Pupil Area Research Articles

Pupil Status with Low-Energy Femtosecond Laser-Assisted Cataract Surgery versus Conventional Phacoemulsification: An Intraindividual Comparative Study.

To compare the pupil changes in low-energy femtosecond laser-assisted cataract surgery (FLACS) with conventional phacoemulsification (CP) intraindividually. A retrospective review of registered surgical data from patients that undergone uncomplicated cataract surgery in a single centre, with randomly assigned femtosecond laser-assisted cataract surgery (FLACS) to one eye and conventional phacoemulsification (CP) to the other, was performed. The recorded pupil images were evaluated at pre and post laser treatment (after suction release) and at several surgical timepoints for both techniques (FLACS and CP). Pupil areas were calculated and compared in the same eye undergone FLACS (pre vs post laser treatment), between eyes (CP vs FLACS) in the same patient and between groups. Subgroups were built regarding age and ocular comorbidity. This study involved a total of 164 eyes of 82 patients (55 female, 27 male). No statistical differences regarding the total duration of surgery (p=0.805) between FLACS and CP. Pupil measurements between pre and post laser treatment in the FLACS group showed no statistically significant differences (p=0.107). The mean change in pupil area from the beginning until the end of surgery (total variation) was 6.59±2.08 mm2 in the FLACS group and 6.67±2.13 mm2 in the CP group, associated to less narrowing of pupil area with FLACS, although not statistically significant (p=0.080). Comorbidity group analysis revealed less, but not significant, pupil narrowing with the FLACS technique (p=0.071). No statistically significant differences between FLACS and CP concerning age subgroups were registered. This study shows no significant pupil changes, namely myosis, after low-energy FLACS pre-treatment. Comparison between techniques showed less pupil variation in FLACS as compared to CP, more markedly in eyes with comorbidities (particularly with shallow anterior chamber), although non-statistically significant.

Atypical Presentation of Recurrent Pterygium Leading to Blindness and its Successful Management: A Series of Three Cases

Recurrence of pterygium is one of the main concerns in pterygium management. Recurrent pterygium is defined as the regrowth of fibrovascular tissue over the previously excised primary pterygium area, extending beyond the limbus and advancing towards the cornea. In most cases, it is characterised by increased conjunctival inflammation, fibroblast proliferation, and a faster progression towards corneal involvement compared to primary pterygium. This rapid regrowth can lead to irregular astigmatism, symblepharon, corneal fibrosis, severe vision impairment, and rarely, blindness. Incomplete removal of the primary pterygium, excessive suturing, the bare sclera technique, smaller conjunctival grafts, thicker conjunctival grafts with Tenon’s capsule, and poor control of postoperative inflammation are some of the most common surgical factors contributing to recurrence. Among all surgical procedures, the bare sclera technique has the highest recurrence rate. In the present case series, the author presented three cases of atypical recurrent pterygium and their successful management. The first case involved recurrent double-headed pterygium with severe symblepharon, resulting in lower fornix obliteration, shortening, diplopia, and corneal neovascularisation. The second case featured Grade-IV pterygium covering the pupillary area, and the third case involved a kissing type of doubleheaded pterygium. These cases were complications of the bare sclera technique, leading to blindness. Successful treatment of recurrent pterygium can improve visual and cosmetic outcomes. This case series aimed to highlight the burden and consequences of recurrent pterygium as a cause of avoidable blindness.

Detection of Driver Cognitive Distraction Using Machine Learning Methods

Driver distraction is one of the primary causes of crashes. As a result, there is a great need to continuously observe driver state and provide appropriate interventions to distracted drivers. Cognitive distraction refers to the “look but not see” situations when the drivers’ eyes are focused on the forward roadway, but their mind is not. Typically, cognitive distractions can result from fatigue, conversation with a co-passenger, listening to the radio, or other similarly loading secondary tasks that do not necessarily take a driver’s eyes off the roadway. This makes it one of the hardest distractions to detect as there are no visible clues of driver distraction. In this study, we have identified features from different sources including eye-tracking, physiological, and vehicle kinematics data that are relevant towards the classification of distracted and non-distracted drivers via the analysis of data collected from a driving simulator study involving 40 drivers across multiple driving scenarios. The key classification algorithms implemented include Random Forest, Decision Trees and Support Vector Machines. A reduced feature set including pupil area, pupil vertical and horizontal motion was found to be predictive of driver distraction while maintaining an average accuracy of 90% across various road types. Additionally, the impact of road types on driver behaviour was also identified. The findings of the study has practical application towards the design of driver distraction monitoring systems.

The influence of dimming-induced luminance change on driving safety in tunnels

Although dimming the light in tunnels brings salient benefits to energy saving, the effects of dimming-induced luminance changes on driving safety have been rarely explored. Adopting the visual performance experiment, the present study investigated the impacts of the dimming-induced luminance change rate (V) on the safety of driver’s perception, judgment, and operation in the threshold zone of the tunnel under different seasons and weather conditions. The results show that the reaction times (RTs), pupil area change rate (vp), and blink frequency (fb), increased with the increase of V. When the luminance before the beginning of dimming (L) was higher, drivers reacted faster and stood a lower level of the mental load and fatigue. Compared with decreasing the luminance through dimming, when increasing the luminance through dimming, the present study found that each of the visual performance indices was about 10% lower, and the changes with V became smaller. Based on the safety thresholds of RT, vp, and fb, the present study obtained the thresholds of V which can meet the safety requirements of driver’s perception, judgment, and operation. Finally, a theoretical model between the thresholds of V and L was developed, and this model will shed light on the control of V in the threshold zone of the tunnel under different seasons and weather conditions.

Nystagmus patterns classification framework based on deep learning and optical flow

Benign paroxysmal positional vertigo (BPPV) is the most common vestibular peripheral vertigo disease characterized by brief recurrent vertigo with positional nystagmus. Clinically, it is common to recognize the patterns of nystagmus by analyzing infrared nystagmus videos of patients. However, the existing approaches cannot effectively recognize different patterns of nystagmus, especially the torsional nystagmus. To improve the performance of recognizing different nystagmus patterns, this paper contributes an automatic recognizing method of BPPV nystagmus patterns based on deep learning and optical flow to assist doctors in analyzing the types of BPPV. Firstly, we present an adaptive method for eliminating invalid frames that caused by eyelid occlusion or blinking in nystagmus videos and an adaptive method for segmenting the iris and pupil area from video frames quickly and efficiently. Then, we use a deep learning-based optical flow method to extract nystagmus information. Finally, we propose a nystagmus video classification network (NVCN) to categorize the patterns of nystagmus. We use ConvNeXt to extract eye movement features and then use LSTM to extract temporal features. Experiments conducted on the clinically collected datasets of infrared nystagmus videos show that the NVCN model achieves an accuracy of 94.91% and an F1 score of 93.70% on nystagmus patterns classification task as well as an accuracy of 97.75% and an F1 score of 97.48% on torsional nystagmus recognition task. The experimental results prove that the framework we propose can effectively recognize different patterns of nystagmus.

Capturing Luminous Flux Entering Human Eyes with a Camera, Part 1: Fundamentals

ABSTRACT A space occupant’s real-time exposure to light reaching his/her eyes has been a concern in lighting research and design practice. This study assumed a schematic eye to estimate the luminous flux received by the entrance pupil from the visible luminous environment. As the first part of this study, this paper focused on the fundamentals of luminous flux calculation that considers real-time human eye reactions. The research work includes: (a) developing a dynamic binocular/monocular visual field model that takes the eye movement into account, based on a conventional visual field model in orthomode, (b) retrieving the apparent area of the entrance pupil of the schematic eye, and (c) quantifying the light passing through the entrance pupil from the luminous environment fallen in the binocular/monocular visual field. The fundamental theory was tested in a theoretical uniform lighting scene to calculate the luminous flux emitted from the human visual field along multiple gaze directions at different light levels. A foundation was thus laid to estimate the real-time luminous flux passing through the entrance pupil with the aid of the camera as disclosed in Part 2 of the present study.

Studying Driver’s Perception Arousal and Takeover Performance in Autonomous Driving

The driver’s perception level and takeover performance are two major factors that result in accidents in autonomous vehicles. This study’s goal is to analyze the change in drivers’ perception level and its influence on takeover performance during autonomous driving. A takeover behavior test platform is implemented based on a high-fidelity driving simulator. The fog zone is selected as the takeover scenario. Thus, a 2 (takeover request time: 5 s, 10 s) by 2 (non-driving-related task: work task, entertainment task) takeover experiment was conducted. A generalized linear mixed model is developed to explore the influence of the perception level on takeover performance. The study finds out that, after the takeover request is triggered, the driver’s gaze duration is shortened and the pupil area is enlarged, which is helpful for the driver to extract and understand the road information faster. Male drivers have greater perception levels than female drivers, and they prioritize leisure tasks more than professional ones. The drivers’ perception level decreases when age increases. The shorter the gaze duration is, and the larger the pupil area is, the shorter the takeover response time will be. In addition, drivers’ perception level has a positive effect on takeover performance. Finally, this study provides a reference for revealing the changing rules of drivers’ perception level in autonomous driving, and the study can provide support for the diagnosis of takeover risks of autonomous vehicles from the perspective of human factors.

The first cataract extraction operations

Abstract.The first written record of cataract surgery dates back to 2250 BC, when King Hammurabi of Babylon created a law regarding the outcome of cataract surgery. The first detailed description of cataract surgery was written by an Indian ophthalmologist Maharishi Sushruta in the sixth century BC. Sushruta performed the first couching - reclining operations. "Couching" means that the blurred lens is embedded in the vitreous, or fundus of the eye. At that time, because the scientists had no idea about the structure of the lens and the pathogenesis of the cataract, they believed that the cataract was a membrane in the pupil area and tried to cut it. They wanted to enter the anterior camera with a sharp instrument and tear the "membrane". In the 10th century AD, the Iraqian ophthalmologist Ammar Al-Mawsili began using a new method in cataract surgery - the "suction" method. Ammar Al-Mawsili was the first to say that cataract is blurring of the lens. Ammar ibn Ali Al-Mawsili first invented a hollow thin metal needles with sharp points for syringes. Through that needle, Ammar entered the eye through the sclera behind the limbus and suctioned out the contents of the soft cataract. These operations performed by Ammar Al-Mawsili are considered to be the first successful extraction operations in the history of ophthalmology. In 1748, Jacques Daviel made a right-sided widely corneal incision, passed through the pupil with a small spatula, and extracted the lens from the posterior chamber. CONCLUSION. Cataract extraction, that is, operations based on removing the clouded lens from the eye rather than destroying it inside the eye, was first performed by Ammar ibn Ali Al-Mosuli. Today's cataract surgery is based on Jacques Daviell's extraction technique. But as modern ophthalmology advances, the ultimate goal of ophthalmic surgeons is to reduce the size of the incision for removing the cloudy lens to the size of a needle tip. This means that cataract surgery has progressed from the Daviel technique to the Ammar technique.

Refractive management of a bilateral lens subluxation case in marfan syndrome patient

AbstractPurpose: To report refractive management of bilateral lens subluxation case in Marfan Syndrome patient.Methods: Diagnosis based on a history‐taking, a physical examination, and an ancillary test. The refractive state of the patient was examined by an autorefractometer, streak retinoscopy and best‐corrected visual acuity (BCVA), before and after cycloplegic on each eye.Results: A 7‐years‐old girl diagnosed with Marfan Syndrome by the Department of Paediatric Cardiology complained for blurred vision in both eyes. Initial visual acuity of the patient was 0.027 in her right and left eyes. Anterior segment examination showed phacodenesis in both eyes. After cycloplegic refraction with enlarging pupil diameter and performed streak retinoscopy, BCVA in the right eye was 0.040 with a refractive correction of −22.00 diopters (D) and left eye was 0.021 with −20.00 D. After several follow ups, the refractive state remains highly fluctuates due to severe lens subluxation degree, which is seen through a half pupillary area. Consequently, operative approach using intracapsular lens extraction technique is considered. A month after the surgery, the distance visual acuity in right eye was 0.125 and 0.080 in left eye. With a refractive correction of +5.50 D, visual acuity became 0.500, while for the left eye became 0.125 with +5.00 D. Whereas, binocular distance visual acuity with refractive correction became 0.400. Therefore, spectacle was prescribed to achieve optimal visual acuity.Conclusions: The refractive management steps in lens subluxation associated with Marfan Syndrome case is very challenging depends on patient's condition. The intracapsular lens extraction procedure prior to spectacle prescription should be considered as a management of severe lens subluxation in patient with Marfan syndrome, in order to achieve BCVA.

Vision With Retrodots and Factors for Declining Visual Function.

We investigated decline in the visual function of eyes with retrodots (RDs)-a subtype of cataract. This study included 57 eyes with RD opacity only (mean age 72.3 ± 5.2 years) and 34 eyes with transparent lenses (mean age 71.4 ± 3.7 years). A physician diagnosed lens opacity. Using the Kanazawa Medical University Classification and Grading System, the eyes were classified into the RD-1 (37 eyes, RDs <25% of the 3-mm pupil area) and RD-2 (20 eyes, RDs ≥25% of the 3-mm pupil area) groups. Corrected distance visual acuity, contrast visual acuity, ocular refractive power, lens power, straylight, and backward light-scattering intensity and their relationship with visual function decline and optical characteristics of the eyeball were evaluated. Corrected distance visual acuity was significantly lower in the RD eyes than in controls. Contrast visual acuity decreased significantly in the RD-2 eyes in all environments and in the RD-1 eyes in the evening (EVE) and EVE + glare. Straylight was significantly higher in the RD-2 eyes than in the controls and RD-1 eyes but not different between the RD-1 eyes and controls. The RD-2 eyes were significantly more myopic than the controls and RD-1 eyes. When the opacity of RD eyes is ≥25%, the visual acuity and contrast visual acuity decrease and straylight increases. Furthermore, myopia occurs as the refractive power of the lens increases. Moreover, visual function decline may be due to an increase in the straylight value, which is necessary for determining surgical indications.

Gaming for Training Voluntary Control of Pupil Size

Users can “voluntarily” control the size of their pupil by switching focus from a far target A (large pupil size) to a near target B (small pupil size), according to the pupillary accommodative response (PAR). Pupil size is governed by smooth muscles and has been suggested as communication pathway for patients affected by paralysis of skeletal muscles, such as in amyotrophic lateral sclerosis (ALS). We here present a video game that relies on PAR: a 2d side-scroller game where the user, by varying pupil size, controls the height at which a spaceship is moving aiming at colliding with bubbles to burst them and score points. The height at which the spaceship flies inversely depends on pupil area. The game is implemented on a Raspberry Pi board equipped with a IR camera and may record the time course of pupil size during the game, for off-line analysis. This application is intended as a tool to train and familiarize with the control of pupil size for alternative augmentative communication.

Design of an ellipsoidal mirror assisted oblique plane microscopy

Using one objective for excitation and detection simultaneously, oblique plane microscopy (OPM) provides a mounting-friendly approach for optical sectioning. Unfortunately, the original OPM has three major defects: the mechanical constraints when placing the objectives, the phase loss and the resulting anisotropy of the point spread function (PSF). In order to alleviate the above defects, an ellipsoidal mirror assisted oblique plane microscopy (EM-OPM) was proposed. By inserting an ellipsoidal mirror into the optical path to help collect the light beam, the problem of placing the objectives was solved. The numerical calculation results showed that EM-OPM can obtain higher relative light intensity and larger effective area of exit pupil than OPM when the tilt angle of the light sheet becomes larger. The imaging simulation results showed that EM-OPM effectively solves the problem of resolution reduction in the Y direction of OPM. In addition, optimization of the higher-order terms of the ellipsoidal mirror further improved the imaging ability of EM-OPM in large field of view (FOV).

α-opic flux models based on the five fundus photoreceptors for prediction of light-induced melatonin suppression

Light is effective to suppress the melatonin and affects the non-visual responses. The relationship between light conditions and melatonin suppression is significant when designing light environments. Based on the α-opic illuminances of five fundus photoreceptors, various previous models are built to fit and predict the experimental melatonin suppression. In this study, we present models based on α-opic fluxes, which are products of α-opic illuminances and pupil areas, to improve the fitting results of the experimental melatonin suppression. For 30- and 90-min light exposures, the α-opic flux models present higher adjusted R-squared and lower root mean square of error (RMSE) when fitting the experimental melatonin suppression, regardless of pupil dilation or not. The α-opic flux models also explain the spectral opponency on melatonin suppression. According to the residuals between predicable and experimental melatonin suppression, the effects of pupil dilation, type of light source, and subject's age are further discussed. The subject's age has little effect on the melatonin suppression. The α-opic flux models decrease the fitting residuals under different conditions, improving the applicability of the fitting models on melatonin suppression.

Effect of Pupil Size on Fixed-Luminance Flicker Full-Field Electroretinogram Magnitude.

Diopsys® NOVA fixed-luminance flicker full-field electroretinogram (ffERG) device is a potential adjunct to conventional flicker ffERG testing for assessing cone cell function. Magnitude of measured electrical response is known to vary with pupil size in conventional ffERG testing. The index study characterizes the relationship between magnitude of measured electrical activity and pupil size, both pupil diameter and pupil area, for this device. Seventeen patients (34 eyes) with no known ocular diseases were enrolled in the study. Electrophysiologic function of cone cells was evaluated using fixed-luminance flicker ffERG before and after dilation. Linear regression models, with inter-eye correlations controlled as fixed-effects, were used to characterize the effect of pupil dilation on the magnitude of the measured responses. Mean age of study patients was 33.5 (standard deviation 7.4 years), and 35.3% of the subjects were female. Mean value of electrical response magnitude was 10.07±2.79µV before dilation and 15.30±4.08µV after dilation. The correlations of ERG magnitude with pupil diameter and with pupil area were not significant for either dilated or undilated eyes considered separately but were highly significant (p<0.001) for dilated and undilated eyes considered in aggregate. ERG magnitude tended to increase by 1.08 µV for every 1 mm increase in pupillary diameter. An increase in pupil size, both pupil diameter and pupil area, is significantly associated with an increase in flicker ffERG magnitude recorded by the Diopsys device, suggesting that pupil size should be measured and considered when making clinical judgments based on the flicker ffERGs recorded by the device, and that pupil size-specific reference ranges could improve the clinical utility of the device.

An effective model for the iris regional characteristics and classification using deep learning alex network

Iris biometrics is one of the fastest-growing technologies, and it has received a lot of attention from the community. Iris-biometric-based human recognition does not require contact with the human body. Iris is a combination of crypts, wolflin nodules, concentrated furrows, and pigment spots. The existing methods feed the eye image into deep learning network which result in improper iris features and certainly reduce the accuracy. This research study proposes a model to feed preprocessed accurate iris boundary into Alexnet deep learning neural network-based system for classification. The pupil centre and boundary are initially recorded and identified from the given eye images. The iris boundary and the centre are then compared for the identification using the reference pupil centre and boundary. The iris portion, exclusive feature of the pupil area is segmented using the parameters of multiple left-right point (MLRP) algorithms. The Alexnet deep learning multilayer networks 23, 24, and 25 are replaced according to the segmented iris classes. The remaining Alexnet layers are trained using the square gradient decay factor (GDF) in accordance with the iris features. The trained Alexnet iris is validated using suitable classes. The proposed system classifies the iris with an accuracy of 99.1%. The sensitivity, specificity, and F1-score of the proposed system are 99.68%, 98.36%, and 0.995. The experimental results show that the proposed model has advantages over current models.

Tonic and phasic effects of reward on the pupil: implications for locus coeruleus function.

The locus coeruleus (LC), a nucleus in the pons of the brainstem, plays a significant role in attention and cognitive control. Here, we use an adapted auditory oddball paradigm and measured the pupil dilation response, to provide a marker of LC activity in humans. In Experiment 1, we show event-related pupil responses to rare auditory events which were further elevated by task relevant. In Experiment 2, by asking participants to silently count the number of oddballs, we demonstrated that the task-relevance elevation was not a result of the generation or execution of the manual response. In Experiment 3, we observed two separate effects of reward on the pupil response. First, we found an overall increase in pupil area in the high compared to the low-reward blocks: a sustained effect reminiscent of the tonic changes that occur in LC. Second, we found elevated event-related pupil responses to behaviourally relevant stimuli in the high-reward condition compared with the low-reward condition, consistent with phasic changes in LC in response to a stimulus. These results highlight the complexity of the relationship between the pupil response and reward, and the inferred role of LC in both top-down and bottom-up cognitive control.

The effect of back optic zone diameter on relative corneal refractive power distribution and corneal higher-order aberrations in orthokeratology

PurposeTo compare axial elongation, relative corneal refractive power (RCRP) distribution within the pupillary diameter, and corneal higher-order aberrations (HOAs) in myopic children wearing orthokeratology (ortho-k) lenses with different back optic zone diameters (BOZD). MethodsChildren aged 8–11 years were fitted with 5.0 or 6.2 mm-BOZD ortho-k lenses (groups A and B, respectively). Axial length (AL) and corneal topography were measured at baseline and during the annual visit. RCRP and corneal HOAs were compared between the two groups after one-year treatment. Multivariate linear regression analysis was performed to determine the association between AL elongation and RCRP parameters, corneal HOAs, and other variables between the groups. ResultsAfter one-year treatment, axial elongation was slower in group A than in group B, with a difference of 0.15 mm. Children in group A showed smaller treatment zone size, smaller 3/4X value (describing the distance from the apex RCRP profile rising to its three-quarter-peak level), greater RCRP sum value within the pupillary area, and higher increases in corneal total HOAs and horizontal coma (Z31). AL elongation was significantly correlated with baseline age, baseline spherical equivalent refraction (SER), treatment zone size, and 3/4X value. ConclusionsOrtho-k lenses designed with smaller BOZD increased myopia control efficacy, induced a steeper distribution of the RCRP profile within the pupillary diameter, and induced greater increases in corneal total HOAs and horizontal coma (Z31). Lens-induced RCRP profile within pupillary diameter, rising to its three-quarter-peak level at a smaller distance, may show a better myopia control effect.

Lens nucleus dislocation in hypermature cataract: Case report and literature review

Introduction:Hypermature cataract is a form of late-stage cataract progression that can lead to a variety of complications. Spontaneous capsular rupture with lens nucleus displacement in hypermature cataracts has rarely been reported. We describe 2 cases of spontaneous dislocation of the lens nucleus in a hypermature cataract and perform a review of the literature on this complication.Patient Concerns:We report 2 rural men aged 50 and 76 years with deteriorating vision.Diagnosis:The final diagnosis was senile hypermature cataract with dislocation of the lens nucleus in both patients and secondary glaucoma for the second patient.Interventions and Outcomes:During admission, both patients complained of deteriorating vision. Slit-lamp examination showed lens nucleus dislocation into the anterior chamber. The 50-year-old patient exhibited a residual lens capsule and a turbid cortex, with a normal anterior chamber and intraocular pressure. The 76-year-old patient presented a shrunken and ruptured capsule and no cortex in the pupillary area, mild inflammation in the anterior chamber, and high intraocular pressure. Both patients underwent intracapsular cataract extraction combined with anterior vitrectomy and achieved good postoperative recovery.Conclusion:Lens nucleus dislocation in hypermature cataracts can be seen in clinical practice, particularly in underdeveloped areas. Early recognition and surgery can improve vision.

The Effects of High Energy Capsulotomy on Aqueous Cytokine Profiles and Pupil Size During Femtosecond Laser-Assisted Cataract Surgery.

To assess whether aqueous cytokine profiles and pupil size are altered when high capsulotomy energy is used in eyes undergoing femtosecond laser-assisted cataract surgery (FLACS), and if preoperative use of a topical non-steroidal anti-inflammatory drug (NSAID) has an effect on this. This prospective study recruited 83 eyes (63 patients) that were allocated to four treatment groups: conventional phacoemulsification (n = 20 eyes); FLACS with 90% capsulotomy energy without NSAID pretreatment (n = 20 eyes); FLACS with 90% capsulotomy energy with NSAID pre-treatment (n = 21 eyes); and FLACS with 150% capsulotomy energy with NSAID pretreatment (n = 22 eyes). Aqueous humor was collected before and after phacoemulsification to assess cytokine profiles. Pupil size was measured before and after laser capsulotomy. FLACS increased aqueous concentrations of pros-taglandin E2 (PGE2), interferon γ (IFN-γ), and interleukin 6 (IL-6) compared to conventional phacoemulsification. However, when increasing capsulotomy energy from 90% to 150% (with topical NSAID pretreatment), there was no significant increase in aqueous concentrations of PGE2 (37.7 ± 21.7 vs 33.6 ± 27.6 pg/mL, P = .99), IFN-γ (3.6 ± 1.1 vs 3.6 ± 0.8 pg/mL, P = .99), or IL-6 (7.1 ± 2.9 vs 6.3 ± 2.4 pg/mL, P = .99). For 90% and 150% capsulotomy energy, there was significant miosis following laser capsulotomy. Increased PGE2 concentration was significantly correlated with a reduction in pupil area (r = -0.58, P < .001) and pupil diameter (r = -0.57, P < .001). However, when a topical NSAID was given preoperatively, there was no difference in the degree of miosis between the 90% and 150% capsulotomy energy groups. Pretreatment with a topical NSAID prevented a rise in PGE2, IFN-γ, and IL-6 levels and excessive miosis when a higher capsulotomy energy was used. When a topical NSAID is used preoperatively, it is safe to use higher capsulotomy energy settings (with a low pulse energy femtosecond laser system) to achieve a satisfactory capsulotomy. [J Refract Surg. 2022;38(9):587-594.].

Deep learning for predicting refractive error from multiple photorefraction images

BackgroundRefractive error detection is a significant factor in preventing the development of myopia. To improve the efficiency and accuracy of refractive error detection, a refractive error detection network (REDNet) is proposed that combines the advantages of a convolutional neural network (CNN) and a recurrent neural network (RNN). It not only extracts the features of each image, but also fully utilizes the sequential relationship between images. In this article, we develop a system to predict the spherical power, cylindrical power, and spherical equivalent in multiple eccentric photorefraction images.ApproachFirst, images of the pupil area are extracted from multiple eccentric photorefraction images; then, the features of each pupil image are extracted using the REDNet convolution layers. Finally, the features are fused by the recurrent layers in REDNet to predict the spherical power, cylindrical power, and spherical equivalent.ResultsThe results show that the mean absolute error (MAE) values of the spherical power, cylindrical power, and spherical equivalent can reach 0.1740 D (diopters), 0.0702 D, and 0.1835 D, respectively.SignificanceThis method demonstrates a much higher accuracy than those of current state-of-the-art deep-learning methods. Moreover, it is effective and practical.