Larger Pupil Diameter Research Articles

A comparison of small aperture implants providing increased depth of focus in pseudophakic eyes

Background and purposePresbyopia is characterized by a decreasing ability of accommodation – the eye's ability to alter the focus between far and near distance objects. After cataract surgery, accommodation is completely lost. Several years ago, small aperture (pinhole) implants have been presented in order to increase the depth of focus providing functional vision at far and near distance without the need for spectacles. We simulated the theoretical depth of focus with three different pseudophakic eye models in order to investigate the potential benefit arising from the implantation of small aperture optical (SAO) implants. The purpose was to compare the achievable defocus range of a SAO intraocular lens with a SAO corneal inlay. Material and methodsWe created three pseudophakic eye models with an aberration correcting intraocular lens (IOL): one with a corneal SAO implant (M1), a second one with a SAO intraocular lens (M2) and a third one with a conventional intraocular lens of the same optical design but without SAO (M0). Defocus curves were created by varying the focal length of a thin lens in front of the eye – which mimics the clinical assessment of defocus curves. ResultsWith a Strehl ratio threshold of 0.05, the reference design M0 provided a maximum defocus range of approximately 1.7D (with a 2.0mm pupil) whereas both pinhole implants (M1 and M2) showed a defocus range up to 3.0 and 3.3D, respectively. With large natural pupil diameter, where light passes outside the SAO aperture, the defocus range drops to 0.8D/0.7D for M1 and M2 compared to 0.7D with M0. ConclusionsThe SAO intraocular lens showed a similar defocus range as the SAO corneal inlay. Both concepts have the potential of increasing depth of focus compared to a conventional intraocular lens. In case of large physiological pupil diameters these advantages of SAO implants may be lost.

Can eye-tracking data be measured to assess product design?: Visual attention mechanism should be considered

Eye tracking probes user's perception of real-time reaction to products, while conventional methods (i.e. interviews, focus group, questionnaires and so on) have generally failed because they depend on users' willingness and competency to describe how they feel when they are exposed to a product. Two tasks were designed to explore the indexes of eye movement that can reflect user experience of product, and analyse the attention captured by product attributes and goal-oriented. In task one, participants just browsed two smart phone pictures and evaluated the whole user experience. Binary choices were used in task two to ask participants to select the smart phone picture with higher user experience and then click the mouse. The results showed that in the browsing task, participants had shorter time to first fixation for the smart phone picture with higher level of user experience than the lower. And pupil dilated significantly when participants browse smart phone picture with lower level of user experience. In goal-oriented task, participants' attentions were dominated by visual perception of task driven, mainly reflected on longer fixation time and larger pupil diameter when looking at the smart phone with higher level of user experience. These results support the notion that we cannot assess product design just by several eye-movement indexes without considering the effects of visual attention mechanism. Relevance to industryThe appearance of product plays an important role to attract user's attention and stimulate their intention to experience. And vision is the main channel for users to obtain product information. Hence a thorough research on the inherent mechanism of vision perception can provide technical support for product designers, which in turn can attract more consumers to experience the product, even buy it. Moreover, the seller can find out the real buyers and predict their desired products by tracking user's eyes.

Comparison of the Optical Quality between Small Incision Lenticule Extraction and Femtosecond Laser LASIK.

Purpose. To investigate the visual quality after SMILE and Femto-LASIK. Methods. About 123 eyes from 63 patients were enrolled in this study. The parameters were measured preoperatively and 1 week, 1 month, and 3 months postoperatively using Sirius System. Results. The MTF curve increase slightly from low to high frequency at 3 mm and 6 mm pupil diameter after SMILE surgery (P < 0.05) during the follow-up time comparing with the preoperative values. And the SR has a significant increase at various pupil diameters as well (P < 0.05). However, there was little increase for MTF at intermediate to high frequency at 3 mm pupil diameter after Femto-LASIK procedure (P < 0.05). And the SR had only significant increase at 3 mm pupil diameter. Between SMILE and Femto-LASIK, there was no statistic difference both in MTF and SR (P > 0.05) at 3 mm pupil diameter at vertical and horizontal meridian. However, significant difference was found in MTF at low to mediate frequency at 6 mm pupil diameter at vertical meridian at 1 week postoperatively (P < 0.05). Conclusions. Both SMILE and Femto-LASIK show a great improvement in optical quality at small diameter. It was found that SMILE shows better optical quality than Femto-LASIK at larger pupil diameter, which might be good for the night vision.

Optical quality comparison between 2 collagen copolymer posterior chamber phakic intraocular lens designs

To compare the optical quality in vitro of 2 designs of the Visian Implantable Collamer Lens phakic intraocular lens (pIOL) for different powers and optical apertures. University of Valencia, Valencia, Spain. Experimental study. The Nimo TR1504 deflectometry device was used to measure the V4c pIOL, which has a smaller optic diameter, and the V5 pIOL, which has a larger optic diameter. The pIOLs were measured for -3.00 diopters (D), -6.00 D, -9.50 D, and -10.50 D at different optical apertures from 3.00 to 6.00 mm depending on the IOL power and model. The root mean square of higher-order aberrations (RMS HOAs) was analyzed. The Strehl ratio, point-spread functions (PSFs), and simulated images were calculated from wavefront aberrations. There were no statistically significant differences in any Zernike RMS or RMS HOAs between the 2 pIOL models with the same power and optical aperture (P > .05). Both pIOLs had negative spherical aberration that increased with the pIOL power. Strehl ratio values showed no statistically significant differences between the pIOLs with the same power and pupil aperture. Minimal differences were seen in the PSFs and simulated images between the pIOLs. Both pIOLs showed good and comparable in vitro optical quality similar that of a perfect lens in that they should not affect visual performance after implantation. Patients with larger pupil diameters could benefit from the pIOL with the larger optic diameter because it showed better in vitro optical quality than the previous design with a smaller optic diameter. No author has a financial or proprietary interest in any material or method mentioned.

Quantitative analysis of iris changes after physiologic and pharmacologic mydriasis in a rural Chinese population.

To estimate and compare the change in iris cross-sectional area (IA) and iris volume (IV) following physiologic and pharmacologic pupil dilation in primary angle closure suspects (PACS) and normal subjects. Anterior segment-optical coherence tomography (AS-OCT) measurements in light, dark, and following pharmacologic dilation were obtained on 186 PACS and 224 normal subjects examined during the 5-year follow-up of the Handan Eye Study. Iris cross-sectional area, IV, and other biometric parameters calculated using the Zhongshan angle assessment program in the right eyes of all subjects were analyzed. The mean IA and IV decreased in dark compared with light and after pharmacologic dilation in both PACS and normal eyes. This change was statistically significant in normal eyes: light versus pharmacologic dilation for IA (P = 0.038) and for IV, both light versus dark (P = 0.031) and light versus pharmacologic dilation (P = 0.012). A longer axial length (P = 0.028) and a greater change in pupil diameter (PD) (P < 0.001) were associated with a larger decrease of IA for the light to dark comparison. A diagnosis of normal eyes (P = 0.011), larger PD in dark (P = 0.001), and a larger change in PD (P = 0.001) were associated with a larger decrease of IV from light to dark. The differences in iris behavior between PACS and normal rural Chinese subjects following physiologic or pharmacologic pupillary dilation may help provide insights into the pathogenesis of angle closure.

Portrait hemispheric laterality measured using pupil diameter and aesthetic judgments.

Eckhard Hess’s claim that pupils dilate to pleasant images and constrict to unpleasant images was confounded because of inconsistent contrasts and luminances across his images. Building upon the work of Powell and Schirillo (2011) that explored multiple portraits by Rembrandt, we offer a new and promising methodology that overcomes this limitation. We presented leftward- or rightward-facing female and male portraits by 12 artists from various epochs to observers in either their original or mirror-reversed positions. Simultaneously, we asked observers to report how (dis)pleasing they found each image while measuring their pupil size. We found that pupil diameter was a function of arousal only while viewing male portraits. That is, for male images rated both low and high in pleasantness, larger pupil diameters were obtained. We postulate that our findings may be the result of the perceived dominance of males and how hemispheric laterality may drive emotional expression.

Optical design of a near-infrared imaging spectropolarimeter for the Advanced Technology Solar Telescope

In designing the optics of an imaging multi-etalon spectropolarimeter as a post-focus instrument for the Advanced Technology Solar Telescope (ATST), many constraints must be considered. Among these are the large entrance pupil diameter of the telescope (4 m), the demanded large field of view (≥90 arc sec ), high spectral resolving power (≥200,000 ), and limited field-dependent blue-shift of the instrumental profile [≤3 full width at half maximum (FWHM)], which require Fabry-Perot interferometers of large diameter (≥200 mm ), lighted by highly collimated beams. This implies large optical elements and long optical paths. Moreover, to use interference pre-filters with a relatively small diameter (≤70 mm ) and placed between the interferometers to reduce the inter-reflections in axial-mount, a “pupil adapter” must be included with a further increase of the optical path length. Although a multi-etalon spectropolarimeter works in quasi-monochromatic light, the Fraunhofer lines of interest cover a wide range of wavelengths (850 to 1650 nm), which demands a good chromatic aberration control. A low instrumental polarization (≤0.5% ) is also required to allow a high polarimetric precision. Finally, some secondary optical paths are required to perform the initial instrumental setup and to secure the best instrumental performances. A diffraction-limited optical solution for ATST is described that fulfills all the above requirements in a relative small volume.

The “subjective” pupil old/new effect: Is the truth plain to see?

Human memory is an imperfect process, prone to distortion and errors that range from minor disturbances to major errors that can have serious consequences on everyday life. In this study, we investigated false remembering of manipulatory verbs using an explicit recognition task and pupillometry. Our results replicated the “classical” pupil old/new effect as well as data in false remembering literature that show how items must be recognize as old in order for the pupil size to increase (e.g., “subjective” pupil old/new effect), even though these items do not necessarily have to be truly old. These findings support the strength-of-memory trace account that affirms that pupil dilation is related to experience rather than to the accuracy of recognition. Moreover, behavioral results showed higher rates of true and false recognitions for manipulatory verbs and a consequent larger pupil diameter, supporting the embodied view of language.

Effect of Pupil Size on Uncorrected Visual Acuity in Pseudophakic Eyes With Astigmatism

To study the effect of pupil size on the relationship between refractive astigmatism and uncorrected distance visual acuity (UDVA) and pseudoaccommodation in pseudophakic eyes. Thirty-six eyes from 36 patients who underwent phacoemulsification and intraocular lens (IOL) implantation were included. All eyes were divided into two groups based on the presence of postoperative-with-the-rule astigmatism or against-the-rule astigmatism. Uncorrected and corrected distance visual acuity (CDVA), refractive astigmatism, subjective accommodation amplitude, and pupil sizes under photopic and mesopic conditions were measured 1 month postoperatively. The effects of pupil size on the relationship between refractive astigmatism and UDVA were investigated. Against-the-rule astigmatism had a moderate but significant negative linear correlation with UDVA irrespective of the pupil size (R(2)=0.60, P<.01). A moderate but significant negative linear correlation was found when the pupil diameter exceeded 2.9 mm in eyes with with-the-rule astigmatism (R(2)=0.46, P=.04). Refractive astigmatism was not significantly correlated with pseudoaccommodation regardless of the pupil diameter in either group. The results of the current study suggest that pupil size may have an impact on postoperative UDVA in eyes having against-the-rule astigmatism and in eyes with a large pupil diameter and with-the-rule astigmatism.

Impact of Pupil Diameter on Axial Growth in Orthokeratology

To compare axial elongation between myopic orthokeratology (OK) contact lens and spectacle wearers, and to investigate the impact of pupil diameter on axial growth in myopic children after OK treatment. Fifty-two Chinese children aged 9 to 14 years were enrolled in this study, 27 for the OK group and 25 for the single vision spectacle lenses (SVL) group. Subjects in each group were further divided into two subcategories according to their baseline scotopic pupil diameters. Axial length (AL) was measured at baseline and at every 6-month visit through to 24 months. Linear mixed-effect model was used to determine myopia progression (AL changes from baseline). In this model, repeated visits were taken as within-subject effect, and treatment group as well as pupil size were taken as between-subject effects. The interaction of treatment group*pupil size was analyzed. Relationships between axial growth at 24 months and baseline pupil area were analyzed in both lens groups. Twenty-five subjects in the OK group and 22 subjects in the SVL group completed the 24-month study. AL increased significantly throughout the observed 24-month period (F = 32.09, p < 0.001). Pupil size significantly affected axial growth (F = 15.95, p < 0.001) and different treatment modalities (OK vs. SVL) interacted with the effect of pupil size on axial growth (F = 24.66, p < 0.001). To be more specific, axial growth was significantly slower in subjects with above average pupil sizes than those with below average pupil sizes in the OK group (F = 25.04, p < 0.001). Contrarily, pupil size did not affect axial growth in the SVL group (F = 0.46, p = 0.50). Baseline scotopic pupil area was significantly correlated to axial growth in the OK group (r = 0.405, p < 0.001) but not in the SVL group (r = 0.171, p = 0.056). Large pupil diameters facilitate the effect of OK to slow axial growth in myopia. We speculate that this is because of enhancement of the myopic shift in the peripheral retina.

Residual Astigmatism Following Toric Intraocular Lens Implantation Related to Pupil Size

To present two patients with residual astigmatism following toric intraocular lens (IOL) implantation. Case reports. A 58-year-old woman underwent toric IOL implantation (spherical power 29.50 diopters [D], cylinder power 3.00 D; SN60T5, Alcon Laboratories Inc) to correct 2.33 D @ 80° of corneal astigmatism. Postoperatively, uncorrected distance visual acuity (UDVA) was 20/30 and corrected distance visual acuity (CDVA) was 20/22 (0 -1.75 × 95), indicating an overcorrection of astigmatism. Slit-lamp examination demonstrated no IOL misalignment. Wavefront aberrometry showed a large pupil diameter (>6 mm) and a lower corneal astigmatism in a 6-mm zone (-1.40 D @ 174°) compared to a 4-mm zone (-2.21 D @ 171°). The second patient, a 60-year-old man, underwent multifocal toric IOL implantation (spherical power 22.50 D, cylinder power 2.25 D; SND1T4, Alcon Laboratories Inc) to correct 1.51 D @ 173° of corneal astigmatism. Postoperatively, UDVA was 20/50 and CDVA was 20/20 (+0.25 -1.00 × 102), indicating an undercorrection of astigmatism. Slit-lamp examination showed no misalignment. Both cases indicate that unexplained residual astigmatism following toric IOL implantation may be the result of multiple factors: the effect of the spherical power and anterior chamber depth on toric IOL calculations, the effect of posterior corneal astigmatism, and the effect of a large pupil size. The first two issues may be compensated for by improving toric IOL calculations. The latter indicates that pupillometry is indicated in relatively young patients who undergo toric IOL implantation.

Ocular Axial Length and Its Associations in Chinese: The Beijing Eye Study

PurposeTo investigate the normative data of ocular axial length and its associations in Chinese.MethodThe population-based Beijing Eye Study 2011 is a cross-sectional study performed in Greater Beijing. The study included 3468 individuals (1963 (56.6%) women) with a mean age of 64.6±9.8 years (range: 50–93 years). A detailed ophthalmic and medical examination was performed. Axial length was measured by optical low-coherence reflectometry.ResultsAxial length measurements were available for 3159 (91.1%) study participants. Mean axial length was 23.25±1.14 mm (range: 18.96–30.88 mm). In multivariate analysis, axial length was significantly associated with the systemic parameters of higher age (P<0.001), higher body height (P = 0.003), higher level of education (P<0.001) and urban region of habitation (P<0.001), and with the ocular parameters of thicker central cornea (P = 0.001), higher corneal curvature radius (P<0.001), deeper anterior chamber (P<0.001), thicker lens (P<0.001), more myopic refractive error (P<0.001), larger pupil diameter (P = 0.018), and higher best corrected visual acuity (P<0.001). It was additionally and negatively associated with the lens vault (P<0.001). In highly myopic eyes, axial length was significantly associated with lower level of education (P = 0.008), more myopic refractive error (P<0.001), and lower best corrected visual acuity (P = 0.034).ConclusionsMean ocular axial length in the older adult population of Greater Beijing (23.25±1.14 mm) was similar to the value measured in other urban populations and was higher than in a rural Central Indian population. The association between axial length and older age may potentially be associated with a survival artifact. The association between axial length and body height agrees with the general association between anthropomorphic measures and eye globe size. The association with the level of education and urban region of habitation confirms with previous studies. In contrast in highly myopic eyes, axial length was negatively associated with educational level and best corrected visual acuity.

Ray-tracing analysis of intraocular lens power in situ

To describe a method for back-solving the power of an intraocular lens (IOL) in situ based on laser biometry and ray-tracing analysis of the pseudophakic eye. University Eye Clinic, Aarhus Hospital, Aarhus, Denmark. Evaluation of diagnostic test or technology. This study comprised pseudophakic eyes with an IOL power ranging from -2.00 to +36.00 diopters (D). Preoperatively, the corneal radius was measured with conventional autokeratometry and the axial length (AL) with optical biometry. After surgery, the position of the IOL was recorded using laser interferometry. Based on the postoperative refraction and the biometric measurements, a ray-tracing analysis was performed back-solving for the power of the IOL in situ. The analysis was performed assuming pupil diameters from 0.0 to 8.0 mm with and without correction for the Stiles-Crawford effect. The study evaluated 767 pseudophakic eyes (583 patients). Assuming a 3.0 mm pupil, the mean prediction error between the labeled and the calculated IOL power (± 1 standard deviation [SD]) was -0.26 D ± 0.65 (SD) (range -2.4 to +1.8 D). The prediction error showed no bias with IOL power or with AL. The calculated IOL power depended on the assumed pupil size and the Stiles-Crawford effect. However, the latter had a modulatory effect on the prediction error for large pupil diameters (>5.0 mm) only. The optics of the pseudophakic eye can be accurately described using exact ray tracing and modern biometric techniques.

Visual outcome after correcting the refractive error of large pupil patients with wavefront-guided ablation

PurposeTo investigate the efficacy and predictability of wavefront-guided laser in situ keratomileusis (LASIK) treatments using the iris registration (IR) technology for the correction of refractive errors in patients with large pupils.SettingHorus Vision Correction Center, Alexandria, Egypt.MethodsProspective noncomparative study including a total of 52 eyes of 30 consecutive laser refractive correction candidates with large mesopic pupil diameters and myopia or myopic astigmatism. Wavefront-guided LASIK was performed in all cases using the VISX STAR S4 IR excimer laser platform. Visual, refractive, aberrometric and mesopic contrast sensitivity (CS) outcomes were evaluated during a 6-month follow-up.ResultsMean mesopic pupil diameter ranged from 8.0 mm to 9.4 mm. A significant improvement in uncorrected distance visual acuity (UCDVA) (P < 0.01) was found postoperatively, which was consistent with a significant refractive correction (P < 0.01). No significant change was detected in corrected distance visual acuity (CDVA) (P = 0.11). Efficacy index (the ratio of postoperative UCDVA to preoperative CDVA) and safety index (the ratio of postoperative CDVA to preoperative CDVA) were calculated. Mean efficacy and safety indices were 1.06 ± 0.33 and 1.05 ± 0.18, respectively, and 92.31% of eyes had a postoperative spherical equivalent within ±0.50 diopters (D). Manifest refractive spherical equivalent improved significantly (P < 0.05) from a preoperative level of −3.1 ± 1.6 D (range −6.6 to 0 D) to −0.1 ± 0.2 D (range −1.3 to 0.1 D) at 6 months postoperative. No significant changes were found in mesopic CS (P ≥ 0.08), except CS for three cycles/degree, which improved significantly (P = 0.02). Magnitudes of primary coma and trefoil did not change significantly (P ≥ 0.34), with a small but statistically significant increase in primary spherical aberration.ConclusionWavefront-guided LASIK provides an effective correction of low to moderate myopia or myopic astigmatism in large pupil patients without deterioration of visual quality.

Individual Differences in Face Processing: Infants' Scanning Patterns and Pupil Dilations are Influenced by the Distribution of Parental Leave.

Fourteen-month-old infants were presented with static images of happy, neutral, and fearful emotional facial expressions in an eye-tracking paradigm. The emotions were expressed by the infant's own parents as well as a male and female stranger (parents of another participating infant). Rather than measuring the duration of gaze in particular areas of interest, we measured number of fixations, distribution of fixations, and pupil diameter to evaluate global scanning patterns and reactions to emotional content. The three measures were differentially sensitive to differences in parental leave, emotional expression, and face familiarity. Infants scanned and processed differently happy, neutral, and fearful faces. In addition, infants cared for by both father and mother (divided parental leave) distributed their gaze more across faces than did infants primarily cared for by one parent (in this study, the mother). Pupil diameter complemented these findings, revealing that infants had larger pupil diameter during observation of neutral emotions expressed by the parent who is not currently the primary caregiver. This study demonstrates how conclusions differ as a function of the particular eye-tracking measure used and shows that the three measures used here converge on the conclusion that 14-month-old infants' processing of emotional expressions is influenced by infants' exposure to fathers and mothers.

Hemispheric laterality measured in Rembrandt's portraits using pupil diameter and aesthetic verbal judgements

Eckhard Hess claimed that pupils dilate to pleasant images and constrict to unpleasant images. However, his work was confounded since his image's luminances and contrasts across conditions were inconsistent. We overcome this limitation and suggest a new, promising methodology for research in this area. We presented rightward or leftward facing male and female portraits by Rembrandt to observers in either their original or mirror-reversed position. Since emotional content may be expressed differently on each side of the face, we used Rembrandt's portraits since most of his males had their right-cheek exposed and females had their left-cheek exposed. This raises questions regarding the emotional and cognitive significance of such biased positioning. Simultaneously, we measured observers pupil size while asking observers to report how (dis)pleasing they found each image. We found that in viewing male portraits pupil diameter was a function of arousal. That is, larger pupil diameter occurred for images rated both low and high in pleasantness. We discuss these findings in regard to the perceived dominance of males and how emotional expressions may be driven by hemispheric laterality.

Surgical options with narrow pupil and floppy iris syndrome

The main reasons for encountering small pupils during cataract surgery are well established. They include cases with pseudoexfoliation syndrome, uveitis, posterior synechiae. Campbell have described the intraoperative floppy-iris syndrome (IFIS) associated with systemic administration of the α-1A antagonist tamsulosin (Flomax). The intraoperative diagnostic triad of this symptom is fluttering and billowing of the iris stroma, a tendency to iris prolapse through the main and/or sideport incisions, and progressive constriction of the pupil during surgery. Unfortunately, current pharmacological approaches for managing a small pupil during cataract surgery have limitations. Patients whose pupils respond poorly to the pharmacological protocols present significant challenges. The most significant problems for the surgeon are decreased visualization, iris trauma due to incarceration into the wound, iris chafing, pupillary margin damage by the phaco needle and others. All of these problems compromise the surgery and increase the risk for complications. There is no general recommendation or solution to the small pupil problem because the strategies for pupil enlargement greatly depend on surgeon skill and preferences, as well as on intraoperative situation. Most surgeons decide to dilate the pupil mechanically at the time of the surgery if pharmacological agents fail. There are four main mechanical dilation methods: synechiolysis, mechanical stretching, cutting of the iris tissue and iris retraction. Most of the surgical maneuvers for enlarging the pupil and preventing its intraoperative constriction are not safe enough. They can lead to an increased risk of iris sphincter tear, bleeding, iris damage, posterior capsule tears and loss of the vitreous body. But not all patients require pupil dilation protocols with the mechanical devices. If the iris tissue is rigid and the diameter of the pupil is about 4.0mm to 4.5mm, an experienced surgeon, especially when using different modifications of phaco-chop technique, can effectively remove cataract and avoid significant trauma of the anterior segment tissues. Conversely, if the iris tissue is flaccid and atonic, even if the pupil is reasonably wide, such as with IFIS, there is a significant risk of complications. The postoperative complications can include an atonic pupil of irregular shape with poor cosmetic result and photophobia. One of the newest devices to enlarge the small pupil during phacoemulsification is the Malyugin Ring utilizing the scroll principle of catching the papillary margin (Figure 1). Malyugin Ring System consisting of a sterile single-use inserter and holder. The dark blue Ring is located inside the holder and can be visualized through its upper portion. It can be used with conventional SICS (Small Incision Cataract Surgery) as well as MICS (Microincision Cataract Surgery). The newest version – the 7.0-mm Malyugin Ring produced by MST provides a larger pupil diameter compared to the conventional 6.25-mm ring. 7.0 Ring handles IFIS cases more easily. When the iris is very flaccid but the pupil is wide, the 6.25mm Ring can be dislocated at one or two scrolls and would need to be repositioned. This does not happen with the larger-size Ring. Advantages of the Malyugin Ring: Adequate transpupillary access to the lens is essential for the success of phaco procedures. We believe that our irisretraction technique with the Malyugin Ring System has at least six distinct advantages: Summary: Different techniques of nucleus disassembly in small-incision cataract surgery require a wide and unobstructed view of the anterior portion of the lens, as well as of the instruments inserted into the anterior chamber. The other important factor is sufficient manipulability of the instruments, which is critical for the successful completion of surgery. A pupil that fails to dilate makes cataract removal more difficult. The Malyugin Ring adequately dilates the pupil and prevents iris sphincter damage. The ease of inserting and removing the device expands the pupil, protects the iris sphincter during surgery, and allows the pupil to return to its normal shape, size and function after the operation. Careful intraoperative manipulation and insertion of the Ring, with liberal use of an ophthalmic viscoelastic device, helps to prevent complications. Most of our postop patients had pupils almost indistinguishable in appearance than before surgery and functional activity was preserved. This is among the most effective methods to increase the size of even very rigid small pupils during phacoemulsification abnormalities in pupil size and function.

Optical Coherence Tomography Quantitative Analysis of Iris Volume Changes after Pharmacologic Mydriasis

To describe a method using anterior segment optical coherence tomography (AS OCT) for estimating iris volume. To quantify changes in iris volume induced by pharmacologic mydriasis in narrow-angle eyes predisposed to angle-closure compared with normal open-angle eyes. Cross-sectional study. Thirty fellow eyes of 30 patients who had an episode of primary acute angle-closure and 30 eyes of 30 normal age- and gender-matched subjects with open angles. All fellow eyes had a patent laser peripheral iridotomy. Iris volume and all biometric measurements were performed before and after instillation of 1% tropicamide and at least 1 week later 10% phenylephrine. Iris volume was estimated using AS OCT radial sections of the iris and a customized image-processing software. Iris volume, pupil diameter, angle configuration including angle opening distance at 500 mum (AOD 500) and trabecular-iris space at 500 mum (TISA 500), AS OCT anterior chamber depth, and A-scan ultrasonography axial length before and after pupil dilation. Iris volumes measured before dilation of the pupil were 44.94+/-2.1 mm(3) and 44.29+/-3.9 mm(3) in the fellow eyes and open-angle eyes, respectively, which was not significantly different (P>0.1). Thirty minutes after instillation of 1% tropicamide, mean iris volume increased significantly in the fellow eyes (from 44.94+/-2.1 mm(3) to 49.92+/-2.9 mm(3); P<0.01), whereas it decreased significantly in the open-angle eyes (from 44.29+/-3.9 mm(3) to 37.88+/-2.2 mm(3); P<0.01). Similar changes were observed after instillation of 10% phenylephrine. Based on multivariate analysis, significant predictors of increase in iris volume after pupil dilation were eyes predisposed to angle-closure compared with open-angle eyes (P = 0.008), larger pupil diameter (P = 0.02), and brown eyes (P = 0.01). Relative iris volume increase was correlated significantly with AOD 500 and TISA 500 relative decrease in the narrow-angle group (P<0.05). The iris volume may be estimated with AS OCT. The iris volume increases after pupil dilation in narrow-angle eyes predisposed to acute angle closure. In those patients, this biometric change is associated with a narrowing of the angle despite a patent laser peripheral iridotomy. The author(s) have no proprietary or commercial interest in any materials discussed in this article.

Iris Cross-sectional Area Decreases With Pupil Dilation and its Dynamic Behavior is a Risk Factor in Angle Closure

To estimate the change in iris cross-sectional (CS) area with pupil dilation using anterior segment optical coherence tomography comparing eyes with angle closure (AC) to open angle glaucoma (OAG). Sixty-five patients from the Wilmer Glaucoma service, 36 with definite or suspected OAG and 29 with definite or suspected AC, underwent anterior segment optical coherence tomography imaging under 3 conditions (pupil constriction to light, physiologic dilation in the dark, and after pharmacologic dilation). The nasal and temporal iris CS areas were measured with custom software, 3 times in each of 4 meridians. The principal outcome variables were iris CS area and change in iris CS area/mm pupil diameter change. The relation of these parameters to potential variables that would influence iris area was estimated by multivariate regression. CS area was smaller in eyes with larger pupil diameter, those that had undergone trabeculectomy, and those of European-derived persons (P<0.05 for all in a univariate analysis). In a multivariate model with CS area as the dependent variable, larger pupil diameter (with a 0.19 mm decrease in CS area for each 1 mm of pupil enlargement, P=0.0002), and trabeculectomy remained significant factors. In a second multivariate model, AC irides had less change in CS area/mm pupil enlargement than OAG or OAG suspects (P=0.01). Change in iris CS area was essentially complete in 5 seconds (n=10 eyes). The iris loses nearly half its volume from a pupil diameter of 3 to 7 mm, probably by eliminating extracellular fluid. Smaller iris CS area change with physiologic pupil dilation is a potential risk factor for AC. Dynamic iris CS area change deserves testing as a prospective indicator of AC.

Serotonin Transporter Genotype Modulates Social Reward and Punishment in Rhesus Macaques

BackgroundSerotonin signaling influences social behavior in both human and nonhuman primates. In humans, variation upstream of the promoter region of the serotonin transporter gene (5-HTTLPR) has recently been shown to influence both behavioral measures of social anxiety and amygdala response to social threats. Here we show that length polymorphisms in 5-HTTLPR predict social reward and punishment in rhesus macaques, a species in which 5-HTTLPR variation is analogous to that of humans.Methodology/Principal FindingsIn contrast to monkeys with two copies of the long allele (L/L), monkeys with one copy of the short allele of this gene (S/L) spent less time gazing at face than non-face images, less time looking in the eye region of faces, and had larger pupil diameters when gazing at photos of a high versus low status male macaques. Moreover, in a novel primed gambling task, presentation of photos of high status male macaques promoted risk-aversion in S/L monkeys but promoted risk-seeking in L/L monkeys. Finally, as measured by a “pay-per-view” task, S/L monkeys required juice payment to view photos of high status males, whereas L/L monkeys sacrificed fluid to see the same photos.Conclusions/SignificanceThese data indicate that genetic variation in serotonin function contributes to social reward and punishment in rhesus macaques, and thus shapes social behavior in humans and rhesus macaques alike.