Downloaded from http://bjo.bmj.com/ on June 18, 2015 - Published by group.bmj.com
PostScript
High-frequency ultrasoundguided transscleral diode laser cyclophotocoagulation INTRODUCTION Coagulation of the ciliary body via transscleral diode laser cyclophotocoagulation (cyclodiode) of the ciliary body is a therapeutic option for numerous types of glaucoma. It is commonly used in patients with refractory glaucoma for a temporising effect prior to drainage procedures, as an adjunct to surgery, in patients who are precluded from undergoing general anaesthesia, or in individuals who have no visual potential and need pain relief.1 Typically, the probe is applied to a point
corresponding to the pars plicata of the ciliary body. This has been historically identified as 1–2 mm behind the limbus or via transillumination. Recognition of the location of the ciliary body is paramount to correctly performing this procedure. Accurate identification is of special concern in paediatric glaucoma patients, as the actual position of the ciliary body may vary by axial length, quadrant of the eye and between individuals.2 Identification of the ciliary body in the paediatric glaucoma population also poses a unique challenge given possible anterior segment dysgenesis. Additionally, aphakic paediatric glaucoma patients may have an increased risk of significant postoperative complications, such as retinal detachment.3
Figure 1 (A) Ultrasound biomicroscopy screenshot showing the location of the thin scleral indenter casting an acoustic shadow (white arrow) over the anterior ciliary body. This shows that the scleral indentation mark is appropriate to use for placement of the laser probe. (B) In contrast, this screenshot demonstrates that the location of the acoustic shadow cast by the scleral indenter is far more posterior than appropriate (white arrow) in a case of aphakic glaucoma. In this case, the positioning of the indenter had been determined via conventional transillumination. The indentation mark left by the indenter would be in an inaccurate location to deliver laser energy and could lead to retinal detachment. 992
Br J Ophthalmol July 2014 Vol 98 No 7
Downloaded from http://bjo.bmj.com/ on June 18, 2015 - Published by group.bmj.com
PostScript body demonstrates effective laser treatment (figure 2). ‘Pops’ are avoided but if heard demonstrate a destructive process. If the treated area is re-examined months later, atrophy of the ciliary body can be seen.
DISCUSSION This technique allows for high-resolution images of anterior segment anatomy, and for visualisation of the exact location and extent of the ciliary body. These images serve to confirm location prior to and following cyclodiode laser. Although this technique requires additional time, it has great potential to increase predictability, accuracy and safety of glaucoma surgery. Whether this technique increases efficacy of transcleral diode laser remains to be seen and will be the subject of a prospective study. However, it potentially may reduce the risk of inadvertent retinal detachments as previously described in transcleral diode laser (1) and avoids the need of intraocular surgery when using endocyclophotocoagulation with the inherent risk of endophthalmitis. Amanda L Way,1 Ken K Nischal2 1
Department of Ophthalmology, UPMC Eye Center, Pittsburgh, Pennsylvania, USA Department of Pediatric Ophthalmology, Strabismus and Adult Motility, Children’s Hospital of Pittsburgh of UPMC, Pittsburgh, Pennsylvania, USA
2
Figure 2 (A) Ultrasound biomicroscopy screenshot showing the ciliary body prior to delivery of laser energy. (B) Immediately after delivery of the laser energy during which no ‘pop’ was heard, there is a swelling of the ciliary body and evidence of hypo-echogenicity within the ciliary body consistent with a bubble of gas. Continued delivery of laser energy would lead to a ‘pop’.
One particular modality in which iridocorneal anatomy can be visualised is through high frequency ultrasound biomicroscopy (UBM) (Paradigm Medical Industries, Salt Lake City, Utah, USA). UBM is a non-invasive tool that provides high-resolution in vivo imaging of the anterior segment. Various high frequency ultrasound transducers between 50 and 100 MHz are included into a clinical B-scan device.4 This imaging modality has been used to study various aspects of anterior segment anatomy and pathophysiology.5 We present a novel technique using UBM to identify the ciliary body prior to cyclophotocoagulation.
SURGICAL TECHNIQUE Using transillumination, the putative ciliary body is marked with a scleral indenter. With this in place, the ultrasound probe is placed over the indenter with a coupling agent between the two Br J Ophthalmol July 2014 Vol 98 No 7
instruments and ultrasound is performed. The indenter casts an acoustic shadow. If the putative ciliary body found on transillumination is in fact anatomically correct, a shadow is cast over the anterior ciliary body (figure 1A). Identification through transillumination does not always correspond with the actual location of the ciliary body such as in cases of paediatric glaucoma with buphthalmos or aphakic glaucoma (figure 1B). In these situations, the scleral indenter is readjusted to a more appropriate position and ultrasound is performed until the shadow is cast in the correct area. The scleral indent left by the scleral indenter is then used to position the heel of the contact laser probe. Photocoagulation is then performed using approximately 6–8 pulses per quadrant of up to 2000 milliwatts for 2 s in the inferior 180°. Following cyclodiode laser, the ciliary body is again visualised with the UBM. A bubble within the ciliary
Correspondence to Dr Ken K Nischal, Department of Pediatric Ophthalmology, Strabismus and Adult Motility, Children’s Hospital of Pittsburgh of UPMC, 4401 Penn Ave. CHP Faculty Pavilion, Suite 5000, Pittsburgh, PA 15224, USA; [email protected] Contributors Both authors contributed equally to the manuscript. Competing interests None. Provenance and peer review Not commissioned; internally peer reviewed.
To cite Way AL, Nischal KK. Br J Ophthalmol 2014;98:992–994. Received 26 February 2014 Accepted 1 March 2014 Published Online First 1 April 2014 Br J Ophthalmol 2014;98:992–994. doi:10.1136/bjophthalmol-2014-305163
REFERENCES 1
2
Kirwan JF, Shah P, Khaw PT. Diode laser cyclophotocoagulation: role in the management of refractory pediatric glaucomas. Ophthalmology 2002;109:316–23. Agrawal P, Martin KR. Ciliary body position variability in glaucoma patients assessed by scleral transillumination. Eye 2008;22:1499–503.
993
Downloaded from http://bjo.bmj.com/ on June 18, 2015 - Published by group.bmj.com
PostScript 3
4
5
994
Autrata R, Rehurek J. Long-term results of transscleral cyclophotocoagulation in refractory pediatric glaucoma patients. Ophthalmologica 2003;217:393–400. Pavlin CJ, Harasiewicz K, Sherar MD, et al. Clinical use of ultrasound biomicroscopy. Ophthalmology 1991;98:287–95. Ishikawa H, Schuman JS. Anterior segment imaging: ultrasound biomicroscopy. Ophth Clin North Amer 2004;17:7–20.
Br J Ophthalmol July 2014 Vol 98 No 7
Downloaded from http://bjo.bmj.com/ on June 18, 2015 - Published by group.bmj.com
High-frequency ultrasound-guided transscleral diode laser cyclophotocoagulation Amanda L Way and Ken K Nischal Br J Ophthalmol 2014 98: 992-994 originally published online April 1, 2014
doi: 10.1136/bjophthalmol-2014-305163 Updated information and services can be found at: http://bjo.bmj.com/content/98/7/992
These include:
References Email alerting service
This article cites 5 articles, 0 of which you can access for free at: http://bjo.bmj.com/content/98/7/992#BIBL Receive free email alerts when new articles cite this article. Sign up in the box at the top right corner of the online article.
Notes
To request permissions go to: http://group.bmj.com/group/rights-licensing/permissions To order reprints go to: http://journals.bmj.com/cgi/reprintform To subscribe to BMJ go to: http://group.bmj.com/subscribe/
PostScript
High-frequency ultrasoundguided transscleral diode laser cyclophotocoagulation INTRODUCTION Coagulation of the ciliary body via transscleral diode laser cyclophotocoagulation (cyclodiode) of the ciliary body is a therapeutic option for numerous types of glaucoma. It is commonly used in patients with refractory glaucoma for a temporising effect prior to drainage procedures, as an adjunct to surgery, in patients who are precluded from undergoing general anaesthesia, or in individuals who have no visual potential and need pain relief.1 Typically, the probe is applied to a point
corresponding to the pars plicata of the ciliary body. This has been historically identified as 1–2 mm behind the limbus or via transillumination. Recognition of the location of the ciliary body is paramount to correctly performing this procedure. Accurate identification is of special concern in paediatric glaucoma patients, as the actual position of the ciliary body may vary by axial length, quadrant of the eye and between individuals.2 Identification of the ciliary body in the paediatric glaucoma population also poses a unique challenge given possible anterior segment dysgenesis. Additionally, aphakic paediatric glaucoma patients may have an increased risk of significant postoperative complications, such as retinal detachment.3
Figure 1 (A) Ultrasound biomicroscopy screenshot showing the location of the thin scleral indenter casting an acoustic shadow (white arrow) over the anterior ciliary body. This shows that the scleral indentation mark is appropriate to use for placement of the laser probe. (B) In contrast, this screenshot demonstrates that the location of the acoustic shadow cast by the scleral indenter is far more posterior than appropriate (white arrow) in a case of aphakic glaucoma. In this case, the positioning of the indenter had been determined via conventional transillumination. The indentation mark left by the indenter would be in an inaccurate location to deliver laser energy and could lead to retinal detachment. 992
Br J Ophthalmol July 2014 Vol 98 No 7
Downloaded from http://bjo.bmj.com/ on June 18, 2015 - Published by group.bmj.com
PostScript body demonstrates effective laser treatment (figure 2). ‘Pops’ are avoided but if heard demonstrate a destructive process. If the treated area is re-examined months later, atrophy of the ciliary body can be seen.
DISCUSSION This technique allows for high-resolution images of anterior segment anatomy, and for visualisation of the exact location and extent of the ciliary body. These images serve to confirm location prior to and following cyclodiode laser. Although this technique requires additional time, it has great potential to increase predictability, accuracy and safety of glaucoma surgery. Whether this technique increases efficacy of transcleral diode laser remains to be seen and will be the subject of a prospective study. However, it potentially may reduce the risk of inadvertent retinal detachments as previously described in transcleral diode laser (1) and avoids the need of intraocular surgery when using endocyclophotocoagulation with the inherent risk of endophthalmitis. Amanda L Way,1 Ken K Nischal2 1
Department of Ophthalmology, UPMC Eye Center, Pittsburgh, Pennsylvania, USA Department of Pediatric Ophthalmology, Strabismus and Adult Motility, Children’s Hospital of Pittsburgh of UPMC, Pittsburgh, Pennsylvania, USA
2
Figure 2 (A) Ultrasound biomicroscopy screenshot showing the ciliary body prior to delivery of laser energy. (B) Immediately after delivery of the laser energy during which no ‘pop’ was heard, there is a swelling of the ciliary body and evidence of hypo-echogenicity within the ciliary body consistent with a bubble of gas. Continued delivery of laser energy would lead to a ‘pop’.
One particular modality in which iridocorneal anatomy can be visualised is through high frequency ultrasound biomicroscopy (UBM) (Paradigm Medical Industries, Salt Lake City, Utah, USA). UBM is a non-invasive tool that provides high-resolution in vivo imaging of the anterior segment. Various high frequency ultrasound transducers between 50 and 100 MHz are included into a clinical B-scan device.4 This imaging modality has been used to study various aspects of anterior segment anatomy and pathophysiology.5 We present a novel technique using UBM to identify the ciliary body prior to cyclophotocoagulation.
SURGICAL TECHNIQUE Using transillumination, the putative ciliary body is marked with a scleral indenter. With this in place, the ultrasound probe is placed over the indenter with a coupling agent between the two Br J Ophthalmol July 2014 Vol 98 No 7
instruments and ultrasound is performed. The indenter casts an acoustic shadow. If the putative ciliary body found on transillumination is in fact anatomically correct, a shadow is cast over the anterior ciliary body (figure 1A). Identification through transillumination does not always correspond with the actual location of the ciliary body such as in cases of paediatric glaucoma with buphthalmos or aphakic glaucoma (figure 1B). In these situations, the scleral indenter is readjusted to a more appropriate position and ultrasound is performed until the shadow is cast in the correct area. The scleral indent left by the scleral indenter is then used to position the heel of the contact laser probe. Photocoagulation is then performed using approximately 6–8 pulses per quadrant of up to 2000 milliwatts for 2 s in the inferior 180°. Following cyclodiode laser, the ciliary body is again visualised with the UBM. A bubble within the ciliary
Correspondence to Dr Ken K Nischal, Department of Pediatric Ophthalmology, Strabismus and Adult Motility, Children’s Hospital of Pittsburgh of UPMC, 4401 Penn Ave. CHP Faculty Pavilion, Suite 5000, Pittsburgh, PA 15224, USA; [email protected] Contributors Both authors contributed equally to the manuscript. Competing interests None. Provenance and peer review Not commissioned; internally peer reviewed.
To cite Way AL, Nischal KK. Br J Ophthalmol 2014;98:992–994. Received 26 February 2014 Accepted 1 March 2014 Published Online First 1 April 2014 Br J Ophthalmol 2014;98:992–994. doi:10.1136/bjophthalmol-2014-305163
REFERENCES 1
2
Kirwan JF, Shah P, Khaw PT. Diode laser cyclophotocoagulation: role in the management of refractory pediatric glaucomas. Ophthalmology 2002;109:316–23. Agrawal P, Martin KR. Ciliary body position variability in glaucoma patients assessed by scleral transillumination. Eye 2008;22:1499–503.
993
Downloaded from http://bjo.bmj.com/ on June 18, 2015 - Published by group.bmj.com
PostScript 3
4
5
994
Autrata R, Rehurek J. Long-term results of transscleral cyclophotocoagulation in refractory pediatric glaucoma patients. Ophthalmologica 2003;217:393–400. Pavlin CJ, Harasiewicz K, Sherar MD, et al. Clinical use of ultrasound biomicroscopy. Ophthalmology 1991;98:287–95. Ishikawa H, Schuman JS. Anterior segment imaging: ultrasound biomicroscopy. Ophth Clin North Amer 2004;17:7–20.
Br J Ophthalmol July 2014 Vol 98 No 7
Downloaded from http://bjo.bmj.com/ on June 18, 2015 - Published by group.bmj.com
High-frequency ultrasound-guided transscleral diode laser cyclophotocoagulation Amanda L Way and Ken K Nischal Br J Ophthalmol 2014 98: 992-994 originally published online April 1, 2014
doi: 10.1136/bjophthalmol-2014-305163 Updated information and services can be found at: http://bjo.bmj.com/content/98/7/992
These include:
References Email alerting service
This article cites 5 articles, 0 of which you can access for free at: http://bjo.bmj.com/content/98/7/992#BIBL Receive free email alerts when new articles cite this article. Sign up in the box at the top right corner of the online article.
Notes
To request permissions go to: http://group.bmj.com/group/rights-licensing/permissions To order reprints go to: http://journals.bmj.com/cgi/reprintform To subscribe to BMJ go to: http://group.bmj.com/subscribe/
