Simulation of neodymium:YAG posterior capsulotomy for ophthalmologists in training Elad Moisseiev, MD, Adi Michaeli, MD We describe a new method for training ophthalmologists to perform a neodymium:YAG (Nd:YAG) posterior capsulotomy. Our model consists of an artificial anterior chamber that can be adjusted to fit any laser instrument and houses an intraocular lens (IOL). The posterior surface of the IOL is coated with a crust simulating posterior capsule opacification (PCO). This model PCO reacts similarly to real PCO when the Nd:YAG laser is applied to it. It creates conditions simulating near-real posterior capsulotomy and has been used successfully to train 3 novice residents who had not performed the procedure. The model is simple, reusable, and inexpensive. We believe it may be a valuable tool in training ophthalmologists to perform an Nd:YAG posterior capsulotomy. Financial Disclosure: Neither author has a financial or proprietary interest in any material or method mentioned. J Cataract Refract Surg 2014; 40:175–178 Q 2014 ASCRS and ESCRS Posterior capsule opacification (PCO) is the most common long-term complication of cataract surgery. 1 Advances in surgical techniques and intraocular lens (IOL) materials and designs have reduced the rate of PCO formation, but it is still a significant problem. 2 For the past 2 decades, the standard treatment of PCO has been neodymium:YAG (Nd:YAG) laser capsulotomy. 3 This procedure usually achieves a rapid improvement in visual acuity and glare. 4,5 Although it is a fast and simple procedure, Nd:YAG laser capsulotomy can be associated with several com- plications, including transient elevation of intraocular pressure, cystoid macular edema, retinal detachment, corneal edema, iris hemorrhage, uveitis, IOL subluxa- tion, and direct damage to the IOL. 2,5 Posterior capsule opacification is commonly encountered in clinical practice and Nd:YAG laser capsulotomy is a procedure with which all ophthal- mologists are familiar. In teaching institutions, it is often performed by residents and may be one of the prerequisites for completing the residency program. We describe a method for simulating PCO and for performing Nd:YAG laser capsulotomy under semi- realistic conditions. TECHNIQUE This technique provides a simulation of PCO that can be used by ophthalmologists in training to perform Nd:YAG laser posterior capsulotomy. The model includes several components: an IOL with artificial PCO, a model of an anterior chamber that contains the IOL, and an adjustable mechanical device that enables the artificial anterior chamber to be mounted on the laser slitlamp. Simulation of Posterior Capsule Opacification Any IOL can be used in this model. For economic reasons, it is preferable to use IOLs that have passed their expiration dates. The IOL is placed on a gauze pad with the posterior surface up. A drop of water or saline is put on the posterior surface of the optic. Then, an artificial sweetener powder (composed of dextrose and sucralose) is poured over the optic. It dissolves and a white paste hardens over the posterior surface of the optic. Excess material is removed using a surgical blade, leaving the posterior surface of the optic coated by a layer simulating PCO (Figure 1). Submitted: June 12, 2013. Final revision submitted: July 26, 2013. Accepted: July 30, 2013. From the Department of Ophthalmology, Tel Aviv Medical Center, Israel; affiliated with the Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel. Corresponding author: Elad Moisseiev, MD, Department of Ophthalmology, Tel Aviv Medical Center, Weitzman 6 Street, Tel Aviv, 64239 Israel. E-mail: [email protected]. Q 2014 ASCRS and ESCRS Published by Elsevier Inc. 0886-3350/$ - see front matter 175 http://dx.doi.org/10.1016/j.jcrs.2013.12.007 TECHNIQUE
Transcript
TECHNIQUE
Simulation of neody
mium:YAG posteriorcapsulotomy for ophthalmologists in training
Elad Moisseiev, MD, Adi Michaeli, MD
SubmittFinal revAccepte
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by Elsev
We describe a new method for training ophthalmologists to perform a neodymium:YAG (Nd:YAG)posterior capsulotomy. Our model consists of an artificial anterior chamber that can be adjusted tofit any laser instrument and houses an intraocular lens (IOL). The posterior surface of the IOL iscoated with a crust simulating posterior capsule opacification (PCO). This model PCO reactssimilarly to real PCO when the Nd:YAG laser is applied to it. It creates conditions simulatingnear-real posterior capsulotomy and has been used successfully to train 3 novice residentswho had not performed the procedure. The model is simple, reusable, and inexpensive. We believeit may be a valuable tool in training ophthalmologists to perform an Nd:YAG posteriorcapsulotomy.
Financial Disclosure: Neither author has a financial or proprietary interest in any material ormethod mentioned.
Posterior capsule opacification (PCO) is the mostcommon long-term complication of cataract surgery.1
Advances in surgical techniques and intraocular lens(IOL) materials and designs have reduced the rate ofPCO formation, but it is still a significant problem.2
For the past 2 decades, the standard treatment ofPCO has been neodymium:YAG (Nd:YAG) lasercapsulotomy.3 This procedure usually achieves arapid improvement in visual acuity and glare.4,5
Although it is a fast and simple procedure, Nd:YAGlaser capsulotomy can be associated with several com-plications, including transient elevation of intraocularpressure, cystoid macular edema, retinal detachment,corneal edema, iris hemorrhage, uveitis, IOL subluxa-tion, and direct damage to the IOL.2,5
Posterior capsule opacification is commonlyencountered in clinical practice and Nd:YAG lasercapsulotomy is a procedure with which all ophthal-mologists are familiar. In teaching institutions, it is
e 12, 2013.ubmitted: July 26, 2013.30, 2013.
rtment of Ophthalmology, Tel Aviv Medical Center,d with the Sackler Faculty of Medicine, Tel AvivAviv, Israel.
author: Elad Moisseiev, MD, Department of, Tel Aviv Medical Center, Weitzman 6 Street, Telrael. E-mail: [email protected].
d ESCRS
ier Inc.
often performed by residents and may be one of theprerequisites for completing the residency program.We describe a method for simulating PCO and forperforming Nd:YAG laser capsulotomy under semi-realistic conditions.
TECHNIQUE
This technique provides a simulation of PCO that canbe used by ophthalmologists in training to performNd:YAG laser posterior capsulotomy. The modelincludes several components: an IOL with artificialPCO, a model of an anterior chamber that containsthe IOL, and an adjustable mechanical device thatenables the artificial anterior chamber to be mountedon the laser slitlamp.
Simulation of Posterior Capsule Opacification
Any IOL can be used in this model. For economicreasons, it is preferable to use IOLs that have passedtheir expiration dates. The IOL is placed on a gauzepad with the posterior surface up. A drop of wateror saline is put on the posterior surface of the optic.Then, an artificial sweetener powder (composed ofdextrose and sucralose) is poured over the optic. Itdissolves and a white paste hardens over the posteriorsurface of the optic. Excess material is removed using asurgical blade, leaving the posterior surface of theoptic coated by a layer simulating PCO (Figure 1).
0886-3350/$ - see front matter 175http://dx.doi.org/10.1016/j.jcrs.2013.12.007
Figure 1. Enlarged view of a rigid IOLwith simulated PCO adherentto the posterior surface.
176 TECHNIQUE: POSTERIOR CAPSULOTOMY SIMULATION
Simulation of an Anterior Chamber
The Phaco Practice Patient Replacement Eye(GuldenOphthalmics) is a plasticmodel of the anteriorchamber used for training ophthalmologists toperform a capsulorhexis. For our model, several mod-ifications were applied to create a simulated anteriorchamber that holds the IOL. The back of the replace-ment eye is sawed off, and the contents simulatingthe lens are removed. The anterior plastic cornea isalso cut away, leaving an empty plastic anteriorchamber. The IOL is then inserted into this anteriorchamber, with the haptics in the surrounding plastic
J CATARACT REFRACT SURG - V
groove. The IOL is inserted so the simulated PCO ison the posterior aspect (Figure 2).
Placing the Model
An adjustable mechanical arm that enables themodel to fit into any laser instrument was made(Figure 3). To set up the model, the arm is attachedto the headrest of the laser instrument and adjustedso the coated IOL is in focus.
Once the model is assembled, it includes an artificialanterior chamber that houses the IOL whose posteriorsurface has been coated by a layer simulating PCO.The mechanical arm can be adjusted to fit the modelinto any laser instrument. The Nd:YAG laser canthen be used to perform the procedure, simulating aposterior capsulotomy. The model creates conditionsthat simulate a near-real capsulotomy. Sequential lasershots can be made in any desired pattern to achieve aposterior opening in the simulated PCO membrane(Figures 4 and 5). The Nd:YAG laser can be used inthis model with or without a contact lens.
The simulated PCO is approximately 200 mm thickmeasured by anterior segment optical coherencetomography (Visante, Carl Zeiss Meditec AG). Theopening created in the IOL by the Nd:YAG laser hasclear boundaries (Figure 6).
Results
The model was used to train 3 first-year residentswho had not performed an Nd:YAG posterior capsu-lotomy. After a brief explanation of the procedureand familiarization with the Nd:YAG laser instrumentand the simulated PCO model, the residents practicedperforming a posterior capsulotomy. Within a singlesession, the residents could perform an adequate pos-terior capsulotomy with no damage to the IOL.
Figure 2. The IOLwith simulated PCO locatedinside the plastic anterior chamber. A: Frontalview. The plastic cornea has been removed. B:Rear view. The back has been sawed off, andthe contents simulating the lens have beenremoved.
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Figure 3. A mechanical arm is adjusted to situate the model in theappropriate location for performing the capsulotomy. A: Adjustableconnector that attaches to the headrest of the slitlamp and controlsthe vertical location of the model. B: Adjustable connector thatcontrols the horizontal location of the model. C: Wooden plate hold-ing the model eye.
177TECHNIQUE: POSTERIOR CAPSULOTOMY SIMULATION
DISCUSSION
We believe it is always preferable to have residentspractice their skills on models in controlled environ-ments and that guidance and evaluation of theresidents' performances are crucial for their training.In real life, training to perform an Nd:YAG posteriorcapsulotomy is suboptimal for several reasons. First,training opportunities are dependent on incomingpatients, and each patient may have a different degreeof PCO. Since patients may present at variable fre-quencies, it is difficult to establish a fixed learning curvefor residents. Second, a supervising expert is not alwaysavailable for the residents. Most important, even underexpert supervision, the laser procedure carries a risk forcomplications. The simulator we describe allows resi-dents to perform posterior capsulotomy of a standard-ized PCO as often and as many times as they desire.
Figure 4. Stages of performingNd:YAGposterior capsulotomy on an IOLwanterior chamber. B: Small opening in the simulated PCO made by a shothe opening. C and D: Progression of the capsulotomy after more laser sh
J CATARACT REFRACT SURG - V
Their performance can be evaluated by a seniorophthalmologist at his or her convenience and there isno risk for complications or patient discomfort. Anothersignificant advantage of this model is the low cost. TheIOLs can be reused, and the running cost is the cost ofonly the sugar sweetener.
Although Nd:YAG laser capsulotomy has beenroutinely performed during the past 2 decades, ourreview of the literature revealed only 1 model fortraining ophthalmologists in performing this proce-dure.6 This model described a simulation of PCOusing a cardboard or plastic sheet placed behind anIOL inside an artificial globe. The model is flawedsince the materials used to simulate PCO do not reactto the Nd:YAG laser the way real PCO reacts. Rela-tively high energy is required to achieve very smallopenings in the simulated PCO, and IOL damageoccurs with every laser application.
Our model allows ophthalmologists in training togain a realistic experience in performing capsulotomy.The simulated PCO is thicker than real PCO, whichranges between 46 mm and 115 mm.7 We acknowledgethat the simulated PCO does not resemble the lightposterior capsule opacity caused by fibrotic opacifica-tion, which is sometimes present in patients whorequire posterior capsulotomy. However, the simu-lated PCO is intended to be an instructional tool andit is advantageous that it is clearly visible and reactsto the application of laser shots in a manner verysimilar to that of real PCO. Neodymium:YAG laserdamage to the IOL in the form of pitting or crackingoccurs in 4% to 40% of cases.5 This unwanted compli-cation can also occur in this model, and training with itmay minimize the risk of it occurring in real patients.
In summary, using this model can improve the feed-back residents receive on their performance ofNd:YAG posterior capsulotomy, increase their experi-ence and confidence before applying their skills in areal patient's eye, and even shorten their learningcurve. In addition to the model's realistic nature, it issimple to fashion and understand, reusable, and inex-pensive. We believe this model may be a valuable tool
ith simulated PCO.A: Rigid IOLwith simulated PCO in the artificialt of the Nd:YAG laser. The laser aiming beam is visible adjacent toots have been applied. E: Completed posterior capsulotomy.
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Figure 5. A cross-pattern posterior capsulotomy, which differs fromthe round pattern created in Figure 4.
Figure 6. Anterior segment optical coherence tomography of a rigidIOL with simulated PCO before (A) and after (B) Nd:YAG lasercapsulotomy.
178 TECHNIQUE: POSTERIOR CAPSULOTOMY SIMULATION
for training residents, refreshing the skills of practicingophthalmologists, and experimenting with new lasertechnologies for the treatment of PCO.
WHAT WAS KNOWN
� Neodymium:YAG posterior capsulotomy is a commonlyperformed procedure that may be associated with poten-tial complications.
� Current training is suboptimal since ophthalmologists intraining have no way to train and practice this skill beforeoperating on real patients.
WHAT THIS PAPER ADDS
� A simple, reusable, and inexpensive model that simulatesPCO and allows realistic conditions for training ophthal-mologists in performing Nd:YAG posterior capsulotomyis described.
� The model was effective in training beginning residents toperform the procedure before they attempted to treat realpatients.
REFERENCES1. Findl O, BuehlW, Bauer P, Sycha T. Interventions for preventing
