BMC Ophthalmology - Latest articles

Rotational stability of the AcrySof SA60TT toric intraocular lenses: a cohort study

Bruno Zuberbuhler, Theo Signer, Richard Gale and Eduard Haefliger — 2008-05-06

Background: To evaluate the rotational stability of the three types of AcrySof SA60TT toric intraocular lenses (Alcon, Switzerland) in cataract surgery after the first postoperative week. Methods: A retrospective study of 44 eyes in 33 patients. All patients underwent similar uncomplicated phacoemulsification cataract surgery. Seven eyes with corneal astigmatism of less than 1.5 D were implanted with the AcrySof SA60T3 intraocular lens. Seventeen eyes with astigmatism between 1.5 D and 2.25 D received the SA60T4 intraocular lens, and 20 eyes with more than 2.25 D of corneal astigmatism received the SA60T5 intraocular lens. Intraoperatively, the axis of the toric lens was aligned to the steepest axis of the corneal astigmatism. Main outcome measure was the postoperative position of the lens, assessed at 1 week and 3 months, using a specially designed angle measuring eyepiece for the slit lamp. Results: There was no significant difference in the rotational stability of the three types of toric intraocular lenses. Overall, the postoperative rotation was within 5 degrees in 95% and within 2 degrees in 68% of eyes. The mean absolute rotation was 2.2 +/- 2.2 degrees. No lens showed more than 9 degrees of rotation, and no lens required secondary repositioning. There was no trend for either clockwise or anti-clockwise rotation. The surgical procedure did not change the corneal astigmatism. Conclusions: Once placed to it's position, each of the three types of the AcrySof SA60TT toric intraocular lenses demonstrate rotational stability in the capsular bag.

Specific detection of fungal pathogens by 18S rRNA gene PCR in microbial keratitis

2008-04-29

Background: The sensitivity and specificity of 18S rRNA polymerase chain reaction (PCR) in the detection of fungal aetiology of microbial keratitis was determined in thirty patients with clinical diagnosis of microbial keratitis. Methods. Corneal scrapings from patients were used for Gram stain, culture and PCR analysis. PCR was performed with primer pairs targeted to the 18S rRNA gene. The result of the PCR was compared with conventional culture and Gram staining method. The PCR positive samples were identified by DNA sequencing of the internal transcribed spacer (ITS) region of the rRNA gene. Main outcome measures were sensitivity and specificity of PCR in the detection of fungus in corneal keratitis. Results. Combination of microscopy and culture gave a positive result in 11 of 30 samples of microbial keratitis. PCR detected 10 of 11 samples that were positive by conventional method. One of the 19 samples that was negative by conventional method was positive by PCR. Statistical analysis revealed that the PCR to have a sensitivity of 90.9% and specificity of 94.7% in the detection of a fungal aetiology in microbial keratitis. Conclusion. PCR is a rapid, sensitive and useful method to detect fungal aetiology in microbial keratitis.

A five-year retrospective study of the epidemiological characteristics and visual outcomes of patients hospitalized for ocular trauma in a Mediterranean area.

2008-04-22

Background: To determine the epidemiological characteristics and visual outcome of ocular trauma in southern Italy. Methods: All cases of ocular trauma admitted to Department of Ophthalmology of Palermo University, Italy, from January 2001-December 2005 were retrospectively reviewed for open- or closed-globe injury (OGI or CGI). Data extracted included age, sex, residence, initial and final visual acuity (VA), cause and treatment of injury, hospitalization. The injuries were classified by Ocular Trauma Classification System (OTCS) and Birmingham Eye Trauma Terminology (BETT). We also referred to the Ocular Trauma Score (OTS) in evaluating the final visual outcome. Results: Of the 298 eyes, there were 146 OGI and 152 CGI. Fifty eyes (16.8%) had an intraocular foreign body (IOFB). The annual incidence of eye injuries was 4.9 per 100,000. Most injuries occurred in men (84.6%, p<0.0005), with an average age of 33.0 vs. 49.9 for women (p=0.005). Cause of injury differed significantly by gender (p=0.001) and urban vs. rural location (p=0.009). The most frequent causes in men were outdoor activities related injuries (30.9%), work-related (25.4%), and sport-related (17.5%), and in women were home-related (52.2%) and outdoor activities related injuries (30.4%). In urban areas, road accidents were more frequent; in rural areas, work-related injuries were more frequent with a greater rate of IOFBs than in urban areas (p=0.002). The incidence of OGI and CGI differed in work-related injuries (p<0.0005), sport-related injuries (p<0.0005), and assaults (p=0.033). The final visual acuity was 20/40 (6/12) or better in 144 eyes (48.3%), 20/40-20/200 (6/12-6/60) in 90 eyes (30.2%), and <20/200 (6/60) or less in 46 eyes (15.5%). Eighteen eyes (6%) had a final acuity of no light perception. Of those eyes that presented with hand motion vision or better, 220 (86.6%) had a final vision of better than 20/200 (6/60). Initial visual acuity was found to be correlated with final visual acuity (Spearman's correlation coefficient=0.658; p<0.001). The likelihood of the final visual acuities in the OTS categories was correlated to that of the OTS study group in 12 of 14 cases (85.7%). Conclusions: This analysis provides insight into the epidemiology of patients hospitalized for ocular trauma. The findings indicate that ocular trauma is a significant cause of visual loss in this population.

Intravitreal vs. subtenon triamcinolone acetonide for the treatment of diabetic cystoid macular edema

2008-03-17

Background: To assess the efficacy of the intravitreal (IVT) injection of Triamcinolone Acetonide (TA) as compared to posterior subtenon (SBT) capsule injection for the treatment of cystoid diabetic macular edema. Methods: Fourteen patients with type II diabetes mellitus and on insulin treatment, presenting diffuse cystoid macular edema were recruited. Before TA injection all focal lakes were treated by laser photocoagulation. In the same patients one eye was assigned to 4 mg IVT injection of TA and the fellow eye was then treated with 40 mg SBT injection of TA. Before and one, three and six months after treatment we measured visual acuity with ETDRS chart as well as thickness of the macula with optical coherence tomography (OCT) and intraocular pressure (IOP). Results: The eyes treated with an IVT injection displayed significant improvement in visual acuity, both after one (0.491 ± 0.070; p < 0.001) and three months (0.500 ± 0.089; p < 0.001) of treatment. Significant improvement was displayed also in eyes treated with an SBT injection, again after one (0.455 ± 0.069; p < 0.001) and three months (0.427 ± 0.065; p < 0.001). The difference between an IVT injection (0.809 ± 0.083) and SBT injection (0.460 ± 0.072) becomes significant six months after the treatment (p < 0.001).Macular thickness of the eyes treated with IVT injection was significantly reduced both after one (222.7 ± 13.4 μm; p < 0.001) and after three months (228.1 ± 10.6 μm; p < 0.001) of treatment. The eyes treated with SBT injection displayed significant improvement after one (220.1 ± 15.1 μm; p < 0.001) and after three months (231.3 ± 10.9 μm; p < 0.001). The difference between the eyes treated with IVT injection (385.2 ± 11.3 μm) and those treated with SBT injection (235.4 ± 8.7 μm) becomes significant six months after the treatment (p < 0.001).Intraocular pressure of the eyes treated with IVT injection significantly increased after one month (17.7 ± 1.1 mm/Hg; p < 0.020), three (18.2 ± 1.2 mm/Hg; p < 0.003) and six month (18.1 ± 1.3 mm/Hg; p < 0.007) when compared to baseline value (16.1 ± 1.402 mm/Hg). In the SBT injection eyes we didn't display a significant increase of intraocular pressure after one (16.4 ± 1.2 mm/Hg; p < 0.450), three (16.3 ± 1.1 mm/Hg; p < 0.630) and six months (16.2 ± 1.1 mm/Hg; p < 0.720) when compared to baseline value (16.2 ± 1.3 mm/Hg). Conclusion: The parabulbar subtenon approach can be considered a valid alternative to the intravitreal injection.Trial registrationCurrent Controlled Trials ISRCTN67086909

Psychometric properties of the Greek version of the NEI-VFQ 25

2008-03-06

Background: To evaluate the reliability and construct validity of a Greek version of the NEI-VFQ-25 in patients with chronic ophthalmic diseases. Methods: We developed the Greek version of the instrument using forward and backward translation. One hundred-eighty-six patients responded to the questionnaire. To examine reliability, Cronbach's alpha for each subscale was used as an index of internal consistency. Test-retest reliability was evaluated with intraclass correlation coefficients. Regarding construct validity, both convergent and discriminant validities were calculated by means of multi-trait analysis. Rasch analysis was used to estimate the visual ability required by each item for a particular response, and each patient's visual ability. Correspondingly, instrument validity was evaluated by estimating the distribution of residuals for item and subject measures. Results: Four patient groups were studied, each including participants with a single cause of visual impairment. Group 1 consisted of 84 glaucoma subjects. Group 2 included 30 subjects with age-related macular degeneration (ARMD); group 3 included 25 subjects with dry-eye syndrome, whereas group 4 included 18 cataract patients. Twenty-nine healthy individuals comprised the control group. NEI-VFQ scores (mean ± SD) for the glaucoma, ARMD, dry-eye, cataract and control groups were: 76.9 ± 20.2, 70.9 ± 20.2, 81.6 ± 16.5, 73.5 ± 24.0 and 93.7 ± 8.9 respectively. Item analysis revealed no significant data skewing. Cronbach's alpha ranged from 0.678 to 0.926, with most subscales having high internal consistency. Intraclass correlation coefficient ranged from 0.717 to 0.910 for all subscales. All items passed the convergent and discriminant validity tests. Strong correlations were detected between visual acuity and "general vision", "distant activities" and "near activities" subscales. Significant correlations were also detected between visual field deficits and the "peripheral vision" and "general vision" subscales. Rasch analysis revealed potential weaknesses of the instrument that are associated with the assumptions of the model itself. Specifically, low precision of the "agreement" items was detected in the estimation of visual ability. Twenty-three percent of the subjects had fit statistics that fell outside the tolerance box. Conclusion: Although traditional validation methods indicated that the Greek version of the NEI-VFQ-25 is a valid and reliable instrument for VS-QoL assessment, Rasch analysis detected significant misfits to the model, especially of the "agreement" items. This means that results of the corresponding subscales should be interpreted with extreme caution.

Career choices for ophthalmology made by newly qualified doctors in the United Kingdom, 1974–2005

Trevor W Lambert, Michael J Goldacre and Anthony J Bron — 2008-03-04

Background: The paper aims to report trends in career choices for ophthalmology among UK medical graduates. Methods: Postal questionnaire surveys were undertaken of qualifiers from all UK medical schools in nine qualification years since 1974. Data were analysed by univariate cross-tabulation. The significance of comparisons between groups of doctors were calculated by the use of chi-squared tests and adjusted residuals. Results: Ophthalmology was the first choice of long term career for 2.3% of men and 1.5% of women one year after qualification; 2.0% of men and 1.4% of women three years after; and 1.8% of men and 1.2% of women at five years. Comparing early choices with eventual destinations, 64% who chose ophthalmology in year one, 84% in year three, and 92% in year five eventually practised in the specialty. The concordance between year one choice and eventual destination was higher for ophthalmology than for most other specialties. 'Enthusiasm for and commitment to the specialty' was the most important single factor in influencing career choice. The prospect of good working hours and conditions was also an important influence: it influenced career choice a great deal for a higher percentage of those who chose ophthalmology (66% in the third year) than those who made other surgical choices (23%). Conclusion: Those choosing ophthalmology show a high level of commitment to it. Their commitment is strengthened by the prospect of attractive hours and working conditions. Many doctors who become ophthalmologists have already made their choice by the end of their first post-qualification year.

Which quality of life score is best for glaucoma patients and why?

Philip Severn, Scott Fraser, Tracy Finch and Carl May — 2008-01-23

Background: The glaucomas are generally asymptomatic diseases until they are very advanced. They affect 2% of the population over 40 years of age and therefore represent a significant public health issue. There have been a number of attempts to develop quality of life scales for the disease. This review discusses the pros and cons of these scales and suggests the best of the current ones for use in a clinical setting. Methods: Medline, Embase and Google Scholar were searched for relevant articles. No time period was defined and all types of article were included. Results: 11 Quality of Life scores were identified that have been used with glaucoma patients. Conclusion: There is no generally accepted 'best' Quality of Life instrument for use in glaucoma. Many of the scales are biased towards physical symptoms and do little to address the personal or social factors of the disease. Further work is needed to produce scales that address all these areas as well as being simple to administer in a clinical setting.

The importance of central corneal thickness measurements and decision making in general ophthalmology clinics: a masked observational study

Ashish A Patwardhan, Mohammad Khan, Susan P Mollan and Paul Haigh — 2008-01-20

Background: To assess the impact of knowing central corneal thickness (CCT) on glaucoma management in a United Kingdom district general hospital. Methods: A masked observational non-interventional study included 304 eyes of 152 consecutive glaucoma cases attending general clinic. CCT was measured using a hand-held pachymeter. IOP, as measured by the Goldmann applanation tonometer (GAT), was adjusted for CCT using a normogram. Two identical study sheets were retrospectively constructed from each subject's case notes: one included the CCT and adjusted IOP information, the other excluded. Study sheets were randomly presented to a single masked observer to decide glaucoma management. The difference in management decision was noted. Results: The mean ± standard deviation CCT was 561.5 ± 35.7 μm, 538.9 ± 41.4 μm, 538.3 ± 40.3 μm for ocular hypertension (OHT), primary open angle glaucoma (POAG) and normal pressure glaucoma (NPG) subjects respectively. IOP adjustment was greater than ±2 mmHg in 33.9%(103/304) of eyes. CCT and adjusted IOP information led to different treatment option in 37%(55/152). Of the most important changes 20.4%(31/152) cases would have been commenced on additional IOP-lowering medication, 2.0%(3/152) would have been counselled for trabeculectomy surgery and 3.3%(5/152) of the cohort would have been observed rather than treated. Conclusion: CCT and adjusted IOP measurement can influence glaucoma management in a clinical context. It helps attribute risk and hence aids patient management decisions.

A decade of clinical negligence in ophthalmology

Nadeem Ali — 2007-12-20

Background: To present an overview of the clinical negligence claims for ophthalmology in the National Health Service (NHS) in England from 1995 to 2006. To compare ophthalmic subspecialties with respect to claim numbers and payments. Methods: All the claims on the NHS Litigation Authority database for ophthalmology for the period 1995 to 2006 were analysed. Claims were categorised by ophthalmic subspecialty, and subspecialties were ranked according to numbers of claims, total damages paid, average level of damages and paid:closed ratio (a measure of the likelihood of a claim resulting in payment of damages). Results: There were 848 claims, 651 of which were closed. 46% of closed claims resulted in payment of damages. The total cost of damages over the period was £11 million. The mean level of damages was £37,100. Cataract made up the largest share of claims (31%), paediatric ophthalmology had the highest mean damages (£170,000), and claims related to glaucoma were most likely to result in payment of damages (64%). Conclusion: Clinical negligence claims in ophthalmology in England are infrequent, but most ophthalmologists will face at least one in their career. Ophthalmic subspecialties show marked differences with regard to their litigation profiles. From a medical protection perspective, these results suggest that indemnity premiums should be tailored according to the subspecialty areas an ophthalmologist is involved in.

Age-related compaction of lens fibers affects the structure and optical properties of rabbit lenses

Samer Al-khudari, Sean T Donohue, Walid M Al-Ghoul and Kristin J Al-Ghoul — 2007-12-20

Background: The goal of this investigation was to correlate particular age-related structural changes (compaction) to the amount of scatter in rabbit lenses and to determine if significant fiber compaction occurred in the nuclear and inner cortical regions. Methods: New Zealand White rabbits at 16–20 months old (adult; n = 10) and at 3.5–4 years old (aged; n = 10) were utilized for this study. Immediately after euthanising, scatter was assessed in fresh lenses by low power helium-neon laser scan analysis. Scatter data was analyzed both for whole lenses and regionally, to facilitate correlation with morphometric data. After functional analysis, lenses were fixed and processed for scanning electron microcopy (SEM; right eyes) and light microscopy (LM; left eyes). Morphometric analysis of SEM images was utilized to evaluate compaction of nuclear fibers. Similarly, measurements from LM images were used to assess compaction of inner cortical fibers. Results: Scatter was significantly greater in aged lenses as compared to adult lenses in all regions analyzed, however the difference in the mean was slightly more pronounced in the inner cortical region. The anterior and posterior elliptical angles at 1 mm (inner fetal nucleus) were significantly decreased in aged vs. adult lenses (anterior, p = 0.040; posterior, p = 0.036). However, the average elliptical angles at 2.5 mm (outer fetal nucleus) were not significantly different in adult and aged lenses since all lenses examined had comparable angles to inner fetal fibers of aged lenses, i.e. they were all compacted. In cortical fibers, measures of average cross-sectional fiber area were significantly different at diameters of both 6 and 7 mm as a function of age (p = 0.011 and p = 0.005, respectively). Accordingly, the estimated fiber volume was significantly decreased in aged as compared to adult lenses at both 6 mm diameter (p = 0.016) and 7 mm diameter (p = 0.010). Conclusion: Morphometric data indicates that inner cortical fibers undergo a greater degree of age-related compaction than nuclear fibers. Increased scatter appears to be only tentatively correlated with regions of fiber compaction, suggesting that it is simply one of an array of factors that contribute to the overall decreased transparency in aged rabbit lenses.

Years of sunlight exposure and cataract: a case-control study in a Mediterranean population

2007-11-26

Background: We aimed to investigate the relation between sunlight exposure and risk of cataract. Methods: We carried out a frequency-matched case-control study of 343 cases and 334 controls attending an ophthalmology outpatient clinic at a primary health-care center in a small town near Valencia, Spain.All cases were diagnosed as having a cataract in at least one eye based on the Lens Opacification Classification system (LOCS II). Controls had no opacities in either eye. All cases and controls were interviewed for information on outdoor exposure, "usual" diet, history of severe episodes of diarrhea illness, life-style factors and medical and socio-demographic variables. Blood antioxidant vitamin levels were also analyzed. We used logistic regression models to estimate sex and age-adjusted odds ratios (ORs) by quintiles of years of occupational outdoor exposure, adjusting for potential confounders such as smoking, alcohol consumption, serum antioxidants and education. Results: No association was found between years of outdoor exposure and risk of cataract. However, exploratory analyses suggested a positive association between years of outdoor exposure at younger ages and risk of nuclear cataract later in life. Conclusion: Our study does not support an association with cataract and sunlight exposure over adult life.