Mark J Elder

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.

Biofilm-related infections in ophthalmology

A biofilm is a functional consortium of microorganisms organised within an extensive exopolymer matrix. Organisms within a biofilm are difficult to eradicate by conventional antimicrobial therapy and can cause indolent infections. This paper reviews the pathophysiology of biofilms and their application of ophthalmology. Under certain environmental conditions such as nutrient limitation, some bacteria may secrete and reside in an exopolysaccharide glycocalyx polymer. This confers relative protection from humoral and cellular immunity, antibiotics and surfactants. Biofilms occur in natural aquatic ecosystems, on ship hulls, in pipelines and on the surface of biomaterials. They cause clinical infections of prosthetic hip joints, heart valves and catheters. Biofilm formation may occur rapidly on contact lenses and their cases and hence contribute to the pathogenesis of keratitis. Formation of biofilms is also implicated in delayed post-operative endophthalmitis and crystalline keratopathy. Bacteria within biofilms are 20-1000 times less sensitive to antibiotic than free-living planktonic organisms. Existing experimental methods for modifying biofilm include the use of macrolide antibiotics that specifically impair biofilm production, and the use of enzymes to digest it. These may have clinical applications, as potential adjunctive therapies to antibiotic treatment, for these resistant infections. In conclusion, biofilm is an important cause of infections associated with biomaterials. Novel strategies are needed to deal with these.

Leber Congenital Amaurosis and Its Association With Keratoconus and Keratoglobus

Leber congenital amaurosis has been associated with keratoconus and it has been postulated that this is due to eye rubbing, the oculo-digital sign, because of poor vision. Six schools for the blind were visited, and 174 children with a visual acuity of less than 3/60 examined. Thirty-five children had Leber amaurosis, and 10 of these had keratoconus (29%) and one had keratoglobus (3%). The six pedigrees of the cases with Leber amaurosis and keratoconus are presented in detail. Only 3 of the 139 other blind children had keratoconus (P < .05) and 1 had keratoglobus. Keratoconus seems specifically associated with Leber amaurosis, probably due to genetic factors, rather than poor visual acuity per se.

Progression of disease in ocular cicatricial pemphigoid.

BACKGROUND: Ocular cicatricial pemphigoid (OCP) is a sight threatening autoimmune disease that can lead to severe conjunctival cicatrisation and keratopathy. It has a variable course and little is known about the factors that determine disease progression. This study analysed the factors that have prognostic significance regarding disease outcome, progression, and keratopathy. METHODS: Sixty six patients with OCP were monitored prospectively at Moorfields Eye Hospital. The influence of ocular features, the systemic disease, and the management were analysed to identify factors that influence the outcomes and disease progression. RESULTS: The mean age at presentation was 67 years; 56% were men. The binocular visual acuities were 6/24 or worse in 25%. Extensive cicatrisation at presentation was common but correlated only weakly with the visual prognosis. Systemic manifestations included lesions of the mouth in 44%, pharynx in 30%, oesophagus in 27%, nose/sinus in 18%, and skin in 17%. There was no association between the ocular and systemic manifestations. Persistent corneal epithelial defects and limbitis occurred in 18% and 32%, respectively, and both were associated with a worse visual prognosis. Systemic immunosuppression was ultimately prescribed in 74%, mainly in patients with advanced stages of conjunctival cicatrisation. Of patients with more than 24 months follow up, progression of cicatrisation occurred in 35% of eyes (16/46) all but one of which were associated with episodes of conjunctival inflammation. CONCLUSIONS: Persistent epithelial defects, limbal inflammation, and ongoing conjunctival inflammation are important factors that lead to keratopathy and visual handicap. These require aggressive management, often with systemic immunosuppressive treatment. Close follow up is required in cases with extensive cicatrisation.

Apparent accommodation and depth of field in pseudophakia

Purpose: To assess depth of field in phakic and pseudophakic eyes to explain good distance and uncorrected near visual acuity in pseudophakic eyes. Setting: Department of Ophthalmology, University of Otago Medical School, Dunedin, New Zealand. Methods: Depth of field was measured in pseudophakic (n = 10) and phakic (n = 10) eyes for both near and distant targets. Test conditions included cycloplegia and a constant pupillary aperture using a soft contact lens with a central artificial pupil diameter of 2.5 mm. Results: There was no statistically significant difference between phakic and pseudophakic eyes for any test. Depth of field for near visual acuity was ±0.85 diopters (D), but amplitude of legibility was ±1.94 D. Depth of field for distance visual acuity was between 0.25 and 0.50 D in 85% of eyes. Conclusion: In the absence of astigmatism and disease, a pseudophakic eye with ‐0.75 D of myopia can expect to achieve 20/30 uncorrected distance acuity and read N5 unaided if the pupil is approximately 2.5 mm.

The New Zealand cataract and refractive surgery survey 2001

Background:  This study examines the current practice and trends for cataract and refractive surgery in New Zealand.

Medical treatment of cataract.

The incidence of cataract continues to increase with the ageing of the population. Surgical treatment with phacoemulsification and intraocular lens implantation remains the only proven treatment. This, however, is associated with significant cost and is not readily available especially in the developing countries where the prevalence of cataract is the highest. Medical treatment of cataract is therefore a highly desired alternative. Since the last major review of medical treatment of cataract the search for an anti‐cataract agent has advanced on many fronts. Some anti‐cataract drugs, such as carnosine, have now reached clinical trials and showed encouraging results that warrant further investigation. The discovery of an effective medical treatment for cataract is likely to make global impact on eye health. The aims of this paper are to review the literature on the drug therapy of cataract and provide updates of the latest development.

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.

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 (χ2, p=0.02). Conclusion: There are differences in the predictability of refractive outcomes between intraocular lens styles.

New Zealand experience of I125 brachytherapy for choroidal melanoma.

Purpose:  To examine patient survival, visual function and complications in all patients with choroidal melanoma treated with I125 brachytherapy between 1995 and 2003 at the authors’ institution. To compare the results from their institution with those from international series.