Volume 38, Issue 1 , Pages 5-7, January 2012
Black-on-clear piggyback technique for a black occlusive intraocular device in intractable diplopia
Article Outline
- Abstract
- Surgical technique
- Discussion
- Supplementary data
- References
- Other Cited Material
- Biography
- Copyright
Black occlusive intraocular devices have been used successfully for intractable binocular diplopia. We describe a novel technique of implanting both a black occlusive device and a clear poly(methyl methacrylate) intraocular lens (IOL) in the capsular bag during phacoemulsification surgery. If the need should arise at a later date, this approach will allow safer and easier explantation of the black occlusive device, avoiding the need for IOL exchange.
Financial Disclosure
No author has a financial or proprietary interest in any material or method mentioned.
Established treatment modalities for diplopia from paralytic strabismus include wearing an occlusive eye patch, opaque spectacle lens and occlusive contact lenses, upper lid lowering, or tarsorrhaphy. More recently, black occlusive intraocular devices have also been used successfully for intractable binocular diplopia.1, 2 The technique shows a good success rate with high patient satisfaction.3 In a questionnaire survey, 72% of ophthalmologists in the United Kingdom responded they would consider using intraocular occlusive devices in cases of intractable diplopia.4
In the event of sight loss in the nonoccluded eye, an intraocular lens (IOL) exchange would be required for the patient’s visual rehabilitation. This can be technically challenging once capsular healing has occurred, reducing the likelihood of leaving the eye with a new in-the-bag IOL. We present our experience using the combination of an opaque intraocular occlusive device and a clear poly(methyl methacrylate) (PMMA) IOL placed in the capsular bag at the time of surgery to avert the need for later IOL exchange should the fellow eye meet visual failure.
Surgical technique
Scotopic pupillometry is performed preoperatively to ensure the pupil diameter is smaller than the optic diameter of the selected IOL. The initial part of the procedure is the same as a standard phacoemulsification procedure, using a lens removal technique in accord with the surgeon’s preference. The use of a posterior scleral tunnel wound avoids the need for suture placement. After the remaining soft lens material is carefully aspirated and the capsule cleaned, a suitably powered PMMA clear IOL (Morcher 65S) is placed in the capsular bag (Figure 1, A). This is followed by insertion of a black PMMA intraocular occlusive device (Morcher 85F; 6.0 mm optic diameter, 12.0 mm overall diameter, 10-degree haptic angulation) in the capsular bag as a piggyback device in front of the IOL (Figure 1, B). The occlusive device and the IOL have the same design except the occlusive device is made of black PMMA. The haptics of both devices can be dialed so they are aligned (Figure 1, C), and once the surgeon is certain they are safely and securely in the bag, the ophthalmic viscosurgical device can be removed, including that between the implants, and the procedure completed normally.
Figure 1
Black-on-clear polypseudophakia lens extraction with dual PMMA implants (1 opaque and 1 clear) placed in the bag. A: Phacoemulsification is performed as per routine practice, preferably through a scleral tunnel. After irrigation/aspiration, a clear PMMA IOL is inserted in the capsular bag. B: An opaque PMMA device is also placed in the capsular bag on top of the clear IOL. Note the size of the opaque device and that a large incision is necessary for placement. C: The haptics are placed parallel to one another with the implants sitting on top of each other. D: The opaque device viewed with an undilated pupil with good cosmetic effect.
Case Report
This technique was used in a 28-year-old man with Asperger syndrome (an autism spectrum disorder characterized by significant difficulties in social interaction along with restricted and repetitive patterns of behavior and interests), who had been under the care of the Hospital Eye Service for hypermetropia and a left convergent squint since he was 1 year of age. When the patient was 13 years old, strabismus surgery was performed with a good cosmetic and orthoptic outcome; however, the patient would often attempt to find and maintain the position of gaze that would lead him to experience double vision, with subsequent difficulty suppressing the second image. He disliked wearing glasses with the lens blackened and developed a corneal ulcer when wearing an occlusive contact lens.
The examination was as follows: Corrected distance visual acuity was 6/6 in the right eye and 6/12 in the left eye. Orthoptic assessment revealed a slight left exotropia for near and distance, and the orthoptic team was unable to join the diplopia or find a suppression area. It was decided to proceed with clear lens extraction in the patient’s left eye and insertion of an opaque intraocular occlusive device and a clear IOL (“black on clear”) in the capsular bag.
The technique was performed successfully (Video, available at http://jcrsjournal.org), and 6 months postoperatively, the patient remained symptom free and was happier cosmetically as he no longer required an occlusive spectacle lens (Figure 1, D). No complications have been observed during the follow-up period.
Discussion
The use of devices with an identical design allows the long-term stable alignment of the 2 piggyback implants in the capsular bag.5 A surgical option to this dual in-the-bag technique is to place the black occlusive device in the ciliary sulcus. However, apart from the reduced stability of a sulcus-fixated IOL, other complications such as iris capture, pupillary block glaucoma,6 and pigment dispersion syndrome7 can occur, making the dual in-the-bag technique a safer option. Caution should be exercised in patients who are visually immature, and we would not recommend an intraocular occlusive device in these patients, although it is unusual for young children to complain of double vision.
The choice of material is important in piggyback implants placed in the capsular bag. A visually significant interlenticular opacity can occur around a central contact zone between 2 foldable implants. Within the contact zone, optical power is lost secondary to mutual flattening. The interlenticular opacity comprises both Elschnig pearl-type material, which consists of proliferating/retained lens epithelial cells (LECs) in the interlenticular space, and amorphous membrane-type material, which consists of extracellular matrix deposits similar to LECs in appearance.8 These accumulations usually occur 1 to 2 years after primary in-the-bag implantation of foldable piggyback IOLs.
We would not recommend placing a rigid black PMMA device anterior to a foldable clear IOL. The central portion of the foldable IOL may be irreversibly dented (made concave) to conform to the posterior curvature of the black PMMA device in front and they may fuse together. Even if they do not fuse, the interlenticular opacity thus formed may become permanently adherent to the anterior surface of the posterior foldable clear IOL.
Poly(methyl methacrylate) is the desired material in a dual in-the-bag piggyback IOL system to eliminate the risk for interlenticular opacity. An interlenticular opacity has been shown to be significantly higher in acrylic IOLs than in PMMA IOLs, with an incidence of 43% and 22%, respectively.A
One concern in using a black occlusive device is the inability to visualize the fundus. It has recently been shown that most black occlusive devices demonstrate high levels of transmission of near infrared light, allowing imaging of the retina and reproduction of fine retinal features through all clinical scanning laser ophthalmoscopy or optical coherence tomography (OCT) imaging systems.9, 10 We were able to image the fovea using an OCT system, although due to the patient’s difficulties with fixation and concentration, the image quality was moderate.
If it is necessary to remove the black opaque device, we recommend that the surgeon first attempt to dial it out of the capsular bag and then remove it through a corneal limbal wound. Alternatively, the haptics can be amputated and left in situ and only the central disk of the device removed.
We recommend using dual PMMA implants placed in the bag as they have good long-term stability and minimal complications of interlenticular opacity.11 We have found that the haptics align naturally with minimal tilt or decentration, and they sit close together in apposition, producing minimal shift in axial position. Although we have not had to remove a piggyback PMMA device, we postulate that the IOL would remain centered in the capsular bag, although it may move slightly forward once the anterior opaque device has been removed. The shift in effective lens position is unlikely to be of clinical significance, especially in relation to anisometropia as the fellow eye will have little or no vision.
The above piggyback system, which we call black on clear, is an innovative approach for patients suffering from intractable diplopia whose symptoms cannot be controlled adequately with occlusive spectacles or contact lenses. By using a black occlusive device anterior to a clear IOL in the bag, it allows safe removal of the black occlusive device should the need arise, averting the need for IOL exchange. We recommend long-term follow-up of patients in whom this technique has been used.
Supplementary data
Video. Black-on-clear polypseudophakia lens extraction with dual PMMA implants (1 opaque and 1 clear) placed in the bag. A bowl-and-snail technique is used during phacoemulsification as the nucleus was soft. After irrigation/aspiration, a clear PMMA IOL was inserted into the capsular bag. Following this, an opaque device was also placed in the capsular bag with its haptics parallel to the clear IOL underneath.
References
- . Phacoemulsification and opaque intraocular lens implantation for the treatment of intractable diplopia. Ophthalmic Surg Lasers. 2000;31:429–431
- . Black occlusive IOLs. [letter] Ophthalmology. 2007;114:2365–2365.e2
- . Opaque intraocular lens for intractable diplopia: experience and patients’ expectations and satisfaction. Br J Ophthalmol. 2008;92:912–915
- . Opaque intraocular lens for intractable diplopia—UK survey. Strabismus. 2009;17:167–170
- . Primary polypseudophakia for cataract surgery in hypermetropic eyes: refractive results and long term stability of the implants within the capsular bag. Br J Ophthalmol. 2001;85:1198–1202Available at: http://www.ncbi.nlm.nih.gov/pmc/articles/PMC1723740/pdf/v085p01198.pdfAccessed October 4, 2011
- . Pupillary block glaucoma associated with secondary piggyback intraocular lens. J Cataract Refract Surg. 2007;33:1813–1814
- . Secondary pigmentary glaucoma associated with piggyback intraocular lens implantation. J Cataract Refract Surg. 2004;30:2219–2222
- . Interlenticular opacification in piggyback AcrySof intraocular lenses: explanation technique and laboratory investigations. Br J Ophthalmol. 2001;85:830–836Available at: http://www.ncbi.nlm.nih.gov/pmc/articles/PMC1724053/pdf/v085p00830.pdfAccessed October 4, 2011
- . Imaging the macular through a black occlusive intraocular lens. Arch Ophthalmol. 2010;128:1374–1376
- . Occlusive IOLs for intractable diplopia demonstrate a novel near-infrared window of transmission for SLO/OCT imaging and clinical assessment. Invest Ophthalmol Vis Sci. 2011;52:3737–3743
- . Polypseudophakia for cataract surgery: 10-year follow-up on safety and stability of two poly-methyl-methacrylate (PMMA) intraocular lenses within the capsular bag. Eye. 2011;25:1090–1093Available at: http://www.nature.com/eye/journal/v25/n8/pdf/eye2011107a.pdfAccessed October 4, 2011
Other Cited Material
- Gayton JL, Apple DJ, “Refractive Stability and Long Term Interlenticular Membrane Formation of Piggyback Intraocular Implants,” presented at the annual meeting of the American Academy of Ophthalmology, Orlando, Florida, USA, October 1999
First author:
Stephen D. Byard, FRCOphth
Sussex Eye Hospital, Brighton, United Kingdom
PII: S0886-3350(11)01576-8
doi:10.1016/j.jcrs.2011.10.020
© 2012 ASCRS and ESCRS. Published by Elsevier Inc. All rights reserved.
Volume 38, Issue 1 , Pages 5-7, January 2012
