Images created in a model eye during simulated cataract surgery can be the basis for images perceived by patients during cataract surgery.

PURPOSE: To evaluate the images created in a model eye during simulated cataract surgery. PATIENTS AND METHODS: This study was conducted as a laboratory investigation and interventional case series. An artificial opaque lens, a clear intraocular lens (IOL), or an irrigation/aspiration (I/A) tip was inserted into the 'anterior chamber' of a model eye with the frosted posterior surface corresponding to the retina. Video images were recorded of the posterior surface of the model eye from the rear during simulated cataract surgery. The video clips were shown to 20 patients before cataract surgery, and the similarity of their visual perceptions to these images was evaluated postoperatively. RESULTS: The images of the moving lens fragments and I/A tip and the insertion of the IOL were seen from the rear. The image through the opaque lens and the IOL without moving objects was the light of the surgical microscope from the rear. However, when the microscope light was turned off after IOL insertion, the images of the microscope and operating room were observed by the room illumination from the rear. Seventy percent of the patients answered that the visual perceptions of moving lens fragments were similar to the video clips and 55% reported similarity with the IOL insertion. Eighty percent of the patients recommended that patients watch the video clip before their scheduled cataract surgery. CONCLUSIONS: The patients' visual perceptions during cataract surgery can be reproduced in the model eye. Watching the video images preoperatively may help relax the patients during surgery.

Prospective randomized comparison of DisCoVisc and Healon5 in phacoemulsification and intraocular lens implantation.

PURPOSE: To compare two ophthalmic viscosurgical devices (OVDs), DisCoVisc (viscous dispersive) and Healon5 (viscoadaptive), in terms of their overall clinical performance during phacoemulsification and intraocular lens (IOL) implantation. METHODS: In 323 patients (DisCoVisc; 157, Healon5; 166), the surgeons evaluated on a three-point scale, the maintenance of anterior chamber (AC) during continuous curvilinear capsulorhexis (CCC), maintenance of AC during IOL implantation, retention during phacoemulsification, ease of injection, facilitation of CCC, transparency during surgery, and ease of removal from the eye. The time needed to completely remove OVDs after IOL implantation was measured. Masked examiners measured intraocular pressure (IOP), corneal thickness, and corneal endothelial cell count up to 90 days postoperatively. RESULTS: DisCoVisc was assessed to be significantly better than Healon5 in maintenance of AC during CCC (P=0.0008, Cochran-Mantel-Haenszel test) and IOL implantation (P=0.0055), retention during phacoemulsification (P=0.0009), ease of injection (P<0.0001), facilitation of CCC (P<0.0001), transparency (P<0.0001), and ease of removal (P<0.0001). The washout time was 29.6+/-13.4 and 36.2+/-17.5 s in the DisCoVisc and Healon5 groups, respectively (P=0.0002, unpaired t-test). The mean endothelial cell loss was 1.8+/-8.7% in the DisCoVisc group and 3.8+/-8.3% in the Healon5 group (P=0.0358). There were no statistically significant between-group differences in IOP and corneal thickness. CONCLUSION: DisCoVisc was better retained in the eye during phacoemulsification and was easier to remove after IOL implantation. The corneal endothelial cell loss was significantly less with DisCoVisc than with Healon5. It was indicated that the whole surgical process can be efficiently covered by DisCoVisc alone.

Effect of laser in situ keratomileusis correction on contrast visual acuity.

PURPOSE: To evaluate the changes in contrast visual acuity (CVA) based on the amount of myopic correction with laser in situ keratomileusis (LASIK). METHODS: In this prospective study, patients with myopia ranging from -2.0 to -14.0 diopters (D) were divided into 2 groups: those with myopia less than -6.0 D (n = 20) and those with myopia greater than -6.0 D (n = 13). The CVA was measured preoperatively and 1 week and 1 and 3 months postoperatively using Variable Contrast Visual Acuity Charts. RESULTS: The patients with less than -6.0 D of myopia had a CVA decrease of 15% 1 week postoperatively, which recovered by 1 month, and a decrease of 2.5% 1 week and 1 month postoperatively, which recovered by 3 months. The patients with more than -6.0 D of myopia had a decrease of 15% and 2.5% at all postoperative times. CONCLUSIONS: After LASIK to correct myopia of greater than -6.0 D, there may be a persistent decrease in intermediate and low CVA. Patients should be informed preoperatively of this possible decrease in CVA.

Intact corneal epithelium is essential for the prevention of stromal haze after laser assisted in situ keratomileusis.

AIMS: To determine the effect of intact corneal epithelium on stromal haze and myofibroblast cell formation after excimer laser surgery. METHODS: Denuded epithelium alone, photorefractive keratectomy (PRK), laser in situ keratomileusis (LASIK), or LASIK with denuded epithelium was performed in rabbit eyes. Postoperative anterior stromal haze was assessed employing a standard scale. Immunohistochemical methods were used to detect alpha smooth muscle actin (alpha-SMA), a marker for myofibroblastic cells, and type III collagen in subepithelial corneal tissue. RESULTS: Three weeks after surgery, the presence of alpha-SMA positive long extended and spindle-shaped stromal cells, and synthesis of type III collagen were observed in the subepithelial stromal layer corresponding to corneal haze in PRK and LASIK with denuded epithelium, but not in denuded epithelium alone and LASIK. CONCLUSION: The intact corneal epithelium may play an important part curbing subepithelial haze and differentiation of myofibroblasts in corneal wound healing.

Clinical application of Er:YAG laser for the treatment of pterygium.

BACKGROUND AND OBJECTIVE: To evaluate the clinical application of Er:YAG laser for the treatment of pterygium. METHOD: Five patients (5 eyes) with pterygium, 2 primary cases and 3 retreatment cases, whose ages ranged from 44 to 68 years (mean 54.4 years), were treated with the Er:YAG laser. The optical system consisted of a fluorozirco-aluminate glass fiber and a handpiece tip made of quartz glass. The tip of the guiding probe was applied to the surface of the pterygium, where the laser beam was emitted. The radiant energy was set at 10 mJ with water spray. RESULT: The removal of pterygium was accomplished under topical anesthesia with a laser output approximate range from 50 to 100 shots. Complications such as corneal erosion or thinning of the sclera were not observed. However, recurrence was seen in the 3 retreatment cases. CONCLUSION: The Er:YAG laser system may be a clinically useful tool as a laser surgical knife for ocular tissue.

Iatrogenic cataract after laser-assisted in situ keratomileusis.

PURPOSE: To report a case of corneal opacity and iatrogenic cataract after laser-assisted in situ keratomileusis. METHOD: Case report. A 44-year-old man was initially seen with a traumatic cataract, corneal stromal opacity, and defect of the endothelium in the right eye after laser-assisted in situ keratomileusis performed by a plastic surgeon who had no ophthalmologic training. RESULTS: It was speculated that repeated ablations resulted in corneal perforation. We immediately performed phacoemulisification to remove the cataract and to prevent phacolytic glaucoma. However, visual acuity remained 20/200 because of the corneal stromal opacity, and penetrating keratoplasty was performed 2 months later, which improved best-corrected visual acuity to 20/30. CONCLUSIONS: This case demonstrated that laser-assisted in situ keratomileusis can cause devastating damage to the eye.

Treatment of severe ocular-surface disorders with corneal epithelial stem-cell transplantation.

BACKGROUND: Conditions that destroy the limbal area of the peripheral cornea, such as the Stevens-Johnson syndrome, ocular pemphigoid, and chemical and thermal injuries, can deplete stem cells of the corneal epithelium. The result is scarring and opacification of the normally clear cornea. Standard corneal transplantation cannot treat this form of functional blindness. METHODS: We performed and evaluated 70 transplantations of corneal epithelial stem cells from cadaveric eyes into 43 eyes of 39 patients with severe ocular-surface disorders and limbal dysfunction. Medical treatment had failed in all patients. The patients had a mean preoperative visual acuity of 0.004 (only being able to count the number of fingers presented by the examiner) in the affected eyes, which satisfies the criteria for legal blindness in most countries. In 28 eyes, we also performed standard corneal transplantation. Stem-cell transplantations were performed as many as four times on 1 eye if the initial results were not satisfactory; 19 eyes had multiple transplantations. Patients were followed for at least one year after transplantation. RESULTS: A mean of 1163 days after stem-cell transplantation, 22 of the 43 eyes (51 percent) had corneal epithelialization; of the 22 eyes, 7 eyes had corneal stromal edema and 15 eyes had clear corneas. Mean visual acuity improved from 0.004 to 0.02 (vision sufficient to distinguish the largest symbol on the visual-acuity chart from a distance of 1 m) (P<0.001). The 15 eyes in which the cornea remained clear had a final mean visual acuity of 0.11 (the ability to distinguish the largest symbol from a distance of 5 m). Complications of the first transplantation included persistent defects in the corneal epithelium in 26 eyes, ocular hypertension in 16 eyes, and rejection of the corneal graft in 13 of 28 eyes. The epithelial defects eventually healed in all but two of the eyes. CONCLUSIONS: Transplantation of corneal epithelial stem cells can restore useful vision in some patients with severe ocular-surface disorders.

Excimer laser-induced hydroxyl radical formation and keratocyte death in vitro.

PURPOSE: To characterize the type of reactive oxygen species (ROS) produced by excimer photoablation of aqueous solutions and to show the effects of ROS and antioxidants on corneal stromal cells in vitro. METHODS: Electron spin-resonance spectroscopy was performed using the spin-trapping agent 5,5-dimethyl-1-pyrroline N-oxide (DMPO) for the detection of the superoxide anion and the hydroxyl radical in an acellular DMPO solution irradiated with the excimer laser. Hydroxyl radicals were produced by the Fenton reaction in vitro by the mixture of hydrogen peroxide and ferrous iron (Fe2+), and the effects on cultured corneal fibroblasts were observed by fluorescent microscopy using the cell death marker, propidium iodide (PI) and TdT-mediated dUTP nick-end labeling (TUNEL). RESULTS: Excimer photoablation of a 1% DMPO solution produced a species-specific spin-trapping adduct for the hydroxyl radical ('OH), but not for the superoxide anion or other unidentified free radical. The signals were inhibited dose dependently by the hydroxyl radical scavenger dimethylsulfoxide (DMSO) and an L-ascorbic acid analogue, EPCK-1. The production of *OH in the supernatant of cultured rabbit corneal fibroblasts by the Fenton reaction caused an increase in PI (+) and TUNEL (+) cells by 90 minutes, which was significantly inhibited by the addition of DMSO. CONCLUSIONS: Hydroxyl radicals may be partly responsible for stromal fibroblast cell apoptosis after excimer photoablation.

Thermal effect on corneal incisions with different phacoemulsification ultrasonic tips.

PURPOSE: To evaluate the thermal effects of 3 phacoemulsification ultrasound (US) tips (standard, MicroTip, and Mackool) on the corneal incision based on the tip's position. SETTING: Department of Ophthalmology, Tokyo Dental College, Tokyo, Japan. METHODS: Thermal changes were recorded with an infrared thermal video during phacoemulsification in 18 porcine eyes. The 3 US tips were placed in 3 positions (primary, roofing, and flanking) in the corneal incision, and the resultant temperature changes were recorded. RESULTS: With the 3 US tips in the primary position, the temperature remained under 36 degrees C. When the tips were in the roofing position, a marked temperature increase (51.4 degrees C) was observed with the standard tip; with the MicroTip, a temperature increase occurred but was lower than with the standard tip; with the Mackool tip, the temperature remained stable. The temperature around the incision site increased with all tips when they were moved toward the corner of the incision, which resulted in direct contact with the silicone sleeve. This change was most obvious with the standard tip (temperature 51.5 degrees C), and a wound burn was observed. With the MicroTip, the temperature increase was moderate (44.2 degrees C), and the wound burn area was smaller. With the Mackool tip, the temperature increased the least (42.1 degrees C). CONCLUSION: The position of the US tips resulted in a temperature increase in the incision area and caused wound burn. Newly developed US tips could minimize this complication.

A new surgical technique for deep lamellar keratoplasty with single running suture adjustment.

PURPOSE: To improve the technique of deep lamellar keratoplasty. METHODS: For the recipient eye, a divide-and-conquer technique was applied to deep lamellar keratoplasty. After trephinization, the recipient cornea within the trephine was divided into four quadrants to facilitate lamellar dissection at approximately 70% depth. This procedure of division was continued until the Descemet membrane was exposed in the central area. The corneal graft was placed with an adjusted single running suture. Seventeen eyes were treated with this technique. RESULTS: In 17 eyes of 15 patients, the mean visual acuity 6 months or more after deep lamellar keratoplasty was 20/52 with eyeglass correction and 20/80 without eyeglass correction. At 6 months or more after deep lamellar keratoplasty, the mean +/- SD keratometric astigmatism in 17 eyes was 3.2 +/- 2.3 diopters. CONCLUSION: This technique facilitates deep lamellar keratoplasty and prevents high or excessive astigmatism after surgery.

Allergic conjunctivitis as a risk factor for regression and haze after photorefractive keratectomy.

PURPOSE: To analyze the relation between allergic conjunctivitis and the results of photorefractive keratectomy performed with an excimer laser in myopic eyes. METHODS: Fifty-seven myopic eyes in 57 Japanese patients were classified into three groups: a normal group (30 eyes of 30 patients), a treatment group composed of eyes with allergic conjunctivitis that were treated with fluorometholone and cromolyn sodium eyedrops from month 3 until the end of the 12- to 18-month follow-up period (16 eyes of 16 patients), and a no-treatment group composed of eyes with allergic conjunctivitis that received no allergic treatment until the end of the follow-up period (11 eyes of 11 patients). Preoperative and postoperative examinations included evaluation of corrected and uncorrected visual acuity and grading of corneal haze. RESULTS: In the no-treatment group, the mean corneal haze score +/- SD of 0.8 +/- 0.98 was significantly greater than the normal group score of 0.38 +/- 0.49 (P = .02). There was no significant difference in the haze score between the treated and normal groups. A refractive outcome of +/- 1 diopter was obtained in 30 (100%) of the 30 patients in the normal group, 15 (93.8%) of 16 patients in the treatment group, and four (36.4%) of the 11 patients in the no-treatment group. Visual acuity was 20/40 or better after photorefractive keratectomy in 30 patients (100%) in the normal group, 15 patients (93.8%) in the treatment group, and six patients (54.5%) in the no-treatment group. CONCLUSION: These findings suggest that untreated allergic conjunctivitis is a significant risk factor for haze and myopic regression after photorefractive keratectomy.

Elschnig pearl formation along the posterior capsulotomy margin after neodymium:YAG capsulotomy.

PURPOSE: To determine the incidence of Elschnig pearl formation along the capsulotomy margin (string of pearls) after neodymium:YAG (Nd:YAG) laser posterior capsulotomy and to elucidate its clinical features, predisposing factors, effect on visual function, and association with additional capsulotomy. SETTING: Keio University Hospital, Tokyo, Japan. METHODS: The records of 418 eyes that had had Nd:YAG posterior capsulotomy after cataract surgery were retrospectively reviewed. Of those, 315 were excluded for short follow-up (fewer than 12 months) or insufficient clinical examination data. In the remaining 103 eyes, the incidence of string of pearls was calculated, and its clinical features, predisposing factors, effect on visual function, and correlation with additional capsulotomy were evaluated. RESULTS: String of pearls was identified in 49 eyes (47.6%); 37 (75.5%) developed pearls within 1 year after Nd:YAG capsulotomy. The incidence was significantly higher in patients having intraocular lens implantation and continuous curvilinear capsulorhexis (CCC) than in those without (95.9 versus 61.1% and 97.9 versus 55.6%, respectively). No significant differences were found in patient age and sex, total Nd:YAG energy, and the presence of diabetes mellitus or high myopia. String of pearls caused visual disturbances in 17 eyes (34.7%). The rate of repeat capsulotomy was higher in patients with string of pearls than in those without (36.7 and 9.3%, respectively). CONCLUSIONS: String of pearls formation was a common and significant complication after Nd:YAG posterior capsulotomy. Intraocular lens implantation and CCC may promote its formation.

Evaluation of a zonal-progressive multifocal intraocular lens.

PURPOSE: To determine the clinical usefulness of a five-zone refractive multifocal intraocular lens. METHODS: After more than 1 year of follow-up, we evaluated the visual function of 22 patients (36 eyes) who had received the MPC-25NB intraocular lens for distance and near visual acuity, kinetic visual acuity, and near contrast sensitivity, and for patient satisfaction. RESULTS: Of 31 study eyes with less than 1.5 diopters of preoperative keratometric astigmatism, 28 (90.3%) achieved an uncorrected distance visual acuity of 20/40 or better; best-corrected distance visual acuity was 20/20 or better in 31 (86.1%) of 36 eyes. Near visual acuity with distance correction was 20/40 or better in 20 (60.6%) of 33 eyes. Kinetic visual acuity in these patients was comparable to that in patients with monofocal intraocular lenses. Distance visual acuity and near contrast sensitivity were below normal or within the low normal range. There was no significant difference in contrast visual acuity measured by variable contrast visual acuity charts between MPC-25NB and monofocal intraocular lens-implanted eyes (P > .05). Four (22.2%) of 18 patients did not require spectacles when the intraocular lens was implanted for emmetropia. Despite some complaints about near or night vision, all patients expressed satisfaction. CONCLUSIONS: The MPC-25NB lens provides a level of distance vision comparable to that of a monofocal intraocular lens and a useful level of near visual acuity without spectacles. However, we should carefully evaluate the indication for use of MPC-25NB in patients who require good near vision or night vision.

Clinical evaluation of a five-zone refractive multifocal intraocular lens.

PURPOSE: To evaluate the clinical performance of a five-zone refractive multifocal intraocular lens (AMO, model MPC-25NB, Array). METHODS: We performed a retrospective clinical trial of 31 cataract patients (mean age 64.3 years). The parameters studied were intraoperative and postoperative complications, distance and near visual acuity, spectacle use, decreased number of corneal endothelial cells, contrast sensitivity, percentage of glare disability, near binocular vision, and depth of focus. RESULTS: Intraoperatively, iris damage occurred in two eyes (4.2%), vitreous loss in one eye (2.1%), and consecutive rupture of Zinn's zonule and vitreous in one eye (2.1%). Postoperatively, posterior capsule opacification was observed in two eyes (4.2%), temporary intraocular pressure increase in one eye (2.1%), and cystoid macular edema in one eye (2.1%). Uncorrected distance visual acuity of 20/40 or better was achieved by 34 of 37 eyes (91.9%) with less than 1.5 diopters of preoperative keratometric astigmatism; best corrected distance acuity of 20/20 or better was achieved by 41 of 45 eyes (91.1%). Near visual acuity with distance correction of 20/40 or better was achieved by 29 of 43 eyes (67.4%). These data were compared retrospectively with data from control patients who received monofocal lenses, and no significant differences in the decreased number of corneal endothelial cells were found. Mean contrast sensitivities were within normal range for all spatial frequencies. Percentage of glare disability and near binocular vision were within normal limits. CONCLUSIONS: Eyes implanted with the five-zone refractive multifocal lens showed better near visual acuity than control eyes and compared favorably in other aspects of visual function, indicating that these lenses are effective and safe.

Contrast visual acuities in cataract patients. III. Changes of contrast acuity profiles in normal and pathological eyes.

We compared pre- and postoperative visual acuities in 45 cataract patients without ocular pathology except lens opacity (group 1) and 20 patients with ocular pathologies and lens opacity (group 2) using Variable Contrast Visual Acuity Charts. Charts 1 and 4 have 90% contrast; chart 4 has white optotypes on a black background (reverse polarity), charts 2 and 3 have 15% and 2.5% contrast, respectively. The mean preoperative visual acuities of groups 1 and 2 measured with the high-contrast Landolt optotypes ranged from 0.02-0.80 and 0.22-0.40, respectively. Visual acuity improvements between the pre- and postoperative periods ranged from 1.37-1.61 and 0.52-1.24 octaves in groups 1 and 2, respectively, with the different charts. Visual acuity improvement was poorest with chart 3. The group 1 mean preoperative visual acuity measured with chart 2 was 1.11 octaves lower than with chart 1. In group 2, the visual acuity reduction was 1.81 octaves. The relation between the visual acuities measured with the high-contrast intermediate-contrast optotypes are important for predicting postoperative visual acuity improvement. An abnormal contrast acuity profile may indicate the presence of additional ocular pathologies.

A ring to support the capsular bag after continuous curvilinear capsulorhexis.

We designed four prototypes of a capsular bag supporting ring for supporting and preserving postoperative integrity of the capsular bag, independently of the intraocular lens (IOL) implanted following continuous curvilinear capsulorhexis. An open poly(methyl methacrylate) ring, inserted experimentally in cadaver eyes through a 3.5 mm incision, adjusted well to various capsular bag sizes and could be implanted with common IOL types. Although some capsular shrinkage occurred in vitro, the roundness of the capsular bag equator was preserved, suggesting that the ring may help maintain postoperative capsular bag integrity.