Pupil Shape Research Articles

Random phase plate designed by the genetic algorithm for decoherence in energy homogenization units of a photolithography illumination system

The microlens array (MLA) is used in the flexible pupil shaping module of lithography illumination system for energy balance. However, the coherence of the light source can lead to interference patterns. Most of the decoherence methods are restricted for the pulse laser and the scanning exposure application. To solve this issue, a specific random phase plate (RPP) is designed to eliminate the interference patterns caused by the coherence of the light source. The model of partially coherent light propagation in the MLAs homogeneous system is established based on the mutual intensity theory, and the genetic algorithm is introduced to design a high-performance RPP. The corresponding measurement device is constructed, and the intensity of the image plane light field is measured. Experiment results indicate that the intensity integral non-uniformity is 32.14% in the x-direction and 66.04% in the y-direction without the RPP, and the intensity integral non-uniformity is 22.95% in the x-direction and 19.18% in the y-direction with the RPP, which verifies the feasibility of the proposed method.

Enhanced single-frame interferometry via hybrid conv-transformer architecture for ultra-precise phase retrieval

Precise dynamic single-frame interferometry based on virtual phase shifting technique remains challenging due to the difficulty in satisfying the requirements for the quality and amount of fine-grained fringe’s interferograms. Here we introduce a novel deep learning architecture, the Transformer Encoder-Convolution Decoder Phase Shift Network (TECD-PSNet), that achieves high-fidelity interferogram reconstruction. TECD-PSNet seamlessly integrates the strengths of transformer blocks in capturing global descriptions and convolution blocks in efficient feature extraction. A key process is the incorporation of a residual local negative feedback enhancement mechanism that adaptively amplifies losses in high-error regions to boost fine-grained detail sensitivity. This approach enables accurate phase retrieval for diverse pupil shapes, enhancing adaptability to various optical setups, while significantly reducing the amount of training data required. Experiments demonstrate a 22.9% improvement in PSNR for reconstructed interferograms and a 36.7% reduction in RMS error for retrieved phases compared to state-of-the-art methods.

Diversity and Molecular Evolution of Nonvisual Opsin Genes across Environmental, Developmental, and Morphological Adaptations in Frogs.

Nonvisual opsins are transmembrane proteins expressed in the eyes and other tissues of many animals. When paired with a light-sensitive chromophore, nonvisual opsins form photopigments involved in various nonvisual, light-detection functions including circadian rhythm regulation, light-seeking behaviors, and seasonal responses. Here, we investigate the molecular evolution of nonvisual opsin genes in anuran amphibians (frogs and toads). We test several evolutionary hypotheses including the predicted loss of nonvisual opsins due to nocturnal ancestry and potential functional differences in nonvisual opsins resulting from environmental light variation across diverse anuran ecologies. Using whole-eye transcriptomes of 81 species, combined with genomes, multitissue transcriptomes, and independently annotated genes from an additional 21 species, we identify which nonvisual opsins are present in anuran genomes and those that are also expressed in the eyes, compare selective constraint among genes, and test for potential adaptive evolution by comparing selection between discrete ecological classes. At the genomic level, we recovered all 18 ancestral vertebrate nonvisual opsins, indicating that anurans demonstrate the lowest documented amount of opsin gene loss among ancestrally nocturnal tetrapods. We consistently found expression of 14 nonvisual opsins in anuran eyes and detected positive selection in a subset of these genes. We also found shifts in selective constraint acting on nonvisual opsins in frogs with differing activity periods, habitats, distributions, life histories, and pupil shapes, which may reflect functional adaptation. Although many nonvisual opsins remain poorly understood, these findings provide insight into the diversity and evolution of these genes across anurans, filling an important gap in our understanding of vertebrate opsins and setting the stage for future research on their functional evolution across taxa.

Pupil Data Upon Stimulation by Auditory Stimuli

Evaluating hearing in newborns and uncooperative patients can pose a considerable challenge. One potential solution might be to employ the Pupil Dilation Response (PDR) as an objective physiological metric. In this dataset descriptor paper, we present a collection of data showing changes in pupil dimension and shape upon presentation of auditory stimuli. In particular, we collected pupil data from 16 subjects, with no known hearing loss, upon different lighting conditions, measured in response to a series of 60–100 audible tones, all of the same frequency and amplitude, which may serve to further investigate any relationship between hearing capabilities and PDRs.

Challanges Prepupillary Iris Claw Implantation In Irregular-Shaped Pupil

Introduction : For decades secondary implants carry a greater risk of high complications. The iris claw technique is popular because of the safe and fast IOL implantation. But, in this case there is a difficulty where the pupil shape is irregular so that it is a challenge for enclavation the haptic on the prepupillary iris.
 Case Illustration : A man, 39 YO, came with complaints of blurred right eye after surgery on the right eye 6 months ago. Vision 1/60 with pinhole reaching 20/70, , deep anterior chamber with VH 4, positive iris tremulans, with irregular shape in temporal regio where is the main port where the first operation was performed, not centrally located pupil. There was no intraocular lens found in the lens. The patient was planned for the installation of a Secondary IOL in the right eye with a prepupillary iris claw and endodiathermal pupilloplasty to returns the pupil to the central position. One day after surgery, visual acuity was 1/300, IOP was 30 mmHg and the descment fold. The anterior chamber is difficult to evaluate. 4 weeks after surgery, Vision was 20/70, cornea was clear and IOP was 17mmHg without the need for return surgery.
 Discussion : Until now, there is still no consensus regarding the best management options to correct aphakia without adequate lens capsule support. Endothermal diathermy pupilloplasty itself aims to create and maintain an appropriate pupil size.
 Conclusion : Even though there are complications, the installation of the iris claw on the prepupillary is still a safe technique for aphakic correction.

Optimization of Pupil Fit Parameters for Contact Hole Pattern CD Difference Improvement

AbstractIn the stacked semiconductor structure, the contact hole layer is widely used in Dram/3D NAND as a connection path between layers. During the lithographical process of the contact hole layer, a critical issue known as CD difference appears. When faced with this issue in a mass production environment, solutions are limited. In particular, the only solution for the issue caused by a difference of pupil shape is to change the illumination ID, which requires a full design change of the pupil. This is challenging and causes differences in the recipe and equipment. As a way to fundamentally solve this problem, the ellipticity among the pupil fit parameters is optimized to minimize CD differences. Through simulation, the difference between the issue pupil and the reference pupil was confirmed, and the pupil fit parameter was calculated. The pupil shape was predicted by applying the calculated pupil fit parameter. Pattern simulation was performed using the predicted pupil shape, and conditions suitable for the direction of improvement were established to confirm improved CD difference. In both cases, the improvement tendency was confirmed in the predicted direction and was suitable for a mass production environment.

Diagnosis of lymphoma based on magnetic resonance imaging, analysis of cerebrospinal fluid, intraocular fluid and fine‐needle aspirate of a uveal mass lesion in a dog

AbstractA 10.5‐year‐old, male, entire labrador retriever dog was presented for chronic progressive ataxia and recent onset of a left‐sided head tilt and salivation. Neurological examination findings were deemed consistent with a multifocal brain and spinal cord neuroanatomic localisation. Ophthalmological examination of the right eye revealed pupil shape abnormality (dyscoria), a pale uveal mass lesion and white cellular sediment in the anterior chamber. Magnetic resonance imaging of the brain, eyes, thoracolumbar and lumbosacral spinal cord and surrounding structures showed multiple lesions affecting the central nervous system (brain), peripheral nervous system (left trigeminal nerve) and right eye. Cerebrospinal fluid, right eye anterior chamber fluid and fine‐needle aspirate biopsy of the uveal mass lesion yielded a cytological diagnosis of lymphoma (suspected large granular lymphocytic). The dog was discharged with palliative treatment and euthanased at home 4 days later. This case report documents the cytological diagnosis of lymphoma in the cerebrospinal fluid, intraocular fluid and fine‐needle aspirate of a uveal mass in a dog.

Sutureless intrascleral intraocular lens fixation and modified iris cerclage pupilloplasty for aphakia and traumatic mydriasis.

To evaluate the safety and efficacy of sutureless intrascleral intraocular lens (IOL) fixation combined with modified iris cerclage pupilloplasty for treating aphakia and traumatic mydriasis. Five patients with aphakia and traumatic mydriasis were operated on by the same surgeon. All patients underwent sutureless intrascleral IOL fixation combined with modified iris cerclage pupilloplasty and were followed up for ≥6 months. Best-corrected visual acuity (BCVA) was measured using the logarithm of the minimum angle of resolution (logMAR). BCVA, intraocular pressure (IOP), pupil diameter, and corneal endothelial cell count (CECC) preoperatively and postoperatively were statistically analyzed. The pupil shape, photophobia, IOL position, and surgical complications were evaluated. The mean BCVA was significantly improved 6 months postoperatively (0.26 ± 0.17 logMAR, P = 0.042) than preoperatively (0.50 ± 0.30 logMAR). No significant difference was observed between the preoperative and postoperative IOP (P = 0.138). The mean pupil diameter significantly reduced postoperatively than preoperatively (3.44 ± 0.35 mm vs. 7.28 ± 0.35 mm, P = 0.043). There was no significant decrease in CECC postoperatively (P = 0.225). The pupil shape was round-like, and photophobia disappeared in all patients. No intraoperative or postoperative complications occurred. Sutureless intrascleral IOL fixation combined with modified iris cerclage pupilloplasty is a safe and efficient procedure for treating aphakia traumatic mydriasis patients without sufficient capsular support.

General diffraction integral for converging freeform vectorial fields

Herein it is presented a new vector diffraction integral capable to compute the diffraction patterns for aspheric and freeform wavefronts, with different pupil shapes, and different polarization states. The aforementioned vector diffraction integral is based on the energy conservation theorem, the far field approximation, and the angular spectrum representation of optical fields. The integral is validated through illustrative examples whose results are as expected and coincides with the related works.

Case Report: Congenital Pseudoacorea in an Ocular Axenfeld-Rieger Syndrome: What is it?

This is a descriptive summary of the case of a patient with Axenfeld-Rieger syndrome associated with a congenital malformation of the iris and consequent pupillary morphological alteration of an atypical characteristic reported. This anomaly is unique in scientific literature and exhibits a peculiarity that we have called pseudoacorea: Hidden pupil. Other associated abnormal clinical findings were posterior embryotoxon, astigmatism, amblyopia, and exotropia. Diagnosis was achieved by instilling ocular mydriatics into the cul-de-sac that revealed this peculiarity. It is necessary to make a differential diagnosis with other pupillary pathologies such as corectopia, acorea and microcoria. Early detection of pathology and surgical management is necessary, since it would lead to a better visual prognosis for both amblyopia and strabismus. Among the malformations of the pupil, we can find polycoria (more than one pupil), dyscoria (abnormal pupil shape), corectopia (abnormal pupil position) and acorea (absence of pupil). In addition, morphologically normal pupils can denote other anomalies such as the microcoria described by Holth in 1923. Acorea is a rare anomaly, congenital or acquired, characterized by an absolute absence of the pupil both at rest and in mydriasis. In our case we prefer to differentiate it and name it pseudoacorea, since although there is a total absence of the pupil at rest thanks to the application of ocular mydriatics, a micropupil with discoric and corectopic characteristics is achieved. It is worth noting that we have not detected in the scientific literature any case described as the one that we will develop here. The case of a patient with Axenfeld-Rieger syndrome associated with a congenital malformation of the iris and consequent atypical pupillary morphological alteration is presented. This anomaly is unique in the scientific literature and presents a peculiarity that we have called pseudoacorea: Hidden pupil. Early detection of pathology and surgical management is necessary, since it would lead to a better visual prognosis for both amblyopia and strabismus.

Nondestructive rainbow trout (Oncorhynchus mykiss) freshness estimation by using an affordable open-ended coaxial technique.

In the present work, a nondestructive device set up for a rapid and reliable freshness assessment of rainbow trout during 10 days of storage in ice was evaluated. The device was characterized by a vector network analyzer interfaced with an open coaxial probe to be placed in contact with the fish eye. The acquisition of the reflected scattering parameter (S11), which is the ratio between the amplitude of the reflected and the incident signal, was assessed in the 50kHz-3GHz spectral range. S11 is composed of a real part and an imaginary part, and both parts were used to predict quality index method for freshness evaluations. Partial least squares regression predictive models of the demerit scores related to fish eye attributes (eye pupil and eye shape) and the day of storage were set up. The main results showed that both the real and imaginary parts of the S11 decrease as a function of storage time. The combination with multivariate analysis allowed to set up predictive models of the storage time and the demerit scores with R2 values up to 0.946 (root mean square error [RMSE]=0.88 days) and 0.942 (RMSE=3.17 demerit scores related to the fish eyes attributes), respectively (external validation). According to our results, the proposed cheap solution appears a useful tool for the freshness assessment of rainbow trout. PRACTICAL APPLICATION: This work shows that dielectric properties have the potential to discriminate stored fish according to their freshness quality. A device based on this principle can play a significant role in the postharvest processes, contributing to higher product quality and safety and supporting producers and retailers during the qualitative inspections.

A novel Y-shaper and chopper for small pupil management in cataract surgery: The initial experience.

Small pupil is a well-known risk factor for causing cataract surgery complications such as vitreous loss, anterior capsular tear, increased inflammation, and an irregular pupil shape. Because all currently available pharmacological approaches of dilating the pupil before or during cataract surgery cannot guarantee the result, the surgeon sometimes resorts to the use of mechanical pupil-expanding devices. However, these devices can increase the overall surgical cost and operative time. Very frequently, a combination of the two is needed; thus, we present the Y-shaped chopper designed by the authors, which serves the purpose of managing the intra-operative miosis and allows simultaneous nuclear emulsification.

Effect of pupil dilation on biometric iris recognition systems for personal authentication.

To study the effect of pupil dilation on a biometric iris recognition (BIR) system for personal authentication and identification. A prospective, non-randomized, single-center cohort study was conducted on patients who reported for a routine eye check-up from November 2017 to November 2019 (2 years). An iris scanning device "IRITECH-MK2120U" was used to initially enroll the undilated eyes. Baseline scans were taken after matching with the enrolled database. All eyes were topically dilated and matched again with the enrolled database. The Hamming distance (a measure of disagreement between two iris codes) and recognition status were recorded from the device output, and eyes were evaluated by slit-lamp ophthalmoscopy with special emphasis on pupil shape, size, and texture. All 321 enrolled eyes matched after topical dilation. The pupil size had a significant effect on Hamming distance with a P value <0.05. There were no false matches. A correct recognition rate of 100% was obtained after dilation. No loss of iris texture or pupil shape was observed after dilation. A BIR system is a reliable method for identification and personal authentication after pupil dilation. Topically dilated pupils are not a cause for non-recognition of iris scans.

The Influence of the Aperture Stop Fractal Shape of an Optical System on the Illuminance Distribution

In the article the options for the application of aperture shapes with fractal properties in the design of optical systems are considered. Calculations of mathematical models of point spread functions of a diffraction-limited optical system are performed. The diffraction patterns of the light distribution in these systems are presented, and the point spread functions are considered for various shapes of the aperture stop. Analytical expressions are obtained for the light distribution depending on the pupil shape, which can be used to control the process of image formation. The pupil shape, which has the shape of an equilateral triangle, is chosen as the basic one, and the shape of the pupil as a "Koch snowflake" curve is also considered. Using the Fraunhofer integral, the dependences of the distribution of the spectral density of the complex amplitude on the aperture located on an opaque screen are derived in the Fraunhofer approximation and under the condition of illumination by a plane monochromatic wave. Using the relationship with the complex amplitude, the sought-for intensity distribution in the plane of the diffraction pattern is obtained. Taking into account the simplifications adopted in this article, the solution of the Fraunhofer integral is found, by setting the integration limits, depending on: the selected aperture profile, the coordinate system chosen for it, and the position of nodal points in this system

Diversity and evolution of amphibian pupil shapes

Abstract Pupil constriction has important functional consequences for animal vision, yet the evolutionary mechanisms underlying diverse pupil sizes and shapes are poorly understood. We aimed to quantify the diversity and evolution of pupil shapes among amphibians and to test for potential correlations to ecology based on functional hypotheses. Using photographs, we surveyed pupil shape across adults of 1294 amphibian species, 74 families and three orders, and additionally for larval stages for all families of frogs and salamanders with a biphasic ontogeny. For amphibians with a biphasic life history, pupil shape changed in many species that occupy distinct habitats before and after metamorphosis. In addition, non-elongated (circular or diamond) constricted pupils were associated with species inhabiting aquatic or underground environments, and elongated pupils (with vertical or horizontal long axes) were more common in species with larger absolute eye sizes. We propose that amphibians provide a valuable group within which to explore the anatomical, physiological, optical and ecological mechanisms underlying the evolution of pupil shape.

Twofold technique for iridodialysis repair

Disinsertion of iris leads to debilitating sequelae like diplopia and glare. Hence, iridodialysis repair is essential to optimize the visual quality. Iris base repair often leads to corectopia that necessitates an additional procedure to optimize the pupil shape and size. Twofold technique helps to achieve both the aspects. To highlight the technique of twofold iridodialysis repair. The video highlights the method of twofold iridodialysis repair, wherein nonappositional repair is followed by single-pass four-throw (SFT) pupilloplasty that allows adequate closure of varied degrees of iridodialysis along with centration of eccentric pupil. The twofold technique is a combination of nonappositional iris repair and SFT procedure. It can be clinically applied in all cases of iridodialysis with varied degrees of severity. https://youtu.be/OncBdz2UIBY.

Whole genome assembly of the armored loricariid catfish Ancistrus triradiatus highlights herbivory signatures

The catfish Ancistrus triradiatus belongs to the species-rich family Loricariidae. Loricariids display remarkable traits such as herbivory, a benthic lifestyle, the absence of scales but the presence of dermal bony plates. They are exported as ornamental fish worldwide, with escaped fishes becoming a threat locally. Although genetic and phylogenetic studies are continuously increasing and developmental genetic investigations are underway, no genome assembly has been formally proposed for Loricariidae yet. We report a high-quality genome assembly of Ancistrus triradiatus using long and short reads, and a newly assembled transcriptome. The genome assembly is composed of 9530 scaffolds, including 85.6% of ray-finned fish BUSCOs, and 26,885 predicted protein-coding genes. The genomic GC content is higher than in other catfishes, reflecting the higher metabolism associated with herbivory. The examination of the SCPP gene family indicates that the genes presumably triggering scale loss when absent, are present in the scaleless A. triradiatus, questioning their explanatory role. The analysis of the opsin gene repertoire revealed that gene losses associated to the nocturnal lifestyle of catfishes were not entirely found in A. triradiatus, as the UV-sensitive opsin 5 is present. Finally, most gene family expansions were related to immunity except the gamma crystallin gene family which controls pupil shape and sub-aquatic vision. Thus, the genome of A. triradiatus reveals that fish herbivory may be related to the photic zone habitat, conditions metabolism, photoreception and visual functions. This genome is the first for the catfish suborder Loricarioidei and will serve as backbone for future genetic, developmental and conservation studies.

Intraocular Lymphoma in Dogs - Findings of Contrast Enhanced Ultrasound and ARFI Elastography

Background: Ocular lymphoma can affect the iris, conjunctiva, choroid, and retina and is mostly associated with multicentric disease. Elastography is an ultrasound technique that provides noninvasive, pain-free assessment of tissue stiffness. It has the ability to assess subtle changes throughout the organ as well as focal lesions. Microbubble contrast ultrasound enables the detection of incipient vascular flows, which are difficult to detect using traditional ultrasound methods. This study aimed to describe acoustic radiation force impulse (ARFI) elastography and microbubble contrast ultrasound findings in the eyes of two dogs diagnosed with intraocular T-cell lymphoma. Cases: Case 1. Physical examination revealed an exophytic mass in the left eye. Schirmer test revealed a secretion of 22 mm/min. Negative threat reflex, glare, direct pupillary light reflex, and consensual response were also noted. Biomicroscopy revealed hyperplasia of the third eyelid, overlapping with the affected eye. When the membrane was removed, moderate conjunctival hyperemia, mucoid secretion, and buphthalmia were observed. In addition, significant corneal edema was present, making it impossible to visualize the anterior chamber and perform fundus examination. The intraocular pressure, as measured with a rebound tonometer, was 39 mmHg. B-mode ultrasonography identified amorphous, hyperechoic, and heterogeneous structures throughout the anterior chamber, iris, and ciliary body. The elastogram showed that the mass had greenish tones and intermediate stiffness, and the mean SWV of the ciliary body and iris was 2 m/s. Contrast-enhanced ultrasound (CEUS) revealed vascularization of the neoformation region, with wash-in, peak, and wash-out values of 9.89 s, 24.56 s, and 107.87 s, respectively. Case 2. On physical examination, a change in the shape of the right pupil was observed. Schirmer test revealed a secretion of 20 mm/min, with negative threat, glare, and pupillary reflexes to direct and consensual light. Biomicroscopy revealed neoformation from 7 am to 11 am in the sclera, retina, and choroid complex, concomitant with dyscoria and conjunctival hyperemia. The intraocular pressure, as measured by rebound tonometry, was 33 mmHg. Fundoscopy revealed a mass in the temporal region and focal retinal detachment. No changes were observed in the contralateral eye. B-mode ultrasound revealed an increase in volume in the temporal region of the iris, ciliary body, and choroid with diffuse heterogeneity and partial retinal detachment. Elastographic examination revealed shades of green and yellow compatible with increased tissue stiffness. On quantitative examination, the mean SWVs of the ciliary body and iris were 3.14 m/s. On CEUS, the neoformation region presented wash-in, peak, and wash-out values of 8.67 s, 22.33 s, and 80.20 s. Discussion: B-mode ultrasonography established the tumor extent and evaluated echogenicity, verifying the involved ocular structures. The examination played an important role in the diagnosis as well as clinical management. ARFI elastography can detect small tissue changes, helping to define nodules and masses more reliably, in addition to allowing the verification of tissue stiffness. In both dogs, it was possible to verify that the masses presented greater rigidity than the adjacent tissues both qualitatively and quantitatively. In previous studies, it was found that cutaneous and breast lymphomas in humans were more rigid than adjacent tissues on elastography. This increase in rigidity and heterogeneity observed on elastograms can be explained by the extramedullary interactions of the matrix in T-cell lymphomas. Tumor growth is dependent on the blood supply, which was evaluated using CEUS in these cases. Furthermore, the ciliary body contrast filling times were longer than those described in normal dogs. Keywords: eye, surgery, diagnostic imaging, pain, veterinary ophthalmology, neoplasia. Título: Linfoma intraocular em cães - achados da ultrassonografia contrastada e elastografia ARFI Descritores: olho, cirurgia, diagnóstico por imagem, dor, oftlamologia veterinária, neoplasia.

Reversed scleral tunnel technique for repair of iridodialysis after blunt force trauma: a retrospective clinical study

BackgroundTo investigate the efficacy and safety of reversed scleral tunnel technique for repairing iridodialysis after blunt force trauma.MethodsA total of 51 eyes of 51 patients with iridodialysis undergoing surgery were included in this study. Patients were divided into 2 groups: group A (the reversed scleral tunnel technique) and group B (the control group). Before the procedure and at 1, 3, and 6 months afterward, data on the patients’ age, gender, treatments, diagnosis, mechanism of injury, best-corrected visual acuity (BCVA), intraocular pressure (IOP), degree of iridodialysis, lens status, concomitant ocular damage, number of sutures, complications, and follow-up time were collected and compared between the 2 groups.ResultsIridodialysis was repaired and the pupil shape was restored to nearly round in all eyes. Standard phacoemulsification or lens removal was performed in all eyes. A final BCVA ≥20/60 was achieved in 13 eyes (48.1%) in Group A and 13 eyes (54.2%) in Group B. The IOP remained stable during the follow-up period in all eyes except 2 eyes (7.4%) in Group A and 3 eyes (12.5%) in Group B with angle recession. There were no statistically significant differences in BCVA and IOP between group A and group B. Intraoperatively, A significantly lower percentage of extensive subconjunctival hemorrhage occurred in Group A compared to Group B (1 eye versus 24 eyes, χ2 = 47.1, P = 0.00). Hyphema was observed in 2 eyes (7.4%) in Group A and 1 eye (4.2%) in Group B. Postoperatively, two eyes (7.4%) in Group A and 2 eyes (8.3%) in Group B developed retinal detachment. No other complications were noted during the follow-up period.ConclusionsThe reversed scleral tunnel technique is a safe and effective approach for repairing iridodialysis after blunt force trauma with few complications, favorable cosmetic and visual outcomes.

Sutureless Manual Extracapsular Cataract Extraction with Club

Purpose: To evaluate the efficacy and safety of cataract extraction through small pupil with the help of a specially designed instrument called club. Study Design: Interventional case series. Place and Duration of Study: Euro eye clinic from January 2019 to December 2019. Methods: Seventeen consecutive patients with pupil diameter of &lt;4mm after maximal pharmacological dilatation were recruited for study. Inclusion criteria was patients with less than 4mm pupil size after maximum pharmacological dilation. Patient with previous anterior segment surgery and small pupil with posterior synechea were excluded. The instrument (club) was originally designed for breaking posterior synechae. Sutureless Manual Extracapsular Cataract Extraction (SMECE), more commonly known as MSICS, was performed in all cases. After tunnel formation and capsulotomy, club was used to bring lens edge out in pupillary margin. Lens was then maneuvered into anterior chamber and expressed out. Results: All 17 patients had successful SMECE. In one patient pupil was stretched before applying instrument. None of the patients had posterior capsular rupture or hyphaema. Conclusion: This instrument designed in Center of Ophthalmic Instrument and Equipment Designing (COIED) is very useful, safe and cost effective. In Extra Capsular Cataract Extraction (ECCE) or SMECE, surgeons usually do keyhole iridotomy, mechanical stretching or multiple sphincterotomies for managing small pupil. With this new instrument, cataract extraction can be done without surgical trauma to the pupil, thus preserving pupil shape. Key Words: Sutureless Manual Extra capsular Cataract Extraction (SMECE), Manual Small Incision Cataract Surgery (MSICS), Miosis.