Patient-reported benefit from oculoplastic surgery.

PURPOSE: It is vital that surgeons undertaking oculoplastic procedures are able to show that the surgery they perform is of benefit to their patients. Not only is this fundamental to patient-centred medicine but it is also important in demonstrating cost effectiveness. There are several ways in which benefit can be measured, including clinical scales, functional ability scales, and global quality-of-life scales. The Glasgow benefit inventory (GBI) is an example of a patient-reported, questionnaire-based, post-interventional quality-of-life scale that can be used to compare a range of different treatments for a variety of conditions. METHODS: A cross-sectional study was undertaken using the GBI to score patient benefit from four commonly performed oculoplastic procedures. It was completed for 66 entropion repairs, 50 ptosis repairs, 41 ectropion repairs, and 41 external dacryocystorhinostomies (DCR). The GBI generates a scale from -100 (maximal detriment) through zero (no change) to +100 (maximal benefit). RESULTS: The total GBI scores of patients undergoing surgery for entropion, ptosis, ectropion, and external DCR were: +25.25 (95% CI 20.00-30.50, P<0.001), +24.89 (95% CI 20.04-29.73, P<0.001), +17.68 (95% CI 9.46-25.91, P<0.001), and +32.25 (95% CI 21.47-43.03, P<0.001), respectively, demonstrating a statistically significant benefit from all procedures. CONCLUSION: Patients derived significant quality-of-life benefits from the four most commonly performed oculoplastic procedures.

Characteristics of rhegmatogenous retinal detachment in pseudophakic and phakic eyes.

AIMS: To investigate whether pseudophakic and phakic rhegmatogenous retinal detachment (RRD) patterns differ. METHODS: Retrospective review of electronic database of patients, aged 50 years or over, presenting to our vitreoretinal service. Data included baseline characteristics, digital drawings, and outcomes. Retinal drawings were analysed in a masked fashion for site, size, and number of retinal breaks. Comparisons were made between the following groups and subgroups: pseudophakic eyes, phakic eyes, phakic eyes with cataract, and phakic eyes without cataract. RESULTS: Of 500 eyes included, 146 were pseudophakic; 177 of the phakic eyes had cataract. The following were significant by univariate analysis: pseudophakic patients were older than phakic patients in general, but the same age as patients with cataract; in the pseudophakic group, there were lower proportions of females and of patients presenting with vitreous haemorrhage or with large or superotemporal breaks; higher proportions of pseudophakic eyes had small breaks and inferonasal breaks. Some differences remained significant when comparing pseudophakia eyes with cataract. Multivariate analysis comparing pseudophakia with phakia confirmed a lower chance in pseudophakia of large breaks, vitreous haemorrhage and superotemporal breaks, but higher chance of detached inferior breaks. Some variables were age dependent. CONCLUSION: Differences were found between pseudophakic and phakic RRD patterns. These suggest special pathogenetic mechanisms in pseudophakic retinal detachment, which could help explain increased incidences of RRD after cataract surgery.

Dark adaptation of human rod bipolar cells measured from the b-wave of the scotopic electroretinogram.

To examine the dark adaptation of human rod bipolar cells in vivo, we recorded ganzfeld ERGs to (a) a family of flashes of increasing intensity, (b) dim test flashes presented on a range of background intensities, and (c) dim test flashes presented before, and up to 40 min after, exposure to intense illumination eliciting bleaches from a few per cent to near total. The dim flash ERG was characterized by a prominent b-wave response generated principally by rod bipolar cells. In the presence of background illumination the response reached peak earlier and desensitized according to Weber's Law. Following bleaching exposures, the response was initially greatly desensitized, but thereafter recovered slowly with time. For small bleaches, the desensitization was accompanied by acceleration, in much the same way as for real light. Following a near-total bleach, the response was unrecordable for >10 min, but after approximately 23 min half-maximal sensitivity was reached, and full sensitivity was restored between approximately 35 and 40 min. With smaller bleaches, recovery commenced earlier. We converted the post-bleach measurements of desensitization into 'equivalent background intensities' using a Crawford transformation. Across the range of bleaching levels, the results were described by a prominent 'S2' component (0.24 decades min(-1)) together with a smaller and slower 'S3' component (0.06 decades min(-1)), as is found for dark adaptation of the scotopic visual system. We attribute the S2 component to the presence of unregenerated opsin, and we speculate that the S3 component results from ion channel closure by all-trans retinal.

Extremely rapid recovery of human cone circulating current at the extinction of bleaching exposures.

We used a conductive fibre electrode placed in the lower conjunctival sac to record the a-wave of the human photopic electroretinogram elicited by bright white flashes, delivered during, or at different times after, exposure of the eye to bright white illumination that bleached a large fraction (approximately 90%) of the cone photopigment. During steady-state exposures of this intensity, the amplitude of the bright-flash response declined to approximately 50% of its dark-adapted level. After the intense background was turned off, the amplitude of the bright-flash response recovered substantially, for flashes presented within 20 ms of background extinction, and fully, for flashes presented 100 ms after extinction. In addition, a prominent 'background-off a-wave' was observed, beginning within 5-10 ms of background extinction. We interpret these results to show, firstly, that human cones are able to preserve around half of their circulating current during steady-state illumination that bleaches 90% of their pigment and, secondly, that following extinction of such illumination, the cone circulating current is restored within a few tens of milliseconds. This behaviour is in stark contrast to that in human rods, where the circulating current is obliterated by a background that bleaches only a few percent of the pigment, and where full recovery following a large bleach takes at least 20 min, some 50,000 times more slowly than shown here for human cones.

Recovery of the human photopic electroretinogram after bleaching exposures: estimation of pigment regeneration kinetics.

We used a fibre electrode in the lower conjunctival sac of the human eye to record the a-wave of the photopic electroretinogram elicited in response to dim red flashes, delivered in the presence of a rod-saturating blue background, before and after exposure of the eye to bright white illumination that bleached a significant fraction of cone photopigment. Responses were recorded from two normal subjects whose pupils were maximally dilated. A range of intensities of bleaching light were used, from 500 to 3000 photopic cd m(-2), and exposures were made sufficiently long in duration to achieve a steady-state bleach. In addition, responses were also recorded following shorter durations of exposures to the highest intensity (3000 cd m(-2)); these durations ranged from 5 to 60 s. The amplitude of the a-wave response to dim flashes was reduced following the exposures, with brighter or longer exposures causing greater reduction. The amplitude then recovered within about 4 min to the prebleach level. The amplitudes measured at ca 15 ms after the flash were used to derive the effective intensity of the flashes, thereby quantifying the fraction of photopigment available at the time of delivery of each flash. Recovery from all exposures in both subjects followed a common time course, which could be described well by a model of pigment kinetics based on rate-limited regeneration, where the initial rate of recovery following a total bleach was ca 50% of the total pigment per minute, and the residual pigment level for half the maximal rate was ca 20% of the total pigment. The same parameters, together with a fixed photosensitivity, could account for the steady-state pigment levels seen at each bleaching intensity, and also for the fraction of pigment bleached following exposures of different duration at the highest intensity. The dim-flash ERG thus provides a novel method for assessing pigment regeneration in vivo. Our finding that pigment regeneration follows rate-limited kinetics may explain previous reports of pigment regeneration deviating from first order kinetics. We present a model of regeneration in which the rate limit arises from a limitation in the delivery of 11-cis-retinoid to the photoreceptor outer segments.