Influence of decentration and tilt of Tecnis ZCB00 on visual acuity and higher order aberrations.

BACKGROUND/OBJECTIVES: To determine the influence of decentration and tilt of a pseudophakic aspheric intraocular lens (IOL) on visual acuity (VA) and higher-order aberrations (HOAs), and to analyze the agreement between pupil center/axis and iridocorneal angles center/axis when assessing IOL decentration and tilt. SUBJECTS/METHODS: A prospective interventional case series study including thirty-three patients undergoing Tecnis ZCB00 (Abbott Medical Optics) implantation. IOL decentration and tilt with respect to two reference systems (pupil and iridocorneal angles centers/axes), in cartesian (X,Y) and polar (radius/tilt, polar angle/azimuth) coordinates, were assessed with optical coherence tomography. VA and internal and ocular HOAs were evaluated. Multiple linear regression models and intraclass correlation coefficient (ICC) were computed. RESULTS: IOL decentration only showed a significant effect on internal HOAs for [Formula: see text] (R2 = 0.20, P = 0.04). IOL decentration with respect to the pupil center showed a significant effect on ocular [Formula: see text] (R2 = 0.18, P = 0.05), [Formula: see text] (R2 = 0.36, P = 0.001) and [Formula: see text] (R2 = 0.24, P = 0.02); and with respect to the center of iridocorneal angles, on ocular [Formula: see text] (R2 = 0.21, P = 0.03), [Formula: see text] (R2 = 0.32, P = 0.003), primary coma (R2 = 0.41, P < 0.001), and coma-like (R2 = 0.40, P = 0.001). Poor agreement between both reference systems was found for IOL decentration measurements (ICC ≤ 0.41), except for the polar angle coordinate (ICC = 0.83). Tilt measurements showed good agreement (ICC ≥ 0.75). CONCLUSIONS: Tecnis ZCB00 decentration and tilt values after uneventful implantation appear not to have influence on VA, and their effect on HOAs are not high enough to clinically affect quality of vision. Pupil and iridocorneal angles used as reference systems may be interchangeable for IOL tilt measurements, but not for decentration.

Correction: Efficacy of toric intraocular lens implantation with high corneal astigmatism within the United Kingdom's National Health Service.

An amendment to this paper has been published and can be accessed via a link at the top of the paper.

Efficacy of toric intraocular lens implantation with high corneal astigmatism within the United Kingdom's National Health Service.

OBJECTIVES: To determine the efficacy of toric intraocular lens (TIOL) implantation in cataract surgery patients with high levels of pre-operative corneal astigmatism and ocular co-morbidities in a state funded, National Health Service (NHS) hospital. METHODS: Retrospective cohort study involving consecutive cases of TIOL implantation in cataract surgery with over 3.00DC of pre-operative corneal astigmatism. Subjects were implanted with the Tecnis TIOL (Abbot Medical Optics) with capsular tension ring stabilisation using the Callisto system (Carl Zeiss Meditec). Visual acuity and refraction were assessed at 4-6 weeks post-operatively. Vector analysis was used to calculate the intended refractive correction, surgically induced refractive correction (SIRC), correction ratio (CR), error of magnitude (EM) and error vector (EV). RESULTS: Sixty-six eyes of forty-seven subjects aged 73.8 ± 11.9 were included. Eyes with ocular co-morbidities included dry age-related macular degeneration (n = 13), amblyopia (n = 7), high myopia (n = 7), glaucoma (n = 6), previous corneal transplantation (n = 2), nanophthalmos (n = 2) and corneal scarring (n = 1). Pre-operative corneal astigmatism was 4.25 ± 1.69DC (range 3.00-12.00), post-operative refractive astigmatism was 1.31 ± 1.05DC (range 0.00-6.50DC) and post-operative unaided visual acuity was 0.25 ± 0.19 LogMAR. Vector analysis demonstrated an SIRC of 4.08 ± 1.39DC, CR = 1.1 ± 0.3, EM -0.4 ± 1.0 and EV of 1.23 ± 0.72. CONCLUSIONS: The results demonstrate the efficacy of TIOL implantation in patients with high corneal astigmatism and provide strong evidence advocating their use in cataract surgery within a state funded hospital eye service. Refractive astigmatism was significantly lower than the pre-operative corneal astigmatism and a low error vector was achieved relative to the magnitude of correction.

Intraoperative aberrometry-based aphakia refraction in patients with cataract: status and options.

AIM: To explore the application of intraoperative wavefront aberrometry (IWA) for aphakia-based biometry using three existing formulae derived from autorefractive retinoscopy and introducing new improved formulae. METHODS: In 74 patients undergoing cataract surgery, three repeated measurements of aphakic spherical equivalent (SE) were taken. All measurements were objectively graded for their quality and evaluated with the 'limits of agreement' approach. ORs were calculated and analysis of variance was applied. The intraocular lens (IOL) power that would have given the target refraction was back-calculated from manifest refraction at 3 months postoperatively. Regression analysis was performed to generate two aphakic SE-based formulae for predicting this IOL. The accuracy of the formulae was determined by comparing them to conventional biometry and published aphakia formulae. RESULTS: In 32 eyes, three consecutive aphakic measurements were successful. Objective parameters of IWA map quality significantly impacted measurement variability (p<0.05). The limits of agreement of repeated aphakic SE readings were +0.66 dioptre (D) and -0.69 D. Intraoperative biometry by our formula resulted in 25% and 53% of all cases ±0.50D and ±1.00 D within SE target, respectively. A second formula that took axial length (AL) into account resulted in improved ratios of 41% and 70%, respectively. CONCLUSIONS: A reliable application of IWA to calculate IOL power during routine cataract surgery may not be feasible given the high rate of measurement failures and the large variations of the readings. To enable reliable IOL calculation from IWA, measurement precision must be improved and aphakic IOL formulae need to be fine-tuned.

Comparison of reliability and repeatability of corneal curvature assessment with six keratometers.

BACKGROUND: Keratometric methodology varies between instruments and the differences may have a clinical impact. We investigated the agreement and reproducibility of six keratometers. METHODS: Keratometry was performed on 100 subjects at two separate sessions with IOLMaster 500, Pentacam, OPD scanner, Medmont E300, Javal-Schiøtz and TMS-5. A second observer assessed 30 subjects to determine inter-observer variability. A single individual was assessed on 10 separate sessions to determine intra-observer variability. Data were analysed using coefficient of variation (CV) and intra-class correlation coefficient (ICCC) for intra-observer variation. Inter-observer concordance was evaluated by the ICCC. Bland-Altman plots, Pearson's correlation coefficient and repeated measures analysis of variance were used to assess agreement of data produced by the instruments. RESULTS: OPD scanner and Javal-Schiøtz mean spherical equivalent (MSE) results were systematically different (p < 0.001) from other instruments (flatter and steeper, respectively). J0 /J45 were similar for all instruments (p < 0.05). Bland-Altman comparison plots indicated that Pentacam and IOLMaster demonstrated greatest level of agreement (ICC results MSE = 0.992, J0 = 0.934 and J45 = 0.890). Agreement (ICC) between observers for MSE ranged from 0.955 to 0.995 for all instruments; lower levels of agreement were found for J0 /J45 (0.289 to 0.901). IOLMaster showed greatest correlation and Medmont the lowest. All instruments showed high intra-observer repeatability of MSE (CV 0.1 to 0.3 per cent). The J0 /J45 readings showed greater variability (CV range 8.8 to 57.6 per cent). CONCLUSION: When considering MSE alone IOLMaster, Pentacam, OPD scan and Medmont may be considered interchangeable; however, assessment of astigmatism shows greater variability between instruments, sessions and observers.

Tectonic lamellar keratoplasty: simplified management of corneal perforations with an automated microkeratome.

OBJECTIVE: To describe a simplified tectonic lamellar keratoplasty (LK) technique, which can be used to manage full-thickness corneal perforations. DESIGN: Case series demonstrating a new surgical technique. PARTICIPANTS: A 69-year-old female with rosacea keratitis and peripheral corneal perforation; a 49-year-old male with keratoconus, ipsilateral herpes simplex keratitis and an inferonasal corneal perforation; and a 12-year-old female with an apparently spontaneous central corneal perforation. RESULTS: These 3 patients with full-thickness corneal perforations were successfully managed with this automated tectonic LK technique. CONCLUSIONS: Tectonic LK has benefits relative to tectonic penetrating keratoplasty but remains unpopular because it is technically difficult to prepare the host and donor corneas. This tectonic LK technique negates the need for challenging free-hand dissection and gives an excellent donor fit to the host bed. This provides an easier and more effective way to manage corneal perforations.

Intraocular lens opacification after corneal endothelial keratoplasty: electron microscopy and x-ray element spectroscopy analysis.

PURPOSE: To assess a newly recognized long-term complication of Descemet-stripping automated endothelial keratoplasty (DSAEK). SETTING: Plymouth Royal Eye Infirmary and Plymouth Electron Microscope Centre, Plymouth, United Kingdom. DESIGN: Retrospective case series. METHODS: This study evaluated cases of intraocular lens (IOL) opacification that developed after uneventful DSAEK. None of the IOLs was previously known to opacify. In 1 case, the opacified IOL was explanted and analyzed using detailed light microscopy, scanning electron microscopic (SEM) analysis, and element x-ray spectroscopy. RESULTS: In all 5 cases, the IOL was hydrophilic acrylic and the eye developed IOL anterior surface opacification 4 to 12 months after DSAEK. In 1 eye, the opacification was symptomatic; thus, an IOL exchange was performed. Light microscopy and SEM analysis of the explanted IOL confirmed opacification on the anterior surface and subsurface areas. X-ray element spectroscopy showed the granules were composed of calcium and phosphorous. CONCLUSIONS: These cases indicate that IOL opacification after DSAEK is a late, although newly recognized, complication of endothelial keratoplasty. FINANCIAL DISCLOSURE: No author has a financial or proprietary interest in any material or method mentioned.

Missed case of Axenfeld-Rieger syndrome: a case report.

BACKGROUND: Anterior segment dysgenesis is a failure of normal development of the anterior segment of the eye. The structural anomalies are associated with glaucoma and corneal opacity which may lead to blindness. CASE PRESENTATION: A Caucasian male was noted to have 'funny pupils' at the age of seven years but not followed up. He was diagnosed to have Axenfeld-Rieger syndrome at the age of thirty four years when he presented with glaucoma and visual field loss. CONCLUSION: Axenfeld-Rieger syndrome is uncommon. There is risk of sight loss due to glaucoma and corneal opacity. Importance of long-term follow up in cases of abnormal ocular findings in early life is emphasised.

Effect of midazolam on anxiety level and pain perception in cataract surgery with topical anesthesia.

PURPOSE: To study the effect of sedation on patients' anxiety level and perception of pain during cataract surgery under topical anesthesia. SETTING: Royal Eye Infirmary, Plymouth, England. METHODS: This prospective controlled double-blind clinical trial comprised 100 consecutive patients having routine phacoemulsification with posterior chamber intraocular lens implantation under topical anesthesia by a single experienced surgeon. Patients were randomized to receive intravenous midazolam (0.015 mg/kg body weight) 15 minutes before surgery or no sedation. The main evaluation criteria were the anxiety based on the 6-item, short form of the State-Trait Anxiety Inventory, the pain score using a visual analog scale, and overall patient satisfaction. RESULTS: All operations were uneventful, and no side effects were noted from the use of midazolam. Anxiety scores were significantly higher on arrival at the hospital than just before the commencement and after the conclusion of the surgery in both groups (P<.05). Patients were less anxious after administration of midazolam, but this did not achieve statistical significance. The mean pain score was 0.29 (range 0 to 4) in the sedation group and 0.38 (range 0 to 4) in the control group; the difference between groups was not statistically significant. The patients were equally satisfied in both groups, with mean scores of 3.84 (range 0 to 4) and 3.88 (range 2 to 4), respectively. CONCLUSIONS: Patients who had cataract surgery under topical anesthesia were highly satisfied with their operative experience and reported minimal pain during surgery. Anxiety levels diminished after arrival at the hospital, possibly because of reassurance by experienced staff. Intravenous midazolam did not seem to significantly reduce pain or anxiety.