PRESBYOPIC IOLS AND INTRAOPERATIVE PUPIL DILATATION
| ACCOMMODATING IOLs—Marian S. Macsai, MD, Professor and Vice-Chair, Department of Ophthalmology, Northwestern University Feinberg School of Medicine, and Chief, Division of Ophthalmology, Evanston Northwestern Healthcare, Chicago |
| Intraocular lens (IOL) review: single-vision IOL—inserted into capsular bag; brings distant vision into focus; multifocal/ diffractive IOL—causes multiple images to hit retina; early versions caused significant blur, and brain had to learn which focal point correct; accommodating IOL (Crystalens)—manufacturer claims lens provides full range of distant, intermediate, and near vision; single point of focus that responds to accommodative reflex (contraction of ciliary muscle) |
| Crystalens IOL: design—plate-style lens with hinges that allow forward and backward movement; haptics seat lens; 4.5- mm optic; lens lies against posterior capsule; surgery—lens floppy, so special forceps required; lens centers by itself; important to remove viscoelastic from behind optic |
 | Study: masked randomized observation of 112 patients with bilaterally implanted IOLs (56 in Crystalens group, 56 in monofocal IOL group); patient characteristics—Crystalens patients slightly younger; postoperative time 6 mo; monocular best corrected distance visual acuity (BCDVA) same for both groups; refractive spherical equivalent slightly better in Crystalens patients; best corrected near visual acuity (BCNVA) same for both groups; best corrected distance visual acuity (BCDVA) slightly better in Crystalens patients; uncorrected visual acuities—uncorrected distance visual acuity (UCDVA) 20/30 for monofocal patients, 20/25 for Crystalens patients; uncorrected near visual acuity (UCNVA) J6 for monofocal patients, J2 for Crystalens patients; binocular distance and near vision slightly better in Crystalens patients; measured accommodation—dynamic retinoscopy measured 2.4 diopters (D) in Crystalens patients and 0.90 D in monofocal patients; monofocal defocus measured 1.74 D in Crystalens patients and 0.75 D in monofocal patients; monocular near point of accommodation (NPA) measured 4.78 D in Crystalens patients and 1.23 D in monofocal patients; binocular defocus measured 1.96 D in Crystalens patients and 0.91 D in monofocal patients; binocular NPA measured 5.79 D in Crystalens patients and 1.5 D in monofocal patients; binocular UCNVA—100% of Crystalens patients J3 or better; some monofocal patients J2, some J3 |
| ReSTOR IOL: apodized diffractive IOL; foldable; one-piece acrylic 13 mm in diameter |
| Food and Drug Administration (FDA) data: monocular UCDVA 1 yr postoperative—for 20/40 or better, Crystalens and ReSTOR performed similarly; intermediate vision—100% of Crystalens patients 20/40 or better (98% of patients 20/25 or better); 67% of ReSTOR patients 20/40 or better; uncorrected binocular vision 1 yr postoperative—similar results in 20/40 range; Crystalens slightly better in 20/25 range; UCNVA 1 yr postoperative—binocular Crystalens better than ReSTOR (binocular ReSTOR achieves similar results to monocular Crystalens at J1, J2, and J3); ReSTOR FDA warning— 28% of patients have trouble driving at night; in night-driving simulator, ReSTOR patients had to be 40 ft closer than patients with standard monofocal lens to be able to read sign or hazard warning; halo—Crystalens better than standard IOL, ReSTOR, and Array; glare (monocularly implanted subjects) and night vision problems—ReSTOR performed better than Array, but not as well as Crystalens |
| Crystalens IOL vs ReSTOR IOL: different A-constant; both require central capsulorrhexis; Crystalens inserted with forceps, ReSTOR with shooter; Crystalens requires closure of wound and paracentesis if not watertight; ReSTOR implanted using standard acrylic cataract surgery; ReSTOR can be placed in sulcus, Crystalens cannot; different lengths (Crystalens 11.5 mm, ReSTOR 13 mm) |
| The “right” patient: motivated, well informed, and interested in quality of vision; determine patient’s requirements, eg, editor probably wants vision set for near; important to have realistic expectations |
| Postoperative expectations after Crystalens implantation: pupillary dilatation (due to use of atropine for temporary paralysis of ciliary body muscle) causes much glare and halo in immediate postoperative period |
| Patients to avoid: patients who demand perfect vision or freedom from spectacles, not willing to accept complications of cataract surgery, or demand immediate results (results with Crystalens get better over time) |
| Considerations: Crystalens not evaluated in patients <50 yr of age; effect of vitrectomy unknown; some patients still require glasses for certain tasks; posterior capsulotomies using yttrium-aluminum-garnet (YAG) laser should be delayed until 12 wk after implantation; YAG opening should be 4 mm |
| Conclusion: Crystalens restores some accommodation at 6 mo; night vision concerns with ReSTOR lens; speaker believes surgical procedure for implantation of Crystalens slightly more challenging than for ReSTOR |
| PRESBYOPIC, MULTIFOCAL, AND ACCOMMODATING IOLs—Steven S. Bylsma, MD, Assistant Clinical Instructor, Jules Stein Eye Institute, David Geffen School of Medicine at the University of California, Los Angeles, and Ophthalmologist, Shepherd Eye Center, Santa Maria, California |
Array IOL | Design: multifocal IOL; central distance-dominant zone; alternates between distance and near focus; optic edge gives blur; 100% of patients have halo; 3.5 D add in optic (near zones give +3.5 D); patient needs to hold things closer for improved vision; 50% of light dedicated to distance vision, 30% for near, and 13% for intermediate; 41% of Array patients independent of spectacles |
| Consequences of design: near vision improves if pupil slightly dilated; bright light can cause pupil to eliminate near zone, leading to loss of close-up vision; best near vision achieved at distance of 12 in; decrease in visual acuity as contrast level decreases |
| Patient consultation: important to prepare patient for likely outcome, eg, halo, glare; important to screen patients; hyperopes benefit most; some patients experience neuroadaptation delay, where brain takes time to learn which of 2 focal points intended object of regard |
ReZoom IOL | Design: acrylic lens, featuring Balanced View Optics and OptiEdge; range in size from 6 mm to 13 mm |
| Balanced View Optics: aims to obviate need to turn light down at night and prevent halo (which comes from outer zones); optic has slightly bigger zone 2 for near vision and much bigger zone 3 for distance, which results in decrease of outer near zone (zone 4) by 50% to 60%; overall, increased distance focus in dim light (as pupil dilates, patients see more distance and have reduced halo) |
| OptiEdge: rounded anterior edge reduces internal reflection; square posterior surface edge facilitates posterior capsule opacification; sloping side edge minimizes edge glare |
| Three-piece design: assists centration; lens can be placed in sulcus |
| ReZoom IOL vs Array IOL: different material (ReZoom made of acrylic); ReZoom should produce less halo; aspheric transition between zones said to give increased intermediate visual range with ReZoom; both refractive IOLs with 2.5 D add and can be placed in sulcus; price—Array costs $150 to $200; ReZoom costs $900 per lens |
| Use of spectacles: ReZoom package insert states 92% of patients never or occasionally wear glasses (93% of patients independent of spectacles for distance and intermediate, 81% for near); note—ReZoom did not go through FDA trial; lens approved using European data and as upgrade to Array |
| Light distribution: 100% of light rays available with refractive IOL, compared to 82% with diffractive IOL; theoretical calculations by manufacturer of ReZoom state that available light rays for 5-mm pupil for near vision far greater with ReZoom than with ReSTOR |
| ReZoom IOL vs ReSTOR IOL: similar pricing provides same economic opportunities for surgeons; both acrylic; speaker believes both give distance and near visual acuity; different platforms may create difference in immediate halo and other dysphotopsias |
Crystalens IOL | Design: accommodative lens that changes position in eye; has hinge and small 4.5-mm optic (longer haptics and smaller optic gives more anterior-posterior translation); functions based on theory that pressure gradient forms inside eye upon accommodative effort and vitreous pressure pushes lens forward |
| Insertion: does not have injector; 4.5-mm optic can be easily pushed through 3.5-mm incision; need to maintain posterior vaulting, so cycloplegia important to prevent lens assuming anterior position |
| Considerations: takes time to realize benefits; surgery requires practice; cannot use reading glasses; speaker’s clinical experience has not matched encouraging FDA data |
ReSTOR IOL | Design: apodized IOL that focuses light for near vision using only central portion of optic; eliminates halo glare when pupil dilated, allowing lights to be turned up to read |
| Light energy: even with only 82% of light rays available inside eye, light more than sufficient due to low cone threshold |
| Spectacle freedom: according to FDA submission data, 80% of ReSTOR patients never wear spectacles |
| Considerations: target for ReSTOR +0.25 D, so better to be at +0.5 D than -0.5 D; halo and glare still possible, but should be less than standard monofocal |
| Conclusions: hyperopes best candidates; need to manage astigmatism; important to select patients carefully and explain alternatives; accurate biometry key to success for all IOLs; ensure clean surgery and well-centered IOL |
| NEW METHODS FOR INTRAOPERATIVE CHEMICAL AND MECHANICAL PUPIL DILATATION —Dr. Bylsma |
| Increased risk of small pupil: if pupil not enlarged during cataract surgery, need to make small capsulorrhexis, which can lead to anterior capsular phimosis; important to polish underside of anterior capsule in cases of small capsulorrhexis (<5 mm) to prevent capsular phimosis; intraoperative risk—visualization; manipulation; bleeding; postoperative risk— atonic pupil (can be prevented with appropriate pupil stretching mechanisms) |
| Causes of small pupil: age primary cause; diabetes; synechiae; inflammation; previous surgery |
| Pupil size requirements for surgery: <4 mm—too small; 5 mm—surgery can be performed but better to dilate; 6 mm— acceptable, with additional dilation depending on case |
Mechanical Dilatation | Techniques: sphincterotomy—minute incisions made around pupillary sphincter allow pupil to open; pupil never comes back to normal; Beehler pupil dilator—more commonly used than sphincterotomy; speaker’s preferred method; others—2-instrument stretch; viscoelastic, eg, Healon 5 (sodium hyaluronate), can open pupil to suboptimal-to-acceptable level |
| Atonic pupil: if pupil mechanically stretched fully open, it will never come back down and atonic pupil will result; precautions—do not stretch pupil out to periphery; speaker has found stretching pupil three quarters of way and holding best method; miotic (eg, Miochol) used at end of surgery to constrict pupil; spike in intraocular pressure could result in atonic pupil from ischemia of dilator muscle |
| Hooks: hold iris out of way; can pull iris anteriorly, exposing pigmented epithelium of iris (loss of pigment leads to transillumination defect); take care not to have posterior iris epithelium presented to phaco tip; especially helpful in preventing iris prolapse in floppy iris syndrome |
| Rings: Morcher and Perfect Pupil available; slide around edge of pupil and physically hold it out; when removed, pupil returns to starting level |
| Beehler pupil dilator: available in 2 forms, 3-prong and 2-prong; 2-prong has smaller profile for smaller incisions; hook attaches to proximal iris; iris stretched and held in place; viscoelastic aids technique; miotic (eg, Miochol) used at end of surgery to constrict pupil |
Pharmacologic Dilatation | 10% phenylephrine solution: can induce cardiac arrest in patients with hypertension, especially if pledget used; systemic reaction can result from local ocular application; also increases punctate keratopathy, which can affect view during cataract surgery |
| Nonsteroidal anti-inflammatory drugs (NSAIDs): used preoperatively to help prevent constriction of pupil intraoperatively |
| Lidocaine/epinephrine solution: new pharmacologic method for intraoperative dilatation; fewer medications required preoperatively, so more comfortable for patients; visual recovery slightly faster for patients who do not wear eye patch after surgery; contains 1% lidocaine with 1:100,000 epinephrine; lidocaine paralyzes constrictor and epinephrine dilates dilator; commonly achieves only suboptimal dilatation; works better for lighter irises; younger patients have better results; pupil dilates quickly, then stops (full effect realized within 30 seconds); effective if directed just inside eye, past Descemet’s membrane |
Other Iris and Pupil Issues | Floppy iris syndrome: tamsulosin HCl [Flomax] (systemic α-1 antagonist that relaxes smooth muscle; used for benign prostatic hyperplasia and female urinary retention) potential cause of intraoperative floppy iris syndrome; same receptors in smooth muscle of prostate and bladder present in pupil dilator muscle; syndrome triad consists of floppy iris that billows with normal irrigation, propensity for iris to prolapse, and progressive pupillary constriction; prevention— recommendations include use of extra viscoelastic, low-flow fluidics, and iris retractors as needed |
| Artifical iris: available products include iris diaphragms, rings, sector rings for focal iris atrophy, artificial pupils, and colored irises for patients with aniridia |
| Iridoplasty: successful at correcting widely dilated, atonic pupils resulting from mechanical stretch |
Educational Objectives
| The goal of this program is to educate the listener about presbyopic intraocular lenses (IOLs) and intraoperative pupil dilation. After hearing and assimilating this program, the clinician will be better able to: |
| 1. Review the empirical data comparing accommodating IOLs to standard monofocal IOLs. |
| 2. Describe the differences between the various presbyopic IOLs. |
| 3. Discuss the expected clinical results for each IOL. |
| 4. Describe the various techniques of intraoperative pupil dilation. |
| 5. Avoid an atonic pupil after mechanical pupil dilation. |
Discussed on This Program
Phenylephrine HCl [several trade names] Sodium hyaluronate [several trade names] Tamsulosin HCl [Flomax]
Suggested Reading
Akman A et al: Comparison of various pupil dilatation methods for phacoemulsification in eyes with a small pupil secondary to pseudoexfoliation. Ophthalmology 111(9):1693, 2004; Alio JL et al: Near vision restoration with refractive lens exchange and pseudoaccommodating and multifocal refractive and diffractive intraocular lenses: comparative clinical study. J Cataract Refract Surg 30(12):2494, 2004; Chuang LH et al: Efficacy and safety of phacoemulsification with intraocular lens implantation under topical anesthesia. Chang Gung Med J 27(8):609, 2004; Claoue C: Functional vision after cataract removal with multifocal and accommodating intraocular lens implantation: prospective comparative evaluation of Array multifocal and 1CU accommodating lenses. J Cataract Refract Surg 30(10):2088, 2004; Hirowatari T et al: Evaluation of a new preoperative ophthalmic solution. Can J Ophthalmol 40(1):58, 2005; Jacobi PC et al: Multifocal intraocular lens implantation in patients with traumatic cataract. Ophthalmology 110(3):531, 2003; Jacobi PC et al: Multifocal intraocular lens implantation in prepresbyopic patients with unilateral cataract. Ophthalmology 109(4):680, 2002; Leyland MD et al: Prospective randomised double-masked trial of bilateral multifocal, bifocal or monofocal intraocular lenses. Eye 16(4):481, 2002; Marchini G et al: Ultrasound biomicroscopic changes during accommodation in eyes with accommodating intraocular lenses: pilot study and hypothesis for the mechanism of accommodation. J Cataract Refract Surg 30(12):2476, 2004; Montes-Mico R, Alio JL: Distance and near contrast sensitivity function after multifocal intraocular lens implantation. J Cataract Refract Surg 29(4):703, 2003; Pineda-Fernandez A et al: Refractive outcomes after bilateral multifocal intraocular lens implantation. J Cataract Refract Surg 30(3):685, 2004; Rana A et al: Understanding the accommodating intraocular lens. J Cataract Refract Surg 29(12):2284, 2003; Sen HN et al: Quality of vision after AMO Array multifocal intraocular lens implantation. J Cataract Refract Surg 30(12):2483, 2004; Stachs O et al: Potentially accommodating intraocular lenses--an in vitro and in vivo study using three-dimensional high-frequency ultrasound. J Refract Surg 21(1):37, 2005; Vargas LG et al: Performance of the 1CU accommodating intraocular lens in relation to capsulorhexis size. J Cataract Refract Surg 31(2):363, 2005; Yuguchi T et al: Pupillary functions after cataract surgery using flexible iris retractor in patients with small pupil. Jpn J Ophthalmol 43(1):20, 1999.
Faculty Disclosure
In adherence to ACCME guidelines, the Audio-Digest Foundation requests all lecturers to disclose any significant financial relationship with the manufacturer or provider of any commercial product or service discussed. For this issue, the following has been disclosed: Dr. Bylsma is a consultant for STAAR Surgical.
Dr. Macsai was recorded at the 28th Annual UC Davis Ophthalmology Symposium: Cataract Surgery From A to Z, presented May 13-14, 2005, by the University of California, Davis, Health System and held in Sonoma, California. Dr. Bylsma was recorded at the 25th Annual Current Concepts of Ophthalmology, presented July 16, 2005, by the San Diego Eye Bank and held in San Diego. The Audio-Digest Foundation thanks the speakers and the sponsors for their cooperation in the production of this program.
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