Photopic Contrast Sensitivity Research Articles

Improvement or Worsening of Human Contrast Sensitivity Due to Blue Light Attenuation at 450 nm.

PurposeThe work was aimed at comparing contrast sensitivity performance in an indoor environment with two filters, which differ only in the presence of a band at 450±20 nm in the transmittance spectrum.Patients and MethodsThirty-nine subjects participated. The filters were the Standard (ST) and Professional (PRO) Drive lenses (Hoya, Japan), the latter showing the attenuation band at 450 nm. Photopic contrast sensitivity (CS) was measured at different spatial frequencies from 1.5 to 18 cpd through Functional Acuity Contrast Test with both lenses (LogCSST and LogCSPRO, respectively). The areas under the curves of LogCSST and LogCSPRO as a function of the spatial frequency were also considered.ResultsIn the range of the measured values of LogCSST for the thirty-nine participants, at each spatial frequency and also for the areas, the difference Δ = LogCSPRO – LogCSST was found to decrease and change sign from positive to negative as a function of LogCSST, thus allowing to deduce a threshold (LogCSthreshold) for LogCSST corresponding to Δ=0. Significant CS worsening was found with the PRO compared to the ST lens for the subjects showing LogCSST > LogCSthreshold. Vice versa, CS improvement was found when LogCSST < LogCSthreshold.ConclusionIn the choice of a blue-filtering lens, practitioners should take into consideration that the attenuation of light in the range 420–470 nm is expected to produce a CS worsening in subjects showing a relatively high initial CS (higher than a threshold CS). For these subjects, the general reduction of transmitted light intensity prevails on possible advantages. On the contrary, subjects showing a relatively low initial CS are expected to show a CS improvement because the attenuation of light in the range 420–470 nm is expected to reduce intraocular scattering and to mimic the effect as an optical filter of the human macular pigment, advantages which prevail on the reduction of the transmitted light intensity.

Comparison of contrast sensitivity between three aspheric acrylic monofocal intraocular lenses: a prospective randomised trial

Introduction: Evolution of cataract surgery and implantation of intraocular lenses (IOL) with new technological designs to optimise functional vision has been the aim of cataract surgery today. Aspherical lens design is a new lens technology to counteract spherical aberration exerted by a conventional IOL.&#x0D; Purpose: To compare the contrast sensitivity after cataract surgery between aspheric IOLs with negative spherical aberration (Tecnis ZA9003TM and AcrySof IQTM) and zero spherical aberration IOLs (Akreos Adapt Advance Optic [AO]TM).&#x0D; Study design: Interventional, single-blinded, randomised controlled trial.&#x0D; Methods: Ninety-six patients were recruited with 32 eyes in each study arm. All patients underwent standard phacoemulsification with implantation of an aspheric acrylic IOL randomised to one of the three lens models by a single experienced surgeon. Pre- and postoperative contrast sensitivity was analysed using the CSV1000E chart under photopic and mesopic conditions with and without glare testing.&#x0D; Results: All three lenses showed statistically significant improvement in contrast sensitivity postoperatively at all spatial frequencies under photopic, mesopic, and scotopic conditions with glare. There was no statistically significant difference between the groups. Tecnis ZA9003TM showed marked improvement in mesopic contrast sensitivity at 18 cycles/degree (cpd) at 12 weeks (p &lt; 0.05). The zero aberration Akreos Adapt AOTM showed better photopic contrast sensitivity compared to mesopic contrast sensitivity (p &gt; 0.05).&#x0D; Conclusion: AcrySof IQTM, Akreos Adapt AOTM, and Tecnis ZA9003TM performed equally well in contrast sensitivity at all spatial frequencies under photopic and mesopic conditions with and without glare testing. All lenses had statistically significant improvement in contrast sensitivity after cataract surgery. The negative aberration IOL Tecnis ZA9003TM showed marked improvement in mesopic contrast sensitivity at 18 cpd at 12 weeks. The zero aberration IOL, Akreos Adapt AOTM showed better photopic contrast sensitivity compared to mesopic contrast sensitivity.

Association of Photopic and Mesopic Contrast Sensitivity in older drivers with risk of motor vehicle collision using naturalistic driving data

BackgroundOlder drivers have a crash rate nearly equal to that of young drivers whose crash rate is the highest among all age groups. Contrast sensitivity impairment is common in older adults. The purpose of this study is to examine whether parameters from the photopic and mesopic contrast sensitivity functions (CSF) are associated with incident motor vehicle crash involvement by older drivers.MethodsThis study utilized data from older drivers (ages ≥60 years) who participated in the Strategic Highway Research Program Naturalistic Driving Study, a prospective, population-based study. At baseline participants underwent photopic and mesopic contrast sensitivity testing for targets from 1.5–18 cycles per degree. Model fitting generated area under the log CSF (AULCSF) and peak log sensitivity. Participant vehicles were instrumented with sensors that captured continuous driving data when the vehicle was operating (accelerometers, global positioning system, forward radar, 4-channel video). They participated for 1–2 years. Crashes were coded from the video and other data streams by trained analysts.ResultsThe photopic analysis was based on 844 drivers, and the mesopic on 854 drivers. Photopic AULCSF and peak log contrast sensitivity were not associated with crash rate, whether defined as all crashes or at-fault crashes only (all p > 0.05). Mesopic AULCSF and peak log sensitivity were associated with an increased crash rate when considered for all crashes (rate ratio (RR): 1.36, 95% CI: 1.06–1.72; RR: 1.28, 95% CI: 1.01–1.63, respectively) and at-fault crashes only (RR: 1.50, 95% CI: 1.16–1.93; RR: 1.38, 95% CI: 1.07–1.78, respectively).ConclusionsResults suggest that photopic contrast sensitivity testing may not help us understand future crash risk at the older-driver population level. Results highlight a previously unappreciated association between older adults’ mesopic contrast sensitivity deficits and crash involvement regardless of the time of day. Given the wide variability of light levels encountered in both day and night driving, mesopic vision tests, with their reliance on both cone and rod vision, may be a more comprehensive assessment of the visual system’s ability to process the roadway environment.

Refractive and Visual Outcomes After Bilateral Implantation of a Trifocal Intraocular Lens in a Large Population.

PurposeTo review refractive, visual acuity, defocus curve and contrast sensitivity results after bilateral implantation of a trifocal intraocular lens (IOL) in a large population.SettingOne site in Santiago, Chile.DesignSingle arm, non-randomized retrospective chart review.MethodsThis was a single-arm retrospective chart review of clinical outcomes after bilateral implantation of a trifocal IOL (Panoptix®), both toric and non-toric versions. Binocular visual acuity at 4 m, 60 cm and 40 cm was tested. Other tests included refraction, mesopic and photopic contrast sensitivity, and defocus curve measurement.ResultsThe review included 500 eyes of 250 patients implanted with the trifocal IOL and 200 eyes of 100 patients implanted with the trifocal toric IOL, with no clinically significant differences between groups. Ninety-six percent of all eyes were within 0.50D of the intended spherical equivalent correction. In the toric group, 94% of eyes (187/200) had a residual refractive cylinder ≤0.50D, compared to 81% of eyes (406/500) in the non-toric group. Four out of five patients (80.6%, 282/350) had a binocular uncorrected VA of 0.1 logMAR (20/25) at all test distances. Mean defocus was 0.1 logMAR or better from vergences from 0.00 to −3.00 D (corresponding to vision from distance to about 33 cm). With a cutoff of 0.2 logMAR, 96% of patients had a range of vision 2.5 D or greater. Contrast sensitivity was similar between the toric and non-toric lenses, and similar to age-matched normal results.ConclusionThe non-toric and toric trifocal IOLs provided good distance, intermediate and near vision to patients, with a wide range of vision and good contrast sensitivity.

The effects of two longpass filters on visual performance

PurposeThis study compared visual performance and optical properties of three filters. MethodTwo groups of twenty adults were recruited: wearers of progressive addition lenses (PAL, 46–73 years) and wearers of single vision lenses (SVL, 26–55 years). Three spectacle filters (Hoya, Japan) were compared: clear control, Standard Drive (STD), and Professional Drive (PRO) lenses. Optical transmittance was measured by a Jasco V-650 spectrophotometer. Best corrected visual acuity (BCVA) was measured in photopic (BCVAphotopic) and mesopic (BCVAmesopic) conditions and under glare (BCVAglare). Photopic contrast sensitivity (CS) was also measured. ResultsThe three longpass filters show cutoff at 426±2nm (STD/PRO) and 405±2nm (clear lens). BCVAglare improved with Drive filters compared to the clear one (p<0.05) from 0.03 to -0.02 (STD) and to -0.01 (PRO) for PAL and from -0.08 to -0.12 (STD and PRO) for SVL. For PAL, BCVAmesopic improved from 0.15 to 0.12 (STD, p<0.05) and 0.13 (PRO), while no substantial difference was observed for SVL. CS showed some improvements with Drive lenses at some angular frequencies between 6 and 18 cycles/deg, mainly for the PAL group. No BCVAphotopic differences were found. After testing all filters, each for two weeks, 79% (PAL) and 60% (SVL) of participants preferred Drive lenses. ConclusionsDrive lenses are found to maintain or improve some visual functions compared to the clear lens. The improvement of mesopic visual acuity, visual acuity under glare, and contrast sensitivity is mainly attributed to the reduction of intraocular light scattering as a consequence of the total light attenuation in the spectral range below the cutoff.

Functional results and photic phenomena with new extended-depth-of-focus intraocular Lens

BackgroundEvaluation of clinical and functional results of a new extended depth of focus intraocular lens (EDOF-IOL).MethodsFourteen cataract patients (28 bilateral implantations) were assessed for uncorrected (UDVA) and corrected (CDVA) distance visual acuities; uncorrected (UNVA), distance-corrected (DCNVA) and best corrected (CNVA) near visual acuities; and uncorrected (UIVA) and distance-corrected (DCIVA) intermediate visual acuities - as well as binocular defocus curves. Photopic and mesopic contrast sensitivity was recorded. Reading acuity was evaluated using an electronic reading desk at fixed distances and at the patient’s preferred near and intermediate distances. Visual symptoms were assessed with a halo and glare simulator plus a patient questionnaire which also recorded quality of life.ResultsMedian postoperative monocular UDVA was 0.13logMAR (range − 0.08 to 0.42logMAR), median CDVA was − 0.01logMAR (range − 0.20 to 0.22logMAR), median UIVA at 80 cm was − 0.05logMAR (range − 0.18 to 0.58logMAR) and median UNVA at 40 cm was 0.14logMAR (range − 0.10 to 0.64logMAR). Binocular uncorrected reading acuity was 0.10logMAR at 40 cm and 0.11logMAR at 80 cm. Patients preferred a median intermediate reading distance of 62.8 cm over the predetermined 80 cm, which allowed them to read smaller letter size but did not improve reading acuity. Patients reported a high rate of spectacle independence and satisfaction in everyday life and little to no dysphotopsia.ConclusionThe Mini WELL Ready IOL provided good postoperative functional results at far and intermediate distances and improved the visual and reading acuity at reading distance. The lens caused little to no dysphotopsia.Trial registrationThe study protocol was registered at the German Clinical Trials Register: DRKS00007837 (Registered Date: March 9th, 2015).

The impact of uncorrected astigmatism on night driving performance.

To investigate the effect of uncorrected astigmatism on night driving performance on a closed-road circuit. Participants included 10 drivers (mean age 24.4±7.0years), with low to moderate bilateral astigmatism (0.75-1.50 DC), who were regular contact lens (CL) wearers. Vision and night driving performance were assessed in a cross-over design with a toric CL and a best-sphere spherical CL. Binocular visual function measures included photopic and mesopic visual acuity (VA), contrast sensitivity (CS), mesopic motion sensitivity and glare tests (Mesotest® II and Halometer). Night-time driving performance was assessed on a closed-road circuit, which included measures of sign recognition, hazard detection and avoidance, pedestrian recognition distances, lane keeping, speed and overall driving score. Correction of astigmatism with toric CL significantly improved mesopic VA, photopic and mesopic CS, mesopic motion sensitivity, and reduced glare (p<0.05), compared to the spherical CL; there were no significant effects of visual correction type on photopic VA. Correction of astigmatism using toric CL resulted in significant improvements in night driving performance, compared to driving with spherical CL, particularly for sign recognition, avoidance of low contrast hazards, increased pedestrian recognition distances and overall driving score (p<0.05). Correction of low to moderate levels of astigmatism had significant positive effects on night-time driving performance and related tests of visual performance. This has important implications for optical corrections to improve night road safety of drivers with astigmatism.

Implantation of a diffractive–refractive trifocal intraocular lens with centralized diffractive rings: Two-year results

To compare the optical performance and quality of life after implantation of a new progressively apodized diffractive multifocal intraocular lens (IOL) and report the visual and patient-reported outcomes and contrast sensitivity. Csolnoky Ferenc Hospital, Veszprem, Hungary. Prospective case series. Patients had bilateral implantation of the trifocal IOL during cataract surgery. The preoperative corrected distance visual acuity (CDVA) and postoperative uncorrected distance visual acuity (UDVA), CDVA, uncorrected (UIVA) and corrected (CIVA) intermediate visual acuities, and uncorrected (UNVA) and corrected (CNVA) near visual acuities (all logarithm of the minimum angle of resolution) were collected. Contrast sensitivity, slitlamp photographs for evaluation of posterior capsule opacification, and a quality-of-vision questionnaire were assessed. The study comprised 100 eyes (50 patients). The mean postoperative UDVA was 0.01 at 3, 6, 12, and 24months. The mean CDVA was -0.02±0.03 (SD) at 6months, -0.04±0.05 at 1year, and 0.06±0.05 at 2years. The mean UIVA was 0.05±0.11, 0.04±0.09, and 0.06±0.11, respectively. The mean CIVA was -0.01±0.07, -0.02±0.06, and -0.01±0.07, respectively. The mean UNVA was 0.08±0.08, 0.07±0.08, and 0.10±0.09, respectively. The mean CNVA was 0.03±0.06 at 3months, 0.04±0.05 at 1year, and 0.05±0.07 at 2years. The mesopic and photopic contrast sensitivity values were within the upper normal range for age-matched values. Bilateral implantation of a new trifocal IOL with centralized diffractive rings provided good functional vision at alldistances. The levels of spectacle independence and patient satisfaction were high with minimal dysphotopsia symtoms.

Visual Performance, Subjective Satisfaction and Quality of Life Effect of a New Refractive Intraocular Lens with Central Extended Depth of Focus.

To assess the visual performance, clinical and quality of life outcomes, and subjective patient satisfaction after implantation of a new refractive/extended depth of focus (EDOF) hybrid intraocular lens (IOL). This is a monocentric, retrospective study of 29 patients (45 eyes), carried out in a tertiary care glaucoma research centre. All patients underwent implantation of a Lucidis (Swiss Advanced Vision, SAV-IOL SA, Neuchâtel, Switzerland) IOL during cataract surgery. Near, intermediate, and distance best-corrected visual acuities and uncorrected visual acuities were collected at baseline and 3 months postoperatively. Adverse events, contrast sensitivity, optical aberrations, subjective satisfaction, and spectacle independence were also analysed at 3 months. At 3 months postoperatively, the mean photopic uncorrected monocular distance, and intermediate and near visual acuities were 0.2 logMAR (~ 20/32), 0.07 logMAR (~ 20/23), and 0.15 logMAR (~ 20/28), respectively. Mean best-corrected visual acuity was 0.05 logMAR (~ 20/23) for distance and 0.03 logMAR (~ 20/21) for near vision. Mean photopic contrast sensitivity was 1.5 log. The mean root mean square (RMS) was 0.119 ± 0.05 µm. Subjectively, over the 3-month follow-up, 9% of patients (n = 4) complained of halos, and 2% (n = 1) of photophobia. No other adverse events were noted. The Lucidis IOL demonstrates a good safety profile, with an acceptably low complication rate. While the uncorrected visual performance of this new optical design is inferior to that of other EDOF IOLs for distance vision, it achieves better results in intermediate and near vision, with consistently near-normal contrast sensitivity. Interestingly, self-reported spectacle independence and subjective patient satisfaction were high for all distances.

Correlating macular inner retinal layer thickness with photopic and mesopic contrast sensitivity in healthy young and older subjects

Correlating macular inner retinal layer thickness with photopic and mesopic contrast sensitivity in healthy young and older subjects

Macular Inner Retinal Layer Thickness in Relation to Photopic and Mesopic Contrast Sensitivity in Healthy Young and Older Subjects.

To examine relationships between the thicknesses of ganglion cell (GC)-related macular layers and central photopic or mesopic contrast sensitivity (CS) in healthy eyes. Measurements were made in 38 young and 38 older healthy individuals. Total, inner, and outer retinal layer (IRL) thicknesses were measured in the macula region through spectral-domain optical coherence tomography (SD-OCT) across three subfields, or rings, centered at the fovea: central foveal, pericentral, and peripheral. Ganglion cell complex and circumpapillary retinal nerve fiber layer thicknesses were also measured. Low-spatial-frequency CS for gratings presented at the central 10° visual field were measured through computerized psychophysical tests under photopic and mesopic conditions. Relationships were examined by uni- and multivariate regression analysis. Peripheral IRL thickness emerged as the only independent predictor of photopic CS (P = 0.001) in the young group and of photopic (P = 0.026) and mesopic CS (P = 0.001) in the older group. The slopes of regression lines used to predict CS from peripheral IRL thickness were significantly different for pair-wise comparisons of both photopic CS and age group (P = 0.0001) and mesopic CS (P = 0.0001) and age group. These models explained 37% of the variability in photopic CS and 36% of the variability in mesopic CS. Macular IRL thinning likely due to GC loss was related to reduced photopic and mesopic CS in older healthy eyes. In contrast, in the young eyes, a thicker macular IRL, possibly indicating transient gliosis, was associated with reduced CS.

Early Changes in Visual Quality and Corneal Structure after DMEK: Does DMEK Approach Optical Quality of a Healthy Cornea?

Purpose To evaluate early changes in visual function and visual quality parameters after Descemet membrane endothelial keratoplasty (DMEK) and to compare the outcomes with healthy controls. Methods Thirteen patients who underwent DMEK and 14 controls were evaluated. All subjects underwent visual function evaluation, including visual acuity under photopic and mesopic lighting conditions and contrast sensitivity (CSV) tests CSV 1000 and Pelli-Robson. Corneal parameters were assessed with Oculus Pentacam. Corneal mean keratometry (Km), corneal densitometry values, and low and high order aberrations (LOA and HOA) were recorded. In DMEK patients, all tests were performed before surgery and 1 and 6 months after surgery. Results In patients who underwent DMEK, photopic visual acuity improved from 0.59 to 0.31 at 1 month (p=0.013) and 0.13 at 6 months (p=0.008); mesopic visual acuity and all contrast sensitivity values (both CSV and Pelli-Robson test) improved significantly in the first month (p < 0.005). A significant decrease was observed in corneal density in the 0–2 mm ring (from 43.83 to 35.60, p=0.043) and mean posterior Km (from −5.84 to −6.80, p=0.005) in the first month. Corneal HOAs and all corneal densities improved at 6 months after DMEK (p < 0.05). All visual function parameters and corneal aberrations remained lower and higher, respectively, compared with healthy controls (p < 0.05). Corneal densities were comparable with controls at 6 months after DMEK (p > 0.05). Conclusions Patients undergoing DMEK present visual function improvement and a decrease in corneal density at 1 month after surgery. Decrease in corneal posterior HOAs can be observed at 6 months. However, visual function outcomes and corneal aberrations remained worse compared with healthy controls.

First results with a new intraocular lens design for the individual correction of spherical aberration

To assess the feasibility of individual compensation of corneal spherical aberration with a custom intraocular lens (IOL). Department of Ophthalmology, Rudolf Virchow Klinikum Glauchau, Glauchau, Germany. Prospective case series. Cataract patients were randomized to receive an individual aberration-correcting IOL (Invidua-aA; Group A) or a standard aspheric aberration-free IOL of otherwise identical design (Aspira-aA; Group B). In Group A, the IOL was designed according to preoperative calculation of the corneal spherical aberration Z(4,0). The aim was to achieve an overall postoperative ocular spherical aberration close to zero. Four weeks and 3months postoperatively, the refraction, visual acuity (far, intermediate, and near distance), photopic and mesopic contrast sensitivities (with and without glare), defocus curve, corneal and ocular spherical aberration, and pupil size were measured. Group A, 57 eyes of 42 patients and Group B, 29 eyes of 27 patients. Preoperatively, there was no difference in corneal spherical aberration between groups (P>.05). Three months postoperatively, residual ocular spherical aberration Z(4,0) was significantly lower in Group A (P<.001). Photopic and mesopic contrast sensitivities (with and without glare) were significantly higher in Group A at most spatial frequencies. Monocular defocus curve and distance, intermediate, and near visual acuity outcomes did not differ significantly between groups. Implantation of a custom monofocal aspheric IOL effectively reduced overall ocular spherical aberration. Clinical outcomes indicate that IOLs with an individual spherical aberration correction improve functional vision, especially contrast sensitivity, compared with standard aberration-free IOLs.

Corneal Cap Thickness and Its Effect on Visual Acuity and Corneal Biomechanics in Eyes Undergoing Small Incision Lenticule Extraction.

Purpose To evaluate the effect of corneal cap thickness on visual acuity and corneal biomechanics in small incision lenticule extraction (SMILE) for the treatment of myopia. Methods Forty eyes of 20 patients undergoing SMILE for the treatment of myopia were enrolled in this prospective controlled study. The patients with 510 μm–560 μm central corneal thickness (CCT) and a refractive spherical equivalent of −3.00 D to −8.00 D were included. It was designed randomly to undergo SMILE with a 110 μm cap thickness in one eye and 150 μm cap thickness in the other. Ophthalmic examinations included best-corrected and uncorrected visual acuity (UCVA); refractive status, contrast sensitivity, and objective visual quality were evaluated at 2 h, 4 h, and 24 h postoperatively; while at 3 months after the procedure, corrected intraocular pressure (IOP), higher order aberrations (HOAs), and morphologic modifications of corneal architecture of both eyes were assessed. Results Compared with the 150 μm group, the incidence of OBL was significantly higher in the 110 μm cap thickness group (P=0.004), and UCVA, Strehl ratio (SR), objective scatter index (OSI), modulation transfer function (MTF) cutoff frequency, and photopic and scotopic contrast sensitivity at medium spatial frequency were all significantly better in 110 μm group at 2 h and 24 h postoperatively (P < 0.05). Corneal spherical aberration and corrected IOP by Corvis ST were significantly higher in the 110 μm group at 3 months postoperatively (P < 0.05). No statistically significant differences were found in manifest refraction, UCVA, SR, OSI, MTF cutoff, and mesopic and photopic contrast sensitivity at low frequency, photopic contrast sensitivity at high frequency, endothelial density, corneal coma, and total HOAs at 3 months after the procedure. No visual decline was found in the patients in this study. Conclusions Both 110 μm and 150 μm cap thickness in SMILE were safe and effective for treatment of myopia. A 110 μm cap thickness demonstrated better visual outcomes during early and late postoperative periods with higher corneal spherical aberration and corrected IOP at 3 months postoperatively. This trial is registered with ChiCTR-IOR-17013369.

Quantifying the effect of straylight on photopic contrast sensitivity.

The visual performance of a reference group (RG) using diffuser filters was compared to a cataract-diagnosed group (CatG). Measurements of straylight (SL) parameter, photopic contrast sensitivity (CS), and visual acuity (VA) were carried out in both groups. Before the analysis, the performance of the instruments used for this purpose was tested. The RG was comprised of three healthy, young eyes (25-30 years old) while 59 subjects (aged 50-80 years old) with lens opacities were recruited for the CatG. Six diffuser conditions were tested in the RG. To discriminate between light scattering levels, SL measurements proved to be most sensitive, VA did not discriminate at all, while CS showed intermediate sensitivity. VA was not correlated with SL, while the correlation between CS and SL was significant (p<0.05) in both groups. Since the correlation in the RG was particularly strong, parameters of a linear regression model are presented. The behavior of CS as a function of SL was comparable to some extent between RG and CatG.

Contrast sensitivity and visual acuity under low light conditions in macular telangiectasia type 2

Background/AimMacular pigment optical density (MPOD) is centrally depleted early on in macular telangiectasia type 2 (MacTel). Contrast sensitivity (CS) might be related to MPOD, and thus impaired in early MacTel....

Differential roles for cryptochromes in the mammalian retinal clock.

Cryptochromes 1 and 2 (CRY1/2) are key components of the negative limb of the mammalian circadian clock. Like many peripheral tissues, Cry1 and -2 are expressed in the retina, where they are thought to play a role in regulating rhythmic physiology. However, studies differ in consensus as to their localization and function, and CRY1 immunostaining has not been convincingly demonstrated in the retina. Here we describe the expression and function of CRY1 and -2 in the mouse retina in both sexes. Unexpectedly, we show that CRY1 is expressed throughout all retinal layers, whereas CRY2 is restricted to the photoreceptor layer. Retinal period 2::luciferase recordings from CRY1-deficient mice show reduced clock robustness and stability, while those from CRY2-deficient mice show normal, albeit long-period, rhythms. In functional studies, we then investigated well-defined rhythms in retinal physiology. Rhythms in the photopic electroretinogram, contrast sensitivity, and pupillary light response were all severely attenuated or abolished in CRY1-deficient mice. In contrast, these physiological rhythms are largely unaffected in mice lacking CRY2, and only photopic electroretinogram rhythms are affected. Together, our data suggest that CRY1 is an essential component of the mammalian retinal clock, whereas CRY2 has a more limited role.—Wong, J. C. Y., Smyllie, N. J., Banks, G. T., Pothecary, C. A., Barnard, A. R., Maywood, E. S., Jagannath, A., Hughes, S., van der Horst, G. T. J., MacLaren, R. E., Hankins, M. W., Hastings, M. H., Nolan, P. M., Foster, R. G., Peirson, S. N. Differential roles for cryptochromes in the mammalian retinal clock.

Visual outcome of penetrating keratoplasty, deep anterior lamellar keratoplasty and Descemet membrane endothelial keratoplasty

PurposeA single-center, cross-sectional study was designed to assess and compare objective and subjective quality of vision of patients intervened with penetrating keratoplasty (PK), deep anterior lamellar keratoplasty (DALK) and Descemet membrane endothelial keratoplasty (DMEK). MethodsForty-six patients previously intervened with PK (22 eyes), DALK (7 eyes) and DMEK (17 eyes) were recruited. Visual evaluation included spherical and cylindrical refraction, distance corrected visual acuity (DCVA), photopic contrast sensitivity (CS), optical quality, measured with the HD Analyzer (objective scattering index [OSI], MTF cut-off and Strehl ratio), and ocular and corneal aberrometry, measured with the KR-1W Wavefront Analyzer. ResultsStatistically significant between-group differences were found in age (p=0.006, DMEK patients were older) and time since surgery (p<0.001, longest time for PK patients). No statistically significant differences were found in DCVA between the techniques. Between-group differences were encountered in CS at 12 (p=0.007) and 18 (p<0.001) cycles per degree, with DMEK and DALK obtaining the best and worst outcomes, respectively. Differences in optical quality were found between the techniques (OSI, p=0.004; MTF cut-off, p=0.048; Strehl ratio p=0.022), with DMEK displaying the best outcomes. Highest and lowest values in ocular and corneal aberrations were for DALK and DMEK patients, respectively. Between-group differences were found in corneal astigmatism (p<0.001; −3.31±2.00 D in PK; −2.68±0.94 D in DALK; −1.09±0.62 D in DMEK). ConclusionOverall, DMEK proved superior over PK and DALK in terms of quality of vision, with PK offering slightly better outcomes than DALK in most visual function parameters under evaluation.

Depth of focus after implantation of spherical or aspheric intraocular lenses in hyperopic and emmetropic patients

To evaluate whether hyperopic patients with short axial length and high dioptric intraocular lens (IOL) power can achieve a higher depth of focus after implantation of a monofocal spherical or aspheric IOL than emmetropic patients. Department of Ophthalmology, Medical University Graz, Graz, Austria. Prospective case series. Patients presenting for cataract surgery were divided by calculated IOL power into a hyperopic (≥22.0 diopters [D]) or emmetropic (18.0 to 21.5 D) groups and received an aspheric (Tecnis ZA9003) or a spherical IOL (Sensar AR40e). Postoperative measurements included corrected (CDVA) and uncorrected (UDVA) distance visual acuities, distance-corrected intermediate (DCIVA) and near (DCNVA) visual acuities, root-mean-square values of corneal and total eye higher-order aberrations and spherical aberrations, and photopic and mesopic contrast sensitivity. Sixty-two eyes of 62 patients were enrolled in this study, 34 eyes (15 hyperopic, 19 emmetropic) in the aspheric IOL group and 28 eyes (14 hyperopic, 14 emmetropic) in the spherical IOL group. The UDVA, CDVA, and contrast sensitivity did not differ significantly between the 2 IOL groups, whereas the DCIVA and DCNVA were significantly better in the spherical IOL group (P=.004 and P=.001, respectively). No significant differences were found in DCIVA and DCNVA between hyperopic patients and emmetropic patients with aspheric or spherical IOLs. Implantation of a monofocal spherical IOL resulted in an increased depth of focus without significant degradation of distance visual acuity or contrast sensitivity. There were no differences in the depth of focus between hyperopic eyes and emmetropic eyes.

Normal upper age‐limits for photopic and mesopic visual acuity and functional contrast sensitivity

PurposeNormal, healthy aging causes a gradual worsening of vision with more pronounced effects at lower light levels (mesopic range). Normal spatial vision enables us to resolve fine spatial detail and to detect faint edges and boundaries that make up objects. Age‐related changes in the optics of the eye and diseases of the retina and / or systemic diseases that affect vision can also cause a loss of spatial vision. In order to separate the latter from the effects of normal aging, reliable, upper, normal limits of spatial vision are needed for both photopic and mesopic light levels. The purpose of this investigation was to measure visual acuity (VA) and functional contrast sensitivity (FCS) as a function of age in a large sample of normal subjects and to establish reliable, statistical limits to describe normal vision.Methods206 subjects (age range: 10‐77 years) have been investigated. A detailed medical and ocular history and eye examination were carried out. We measured photopic and mesopic VA and FCS in each subject under binocular and monocular viewing conditions with both positive and negative contrast using the Acuity‐Plus test (http://www.city.ac.uk/avot).ResultsThe best visual performance corresponds to ~ 15 to 35 years. The gradual increase in thresholds with increasing age was surprisingly small under all stimulus conditions below the fifth decade with significant differences between photopic and mesopic conditions.ConclusionsThresholds of VA and FCS increase gradually in normal aging. These preliminary results reveal a more pronounced effect between the fifth and sixth decade of life. On completion of this study, statistically‐reliable, upper, normal limits for VA and FCS will be determined as a function of age. These data will make it possible to detect reliable significant loss of spatial vision that cannot be attributed to normal aging.