Stephen S. Lane

Optical performance of 3 intraocular lens designs in the presence of decentration

Purpose: To study the theoretical optical performance of 3 intraocular lens (IOL) designs in the presence of IOL decentration. Setting: Optics Center, Bausch & Lomb, Rochester, New York, USA. Methods: A ray‐tracing program was used to evaluate the effect of IOL decentration on the optical performance of 3 silicone IOLs (LI61U, Bausch & Lomb; Tecnis Z9000, Advanced Medical Optics; and a new aberration‐free IOL [SofPort AO, Bausch & Lomb]) in an experimental model eye. The study was done using pupil diameters of 3.0 mm, 4.0 mm, and 5.0 mm and IOL decentrations of 0 mm, 0.25 mm, 0.50 mm, 0.75 mm, and 1.00 mm. The modulation transfer functions were computed and plotted. A Monte Carlo simulation analysis with 1000 trials with IOL decentration randomly varying for each pupil size was performed. Results: Decentration of LI61U and Tecnis Z9000 IOLs led to asymmetrical higher‐order aberrations that adversely affected the optical performance of the model eye; performance was not affected with the aberration‐free IOL because it lacks inherent spherical aberration. Optical performance with the aberration‐free IOL was better than with the LI61U IOL as the former has less spherical aberration and did not introduce other aberrations when decentered. Performance with the aberration‐free IOL was better than with the Tecnis Z9000 IOL for 3.0 mm, 4.0 mm, and 5.0 mm pupils when decentration exceeded 0.15 mm, 0.30 mm, and 0.38 mm, respectively. Performance with the LI61U IOL was better than with the Tecnis Z9000 IOL for 3.0 mm, 4.0 mm, and 5.0 mm pupils when decentration exceeded 0.3 mm, 0.5 mm, and 0.5 mm, respectively. Monte Carlo simulations showed the expected postoperative results of the LI61U IOL and aberration‐free IOL would be repeatable and predictable, whereas the outcomes with the Tecnis Z9000 IOL would vary widely. Conclusions: The optical performance of the model eye was not affected by decentration of an aspheric IOL designed to have no inherent spherical aberration. With decentration, the performance with the new IOL was better than with a conventional spherical IOL and an aspheric IOL designed to offset the spherical aberration of an average cornea.

Excimer Laser Photorefractive Keratectomy in High Myopia: A Multicenter Study

Excimer photorefractive keratectomy was performed at three centers on 16 highly myopic eyes (8 diopters [D] or more) and followed up for 6 months. Ablation depths ranged from 137 to 230 microns. The preoperative spherical equivalent of myopia ranged from -8.62 D to -14.50 D (mean +/- SD, -11.57 +/- 1.62 D). Six months after surgery, the mean refraction (spherical equivalent) was -0.90 +/- 2.13 D. Eleven of 16 eyes achieved refractions within 2 D of that attempted. All eight patients at one site were treated with a maximum-beam diameter of 6.0 mm and were corrected to within 2 D of that attempted, and all were 20/40 or better uncorrected. Three of eight eyes at the other two sites were treated with a 5.5- or 5.6-mm maximum-beam diameter, which achieved corrections within 2 D of that attempted. The epithelium healed within 3 to 4 days, and there were no erosions. Mild subepithelial reticular haze, similar to that seen with excimer photorefractive keratectomy for lower myopia, was seen in all patients, with two patients experiencing more significant corneal haze. This peaked at 3 to 6 weeks and then gradually diminished. All but two patients had a return of their best corrected preoperative visual acuity to within one Snellen line at 6 months. This preliminary study shows excimer photorefractive keratectomy to be a promising surgical treatment for patients with higher myopia.

The AcrySof Toric Intraocular Lens in Subjects with Cataracts and Corneal Astigmatism: A Randomized, Subject-Masked, Parallel-Group, 1-Year Study

PURPOSE To compare the AcrySof Toric intraocular lens (IOL) and an AcrySof spherical control IOL and to investigate rotational stability of the AcrySof Toric IOL (Alcon Laboratories, Inc., Fort Worth, TX) in subjects with cataracts and preexisting corneal astigmatism. DESIGN Randomized, subject-masked, parallel-group, multicenter, 1-year study. PARTICIPANTS We included 517 subjects (Toric IOL, n = 256; control IOL, n = 261). METHODS Unilateral implantation of an AcrySof Toric or AcrySof spherical control IOL (spherical powers, 12.00-25.00 diopters [D]; cylinder powers 1.50, 2.25, or 3.00 D for corneal astigmatism correction of 0.75 to < 1.50, ≥ 1.50 to <2.00, and ≥ 2.00 D with no upper limit, respectively). No limbal relaxing incisions were permitted. MAIN OUTCOME MEASURES Visual acuity outcomes, IOL position, patient-reported spectacle use, and safety. RESULTS One year postoperatively, best spectacle-corrected distance visual acuity of ≥ 20/20 was 77.7% (Toric IOL) versus 69.2% (control IOL). Uncorrected distance visual acuity of 20/20 or better was 40.7% (Toric IOL) versus 19.4% (control IOL; P<0.05). Mean absolute residual refractive cylinder was 0.59 D (Toric IOL) versus 1.22 D (control IOL; P<0.0001). Mean rotation was < 4° (range, 0°-20°) for the Toric IOL. Six-month spectacle freedom was 61.0% (Toric IOL) and 36.4% (control IOL; P < 0.0001). Complications in both groups were few and were as would be expected with cataract surgery. CONCLUSIONS Favorable efficacy, rotational stability, distance vision spectacle freedom, and safety results support the use of the AcrySof Toric IOL for patients with cataracts and corneal astigmatism. FINANCIAL DISCLOSURE(S) Proprietary or commercial disclosure may be found after the references.

193-nm Excimer Photorefractive Keratectomy in High Myopia

PURPOSE To evaluate the refractive results of 193-nm excimer laser photorefractive keratectomy (PRK) performed on 48 highly myopic eyes in a multicenter study. METHODS A Visx 2015 or 2000 argon-fluoride excimer laser and a single-zone ablation technique were used. Postoperatively, eyes were treated with topical fluoromethalone for up to 5 months. Most eyes were treated with a 6.0- to 6.2-mm beam diameter after undercorrections and increased regression were noted with a 5.5-mm beam in earlier studies. Forty-eight eyes were treated for myopia, which was between -8.0 and -15.25 diopters (D) (spherical equivalent). The mean preoperative refraction was -11.2 D. Retreatment was performed after 6 to 16 months on 11 eyes for undercorrection. All eyes not retreated were followed for at least 12 months. RESULTS At 6 months, follow-up was available on 47 eyes. Of these eyes, 40% and 64% achieved corrections within 1 and 2 D of attempted correction, respectively. At 1 year, 60% of eyes attained 20/40 visual acuity or better uncorrected. Eleven patients (23%) were retreated between 6 to 16 months for undercorrection and/or regression. After retreatment, 47% and 81% of eyes achieved corrections within 1 and 2 D of attempted correction, respectively. At 1 year, 15% of eyes lost two lines of best-corrected visual acuity, and no eyes lost more than two lines. There was slightly more corneal haze seen in this group compared with the haze seen in patients undergoing PRK for low and moderate myopia. CONCLUSIONS These data show that excimer PRK can correct high amounts of myopia with reasonable stability after 6 months. Excimer PRK is an effective surgical treatment of severe myopia, but long-term follow-up is still needed to assess the stability of its effect.

Evaluation of the safety of prophylactic intracameral moxifloxacin in cataract surgery

PURPOSE: To evaluate posterior and anterior segment safety of an intracameral injection of moxifloxacin 0.5% ophthalmic solution as prophylaxis for endophthalmitis in patients having cataract surgery. SETTING: Three private practices, the University of Minnesota School of Medicine, Stillwater, Minnesota, and the University of Cincinnati, Cincinnati, Ohio, USA. METHODS: In this prospective randomized combined‐center open‐label trial, 57 eyes of 47 patients were treated with intracameral moxifloxacin (250 μg/0.050 mL) or an equal volume of balanced salt solution at the conclusion of cataract surgery with intraocular lens implantation. Safety parameters, including visual acuity, intraocular pressure, endothelial cell counts, corneal pachymetry, corneal clarity and edema, and anterior chamber cells and flare, were evaluated preoperatively and for 3 months postoperatively. RESULTS: Optical coherence tomography results showed no statistically significant differences between the 2 treatment groups preoperatively or at 3 months. There were also no statistically significant differences between the 2 treatment groups in all other parameters preoperatively or at 1 day, 2 to 4 weeks, or 3 months. No study‐related adverse events occurred. CONCLUSION: There was no increased safety risk associated with a 250 μg/0.050 mL intracameral injection of moxifloxacin, which appears to be safe in the prophylaxis of endophthalmitis after cataract surgery.

Penetrating Keratoplasty and Transscleral Fixation of Posterior Chamber Lens

We reviewed the outcome in 115 patients who underwent penetrating keratoplasty and transscleral fixation of a posterior chamber lens. One patient died soon after surgical procedures, and nine patients were lost to follow-up, leaving a cohort of 105 patients. Mean follow-up time was 26.8 months (range, six to 43 months). Visual acuity of 20/40 or better was found in 29 patients (27.6%) and 20/50 to 20/200 in 37 patients (35.2%). Reasons for poor visual outcome included cystoid macular edema in ten patients (9.5%), age-related macular degeneration in six patients (5.7%), and retinal detachment in four patients (3.8%). None of the patients developed lens decentration. There were no instances of hyphema and only one patient had a perioperative limited suprachoroidal hemorrhage. New-onset increase in intraocular pressure developed in 20 of 66 patients (30.3%). Analysis of the 39 patients with preoperative increase in intraocular pressure that required medical treatment demonstrated an improvement in 13 patients (33.3%), worsening in 12 patients (30.8%), and unchanged status in 14 patients (35.9%). The exposed haptic suture was covered by using one of the following three alternative methods: a conjunctival flap, a scleral flap, or a corneal tissue button. Exposure of the haptic suture through the conjunctiva was a complication in 21 patients (20%). Of these 16 (76.1%) occurred in the group with a conjunctival covering, five (23.8%) occurred in the group with a scleral flap, and none occurred in the corneal tissue button group. This study demonstrated that transscleral fixation of a posterior chamber lens is a viable option in the treatment of patients undergoing penetrating keratoplasty and intraocular lens implantation with absent capsular support.

Implantation of a Posterior Chamber Lens Without Capsular Support During Penetrating Keratoplasty or as a Secondary Lens Implant

We have devised a technique to fixate a posterior chamber lens in the ciliary sulcus when no posterior capsular support exists. Our short-term follow-up of 22 eyes with lenses thus fixated has shown these eyes to be quiet and to have good pupillary motility after at least 3 months. We believe this new technique is a significant advancement in corneal and anterior segment surgery.

Prospective comparison of the effects of Occucoat, Viscoat, and Healon on intraocular pressure and endothelial cell loss

ABSTRACT We compared the effect of Occucoat (2% hydroxypropylmethylcellulose), Viscoat (sodium hyaluronate‐chondroitin sulfate), and Healon (sodium hyaluronate) on postoperative intraocular pressure (IOP) and endothelial cell damage. One hundred fourteen patients having planned extracapsular cataract extraction with posterior chamber lens implantation using a viscomaterial were prospectively randomized into one of five groups. Group I received Occucoat which was removed from the anterior chamber at the conclusion of surgery. Group H received Occucoat which was not removed (retained). Group III received Viscoat which was removed, Group IV received Viscoat which was retained, and Group V received Healon which was removed. No prophylactic ocular hypotensive medications were given. Intraocular pressure was measured at four hours, 24 hours, one week, one month, three months, and one year postoperatively. Compared to preoperative IOP, all groups had a significant IOP increase at four hours. All but the Viscoat removed group (Group III) showed a statistically significant increase at 24 hours postoperatively (P<.05). No group had a significant increase at one week or later. Specular microscopy showed no significant difference in cell loss between any of the groups at three months or within each group when compared to preoperative cell counts (P>.1).

Performance of presbyopia-correcting intraocular lenses in distance optical bench tests

PURPOSE: To compare the optical performance of 6 presbyopia‐correcting intraocular lenses (IOLs) of different designs (accommodating or multifocal and aspheric or spheric). SETTING: Alcon Laboratories, Inc., Fort Worth, Texas, USA. METHODS: The optical performance of 6 IOLs were compared using modulation transfer function (MTF) and the United States Air Force 1951 Resolution Target (AFT) testing. The IOLs included 3 spheric designs (Crystalens AT‐50SE, AcrySof ReSTOR SA60D3, and ReZoom NXG1) and 3 aspheric designs (AcrySof ReSTOR SN6AD3, Acri.Lisa 366D, and Tecnis ZM900). Tests were performed with a modified International Organization for Standardization (ISO) model eye with a 5.0 mm aperture at the distance focus. RESULTS: The ReSTOR aspheric IOL had the highest MTF values at all spatial frequencies, and the ReZoom IOL had the lowest MTF values at most spatial frequencies. The ReSTOR aspheric IOL produced the image with the highest resolution on the AFT test; the Tecnis and the ReZoom IOLs produced the images with the poorest resolution. The Acri.Lisa multifocal IOL was second to the ReSTOR aspheric IOL on the MTF test and had high resolution on the AFT test. The accommodating Crystalens performed poorly on the MTF test but had the second highest resolution on the AFT test. CONCLUSIONS: The AcrySof ReSTOR SN6AD3 aspheric IOL showed superior optical properties, demonstrated in MTF and AFT optical bench testing, among 6 presbyopia‐correcting IOLs including the monofocal accommodating Crystalens. The Acri.Lisa IOL also performed well. The ReZoom IOL demonstrated the poorest overall optical quality.

Results One Year After Using the 193-nm Excimer Laser for Photorefractive Keratectomy in Mild to Moderate Myopia

As part of a clinical trial, photorefractive keratectomy using the VISX 2015 193-nm excimer laser was performed on 91 healthy eyes of 91 patients. Preoperative refractive errors (spherical equivalent) ranged from -1.00 to -7.50 diopters (mean, -4.16 +/- 1.41 diopters). No patient had more than 1 diopter of refractive astigmatism. Six months postoperatively, the average residual refractive error was +0.09 +/- 0.63 diopters (range, -2.13 to +1.63 diopters). Correction within 1 diopter of that attempted was attained in 85 eyes (93%). Uncorrected visual acuity of 20/40 or better was attained in 86 eyes (95%) and was 20/25 or better in 67 eyes (74%). At one year, follow-up information was available on 85 eyes of 85 patients. The average residual refractive error was -0.15 +/- 0.65 diopters (range, -2.50 to +1.63 diopters). Correction within 1 diopter of that attempted was attained in 85 eyes (93%). Uncorrected visual acuity was 20/40 or better in 83 eyes (98%) and was 20/25 or better in 68 eyes (80%). One patient lost three lines of best-corrected visual acuity because of corneal haze, dropping from 20/15 to 20/30, whereas all other patients returned to best-corrected visual acuity within one line of their preoperative best-corrected visual acuity. Photorefractive keratectomy with the 193-nm excimer laser appears to be a useful treatment modality for the reduction of mild to moderate myopia.