What patients want to know before they have cataract surgery.

AIMS: To investigate what patients want to know before undergoing cataract surgery. METHODS: A written questionnaire was answered by 190 patients prior to cataract surgery. RESULTS: The five pieces of preoperative information rated most important were: chance of visual improvement; when vision would improve; overall risk of losing vision from the operation; effect of not having the operation, and the types of serious complications. When asked "should you be warned of a serious complication if it has a risk of happening", 93.5% said yes to a risk of 1 in 50 and 62.4% to 1 in 1000. Written information was requested by 85.7%. There were few differences between the sexes, and between those having their first or second operation. CONCLUSIONS: Patients most wanted to know benefits and risks, even very small risks. Written information should be provided to ensure coverage and reinforce verbal information.

A fast system for reporting the Farnsworth-Munsell 100-hue colour vision test.

We have developed a system for rapidly reporting the Farnsworth-Munsell (FM) 100-hue test using a personal computer and a bar code scanner. The computer generated report duplicates the conventional manual report of the FM 100-hue test so is very familiar to ophthalmologists and optometrists. The new system has proved to be of great assistance both in saving time and in eliminating arithmetic errors in the scoring calculations. The scanner technique produces two reports, one for each eye, within 4 min of the patient completing the test. This compares with the 60 min required by the conventional manual reporting system. In addition, it also gives a statistical analysis of the results in accordance with Verriest norms. The program is very versatile and user friendly, achieving a standard not present in the other FM 100-hue computerised systems currently available. As a consequence it makes this valuable diagnostic test much more accessible to patients and clinicians.

A comparison of two patient-friendly ERG electrodes.

The ideal electroretinography (ERG) electrode does not exist. In deciding which electrode should be used in clinical practice the capacity to provide reproducible waveforms, maximal amplitudes and minimal irritation to the patient's eyes are the most important characteristics. This study tested two patient friendly electrodes, the gold foil (CH Electrodes, UK) and the H-K loop (Avanta, Slovenia). Seventeen normal volunteers were subjected to three standard measurements namely flash ERGs under photopic and scotopic conditions and the transient pattern ERG (PERG). Each test followed the guidelines set by the International Society for Clinical Electrophysiology of Vision (ISCEV). It was found that the mean values of the flash ERG a and b wave amplitudes and the PERG P50 and N95 amplitudes from the gold foil electrodes were approximately a factor of two larger than those from the H-K loop. In addition most of the subjects (13/17) felt less discomfort with the gold foil electrodes. We reached the conclusion that gold foil electrodes are the electrode of choice because they provide good patient comfort, reasonably high amplitudes and relatively reproducible results.

Predicting the refractive outcome after cataract surgery: the comparison of different IOLs and SRK-II v SRK-T.

AIM: To determine any differences between the predictive abilities of the IOL calculation formulas of SRK-II and SRK-T and to compare these using two different IOL types. METHODS: A prospective, consecutive, single surgeon clinical trial was conducted on 400 consecutive patients who received routine, standardised phacoemulsification cataract surgery. 200 had cataract surgery and had the Alcon MZ30BD, a 5.5 mm one piece PMMA IOL, and another 200 cases used the Chiron C11UB, a silicone plate haptic IOL. The data used optimised A-constants. The measures were preoperative axial length and keratometry, IOL implanted, and refractive error at 4-6 weeks postoperatively. RESULTS: There was no significant difference between the predictive abilities of SRK-II or SRK-T. For the Alcon and Chiron lens respectively, prediction errors using SRK-II were <0.5 dioptres in 58% and 70% and for <1.0 dioptres in 84% and 92%. These differences were statistically significant (chi(2), p=0.02). CONCLUSION: There are differences in the predictability of refractive outcomes between intraocular lens styles.

Chiral Ansa metallocenes with Cp ring-fused to thiophenes and pyrroles: syntheses, crystal structures, and isotactic polypropylene catalysts.

Syntheses, crystal structures, and polymerization data for new isospecific metallocenes (heterocenes) having cyclopentenyl ligands b-fused to substituted thiophenes (Tp) and pyrroles (Pyr) are reported. The C2- and C1-symmetric heterocenes are dimethylsilyl bridged, have methyl groups adjacent to the bridgehead carbon atoms, and have aryl substituents protruding in the front. rac-Me2Si(2,5-Me2-3-Ph-6-Cp[b]Tp)2ZrCl2/MAO (MAO = methyl alumoxanes) is the most active metallocene catalyst for polypropylene reported to date. rac-Me2Si(2,5-Me2-3-Ph-6-Cp[b]Tp)2ZrCl2 and rac-Me2Si(2,5-Me2-1-Ph-4-Cp[b]Pyr)2ZrCl2 have the same structure, and the former is 6 times more active, produces half the total enantiofacial errors, and is 3.5 times less regiospecific in propylene polymerizations at the same conditions. rac-Me2Si(2-Me-4-Ph-1-Ind)2ZrCl2/MAO is 3.5 times lower in activity than rac-Me2Si(2,5-Me2-3-Ph-6-Cp[b]Tp)2ZrCl2 catalyst, and while the former is the more stereospecific and the less regiospecific, the sum of these two enantioface errors is the same for both species. Fine-tuning the heterocene sterics by changing selected hydrogen atoms on the ligands to methyl groups influenced their catalyst activities, stereospecificites, regiospecificites, and isotactic polypropylene (IPP) Mw. Thus, both substituting a hydrogen atom adjacent to the phenyl ring with a methyl group on an azapentalenyl ligand system and replacing one and then two hydrogens on the phenyl ring with methyls on thiopentalenyl ligands provided increased polymer Tm and Mw with increasing ligand bulk. Polymer molecular weights are sensitive to and inversely proportional to MAO concentration, and the catalyst activities increase when hydrogen is added for molecular weight control. The polymer Tm values with the thiopentalenyls as TIBAL/[Ph3C][B(C6F5)4] systems were higher than with MAO as catalyst activator. A racemic C1, pseudo-meso complex with a hybrid dimethylsilyl-bridged 2-Me-4-Ph-1-Ind/2,5-Me2-4-Ph-1-Cp[b]Pyr ligand produced the first sample of IPP with all the steric pentad intensities fitting the enantiomorphic site control model. Speculative mechanistic considerations are offered regarding electronic effects of the heteroatoms and steric effects of the ligand structures, the preferred phenyl torsion angles, and anion effects.

The early complications of cataract surgery: is routine review of patients 1 week after cataract extraction necessary?

OBJECTIVE: This study sought to define the nature and frequency of complications present 1 week after cataract surgery, to determine whether these complications are predictable, and to ascertain if patients undergoing cataract surgery require routine review at this time. DESIGN: Retrospective, noncomparative case series. PARTICIPANTS: One thousand consecutive patients undergoing cataract removal by either phacoemulsification or extracapsular extraction at a large teaching hospital between January 1996 and May 1998. Patients with both complicated and uncomplicated histories and surgeries were included. MAIN OUTCOME MEASURES: Nature and frequency of complications present 1 week after cataract surgery. RESULTS: At the routine 1-week visit, postoperative complications were observed in 41 of 1000 patients (4.1%). Twenty-one (51%) of these patients had a completely unremarkable history to that point, and whereas only four (19%) were symptomatic, 20 (95%) required a change to their postoperative management. The most significant unexpected complications were uveitis (seven cases), cystoid macular edema (four cases), and vitreous to the wound, exposed knots, and loose suture (one case of each). Complications were present in 20 of 257 (7.8%) patients with a preoperative or surgical risk factor, and there was a significant relationship between preoperative (P = 0.02), and combined preoperative and intraoperative risk factors (P = 0.001), and complications present at the 1-week review. The relationship between surgical risk factors and 1-week complications was not significant (P = 0.07). There were coexistent pathologic features in 19% of all eyes. Registrars performed 38% of surgeries, and 96% of cataracts were removed by phacoemulsification. Operative complications occurred in 6.7% of patients, most commonly a posterior capsule tear (4.4% of all cases). Complications were observed in 10% of eyes on the first postoperative day. Raised intraocular pressure was the complication in 88% of these patients. CONCLUSIONS: This study provides an overview of modern cataract surgery in a large teaching hospital and indicates that abandonment of routine 1-week review may result in the failure to detect significant postoperative complications.

Warfarin therapy and cataract surgery.

PURPOSE: Cataract extraction in the warfarinized patient poses special considerations. Warfarin will increase the haemorrhagic risk but, more importantly, cessation or reduction in anticoagulation may well lead to serious thromboembolic phenomena. The purpose of this study was to assess the impact that warfarinization has on cataract extraction. METHODS: One thousand consecutive cataract extractions performed at Christchurch Hospital between 1996 and 1998 were reviewed. Twenty-eight patients (29 eyes) were on warfarin. Reasons for anticoagulation, modification to treatment regimen and postoperative outcome measures were available for 23 eyes or 79% of the study population. RESULTS: The preoperative international normalized ratio (INR) ranged from 1.00 to 2.40+/-0.37 with a mean of 1.52. No thromboembolic phenomena occurred and four minor perioperative haemorrhages were noted, none of which affected the final visual outcome. CONCLUSIONS: If warfarin is required to counteract serious thromboembolic tendencies, then it should not be ceased perioperatively. The small numbers of perioperative haemorrhages that did occur were not visually significant.

Cyanoacrylate glue for corneal perforations: a description of a surgical technique and a review of the literature.

The effective early application of a cyanoacrylate glue corneal patch can aid in the management of small corneal perforations, corneal melts and wound leaks. Their use gives improved visual outcomes with reduced enucleation rates (6% vs 19%). It may also avoid the need for tectonic penetrating keratoplasty. Cyanoacrylate glue prevents re-epithelialization into the zone of damaged and naked stroma and prevents the development of the critical setting for collagenase production that leads to stromal melting. Cyanoacrylates also have significant bacteriostatic activity against gram-positive organisms. We describe a simple and easily reproducible method of cyanoacrylate corneal patch application, with neglible risk of inadvertent glue complications. It has the further advantage of a smooth corneal surface rather than an irregular surface as often occurs with direct application methods. With corneal application, the major concern is toxicity of cyanoacrylates through direct contact with the corneal endothelium and lens. Fibrin glues may be less toxic; however, they are not as readily available. The longer alkyl chains of currently available cyanoacrylate glues (e.g. Histoacryl) slows degradation significantly, limiting accumulation of histotoxic by-products to amounts that can be effectively eliminated by tissues. Vigilance in monitoring for infection/corneal infiltrate is necessary at all times, especially when the glue has been present for more than 6 weeks. Corneal patching with cyanoacrylate glue is a temporizing procedure only, buying time to allow healing secondary to medical treatment of the underlying condition, or allowing surgery to be elective and under more optimal conditions once inflammation has been reduced and the integrity of the globe restored.

Visual, refractive, and subjective outcomes after photorefractive keratectomy for myopia of 6 to 10 diopters using the Nidek laser.

PURPOSE: To analyze the results of photorefractive keratectomy (PRK) for myopia of 6.0 to 10.0 diopters (D) using the Nidek laser and compare them with those in other series, including LASIK, and to analyze the subjective aspects of vision. SETTING: Remuera Eye Clinic, Auckland, New Zealand. METHOD: One hundred ninety-two eyes of 162 consecutive PRK patients with a 6 month follow-up were studied. All had myopia in the range of 6.0 to 10.0 D by spherical equivalent. Astigmatism of up to 3.5 D was treated by laser simultaneously. At 6 months, uncorrected visual acuity, best spectacle-corrected visual acuity, residual refractive error, and corneal haze were recorded. After the 6 month examination, a questionnaire was sent to all patients. RESULTS: Uncorrected visual acuity of 20/20 was achieved in 59% of eyes and of 20/40 or better in 94%. The accuracy of correction was +/- 0.5 D of emmetropia in 77% and +/- 1.0 D in 94%. In 2 eyes (1.0%), corneal haze was assessed as 2+ and 2 Snellen lines of best corrected visual acuity were lost. The questionnaire revealed that 45% of patients had difficulties with night vision. This was better than before surgery in 35% but worse in 31%. Halos were seen around lights by 52%, but these were less than before surgery in 21% and worse in 26%. There was undue sensitivity to glare in 29%, but this was better than before surgery in 19% and worse in 28%. The overall quality of vision was better than before surgery in 60% and worse in 17%. Seventy-seven percent did not need spectacles. Ninety-eight percent said they would have the surgery again. CONCLUSIONS: As long as the patients are informed of the limitations of PRK for myopia, the results are acceptable.

Primary choroidal malignant melanoma occurring in a New Zealand Maori.

PURPOSE/METHOD: A case of a 28-year-old Maori with an aggressive primary choroidal malignant melanoma is presented. RESULTS/CONCLUSION: Melanoma and particularly intra-ocular melanoma is very rare in pigmented races. This is the first reported case in the Maori.

Intraocular lens materials and styles: a review.

Biomaterial science has lead to the development of a variety of foldable intraocular lens (IOL) biomaterials. This literature review examines these lenses from both a basic science and a clinical perspective. By most parameters, hydrogel, soft acrylic and silicone IOL are better than polymethylmethacrylate (PMMA) lenses. Plate haptic silicone IOL have the lowest incidence of cystoid macula oedema and posterior capsule opacification, but these lenses require an intact anterior capsularhexis and posterior capsule. Yttrium aluminium garnet (YAG) laser capsulotomy must be delayed at least 3 months to avoid posterior lens dislocation. Silicone has the lowest threshold for YAG laser damage of all IOL materials and also adheres irreversibly to silicone oil with subsequent optical impairment. Three piece silicone IOL with polypropylene haptics have a higher incidence of decentration, pigment adherence and capsule opacification compared with PMMA haptics. Hydrogel lenses are very biocompatible and resistant to YAG laser damage, but pigment adheres to the surface more readily than PMMA. Soft acrylic IOL unfold slowly, resulting in controlled insertion, but it is possible to crack the lens and some lenses develop glistenings due to water accumulation. There are significant socioeconomic implications to the large differences in posterior capsule opacification rates between the various biomaterials and the lens styles.

Conjunctival fibrosis in ocular cicatricial pemphigoid--the role of cytokines.

Ocular cicatricial pemphigoid (OCP) is a systemic, autoimmune disease characterised by conjunctival scarring that is often progressive. The pathophysiology of the fibrosis is unknown. This study aimed to determine which fibrogenic cytokines are present in the conjunctiva in patients with acute and chronic OCP as a first stage in determining the mechanisms of fibrosis. Conjunctival biopsies from patients with acute, subacute and chronic OCP (n=13) were compared to normal conjunctiva (n=10). Production of mRNA for, and expression of, transforming growth-beta1, 2 and 3 (TGF-beta), TGF-beta receptor, platelet derived growth factor (PDGF) and fibroblast growth factor (FGF) were assessed using in situ hybridisation and immunohistochemistry. Acute disease showed increased levels of mRNA for TGF-beta1 and 3, mainly in stromal fibroblasts and macrophages. In the stroma, there were concordant increases in latent and activated TGF-beta1 and 3 and TGF-beta receptor expression by fibroblasts. There were no significant increases in the expression of TGF-beta2, PDGF or FGF in acute disease. No cytokines or receptors were significantly increased in chronic disease. Acutely inflamed conjunctiva in OCP is associated with significant stromal levels of TGF-beta1 and 3 but not PDGF or FGF and none were increased in chronic disease. This suggests that TGF-beta may have a key role in the pathogenesis of the fibrosis. The absence of fibrogenic cytokines in chronic progressive OCP provides support for the proposal that fibroblasts in OCP conjunctiva may remain functionally and morphologically abnormal after the withdrawal of cytokine influences.

Acute ocular methanol toxicity: clinical and electrophysiological features.

PURPOSE: The present report describes previously undocumented changes in the electroretinogram (ERG) and visual-evoked response (VER) following acute methanol ingestion and highlights the ocular effects of methanol poisoning. METHODS: Two cases of acute ocular damage following methanol ingestion are presented. One patient underwent extensive electrophysiological and psychophysical testing. RESULTS: Both patients reported transient visual disturbances. In each patient vision was 6/6 in both eyes at presentation but subsequently improved to 6/4. Colour vision (Ishihara plates) and pupillary reactions were normal. The optic discs were hyperaemic and swollen and retinal oedema extended along the major vascular arcades. There was cystoid macular oedema and 'pseudo cherry red spots' were observed. Automated field analysis revealed a generalized depression of retinal sensitivity, an enlargement of one blind spot and paracentral scotomas. The scotopic ERG was subnormal with diminished a- and b-waveforms and the cone response to flicker was reduced. The pattern VER P2 waveform was normal in latency but decreased in amplitude. CONCLUSIONS: Acute methanol ingestion can cause characteristic ocular damage, together with widespread electrophysiological dysfunction. The data presented suggest that methanol affects the photoreceptors, Muller cells and the retrolaminar portion of the optic nerve.

A method for separation and staining of flat mounts of human corneal endothelium.

A technique is described in which sheets of corneal endothelium are removed from human donor corneo-scleral discs. Celloidin solution was applied to the endothelial surface, allowed to dry, peeled off with the attached endothelial cell layer and mounted on a glass slide. Following removal of the celloidin with acetone, this endothelial cell flat mount was then stained with H&E and monoclonal antibodies to cell adhesion molecules. A pilot study of endothelial cell adhesion molecule expression in flat mount preparations of 14 corneas showed constitutive neural cell adhesion molecule (NCAM) expression, but a lower degree of focal expression of intercellular adhesion molecule (ICAM)-1, vascular cell adhesion molecule (VACM)-1, P/E-selectin and HLA-DR.

Anatomy and physiology of eyelash follicles: relevance to lash ablation procedures.

BACKGROUND: This study aimed to define the anatomy of the eyelash follicles in order to improve methods of selective lash ablation. MATERIALS AND METHODS: Dimensions of eyelash follicles were determined from histological specimens of the upper and lower lids of 10 patients. For one of these patients, the eyelash follicles were categorized as quiescent or actively growing, according to standard hair-cycle morphology. RESULTS: Follicle dimensions were (mean +/- SD): upper lid follicle depth, 1.8 +/- 0.3 mm; bulb width, 188 +/- 44 microns; shaft width, 205 +/- 28 microns; lower lid follicle depth, 0.9 +/- 0.2 mm; bulb width 132 +/- 19 microns; and shaft width, 158 +/- 26 microns. The upper lid comprised 41% active follicles compared to 15% in the lower lid. CONCLUSIONS: There are significant differences in the anatomy of the follicles between the two lids. For an electrolysis needle to completely contact 95% of all follicles, it must be inserted 2.4 mm into the upper lid and 1.4 mm into the lower lid (mean depth +2 SD). Argon laser ablation requires a beam width of < 200 and < 250 microns for the lower and upper lids, respectively, to treated similar depths as electrolysis. The higher proportion of actively growing upper lid follicles explains why upper lid lashes are longer.