Expert consensus on the identification, diagnosis, and treatment of neurotrophic keratopathy.

BACKGROUND: Neurotrophic keratopathy (NK) is a relatively uncommon, underdiagnosed degenerative corneal disease that is caused by damage to the ophthalmic branch of the trigeminal nerve by conditions such as herpes simplex or zoster keratitis, intracranial space-occupying lesions, diabetes, or neurosurgical procedures. Over time, epithelial breakdown, corneal ulceration, corneal melting (thinning), perforation, and loss of vision may occur. The best opportunity to reverse ocular surface damage is in the earliest stage of NK. However, patients typically experience few symptoms and diagnosis is often delayed. Increased awareness of the causes of NK, consensus on when and how to screen for NK, and recommendations for how to treat NK are needed. METHODS: An 11-member expert panel used a validated methodology (a RAND/UCLA modified Delphi panel) to develop consensus on when to screen for and how best to diagnose and treat NK. Clinicians reviewed literature on the diagnosis and management of NK then rated a detailed set of 735 scenarios. In 646 scenarios, panelists rated whether a test of corneal sensitivity was warranted; in 20 scenarios, they considered the adequacy of specific tests and examinations to diagnose and stage NK; and in 69 scenarios, they rated the appropriateness of treatments for NK. Panelist ratings were used to develop clinical recommendations. RESULTS: There was agreement on 94% of scenarios. Based on this consensus, we present distinct circumstances when we strongly recommend or may consider a test for corneal sensitivity. We also present recommendations on the diagnostic tests to be performed in patients in whom NK is suspected and treatment options for NK. CONCLUSIONS: These expert recommendations should be validated with clinical data. The recommendations represent the consensus of experts, are informed by published literature and experience, and may improve outcomes by helping improve diagnosis and treatment of patients with NK.

Phentolamine Eye Drops Reverse Pharmacologically Induced Mydriasis in a Randomized Phase 2b Trial.

SIGNIFICANCE: After a dilated eye examination, many patients experience symptoms of prolonged light sensitivity, blurred vision, and cycloplegia associated with pharmacological mydriasis. Phentolamine mesylate ophthalmic solution (PMOS) may expedite the reversal of mydriasis in patients, potentially facilitating return to functional vision and reducing barriers to obtaining dilated eye examinations. PURPOSE: The protracted reversal time after pharmacologically induced pupil dilation impairs vision. We tested the hypothesis that PMOS rapidly reduces pupil diameter in this acute indication. METHODS: In this double-masked placebo-controlled, randomized, two-arm crossover phase 2b trial, we evaluated the effects of one drop of 1% PMOS applied bilaterally in subjects who had their pupils dilated by one of two common mydriatic agents: 2.5% phenylephrine or 1% tropicamide. End points included change in pupil diameter, percent of subjects returning to baseline pupil diameter, and accommodative function at multiple time points. RESULTS: Thirty-one subjects completed the study (15 dilated with phenylephrine and 16 with tropicamide). Change in pupil diameter from baseline at 2 hours after maximal dilation with 1% PMOS was -1.69 mm and was significantly greater in magnitude compared with placebo for every time point beyond 30 minutes (P < .05). At 2 hours, a greater percentage of study eyes given 1% PMOS returned to baseline pupil diameter compared with placebo (29 vs. 13%, P = .03), which was this also seen at 4 hours (P < .001). More subjects treated with PMOS in the tropicamide subgroup had at least one eye returning to baseline accommodative amplitude at 2 hours (63 vs. 38%, P = .01). There were no severe adverse events, with only mild to moderate conjunctival hyperemia that resolved in most patients by 6 hours. CONCLUSIONS: Phentolamine mesylate ophthalmic solution at 1% reversed medically induced pupil dilation more rapidly than placebo treatment regardless of which mydriatic was used (adrenergic agonists and cholinergic blockers) with a tolerable safety profile.

Benefits and barriers of accommodating intraocular lenses.

PURPOSE OF REVIEW: Presbyopia and cataract development are changes that ubiquitously affect the aging population. Considerable effort has been made in the development of intraocular lenses (IOLs) that allow correction of presbyopia postoperatively. The purpose of this review is to examine the benefits and barriers of accommodating IOLs, with a focus on emerging technologies. RECENT FINDINGS: True accommodation of an IOL involves a dynamic increase in dioptric power to affect a shift from distance to intermediate or near focus. The Crystalens (Crystalens Bausch and Lomb, Inc., Rochester, NY, USA) was the first IOL labeled by the FDA as an accommodating IOL. Further studies have suggested that the Crystalens and several other single optic presbyopia-correcting IOLs may be providing improved intermediate or near vision predominantly through pseudoaccommodative mechanisms, in addition to small changes in axial translation. In light of these findings, a more objective demonstration of accommodation is now required for an IOL to have an accommodative label. Newer technology accommodating IOLs in development have embraced design strategies using dual optics, shape-changing optics, and IOLs with dynamic changes in refractive index. Prevention and treatment algorithms for capsular contraction syndromes unique to Crystalens and Trulign IOL designs will be discussed. SUMMARY: Accommodating IOLs that are in current use are constrained by their low and varied amplitude of accommodation. Such limitations may be circumvented in the future by accommodative design strategies that rely more on shape-related changes in the surfaces of the IOLs or in dynamic changes in refractive index than by forward translation alone.

Corneal inlays for presbyopia correction.

PURPOSE OF REVIEW: This study provides an overview of the three types of corneal inlays now in use for the correction of presbyopia and reviews recently published evidence of the inlays' safety and efficacy. RECENT FINDINGS: Results for corneal reshaping and refractive inlays are promising, but very limited. Small-aperture inlays are already in widespread use and have been shown to improve uncorrected near and intermediate vision without a significant loss in distance acuity or an unacceptable increase in visual symptoms. Complications have been minimal, but the inlays may be removed if necessary. They do not prevent visualization or imaging of the retina and may be retained during subsequent cataract surgery. SUMMARY: The presbyopic demographic is large and growing, with a high level of interest in spectacle independence. There is currently no other effective solutions for presbyopes who desire good uncorrected vision at all distances without the risks of intraocular surgery or the visual compromises of monovision. Additional research is needed, but the future for corneal inlay technology is bright.

Phentolamine Mesylate Ophthalmic Solution Provides Lasting Pupil Modulation and Improves Near Visual Acuity in Presbyopic Glaucoma Patients in a Randomized Phase 2b Clinical Trial.

PURPOSE: Phentolamine mesylate ophthalmic solution (PMOS), applied to the eye topically, was shown previously to have beneficial effects in patients with dim light vision disturbances (DLD), including decreased pupil diameter (PD), improved best-corrected distance visual acuity (BCDVA), as well as lower intraocular pressure (IOP). The ORION-1 trial evaluated the long-term safety and efficacy of PMOS in a glaucomatous, presbyopic population. PATIENTS AND METHODS: In this randomized, double-masked, multi-center, placebo-controlled, multiple-dose Phase 2b trial, 39 patients with elevated IOP were randomized to receive one evening dose of study medication or placebo for 14 days. The primary outcome measure was mean change in diurnal IOP, and the key secondary outcome measures included changes in PD, distance-corrected near visual acuity (DCNVA), and conjunctival hyperemia. RESULTS: Use of 1% PMOS did not lead to a statistically significant decrease in diurnal IOP compared to placebo (P = 0.89) but trended toward a greater decrease in patients with lower IOP baselines. PMOS produced a statistically significant mean 20% PD reduction under both photopic and mesopic conditions that was sustained for 36 hours post-dosing. A statistically significant number of patients with PMOS compared to placebo demonstrated ≥1 line of improvement in photopic DCNVA at day 8 (P = 0.0018), day 15 (P = 0.0072), and day 16 (P = 0.0163), with a trend for 2- and 3-line improvements at all time points. There was no statistical difference in conjunctival hyperemia compared to placebo. CONCLUSION: Although mean IOP was not lowered significantly, daily evening dosing of 1% PMOS was found to be well tolerated with no daytime conjunctival redness and demonstrated improvement in DCNVA with sustained PD reduction in a glaucomatous and presbyopic population. Smaller pupil size can have beneficial effects in improving symptoms of presbyopia and DLD, which will be the focus of further studies.

Perspective on Systematic Medical Literature Reviews and Meta-Analyses.

PURPOSE: This study sought to identify factors contributing to the inadequacies of systematic reviews and meta-analyses (SRMAs) published in the ophthalmology literature. DESIGN: Perspective. METHODS: Review and synthesis of selective literature, with interpretation and perspective. RESULTS: Although recommendations for the design, conduct, assessment of quality, and risk of bias of systematic reviews have been widely available, some recent publications illustrate a serious potential failing in this domain: inclusion of refuted science, lack of citation of post-publication correspondence and failure to use ≥1 alternative search strategy. CONCLUSIONS: Examples of inadequacies of peer review in medical literature and perpetuation of erroneous science by unfiltered inclusion in subsequent systematic reviews have been identified, and the problem can be traced to authors, peer reviewers, and editors of journals. This perspective identifies and analyzes several possible causes of the problem and recommends some specific corrective actions to improve the quality and accuracy of such reviews.

Direct and Indirect Costs of Infectious Conjunctivitis in a Commercially Insured Population in the United States.

PURPOSE: To assess the direct and indirect costs of infectious conjunctivitis and quantify medical costs due to conjunctivitis transmission in families. METHODS: In this retrospective claims analysis from the OptumHealth Care Solutions, Inc. database (1998-2016), beneficiaries with or without at least one diagnosis of infectious conjunctivitis were identified. Direct and indirect costs (in 2016 US$) during the 60 days post conjunctivitis diagnosis (or imputed date for controls) were compared using cost differences in linear regressions. For transmission cost analysis, the total cost of each conjunctivitis episode was the sum of the primary episode (seed patient) and the secondary episode (infected family members) costs. A generalized estimating equation model adjusted for seed patient characteristics was used to assess the impact of number and rate of transmissions on episode cost. RESULTS: Health care resource utilization and direct costs were significantly higher for patients with conjunctivitis (n=1,002,188) versus controls (n=4,877,210): 1.67 all-cause visits per person per month (PPPM) versus 0.79 visits PPPM, respectively; total mean direct cost of $396.04 PPPM versus $289.63 PPPM, respectively. The cost of medically related absenteeism was $105.42 (95% confidence interval [CI], $104.18-$106.75) higher for patients with conjunctivitis than for controls. Episode cost, without transmission due to seed patient, was $669.43 (95% CI, $654.67-$684.85); it increased with each additional infected family member and with increased infection transmission time between family members. CONCLUSION: Conjunctivitis was associated with a notable economic burden in terms of direct medical costs and medically related absenteeism. Family health care costs increased with transmission time and with each family member infected with conjunctivitis.

Objective Quantification of Image Quality and Optical Scatter Before and After Nd:YAG Capsulotomy Using a Double-Pass Technique.

PURPOSE: The purpose of this study is to evaluate and compare the correlation between changes in vision and HD Analyzer dual-pass metrics versus changes in vision and conventional subjective slit lamp gradings in pseudophakic patients with posterior capsular opacity undergoing neodymium:yttrium-aluminum-garnet (Nd:YAG) capsulotomy. PATIENTS AND METHODS: High contrast (HC) and low contrast (LC) best spectacle-corrected distance visual acuity (BCVA) and HD Analyzer evaluation were prospectively performed on patients with mild-to-moderate posterior capsular opacification (PCO) and monofocal and accommodating intraocular lens implants. Differences between pre- and post-operative measurements were calculated, along with the correlation of HD Analyzer metrics and slit lamp grading to changes in visual acuity. RESULTS: Following Nd:YAG capsulotomy (n=29), there was statistically significant improvement in HC-BCVA and LC-BCVA, decrease in optical scatter, and corresponding improvement in Strehl ratio and HD Analyzer values at all contrast levels tested (p≤0.05). Pearson test showed a high correlation between the improvement in HC-BCVA (r coefficient = 0.78) and LC-BCVA (r coefficient = 0.71) to the improvement in Objective Scatter Index (OSI). There was a higher correlation of change in HC-BCVA to pre-op OSI  (r2=0.61) than to the subjective PCO grading score (r2 = 0.19). There was also a higher correlation of change in LC-BCVA to pre-op OSI (r2 = 0.49) than to subjective grading (r2 = 0.16). CONCLUSION: The HD Analyzer provides objective measurements of forward light scatter (ie, light directed towards the retina) that can assist with both PCO grading and prediction of improvement of visual quality after YAG laser capsulotomy with higher accuracy than conventional slit lamp assessment based upon backscatter (ie, light traveling to the observer) in patients tested with monofocal and accommodating intraocular lens implants.

Comparison of contrast sensitivity, depth of field and ocular wavefront aberrations in eyes with an IOL with zero versus positive spherical aberration.

PURPOSE: To compare the clinical performance of the zero spherical aberration (SA) SofPort LI61AO (AO, Bausch & Lomb) intraocular lens (IOL) to the AcrySof SA60AT (AT, Alcon), which has positive spherical aberration. METHODS: Patients underwent uneventful phacoemulsification with implantation of either an aspheric (AO, n = 19) or spherical (AT, n = 20) IOL. Postoperatively, a 5 mm artificial pupil was positioned in trial frames with the cycloplegic refraction during monocular, mesopic contrast sensitivity (CSF) and low-contrast visual acuity (LCVA) testing with glare. Ocular and corneal wavefront error was determined at 5 mm diameters. RESULTS: Mean CSF scores were better at all frequencies tested for the AO than for the AT group, and achieved statistical significance at 1.5 cpd (p = 0.038) and 6 cpd (p = 0.017). With glare, AO eyes read 30.9 +/- 5.0 low-contrast letters versus 25.2 +/- 6.8 for AT eyes (p = 0.005) (mean DeltaLogMAR = -0.10), while high-contrast acuity and refraction were similar. Eyes implanted with the SA60AT had 43% greater positive spherical aberration at a 5 mm wavefront diameter, with no significant difference in corneal SA between groups. A through-focus analysis demonstrated a similar depth of field, yet a comparatively higher visual Strehl ratio for the aspheric IOL at emmetropia (p = 0.038). CONCLUSION: Eyes with the SofPort Advance Optics neutral aberration IOL demonstrated less spherical aberration and better low-contrast acuity compared to eyes with a spherical IOL, without sacrificing tolerance to defocus. The aspheric IOL showed superior optical and clinical performance, which is most likely due to its surface design.

A randomized controlled trial of povidone-iodine/dexamethasone ophthalmic suspension for acute viral conjunctivitis.

PURPOSE: To evaluate the clinical safety and efficacy of povidone-iodine (PVP-I) 0.6%/dexamethasone (DEX) 0.1% ophthalmic suspension vs vehicle in patients with clinically suspected acute viral conjunctivitis. PATIENTS AND METHODS: This was a randomized, double-masked, parallel-group, vehicle-controlled study. Adults with a clinical diagnosis of suspected acute viral conjunctivitis were randomized 1:1 to PVP-I/DEX ophthalmic suspension or vehicle bilaterally four times daily for 5 days (Days 1-5). Evaluation was on Days 1, 3 (+1-day window), and 6 (+1). Patients with signs of acute viral conjunctivitis at the Day 6 visit received open-label PVP-I/DEX for five additional days and were evaluated on Day 11-14. The primary efficacy endpoint was clinical resolution of acute viral conjunctivitis in the study eye at the Day 6 visit. RESULTS: Overall, 132 patients were randomized and received treatment (PVP-I/DEX, n=66; vehicle, n=66); 38 patients continued into the open-label portion of the study. Not enough patients with confirmed adenoviral conjunctivitis (n=32/132) were enrolled to assess the primary endpoint, although there were some efficacy trends in the PVP-I/DEX group for global clinical score (sum of watery conjunctival discharge and bulbar conjunctival redness). There were no serious treatment-emergent adverse events (TEAEs) and no patients discontinued due to a TEAE. In the masked phase, 56.1% of patients receiving PVP-I/DEX experienced at least one TEAE vs 43.9% in the vehicle group; 78.9% of patients in the open-label phase experienced at least one TEAE. Most TEAEs were mild in severity. CONCLUSION: PVP-I/DEX ophthalmic suspension administered for ≤14 days had a favorable safety profile and was generally well tolerated.

Longitudinal changes in dry eye symptoms and signs following lifitegrast therapy and relationship to tear osmolarity.

BACKGROUND: This study measured longitudinal changes in dry eye disease (DED) symptoms and signs following lifitegrast therapy and assessed their relationship to tear osmolarity to test the hypothesis that a decline in tear osmolarity is a reliable leading indicator of subsequent improvement in DED symptoms and signs after initiating lifitegrast treatment. METHODS: This phase IV, prospective, single-arm, open-label, 12-week study enrolled subjects aged ≥18 years with eye dryness score ≥40 (0-100 VAS) and tear osmolarity ≥308 mOsm/L. Subjects were prescribed lifitegrast ophthalmic solution 5%, twice daily in each eye. DED symptoms were assessed via VAS at baseline and 2, 6, and 12 weeks. Signs included tear osmolarity, meibomian gland dysfunction, tear breakup time, and fluorescein corneal staining. In post-hoc analysis, subjects with ≥5 mOsm/L decrease in osmolarity over 12 weeks were Responders. RESULTS: Of 26 subjects in the intent-to-treat population, 23 were female; mean age was 67.4 years. Baseline mean±SD eye dryness was 68.7±16.5 and tear osmolarity was 317.8±8.5 mOsm/L. All seven symptoms (dryness, burning, foreign body sensation, pain, photophobia, itching, blurred vision) declined significantly (P<0.01) from baseline to 6 and 12 weeks. Signs did not change significantly. For 13 Responders, tear osmolarity decreased from baseline to 12 weeks (319.2±8.5 to 300.6±12.3 mOsm/L, P<0.001) and corneal staining trended toward improvement (1.1±0.9 to 0.6±0.7, P=0.136). Among Nonresponders, osmolarity increased from 316.4+8.7 to 329.6+13.9 (P<0.01) and corneal staining showed no change (1.3±0.8 to 1.0±0.7 at 12 weeks, P=0.293). CONCLUSIONS: Lifitegrast reduced DED symptoms among subjects with moderate-to-severe disease (severity defined by VAS for eye dryness). Potential reasons that may underlie the dichotomous effect of drug treatment on tear osmolarity are discussed.

ISOPT Clinical Hot Topic Panel Discussion on Cornea Anterior Segment Disease.

The cornea and its adnexa pose a unique situation of a tightly defined set of requirements for its function. This includes: transparency, perfect built to obtain appropriate refractive power, protective barrier from microbial invaders. Moreso, the cornea also endures extreme external physical conditions (temperature, high and low humidity, winds and alike). All these functions are maintained while preserving a constant state of homogenous wetting. Toward that end the cornea is equipped with an elaborated network of sensory neural network. While enabling the blinking reflex and maintaining the physiological steady state of wetting, this neural network also makes the cornea prone to the discomfort that with or without associated changes seen on medical examination. ISOPT Clinical 2018 discussion touched upon this hypercomplex situation, addressing the role of inflammation and its resulting discomfort in dry eye conditions. The discussion also engulfed the emerging neuropathic pain syndrome that is recently gaining more attention. Another related topic was the utilization of autologous serum tears and its ability to provide amelioration to desperate patients. Finally, the panel discussed the issue of treating corneal infection, including when and how to utilize steroids in the course of therapy. We assume the reader will find interest in this discussion that directly addresses issues seen day in and day out in our busy clinics.

Randomized, Controlled, Phase 2 Trial of Povidone-Iodine/Dexamethasone Ophthalmic Suspension for Treatment of Adenoviral Conjunctivitis.

PURPOSE: To evaluate the efficacy/safety of an ophthalmic suspension of povidone-iodine (PVP-I) 0.6% and dexamethasone 0.1% in patients with acute adenoviral conjunctivitis. DESIGN: Multicenter, randomized, vehicle-controlled, double-masked trial. METHODS: Adults with a positive Rapid Pathogen Screening Adeno-Detector Plus test were randomized 1:1:1 to PVP-I 0.6%/dexamethasone 0.1%, PVP-I 0.6%, or vehicle, bilaterally 4 times daily for 5 days (days 1-5). Patients were evaluated on days 3, 6, and 12 (+1-day window). Efficacy measures included clinical resolution and adenoviral eradication. RESULTS: Overall, 144 patients were included in the efficacy analysis (PVP-I/dexamethasone, n = 48; PVP-I, n = 50; vehicle, n = 46). The proportion of patients with clinical resolution (primary study eye with last observation carried forward [LOCF]) at the day 6 visit was higher with PVP-I/dexamethasone (31.3%) than with vehicle (10.9%; P = .0158) and PVP-I (18.0%; P = nonsignificant). The proportion with adenoviral eradication (primary study eye with LOCF) was higher with PVP-I/dexamethasone than with vehicle at the day 3 (35.4% vs 8.7%; P = .0019) and day 6 (79.2% vs 56.5%; P = .0186) visits and vs PVP-I (day 3 visit, 32.0%; day 6 visit, 62.0%; each P = nonsignificant). Treatment-emergent adverse events (AEs) occurred in 69.0% (vehicle), 62.7% (PVP-I), and 53.4% (PVP-I/dexamethasone) of patients in the safety dataset. Discontinuation owing to AEs occurred in 37 patients (vehicle, n = 16; PVP-I, n = 12; PVP-I/dexamethasone, n = 9). CONCLUSION: PVP-I/dexamethasone appeared safe and well tolerated, and significantly improved clinical resolution and adenoviral eradication in patients with acute adenoviral conjunctivitis.

Evaluation of the small-aperture intracorneal inlay: Three-year results from the cohort of the U.S. Food and Drug Administration clinical trial.

PURPOSE: To evaluate the safety and effectiveness of the Kamra small-aperture intracorneal inlay. SETTING: Centers in North America, Europe, Asia, and Australia. DESIGN: Prospective clinical trial. METHODS: Patients with emmetropic presbyopia had intracorneal implantation of the inlay in the nondominant eye. RESULTS: The study comprised 507 patients with emmetropic presbyopia who were aged 45 to 60 years old. The implanted eyes exhibited 3.5 diopters of defocus range above 20/40, with 363 (87.1%) of 417 patients and 391 (93.8%) of 417 patients having 20/40 or better monocular and binocular uncorrected near visual acuity (UNVA) at 36 months, respectively. Patients implanted via a femtosecond laser pocket procedure using a spot/line setting of 6 µm × 6 µm demonstrated further improved near vision, with 131 (90.3%) of 145 patients and 137 (94.5%) of 145 of patients having 20/40 or better monocular and binocular UNVA, respectively. Uncorrected distance visual acuity 20/25 or better was maintained in 135 (93.1%) of 145 of implanted eyes and 100% (145) of 145 of implanted eyes binocularly at 36 months. Less than 1.5% of eyes had a loss of 2 or more lines of corrected distance visual acuity for 3 months or more at any time after surgery. Forty-four inlays (8.7%) were removed from the full cohort over 3 years. The removal rate was significantly less in the 6 × 6 pocket group (3.0% for visual complaints) and further reduced with deeper implantation (0%). Less than 1.0% of the patients reported severe glare or halos postoperatively. CONCLUSION: The small-aperture corneal inlay was found to be safe and effective, improving near vision both monocularly and binocularly with minimal effect on distance visual acuity.

A novel mutation of the Keratin 12 gene responsible for a severe phenotype of Meesmann's corneal dystrophy.

PURPOSE: To determine if a mutation within the coding region of the keratin 12 gene (KRT12) is responsible for a severe form of Meesmann's corneal dystrophy. METHODS: A family with clinically identified Meesmann's corneal dystrophy was recruited and studied. Electron microscopy was performed on scrapings of corneal epithelial cells from the proband. Mutations in the KRT12 gene were sought using direct genomic sequencing of leukocyte DNA from two affected and two unaffected family members. Subsequently, the observed mutation was screened in all available family members using polymerase chain reaction and direct sequencing. RESULTS: A heterozygous missense mutation (Arg430Pro) was found in exon 6 of KRT12 in all 14 affected individuals studied. Unaffected family members and 100 normal controls were negative for this mutation. CONCLUSIONS: We have identified a novel mutation in the KRT12 gene that is associated with a symptomatic phenotype of Meesmann's corneal dystrophy. This mutation results in a substitution of proline for arginine in the helix termination motif that may disrupt the normal helix, leading to a dramatic structural change of the keratin 12 protein.

Changes in corneal biomechanics and intraocular pressure following LASIK using static, dynamic, and noncontact tonometry.

PURPOSE: To compare the preoperative and postoperative measurement of corneal biomechanical properties and intraocular pressure (IOP) using Goldmann applanation tonometry (GAT), the ocular response analyzer (ORA), and the Pascal dynamic contour tonometer (PDCT) in eyes undergoing myopic laser in situ keratomileusis (LASIK). DESIGN: Prospective, nonrandomized clinical trial. METHODS: IOP was measured in 66 myopic eyes before and after LASIK by GAT, ORA, and PDCT in a randomized sequence. Metrics of corneal biomechanical properties (corneal hysteresis [CH], corneal resistance factor [CRF], and ocular pulse amplitude [OPA]) were recorded. RESULTS: After LASIK, there was a reduction in mean corneal pachymetry of 90.2 mum and in IOP measurements with GAT (Delta = -1.8 +/- 2.8 mm Hg; P < .01), ORA-Goldmann (Delta = -4.6 +/- 2.8 mm Hg, P < .01), and ORA-corneal compensated (Delta - 2.1 +/- 2.6 mm Hg; P < .05). However, there was no statistically significant difference between preoperative and postoperative IOP measurements taken by PDCT (Delta = -0.5 +/- 2.6 mm Hg). Postoperatively, CRF decreased by 28.6% (P < .01), CH by 16.2% (P < .01), and OPA by 1.8% (P = .32). CONCLUSIONS: Measurement of IOP with PDCT appears to be relatively immune to changes in corneal biomechanics and pachymetry after LASIK, in comparison to GAT and ORA measures of IOP. PDCT and ORA both showed statistically lower variation in measurement than GAT. LASIK produced a marked decline in CH and CRF, which may reflect respective changes in the viscous and elastic qualities of the post-LASIK cornea. In contrast, there was no statistical change in OPA.

Visual performance of patients with bilateral vs combination Crystalens, ReZoom, and ReSTOR intraocular lens implants.

PURPOSE: To compare the visual performance of patients with bilateral vs combination Crystalens, ReZoom, and ReSTOR intraocular lens (IOLs) implants. DESIGN: Prospective, nonrandomized study. METHODS: Forty-nine patients were implanted with bilateral Crystalens (Eyeonics, Aliso Viejo, California, USA), ReSTOR (Alcon Laboratories, Fort Worth, Texas, USA), and ReZoom (American Medical Optics, Santa Clara, California, USA) or combined Crystalens and ReSTOR or Crystalens and ReZoom IOLs after phacoemulsification. Monocular and binocular testing four to six months after surgery included uncorrected and best-spectacle corrected visual acuity at distance, intermediate, and near vision; mesopic contrast sensitivity function with and without glare; and quality-of-life and vision surveys six months after surgery. RESULTS: Monocular testing showed that eyes with Crystalens accommodating IOL had statistically better best-spectacle corrected distance, uncorrected and distance-corrected intermediate, and best-corrected near vision. Eyes with the ReSTOR multifocal IOL had better uncorrected near vision, required the lowest reading add, and had the lowest uncorrected and distance-corrected intermediate vision. Monocular mesopic contrast sensitivity with and without glare was better with the Crystalens IOL vs either multifocal IOL at specific spatial frequencies. The binocular subjective quality of vision and quality of life questionnaires were favorable for the bilateral Crystalens group. CONCLUSIONS: Any combination of Crystalens in one or both eyes was better for intermediate vision. Any combination of ReSTOR in one or both eyes was better for near vision. The Crystalens and ReSTOR combination had better mean intermediate and near vision overall. A multifocal IOL in one or both eyes was associated with lower contrast sensitivity and more subjective reports of photic phenomena. The accommodating and multifocal IOL combinations elicited less night glare symptoms than in patients with either bilateral multifocal IOL, but more than with bilateral Crystalens implantation.

Determining corneal power using Orbscan II videokeratography for intraocular lens calculation after excimer laser surgery for myopia.

PURPOSE: To assess the accuracy of Orbscan II slit-scanning videokeratography for intraocular lens (IOL) calculation in eyes with previous photorefractive surgery for myopia. SETTING: Private practice, St. Louis, Missouri, USA. METHODS: Corneal power (K) was measured by manual keratometry, Placido-based videokeratography (Atlas), slit-scanning videokeratography (Orbscan II), and contact lens overrefraction in 21 post-photoablation eyes having cataract surgery. Postoperative data collected after phacoemulsification were used to back-calculate corneal power (BCK). The BCK values were statistically compared at 3.0 to 6.0 mm central Orbscan II curvature and power measurements, including total axial power, total tangential power, total mean power, and total optical power. Similar comparisons were made to Atlas curvature at the 0.0 to 10.0 mm zones. RESULTS: The mean corneal power after refractive surgery based on BCK values using the Holladay 2 formula (BCK H2) was 39.35 diopters (D) +/- 2.58 (SD). The mean manual value (40.52 +/- 1.95 D) and Atlas-based values were statistically higher than BCK H2 values (P<.001). The mean corneal power calculated from historical data was 39.33 +/- 2.70 D (P = .83 to BCK H2; n = 19) and from contact lens overrefraction, 41.38 +/- 3.11 D (P = .19; n = 5). Orbscan II parameters (n = 21) of the total mean power (3.0 mm, 39.10 +/- 2.63 D), total tangential power (3.0 mm, 39.11 +/- 2.60), total axial power (5.0 mm, 39.19 +/- 2.55 D), and total optical power (3.0 mm, 39.08 +/- 2.78 D; 4.0 mm, 39.39 +/- 2.76 D) were statistically similar to both the historical and BCK H2 values (P>.11). If used prospectively, 80.9% of eyes would have been within +/-0.50 D of the targeted refraction using a 4.0 mm total optical power, 76.2% using a 5.0 mm total axial power, and 42.1% using the historical method. CONCLUSION: The Orbscan II 5.0 mm total axial power and 4.0 mm total optical power can be used to more accurately predict true corneal power than the history-based method and may be particularly useful when pre-LASIK data are unavailable.

Comparative performance of the Zyoptix XP and Hansatome zero-compression microkeratomes.

PURPOSE: To compare flap parameters produced by the Zyoptix XP and Hansatome microkeratomes (both Bausch & Lomb) and to evaluate preoperative variables contributing to flap thickness variation. SETTING: Private practice, St. Louis, Missouri, USA. METHODS: Flap dimensions in 75 eyes that prospectively had laser in situ keratomileusis using the Zyoptix XP microkeratome were compared with a historical control sample of 75 eyes treated with the Hansatome microkeratome. The 2 groups were matched for mean keratometry, central corneal pachymetry, spherical equivalent (SE), age, and microkeratome head size and suction ring diameter. RESULTS: The mean ultrasound-measured flap thickness was 126.54 microm +/- 14.6 (SD) and 143.74 +/- 15.0 microm for the 120 microm and 140 microm Zyoptix XP heads, respectively, and 128.90 +/- 20.4 microm and 143.32 +/- 21.0 microm for the 160 microm and 180 microm Hansatome heads, respectively. The standard deviation in flap thickness was smaller and statistically significant for the Zyoptix XP (+/-14.8 microm) versus the Hansatome (+/-20.7 microm) (P = .0039, F test). Preoperative pachymetry and SE (P<.001) accounted for 20% of the variability in measured flap thickness using the Hansatome. For the Zyoptix XP, preoperative pachymetry was statistically significant in explaining the variation in flap thickness with the 120 microm head (P = .02) but not with the 140 microm head. Variation in flap thickness from either Zyoptix XP head was not statistically related to the preoperative SE. CONCLUSION: Although the 2 microkeratomes produced flaps of similar mean thickness, the Zyoptix XP showed significantly less variation in flap thickness than the Hansatome, was less affected by measurable preoperative variables such as SE, and was closer to nominal labeling.

Accommodating Intraocular Lenses.

With an explosive increase in the worldwide prevalence of presbyopia, development of an accommodating intraocular lens (IOL) with expansive accommodative amplitude remains the holy grail in lens-based refractive surgery. A dynamic change in the dioptric power of the eye can be accomplished by various strategies alone or in combination, including changes in the position, shape, or refractive index of a single- or dual- optic IOL. This article reviews the cumulative advances in these various lens designs, along with clinical outcomes and complications of those that have been implanted. The challenges that remain in each cat-egory are also highlighted.