Iris Surface Research Articles

Noise-Robust Biometric Authentication Using Infrared Periocular Images Captured from a Head-Mounted Display

This study proposes a biometric authentication method using infrared (IR)-based periocular images captured in virtual reality (VR) environments with head-mounted displays (HMDs). The widespread application of VR technology highlights the growing need for robust user authentication in immersive environments. To address this, the study introduces a novel periocular biometric authentication system optimized for HMD usage. Ensuring reliable authentication in VR environments necessitates overcoming significant challenges, including flicker noise and infrared reflection. Flicker noise, caused by alternating current (AC)-powered lighting, produces banding artifacts in images captured by rolling-shutter cameras, obstructing biometric feature extraction. Additionally, IR reflection generates strong light glare on the iris surface, degrading image quality and negatively impacting the model’s generalization performance and authentication accuracy. This study utilized the AffectiVR dataset, which includes noisy images, to address these challenges. In the preprocessing phase, iris reflections were removed, reducing the Equal Error Rate (EER) from 6.73% to 5.52%. Furthermore, incorporating a Squeeze-and-Excitation (SE) block to mitigate flicker noise and enhance model robustness resulted in a final EER of 6.39%. Although the SE block slightly increased the EER, it significantly improved the model’s ability to suppress noise and focus on critical periocular features, ensuring enhanced robustness in challenging VR environments. Heatmap analysis revealed that the proposed model effectively utilized periocular features, such as the skin around the eyes and eye contours, compared to prior approaches. This study establishes a crucial groundwork for advancing robust biometric authentication systems capable of overcoming noise challenges in next-generation immersive platforms.

Morphologic features of iris in highly myopic eyes based on a novel swept-source optical coherence tomography.

To investigate the morphologic features of iris in the highly myopic (HM) eyes using a novel swept-source optical coherence tomography (SS-OCT). In this retrospective case-control study, 100 eyes of 100 patients scheduled to have cataract surgery were included, categorized into the control (22 mm< AL < 24.5 mm) and HM (AL ≥ 26 mm) groups. Iris volume (IV), area of anterior iris surface (IS), area of posterior IS, and average iris thickness (IT), as well as anterior chamber volume (ACV) and trabecular-iris space at 500 µm (TISA 500) were evaluated using SS-OCT. The associated factors with morphologic features of iris were also investigated. The HM group showed significantly larger IV and area of anterior and posterior IS than the control group (all P < 0.001), while no difference was identified in IT between the groups. Similar trend in IV was seen in the superior and nasal segments, and area of anterior and posterior IS showed similar trends in all segments except the temporal segment. The IV, area of anterior and posterior IS were all positively correlated with AL (all P < 0.001). Multivariate linear regression revealed that a larger IV was associated with greater ACV. Both larger areas of anterior IS and posterior IS were associated with male, longer AL, greater ACV, and smaller TISA 500. The HM eyes showed larger IV and area of IS than the control eyes, indicating a coronal expansion of the iris with AL. Iris morphology correlated with anterior chamber angle configuration.

Anterior segment optical coherence tomography for the detection of silicone oil emulsification on the iris surface

BackgroundTo investigate the presence of silicone oil (SO)-emulsification on the anterior iris surface with anterior segment optical coherence tomography (AS-OCT).MethodsIn this single-center cross-sectional study, vitrectomized eyes with SO tamponade that underwent AS-OCT imaging and gonioscopy examination during the postoperative follow-up visits, were reviewed.Results45 eyes of 42 consecutive patients were included. In 35.6% of the eyes (n = 16) emulsified SO droplets were detected in the anterior chamber (AC) angle by gonioscopy and in 55.6% (n = 25) on the anterior iris surface by AS-OCT imaging. The presence of SO emulsifications in the AC-angle correlated with the presence of SO emulsifications on the anterior iris surface (OR = 13.4, 95% CI [2.179–82.130]; p = 0.005). The accuracy of the AS-OCT predicting the presence of SO in the AC-angle was 71.0% and the sensitivity was 87.5%. No significant association between SO droplets in the AC and other clinical parameters including endotamponade-duration or type of silicone oil were found. The presence of emulsified SO droplets on the anterior iris surface detected by AS-OCT was significantly correlated to postoperative IOP rise (p = 0.027).ConclusionAS-OCT is a suitable method for the detection of SO on the anterior iris surface. SO droplets on the iris surface correlate with elevated postoperative IOP and with the presence of SO in the AC detected by gonioscopy, therefore AS-OCT might be used as a screening method for the detection of SO migration into the AC.Trial registration numberInstitutional Review Board of the Hamburg Medical Chamber (Ethik-Kommission der Ärztekammer Hamburg): 2023-300372-WF.

Eyes on the unseen-lung adenocarcinoma presenting as iris and ciliary body metastases: A case report

A 65-year-old male was referred for a left-eye irido-ciliary body mass for further evaluation. In the left eye, there was a small, well-circumscribed, white gelatinous, amelanotic mass noted temporally in the angle with a filiform appearance. The ultrasound biomicroscopy showed a large hyperreflective mass at 3 o’clock in the ciliary body, the anterior chamber, angle, iris, and anterior surface of the lens. Iris tissue biopsy was done, and the sample was sent for histopathology with immunohistochemistry. The histopathological examination identified the tumor composed of malignant cells forming glandular structures alongside papillary projections. Immunohistochemical tests showed positive results for CK (AE1/AE3). The diagnosis of a poorly differentiated adenocarcinoma was made. A whole-body PET scan and CT scan were done. The imaging features were suggestive of primary bronchogenic malignancy of the right lung with systemic metastases. The lung biopsy confirmed the diagnosis. Iridociliary mass warrants a detailed evaluation for appropriate management by a multidisciplinary team.

Longstanding iris foreign body to treat or not to treat!

A 61 year female presented with whitish discolouration of left eye noticed few days ago with a forgotten history of trauma 28 years ago for which a consultation was made and was asked for review with orbital x-ray, which was not done as she was asymptomatic. On examination, her best corrected visual acuity was 6/6 both eyes. Examination of right eye was unremarkable except for early lens changes, while left eye showed a nebular corneal opacity, suggesting entry wound. A brown coloured foreign body was seen stuck to iris surface temporally, measuring 4*3mm with degenerative changes over it and exposing underlying pigment epithelium with focal cataract. Rest of anterior segment, gonioscopy and fundus examination were normal. A thorough search for other intraocular foreign bodies (IOFBs) was made, revealing no other IOFBs. Anterior segment optical coherence tomography (AS-OCT) and ultrasound biomicroscopy (UBM) demonstrated foreign body limited to iris surface, while orbital x-ray showed no evidence of metallic foreign body and electroretinogram (ERG) showed mildly decreased amplitude of b-wave. Plan for foreign body removal with cataract surgery was made as per patient’s request for cosmesis, and was retrieved through viscoexpression after a failed attempt to remove it through magnetic forceps thereby confirming its non-metallic nature. Special care was taken during capsulorhexis to not damage the intact capsule. Rest of cataract surgery was performed as usual and anterior chamber wash was done to flush all the debris. Post operative picture shows an area of partial and full thickness iris defect while maintaining a good visual acuity. The debate for removal of longstanding, well encapsulated, inert foreign body over iris without functional impairment depends on multiple factors.[1,2] Which in our case was due to the patient’s demand for cosmesis. Video link: https://youtu.be/pC3ZRoqxB8o

Quantitative signs on ultrasound biomicroscopy images associated with the status of silicone oil emulsification within the eye.

Silicone oil (SO) is a commonly used intraocular tamponade in the treatment of rhegmatogenous retinal detachment (RRD). SO emulsification is a common complication after SO injection. This study aimed to investigate correlations between SO emulsification signs on ultrasound biomicroscopy (UBM) and the real number/size of SO droplets. An observational, cross-sectional study. Thirty-five RRD patients (19 males; 35 eyes) who underwent pars plana vitrectomy and SO injection were enrolled in the study. SO emulsification signs on UBM (endothelial deposits, floating droplets, ghost images, hyperoleon, anterior chamber angle impregnation, anterior iris surface impregnation, posterior iris surface impregnation and ciliary body impregnation) were acquired and quantified two days before SO removal, while real number/size of the SO droplets with a diameter in 0.4-20 μm in the first 2 mL washout fluid collected intraoperatively during SO removal were assessed by Coulter counter. Then the correlations between these values were explored. The grade of tissue impregnation and hyperoleon area in the anterior chamber demonstrated significant correlations with the number of large (5-20 μm) SO droplets (r = 0.336; P = 0.048 and r = 0.350; P = 0.039, respectively); however, no significant correlations were observed with the total number of droplets (0.4-20 μm)or the number of small (0.4-5 μm) droplets (both P ＞ 0.05). The UBM quantitative grade of tissue impregnation and hyperoleon area in the anterior chamber could provide a noninvasive overview of the actual degree of SO emulsification before SO removal surgery.

Symptomatic pigment dispersion with intraocular pressure elevation attributed to intracameral moxifloxacin after open-globe injury

Background: Intracameral moxifloxacin is commonly used following intraocular surgery to prevent endophthalmitis. Pigment dispersion is a rare complication of moxifloxacin use that has mainly been reported following systemic administration. Case presentation: We report a case of unilateral pigment dispersion three weeks after open-globe repair with intracameral moxifloxacin presenting with pain, redness, photophobia, elevated intraocular pressure, marked pigment liberation, new iris transillumination defects and pigment deposits on the anterior iris surface. Conclusion: Symptomatic unilateral pigment dispersion with IOP elevation following intracameral moxifloxacin is a rare entity, but it is a crucial complication for clinicians to be aware of as intracameral antibiotic use following intraocular surgery becomes more frequent.

Epstein-Barr virus-positive iris diffuse large B-cell lymphoma detected by metagenomic next-generation sequencing

PurposeEpstein-Barr virus (EBV)-positive diffuse large B-cell lymphoma (DLBCL) is a relatively rare subtype of DLBCL. Herein, we report a case of a patient with EBV-positive iris DLBCL after undergoing penetrating keratoplasty and discuss its possible pathogenesis.MethodsA 72-year-old male patient presented to our hospital with progressive blurring of vision in the left eye for the past 4 months. Small white nodular lesions were observed on the iris and retinal surface of the left eye, with a white cloud-like opacity in the vitreous cavity.ResultsThe patient was eventually diagnosed with EBV-positive iris DLBCL after undergoing pathological and metagenomic tests. After injecting methotrexate in the left vitreous cavity and administering systemic and local antiviral treatments, the ocular lesions disappeared.ConclusionEBV infection, drug immunosuppression, and aging-related immune deterioration may play significant roles in the pathogenesis of EBV-positive iris DLBCL.SynopsisEpstein-Barr virus (EBV)-positive diffuse large B-cell lymphoma (DLBCL) is a new subtype of DLBCL, which rarely occurs. Herein, we report a case of a patient with EBV-positive iris DLBCL after undergoing penetrating keratoplasty and discuss its possible pathogenesis.

Possible Unilateral Iris Melanoma in a Cat

A tumor known as feline iris melanoma has a high chance of metastasizing and is characterized by multifocal, golden yellow to brown pigmented patches in the iris. Despite the fact that cats of any age can develop this tumor, there is no breed or sex-specific susceptibility. The case material was a female Russian blue cat that was neutered at the age of 5, weighed 4.5 kg, and was taken to the surgical clinic of the faculty of veterinary medicine at the University of Siirt. According to the patient's medical history, a brown spot-like pigmented region had developed on the right eye's iris two months prior, and up until the cat was brought to the clinic, the pigmented patches in the iris grew in number and size. As a result of routine clinical examination, tonometry, haematological and biochemical examinations, uveal cysts and iris freckles with similar clinical symptoms were eliminated and it was concluded that the pathological condition was iris melanoma. In addition, it was determined that melanoma foci were involved only on the iris surface in line with the available possibilities and did not metastasise to other tissues and organs of the eye. Since the disease was in the initial stage, the general condition of the patient was good after clinical examinations and the owner of the patient did not accept enucleation, it was decided not to perform any intervention. The owner of the patient was instructed that during the follow-up phase, the foci should be checked and the patient should continue to be under supervision. When the patient was summoned back for a follow-up examination three months later, it was decided to undertake enucleation in case any potential melanoma foci or metastases had grown in other eye tissues or organs.

Early pigment spot segmentation and classification from iris cellular image analysis with explainable deep learning and multiclass support vector machine.

Globally, retinal disorders impact thousands of individuals. Early diagnosis and treatment of these anomalies might halt their development and prevent many people from developing preventable blindness. Iris spot segmentation is critical due to acquiring iris cellular images that suffer from the off-angle iris, noise, and specular reflection. Most currently used iris segmentation techniques are based on edge data and noncellular images. The size of the pigment patches on the surface of the iris increases with eye syndrome. In addition, iris images taken in uncooperative settings frequently have negative noise, making it difficult to segment them precisely. The traditional diagnosis processes are costly and time consuming since they require highly qualified personnel and have strict environments. This paper presents an explainable deep learning model integrated with a multiclass support vector machine to analyze iris cellular images for early pigment spot segmentation and classification. Three benchmark datasets MILE, UPOL, and Eyes SUB were used in the experiments to test the proposed methodology. The experimental results are compared on standard metrics, demonstrating that the proposed model outperformed the methods reported in the literature regarding classification errors. Additionally, it is observed that the proposed parameters are highly effective in locating the micro pigment spots on the iris surfaces.

Iris nodules secondary to retained PFO in the anterior chamber following macula-off rhegmatogenous retinal detachment repair.

To describe a case of PFO retention, migration into the anterior chamber, and the subsequent formation of iris nodules following the repair of a giant retinal tear. Patient data was collected via manual chart review. All patient information was deidentified. Slit lamp photos demonstrate nodules on the iris surface and retained PFO in the anterior chamber. Ultrasound biomicroscopy shows multifocal hyperreflective signals on the iris surface, corresponding to the retained PFO within the iris. Retention and migration of PFO to the anterior chamber following retinal detachment repair can lead to formation of nodules on the surface of the iris.

Comparative study of the effects of laser peripheral iridotomy and cataract surgery on anterior chamber angle parameters in primary angle closure suspect patients

IntroductionProphylactic laser peripheral iridotomy (LPI) and cataract surgery are considered the primary treatments for primary angle closure suspect (PACS) as they have proven effectiveness in widening the iridocorneal angle and...

Autosomal recessive bestrophinopathy combined with neurofibromatosis type 1 in a patient

BackgroundNeurofibromatosis type 1 (NF1) is a multisystem genetic disorder that may affect multiple systems of the body. Autosomal recessive bestrophinopathy (ARB) is a rare retinal dystrophy caused by autosomal recessively mutations in bestrophin 1 (BEST1) gene. So far, we have not retrieved any case report of the same patient with both NF1 and BEST1 gene mutations.Case presentationAn 8-year-old female patient with café-au-lait spots, freckling on skin presented to our ophthalmology clinic for routine ophthalmological examination. Her best corrected visual acuity (BCVA) was 20/20 in both eyes. Slit-lamp examination of both eyes revealed few yellowish-brown dome-shaped Lisch nodules over the iris surface. Fundus examination was notable for bilateral confluent yellowish subretinal deposits at macula, few yellow flecks at temporal retina, and cup-to-disc ratio of 0.2. Optical coherence tomography (OCT) revealed subretinal fluid (SRF) involving the fovea, elongated photoreceptor outer segments and mild intraretinal fluid (IRF) at bilateral macula. Fundus autofluorescence demonstrated hyperautofluorescence in the area corresponding to the subretinal deposits. Whole-exome sequencing and Sanger sequencing were used to investigate genetic mutation in the patient and her parents. A BEST1 gene heterozygous missense c.604 C > T (p.Arg202Trp) was identified in the patient and her mother. Also, the patient carries an NF1 nonsense mutation c.6637 C > T (p.Gln2213*) with the mosaic generalized phenotype. There were no visual impairments or obvious neurological, musculoskeletal, behavioral or other symptoms in this patient, so she was managed conservatively and advised to follow up regularly for a long time.ConclusionsARB and NF1, which are caused by two different pathogenic gene mutations, have rarely coexisted in the same patient. The discovery of pathogenic gene mutations may play a crucial role in more accurate diagnostics and genetic consultations for individuals and their families.

Long-term course with iris changes after trabeculectomy for uveitic glaucoma associated with iris mammillation: a case report

BackgroundIris mammillation is a rare disease characterized by the distribution of multiple nodules on the iris surface. The course of uveitic glaucoma with iris mammillation has never been reported.Case presentationA 56-year-old woman, who presented with unilateral decreased vision, visited our hospital for treatment of uveitic glaucoma in the right eye. Multiple nodules were scattered over the iris surface in that eye. This case was diagnosed as iris mammillation on clinical findings. After excluding malignant tumors such as melanoma, trabeculectomy was performed. The resected iris had no pathologically malignant findings. The iris nodules evolved to a sand-like appearance, and the intraocular pressure remained stable without recurrent inflammation 7 years after trabeculectomy.ConclusionsIn a case of unilateral uveitic glaucoma with iris mammillation, filtration surgery was performed after excluding the presence of a malignancy, and the long-term postoperative course has been stable.

Spherical-Orthogonal-Symmetric Haar Wavelet for Driver's Visual Detection

This work proposes a spherical-orthogonal-symmetric Haar wavelet to decompose and reconstruct spherical iris signals to obtain stronger geometric features of iris surface. It compares its feature extraction abilities of spherical harmonics, semi-orthogonal and nearly orthogonal spherical Haar wavelet. The developed spherical-orthogonal-symmetric Haar wavelet with a convolutional neural network is also proposed for drivers&#x2019; iris recognition. It can effectively capture the local fine features of iris spherical surface, and has stronger ability of iris recognition than semi-orthogonal or nearly orthogonal spherical Haar wavelet bases.

Anterior Segment Characteristics of Eyes with Anterior Chamber Depth Less than 2.8mm and Axial Length Greater than 25mm.

This study aimed to investigate anterior segment parameters of eyes, with anterior chamber depth (ACD) less than 2.8mm and axial length greater than 25.0mm. This cross-sectional study included 180 myopic eyes of 180 consecutive patients with axial length greater than 25.0mm. Patients were divided into low ACD (ACD < 2.8mm, n = 56) and normal ACD (ACD ≥ 2.8mm, n = 124) groups. Anterior segment parameters were measured using Scheimpflug imaging and ultrasound biomicroscopy. A general linear model was used to compare parameters between the two groups, after adjusting for age and spherical equivalent. Compared with the normal ACD group, the low ACD group had lower values for the following parameters: corneal diameter, trabecular-anterior iris surface angle, angle-opening distance at 500μm, anterior chamber volume, anterior chamber width, anterior vault, iris thickness at 500μm, ciliary sulcus-to-sulcus diameter, distance between cornea and sulcus, trabecular-ciliary process distance, maximum ciliary body thickness, ciliary process length, relative anterior vault, relative distance between cornea and sulcus, and relative lens position (general linear model, p < 0.05). In contrast, central corneal thickness, iris curvature, lens thickness, lens vault, and iris-ciliary angle were greater in the low ACD group (general linear model, p < 0.05). A smaller anterior segment, as well as a thicker and more anteriorly positioned lens, may correlate with shallow ACD in eyes with long axial length.

Argon laser trabeculoplasty for congenital ectropion uveae: Case report and review of the literature.

A 18-year-old woman with unilateral glaucoma secondary to congenital ectropion uveae (CEU) in the right eye, without other systemic and ocular associations. Intraocular pressure (IOP) was uncontrolled under topical therapy. The visual field (VF) was within normal limits; retinal nerve fiber layer (RNFL) thickness, as evaluated by Optical Coherence Tomography (OCT), was reduced. The patient refused surgical intervention. After evaluation of the iridocorneal angle, ALT was performed as follows: 95 spots were applied for the 270 ° of visible trabecular meshwork using a laser beam diameter of 50 μm, an exposure time of 0.1 s and a power of 750 mw). Mean IOP in the right eye, as evaluated by diurnal tonometric curve, was 10 mmHg, 16 mmHg and 20 mmHg respectively one month, four months and eight months after ALT, with no additional topical therapy, and 18 mmHg twelve months after ALT with topical therapy. CEU is a rare, non-progressive anomaly characterized by the proliferation of iris pigment epithelium on anterior surface of iris; glaucoma, in this disorder, is often poorly controlled with medical therapy alone. In a phase of initial glaucomatous damage and with a not particularly high IOP, as in this case, ALT could be an alternative therapeutic option at least in the short-term, when surgery is not feasible immediately. In fact, given its limited effectiveness over time, ALT can be used as a temporary control measure of IOP, pending surgery to become feasible.

Unusual Presentation of Thelazia callipaeda in the Anterior Chamber of a Human Eye

Introduction: We presented a 53 years old female with redness and pain of right eye for the past 3 months. Slit-lamp biomicroscopy revealed circumciliary congestion with a mobile, curved, white, rod-shaped parasite in the anterior chamber (AC) on the inferior surface of iris. For definitive diagnosis and management, we removed the parasite from the AC through limbal incision. Microbiological examination identified “Thelazia callipaeda”. Thelazia callipaeda is usually detected in the conjunctival sac and lacrimal sac. However, in this case from Lumbini Eye Institute and research centre, Western Nepal, the parasite was found in the anterior chamber of a human eye which is an unusual location.

Therapeutic potential of pupilloplasty combined with phacomulsification and intraocular lens implantation against uveitis-induced cataract.

To evaluate the therapeutic effect of pupilloplasty combined with phacomulsification and intraocular lens implantation (PPI) in uveitis-induced cataract. Total 28 patients with uveitis-induced cataract were enrolled. Within 3mo before the PPI, 7 cases accompanied with glaucoma maintained carteolol hydrochloride for lowering intraocular pressure, and 1 case maintained glucocorticoid for anti-inflammation. The baseline characteristics, treatment processes, and outcomes of enrolled cases were retrospectively analyzed. Hematoxylin and eosin (HE) staining was performed to reveal the histopathological changes of iris tissues. Iris hemorrhage was the only intraoperative complication observed in 2 cases. After the surgery, normal intraocular pressure, right position of intraocular lens, and improved visual gain [best corrected visual acuity (BCVA)>0.5] were achieved. Postoperative keratic precipitates was observed in 2 cases, which was recovered within 1wk. During the follow-up of 5-10y, no recurrence of uveitis was found in 27 cases (96.43%). Uveitis only recurred in one case with the onset of ankylosing spondylitis. HE staining showed iris stroma (all samples), pigment cell hyperplasia in pigment epithelium (n=9) and stroma (n=19), inflammatory cell infiltration in iris (n=7), and neovascularization in iris surface (n=2). PPI improves the visual gain and prevents the long-term recurrence of uveitis in patients with uveitis-induced cataract, including those with preoperative intraocular pressure abnormality (glaucoma) and inflammation (active uveitis). Uveitis presents stroma atrophy, pigment cell hyperplasia, and inflammatory cell infiltration, even in a quiet state.

Iris Melanoma: Genetic Pathway, Staging, Histopathology, Clinical Features, Diagnostic Imaging, Treatment and Management

Introduction- Iris melanomas mainly grow in the anterior chamber or along the iris surface, and by local extension; they commonly invade the anterior chamber angle and anterior ciliary body. Iris melanomas account for 2–3% of all uveal melanomas, with the diffuse variety accounting for about 10% of all iris melanomas. Methodology-A systematic review is a technical tool that basically describes a more or less systematic way of collecting and synthesizing past research by integrating findings and perspectives from a variety of empirical findings. In this study, authors conducted a systematic assessment of 51 research articles on the subject of "Iris Melanoma" in order to examine and compare the various approaches and outcomes. This comprehensive review summarizes all 51 research articles in the most accessible manner to discuss the Genetic pathway, Staging, Histopathology, Clinical features, Diagnostic Imaging, Treatment, and Management. Results-Iris melanomas are discovered early and treated fast because they are apparent when they are little. As a result, patients with this tumor had a better prognosis than those with posterior uvea tumors. Conclusion- Radiotherapy or surgical resection are usually used in this situation. A combination of radiotherapy and surgery may be employed in some circumstances. Conservative treatment is an excellent option for enucleation since it provides for effective tumor control locally. Keywords:melanoma, Diagnosis, Management, Stages, Eye-care.