Hyperguides

Ophthalmology / Cataract

Microphthalmos and Piggyback IOLs

Joel K. Shugar, MD, MSEE
Article


Introduction

Microphthalmos is a rare, potentially devastating condition occurring in 0.046% to 0.11% of patients in several large ophthalmic out-patient populations.1 Congenital microphthalmos can be either associated with coloboma or other developmental anomalies, or isolated or "pure." This tutorial describes pure microphthalmos.

Pure microphthalmos, or nanophthalmos, is a rare condition in which an eye is reduced in size, typically 15 mm to 21 mm, and is associated with high hypermetropia (5 D to 16 D). An abnormally high ratio of lens volume to eye volume is present. Patients with nanophthalmos have unusually large crystalline lenses. Microcornea can reduce the corneal diameter to 8 mm to 10 mm. The anterior chamber is shallow, with a narrow anterior chamber angle.

Nanophthalmic eyes are predisposed to angle-closure glaucoma, partially as a result of lens growth with age. Scleral collagen has been shown to be ultrastructurally abnormal, resulting in a thickened sclera. This thickened sclera can obstruct vortex veins, leading to choroidal congestion, uveal effusion, choroidal detachment, and serous retinal detachment.2 Spontaneous choroidal detachment can cause elevation and forward rotation of the ciliary body, leading to both angle-closure and malignant glaucoma in these eyes. Chorioretinal folds and crowded optic discs may also be present.

Clinical and genetic evaluations of 22 patients with nanophthalmos who were members of a family in which nanophthalmos was transmitted in an autosomal-dominant manner revealed high hyperopia (range, 7.25 D to 13 D; mean, 9.88 D) and short axial length (range, 17.55 mm to 19.28 mm; mean, 18.13 mm).3 Twelve affected family members had angle-closure glaucoma or occludable anterior-chamber angles. Linkage analysis of a genome scan demonstrated highly significant evidence that nanophthalmos in this family is a result of a defect in a previously unidentified locus (NNO1) on chromosome 11.

Sudden decompression of the globe during surgery can aggravate the degree of uveal effusion in patients with nanophthalmos. Until the 1990s, patients who underwent intraocular surgery had a high rate of serious complications and blindness, and medication and laser therapy were preferred for angle-closure glaucoma in patients with nanophthalmos.1 In 1990, Jin and Anderson advocated prophylactic posterior sclerectomies or sclerotomies in conjunction with cataract and/or glaucoma surgery 4 to prevent postoperative uveal effusion in a small case series. I have not found a prophylactic sclerectomy or sclerotomy necessary when cataract surgery is performed using the techniques described herein. I have had no cases of uveal effusion in more than 100 successive cases of cataract extraction in nanophthalmic eyes. Using modern techniques, lensectomy/posterior chamber IOL implantation is curative with regard to the narrow angle component of the disease and is the treatment of choice to normalize angle geometry.

Refractive Considerations

Performing A-scan biometry in eyes with nanophthalmos can be a challenge and should be performed by a highly experienced examiner. The gates must be set carefully because the anterior chamber is abnormally shallow and the phakic lens abnormally thick; alternately, the calculated axial length factor (CALF) method, developed by Jack Holliday, MD, can be used. In the CALF method, identical ultrasound velocities are set for all chambers of the eye and a "fudge" factor of 0.32 mm is added. This eliminates the dependency upon the measured location of anterior and posterior aspect of phakic lens by assuming phakic lens thickness.

Optical coherence biometry is an invaluable tool in measuring axial lengths in nanophthalmic eyes and should be used where available. The Holladay II formula was developed specifically for such eyes and considers corneal diameter, anterior chamber depth, and phakic lens thickness in addition to keratometry and axial length, because anterior and posterior segment sizes can vary independently. IOL power errors in nanophthalmic eyes most often leave residual hyperopia. If both eyes require cataract extraction, I typically perform surgery on a patient's nondominant eye first and target for mild myopia. If this refractive goal is achieved, patients will tolerate monovision well. Even if the outcome is less myopic than predicted, a residual hyperopic error is still prevented. The achieved refractive result in the nondominant eye can be used to more aggressively target emmetropia in the dominant eye without a high risk of residual hyperopia. Corneal topography is routinely performed preoperatively and is the primary tool to plan astigmatic reduction, which is routinely performed in combination with cataract extraction.

IOL Selection

The appropriate IOL choice for eyes with nanophthalmos is currently under debate and being researched. To achieve emmetropia, most nanophthalmic eyes require a total IOL power that is significantly higher than 34 D, which is the limit of currently available foldable IOLs. Johnny Gayton, MD, was the first clinician to use piggyback posterior chamber lenses5 followed by Jim Gills, MD.6 I applied the piggyback technique to foldable IOLs.7 Subsequently, high-power PMMA IOLs have become available in the United States, but such lenses require a large wound that may predispose a patient to intra- or postoperative complications. Piggyback implantation of foldable IOLs allows maximum intraoperative control during cataract surgery and has provided uniformly excellent short-term results in nanophthalmic eyes. My current approach involves implanting two plate-haptic silicone IOLs in a piggyback configuration. Powers are evenly divided between the IOLs to maximize the modulation transfer function of the IOL pair and the increased depth-of-focus observed postoperatively in many nanophthalmic eyes.8

Interpseudophakos/Interlenticular Opacification
Interpseudophakos/interlenticular opacification (IPO/ILO) has emerged as a late complication of piggyback implantation.9-12 IPO/ILO is characterized by ingrowth of lens epithelial cells (LECs) between the IOLs 1 to 3 years following piggyback implantation. Interpseudophakos Elschnig pearl ingrowth (IPO-E) is most common and is associated with a late hyperopic shift in both PMMA and acrylic lens pairs. A-type LEC ingrowth (IPO-A), clinically presenting with a fibrocellular appearance similar to anterior capsular opacification, has also been observed.13

IPO/ILO has been observed in eyes with piggybacked PMMA IOLs and documented in anecdotal reports of eyes with piggybacked silicone IOLs. However, IPO/ILO most commonly occurs in eyes implanted with piggybacked acrylic IOLs; if possible, alternate optic materials should be selected. The incidence of IPO/ILO appears to correlate directly with the biocompatibility of the optic material.14 For piggyback implantation, RMX-3 silicone material (AA4204VL, Staar Surgical) is preferred to more biocompatible materials such as acrylic.

Harry Grabow, MD, first reported piggyback bag/bag placement of plate-haptic silicone lenses, with the plates placed perpendicularly.15 After having explored almost every conceivable variant of piggyback implantation, including heterogeneous plate-haptic/loop, I am currently using Dr. Grabow's technique for eyes requiring more than 34 D total IOL power.16 There is approximately a 0.5-mm central "dimple" defining the contact zone between the IOLs, which I have found to be without clinical significance. A 6-mm capsulorrhexis diminishes the force compressing the optics together and the size of this dimple.

Lenses consisting of RMX-3 silicone material have the lowest index of refraction and are the thickest foldable IOLs, and therefore minimize the contact zone and maximize the distance between the peripheries of the optics (which both serve to decrease the incidence of IPO/ILO). Because the crystalline lens in eyes with nanophthalmos is larger than in normal eyes, there is sufficient room in the bag for two IOLs, even two IOLs made of RMX-3, maximizing the postoperative dimensions of the angle relative to bag/sulcus implantation.

Another significant factor in the incidence of IPO/ILO is the relationship between the capsulotomy margin and the IOL optics. IPO/ILO is most frequently observed in cases in which the anterior capsulotomy margin overlaps the anterior optic margin or comes in contact with the interface between the lenses. To avoid late IPO/ILO, two looped posterior chamber IOLs should not be placed together in the capsular bag in conjunction with an ordinary sized capsulorrhexis that overlaps the margin of an anterior IOL. I developed the large capsulorrhexis strategy for looped lens pairs, in which a 6.25-mm to 6.75-mm capsulorrhexis is created and both haptic pairs are placed together in the capsular bag. A relative haptic orientation between the IOLs should be chosen to maximize clearance of the anterior capsular remnant from the anterior optic and peripheral interface between the IOLs, but perpendicular alignment best supports the zonule, acting like a capsular tension ring. Creating a large capsulorrhexis that extends close to the anterior zonular insertion can be technically challenging in these small eyes. Initially, if a large capsulorrhexis cannot be created safely, an alternate strategy can be used. Johnny Gayton, MD, and Samuel Masket, MD, have suggested placing the anterior chamber IOL in the ciliary sulcus in an attempt to avoid late IPO/ILO. Kenneth Rosenthal, MD, suggested a variant of this strategy in which a 30-D AcrySof IOL (Alcon, Ft. Worth, Texas) is placed in the bag and the eye is allowed to heal for 6 months, at which time any remaining ametropia can be corrected with a secondary IOL in the sulcus.17 However, bag placement of both haptic pairs minimizes pigment dispersion and maximizes the postoperative anterior chamber depth and angle dimensions. Therefore, when a large capsulorrhexis cannot be created initially, David Chang, MD, has suggested enlarging the capsulorrhexis after IOL implantation to fixate both haptic pairs in the bag.18

The preoperative consultation should include thorough discussion of the potential complications unique to patients with nanophthalmic eyes, including late IPO/ILO. Also, a clinician should emphasize the need for periodic long-term postoperative follow-up. Attentive follow-up of polypseudophakic eyes is important. Early cases may be treated with a YAG laser with the laser defocus set at 0, by meticulously focusing on the interface at the proximal margin of the IPO/ILO ingrowth.19 Once a gas bubble is created, I attempt to continually work within the bubble as material is removed from the peripheral interface between the lenses. IPO/ILO that is present centrally is treated last, using the gas bubble generated by the YAG laser to separate the lens optics at the site of the next YAG shot to avoid pitting of the lenses. Attempted surgical aspiration of the LECs from acrylic lenses leaves a densely adherent acellular protein that is difficult to remove, often necessitating IOL exchange.20 Dense opacification between the central interfaces requires a late IOL exchange in an increasingly large number of investigators' cases.

Cataract Extraction in Nanophthalmic Eyes

Preoperative Regimen
Preoperative intraocular pressure (IOP) should be controlled medically, if possible, and miotics should be discontinued. A nonsteroidal anti-inflammatory drug (NSAID), such as Acular (ketorolac tromethamine ophthalmic solution, Allergan), and a fluoroquinolone antibiotic are prescribed four times a day for 3 days preoperatively. Before surgery, at the surgical facility, one or two pledgets saturated with a mixture of tropicamide 1%, neosynephrine 10%, Acular, and Ciloxan (ciprofloxacin HCl ophthalmic solution, Alcon) are instilled into a patient's inferior conjunctival cul-de-sac, followed by a single drop of neosynephrine 10% once cardiovascular monitoring has been initiated.

Anesthetic Modality
Needle anesthesia is not recommended in patients with nanophthalmos because of the risk of an increased orbital pressure and worsening vortex vein congestion. In most cases, I supplement topical anesthesia with intracameral "Shugarcaine," which is lidocaine 4% MPF mixed 1:3 with BSS Plus (balanced salt solution plus bicarbonate dextrose and glutathione, Alcon) to produce a buffered 1% lidocaine solution that is nontoxic to the corneal endothelium. This regimen affords total pain control but allows patients to cooperate during the procedure.21 In extreme cases or when treating uncooperative patients, I choose general anesthesia to maximize control during the procedure.

Surgical Approach
For surgery, I approach the eye temporally, which is helpful in accessing nanophthalmic eyes, which tend to be deep set and associated with prominent brows. First, I correct any astigmatism with arcuate keratotomy using a trifacet rectangular diamond blade at an 8-mm optical zone. Next, this blade is used to create a Langerman groove (3 mm in length and 500 µm to 600 µm in depth) at the temporal limbus. I use an angled, 15° blade to create a 0.75-mm beveled sideport incision 3 clock hours from the primary incision. When creating the sideport, care must be taken to avoid the iris and anterior capsule because the anterior chamber is typically extremely shallow. A dose of 0.5 cc of Shugarcaine is slowly instilled into the anterior chamber. After several seconds, I slowly fill the chamber with Viscoat (sodium chondroitin sulfate/sodium hyaluronate, Alcon). I am currently evaluating Healon 5 (sodium hyaluronate 2.3%, Pharmacia) for this application, as well. Next, I use a 2.5-mm Rhein 3D diamond blade to create a tunnel 300 µm in depth and 1.75 mm in length. Precise incision architecture is important in these cases to maximize endothelial clearance during surgery and maintain maximum control over ocular pressure.22-23

Prior to performing an anterior capsulotomy, I use the "soft shell" technique originated by Steve Arshinoff, MD, in which sodium hyaluronate 1% is instilled over the proximal iris and in the anterior capsule. Using dissimilar viscoelastic rheologies prevents iris prolapse during subsequent steps. The cohesive nature of the sodium hyaluronate allows egress from the anterior chamber as a mass without dragging iris along with it; if dispersive Viscoat were used alone, iris prolapse would be more likely as the viscoelastic flows out of the incision during creation of the capsulorhexis. Posterior synechiae are released with a Kuglen hook, cyclodialysis spatula, or viscoelastic cannula. For small pupils, the 3-point Beehler dilator (Moria, Doylestown, Pa) can be inserted through the unenlarged wound and used to stretch the pupil. However, such a maneuver can result in a floppy iris that is more prone to prolapse so cases must be assessed on an individual basis.

Nanophthalmic eyes often have weak or missing zonular fibers and have been associated with pseudoexfoliation syndrome. A capsulorrhexis must be performed with maximum delicacy, which can be achieved by beginning the capsulorrhexis with a cystitome and completing it with forceps. If zonular weakness or dialysis is present, a capsular tension ring should be placed following completion of the capsulorrhexis. Because piggybacked IOLs are required, the size of the capsulorrhexis depends on the chosen strategy to avoid IPO/ILO. Primary creation of a large capsulorrhexis in these eyes requires significant surgical experience and should not be attempted if a surgeon is not confident in his or her ability to meticulously complete this step. Alternately, either secondary enlargement of the capsulorrhexis after IOL placement or use of the bag/sulcus IOL strategy will allow initial creation of an ordinary size capsulorrhexis in concert with a strategy to prevent late IPO/ILO.

I perform hydrodissection subincisionally with a J-shaped cannula, passing a fluid wave every clock hour. Then, the nucleus is gently decompressed. Hydrodissection is continued nasally every clock hour by injecting Shugarcaine through a flat cannula. Twelve hydrodissection waves are used to maximize LEC and cortex removal. David Apple, MD, has suggested that the most important step in preventing late IPO is to maximize removal of LECs and cortex at the time of cataract surgery.24 This is best accomplished with copious hydrodissection as well as meticulous cortical cleanup and capsular polishing.

Prior to beginning phacoemulsification, additional Viscoat is injected to protect the endothelium. Then, sodium hyaluronate 1% is instilled above the nucleus to produce a soft shell within which emulsification will be performed. It is critical to use one of the latest generation phacoemulsifiers with a tip that allows maximal control over intraocular fluid dynamics. I prefer the Series 20000 Legacy (Alcon) in conjunction with a Kelman-MacKool tip. I use the 45° Kelman-MacKool tip for nuclear densities of +3 or greater and the 30° tip for softer nuclei. It is important to carefully insert the tip through the snug wound to avoid stripping the Descemet membrane adjacent to the wound or inadvertent contact with the endothelium or other ocular structures.

I perform phacoemulsification in a virtually watertight environment and maintain control over the anterior chamber fluidics. The height of the irrigation fluid bottle should be adjusted as needed to maintain stable chamber dynamics throughout the procedure. First, the anterior epinucleus is removed to make more room in the crowded anterior chamber. Next, a groove is created, beginning temporally to the center of the nucleus and proceeding nasally, with deep and peripheral grooving facilitated by maximal dilation. During grooving, ultrasound power is increased as dictated by nuclear density until efficient phacoemulsification is performed. A wide trough is created to maximize the amount of material removed in a true endocapsular fashion and to reduce the size of the pieces to be removed after nucleofractis. A phaco tip and a sideport instrument (e.g., a Beckert nucleus rotator) are used to generate a balanced torque-couple to rotate the nucleus without linear force. The nucleus is rotated 180° to allow extension of the trough. Harder nucleii may require several rotations to create a deep enough groove that will allow cracking of the nucleus without zonular stress. Patience, gentleness, and supplementation of viscoelastic are vital in preserving the delicate structure of the small anterior segment.

Once initial nucleofractis is completed, the surgeon can either switch to a chopping technique or continue with nucleofractis. Ultrasound power is lowered and removal of nuclear quadrants should be performed in the center of the capsular bag, with material fed into the phaco tip with the sideport instrument. If necessary, viscoelastic can be supplemented through the sideport. Removal of the last piece of nucleus from the bag should be performed at the level of the iris plane using "slow motion" parameters with low vacuum because these eyes may have weakened zonules and floppy capsules.

Following phacoemulsification, while the surgical assistant changes to an automated irrigation and aspiration (I&A) handpiece, additional Shugarcaine is instilled through the sideport to maximize patient comfort and cooperation throughout the rest of the procedure. I prefer an angled 45° I&A tip and I lower aspiration flow rate when the capsule is floppy and/or zonular laxity is present. The entire posterior capsule must be polished and all cells aspirated from the equator and undersurface of the anterior capsule. Various capsular polishing instruments can be used at this stage of the procedure. In the event of extreme capsular and/or zonular fragility, one or both lenses can be implanted to support the capsular bag and zonule before removing any recalcitrant equatorial or subincisional cortex.

Prior to IOL insertion, I fill the capsular bag with sodium hyaluronate 1%, followed by Viscoat instilled proximally to internally tamponade the wound and sideport. My preferred technique involves injection of a pair of plate haptic IOLs (e.g., the AA4204VL) into the capsular bag. When implanting the second IOL, it is important not to engage the first IOL and thereby stress the zonule. All viscoelastic should be removed from the eye at the conclusion of the case, especially viscoelastic behind the posterior optic and in the interface between the lenses. Once all viscoelastic has been aspirated, the haptics are then aligned perpendicularly; I spin the IOLs with the I&A tip to achieve this positioning.

For looped lenses, if a large capsulorrhexis strategy is chosen, haptic positioning should be used to maximize clearance of the anterior capsular remnant from the anterior optic and interface between the IOLs. Positioning can be either parallel or perpendicular, depending on the size, shape, and centration of the capsulorrhexis. If a bag/sulcus strategy is selected, the IOLs should be positioned with haptics perpendicular to each other to maximize separation between the optics, which may be the tertiary variable (to optic material and capsulorrhexis size) in the pathogenesis of IPO/ILO. Finally, if two looped lenses are placed with both haptic pairs inside the capsular bag with an overlapping capsulorrhexis, the anterior optic can be prolapsed through the capsulorrhexis and captured in the sulcus.

Miotics are not routinely used during the procedure. The stroma of the main incision and sideport is hydrated and wound competency is tested. It is imperative that wound integrity is never compromised, as postoperative wound leak and hypotony would impose an extremely high risk for late uveal effusion. If an air bubble is placed, it should be less than 25% of the anterior chamber volume as pupillary block has been reported following air bubble placement.25

Prophylactic sclerotomies are not performed because the tight incision minimizes the chance of intraoperative effusion. Careful serial dilated exams should be performed to prevent development of persistent postoperative effusion; if necessary, scleral windows can be created in a subsequent procedure. Spontaneous choroidal effusion and retinal detachment in nanophthalmos may be slow or even nonprogressive. 26 Thus, conservative initial management is indicated.

Management of Complications
I have encountered only one major intraoperative or short-term postoperative complication in my first 105 cataract extractions from nanophthalmic eyes; iatrogenic zonular dialysis resulted from the optic of the second plate-haptic IOL which engaged the first IOL during injection.

In the event of a complication, a surgeon must remain calm and avoid compromising the integrity of the wound. If a ruptured posterior capsular cannot provide sufficient support, an intact capsulorrhexis may allow sulcus fixation of a pair of AcrySof MA60BM or MA50BM IOLs. Insufficient support for a posterior chamber IOL significantly complicates the management. If the white-to-white diameter is less than 11 mm, the eye is too small for a standard anterior chamber lens and transscleral sulcus suturing of the lenses would be required. I use foldable acrylic lenses to minimize wound size. Depending on a surgeon's experience, the best approach in this situation may be to leave the eye aphakic and refer the patient for a subsequent secondary implantation. In the event of a serious complication or a potentially incompetent wound, prophylactic posterior sclerotomies should be performed and the patient should be closely monitored postoperatively.

Postoperative Regimen
Postoperatively, the preoperative antibiotic and NSAIDs are continued four times a day and a topical steroid is added to the regimen four times a day. The IOPs of patients with glaucoma are checked 4 to 6 hours postoperatively. In the event of a significant elevation in IOP, the eye is "burped" by depressing the posterior lip of the paracentesis at the slit lamp. Antibiotics are discontinued after 1 week, at which time the NSAID dosage is reduced to two times daily. Spectacles are prescribed 4 weeks postoperatively after a careful dilated examination is performed. Steroids are tapered and the NSAID is used until finished.

Cataract extraction using the above technique is curative with regard to narrow angles and improves IOP control in most cases. Eyes with persistent IOP elevation can often benefit from laser trabeculoplasty, because gonioscopic access to the angle would then be possible in these eyes.

I examine all polypseudophakic patients every 4 to 6 months. At each visit, I perform a widely dilated examination and inspect the interface between the IOLs for any signs of IPO/ILO. The relationship of the capsulorrhexis margin to the optic margins is noted and diagramed. In the future, wafer-thin, foldable, high-powered IOLs utilizing a diffractive technology may supplant the need for piggyback implantation in cases of extreme ametropia.

References

  1. Singh OS, Simmons RJ, Brockhurst RJ, Trempe CL. Nanophthalmos: A perspective on identification and therapy. Ophthalmology. 1982;89:1006-1012.


  2. Brockhurst RJ. Nanophthalmos with uveal effusion. A new clinical entity. Arch Ophthalmol. 1975;93:1989-1999.


  3. Othman MI, Sullivan SA, Skuta GL, et al. Autosomal dominant nanophthalmos (NNO1) with high hyperopia and angle-closure glaucoma maps to chromosome 11. Am J Hum Genet. 1998;63:1411-1418.


  4. Jin JC, Anderson DR. Laser and unsutured sclerotomy in nanophthalmos. Am J Ophthalmol. 1990;109:575-580.


  5. Gayton JL, Sanders VN. Implanting two posterior chamber intraocular lenses in a case of microphthalmos. J Cataract Refract Surg. 1993;19:776-777.


  6. Holladay JT, Gills JP, Leidlein J, Cherchio M. Achieving emmetropia in extremely short eyes with two piggyback posterior chamber intraocular lenses. Ophthalmology. 1996;103:1118-1123.


  7. Shugar JK, Lewis C, Lee A. Implantation of multiple foldable acrylic posterior chamber lenses in the capsular bag for high hyperopia. J Cataract Refract Surg. 1996;22:1368-1372.


  8. Shugar JK. Piggyback acrylic posterior chamber lenses: Omniopia? Presented at the American Society for Cataract and Refractive Surgery Annual Symposium. Boston, Mass. April 27, 1997.


  9. Shugar JK, Schwartz T. Interpseudophakos Elschnig pearls associated with late hyperopic shift: A complication of piggyback posterior chamber intraocular lens implantation. J Cataract Refract Surg. 1999;25:863-867.


  10. Gayton JL, Apple DJ, Peng Q, et al. Interlenticular opacification: A clinicopathological correlation of a new complication of piggyback posterior chamber intraocular lenses. J Cataract Refract Surg. 2000;26:330-336.


  11. Shugar JK, Keeler S. Inter-pseudophakos intraocular lens surface opacification as a late complication of piggyback acrylic posterior chamber intraocular lens implantation. J Cataract Refract Surg. 2000;26:448-455.


  12. Stasiuk R. Interface Elschnig pearl formation with piggyback implantation (letter). J Cataract Refract Surg. 2000;26:158-159.


  13. Shugar, JK. Inter-pseudophakos opacification. Invited discussion at the American Academy of Ophthalmology meeting. Orlando, Fla. October 25, 1999.


  14. Shugar JK. Piggyback IOL implantation: Fifty-seven month experience. Presented at the American Society for Cataract and Refractive Surgery annual symposium. Boston, Mass. May 20, 2000.


  15. Grabow HB. Polypsuedophakia. Presented at the American College of Eye Surgeons Annual Meeting. Orlando, Fla; 1996.


  16. Shugar JK. Interpseudophakos opacification and interlenticular membrane formation. Presented at the PCO Symposium at the American Society for Cataract and Refractive Surgery annual symposium. Boston, Mass. May 23, 2000.


  17. Written communication. The American Society of Cataract and Refractive Surgeons Internet Cataract Discussion Group. May 1999.


  18. Chang D. Achieving a large capsulorhexis for piggyback IOLs. Presented at the Symposium on Cataract, IOL, and Refractive Surgery at the American Society for Cataract and Refractive Surgery Annual Symposium. Boston, Mass; May 2000.


  19. Shugar JK. YAG laser lysis of interpseudophakos opacification. Presented at the American Society for Cataract and Refractive Surgery annual symposium. Boston, Mass. May 20, 2000.


  20. Werner L, Shugar JK, Pandey S, Escobar-Gomez M, Visessook N, Apple DJ. Opacification of piggyback IOLs associated with an amorphous material attached to their surfaces. J Cataract Refract Surg. 2000;26:1612-1619.


  21. Shugar JK. 'Shugarcaine' lessens burning sensation. Ocular Surgery News. 1998;1: 13.


  22. Shugar JK. Cataract surgery in microphthalmos. In: Buratto L, Osher RH, Masket S, eds. Cataract Surgery in Complicated Cases. 2000;90-93.


  23. Shugar JK. Cataract surgical problem: Response #9. J Cataract Refract Surg. 2000;26:1711-1713.


  24. Apple DJ. PCO: Etiology and prevention. Piggyback Study Group Special Conference 1. Ft. Worth, Texas. May 22, 1999.


  25. Shugar JK. Pupillary block, angle closure glaucoma produced by an anterior chamber air bubble in a nanophthalmic eye [letter]. Arch Ophthalmol. 1997;115:432.


  26. Han L, Cairns JD. Nanophthalmos with longstanding choroidal effusion and serous retinal detachment. Aust N Z J Ophthalmol. 1997;25:181-183.


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