Syfte: Studiens syfte var att förbättra synen för närseendet för emmetropa presbyoper med tillpassade opaka infärgade pinhole linser (2 mm) och sen mäta hur dessa påverkar synskärpa, stereoseende och kontrastseende, samt jämföra detta med okorrigerad och korrigerade förhållanden för alla mätningar. Material och metoder: Mätningar för synskärpa på nära, terminal och avstånd samt stereoseende och kontrastseende utfördes tre gånger. Först utan korrektion sedan med korrektion och slutligen med opaka pinhole linsen från Nordiska Linser AB (dia 14,0 mm och baskurva 8,6 mm) i det odominanta ögat. Detta utfördes på 10 personer varav 3 exkluderades, på grund av de refraktiva kriterierna. Studiens kriterier var emmetropa presbyoper med åldersspann på 40-60 års ålder samt ej mindre pupill än 3 mm vid illumination på 85 cd/m2. Resultat: Resultatet av studien för avståndseende visade en signifikant skillnad mellan okorrigerad (-0,03 logMAR) och pinhole linsen (-0,12 logMAR) med ett p-värde på 0,05. Det fanns ingen skillnad mellan linsen och full korrektion (-0,17 logMAR). Studien visade ingen signifikant skillnad mellan okorrigerad och pinhole kontaktlinsen i de andra mätningarna (terminal p = 0,591, läsavstånd: p = 0,773, stereoseende p = 0,476, kontrastkänslighet p = 0,530). Slutsats: Pinhole kontaktlinsen visade en signifikant förbättring endast i binokulär avståndssyn jämfört med ingen korrektion. Pinhole kontaktlinser är lite bättre än okorrigerad på när- och mellanavstånd men inte lika effektiva som vid full korrigering på när- och mellanavstånd.

Yes / Purpose - Blur adaptation occurs when an observer is exposed to continuous defocus. However, it is unclear whether adaptation requires constant defocus, or whether the effect can still be achieved when the adaptation period is interrupted by short periods of clear vision. Methods - The study included 12 emmetropes and 12 myopes. All observers wore full refractive correction throughout the experiment. 1D and 3D of myopic defocus was introduced using spherical convex lenses. An automated system was used to place the blurring lens before the RE for varying periods of blurred and clear vision during adaptation. Participants watched a DVD at 3 m during each 15 min trial. Visual acuity was measured using Test Chart 2000 before and after adaptation. Results - Blur adaptation occurs to varying degrees depending on the periods of incremental blur exposure. Significant improvements in defocused visual acuity occur with continuous blur, equal blur and clear periods, as well as for longer blur periods. However, longer clear periods showed reduced adaptation and this trial is significantly different to the other three trials for both defocus levels (p < 0.001). No refractive group differences were observed for neither 1D nor 3D defocus (p = 0.58 and p = 0.19 respectively). Conclusions - Intervening periods of clear vision cause minimal disruption to improvements in defocused visual acuity after adaptation, indicating that blur adaptation is a robust phenomenon. However, when the exposure to clear vision exceeds the defocused periods, adaptation is inhibited. This gives insight into the effects of real-world tasks on adaptation to blur. / Ms Kiren A. Khan was supported by a School of Optometry and Vision Science PhD studentship.

No / The purpose of this article is to determine whether blur adaptation influences blur sensitivity and blur discrimination thresholds in young adult myopes and emmetropes. In addition, to determine whether there is a differential effect of blur adaptation on blur sensitivity and discrimination between refractive error groups. Proximal and distal blur sensitivity thresholds and blur discrimination thresholds were measured under cycloplegia with a Badal optometer in 24 young adult subjects (8 emmetropes [EMM], 8 early-onset myopes [EOM], and 8 late-onset myopes [LOM]). Adaptation to 1 D of myopic refractive blur was then undertaken for 30 minutes. Blur sensitivity and discrimination thresholds were then remeasured. After blur adaptation, blur sensitivity, and blur discrimination thresholds were found to be elevated. Blur adaptation had a significant effect on distal blur sensitivity threshold, with the largest effect being observed in the EOMs. Mean changes in distal blur sensitivity thresholds were EMMs +0.03 ± 0.14 D, EOMs +0.30 ± 0.21 D, and LOMs +0.08 ± 0.13 D. Adaptation to a degraded stimulus modifies the blur detection mechanisms of the visual system in young adults. Depth of focus is expanded by prolonged exposure to defocus. EOMs are more susceptible to this phenomenon than are LOMs and EMMs.