Ophthalmic Instruments Research Articles

Glutathione Modulates Hydrogen Sulfide Release and the Ocular Hypotensive Action of Diallyl Polysulfide Compounds.

Hydrogen sulfide (H2S) is an endogenous transmitter with the potential to regulate aqueous humor dynamics and protect retinal neurons from degeneration. The aim of the present study was two-fold: (a) to evaluate the release of H2S from two polysulfides, diallyl disulfide (DADS), and diallyl trisulfide (DATS); and (b) to investigate their ocular hypotensive actions in normotensive male and female rabbits in the presence and absence of GSH. H2S was quantified hourly for up to 6 h using a H2S-Biosensor (World Precision Instruments, Sarasota, Fl). Intraocular pressure (IOP) was assessed in normotensive New Zealand Albino rabbits using a pneumotonometer (model 30 classic; Reichert Ophthalmic Instruments, Depew, NY, USA). In the presence of GSH, there was an increase in the in vitro release of H2S produced by DADS and DATS. Both DADS and DATS also caused a dose-dependent reduction in IOP in male and female rabbits, in both treated and untreated eyes. For instance, in male animals, the presence of GSH (3% and 5%) significantly (p < 0.05, n = 5) enhanced the ocular hypotensive action of DADS (2%) and DATS (2%) from 14.02 ± 2.89% to 18.67 ± 5.6% and from 16.22 ± 3.48 to 23.62 ± 5.79%, respectively. GSH enhanced both H2S release and ocular hypotensive action of the polysulfides in a manner that was dependent on the number of sulfur atoms present in each polysulfide. Furthermore, female animals were less sensitive to the IOP-lowering action of the polysulfides, when compared to their male counterparts.

Modifying the Silt Lamp by Using a White Laser in Place of the Halogen Light

This paper explores the modification of the slit lamp, a vital ophthalmic instrument, by replacing the traditional halogen light source with a white laser. This modification aims to enhance the diagnostic capabilities and efficiency of the slit lamp. White laser technology offers superior brightness, intensity, and color accuracy, which improves the visibility and differentiation of ocular tissues. Additionally, white lasers are more energy-efficient, provide consistent light output, and require less maintenance. The redesign process includes adjustments to the optical system, incorporating specialized filters and lenses, and ensuring proper thermal management. The integration of a high-resolution digital camera system with white laser illumination further improves image quality and diagnostic precision. The study outlines the benefits, potential challenges, and implementation steps, concluding that the use of white lasers in slit lamps can significantly enhance the effectiveness of ocular diagnostics, benefiting both ophthalmologists and patients.

Short-Cycle Autoclave Sterilization of Instruments in Same-Day Ophthalmic Surgeries

What Is the Issue? The volume of ophthalmic surgeries is increasingly high, with cataract surgery being 1 of the most performed surgeries in Canada. Infections following ophthalmic surgeries, while rare, can cause severe complications that may lead to irreversible vision loss. Reducing postsurgery infections is a high priority in clinical practice. Running a full wrapped, terminal steam sterilization cycle for ophthalmic instruments in autoclaves may be inefficient for ophthalmic surgeries and may cause unnecessary heavy economic and environmental burdens due to high surgical volumes. Using instruments sterilized on a short cycle between sequential same-day ophthalmic surgeries may help improve efficiency and reduce resources used. These instruments are generally processed using autoclaves (i.e., steam sterilizers); the effectiveness of a shorter-cycle method of sterilization is unclear. What Did We Do? To inform decisions regarding the use of autoclaves for short-cycle sterilization for sequential same-day instrument use in ophthalmic surgery, we sought to identify and summarize evidence comparing this method to full-cycle sterilization of wrapped instruments and identify any relevant recommendations. We searched key resources, including journal citation databases, and conducted a focused internet search for relevant evidence published since 2012. One reviewer screened articles for inclusion based on predefined criteria. What Did We Find? In a laboratory setting to simulate sequential same-day procedures, short-cycle sterilization with interrupted dry time for unwrapped ophthalmic instruments is feasibly as effective as full-cycle sterilization for wrapped instruments using the STATIM autoclave. Similarly, short-cycle sterilization with interrupted dry time for contained ophthalmic instruments is feasibly as effective as full-cycle sterilization for contained instruments using the AMSCO autoclave. For sequential same-day ophthalmic procedures, wet instruments sterilized by a short-cycle process with an interrupted dry time can remain sterile for at least 3 minutes if kept in a covered sterilizer containment device. One guideline recommends that wrapped or unwrapped ophthalmic instruments sterilized by a short-cycle process without full drying should be stored in a covered containment device until retrieved by staff wearing sterile gloves and gowns in the operating room for the subsequent surgery after a short delay. Phaco handpieces should be immediately primed with a balanced salt solution and remain wet as they sit on the sterile instrument table. We did not identify any clinical setting evidence from studies or autoclave manufacturers. It is unclear if clinical outcomes differ between patients undergoing sequential same-day ophthalmic surgeries using short-cycle sterilized instruments and those undergoing surgery using full-cycle sterilized instruments. What Does This Mean? Preliminary laboratory evidence and guideline recommendations supporting the use of autoclaves for short-cycle sterilization of instruments for sequential same-day ophthalmic surgeries are available. However, there is no clinical effectiveness evidence available on this process in patient settings. Future research is necessary to understand the clinical safety of using instruments sterilized by short cycles for sequential same-day use for patients undergoing ophthalmic surgeries. In addition to the evidence and recommendations identified, other factors, such as environmental influence, may be useful considerations when making decisions about short-cycle sterilization for sequential same-day instrument use for ophthalmic surgery.

Value for money of reusable versus disposable ophthalmic instruments for intravitreal injections

aim: The aim of this study was to follow the instruments’ pathways and cost each segment to calculate whether reusable or disposable ophthalmic instruments offer better value for money for intravitreal injections. methods: The cycles and costs of reusable and single-use disposable instruments used for intravitreal injections were mapped out, including purchase costs, transport to and from the place of use, opening and disposal, sterilisation, replacement, salary costs of staff involved, etc. results: The cost of using reusable instruments for intravitreal injections (NZ$29.00) was lower than the cost of using disposable instruments ($30.51) by $1.51 per patient. conclusions: Intravitreal injections performed with reusable instruments offer better value for money than when performed with disposable instruments. This equates to a beneficial financial saving just for this one low-complexity case. Such savings can multiply significantly when considering the instruments used in a wider variety of ophthalmic procedures. There are of course trade-offs between safety, quality, cost and sustainability.

Reusing surgical materials for cataract surgery: an assessment of potential contamination.

To evaluate microbiological cultures of cataract surgical devices and products that were reused for multiple cases. Aravind Eye Hospital, Pondicherry, Tamil Nadu, India. Prospective cohort study. Samples from multiple surgical instruments and products that were reused for consecutive cataract surgeries underwent bacterial and fungal cultures and were monitored alongside positive controls for 7 days. This included instruments that were processed using immediate use steam sterilization (IUSS) between cases (eg, surgical cannulas, syringes, phacoemulsification and coaxial/bimanual irrigation/aspiration [I/A] tips, phacoemulsification and I/A sleeves) (Group 1), instruments that were used without sterilization between cases (eg, phacoemulsification tubing/handpieces, coaxial I/A handpieces) (Group 2), and the residual (unused) fluid from balanced salt solution bags after being used for multiple patients (Group 3). 3333 discrete samples were collected from all 3 product groups that were reused across multiple patients. In all collected samples, no bacterial or fungal growth was observed. Of the 3241 cataract surgeries that used reused and IUSS-sterilized instruments alongside instrument sets cultured on the same day and balanced salt solution bags shared across multiple patients, no eyes developed endophthalmitis over a 6-week follow-up period. Bacterial or fungal growth was not found in extensive microbiological cultures of IUSS-sterilized ophthalmic surgical instruments and cataract surgical products that were reused in multiple patients. This microbiological data complements clinical endophthalmitis data from 2 million consecutive cases at the Aravind Eye Hospital, suggesting that their instrument and surgical supply processing practices may allow for safe and sustainable ophthalmic care.

Efficacy of common decontamination techniques used in eye care facilities in Ghana

PurposeTo evaluate the efficacy of common methods used in the decontamination of non-critical and semi-critical ophthalmic equipment in Ghana. DesignThis study was conducted in two phases. First, a descriptive cross-sectional study was carried out, followed by a microbiological study MethodsQuestionnaires were distributed online to eye care practitioners. The common decontamination procedures identified from the online questionnaires were used in decontaminating the surfaces of the ophthalmic instruments. Swabs were taken from the instruments both before and immediately after decontamination (within the first 30s), as well as at 10-minute intervals up to 40 minutes after decontamination. The swabs were cultured on nutrient agar for 24 hours at 37 °C, and the contamination levels were estimated. ResultsThe most commonly used disinfection technique in the selected eye clinics in Ghana was the use of Methylated spirit (34 %), and the least, Iso-alcohol swabs (1 %). All the decontamination methods were efficacious in the reduction of contamination levels on the surfaces of ophthalmic instruments. Hand sanitiser, Parazone (sodium hypochlorite), Autoclave, and UV showed highly effective decontamination activity compared to Methylated spirit, Hydrogen peroxide, and Isopropyl alcohol. There was a significant reduction in contamination for each of the time points (p < 0.001), except for 40 minutes after decontamination (p = 0.063ns), when compared to the contamination level before decontamination. ConclusionIn Ghana, commonly used decontamination methods are effective in reducing levels of contamination of ophthalmic instruments, with their recontamination rates comparable to the use of autoclaves and UV germicidal irradiation.

Evaluation of the standard test methods for optical coherence tomograph for the posterior segment of the human eye

Optical Coherence Tomography (OCT) has revolutionized retinal imaging by offering non-invasive high-resolution three-dimensional visualization capabilities. OCT has become the standard of care in routine ophthalmological practice, especially for the posterior segment. Given its widespread clinical applications, establishing standardized test devices and methods for key OCT parameters is imperative to ensure both optimal imaging performance and diagnostic accuracy and treatment effectiveness. As a widely applied standard, ISO 16971:2015 published by the International Organization for Standardization specifies the minimum requirements, test device, and methods for OCT for the posterior segment of the human eye. Notably, these standards lacked experimental validation. In the present study, we implement the test device according to ISO 16971:2015, and assess a commercially available ophthalmic OCT instrument with the suggested test device and methods. Results show that the test device and methods could facilitate a rudimentary evaluation of OCT key parameters. Nevertheless, refinements of the test device and methods are requisite to enhance measurement accuracy, reliability, traceability, and practicability, catering to the diverse needs of manufacturers, end-users, and regulatory entities.

Satisfaction with Teleophthalmology Services: Insights from Remote Areas of Taiwan.

During and after the COVID-19 pandemic, teleophthalmology provided access to eye care for rural populations. This study aimed to assess the efficacy of and satisfaction with an integrated real-time videoconferencing module. This project incorporated ophthalmic instruments and telecommunication devices and provided on-site consultations via videoconferencing. Both patients and healthcare providers completed satisfaction questionnaires. From May 2020 to May 2021, this project provided eye care services to 395 patients (aged 6-90 years). The most frequent eye condition was chronic conjunctivitis (n = 197), followed by senile cataract (n = 163), dry eye (n = 103), and refractive error (n = 95). Among them, 40 (10.1%) patients were referred to secondary or tertiary hospitals for further evaluation or treatment. In total, 181 recruited respondents provided good satisfaction scores in all dimensions, including quality of medical care (4.50 of 5.00), financial aspects of care (4.48), supportive attitude toward the project (4.47), quality of service (4.40), and quality of telecommunication (4.40). Women had a substantially more supportive attitude toward the project, and 25 healthcare providers provided low ratings in areas representing the quality of telecommunication (4.04) and user-friendliness of the instrument (4.00). This teleophthalmology system provided efficient and satisfactory eye care to participants in remote communities. However, better internet access and training in instrument use can reduce obstacles to the future implementation of the project.

Digital Challenges: Investigating Computer Vision Syndrome in Thai Esports Through a Case-Control Approach.

To determine the factors associated with eyestrain in esports athletes in Bangkok compared with controls. A cross-sectional descriptive study was conducted between April and June 2023, involving 160 male participants (aged 20-35 years) who used digital devices, consisting of esports athletes and a control group. Data were collected using a general information questionnaire, Computer Vision Syndrome Questionnaire (CVS-Q), and Depression anxiety stress scale-21 (DASS-21). Ophthalmic instruments were used for the eye examinations by an optometrist. Seventy-six esports athletes showed significantly lower visual performance than controls in logMAR visual acuity (p < 0.020), phoria (p < 0.001), negative fusional vergence (blur, break, and recovery) (p < 0.012, p < 0.004 and p < 0.039), positive fusional vergence (blur, break, and recovery) (p < 0.005, p < 0.001 and p < 0.005), monocular estimation method (p < 0.001), monocular and binocular accommodative facility (p < 0.001), and vergence facility (p < 0.001). A study on risk factors for CVS found that esports athletes were significantly more likely to have CVS (p < 0.001). Work environments with high-intensity lighting significantly increase the risk of CVS compared to low-intensity lighting (p < 0.001). The use of a digital device for >4 h/day, having a history of alcohol consumption, and stress significantly increased the risk of CVS (p < 0.001, p < 0.023, p < 0.048). This study found that esports athletes experienced vision health problems, indicating the need to prevent eyestrain caused by the use of digital devices.

A Novel Electromagnetic Driving System for 5-DOF Manipulation in Intraocular Microsurgery.

This work presents a novel electromagnetic driving system that consists of eight optimized electromagnets arranged in an optimal configuration and employs a control framework based on an active disturbance rejection controller (ADRC) and virtual boundary. The optimal system configuration enhances the system's compatibility with other ophthalmic surgical instruments, while also improving its capacity to generate magnetic force in the vertical direction. Besides, the optimal electromagnet parameters provide a superior comprehensive performance on magnetic field generation capacity and thermal power. Hence, the presented design achieves a stronger capacity for sustained work. Furthermore, the ADRC controller effectively monitors and further compensates the total disturbance as well as gravity to enhance the system's robustness. Meanwhile, the implementation of virtual boundaries substantially enhances interactive security via collision avoidance. The magnetic and thermal performance tests have been performed on the electromagnet to verify the design optimization. The proposed electromagnet can generate a superior magnetic field of 2.071 mT at a distance of 65 mm with an applied current of 1 A. Moreover, it demonstrates minimal temperature elevation from room temperature (25 °C) to 46 °C through natural heat dissipation in 3 h, thereby effectively supporting prolonged magnetic manipulation of intraocular microsurgery. Furthermore, trajectory tracking experiments with disturbances have been performed in a liquid environment similar to the practical ophthalmic surgery scenarios, to verify the robustness and security of the presented control framework. The maximum root mean square (RMS) error of performance tests in different operation modes remains 35.8 μm, providing stable support for intraocular microsurgery.

Ramón Castroviejo (1904–1987): The father of the modern corneal transplantation

Ramón Castroviejo Briones was born in 1904 in Logroño, Spain. He received his medical education at the University of Madrid, where he graduated in 1927. In 1929, he received a fellowship to work as assistant in the Ear, Nose, and Throat Hospital and College of Chicago. In 1930, he passed his American Board Examination and returned to Europe to visit the centers where keratoplasty was a fact. He visited the University eye clinics of Madrid, Paris, Vienna, Berlin, and Prague. When he returned to the United States, Castroviejo had a clear idea of what was being done in Europe and what he hoped to achieve. William L. Benedict had offered him a research fellowship at the Mayo Clinic, in Rochester, Minnesota, which Castroviejo accepted. In 1932, Dr. Maynard C. Wheeler granted Castroviejo a Research Fellowship at the new Eye Institute of the College of Physicians and Surgeons of Columbia University. He moved to New York, where he continued his research in animals in the Eye Institute of the Columbia Presbyterian Medical Center, and was an early developer of techniques for transplanting corneal tissue from the eyes of those who had just died to damaged eyes of the living. While not being the first to successfully graft human cornea, he improved the technique of the operation in the 1930s and 1940s, prompting the worldwide adoption of corneal transplantation as a standard way to deal with severe corneal pathology. His keratoplasty technique, creating a rectangular rather than circular “window” in the cornea, was the secret to his successful transplants, and remained standard until more efficient suture materials became available. The surgeon described this technique in 1937 to the American College of Surgeons. He contended that rectangular windows gave better results than the circular ones that had been tried earlier, since their edges could be fitted better to merge with and become a living part of the rest of the eye. Although the medical community was slow to recognize his successes, Castroviejo was eventually lauded for his sight‐saving corneal tissue transplant techniques, which he continued to refine and teach for many years. Castroviejo also promoted the donation of corneal tissue in the United States and designed numerous ophthalmic instruments, including the Castroviejo needle holder ‐an instrument used in eye, dental and other forms of microsurgery‐ Castroviejo callipers and corneal scissors. He became the director of Ophthalmology at St. Vincent's Hospital before he opened his own hospital when he bought the Hammond House in New York. After closing his private hospital he retired as clinical professor of the University of New York and moved permanently to Madrid, where he founded the Instituto Castroviejo, at the Complutense University of Madrid, and organized the Spanish Eye Bank, maintaining extensive clinical activity whenever his health permitted. Ramón Castroviejo died in 1987, at the age of 82, and is widely recognized as one of the 10 most influential people in ophthalmology of the 20th century.

Regional Institute of Ophthalmology and Government Ophthalmic Hospital: The Heart of Heritage

Regional Institute of Ophthalmology and Government Ophthalmic Hospital: The Heart of Heritage

20/20: Where are Orthoptists Going?

ABSTRACT The year 2020 has been greatly anticipated by the entire ophthalmic community. This year’s Scobee lecture will be a photographic look at our past with the orthoptists and pediatric ophthalmologists we have learned from, taught, and worked with. A sobering snapshot of our present will reveal a world with extreme medical access inequality. This creates a need for an inexpensive screening device for amblyogenic anisometropia. A technique for such a fast and inexpensive screening device will be shown using first retinoscopy; and then compare the effectiveness of the direct Heine streak ophthalmoscope, a common ophthalmic instrument, will be shown to be effective in screening for ≥1 diopter of spherical anisometropia. The challenges of the present hint at an optimistic future for orthoptists, expanding their role as physician extenders to help ease the medical access inequalities in the world. Finally, I introduce the patron saint of the blind and those with vision impairment.

Introduction to Ophthalmic Surgery Course 2022-23 An Overview

I attended the course in September 2022. The course was beneficial for me as it allowed me to gain hands-on experience using the microscope, working with ophthalmic instruments, and familiarising myself with common ophthalmological surgical techniques. The course has in the past contributed 1 point towards the ST1 Ophthalmology portfolio – the latest version of the Ophthalmology ST1 evidence folder states 1 point will be awarded for ‘Evidence of other ophthalmology simulation training’. The course also incorporates spending time on the EyeSi surgical simulator. Having the opportunity to use the EyeSi is beneficial for trainees as they need to complete the available modules throughout their training, whilst those doctors/students wanting to apply for Ophthalmology training, completing 4 hours on the simulator also contributes 1 point towards the portfolio.

GAED Medal Lecture 2022: Challenging the Dogma in Diabetic Neuropathy and Beyond

AbstractDogma, according to the Britannica Dictionary, is ”a belief or set of beliefs that is accepted by the members of a group without being questioned or doubted.” Thus, in 2001, the heretical idea that corneal confocal microscopy (CCM)—an ophthalmic instrument—could be used to assess neurological disease truly challenged the dogma. The repurposing of CCM to study diabetic neuropathy and other neurodegenerative diseases is a wonderful illustration of being in the right time and place and having honest and open conversations between very different medical disciplines to 'challenge the dogma.' The Gulf Association of Diabetes and Endocrinology (GAED) Medal Lecture in 2022 and the European Association for the Study of Diabetes (EASD) Camillo Golgi Prize in 2019 have enabled me to tell my personal story in relation to the past, present, and future of CCM as a clinical tool to diagnose and predict neurodegeneration and identify nerve regeneration in clinical trials of new therapies for peripheral and central neurodegenerative diseases.

Vision-Based Eye Image Classification for Ophthalmic Measurement Systems

The accuracy and the overall performances of ophthalmic instrumentation, where specific analysis of eye images is involved, can be negatively influenced by invalid or incorrect frames acquired during everyday measurements of unaware or non-collaborative human patients and non-technical operators. Therefore, in this paper, we investigate and compare the adoption of several vision-based classification algorithms belonging to different fields, i.e., Machine Learning, Deep Learning, and Expert Systems, in order to improve the performance of an ophthalmic instrument designed for the Pupillary Light Reflex measurement. To test the implemented solutions, we collected and publicly released PopEYE as one of the first datasets consisting of 15 k eye images belonging to 22 different subjects acquired through the aforementioned specialized ophthalmic device. Finally, we discuss the experimental results in terms of classification accuracy of the eye status, as well as computational load analysis, since the proposed solution is designed to be implemented in embedded boards, which have limited hardware resources in computational power and memory size.

Evaluation of the corneal biomechanical properties and corneal thickness in patients with Graves' orbitopathy.

To evaluate the corneal biomechanical properties and central corneal thickness in patients with Graves' orbitopathy (GO). A total of 132 eyes of 66 patients with GO and 108 eyes of 54 healthy subjects were enrolled. Eyes with GO were classified as high score clinical activity score (CAS, ≥ 3) (Group 1, n = 64) and low CAS score (< 3) (Group 2, n = 68). Corneal biomechanical parameters [corneal hysteresis (CH), corneal resistance factor (CRF)], Goldmann-correlated intraocular pressure (IOPg), and corneal-compensated IOP (IOPcc) levels were measured with Ocular Response Analyzer (ORA, Reichert Ophthalmic Instruments, Buffalo, NY) and compared between the groups. The mean CH values were found as 9.6 ± 1mmHg in Group 1, 10.2 ± 0.9mmHg in Group 2, and 11.4 ± 1.7mmHg in the Control Group (p < 0.001). In post hoc analysis the mean CH was significantly lower in Group 1 than Group 2 and Control Group (Group 1-Group 2, p < 0.001; Group 1-Control Group, p < 0.001). The mean CRF was found as 10.5 ± 2.1 in Group 1, 10.4 ± 2.2 in Group 2, and 10.43 ± 2.0 in the Control group. There was no statistically significant difference between the groups in CRF measurements (p = 0.959). The mean IOPcc values were found as 17.1 ± 3.6mmHg in Group 1, 15.8 ± 4.0mmHg in Group 2 and 15.2 ± 4.1mmHg in the Control Group. The IOPcc and IOPg measurements between all groups were statistically significant (p = 0.009, p = 0.027, respectively). Corneal biomechanical measurements were different in the GO patients with varying CAS scores compared to healthy individuals.

COVID-19 and Nursing Care of Ophthalmic Patients During Pandemic

Background: The corona virus, a novel, enveloped single stranded RNA virus (sarscOv-2) which has mainly affected respiratory system with life threatening results. The SARS-CoV-2 has been detected in several body fluids including tear and discharge of patients suffering from conjunctivitis. The aim of this paper is to explore the nursing care of person with ophthalmic problems.&#x0D; Methods: A literature review was conducted using data based of Google scholar, Google, Pubmed, Medline since 2015-2023.&#x0D; Results: An ophthalmic nurse can play a key role in teaching a patient and their attendants about general eye care and protection of vision during COVID-19 monitoring the patient’s condition, as well as ophthalmic instruments after it’s use have been are two main responsibilities of the nurse working in the ophthalmic units. Nurses also have responsibilities to maintain the safe and clean working environment of the unit, making the environment clean and safe.&#x0D; Conclusion: The environment of the eye ward must be clean, safe and free from organism. A nurse should warn the patients not to touch or rub the eyes and dressings or eye shields with unprotected hand during this COVID-19 pandemic.&#x0D;

Correlation between biomechanical and endothelial corneal properties in myopic children

AbstractPurpose: The purpose of the study is to investigate the endothelial layer and biomechanical properties of the cornea, in a group of low‐moderate myopic children.Methods: This prospective study included only the right eye from myopic patients younger than 18. We performed a complete ophthalmologic examination, including autorefractometry under cycloplegia (to determine the spherical equivalent ‐ SE), slit lamp and fundus examination, visual acuity and ocular tonometry. Furthermore, the patients were examined with the Aladdin biometer (Topcon, Tokyo, Japan) to determine central corneal thickness (CCT) and axial length (AL), with the Specular Microscope (Nidek, Gamagori, Japan) to determine number (Num) and density (CD) of endothelial cells, and with the Ocular Response Analyser (Reichert Ophthalmic Instruments Inc., Depew, NY) to determine corneal hysteresis (CH) and resistance factor (CRF). IBM SPSS Statistics 26 was used for statistical analysis.Results: Our study included 64 right eyes from 64 patients (51.56% male, 48.44% female). The average age was 14.27 years (standard deviation 2.71). The average SE is −2.57 (SD 1.62), AL 24.69 (SD 1.15), CCT 0.565 (SD 0.036), CH 12.32 (SD 1.88), CRF 12.64 (SD 2.24), Num cell 175.17 (SD 38.55), CD 3126.86 (SD 192.74). There are significant correlations between the biomechanical properties of the cornea and the characteristics of the endothelial layer. We found a statistically significant moderate positive correlation between CH and CD in this paediatric myopic population (Pearson's r of 0.353, p 0.004), and also between CRF and CD (Pearson's r of 0.2557, p 0.041). Between AL and the number of cells, there is a significant negative correlation (Pearson's r of −0.287, p 0.025). There are no significant correlations between the number of endothelial cells and CH, CRF, SE or CCT, or between CD and AL, CCT, SE.Conclusions: Our study reveals that in children with myopia, the endothelial cell count is higher in corneas with a higher hysteresis and resistance factor. Moreover, the relationship between the axial length and the number of endothelial cells suggests an impact of myopia on the endothelial layer and warrants further studies, including a larger number of patients and more corneal properties, such as corneal diameter and curvature.

Widespread subclinical cellular changes revealed across a neural-epithelial-vascular complex in choroideremia using adaptive optics

Choroideremia is an X-linked, blinding retinal degeneration with progressive loss of photoreceptors, retinal pigment epithelial (RPE) cells, and choriocapillaris. To study the extent to which these layers are disrupted in affected males and female carriers, we performed multimodal adaptive optics imaging to better visualize the in vivo pathogenesis of choroideremia in the living human eye. We demonstrate the presence of subclinical, widespread enlarged RPE cells present in all subjects imaged. In the fovea, the last area to be affected in choroideremia, we found greater disruption to the RPE than to either the photoreceptor or choriocapillaris layers. The unexpected finding of patches of photoreceptors that were fluorescently-labeled, but structurally and functionally normal, suggests that the RPE blood barrier function may be altered in choroideremia. Finally, we introduce a strategy for detecting enlarged cells using conventional ophthalmic imaging instrumentation. These findings establish that there is subclinical polymegathism of RPE cells in choroideremia.