Sue Ormonde

The New Zealand National Eye Bank study 1991-2003: a review of the source and management of corneal tissue.

Purpose: To evaluate donor demographics and source, donor tissue processing and storage, biologic contamination, and the utilization and distribution of corneal tissue procured by the New Zealand National Eye Bank. Methods: As part of a prospective longitudinal study, the electronic records of the NZNEB for the 13-year period 1991-2003 were analyzed for each year with respect to donor demographics, donor source and cause of death, death-to-preservation interval, storage methods, endothelial assessment, biologic contamination, corneal tissue utilization, and distribution. Results: During the study period, 3221 corneas were retrieved from 1628 donors (69.8% male, 30.2% female), with the mean age of donors 59.4 years (SD 18.3 years) and range 4 to 95 years. No significant correlation was identified between donor age group (using 10-year intervals) and the proportion of corneas suitable for transplantation. Donors were procured from the Coroners service (67.6%), public hospitals, (23.5%) and multiorgan donors (7.1%). The most common causes of donor death were cardiovascular disease, trauma, and cerebrovascular disease. Average storage duration increased from 3.5 to 11.8 days when organ culture replaced hypothermic storage in 1992. Biologic contamination occurred in 5% of all donor corneas. The most common bacterial and fungal isolates were coagulase-negative staphylococci and Candida spp, respectively. A significant decrease in contamination rate over the years of the study was identified. Overall, 79.4% of corneal tissue procured was used for corneal transplantation (75.8% for penetrating keratoplasty, 2.1% for lamellar keratoplasty, and 1.5% for unspecified transplants), and 21.6% was discarded. Most common reasons for discarding tissue were biologic contamination, abnormal serology, and failed endothelial assessment. Conclusion: Analysis of the NZNEB database provides valuable information in relation to eye banking and corneal transplantation in New Zealand. Significant trends were identified in donor demographics, donor procurement source, improved donor tissue processing and storage, decreased biologic contamination, and increased utilization of corneal tissue.

Higher-order aberrations of lenticular opacities.

Purpose: To measure and quantify higher‐order aberrations induced by different types of lenticular opacities. Setting: Department of Ophthalmology, University of Auckland, and Department of Ophthalmology, Auckland Public Hospital, Auckland, New Zealand. Methods: Patients with lenticular opacities were recruited from outpatient clinics of a major tertiary referral center for ophthalmology. Patients were included if they had clinically evident, mild to moderate lenticular opacity with no coexisting ocular pathology. Patients were examined using standard preoperative techniques with additional assessment by wavefront aberrometry (Zywave®, Bausch & Lomb) and Scheimpflug photography (EAS‐1000, Nidek). For comparison, 20 eyes of 10 subjects with no lenticular opacity (control group) were recruited and assessed in an identical manner. Results: Thirty persons were recruited and 40 eyes assessed, 20 with lenticular opacities. Ten eyes had predominantly cortical opacification, and 10 had mainly nuclear opacification. In eyes with predominantly cortical opacification, the mean logMAR uncorrected visual acuity (UCVA) was 0.5 ± 0.2 (SD) (6/18 Snellen equivalent) and the mean logMAR best spectacle‐corrected visual acuity (BSCVA), 0.2 ± 0.2 (6/9). Analysis of aberrometry data for a 6.0 mm pupil in this group revealed an increase in coma of cosine phase (Z31, P = .06) and tetrafoil of cosine phase (Z44, P = .07) compared to eyes in the control group. Eyes with predominantly nuclear opacification had a mean logMAR UCVA of 0.7 ± 0.2 (6/30) and a logMAR BSCVA of 0.4 ± 0.2 (6/15). Aberrometry data for this cohort for a 6.0 mm pupil showed a statistically greater amount of spherical aberration (Z40, P = .001) and tetrafoil of cosine phase (Z44, P = .005; Z4–4, P = .004). Conclusions: This pilot study suggests that different types of early lenticular opacities induce different wavefront aberration profiles. Predominantly cortical opacification produced an increase in coma and nuclear opacification induced an increase in spherical aberration compared to eyes without opacities. Both types of lenticular opacities also induced a higher amount of tetrafoil. This could explain the significant visual symptoms in patients with early cataract and relatively good high‐contrast Snellen acuity.

Acanthamoeba keratitis and contact lens wear

Acanthamoeba keratitis is a rare but serious complication of contact lens wear that may cause severe visual loss. The clinical picture is usually characterised by severe pain, sometimes disproportionate to the signs, with an early superficial keratitis that is often misdiagnosed as herpes simplex virus (HSV) keratitis. Advanced stages of the infection are usually characterised by central corneal epithelial loss and marked stromal opacification with subsequent loss of vision. In this paper, six cases of contact lens‐related Acanthamoeba keratitis that occurred in Australia and New Zealand over a three‐year period are described. Three of the patients were disposable soft lens wearers, two were hybrid lens wearers and one was a rigid gas permeable lens wearer. For all six cases, the risk factors for Acanthamoeba keratitis were contact lens wear with inappropriate or ineffective lens maintenance and exposure of the contact lenses to tap or other sources of water. All six patients responded well to medical therapy that involved topical use of appropriate therapeutic agents, most commonly polyhexamethylene biguanide and propamidine isethionate, although two of the patients also subsequently underwent deep lamellar keratoplasty due to residual corneal surface irregularity and stromal scarring. Despite the significant advances that have been made in the medical therapy of Acanthamoeba keratitis over the past 10 years, prevention remains the best treatment and patients who wear contact lenses must be thoroughly educated about the proper use and care of the lenses. In particular, exposure of the contact lenses to tap water or other sources of water should be avoided.

Connexin hemichannel induced vascular leak suggests a new paradigm for cancer therapy

It is 40 years since cancer growth was correlated with neovascularisation. Anti‐angiogenic drugs remain at the forefront of cancer investigations but progress has been disappointing and unexpected toxicities are emerging. Gap junction channels are implicated in lesion spread following injury, with channel blockers shown to improve healing; in particular preventing vascular disruption and/or restoring vascular integrity. Here we briefly review connexin roles in vascular leak and endothelial cell death that occurs following acute wounds and during chronic disease, and how connexin channel regulation has been used to ameliorate vascular disruption. We then review chronic inflammatory disorders and trauma in the eye, concluding that vascular disruption under these conditions mimics that seen in tumours, and can be prevented with connexin hemichannel modulation. We apply this knowledge to tumour vessel biology, proposing that contrary to current opinion, these data suggest a need to protect, maintain and/or restore cancer vasculature. This may lead to reduced tumour hypoxia, promote the survival of normal cells, and enable improved therapeutic delivery or more effective radiation therapy.

Refractive surgery for keratoconus.

Traditionally, keratoconus has been managed with glasses when mild, contact lenses when moderate and keratoplasty when severe. When cornea‐based refractive surgery was first developed it appeared to be a useful option for keratoconus until reports of post‐operative progressive ectasia emerged and thus keratoconus was considered a contraindication to refractive surgery. However, improvements in older techniques and the development of new techniques mean that there are now several viable options to avoid keratoplasty in contact lens‐intolerant patients. This review discusses the risks and benefits of excimer laser refractive procedures, both with and without corneal collagen cross linking, as well as intra‐corneal ring segments, phakic intraocular lenses and refractive lens exchange with toric intraocular lens implantation.Traditionally, keratoconus has been managed with glasses when mild, contact lenses when moderate and keratoplasty when severe. When cornea-based refractive surgery was first developed it appeared to be a useful option for keratoconus until reports of post-operative progressive ectasia emerged and thus keratoconus was considered a contraindication to refractive surgery. However, improvements in older techniques and the development of new techniques mean that there are now several viable options to avoid keratoplasty in contact lens-intolerant patients. This review discusses the risks and benefits of excimer laser refractive procedures, both with and without corneal collagen cross linking, as well as intra-corneal ring segments, phakic intraocular lenses and refractive lens exchange with toric intraocular lens implantation.

The New Zealand National Eye Bank: survival and visual outcome 1 year after penetrating keratoplasty

Purpose: To identify potential donor, recipient, surgical, and postoperative factors that may influence survival and visual outcome of penetrating keratoplasty (PKP). Methods: As part of a prospective longitudinal study, the electronic records of the New Zealand National Eye Bank were analyzed for the 10-year period from 1994-2003. Both univariate and multivariate analysis was performed. Results: During the study period, the New Zealand National Eye Bank supplied 1820 corneas for PKP and 1629 (90%) had 1-year follow-up data. Overall, the 1-year survival rate was 87% (n = 1429). Donor factors including age, donor source, cause of death, death-to-preservation interval, endothelial cell density, donor lens status, and storage duration, were not significantly associated with decreased survival. The leading cause of PKP failure was irreversible rejection (7%, n = 114). Independent risk factors identified for decreased PKP survival were: 1 or more episodes of reversible rejection, active inflammation at PKP, preexisting corneal vascularization, intraoperative complications, small graft size (≤7.25 mm), large graft size (≥8.5 mm), preoperative glaucoma, and a preoperative diagnosis of regraft or trauma. A best-corrected Snellen visual acuity of 6/12 or better was achieved in 60% of eyes [mean: 6/15 (logarithm of the minimum angle of resolution 0.40)]. Keratoconus and Fuchs endothelial dystrophy were the diagnoses with best survival and visual outcome, whereas, bullous keratopathy, trauma or noninfective keratitis were associated with poorer visual outcome. Conclusions: Several independent risk factors were identified that significantly influenced PKP first year survival outcome. This information is valuable to patients and surgeons with respect to determining prognosis and clinical decision making.

Publication and citation analysis of the Australian and New Zealand Journal of Ophthalmology and Clinical and Experimental Ophthalmology over a 10-year period: the evolution of an ophthalmology journal.

Purpose:  To analyse the pattern of change in publication content and citations generated by a mid‐ranking ophthalmology journal as it evolved from the Australian and New Zealand Journal of Ophthalmology (ANZJO) to its successor, Clinical and Experimental Ophthalmology (CEO).

In vivo confocal microstructural analysis and surgical management of brown-mclean syndrome associated with spontaneous crystalline lens luxation☆

We report 3 members of an extended family who presented with bilateral peripheral corneal edema consistent with Brown-McLean syndrome. On clinical examination, all eyes demonstrated normal central corneas and marked peripheral edema. In vivo confocal microscopy of the peripheral cornea highlighted similar observations in the 6 eyes including endothelial pigmentation, masked stromal structure due to edema, prominent nerves, and localized basal epithelial edema. In the central cornea, in vivo confocal microscopic observations highlighted large cellular structures with prominent nuclei in groups consisting of several cells of similar appearance. In vivo confocal microscopy may enhance the diagnosis of Brown-McLean syndrome and may be used for dynamic evaluation and postoperative follow-up of the structural corneal changes.

The plague that won't simply go away: acanthamoeba keratitis.

Acanthamoeba keratitis (AK), first described in 1974, is a relatively uncommon condition, but one which presents a substantial impact in terms of morbidity, visual loss and cost to health care services. There was a sharp upsurge in incidence in the 1980s as a result of the marked increased in the use of soft contact lenses and the use of home-made saline cleaning solutions. Fortunately, increasing knowledge and understanding of the condition and its risk factors, together with enhanced patient education regarding contact lens use, resulted in a significant reduction in acanthamoeba as a cause of severe infective keratitis by the mid 1990s. Rather disturbingly however, the incidence of AK appears to be undergoing an unwelcome renaissance over the last 4 years. This was initially highlighted by the University of Illinois, and investigated further by the Centers for Disease Control, establishing that there has indeed been a significant increase in AK across the USA from 2004. This trend has been confirmed in other studies, and in this issue Ku et al. have reported a rise in the incidence of AK in Brisbane, Australia, with a sixfold increase in 2006/7 compared with the preceding 3 years. The reasons for this increase are not entirely clear, but AMO Complete MoisturePlus multipurpose contact lens solution was strongly implicated as a key factor in the USA, although acknowledged to not be the only risk factor. This evidence resulted in a voluntary recall of the solution by the manufacturer. Other studies have also demonstrated that multipurpose cleaning solutions, which have become very popular with contact lens users owing to ease of use, are ineffective against acanthamoeba, and are associated with a rise in incidence of AK. Hydrogen peroxide cleaning systems are significantly more effective against acanthamoeba, but their use is more complicated and time-consuming, and they have fallen out of popularity with consumers. A further difficulty is that there are significant differences in the susceptibility of different acanthamoeba strains to disinfecting agents. Unfortunately, neither the US Food and Drug Administration or the International Organization for Standardization have hitherto required contact lens solutions to be tested for efficiency against acanthamoeba, partly because there are no standard testing regimens available, and partly because acanthamoeba was considered to be a very rare cause of keratitis. This problem is currently being addressed. Contact lenses themselves, and not just the solutions, are implicated too. Acanthamoeba demonstrates significantly greater affinity for first-generation silicone hydrogel lenses than for second-generation silicone hydrogel and conventional hydrogel lenses, and may promote greater risk of AK. Extended wear lenses are also becoming increasingly popular and these carry a significantly greater risk of all types of infective keratitis. Furthermore, there are new lens types to contend with, including coloured cosmetic contact lenses, which are usually purchased from the Internet or from the high street, with a consequent lack of optometric patient education and supervision regarding their use, and unsurprisingly they have already been reported to cause AK. Orthokeratology is another emerging modality, and this has also been associated with higher-than-expected incidence of AK. In this issue of Clinical and Experimental Ophthalmology, the study by Ku et al. similarly indicates that the type of contact lens solution and silicone hydrogel lenses combined with overnight wear were associated with the observed rise in incidence. The significant morbidity associated with AK and the risk of severe visual loss is well known. It has also been widely shown that earlier diagnosis and institution of appropriate anti-amoebic treatment is associated with better outcome. The need for urgent or elective penetrating keratoplasty is significantly more likely if diagnosis is delayed more than 3 weeks, and graft survival is generally poor, with the associated additional complications of glaucoma and recurrence of infection in the graft. Early diagnosis is often difficult, however, because of the fact that in the early stages of keratitis the signs can be rather non-specific and hence mimic other types of corneal infection, particularly herpes simplex keratitis. This is particularly the case if the ophthalmologist does not consider the diagnosis in non-contact lens wearers. Furthermore, definitive diagnosis with available diagnostic tests is difficult. Rates of positive culture from corneal scrapes and biopsies can be poor. PCR is emerging as a significantly more sensitive test, but is not readily available to all. Similarly, in vivo confocal microscopy (IVCM) has been demonstrated to be more sensitive and specific than culture, with the added benefit of being non-invasive, although like PCR it is not readily available to all. A combination of corneal scrapings and IVCM perhaps offers the highest likelihood of rapid accurate diagnosis. In order to make an early diagnosis therefore, it is beholden to the ophthalmologist to have a heightened awareness of the possibility of acanthamoeba in the diagnosis of atypical keratitis at the outset of the disease. This includes being aware of the risk factors and warning symptoms, as well as the myriad signs visible on slit-lamp Clinical and Experimental Ophthalmology 2009; 37: 155–157 doi: 10.1111/j.1442-9071.2009.02007.x

Endophthalmitis after contemporary cataract surgery: defining incidence and risk factors

Over the last 10 years small-incision phacoemulsification has become the preferred approach to cataract surgery in Australasia and the developed world. 1,2 In a recent representative, prospective study of 500 phacoemulsification procedures carried out in the New Zealand Public Health System the mean best-corrected visual acuity was 6/7.5 with a high level of patient satisfaction and a single case of acute endophthalmitis (0.2%). 3 It is against such a background of increasingly high standards of surgical and functional success that the unwelcome spectre of acute, visually disabling, endophthalmitis remains one of ophthalmologists’ greatest fears. Australian and New Zealand ophthalmologists have maintained extensive clinical and research interests in endophthalmitis and in this edition of the journal, Semmens et al. report a major study of endophthalmitis following cataract surgery in Western Australia between 1980 and 1998. 4