energy (Lin 2002). A rabbit study showed that following either trans-scleral or endoscopic diode laser, there was almost no blood flow on fluorescein angiography through the treated ciliary processes (Lin et al. 2006). The effect was seen immediately after laser application with little change until 1 month later. At that point, only the endoscopic group displayed some areas of reperfusion. An exudative membrane extending to the pars plana was only seen following trans-scleral laser. Otherwise, similar histological effects were observed with both lasers, namely coagulative necrosis of the stroma and pigmented and nonpigmented ciliary body epithelial cells, leading to ciliary process atrophy.
Indications
Trans-scleral cyclophotocoagulation has traditionally been reserved for more advanced cases of glaucoma because of the higher risk of sightthreatening complications as compared with penetrating surgery (Iliev & Gerber 2007). ECP has been used to treat primary open-angle glaucoma (POAG), pigmentary and neovascular glaucoma (NVG), chronic angle closure glaucoma (CACG), postpenetrating keratoplasty (Murthy et al. 2009), iridocorneal syndrome (Clement et al. 2013), as well as congenital (Lima et al.
395
Acta Ophthalmologica 2015
2004), uveitic (Lima et al. 2004), anglerecession (Lima et al. 2004) and normal-tension glaucoma (Kahook et al. 2007a). Absolute contraindications have not been reported. Technique
The endoscopic diode laser unit manufactured by Endo Optiks (Little Silver, NJ, USA) has a 670-nm laser to provide the aiming beam, a 175 W xenon light source and an endoscope built into the diode laser probe (Jacobi & Dietlein 2000; Lin 2002). Similar to the trans-scleral diode laser, the laser is triggered by a foot pedal that fires the laser as long as the pedal is depressed, up to 9.99 s. The maximum power setting is 1.2 W (Carter et al. 2007). Preoperative considerations are similar to phacoemulsification, although retrobulbar anaesthesia is frequently employed (Chen et al. 1997; Francis et al. 2011). The probe can be inserted through a temporal incision made either at the limbus or at the pars plana 3.5-mm posterior to the limbus (Lima et al. 2004). With the pars plana approach, a vitrectomy is usually performed before inserting the probe through the sclerostomy, (Murthy et al. 2009) although cases have been reported without a vitrectomy (Raizada & Al Sabti 2009). With the limbal approach, a 2.5-mm clear-corneal incision can be made (Francis et al. 2014). If it is being performed in conjunction with phacoemulsification, ECP is performed after the intraocular lens is placed. The anterior chamber as well as the ciliary sulcus is further expanded with cohesive viscoelastic. The probe is inserted under microscopic view and advanced to the pupil. At this point, attention should be turned towards the camera monitor and the probe is
advanced towards the ciliary body until 6–8 processes fill the view (Francis et al. 2014). This correlates with a 2-mm separation between the probe tip and the ciliary process, which has been measured to provide the delivered laser energy as close as possible to the power displayed on the readout (Yu et al. 2008). A typical power setting is 500 mW for 0.5–2 s (Chen et al. 1997). The aiming beam is directed at the centre of a process, and the laser is fired along the entire length of the process until it whitens and tissue shrinkage is noted. Scleral depression can be done to ensure the entire length of the ciliary process is visualized and treated (Lima et al. 2004). The circumference of treatment has varied from 90 (Uram 1992) to 360 (Francis et al. 2014) degrees (see the results section for further details). With a single incision, it is possible to view and treat up to 300 degrees (Kahook et al. 2007a). Making a second incision up to 180 degrees away allows for 360 degrees of treatment. At the end of the case, the viscoelastic should be aspirated out and the wounds hydrated. Dexamethasone should be injected subconjunctivally (Lima et al. 2004). Postoperatively, a topical fluoroquinolone, prednisolone acetate 1% and non-steroidal anti-inflammatory can be given four times a day (Kahook et al. 2007a). The IOP decrease may not be expected immediately, especially with retained viscoelastic which was injected in the ciliary sulcus (Netland et al. 2007). A small case series of ECP performed with an AC maintainer and iris hooks in place of viscoelastic had a significantly lower IOP on the first postoperative day (Kahook et al. 2007b). The patient’s current glaucoma medications are often continued into
the postoperative visits until the IOPlowering effect is observed (Francis et al. 2011). Many studies did not report the IOP or number of medications on the first postoperative day. However, in one study, the IOP on postoperative day 1 (off glaucoma medications) was only reduced by an average of 14% from baseline (Yip et al. 2009).
Results ECP is frequently reported for use in one of two different subsets: mild POAG or advanced secondary glaucomas. Only a single study (n = 63, retrospective) stratified their results between POAG and secondary glaucomas. First, they separately analysed POAG versus any other type of glaucoma and found that the POAG group had a mean 22% decrease from a baseline of 21 mmHg, while other glaucomas had a 29% decrease from a baseline of 22 mmHg. They did not report whether the difference between the two groups was statistically significant. They also re-divided their cases into primary surgery versus cases with a history of failed glaucoma surgery prior to ECP. The surgically naive group had a mean 30% decrease from a baseline of 22 mmHg, while those with previous surgery had a 17% decrease from a baseline of 20 mmHg. Again, it was not noted whether the difference reached statistical significance. Based on the available data, we have calculated an overall average for POAG (Table 1) versus secondary glaucomas (Table 2). In the POAG studies, most of which were categorized as mild, the mean IOP decrease ranged from 3.9 mmHg (Yip et al. 2009) to 10.9 mmHg (Lima et al. 2010) or 18% (Yip et al. 2009) –47% (Lima et al.
Table 1. Review of published results for endoscopic cyclophotocoagulation in primary open-angle glaucoma.
First author
Study type
Gayton (Gayton et al. 1999)
Prospective, randomized Retrospective Retrospective Retrospective Retrospective Retrospective Retrospective
Kahook (Kahook et al. 2007b) Kahook (Kahook et al. 2007a) Yip (Yip et al. 2009) Lima (Lima et al. 2010) Lindfield (Lindfield et al. 2012) Clement (Clement et al. 2013)
396
# eyes in the ECP group 29 15 40 29 368 56 63
Mean baseline IOP in mmHg 24.8 22.7 (mean of all patients) 24 (mean of all patients) 21.8 23.1 21.5 21.1
Final mean decrease in IOP, mmHg (%) 8.8 (29%) 6.3 9.5 3.9 10.9 7.1 5
(28%) (40%) (18%) (47%) (33%) (24%)
Mean # decrease in medication 0.06 Not reported 1.3 0.8 1.1 +0.06 (increased) 1.2
Study length 24 months 1 month 6 months 24 months 24 months 24 months 12 months
Acta Ophthalmologica 2015
Table 2. Review of published results for endoscopic cyclophotocoagulation in secondary glaucomas.
First author
Study type
Uram (Uram 1992)
Retrospective
Chen (Chen et al. 1997) Lima (Lima et al. 2004) Carter (Carter et al. 2007) Lima (Lima et al. 2009) Murthy (Murthy et al. 2009) Francis (Francis et al. 2011)
Retrospective Prospective Retrospective Retrospective Prospective Prospective
2010), where the mean IOP decrease was 7 mmHg or 31%. In the advanced secondary glaucoma group, the IOP decreased from 7 mmHg (Francis et al. 2011) to 28 mmHg (Uram 1992) or 26% (Francis et al. 2011) –68% (Lima et al. 2009), yielding a mean 18 mmHg or 50% IOP decrease. The first reported results of ECP came in 1992 after use in 10 patients with neovascular glaucoma who were followed for 6–11 months after 90–180 degrees of treatment (Uram 1992). The mean IOP fell 65% from a baseline of 44 mmHg. Six of 10 cases maintained an IOP < 21 off of all medications. The maximum IOP decrease was seen after 6 weeks. A retrospective review of 68 cases showed that the IOP was lowered by 34% from a baseline of 28 mmHg with an average follow-up period of 13 months (Chen et al. 1997). The number of medications decreased from 3 to 2. While only 74% of cases had a 20% IOP decrease from baseline, 94% of cases had an IOP ≤21 at 1 year and 82% did so at 2 years. A large prospective series of 45 cases, where the most common diagnosis was neovascular glaucoma, showed a 61% decrease in IOP from a baseline of 33 mmHg on 1.4 less medications after 21 months (Murthy et al. 2009). The two largest studies were done by the same author. The first reviewed 368 cases of combined phacoemulsification and ECP for POAG (Lima et al. 2010). The IOP decreased by 47% from a baseline of 23 mmHg after both 1 and 2 years, on 1.1 fewer medications. The most common complication was an IOP spike, which they observed in 14% of cases (although they measured the IOP only 3 hr after surgery). At 2 years, an IOP between 5–21 mmHg was achieved with medications in 91% of patients and without any medications in 56% of
# eyes in the ECP group
Mean baseline IOP in mmHg
Final mean decrease in IOP, mmHg (%)
Mean # decrease in medication
10
43.6
28.3 (65%)
68 34 34 539 45 25
27.7 41.6 32.6 38.1 32.6 24
10.7 27.5 9.7 26 19.8 7
Only specified 66% stopped acetazolamide 1 1 0 2 1.4 1.2
(34%) (66%) (30%) (68%) (61%) (26%)
cases. Persistent vision loss occurred in only 1%, from CME. The largest published study was a retrospective review of 539 patients who were followed for an average of 7.4 years (Lima et al. 2009). The laser was applied for 210 degrees and 50% of the patients had either POAG or CACG, with the third most common diagnosis being neovascular glaucoma (17%). The mean IOP decreased 68% from a mean baseline of 38 mmHg on 2 fewer medications after 5 years. The IOP was between 6– 21 mmHg in 93% of cases after 1 year and in 79% after 5 years. The average number of medications at 5 years was 1.9, and only 22% of cases were off medications. The vision was stable or improved in 95%. ECP has been used following failed aqueous shunts. A prospective study (n = 25) found that ECP lowered the IOP by 26% from a baseline of 24 mmHg 2 years after the ECP (Francis et al. 2011). The number of medications went from 3.2 at baseline, to 1.5 at 1 year, but then increased to 2 at 2 years. Defining success as an IOP ≤21, along with either a decrease from baseline IOP by 3 mmHg or a decrease in the number of medications, the success rate at 2 years was 88%. ECP was performed for paediatric aphakic glaucoma in a group of 34 eyes with an average age of 4.2 years (Carter et al. 2007). The IOP decreased by 30% from a baseline of 32.6 mmHg after 44 months, with no change in number of medications. Defining success as IOP
Review Article The use of endoscopic cyclophotocoagulation for moderate to advanced glaucoma Kevin Kaplowitz, Andrew Kuei, Britany Klenofsky, Azin Abazari and Robert Honkanen Department of Ophthalmology, Stony Brook University Medical Center, Stony Brook, New York, USA
ABSTRACT. Endoscopic Cyclophotocoagulation (ECP) is a glaucoma surgery designed to reduce the intraocular pressure (IOP) by partially ablating the ciliary processes to decrease aqueous humour production and secretion. The aim of this paper is to review the literature regarding the background, indications and results of the surgery. Although there are case reports of visually devastating complications, including persistent hypotony and phthisis, the use of ECP is often reported in eyes with advanced diseases. When compared with both trabeculectomy and aqueous shunt implantation, the visual outcomes were better with ECP while the IOP outcomes were very similar. The evidence supports ECP as a very effective surgical option in recalcitrant glaucoma while some evidence supports its safety for use as a primary procedure. Key words: diode – endoscopic cyclophotocoagulation – glaucoma – laser – transscleral
Acta Ophthalmol. 2015: 93: 395–401 ª 2014 Acta Ophthalmologica Scandinavica Foundation. Published by John Wiley & Sons Ltd
doi: 10.1111/aos.12529
Introduction Cyclophotocoagulation was first introduced in the early 1970s as a last-line surgery to lower intraocular pressure (IOP). Unlike standard glaucoma surgery such as trabeculectomy or aqueous drainage devices, cyclophotocoagulation aims to reduce the IOP by reducing aqueous production. Early iterations of cyclophotocoagulation delivered through a contact or non-contact approach were limited to patients with end-stage glaucoma. This was due to the unpredictability and complications such as hypotony and phthisis (Francis et al. 2014). In 1992, the first results were reported on a novel technique of ciliary body photocoagulation delivered under direct visualization through endoscopy (Uram 1992). The aim of this paper is to review the published English literature to discuss the indications, results and
complications of endoscopic cyclophotocoagulation (ECP).
Mechanism of Action Cyclophotocoagulation uses focused laser to ablate the ciliary body processes, a technique refined by transscleral delivery with a contact probe. The most commonly used laser is a semiconductor diode laser emitting at 810 nm (Chen et al. 1999). The diode laser causes coagulative necrosis of the ciliary body epithelium (pigmented and non-pigmented) as well as the stroma (Assia et al. 1991). This leads to hyalinization of the scleral collagen, disruption of the ciliary body epithelium and ciliary process atrophy (Cavens et al. 2012). The atrophy of the ciliary process decreases the amount of aqueous inflow, and this is thought to be the most important explanation of the IOP
decrease seen after the procedure. Another IOP-lowering effect may be increased uveoscleral outflow through the areas of damaged tissue (Coleman et al. 1985; Bloom & Dharmaraj 2006). Like the trans-scleral procedure, the endoscopic system uses a diode laser that emits pulsed continuous energy (Lin 2002). A rabbit study showed that following either trans-scleral or endoscopic diode laser, there was almost no blood flow on fluorescein angiography through the treated ciliary processes (Lin et al. 2006). The effect was seen immediately after laser application with little change until 1 month later. At that point, only the endoscopic group displayed some areas of reperfusion. An exudative membrane extending to the pars plana was only seen following trans-scleral laser. Otherwise, similar histological effects were observed with both lasers, namely coagulative necrosis of the stroma and pigmented and nonpigmented ciliary body epithelial cells, leading to ciliary process atrophy.
Indications
Trans-scleral cyclophotocoagulation has traditionally been reserved for more advanced cases of glaucoma because of the higher risk of sightthreatening complications as compared with penetrating surgery (Iliev & Gerber 2007). ECP has been used to treat primary open-angle glaucoma (POAG), pigmentary and neovascular glaucoma (NVG), chronic angle closure glaucoma (CACG), postpenetrating keratoplasty (Murthy et al. 2009), iridocorneal syndrome (Clement et al. 2013), as well as congenital (Lima et al.
395
Acta Ophthalmologica 2015
2004), uveitic (Lima et al. 2004), anglerecession (Lima et al. 2004) and normal-tension glaucoma (Kahook et al. 2007a). Absolute contraindications have not been reported. Technique
The endoscopic diode laser unit manufactured by Endo Optiks (Little Silver, NJ, USA) has a 670-nm laser to provide the aiming beam, a 175 W xenon light source and an endoscope built into the diode laser probe (Jacobi & Dietlein 2000; Lin 2002). Similar to the trans-scleral diode laser, the laser is triggered by a foot pedal that fires the laser as long as the pedal is depressed, up to 9.99 s. The maximum power setting is 1.2 W (Carter et al. 2007). Preoperative considerations are similar to phacoemulsification, although retrobulbar anaesthesia is frequently employed (Chen et al. 1997; Francis et al. 2011). The probe can be inserted through a temporal incision made either at the limbus or at the pars plana 3.5-mm posterior to the limbus (Lima et al. 2004). With the pars plana approach, a vitrectomy is usually performed before inserting the probe through the sclerostomy, (Murthy et al. 2009) although cases have been reported without a vitrectomy (Raizada & Al Sabti 2009). With the limbal approach, a 2.5-mm clear-corneal incision can be made (Francis et al. 2014). If it is being performed in conjunction with phacoemulsification, ECP is performed after the intraocular lens is placed. The anterior chamber as well as the ciliary sulcus is further expanded with cohesive viscoelastic. The probe is inserted under microscopic view and advanced to the pupil. At this point, attention should be turned towards the camera monitor and the probe is
advanced towards the ciliary body until 6–8 processes fill the view (Francis et al. 2014). This correlates with a 2-mm separation between the probe tip and the ciliary process, which has been measured to provide the delivered laser energy as close as possible to the power displayed on the readout (Yu et al. 2008). A typical power setting is 500 mW for 0.5–2 s (Chen et al. 1997). The aiming beam is directed at the centre of a process, and the laser is fired along the entire length of the process until it whitens and tissue shrinkage is noted. Scleral depression can be done to ensure the entire length of the ciliary process is visualized and treated (Lima et al. 2004). The circumference of treatment has varied from 90 (Uram 1992) to 360 (Francis et al. 2014) degrees (see the results section for further details). With a single incision, it is possible to view and treat up to 300 degrees (Kahook et al. 2007a). Making a second incision up to 180 degrees away allows for 360 degrees of treatment. At the end of the case, the viscoelastic should be aspirated out and the wounds hydrated. Dexamethasone should be injected subconjunctivally (Lima et al. 2004). Postoperatively, a topical fluoroquinolone, prednisolone acetate 1% and non-steroidal anti-inflammatory can be given four times a day (Kahook et al. 2007a). The IOP decrease may not be expected immediately, especially with retained viscoelastic which was injected in the ciliary sulcus (Netland et al. 2007). A small case series of ECP performed with an AC maintainer and iris hooks in place of viscoelastic had a significantly lower IOP on the first postoperative day (Kahook et al. 2007b). The patient’s current glaucoma medications are often continued into
the postoperative visits until the IOPlowering effect is observed (Francis et al. 2011). Many studies did not report the IOP or number of medications on the first postoperative day. However, in one study, the IOP on postoperative day 1 (off glaucoma medications) was only reduced by an average of 14% from baseline (Yip et al. 2009).
Results ECP is frequently reported for use in one of two different subsets: mild POAG or advanced secondary glaucomas. Only a single study (n = 63, retrospective) stratified their results between POAG and secondary glaucomas. First, they separately analysed POAG versus any other type of glaucoma and found that the POAG group had a mean 22% decrease from a baseline of 21 mmHg, while other glaucomas had a 29% decrease from a baseline of 22 mmHg. They did not report whether the difference between the two groups was statistically significant. They also re-divided their cases into primary surgery versus cases with a history of failed glaucoma surgery prior to ECP. The surgically naive group had a mean 30% decrease from a baseline of 22 mmHg, while those with previous surgery had a 17% decrease from a baseline of 20 mmHg. Again, it was not noted whether the difference reached statistical significance. Based on the available data, we have calculated an overall average for POAG (Table 1) versus secondary glaucomas (Table 2). In the POAG studies, most of which were categorized as mild, the mean IOP decrease ranged from 3.9 mmHg (Yip et al. 2009) to 10.9 mmHg (Lima et al. 2010) or 18% (Yip et al. 2009) –47% (Lima et al.
Table 1. Review of published results for endoscopic cyclophotocoagulation in primary open-angle glaucoma.
First author
Study type
Gayton (Gayton et al. 1999)
Prospective, randomized Retrospective Retrospective Retrospective Retrospective Retrospective Retrospective
Kahook (Kahook et al. 2007b) Kahook (Kahook et al. 2007a) Yip (Yip et al. 2009) Lima (Lima et al. 2010) Lindfield (Lindfield et al. 2012) Clement (Clement et al. 2013)
396
# eyes in the ECP group 29 15 40 29 368 56 63
Mean baseline IOP in mmHg 24.8 22.7 (mean of all patients) 24 (mean of all patients) 21.8 23.1 21.5 21.1
Final mean decrease in IOP, mmHg (%) 8.8 (29%) 6.3 9.5 3.9 10.9 7.1 5
(28%) (40%) (18%) (47%) (33%) (24%)
Mean # decrease in medication 0.06 Not reported 1.3 0.8 1.1 +0.06 (increased) 1.2
Study length 24 months 1 month 6 months 24 months 24 months 24 months 12 months
Acta Ophthalmologica 2015
Table 2. Review of published results for endoscopic cyclophotocoagulation in secondary glaucomas.
First author
Study type
Uram (Uram 1992)
Retrospective
Chen (Chen et al. 1997) Lima (Lima et al. 2004) Carter (Carter et al. 2007) Lima (Lima et al. 2009) Murthy (Murthy et al. 2009) Francis (Francis et al. 2011)
Retrospective Prospective Retrospective Retrospective Prospective Prospective
2010), where the mean IOP decrease was 7 mmHg or 31%. In the advanced secondary glaucoma group, the IOP decreased from 7 mmHg (Francis et al. 2011) to 28 mmHg (Uram 1992) or 26% (Francis et al. 2011) –68% (Lima et al. 2009), yielding a mean 18 mmHg or 50% IOP decrease. The first reported results of ECP came in 1992 after use in 10 patients with neovascular glaucoma who were followed for 6–11 months after 90–180 degrees of treatment (Uram 1992). The mean IOP fell 65% from a baseline of 44 mmHg. Six of 10 cases maintained an IOP < 21 off of all medications. The maximum IOP decrease was seen after 6 weeks. A retrospective review of 68 cases showed that the IOP was lowered by 34% from a baseline of 28 mmHg with an average follow-up period of 13 months (Chen et al. 1997). The number of medications decreased from 3 to 2. While only 74% of cases had a 20% IOP decrease from baseline, 94% of cases had an IOP ≤21 at 1 year and 82% did so at 2 years. A large prospective series of 45 cases, where the most common diagnosis was neovascular glaucoma, showed a 61% decrease in IOP from a baseline of 33 mmHg on 1.4 less medications after 21 months (Murthy et al. 2009). The two largest studies were done by the same author. The first reviewed 368 cases of combined phacoemulsification and ECP for POAG (Lima et al. 2010). The IOP decreased by 47% from a baseline of 23 mmHg after both 1 and 2 years, on 1.1 fewer medications. The most common complication was an IOP spike, which they observed in 14% of cases (although they measured the IOP only 3 hr after surgery). At 2 years, an IOP between 5–21 mmHg was achieved with medications in 91% of patients and without any medications in 56% of
# eyes in the ECP group
Mean baseline IOP in mmHg
Final mean decrease in IOP, mmHg (%)
Mean # decrease in medication
10
43.6
28.3 (65%)
68 34 34 539 45 25
27.7 41.6 32.6 38.1 32.6 24
10.7 27.5 9.7 26 19.8 7
Only specified 66% stopped acetazolamide 1 1 0 2 1.4 1.2
(34%) (66%) (30%) (68%) (61%) (26%)
cases. Persistent vision loss occurred in only 1%, from CME. The largest published study was a retrospective review of 539 patients who were followed for an average of 7.4 years (Lima et al. 2009). The laser was applied for 210 degrees and 50% of the patients had either POAG or CACG, with the third most common diagnosis being neovascular glaucoma (17%). The mean IOP decreased 68% from a mean baseline of 38 mmHg on 2 fewer medications after 5 years. The IOP was between 6– 21 mmHg in 93% of cases after 1 year and in 79% after 5 years. The average number of medications at 5 years was 1.9, and only 22% of cases were off medications. The vision was stable or improved in 95%. ECP has been used following failed aqueous shunts. A prospective study (n = 25) found that ECP lowered the IOP by 26% from a baseline of 24 mmHg 2 years after the ECP (Francis et al. 2011). The number of medications went from 3.2 at baseline, to 1.5 at 1 year, but then increased to 2 at 2 years. Defining success as an IOP ≤21, along with either a decrease from baseline IOP by 3 mmHg or a decrease in the number of medications, the success rate at 2 years was 88%. ECP was performed for paediatric aphakic glaucoma in a group of 34 eyes with an average age of 4.2 years (Carter et al. 2007). The IOP decreased by 30% from a baseline of 32.6 mmHg after 44 months, with no change in number of medications. Defining success as IOP
