Rehabilitation of orbital exenteration postsquamous cell carcinoma of orbit using magnet retained two-part silicone and acrylic prosthesis: A case report

ABSTRACT

Orbital exenteration performed to treat various neoplasms or nonmalignant diseases results in functional, aesthetic, and psychological issues for the patients. If reconstructive surgery is not possible or not desired by the patient, an orbital prosthesis is an excellent choice for cosmetic and psychological rehabilitation. An orbital prosthesis is aesthetic, durable, long lasting, cost-effective, and most importantly retentive. The present case report describes the rehabilitation of an orbital exenteration postsquamous cell carcinoma using a two-part prosthesis, in which retention is achieved by a combination of relining of anatomic undercuts and magnets.

Evaluation of macular visibility through a high-order aspheric intraocular lens using a simulated model eye

We evaluated the macular visibility of a newly designed extended depth of focus (EDOF) intraocular lenses (IOL) using a wide viewing system for macular manipulation (Risight;60D, Carl Zeiss Meditec AG) in a model eye and compared it with various other types of IOLs. We used a model eye that was constructed based on the Glustrand model to compare a newly designed EDOF IOL (DIB00V; Johnson & Johnson Surgical Vision), an EDOF IOL with a diffraction grating (ZXR00V; Johnson & Johnson surgical Vision), and a monofocal aspheric (DCB00V; Johnson & Johnson Vision, XY-1; HOYA Surgical Optics, Tokyo, Japan) or spherical IOL (NX70s; Santen Pharmaceutical Co., Ltd). In the model eye, a 1951 United States Air Force (USAF) test was placed at the location of the macula. The contrasts in a range of spatial frequencies were quantified using the images obtained from the 1951 USAF test target. The contrast at each spatial frequency was plotted and integrated to calculate the area under the curve contrast (AUC-contrast). Qualitative evaluations showed that good-quality images were obtained for all IOLs. At a spatial frequency of 16 LP/mm, the average contrast was the highest for the DIB00V and NX70s (0.216 each). The highest average contrast at 32 LP/mm was obtained using the NX70s (0.128), and at 64 LP/mm using the DIB00V (0.123). The horizontal AUC-contrast was the highest for the NX70s (8.754), and the vertical AUC-contrast was the highest for the DIB00V (8.334). On average, the DIB00V had the highest AUC-contrast value (8.227). The high-order aspheric IOL, DIB00V, was found to exhibit good macular visibility despite being an EDOF IOL.

Effect of intracorneal ring segments on posterior corneal topography in eyes with keratoconus

PURPOSE

To analyze the changes in the anterior and posterior corneal surfaces measured with a Scheimpflug imaging device in keratoconus patients implanted with intracorneal ring segments (ICRS) and to correlate those changes with the visual outcomes.

METHODS

This prospective interventional case series study included 92 eyes of 60 patients with keratoconus who underwent Kerarings (Mediphacos, Belo Horizonte, Brazil) ICRS implantation. Keratometric (K) readings, corneal asphericity (Q value) and elevations of both anterior and posterior corneal surfaces were evaluated using a Scheimpflug imaging device preoperatively and at 1, 3, 6 and 12 months after surgery.

RESULTS

The mean best corrected visual acuity (BCVA) improved from 0.61 to 0.19 logMAR at 12 months after surgery. Both anterior and posterior corneal surfaces showed significant flattening with statistically significant reduction of the mean anterior K reading by 3.39 D and the mean posterior K reading by 0.39 D (p<0.001) at 12 months. Statistically significant change of the anterior Q to a less negative value (from -1.05 to -0.36) was observed (p<0.001) with no significant change of the posterior Q value. Improvement of the anterior Q was significantly correlated to better postoperative BCVA (p=0.03). Better postoperative BCVA significantly correlated to better preoperative BCVA, flatter preoperative anterior and posterior K, less prolate anterior Q value and lower anterior elevations.

CONCLUSIONS

ICRS implantation has a significant flattening effect on both anterior and posterior corneal surfaces. Improvement of corneal asphericity is correlated to better visual outcome. Certain preoperative parameters were predictive factors of the postoperative visual improvement.

The effects of hydroxyapatite implantation with the autogenous sclera cap: A cohort study

We performed a novel hydroxyapatite (HA) prosthesis implantation method in which an HA implant was implanted into the scleral shell with an autogenous scleral cap. Twenty-six patients who had undergone the novel HA prosthesis implantation method and 32 patients who had undergone traditional HA prosthesis implantation were retrospectively reviewed. The postoperative activity of the artificial eye was measured by the Hirschberg test combined with arc perimetry. The visual analog score (VAS) was used to evaluate 2-month postoperative pain and 2-month postoperative discomfort. HA implant vascularization was measured with enhanced magnetic resonance imaging (MRI) 2 and 6 months after the operation. The enhancement volume (VE) and the volume of the HA implant (VHA) were measured. All cases were followed up for 2 years. Measurement data were processed using SAS 6.12. There was a statistically significant difference (P = .016) between the percentages of excellent grade in the two groups. Two months after implantation, the median pain scores of the study and control groups were 2 and 2.5, respectively, and there was a statistically significant difference (W = 585.0, P = .004); there was a statistically significant difference (W = 535.5, P = .000) between the median discomfort scores of the study group (score = 1) and control group (score = 2); the mean VE/VHA values of the study and control groups were 0.3075 and 0.1535, respectively, and there was a statistically significant difference (t = -8.196, P = .000). Six months after implantation, the VE/VHA values of the study and control groups were 0.9686 and 0.5934, respectively, and there was a statistically significant difference (W = 549.0, P = .000). Within 2 years of postoperative follow-up, there were no serious complications in the study group. In the study group, in which the hydroxyapatite implant was implanted into a preserved scleral shell with unaltered muscles and covered with an autogenous scleral cap, postoperative activity and the fibrovascularization of the HA implant were significantly increased, and postoperative pain and discomfort were significantly reduced.

Modified Treatment Of Shallow Fornix For Better Retention Of Ocular Prosthesis

BACKGROUND

The purpose of this study is to share the experience of a modified surgical technique for treating shallow inferior fornix to enhance the retention of cosmetic ocular prosthesis in a tertiary care hospital. It was a Quasi experimental study, carried out at Khalid Eye Hospital, Karachi, Pakistan from January to December 2018.

METHODS

This study included twenty-five patients between the ages of 20-40 years belonging to either gender having an anophthalmic socket with shallow inferior fornices unable to retain cosmetic ocular prosthesis. Three pieces of Silicone tube were placed deep within the inferior fornix with the help of 2-0 Vicryl suture, taking bite of the inferior orbital rim periosteum. Main outcome measure was deepening of the inferior fornix with better retention of the ocular prosthesis. All the patients were followed up for a period of one year after the surgery. Study dynamics were briefed to all the patients and study approval obtained from the hospital ethical review committee.

RESULTS

This study included a total of twenty-five patients of both genders. Mean age was 29.6±6.53 years. By the end of the follow up period, twenty-four (96%) out of the twenty-five patients were satisfied with a proper retention of ocular prosthesis within the fornix along with complete lid closure. One (4%) patient required revision surgery because of extrusion of the silicone tube piece after one month. Mean follow up period was 358.5±16.76 days.

CONCLUSION

This modified technique does not require expensive consumables and proved to be effective in terms of cosmetic and functional outcome.

Understanding the Experiences of Living With an Artificial Eye in Children With Retinoblastoma-Perspectives of Children and Their Parents

Background: Retinoblastoma is a rare form of pediatric eye cancer for which enucleation is a common treatment modality. There is an increasing focus upon the impact of enucleation on children and families. This study aimed to explore the experiences of children and their families following enucleation to consider the barriers that may be encountered when adjusting to living with an artificial eye and identifying the support services and strategies used to address these barriers. Methods: Using a descriptive qualitative approach, interviews were conducted with 12 parents and seven children and thematic analysis was used to identify four themes representing the perspective of parents and children. Results: Parent themes identified were (a) entry into the world of retinoblastoma; (b) the importance of specialist support; (c) a family learning to cope; and (d) navigating school. The perspectives of children were (a) the importance of preparation and play; (b) positive reinforcement and hospital support; (c) support and openness at home; and (d) the importance of good school planning. Two overarching themes related to parent and child adaptation were also identified. Discussion: The study findings reveal that the process of adapting to living with an artificial eye extended to influencing decisions around parenting, learning to advocate for their child, and supporting children through school and peer relationships. For children, the importance of ongoing support and information was vital to enhance understanding, adaptation, and development of independence. Overall, the study suggests that children and families undergoing enucleation need continuing, individualized, and specialist support.

A bio-inspired polarization navigation sensor based on artificial compound eyes

Insect compound eyes are optical systems with small volume and a compact structure. The ommatidia in the dorsal rim area of some insects have polarized vision, which can perceive the polarization pattern of the sky and provide them with navigation information. In this paper, inspired by the polarization-sensitive compound eyes of insects, a bio-inspired polarization navigation sensor based on artificial compound eyes is designed. The sensor consists of an artificial compound eye, an integrated polarization detector and an integrated circuit. The optical path of the sensor uses the lens defocus method, which can ensure that the sensor obtains redundant polarization information. The integrated polarization detector is used to obtain the polarization information of the incident light, and the integrated circuit is responsible for the calculation. To extract effective information from images, we propose a multi-threshold segmentation method to filter and classify effective pixels. We use the least squares method to fit the inherent error of the sensor and then compensate it. The indoor calibration accuracy of the sensor is ±0.3°, and the outdoor calibration accuracy is ±0.5°. The sensor can provide accurate direction information for general smart mobile devices. The size of the sensor is 4 × 4 × 2 cm, and the weight is only 15 g. The key components of the sensor can be mass-produced, and it is a miniaturized and low-cost polarization navigation sensor.

The Management of Congenital Microphthalmia With Orbital Cyst: A Case Series

PURPOSE

To describe a series of patients treated for congenital microphthalmia associated with orbital cyst and recommend a management protocol.

METHODS

This retrospective case series comprised 6 patients (7 eyes) who attended an oculoplastic tertiary medical center from 2001 to 2018. Clinical, treatment, and outcome data were collected from the electronic files. Main outcome measures were preservation of vision and cosmetic appearance.

RESULTS

Four patients were diagnosed at birth. Six cysts were located inferiorly and one superiorly. Two patients had a visual potential of light perception or better in the affected eye. In 4 eyes, the cyst was initially retained and the eye was fitted with a custom-made conformer. In 1 eye, the fornices were too shallow for a conformer, warranting fornix reconstruction and cyst excision. Early surgery was required in 1 eye for an expanded cyst and large orbit volume, and in another eye the cyst had overgrown the orbit, causing bone erosion and remodeling. Cosmetic results were good in 3 of the eyes in which the cyst was retained in early childhood, stimulating orbital growth.

CONCLUSIONS

Congenital microphthalmia with orbital cyst is rare. Management should focus on preserving visual potential, especially in unilateral cyst cases when the other eye is also microphthalmic. Otherwise cosmetic symmetry is the main concern; cyst retention combined with ocular conformers may stimulate socket expansion. The authors found that, in most cases, if treated early, enucleation was avoidable during cyst excision. Early assessment, meticulous follow-up, and individually tailored treatment are warranted. [J Pediatr Ophthalmol Strabismus. 2022;59(3):192-199.].

Small head movements increase and colour noise in data from five video-based P-CR eye trackers

We empirically investigate the role of small, almost imperceptible balance and breathing movements of the head on the level and colour of noise in data from five commercial video-based P-CR eye trackers. By comparing noise from recordings with completely static artificial eyes to noise from recordings where the artificial eyes are worn by humans, we show that very small head movements increase levels and colouring of the noise in data recorded from all five eye trackers in this study. This increase of noise levels is seen not only in the gaze signal, but also in the P and CR signals of the eye trackers that provide these camera image features. The P and CR signals of the SMI eye trackers correlate strongly during small head movements, but less so or not at all when the head is completely still, indicating that head movements are registered by the P and CR images in the eye camera. By recording with artificial eyes, we can also show that the pupil size artefact has no major role in increasing and colouring noise. Our findings add to and replicate the observation by Niehorster et al., (2021) that lowpass filters in video-based P-CR eye trackers colour the data. Irrespective of source, filters or head movements, coloured noise can be confused for oculomotor drift. We also find that usage of the default head restriction in the EyeLink 1000+, the EyeLink II and the HiSpeed240 result in noisier data compared to less head restriction. Researchers investigating data quality in eye trackers should consider not using the Gen 2 artificial eye from SR Research / EyeLink. Data recorded with this artificial eye are much noisier than data recorded with other artificial eyes, on average 2.2-14.5 times worse for the five eye trackers.

Modified procedure of anterior orbital exenteration enables eye socket reconstruction: A retrospective cohort study

The conventional procedure of anterior orbital exenteration is unfavorable for eye socket reconstruction, whereas a modified procedure enables socket reconstruction and prosthesis fitting. Our study aims to compare the cosmetic outcomes between these 2 surgical techniques.We retrospectively recruited patients treated with modified or conventional exenteration during January 2015 to May 2021 in our hospital. The conventional approach was performed along with dermis-fat graft transplantation. The modified approach was conducted followed by eye socket reconstruction and eyelid blepharoplasty. The clinical data were collected and analyzed, including demographics, tumor characteristics, postoperative complications, tumor-related events, and cosmetic outcomes.Forty-nine patients were consecutively recruited in this study, including 22 cases of modified exenteration and 27 cases of conventional exenteration. Forty-four subjects (89.8%) were diagnosed with ocular surface malignancies (conjunctival melanoma and squamous cell carcinoma) and 5 subjects (10.2%) were diagnosed with extraocular stage of uveal melanoma. After follow-up for 31.8 ± 17.1 months, the 1-, 2-, 5-year overall survival rate was calculated as 100%, 79.2%, and 59.2% in the Modified group, and 94.2%, 73.8%, and 51.5% in the Conventional group. Comparison of the survival curves showed no significant differences. In the Modified group, all patients received orbital implant placement and eye socket reconstruction. The implant motility was satisfactory in 12 cases (54.5%) with movements in 3 to 4 directions. The eyelid function was acceptable in 17 cases (77.3%) with no entropion, ectropion or lower lid laxity. Ocular prosthesis was delivered in 17 cases (77.3%) with successful fitting in 11 cases (64.7%). The self-rated cosmetic score was statistically (t test, P < .0001) higher in the Modified group (6.7 ± 0.9) than the Conventional group (2.2 ± 0.4).The modified approach to anterior orbital exenteration enables eye socket reconstruction and cosmetic rehabilitation while still preserves the curable chance for the treatment of advanced periocular/intraocular malignancies.

Effective discrimination of gas-phase peptide conformers using TIMS-ECD-ToF MS/MS

In the present work, four, well-studied, model peptides (e.g., substance P, bradykinin, angiotensin I and AT-Hook 3) were used to correlate structural information provided by ion mobility and ECD/CID fragmentation in a TIMS-q-EMS-ToF MS/MS platform, incorporporating an electromagnetostatic cell (EMS). The structural heterogeneity of the model peptides was observed by (i) multi-component ion mobility profiles (high ion mobility resolving power, R ∼115-145), and (ii) fast online characteristic ECD fragmentation patterns per ion mobility band (∼0.2 min). Particularly, it was demonstrated that all investigated species were probably conformers, involving cis/trans-isomerizations at X-Pro peptide bond, following the same protonation schemes, in good agreement with previous ion mobility and single point mutation experiments. The comparison between ion mobility selected ECD spectra and traditional FT-ICR ECD MS/MS spectra showed comparable ECD fragmentation efficiencies but differences in the ratio of radical (˙)/prime (') fragment species (H˙ transfer), which were associated with the differences in detection time after the electron capture event. The analysis of model peptides using online TIMS-q-EMSToF MS/MS provided complementary structural information on the intramolecular interactions that stabilize the different gas-phase conformations to those obtained by ion mobility or ECD alone.

Refractive corneal inlay implantation outcomes: a preliminary systematic review

PURPOSE

To review all case series of refractive corneal inlay implantation: Flexivue (Presbia, Netherlands), Invue (BioVision, Brügg, Switzerland) and Icolens (Neoptics, Hünenberg, Switzerland) performed in presbyopia patients and to evaluate the reported visual outcomes. In addition, our aim is to provide assessment for complications and to report the satisfaction rates.

METHODS

PubMed, Web of Science and Scopus databases were consulted using "refractive corneal inlay", "Flexivue Inlay", "Invue Inlay" and "Icolens inlay" as keywords. 147 articles were found, and they were assessed considering the inclusion and exclusion criteria. After filtering, this systemic review included ten articles, published between 2011 and 2020.

RESULTS

308 eyes from 308 participants were enrolled in this systematic review. Mean maximum follow-up was 13.9 months. Nine of the ten case series included used femtosecond laser for the corneal pocket creation. Mean pocket depth was 293.75 µm. 77.5% of the eyes reported a postoperative uncorrected near visual acuity of 20/32 or better, and 19.20% of the inlay-implanted eyes achieved an uncorrected distance visual acuity of 20/20 or better. The most prominent complications were halos, pain, photophobia, and poor distance visual acuity. 27 eyes (8.7%) had to be explanted due to complications, such as near-distance spectacle dependence or blurred distance vision.

CONCLUSION

Refractive corneal inlay outcomes demonstrated high efficacy, safety, and satisfaction rates. Furthermore, it is a reversible technique. However, the findings must be viewed with caution due potential conflict of interest. Further research with higher sample size is needed to validate these findings.

Evaluation of Different Polymerization Methods of Ocular Prosthesis Acrylic Resins on Subcutaneous Tissue Inflammatory Response in Rats

Objectives

This study aimed to evaluate the influence of different polymerisation methods of acrylic resin for ocular prostheses on the subcutaneous tissue inflammatory response of rats.

Methods

The study was conducted at the Basic Sciences Department, Araçatuba Dental School, São Paulo State University (UNESP), Brazil, from 2016 to 2018. The samples were prepared by water bath (WB), microwave energy (MW) or autopolymerisation (AP) (n = 20 samples per group). The inflammatory response (cell count and immunohistochemical analysis of interleukin [IL]-1β, IL-6, tumour necrosis factor [TNF]-α, IL-17 and macrophage inflammatory protein-3α) was analysed by the implantation of a sample from each group in the subcutaneous tissue of 20 Wistar rats and evaluated after seven, 15, 30 and 60 days. The quantitative and qualitative data were analysed using analysis of variance and Tukey tests (P <0.05) and visual comparison, respectively.

Results

There was a moderate inflammatory infiltrate for the MW and AP groups and a light infiltrate for the WB group after seven days. The inflammatory infiltrate and the immunolabeling of tested targets decreased gradually during the 60-day period. The AP group had the highest immunolabeling of TNF-α (seven days), IL-1β and IL-17 (at 15 and 30 days) and IL-6 (at 30 and 60 days). The WB and MW groups showed greater immunolabeling at 15 and 30 days, while the MW group also had high results at 60 days.

Conclusion

Polymerisation by microwave energy and by chemical activation resulted in a higher inflammatory response.

Assessment of optogenetically-driven strategies for prosthetic restoration of cortical vision in large-scale neural simulation of V1

The neural encoding of visual features in primary visual cortex (V1) is well understood, with strong correlates to low-level perception, making V1 a strong candidate for vision restoration through neuroprosthetics. However, the functional relevance of neural dynamics evoked through external stimulation directly imposed at the cortical level is poorly understood. Furthermore, protocols for designing cortical stimulation patterns that would induce a naturalistic perception of the encoded stimuli have not yet been established. Here, we demonstrate a proof of concept by solving these issues through a computational model, combining (1) a large-scale spiking neural network model of cat V1 and (2) a virtual prosthetic system transcoding the visual input into tailored light-stimulation patterns which drive in situ the optogenetically modified cortical tissue. Using such virtual experiments, we design a protocol for translating simple Fourier contrasted stimuli (gratings) into activation patterns of the optogenetic matrix stimulator. We then quantify the relationship between spatial configuration of the imposed light pattern and the induced cortical activity. Our simulations in the absence of visual drive (simulated blindness) show that optogenetic stimulation with a spatial resolution as low as 100 [Formula: see text]m, and light intensity as weak as [Formula: see text] photons/s/cm[Formula: see text] is sufficient to evoke activity patterns in V1 close to those evoked by normal vision.

Refractive prediction of four different intraocular lens calculation formulas compared between new swept source optical coherence tomography and partial coherence interferometry

Purpose

To compare the biometry and prediction of postoperative refractive outcomes of four different formulae (Haigis, SRK/T, Holladay1, Barrett Universal II) obtained by swept-source optical coherence tomography (SS-OCT) biometers and partial coherence interferometry (PCI; IOLMaster ver 5.4).

Methods

We compared the biometric values of SS-OCT (ANTERION, Heidelberg Engineering Inc., Heidelberg, Germany) and PCI (IOLMaster, Carl Zeiss Meditec, Jena, Germany). Predictive errors calculated using four different formulae (Haigis, SRKT, Holladay1, Barrett Universal II) were compared at 1 month after cataract surgery.

Results

The mean preoperative axial length (AL) showed no statistically significant difference between SS-OCT and PCI (SS-OCT: 23.78 ± 0.12 mm and PCI: 23.77 ± 0.12 mm). The mean anterior chamber depth (ACD) was 3.30 ± 0.04 mm for SS-OCT and 3.23 ± 0.04 mm for PCI, which was significantly different between the two techniques. The mean corneal curvature also differed significantly between the two techniques. The difference in mean arithmetic prediction error was significant in the Haigis, SRKT, and Holladay1 formulae. The difference in mean absolute prediction error was significant in all four formulae.

Conclusions

SS-OCT and PCI demonstrated good agreement on biometric measurements; however, there were significant differences in some biometric values. These differences in some ocular biometrics can cause a difference in refractive error after cataract surgery. New type SS-OCT was not superior to the IOL power prediction calculated by PCI.

Spectacle Cord-retained Oculo-Orbital Prosthesis

Retention of an orbital prosthesis plays a key role in treatment success and patient acceptance as does aesthetics. Though numerous retentive aids are available such as implants, adhesives, etc, the cost, surgical aspect, difficulty of use and allergic potential may compromise efficiency. This report describes the case of an 11-year post-enucleation poor retinoblastoma patient, in whom an unfavourable defect leads to a major prosthetic challenge (from point of view of retention and camouflage). This report describes a simple, economical, and user-friendly approach to obtain satisfactory retention and camouflage for such patients with spectacle cords and customised spectacles. Key Words: Oculo-orbital prosthesis, Spectacle, Cord.

[Justification for the use of modular intraocular lens (experimental study)]

The rising number of cases requiring intraocular lens (IOL) exchange, including those for refractive reasons, drives the search for methods to minimize the trauma of the procedure. Lens implants with modular optics may lower complication risks.

PURPOSE

To test the use of modular IOL on a laboratory animal in an experiment.

MATERIAL AND METHODS

A novel modular IOL was implanted into rabbit eyes in disjointed form with subsequent intraocular assembling. Presence of long-term side effects of implantation and possibility of atraumatic optical disk exchange were evaluated 4 months after the surgery.

RESULTS

A total of 3 rabbit eyes underwent IOL implantation surgery, no technical difficulties were encountered. Postoperatively two eyes were quiet with proper central IOL position and no deformations in the haptic and optical parts. Epithelial cell proliferations did not hinder intraocular disassembly/assembly of the modular IOL. Optical disk spontaneously dislocated into anterior chamber in one eye, with subsequent chronic inflammation and corneal edema. In the late postoperative period, no difficulties were observed in disconnecting the optical part from the haptic ring and their coupling. Optical disk exchange did not require extensive handling of the haptic, except that of fixation leaflets during release/capture of the optics. Mechanical impact of the procedure on the lens capsule and Zinn's zonule fibers was minimal.

CONCLUSION

The experiment has validated the functionality and feasibility of the modular IOL principle designed to lower the threshold for decisions on IOL exchange in postoperative correction of clinical refraction. In most cases, rabbit eyes were demonstrated to exhibit long-term stable fixation, relative ease and safety of optical disk exchange eliminating the need for traumatic capsular bag manipulations.

Custom-made artificial eyes using 3D printing for dogs: A preliminary study

Various incurable eye diseases in companion animals often result in phthisis bulbi and eye removal surgery. Currently, the evisceration method using silicone balls is useful in animals; however, it is not available to those with impaired cornea or severe ocular atrophy. Moreover, ocular implant and prostheses are not widely used because of the diversity in animal size and eye shape, and high manufacturing cost. Here, we produced low-cost and customized artificial eyes, including implant and prosthesis, using computer-aided design and three-dimensional (3D) printing technique. For 3D modeling, the size of the artificial eyes was optimized using B-mode ultrasonography. The design was exported to STL files, and then printed using polycaprolactone (PCL) for prosthesis and mixture of PCL and hydroxyapatite (HA) for ocular implant. The 3D printed artificial eyes could be produced in less than one and half hour. The prosthesis was painted using oil colors and biocompatible resin. Two types of eye removal surgery, including evisceration and enucleation, were performed using two beagle dogs, as a preliminary study. After the surgery, the dogs were clinically evaluated for 6 months and then histopathological evaluation of the implant was done. Ocular implant was biocompatible and host tissue ingrowth was induced after in vivo application. The custom-made prosthesis was cosmetically excellent. Although long-term clinical follow-up might be required, the use of 3D printed-customized artificial eyes may be beneficial for animals that need personalized artificial eye surgery.

Small eye movements cannot be reliably measured by video-based P-CR eye-trackers

For evaluating whether an eye-tracker is suitable for measuring microsaccades, Poletti & Rucci (2016) propose that a measure called 'resolution' could be better than the more established root-mean-square of the sample-to-sample distances (RMS-S2S). Many open questions exist around the resolution measure, however. Resolution needs to be calculated using data from an artificial eye that can be turned in very small steps. Furthermore, resolution has an unclear and uninvestigated relationship to the RMS-S2S and STD (standard deviation) measures of precision (Holmqvist & Andersson, 2017, p. 159-190), and there is another metric by the same name (Clarke, Ditterich, Drüen, Schönfeld, and Steineke 2002), which instead quantifies the errors of amplitude measurements. In this paper, we present a mechanism, the Stepperbox, for rotating artificial eyes in arbitrary angles from 1' (arcmin) and upward. We then use the Stepperbox to find the minimum reliably detectable rotations in 11 video-based eye-trackers (VOGs) and the Dual Purkinje Imaging (DPI) tracker. We find that resolution correlates significantly with RMS-S2S and, to a lesser extent, with STD. In addition, we find that although most eye-trackers can detect some small rotations of an artificial eye, the rotations of amplitudes up to 2∘ are frequently erroneously measured by video-based eye-trackers. We show evidence that the corneal reflection (CR) feature of these eye-trackers is a major cause of erroneous measurements of small rotations of artificial eyes. Our data strengthen the existing body of evidence that video-based eye-trackers produce errors that may require that we reconsider some results from research on reading, microsaccades, and vergence, where the amplitude of small eye movements have been measured with past or current video-based eye-trackers. In contrast, the DPI reports correct rotation amplitudes down to 1'.

An Innovative Method for Iris Positioning in a Prosthetic Eye

AIM

An apparatus named "laser pointer apparatus" is proposed for accurate iris positioning in a prosthetic eye.

BACKGROUND

Loss of an eye leads to significant psychological stress due to functional disability and societal response to the facial disablement. Custom-made eye prosthesis is a good option to rehabilitate such defects. Inaccurately positioned iris in a prosthetic eye results in squint eye appearance leading to poor esthetics and poor psychological impact among such unfortunate patients.

TECHNIQUE

A new apparatus called a laser pointer apparatus, which is an assembly of an occlusal plane analyzer, web camera, laser pointer, and software, has been introduced for iris positioning in a prosthetic eye.

CONCLUSION

Iris positioning is one of the key steps in fabricating an eye prosthesis. Laser pointer apparatus is a reliable method for iris positioning in a prosthetic eye.

CLINICAL SIGNIFICANCE

Positioning the iris to the ideal symmetrical position is a cardinal step in the fabrication of an ocular prosthesis. This article aims to introduce a "laser pointer apparatus" to orient iris in a prosthetic eye objectively to overcome the subjective errors.

Investigation of the impact of blur under mobile attentional orientation using a vision simulator

It is well-known that correction of blur can improve visual perception. However, it is unclear how the beneficial effect of correction is affected by the regions of correction and the spatial uncertainty introduced by the retinal stimulation. The purpose of this study was two-fold: first, to compare the impacts of blur correction between isoeccentric locations of the visual field; and second, to evaluate the effect of spatial cueing in each corrected location on performing a simple task. Five subjects were asked to complete a simple detection task of a small dark spot stimulus presented randomly at four cardinal retinal locations (eccentricity: 5°) under manipulation of attention via an exogenous cue. Both clear and blurred targets were randomly displayed across the visual field and viewed monocularly through a vision simulator, used to minimize peripheral ocular aberrations. Results confirmed the advantage of clear vs/ blurred images under spatial uncertainty. It was also found that the visual benefit from blur correction is unequal at isoeccentric locations, even for a simple detection task. While manipulation of attention in the presence of spatial uncertainty significantly modulated response time (RT) performance, no differential effect was observed for clear and blurred stimuli, suggesting that attention has only a small effect on the optical benefit for a simple detection task when the display is depleted (no distractor). Those observations highlight the importance of field performance asymmetries in optical interventions and may offer useful implications for the design of extrafoveal refractive correction. Further studies are needed to elucidate how the focus of attention interacts with the perceived gain of vision correction.