Iris Diameter Research Articles

Age-specific distribution of oculometric parameters and myopia in children aged 8-12y.

To describe the distribution of ocular biometrics and to evaluate its associations with refractive error and to assess the contribution from ocular parameters to refractive error among Chinese myopic children. This cross-sectional study evaluated subjects aged 8-12y. Keratometry, ocular biometry, and cycloplegic autorefraction were performed on each subject. Spherical equivalent refraction (SER) and ocular biometrics were assessed as a function of age and gender. The Pearson correlation analysis between SER and ocular biometrics was carried out. Multiple linear regression was performed to analyze the association between SER and ocular parameters. A total of 689 out of 735 participants (321 boys, 48.1%) were analyzed, with a mean SER of -2.98±1.47 diopter (D). Axial length (AL), anterior chamber depth (ACD), corneal radius of curvature (CR), horizontal visible iris diameter (HVID), central corneal thickness (CCT) and lens power (LP) showed normal distribution. The AL, AL/CR ratio, ACD and CR increased from 8 to 12y of age, while SER and LP decreased, HVID and CCT remained stable. There was no difference in gender. SER decreased by 0.929 D for every 1 mm increase in AL and decreased by 1.144 D for every 0.1 increase in AL/CR ratio. The Pearson correlation coefficient between SER and AL was -0.538 (P<0.01) and -0.747 (P<0.01) between SER and AL/CR ratio. For the SER variance, AL explained 29.0%, AL/CR ratio explained 55.7%, while AL, CR, ACD and LP explained 99.3% after adjusting for age and gender. The AL, CR, ACD and LP are the most important determinants of myopic refractive error during myopia progression.

Quantitative and Aesthetic Analysis of Changes in Eyebrow Position After Subbrow Blepharoplasty.

Narrowing of the distance between the eyes and eyebrows is commonly observed after subbrow blepharoplasty. The purpose of this study was to quantify the changes in brow-lid distance after subbrow blepharoplasty in Asian women. We observed and standardized the pre- and postoperative photographs of 63 patients who underwent subbrow blepharoplasty from January 2020 to October 2022. We measured the distances from the medial and lateral eyebrow to the lower lid margin on the right side of the face and then analyzed the changes in postoperative brow-lid distance using the standard iris diameter for Asian women of 11.5mm as a reference. Photographs of 63 patients were included in the study. All 63 patients were females. The average postoperative distance of the lateral eyebrow to the lower lid margin was 30.08 ± 2.74mm, a significant decrease in comparison to the preoperative distance (31.84 ± 2.65mm) (P < 0.001). The mean postoperative distance of the medial eyebrow to the lower lid margin was 25.84 ± 2.87mm, compared with that of the preoperative distance (27.59 ± 2.94mm), which was a significant decrease (P<0.001). All 63 patients (100%) had a decrease in the lateral eyebrow distance, while 59 (93.65%) had a decreased medial eyebrow distance. There was a statistically significant change in brow position, consistent with our observations. Subbrow blepharoplasty can cause a decrease in the distance between the eyebrows and eyes. This journal requires that authors assign a level of evidence to each article. For a full description of these Evidence-Based Medicine ratings, please refer to the Table of Contents or the online Instructions to Authors www.springer.com/00266 .

Facial morphological analysis for the development of a representative atlas of the brazilian population

The objective of this study was to propose categories of morphological classification for the face and its anatomical structures, as well as to propose illustrations to support the development of an atlas that facilitates facial morphological analysis of adult Brazilians. It was a descriptive study based on the analysis of the frequency and distribution of 13 photoanthropometric facial ratios (RFAs) obtained from a representative sample of the Brazilian population. RFAs related to facial height and width, eye width, intercanthal distance, nose length and width, philtrum ridge height and width, mouth thickness and width, upper and lower lip thickness, and chin height were analyzed. The study included a sample of 5.000 individuals aged between 18 and 22 years, evenly distributed between genders. Data normality was assessed using the Shapiro-Wilk test, considering them as parametric when p > 0.05. For the RFAs that showed normal distribution, mean ± 1.5 standard deviations (SD) were used to categorize facial measurements as regular, below average, or above average. Non-parametric RFAs were analyzed based on the median and 10th and 90th percentiles of the data. Based on the established average iris diameter, which is considered the most stable facial measurement, the values of the described RFAs were converted to a numerical scale in centimeters, allowing for the illustration of female and male faces. In this way, it was possible to categorize the facial anatomical structures and, consequently, visualize the facial morphological pattern of the adult Brazilian population.

Normative data of corneal diameter and palpebral fissure height in a large cohort of South Indian children.

The purpose of this study was to establish the normative data of horizontal visible iris diameter (HVID), vertical visible iris diameter (VVID), and palpebral fissure height (PFH) in a cohort of South Indian children. The study included 1,234 children from six schools of different regions of Tamil Nadu state, India. HVID, VVID, and PFH were measured using a simple millimeter ruler by three optometrists. Based on their age, the children were divided into three groups: preprimary school children (4-5 years), primary school children (6-10 years), and high school children (11-15 years). Mean age was 4.49 ± 0.50 years, 8.00 ± 1.41 years, and 12.87 ± 1.42 years in the three groups, respectively. Mean HVID was 10.45 mm, 10.54 mm, and 10.73 mm, respectively. Mean VVID was 9.18 mm, 9.32 mm, and 9.57 mm, respectively. Similarly, mean PFH was 8.15 mm, 8.30 mm, and 8.52 mm, respectively. There was a significant difference in HVID, VVID, and PFH among the three age groups (P ≤ 0.001), as well as among male and female children in the 6-10 years age group (P ≤ 0.05) but not in the other groups. Intraclass correlation coefficient values (0.78-0.95) show good agreement among the three optometrists for all parameters. The normal range of HVID, VVID, and PFH presented in the current study can help practitioners in the diagnosis of corneal disorders, serve as a basis for the design of contact lenses, and enable accurate intraocular lens power calculations for South Indian children.

Measurements of oculo-palpebral landmarks and evaluation of patient's head position.

Keeping the head in a neutral position is requisite for glasses/lenses/head-up designs, the suitability of oculo-plastic surgery and for the grading the eye shift. Anatomically incompatible glasses are one of the common problems affecting accommodation, reducing comfort and disturbing by causing symptoms such as dizziness and nausea. The oculo-palpebral measurements act as a key determinant in symmetrical facial attractiveness. This study aims to investigate the most effective oculo-palpebral landmarks, head-neutral as the ideal position, taking into account of individual anatomical differences of these patients. 100 females and 100 males aged between 18 and 20 years were photographed. Digital photogrammetric measurements were made with the ImageJ program. Interpupillary and interhelical distances, besides bilateral palpebral fissure length and height, and iris diameter were calculated on front-facing photographs. Mean interpupillary distance was measured wider in males than in females. The mean length of palpebral fissure was 31mm; palpebral fissure height was 10mm. These figures were valid in both eyes and gender. The interhelical distance was calculated as the mean and was measured longer in men. Since the measurement values were the same in both sexes and on both sides, they were determined as important landmarks for controlling the head-neutral position, evaluating whether there was a deviation in the eye, and measuring the numerical value when detected. It is essential to check the side-symmetry of the patient's palpebral fissure height, palpebral fissure length, diameter of iris and corneal depth during oculo-plastic invention and artificial design.

Evaluation of the Effect of Inferior Oblique Myectomy on Corneal and Anterior Segment Parameters

Purpose: This study aimed to evaluate the effect of inferior oblique myectomy (IOM) surgery on the cornea and anterior segment. Methods: The sheimpflug corneal topographies of 56 eyes of 33 patients who underwent IOM were analyzed at preoperative, postoperative 1 week, 1 month, 3 months, and 6 months. Astigmatism degree (Cyl), astigmatism axis (Ax), K1, central corneal thickness (CCT), anterior chamber depth (ACD), anterior chamber volume (ACV), iridocorneal angle (ICA), and horizontal visible iris diameter (HVID) were evaluated. Results: The mean corneal Cyl, K1, ICA, ACD, and HVID did not change after IOM (p=0.671, p=0.377, p=0.431, p=0.588, p=0.795, respectively). There was a statistically significant change in Ax (p=0.025). The right Ax decreased, and the left Ax increased the most at 1 month (p=0.025, p=0.882, respectively). Ax increase was also detected in the left eye that was not operated on. The mean CCT increased and mean ACV decreased at 1 month (p=0.588, p=0.270, respectively), but these changes returned to preoperative values at 3 months. Conclusion: The manifestation of anterior segment alterations and intorsion in both eyes following inferior oblique myectomy may contribute to diminished visual acuity and the potential onset of amblyopia. These alterations merit consideration during the assessment, and if deemed necessary, the provision of new spectacles should be considered as a preventive measure against anisometropic amblyopia.

Medmont Meridia™: Much More Than a Corneal Topographer.

In recent years, advanced diagnostic instruments have become widely available in optometric practices, offering various functions that optimize clinical information gathering. This article focuses on the Medmont Meridia™, a state-of-the-art multipurpose diagnostic device with corneal topography and cutting-edge features. Corneal topography is pivotal in the early diagnosis of corneal disorders, determining baseline ocular surface assessment, helping in contact lens fitting, and monitoring ocular health over time. The Medmont Meridia boasts Placido-disc-based imaging with extensive corneal coverage. Furthermore, the Meridia accurately measures the horizontal visible iris diameter, pupil diameter, and palpebral fissure width, which assists in making contact lens parameter decisions. Additionally, it offers sagittal height data for scleral lens design and first lens selection, streamlining the fitting process. Beyond its topography capabilities, the Meridia excels as a comprehensive dry eye assessment tool. With features like tear meniscus height, tear film surface quality, and meibography capabilities, it aids in diagnosing dry eye and monitoring its progression. The device also provides customizable dry eye reports with integrated grading scales and questionnaires, making dry eye management, patient education, and compliance more accessible. In conclusion, the Medmont Meridia consolidates a multitude of examination tools in a single instrument, enhancing practice efficiency and elevating patient care and communication. Its versatility and accuracy make it an invaluable asset in optometric practices worldwide.

A deep learning framework to scale linear facial measurements to actual size using horizontal visible iris diameter: a study on an Iranian population

Digital images allow for the objective evaluation of facial appearance and abnormalities as well as treatment outcomes and stability. With the advancement of technology, manual clinical measurements can be replaced with fully automatic photographic assessments. However, obtaining millimetric measurements on photographs does not provide clinicians with their actual value due to different image magnification ratios. A deep learning tool was developed to estimate linear measurements on images with unknown magnification using the iris diameter. A framework was designed to segment the eyes’ iris and calculate the horizontal visible iris diameter (HVID) in pixels. A constant value of 12.2 mm was assigned as the HVID value in all the photographs. A vertical and a horizontal distance were measured in pixels on photographs of 94 subjects and were estimated in millimeters by calculating the magnification ratio using HVID. Manual measurement of the distances was conducted on the subjects and the actual and estimated amounts were compared using Bland–Altman analysis. The obtained error was calculated as mean absolute percentage error (MAPE) of 2.9% and 4.3% in horizontal and vertical measurements. Our study shows that due to the consistent size and narrow range of HVID values, the iris diameter can be used as a reliable scale to calibrate the magnification of the images to obtain precise measurements in further research.

Development and Assessment of an Artificial Intelligence-Based Tool for Ptosis Measurement in Adult Myasthenia Gravis Patients Using Selfie Video Clips Recorded on Smartphones

Introduction: Myasthenia gravis (MG) is a rare autoimmune disease characterized by muscle weakness and fatigue. Ptosis (eyelid drooping) occurs due to fatigue of the muscles for eyelid elevation and is one symptom widely used by patients and healthcare providers to track progression of the disease. Margin reflex distance 1 (MRD1) is an accepted clinical measure of ptosis and is typically assessed using a hand-held ruler. In this work, we develop an AI model that enables automated measurement of MRD1 in self-recorded video clips collected using patient smartphones. Methods: A 3-month prospective observational study collected a dataset of video clips from patients with MG. Study participants were asked to perform an eyelid fatigability exercise to elicit ptosis while filming “selfie” videos on their smartphones. These images were collected in nonclinical settings, with no in-person training. The dataset was annotated by non-clinicians for (1) eye landmarks to establish ground truth MRD1 and (2) the quality of the video frames. The ground truth MRD1 (in millimeters, mm) was calculated from eye landmark annotations in the video frames using a standard conversion factor, the horizontal visible iris diameter of the human eye. To develop the model, we trained a neural network for eye landmark detection consisting of a ResNet50 backbone plus two dense layers of 78 dimensions on publicly available datasets. Only the ResNet50 backbone was used, discarding the last two layers. The embeddings from the ResNet50 were used as features for a support vector regressor (SVR) using a linear kernel, for regression to MRD1, in mm. The SVR was trained on data collected remotely from MG patients in the prospective study, split into training and development folds. The model’s performance for MRD1 estimation was evaluated on a separate test fold from the study dataset. Results: On the full test fold (N = 664 images), the correlation between the ground truth and predicted MRD1 values was strong (r = 0.732). The mean absolute error was 0.822 mm; the mean of differences was −0.256 mm; and 95% limits of agreement (LOA) were −0.214–1.768 mm. Model performance showed no improvement when test data were gated to exclude “poor” quality images. Conclusions: On data generated under highly challenging real-world conditions from a variety of different smartphone devices, the model predicts MRD1 with a strong correlation (r = 0.732) between ground truth and predicted MRD1.

Prediction model of the horizontal trabecular iris angle after phakic posterior chamber implantable intraocular lens surgery.

To determine the predictors of the postoperative horizontal trabecular iris angle (TIA750) after phakic posterior chamber implantable intraocular lens (IOL) surgery. Ophthalmology Clinic Vista Sánchez Trancón. Retrospective case series. This study included 330 eyes implanted with spherical/toric Implantable Collamer Lens (ICL). From 230 eyes implanted with 13.2 mm ICL, these were divided in modelling (n=180) and evaluation group (n=50). Two groups implanted with 12.6 and 13.7 mm (n=50 each) were also used as evaluation. Anterior-segment OCT was used preoperatively to perform anterior chamber biometry (angle-to-angle distance (ATA), crystalline lens rise (CLR), anterior chamber depth (ACD), cornea sagittal depth, pupil diameter, nasal/temporal TIA750; postoperatively for measuring the vault, pupil diameter and nasal/temporal TIA750. Corneal curvature and horizontal visible iris diameter were measured using optical tomography. Bivariate correlation analysis was used to determine associations between preoperative and postoperative horizontal TIA750 with anterior chamber biometry, ICL-related parameters and age. Finally, a multivariate linear regression model (MLR) was constructed for predicting the postoperative TIA750. Horizontal TIA750 reduced from 42.9±8.0 degrees preoperatively to 24.4±5.6 degrees postoperatively. Postoperative TIA750 was positively correlated with the preoperative TIA750, cornea sagittal depth and ACD, and negatively associated with the vault. The main predictors of the postoperative TIA750 were the preoperative parameters, TIA750, ICLsize - ATA and pupil diameter (adjusted-R2=0.39). The limits of agreement between predicted and real TIA750 were close to ±10 degrees. Implantation of a phakic posterior chamber implantable IOL leads to a reduction in TIA750 and the main factors contributing for this are the preoperative TIA750 aperture and the vault.

Soft contact lens options in the management of pediatric aphakia – A quantitative and qualitative assessment

BackgroundThe main contact lens for pediatric aphakia has historically been a silicone elastomer lens (Silsoft SuperPlus). Due to supply chain disruption, many aphakic children required an alternative lens. We performed quantitative and qualitative comparisons between Silsoft SuperPlus and alternative aphakic soft contacts. MethodSixty-nine aphakic eyes of 49 patients wearing Silsoft SuperPlus lenses underwent the refitting process into an alternative soft contact. Data collected included lens parameters, visual acuity, keratometry, horizontal visible iris diameter, and over-refraction. A 6-question survey assessing the patients’/guardians’ experience with Silsoft SuperPlus versus the alternative lens was conducted at initial fit and 1–3 months post-fit. ResultsTwenty-four patients (49 %), 4(8 %), and 1(2 %) were refit into Flexlens Definitive 74, Biofinity XR, and Intelliwave Pro Toric lenses, respectively. Sixteen patients (34 %) remained in Silsoft SuperPlus due to personal lens surplus or inability to handle the new lens while 2(4 %) opted for glasses. Silsoft SuperPlus was typically successful in eyes with average keratometry (AveK) 7.4–7.6 mm. Flexlens Definitive 74 required a base curve 0.4 mm steeper than the AveK. Patients’/guardias' reported a trend toward greater comfort with handling Silsoft SuperPlus, however, patients experienced less adverse side effects with the alternative soft contact lenses. ConclusionsFlexlens Definitive 74 was an adequate alternative to Silsoft SuperPlus in aphakic children, however lens parameters must be steepened. Keratometry streamlined the contact lens fitting process. Alternative soft lenses are a cost-effective alternative to Silsoft contact lenses.

Improvement in the ideal range of vault after implantable collamer lens implantation: a new vault prediction formula.

To derive and validate a novel vault prediction formula to improve the predictability and safety of implantable collamer lens (ICL) implantation. Thirty-five patients (61 eyes) with previous posterior chamber intraocular lens implantation were included. Various parameters, such as horizontal-visible iris diameter (HVID), photopic pupil diameter (PPD), axial length (AL), white-to-white (WTW), anterior chamber width (ACW), angle-to-angle (ATA), crystalline lens rise (CLR), anterior chamber depth (ACD), horizontal sulcus-to-sulcus (HSTS), and ciliary sulcus angle (CSA) were measured. Vault was measured at 3 months after surgery using CASIA2 anterior segment optical coherence tomography. The formula was derived using multiple linear regression analysis and named as WH formula. It was validated in 65 patients (118 eyes) to determine the percentage of the ideal postoperative vault range and to compare the differences between the WH formula and the NK, KS, and STAAR formulas. Final ICL size, ATA, CSA, and CLR were included in the prediction formula model (adjusted R2 = 0.67, p < 0.001). The achieved vault 1 month after the surgery was 556.19 μm ± 166.98 μm in the validation group, and the ideal vault range was 200-800 μm (92%). The difference between the achieved vault and that predicted using the WH formula was not statistically significant (p = 0.165), whereas the difference between the achieved vault and that predicted using the NK and KS formulas was statistically significant (p < 0.001 and p < 0.001, respectively). The 95% agreement limit range of the achieved vault and the vault predicted using the WH formula was narrower than those predicted using the NK and KS formulas (-295.20-258.82 μm). This study combined the results of optical coherence tomography and ultrasound biomicroscopy measurements of the anterior segment of the eye and incorporated ciliary sulcus morphology quantification into the prediction formula. The study derived a prediction formula for vault by combining ICL size, ATA, and CLR. The derived formula was found to be superior to the currently available formulas.

Commentary: Reliability, repeatability, and accuracy of Sirius topographer in assessing anterior segment morphology following laser peripheral iridotomy in primary angle-closure disease.

Commentary: Reliability, repeatability, and accuracy of Sirius topographer in assessing anterior segment morphology following laser peripheral iridotomy in primary angle-closure disease.

Development and Validation of a Simple Nomogram for Predicting Rapid Myopia Progression in Children with Orthokeratology Management

Purpose To develop and validate an ideal nomogram and an online calculator for predicting rapid myopia progression risk in children managed with orthokeratology (ortho-k). Methods Data of children undergoing ortho-k treatment at Shanghai Children’s Hospitals between January 2018 and April 2021 were retrospectively assessed. Potential predictors were screened using univariable analyses and a bidirectional stepwise procedure based on Akaike’s information criterion. The final model was constructed using multivariable logistic regression and validated using an internal validation cohort. A nomogram and an online calculator were used to present the final model. Results In this retrospective study with 1051 eyes of 560 myopia patients, the training cohort included 735 eyes, and the validation cohort included 316 eyes. Among 11 potential predictors of rapid myopia progression considered, the following four variables identified as independent predictive factors were included in the nomogram: age (odds ratio [OR], 0.69; 95% confidence interval [CI], 0.61–0.79), baseline spherical equivalent (OR, 1.53; 95% CI, 1.31–1.79), pupil diameter (OR, 0.56; 95% CI, 0.32–0.97), and horizontal visible iris diameter (OR, 0.57; 95% CI, 0.33–0.97). The mean concordance statistics for the training and validation cohorts were 0.705 (95% CI 0.664–0.747) and 0.707 (95% CI 0.639–0.774), respectively. The online calculator is publicly available (https://hycalculatoronline.shinyapps.io/dynnomapp/). Conclusion This study developed a simple-to-use nomogram and online calculator that predicted rapid myopia progression risk in children treated with ortho-k, who will likely benefit from early intervention and improved surveillance.

Repeatability and agreement of swept-source optical coherence tomography and partial coherence interferometry biometers in myopes

ABSTRACT Clinical relevance Biometric measurements in the context of myopia are fundamental to detect eyes at risk of developing myopia and during the follow-up of patients with myopia control treatment. Thus, the accuracy of biometers has high clinical relevance. Background The Myopia Master is a new biometer based on partial coherence interferometry especially dedicated to the follow-up of myopic patients. This study aims to assess the repeatability of the Myopia Master and evaluate its agreement with a swept-source optical coherence interferometry biometer (IOL Master 700). Methods This cross-sectional prospective study assessed the biometric parameters of two groups of myopes (age range: 8–16 years old), spectacle corrected (n = 60) and orthokeratology contact lens wearers (n = 60). One senior optometrist performed two consecutive measurements per instrument, which included axial length, mean keratometry and horizontal visible iris diameter (HVID). The repeatability of each device and the agreement between devices were assessed by the dispersion of the measurement differences, for AL, mean keratometry, corneal astigmatism and HVID. Results The two biometers measured approximately the same value in both measurements. Test–retest repeatability tended to be lower than clinical significant thresholds, in particular, for AL and mean keratometry. Corneal-related parameters tended to have lower repeatability in the orthokeratology group, especially mean keratometry. The agreement between instruments revealed statistically significant differences between devices with the SS-OCT measuring longer eyes, steeper corneas and larger HVID. Conclusions In a paediatric population, the Myopia Master showed clinically acceptable repeatability levels, but the IOL Master 700 demonstrated superior repeatability. Eyes treated with orthokeratology may compromise the repeatability of the corneal-related parameters. The Myopia Master and the IOL Master 700 are repeatable devices appropriate for monitoring myopia progression, but the differences observed do not allow their use interchangeably.

Mask_LaC R-CNN for measuring morphological features of fish

In aquaculture management, the measurement of various morphological characteristics of fish, such as body length, body width, caudal peduncle length and width, pupil diameter and iris diameter, are the main information basis for breeders to feed, use drugs, catch, grade and make breeding characters analysis. Obtaining these information quickly and accurately can provide effective guidance for management and control in the aquaculture process, and it is conducive to improve production efficiency and increase income. By combining data expansion method and Mask_LaC R-CNN network, this paper realizes the accurate measurement of various morphological characteristics of fish, and design a non-contact measurement system of fish morphological parameters. Because the fish position and image contrast in the data set are too single, data expansion method such as shrinkage transformation, translation transformation, contrast transformation and adding noise are used to simulate a more real scene. For the loss function of Mask R-CNN, smooth L1 loss is improved by using the balanced L1 loss function; the convolution decomposition is used to realize the lightweight network structure, so that the model can accelerate the network while maintaining high accuracy. At the same time, the hole convolution can effectively improve the accuracy of the detection algorithm without additional parameters and computational cost. The enhanced data set and the Mask_LaC R-CNN experiment shows that the improved scheme improves the measurement accuracy. Under the pure background, the mIoU of 50 test images is 0.930, the relative error of body length is 1.46%, and the relative error of body width is 0.65%. Under the complex background, the mIoU of 50 test images is 0.934, the relative error of body length is 6.98%, and the relative error of body width is 8.05%.

Distribution of angle lambda and pupil offset as measured by combined Placido Scheimpflug Topography

BackgroundAngle lambda is the angle between the pupillary axis and the line of sight. It is important for accurate centration during anterior segment surgery. The purpose of this study is to identify the distribution of angle lambda and pupil center offset as measured by a combined placido disc Scheimpflug topography system.MethodsA prospective non-randomized study was performed on 2178 eyes in Eye World Hospital, Giza, Egypt. Sirius device (CSO, Costruzione Strumenti Oftalmici, Florence, Italy, version 3.2.1.60) was used to measure average keratometry (K), anterior chamber depth (ACD), central corneal thickness (CCT), horizontal visible iris diameter (HVID), pupil radius (PR), pupil center intercept x-component (PCI-x), and pupil center intercept y-component (PCI-y). Axial length (AL) was measured by immersion A-scan Eyecube Ultrasonography device (Ellex, Adelaide, South Australia, Australia). Angle lambda was calculated by a trigonometrical equation. Pearson correlation was used to analyze the correlation between angle lambda and age and refraction.ResultsAverage angle lambda in all eyes was 3.32° ± 1.99. Mean angle lambda was significantly smallest in myopia and largest in hyperopia. Age correlation to angle lambda was insignificant. Average PCI-x and PCI-y in all eyes was − 0.047 mm and + 0.091 mm, respectively.ConclusionsAngle λ is significantly larger in hyperopia than myopia, and the effect of age is insignificant. Pupil center offset was horizontally greater in hyperopia than in myopia. We therefore encourage the preoperative assessment of angle λ to avoid decentered ablation, especially when treating hyperopia.

Video-Based Eye Blink Identification and Classification.

Blink detection and classification can provide a very useful clinical indicator, because of its relation with many neurological and ophthalmological conditions. In this work, we propose a system that automatically detects and classifies blinks as "complete" or "incomplete" in high resolution image sequences zoomed into the participants' face, acquired during clinical examination using near-Infrared illumination. This method utilizes state-of-the-art (DeepLabv3+) deep learning encoder-decoder neural architecture -DLED to segment iris and eyelid in both eyes in the acquired images. The sequence of the segmented frames is post-processed to calculate the distance between the eyelids of each eye (palpebral fissure height) and the corresponding iris diameter. These quantities are temporally filtered and their fraction is subject to adaptive thresholding to identify blinks and determine their type, independently for each eye. The proposed system was tested on 15 participants, each with one video of 4 to 10 minutes. Several metrics of blink detection and classification accuracy were calculated against the ground truth, which was generated by three (3) independent experts, whose conflicts were resolved by a senior expert. Results show that the proposed system achieved F1-score 95.3% and 80.9% for the classification of complete and incomplete blinks respectively, collectively for all 15 participants, outperforming all 3 experts. The proposed system was proven robust in handling unexpected participant movements and actions, as well as glare and reflections from the spectacles, or face obstruction by facemasks.

Validity of Horizontal Iris Dimension as a predictor of Denture Esthetics in Melmaruvathur population

Esthetics is of utmost importance for a complete Denture seeker and maxillary anterior teeth play a pivotal role in denture esthetics. No study exists till date regarding the use and reliability of any anatomical landmark to assess the size of maxillary central incisors for edentulous patients of Melmaruvathur, Tamil Nadu, India. Horizontal visible iris diameter (HVID) has been correlated positively with central incisor dimensions photogrammetrically. The purpose of this study is to explore the potential role of HVID of the eye in the central incisor dimensions in the residents of a specified geographical location and revalidate the role of HVID in anterior teeth selection.

Efficacy of fitting HydroCone (Toris K) contact lenses for the visual rehabilitation of patients with posterior microphthalmos.

To evaluate the efficacy of soft HydroCone silicone hydrogel contact lenses in patients with posterior microphthalmos. The charts of 13 patients with posterior microphthalmos (26 eyes) who were fitted with soft HydroCone silicone hydrogel contact lenses were reviewed retrospectively. All the patients underwent assessments of uncorrected and best spectacle-corrected visual acuity and cycloplegic refraction. They were fitted with contact lenses according to the parameter values obtained from the topographical analysis and best contact lens-corrected visual acuity measurement. The spherical equivalents of the right and left eyes ranged from 10.00 to 19.25 diopters and from 11.00 to 21.5 diopters, respectively. The mean axial and posterior chamber lengths were shorter than those of the age-matched population. However, the mean values of the anterior segment parameters such as horizontal visible iris diameter, central anterior chamber depth, lens thickness, and central corneal thickness were in the normal range. The mean keratometric measurements revealed increased corneal curvature compared with that in the normal population. The mean best contact lens-corrected visual acuity was significantly higher than the mean best spectacle-corrected visual acuity for both eyes (p=0.045). HydroCone silicon soft contact lenses provided better visual acuity than spectacles in the patients with posterior microphthalmos in this study.