East London's Homeless: a retrospective review of an eye clinic for homeless people.

BACKGROUND: There is very little published work on the visual needs of homeless people. This paper is the first study to investigate the visual needs of homeless people in the UK. Although similar work has been done in other countries, this study is unique because the United Kingdom is the only country with a National Health Service which provides free healthcare at the point of access. This study analysed the refractive status of the sample used, determined the demographics of homeless people seeking eye care and established if there is a need for community eye health with access to free spectacle correction in East London. METHODS: This retrospective case study analysed the clinical records of 1,141 homeless people using the Vision Care for Homeless People services at one of their clinics in East London. All eye examinations were carried out by qualified optometrists and, where appropriate, spectacles were dispensed to patients. Data captured included age, gender, ethnicity and refractive error. Results were analysed using two-sample t-tests with Excel and Minitab. RESULTS: Demographics of age, gender and ethnicity are described. Spherical equivalents (SE) were calculated from prescription data available for 841 clinic users. Emmetropia was defined as SE-0.50DS to +1DS, myopia as SE < -0.50DS, and hyperopia as SE > +1DS. The majority of clinic users were male (79.2 %, n = 923). Approximately 80 % (n = 583) of clinic users were white, 10 % (n = 72) were 'black', 4 % (n = 29) 'Asian' and the remaining 5.6 % (n = 40) were of 'mixed ethnicity' and 'other' groups. The mean age of females attending the clinic was significantly lower than that of males (45.9 years, SD = 13.8 vs' 48.4 years, SD = 11.8) when analysed using a two-sample t-test (t (317) = 2.44, p = 0.02). One third of service users were aged between 50-59 years. Myopia and hyperopia prevalence rates were 37.0 % and 21.0 % respectively. A total of 34.8 % of homeless people were found to have uncorrected refractive error, and required spectacle correction. CONCLUSIONS: This study has identified a high proportion of uncorrected refractive error in this sample and therefore a need for regular eye examinations and provision of refractive correction for homeless people.

Keratoconus and granular dystrophy.

Concurrent bilateral keratoconus and granular dystrophy is reported in a 32-year-old patient with decreased vision. Initially contact lenses were attempted unsuccessfully to treat the conditions. There are a handful of other reports of these combined pathologies in the literature, and the likelihood of a chance cause or possible genetic linkage between the conditions is discussed.

Seeing you through London 2012: eye care at the Paralympics.

BACKGROUND: The provision of eye care services for competitors and support teams is integral to the modern Olympic Games. The eye clinic for the London 2012 Paralympic Games employed a multidisciplinary team of eye care professionals using state-of-the-art instrumentation to provide the highest level of eye care. The detailed organisation of the eye care clinic at London 2012 is described in a companion paper which summarises the eye care clinic during the London 2012 Olympic Games. These two reports will aid in planning eye care clinics at future Games. AIM: This paper summarises the organisation of the eye clinic and provides outline audit data relating to eye conditions encountered during the Paralympic Games. RESULTS: A total of 870 patients representing 102 countries attended the eye clinic. 274 (31.5%) were competitors; the remainder were trainers and support staff. No serious ocular injuries resulted from competitor injury in the field of play during the Paralympic Games, although seven patients were referred urgently to hospital eye services for conditions including orbital cellulitis, retinal detachment, exudative macular degeneration, corneal ulcer, Stevens-Johnson syndrome and macular oedema. A total of 749 spectacles, 14 pairs of contact lenses and 7 low vision aids were dispensed. CONCLUSIONS: By combining excellent facilities and equipment with a multidisciplinary team of eye care professionals, we feel we provided the highest level of eye care, providing a legacy for future Games.

The challenge of screening for retinopathy of prematurity.

Screening for retinopathy of prematurity (ROP) and the optimum treatment of sight-threatening disease requires detailed understanding of the infants at risk and timely identification. Despite a plethora of guidelines, not all populations and situations are adequately covered, so that what should be preventable visual disability still occurs. This article considers the design of screening guidelines and the possibility of a global guideline, although in certain parts of the world manpower for ROP screening is not available. Algorithms linked to the increase in weight of preterm infants over time may refine the number of babies needing to undergo treatment.

Seeing you through London 2012: eye care at the Olympics.

BACKGROUND: Provision of eye care services for competitors and their support teams has become an integral part of the modern Olympic Games. AIM: To describe the organisation of the eye clinic at London 2012 over a 4-week period and provide outline audit data. METHODS: The clinic employed multidisciplinary eye care professionals and utilised state-of-the-art instrumentation to provide the highest level of eye care. RESULTS: A total of 1406 patients from 154 countries attended the clinic over the Olympic Games, of which, 276 were competitors. All individuals received a comprehensive refractive and ocular health examination. Minor ocular injuries, glaucoma, diabetic retinopathy and macular degeneration were among the conditions detected and managed. Most patients attended the clinic to have their refractive status checked: 973 spectacles and 50 pairs of contact lenses were dispensed. CONCLUSIONS: It is hoped that this account of the provision of eye care at London 2012 will assist with the planning of this service at future events.

Retinal vessel changes after laser treatment for retinopathy of prematurity.

BACKGROUND: The clinical response to retinopathy of prematurity (ROP) treatment is currently assessed subjectively. This study aims to quantify treatment response objectively by assessing changes in digital images of posterior pole retinal vessel width and tortuosity. METHODS: Images of 30 right eyes with type 1 ROP obtained at up to three time points were analyzed: before treatment (T = 0) and 1 (T = 1) and/or 2 weeks (T = 2) after treatment. Width and tortuosity of retinal vessels were analyzed from digital images using computer-assisted image analysis software. RESULTS: Vessel width decreased by 20% (P < 0.004) within the first week and remained stable by the second week after laser treatment. Vessel tortuosity did not significantly change by the first week but decreased 27% (P < 0.01) by second week. CONCLUSIONS: Vessel width appears to decrease dramatic within the first week, whereas the regression of tortuosity follows a slower course.

Digital image analysis in retinopathy of prematurity: a comparison of vessel selection methods.

PURPOSE: To evaluate vessel selection methods to distinguish between eyes with and without retinopathy of prematurity (ROP) and between different stages of ROP when quantifying the associated vessel changes in width and tortuosity semiautomatically from digital retinal images. METHODS: Color digital images from 75 infants screened for ROP were cropped to a standardized diameter of 240 pixels and evaluated by semiautomated vessel analysis software, Computer-Aided Image Analysis of the Retina (CAIAR), to measure retinal vessel width and tortuosity. Two methods of vessel selection were used: (1) clinical observer selecting the most prominent arteriole or venule in each retinal quadrant (4-vessel analysis) and then separately the 4 most prominent arterioles and venules from each quadrant (8-vessel analysis); (2) CAIAR selecting, regardless of retinal quadrant, the 4 widest or most tortuous arterioles or venules. Selected vessels were measured by CAIAR for tortuosity and width. RESULTS: When comparing ROP stages, whether observer or CAIAR selected and whether 4 or 8 vessels were analyzed, we found that arteriolar tortuosity was significantly greater with advancing ROP stage for stage 0 versus stage 2; stage 0 or 1 versus stage 3; stages 1+2 combined versus stage 3; and stage 0 versus 1+2+3 combined (P < 0.01). Venular tortuosity was significantly greater with advancing ROP stage for stage 0 versus stage 3 and stage 0 versus stages 1 and 2+3 combined (P < 0.01). Width parameters did not help us to distinguish between stages. CONCLUSIONS: Distinguishing between arterioles and venules is not necessary to differentiate stage 0 ROP from stage 2 or 3 ROP when one is using CAIAR. Tortuosity shows more promise than width at providing a reliable vessel parameter for distinguishing between eyes without and with ROP.

The temporal and nasal retinal arteriolar and venular angles in preterm infants.

AIM: To determine the angle between the temporal or nasal retinal vessels in preterm infants and to determine the relationship of these angles to birthweight (BW), gestational age (GA) and retinopathy of prematurity (ROP) status. METHODS: Colour digital images were acquired during ROP screening examinations in infants born with a range of BWs and GAs between 33 and 42 weeks postmenstrual age. Four retinal vessel angles were measured: temporal venular angle, temporal arteriolar angle (tAA), nasal venular angle and nasal arteriolar angle. Measurements were performed by Computer-Aided Image Analysis of the Retina, a validated semi-automated computer software program. The relationship of each of four angles to BW and also to GA was determined using Mann-Whitney test and Spearman's rho, respectively. RESULTS: tAA was significantly narrower in infants with ROP and correlated positively with BW and GA. The other vessel angles, temporal venular angle, nasal arteriolar angle and nasal venular angle, showed no significant correlation with BW, GA or ROP status. CONCLUSION: The retinal vessel angles can be quantified in a simple repeatable manner. tAA correlated positively with BW and GA, and was significantly narrower in infants with stage 3 ROP than in those without ROP or with mild disease.

Comparison of expert graders to computer-assisted image analysis of the retina in retinopathy of prematurity.

AIMS: To determine correlation of width and tortuosity between expert graders and computer-assisted image analysis of the retina in narrow-field images of eyes with retinopathy of prematurity. METHODS: 11 digital images were selected based on severity of retinopathy of prematurity (ROP). Narrow field images were analysed for width and tortuosity of vessels using computer-aided image analysis of the retina (CAIAR), an image analysis software, and by four ROP experts. Spearman correlation coefficients (ρ) assessed the correlation of CAIAR grading with expert grading. Intra-class correlations assessed agreement among graders. Width and tortuosity were compared among severity of ROP and treatment status using analysis of variance and generalised estimating equations. RESULTS: Expert measurements correlated well with measures from CAIAR for venule width (ρ=0.57-0.66) and arteriole tortuosity (ρ=0.71-0.81). Measurements from four graders agreed moderately well (intra-class correlations were 0.49 and 0.69 for venule width and arteriole tortuosity, respectively). Increased severity of ROP (no pre-plus/plus, pre-plus, plus) was associated with larger width (linear trend p=0.02 in two graders) and tortuosity (linear trend p<0.03 in all graders). Tortuosity measurements by CAIAR and graders were statistically different between treated and untreated eyes (p<0.002). CONCLUSIONS: We found moderate correlation between expert graders' assessment of vessel tortuosity and width and CAIAR using narrow-field images.

Plus Disease: Why is it Important in Retinopathy of Prematurity?

Retinopathy of prematurity (ROP) is one of the leading causes of preventable blindness in childhood. Early posterior pole vascular signs of severe ROP have been studied since the first description of the disease. The progressive changes that take place in the posterior pole vessels of an extremely premature baby occur in a predictable fashion soon after birth. These vascular changes are described as plus disease and are defined as abnormal dilation and tortousity of the blood vessels during ROP that may go on to total retinal detachment. The ophthalmological community now has a better understanding of the pathology and cascade of events taking place in the posterior pole of an eye with active ROP. Despite many years of scientific work on plus disease, there continue to be many challenges in defining the severity and quantification of the vascular changes. It is believed that understanding of the vascular phenomenons in patients with ROP will help in designing new treatment strategies that will help in salvaging many of the eyes with severe ROP.

Semiautomated digital image analysis of posterior pole vessels in retinopathy of prematurity.

Plus disease is a major indicator for treatment in retinopathy of prematurity (ROP), and computer-assisted image analysis of vessel caliber and tortuosity in the posterior pole may indicate disease progression and severity. We sought to determine whether semiautomated digital analysis of posterior pole vessels using narrow field images with varying severity of ROP correlated with vessel width and tortuosity.

Back-calculation to model strategies for pretreatment adjustment of the ablation sphere in myopic wavefront laser in situ keratomileusis.

PURPOSE: To examine strategies for adjusting the ablation sphere in myopic wavefront laser in situ keratomileusis (LASIK) with reference to preoperative manifest refraction. SETTING: Refractive Surgery Service, Moorfields Eye Hospital, London, United Kingdom. METHODS: The variance in the 3-month postoperative manifest refraction spherical equivalent (MRSE) results in 295 consecutive cases of myopic wavefront LASIK treated with a nonsystematic, intuitive approach to pretreatment adjustment of the ablation sphere was compared with the variance in modeled results obtained by back-calculation using 4 systematic strategies: (1) no adjustment (No Adj), (2) addition of the difference between the preoperative MRSE and the preoperative 4.0 mm pupil wavefront refraction spherical equivalent (WRSE) (4.0 mm), (3) addition of the difference between the preoperative MRSE and the preoperative maximum pupil WRSE (Max), and (4) addition of the difference between the preoperative MRSE and the preoperative effective blur (EB). The EB is a theoretical value for the dioptric SE of all aberrations at the pupil size calculated for the Hartmann-Shack images acquired (wavefront diameter). A stratified analysis of results for different wavefront diameters was also performed. RESULTS: Variance in the postoperative MRSE was least (0.116) when nonsystematic, intuitive adjustments to the ablation sphere were used. In ascending order, the back-calculated variance was as follows: EB (0.142; P = .09, Bartlett test), 4.0 mm pupil (0.163; P = .004), No Adj (0.171; P = .001), and Max (0.225; P<.0001). There was a strong trend toward reduced variance in results in patients with a larger wavefront diameter. CONCLUSION: Back-calculation to model results with different pretreatment ablation adjustment strategies may be useful to eliminate unpromising new approaches before clinical trials.

Computerized analysis of retinal vessel width and tortuosity in premature infants.

PURPOSE: To determine, with novel software, the feasibility of measuring the tortuosity and width of retinal veins and arteries from digital retinal images of infants at risk of retinopathy of prematurity (ROP). METHODS: The Computer-Aided Image Analysis of the Retina (CAIAR) program was developed to enable semiautomatic detection of retinal vasculature and measurement of vessel tortuosity and width from digital images. CAIAR was tested for accuracy and reproducibility of tortuosity and width measurements by using computer-generated vessel-like lines of known frequency, amplitude, and width. CAIAR was then tested by using clinical digital retinal images for correlation of vessel tortuosity and width readings compared with expert ophthalmologist grading. RESULTS: When applied to 16 computer-generated sinusoidal vessels, the tortuosity measured by CAIAR correlated very well with the known values. Width measures also increased as expected. When the CAIAR readings were compared with five expert ophthalmologists' grading of 75 vessels on 10 retinal images, moderate correlation was found in 10 of the 14 tortuosity output calculations (Spearman rho = 0.618-0.673). Width was less well correlated (rho = 0.415). CONCLUSIONS: The measures of tortuosity and width in CAIAR were validated using sequential model vessel analysis. On comparison of CAIAR output with assessments made by expert ophthalmologists, CAIAR correlates moderately with tortuosity grades, but less well with width grades. CAIAR offers the opportunity to develop an automated image analysis system for detecting the vascular changes at the posterior pole, which are becoming increasingly important in diagnosing treatable ROP.