Subretinal membranes are associated with abnormal degrees of pupil "evasion": an index of clinical macular dysfunction.

AIM: To assess whether macular dysfunction caused by unilateral subretinal neovascular membranes (SRNs) is associated with pupil "evasion" (that is, increased initial rate of re-dilation following a brief light stimulus). METHODS: Comparative observational series. 20 eyes of 10 participants, all with unilateral SRNs and healthy fellow eyes. Dynamic infrared pupillography at seven stimulus intensities (duration 1100 ms, intensities over 2 log unit range). Pupil evasion ratio (PEVR; defined as the ratio of light response amplitude to amount of recovery at the mid-time point of re-dilation expressed as a percentage) was calculated for each stimulus intensity (mean of five recordings). RESULTS: Inter-eye PEVR is significantly reduced in eyes with SRN (that is, greater pupil evasion in SRN eyes: range p = 0.002 to p = 0.05 (paired t test)) and is most apparent at higher stimulus intensities. CONCLUSIONS: PEVR is a novel parameter that is analogous to the pupil escape ratio, but measured following a short rather than a sustained light stimulus. PEVR is significantly altered by macular disease. Clinically PEVR may be used to detect occult unilateral or asymmetric maculopathy in situations such as ocular media opacities like cataract, when pupil reactions are unaffected or augmented, while other tests of retinal function are diminished. PEVR represents altered neuronal firing in cones and macular ganglion cells.

The first cut is the deepest: basic surgical training in ophthalmology.

PURPOSE: To examine the basic surgical training received by Senior House Officers (SHOs) in ophthalmology and the influence on training of sociodemographic and organisational factors. METHODS: Cross-sectional survey of SHOs in recognised UK surgical training posts asking about laboratory training and facilities, surgical experience, demographic details, with the opportunity to add comments. RESULTS: A total of 314/466 (67%) questionnaires were returned. In all, 67% had attended a basic surgical course, 40% had access to wet labs and 39% had spent time in a wet lab in the previous 6 months. The mean number of part phakoemulsification (phako) procedures performed per week was 0.79; the mean number of full phakos performed per week was 0.74. The number of part phakos performed was negatively correlated, and the number of full phakos completed was positively correlated, with length of time as an SHO. Respondents who had larger operating lists performed more full phakos per week (P<0.001). Compared to men, women were less likely to have access to a wet lab (P=0.013), had completed fewer full phakos per week (P=0.003), and were less likely to have completed 50 full phakos (P=0003). SHOs' comments revealed concerns about their limited 'hands on' experience. CONCLUSIONS: There are significant shortcomings in the basic surgical training SHOs receive, particularly in relation to wet lab experience and opportunities to perform full intraocular procedures. SHOs themselves perceive their training as inadequate. Women are disadvantaged in both laboratory and patient-based training, but minority ethnic groups and those who qualified overseas are not.

Refractive adaptation in amblyopia: quantification of effect and implications for practice.

AIM: To describe the visual response to spectacle correction ("refractive adaptation") for children with unilateral amblyopia as a function of age, type of amblyopia, and category of refractive error. METHOD: Measurement of corrected amblyopic and fellow eye logMAR visual acuity in newly diagnosed children. Measurements repeated at 6 weekly intervals for a total 18 weeks. RESULTS: Data were collected from 65 children of mean (SD) age 5.1 (1.4) years with previously untreated amblyopia and significant refractive error. Amblyopia was associated with anisometropia in 18 (5.5 (1.4) years), strabismus in 16 (4.2 (0.98) years), and mixed in 31 (5.2 (1.5) years) of the study participants. Mean (SD) corrected visual acuity of amblyopic eyes improved significantly (p<0.001) from 0.67 (0.38) to 0.43 (0.37) logMAR: a mean improvement of 0.24 (0.18), range 0.0-0.6 log units. Change in logMAR visual acuity did not significantly differ as a function of amblyopia type (p = 0.29) (anisometropia 0.22 (0.13); mixed 0.18 (0.14); strabismic 0.30 (0.24)) or for age (p = 0.38) ("under 4 years" 0.23 (0.18); "4-6 years" 0.24 (0.20); "over 6 years" 0.16 (0.23)). CONCLUSION: Refractive adaptation is a distinct component of amblyopia treatment. To appropriately evaluate mainstream therapies such as occlusion and penalisation, the beneficial effects of refractive adaptation need to be fully differentiated. A consequence for clinical practice is that children may start occlusion with improved visual acuity, possibly enhancing compliance, and in some cases unnecessary patching will be avoided.

The state of basic surgical training in the UK: ophthalmology as a case example.

Concern is being expressed about the state of basic surgical training in the context of growing demands to improve service provision in the National Health Service. Taking ophthalmology as a case example, we sent questionnaires to all 466 senior house officers (SHOs) in recognized surgical training posts in England, Wales, Scotland and Northern Ireland. The main outcome measures were intraocular surgery performed in the previous two weeks and since starting as an SHO in ophthalmology; access to protected teaching time or cases on theatre lists; and supervision during surgery. Phakoemulsification, the most common type of cataract surgery, was used as a generic indicator of intraocular procedures. 314 (67%) of the SHOs responded. Of those working in the hospital in the previous two weeks, 50% had performed at least one component part of a phakoemulsification (phako) operation and 44% had performed at least one full phako operation. The average number of full phako operations done per week was 0.741. 77% reported some protected surgical teaching time over the two weeks and those with protected teaching time reported more full phako operations per week. Of those who had performed at least one surgical procedure in the previous two weeks, 79% had been supervised by a consultant. Of those who had completed two or more years' training as an SHO, only 42% met the Royal College of Ophthalmologists minimum requirement of 50 complete intraocular operations performed under supervision. Women were less likely than men, and SHOs in district general hospitals were less likely than those in teaching hospitals, to have achieved this target. As many as half the SHOs in ophthalmology are not receiving an adequate basic surgical training. If this continues it may prove difficult to train sufficient new surgeons to an acceptable standard to meet the increasing demands of an ageing population. This is not an issue for ophthalmology alone but for all surgical specialties.

Semiautomated computer analysis of vessel growth in preterm infants without and with ROP.

AIMS: To measure characteristics of the retinal blood vessels close to the optic disc in full term and preterm infants, with and without retinopathy of prematurity (ROP), using digital imaging. To determine whether these measures are indicative of the presence or severity of ROP in the retinal periphery. METHODS: 52 digital fundus images from 42 babies were analysed with a semiautomated analysis program developed at Imperial College London. Analysis was limited to the principal temporal vessels close to the optic disc: recording venular diameter and arteriolar diameter and tortuosity. RESULTS: Each result was categorised by the gestational age of the infant ("very premature" 24-27 weeks, "moderately premature" 28-31 weeks, and "near term" > or =32 weeks) and by the highest stage of ROP present ("no ROP," "mild ROP" stage 1 or 2, and "severe ROP" stage 3). Arteriolar tortuosity was found to vary significantly (Kruskal-Wallis p=0.002) with ROP severity. Although venular and arteriolar diameters increased monotonically with ROP severity the differences were not significant. Venular diameter, arteriolar diameter, and arterial tortuosity did not vary significantly between gestational age groups. CONCLUSIONS: This study confirms it is possible to quantify the size and tortuosity of retinal blood vessels in term and preterm babies using digital image analysis software. This method detected significant increases in arteriolar tortuosity with increasing ROP severity.

Defining and measuring treatment outcome in unilateral amblyopia.

AIM: To offer a critique of current methods of defining amblyopia treatment outcome and to examine alternative approaches. METHOD: Literature appraisal and descriptive case presentations. RESULTS: Currently, the outcome of amblyopia treatment is expressed as the number of acuity chart lines gained or, alternatively, achievement of an arbitrarily adopted level of visual acuity. As binocular vision is optimised with equal visual input from each eye the authors propose that the optimum outcome of amblyopia therapy is to achieve a visual acuity in the amblyopic eye equal to that of its fellow. In addition, improvement should be graded as the proportion of change in visual acuity with respect to the absolute potential for improvement (that is, that pertaining in the fellow eye at end of treatment). CONCLUSIONS: There are two methods of appropriately describing the outcome of amblyopia treatment: firstly, by the difference in final visual acuity of amblyopic and fellow eye (residual amblyopia); secondly, the proportion of the deficit corrected.

Design of the Monitored Occlusion Treatment of Amblyopia Study (MOTAS).

BACKGROUND/AIMS: The effectiveness of occlusion therapy for the treatment of amblyopia is a research priority. The authors describe the design of the Monitored Occlusion Treatment for Amblyopia Study (MOTAS) and its methodology. MOTAS will determine the dose-response relation for occlusion therapy as a function of age and category of amblyopia. METHODS: Subjects progress through up to three study phases: (1) Assessment and baseline phase: On confirmation of eligibility, and after parental consent, baseline visual functions are determined, and spectacles prescribed as necessary; (2) Refractive adaptation phase: Subjects wear spectacles full time and return to clinic at 6 weekly intervals until 18 weeks, by which time all improvement due to refractive correction is complete; (3) Occlusion phase: All subjects are prescribed 6 hours of occlusion per day. Daily occlusion is objectively monitored using an occlusion dose monitor (ODM). OUTCOME VARIABLES: visual acuity (logMAR charts), log contrast sensitivity (Pelli-Robson chart), and stereoacuity (Frisby) are assessed at 2 weekly intervals until gains in visual acuity cease to be statistically verifiable. CONCLUSION: Four methodological issues have been addressed; firstly, baseline stability of visual function; secondly, differentiation of refractive adaptation from occlusion; thirdly, objective measurement of occlusion dose and concordance; fourthly, use of validated outcome measures.

Environmental light and the preterm infant.

The lighting environment of the preterm baby is quite unlike that experienced at any other time of life. Physical and physiological factors control how much light reaches the retina of the preterm baby. With respect to the former, although many neonatal intensive care units are brightly and continuously lit, there is a trend to employ lower levels of illumination and to introduce cycling regimens. Physiological determinants of the retinal light dose include: eyelid opening and transmission, pupil diameter and the transmission characteristics of the ocular media. Early exposure to light does not significantly hasten or retard normal visual development, and it is not a factor in the development of retinopathy of prematurity. However, ambient neonatal intensive care unit illumination may be implicated in some of the more subtle visual pathway sequelae that cannot be attributed to other major complications of preterm birth including altered visual functions and arrested eye growth.

Treating pancreatitis in the acute care setting.

Acute pancreatitis is associated with significant complications and mortality. This article describes the pathophysiology and complications of, and treatments for acute pancreatitis, and the nurse's role in caring for a patient in the acute care setting.

Reliability and validity of the Food Pyramid Self Efficacy Scale: use in coronary artery bypass patients.

Inappropriate dietary intake is associated with 5 of the 10 leading causes of U.S. death; coronary artery disease (CAD) ranks highest regardless of gender in people over the age of 65. Of the modifiable risk factors for CAD, two of four pertain to food choices. Although lifestyle habits can enhance or impair health, people's beliefs that they can motivate and regulate their own behavior (self efficacy) plays a crucial role in whether they even consider changing detrimental health habits. The Food Pyramid Self Efficacy Scale (FPSES) is an instrument to measure an elder's confidence in his/her ability to choose healthy food items in a variety of situations. The purpose of this study was to determine the reliability and validity of the FPSES. Thirty postoperative CABG patients participated (mean age 70.4). FPSES test-retest (r = 0.78, p = 0.008); coefficient alpha = 0.92. Six content experts judged the FPSES (content validity index [CVI] = 0.85). Construct validity of the instrument was achieved through hypothesis testing, supporting the statement that the higher the nutritional risk, the greater the functional decline (r = 0.37, p = 0.05). As many of the health problems associated with the elderly are preventable or controllable through health promotion, it is vital that measures exist to determine a person's confidence that one believes in the capability to change to healthy eating behaviors.

Delayed visual maturation: pupillary responses implicate subcortical and cortical visual systems.

Vision in very early infancy is probably subserved by subcortical pathways, with many cortical processes only fully emerging by 3 months of age. The improvement of vision in delayed visual maturation (DVM) occurs around this time, and this has given rise to the suggestion that the condition may have a subcortical basis that resolves with the appearance of cortical function. To explore further the role of cortical and subcortical visual systems in DVM we studied the visual development in identical twins, one of whom had type 1b DVM. Two non-invasive methods of investigating visual pathway function were employed: the acuity card procedure (a behavioural response) and luminance and grating pupillometry. While the former reflects both subcortical and cortical function and can be detected at birth, pupil responses to gratings reflect cortical activity alone and normally become measurable at 1 month of age. Development of both behavioural and pupillary responses was delayed in DVM, indicating that although the underlying defect is primarily subcortical, secondarily it delays the emergence of cortically mediated responses. The observed rapidity of improvement--over a very few days and within a narrow age range--suggests a discrete rather than a widespread structural abnormality, the improvement of which is closely linked to postmenstrual age.

Graphical representation of visual acuity data.

Accurate graphical depiction of data requires that distances between points map precisely to the quantitative differences they represent. In the case of Snellen visual acuity, consecutive line sizes do not generally correspond to equal increments in visual angle, hence scores plotted against axes marked off in equal intervals provide a false representation of the relation between plotted values. A worked example illustrates the nature of this problem and its solution.

Perioperative problems: nutrition and electrolytes in the elderly.

Nutrition plays a pivotal role in health promotion, disease prevention, chronic disease management, and perioperative treatment. The normal physiological changes of aging place the elder at risk for complications during the perioperative period. The most important principle in limiting the possibility of perioperative complications is prevention.

Effectiveness of occlusion therapy in ametropic amblyopia: a pilot study.

AIMS/BACKGROUND: To examine the relative contributions of non-specific (for example, spectacle correction) and specific (that is, occlusion therapy) treatment effects on children with ametropic amblyopia. To assess the importance and practicality of objectively confirming the prescribed occlusion dose. METHODS: Subjects were entered into a two phase trial. In the first ('pretreatment') subjects were provided with spectacle correction and underwent repeat visual acuity (VA) and contrast sensitivity (CS) testing until acuity in their amblyopic eye had stabilised. Subjects then progressed to the second phase ('treatment') in which they underwent direct, unilateral occlusion for 1 hour per day for 4 weeks. Patching was objectively monitored using an occlusion dose monitor. RESULTS: Eight subjects completed the trial, all but one of whom achieved > 80% concordance with the occlusion regimen. Within the pretreatment phase, mean amblyopic eye VA improved by 0.19 log units (p = 0.008) while mean CS gained 0.09 log units (p = 0.01). An identical improvement in mean VA was recorded in the fellow eyes (p = 0.03) while mean CS gained 0.11 log units (p = 0.02). Within the treatment phase, mean VA further improved (0.12 log units, p = 0.009) although this gain had halved by the end of treatment and was no longer statistically significant (p = 0.09). CONCLUSIONS: Visual performance improved significantly during pretreatment whereas further gains seen during occlusion were not sustained. Evaluation of occlusion regimens must take into consideration the potentially confounding influence of 'pretreatment effects' and the necessity to confirm objectively the occlusion dose a child receives.