Validating the use of a stereoscopic robotized teleophthalmic drone slit lamp.

OBJECTIVE: To validate the use of a mechanized remotely operated stereoscopic drone slit lamp (DSL) in assessing anterior segment pathology in ophthalmology patients compared with conventional slit lamp (CSL). METHODS: Patients were recruited from eye clinics at Hotel Dieu Hospital in Kingston, Ontario, Canada. Each patient was assessed by 2 examiners. Examiners consisted of ophthalmology residents and staff attendings. Each examiner assessed the anterior chamber (AC) depth, presence or absence of cells, and/or presence of flare of the patient first using the DSL, followed by CSL. Qualitative data were collected on the ability to assess corneal integrity, infiltrates, foreign bodies, epithelial defects, and conjunctival injection using the DSL. RESULTS: 48 eyes of 42 participants were examined using the DSL and CSL. No significant within-examiner differences in AC depth or cell were detected. There was substantial agreement between the DSL and CSL when assessing AC cell and flare (κ = 72.6 and κ = 60.4, respectively) and moderate agreement when assessing AC depth (κ = 42.5). The DSL compared with CSL had a sensitivity and specificity of 98.3% (95% confidence interval [CI] 94-100) and 100% (95% CI 98.7-100), respectively, for detecting AC cell. The DSL had sensitivity and specificity of 100% (95% CI 97.5-100) and 88.2% (95% CI 80.2-96.1), respectively, for detecting AC flare. CONCLUSIONS: There was substantial agreement between the DSL and CSL when assessing AC depth, cell, and flare. Sensitivity and specificity for assessing these findings ranged from 88.2% to 100%. This DSL provides excellent capability for examination of anterior segment pathology in live patients, performing similarly to a CSL.

Electroretinogram Recording for Infants and Children under Anesthesia to Achieve Optimal Dark Adaptation and International Standards.

Electroretinogram (ERG) is the only clinical objective test available to assess retinal function. Full-field ERG (ffERG) measures the panretinal rod and cone photoreceptor function as well as inner retinal function and is an important measure in the diagnosis and management of inherited retinal diseases as well as inflammatory, toxic, and nutritional retinopathies. Adhering to international standards and maintaining retinal dark adaptation are critical to acquire valid and reliable dark-adapted (scotopic) and light-adapted (photopic) ffERG responses. Performing ffERG in infants and children is challenging and often requires general anesthesia in the operating room. However, maintaining retinal dark adaptation in the operating room is becoming increasingly difficult given the numerous light sources from anesthesiology monitoring systems and other equipment. A practical and widely applicable method for ffERG testing is described in the operating room that optimizes retinal dark adaptation. The method reduces operating room time by dark-adapting the patient before general anesthesiology is instituted. The operating room is modified for dark adaptation and any remaining light source in the darkened operating room is minimized with the use of a modified portable foldable darkroom that encloses the patient's head and the ERG examiner during ffERG scotopic recordings. The simple method adheres to ffERG international standards and provides valid reliable scotopic and photopic ffERG recordings that are critical to assess objective retinal function in this young age group where subjective assessment of visual function such as visual acuity and visual fields are not possible. Furthermore, the ffERG is the gold standard clinical test in detecting early onset inherited retinal diseases including Leber congenital amaurosis where approved gene therapy has become available. In sedated conditions, very low amplitude ffERG signals can be detected due to minimal orbicularis muscle activity interference, which is particularly relevant in patients after gene therapy to detect improved amplitude responses.

Automated instrument designed to determine visual photosensitivity thresholds.

The Ocular Photosensitivity Analyzer (OPA), a new automated instrument to quantify the visual photosensitivity thresholds (VPT) in healthy and light sensitive subjects, is described. The OPA generates light stimuli of varying intensities utilizing unequal ascending and descending steps to yield the VPT. The performance of the OPA was evaluated in healthy subjects, as well as light sensitive subjects with achromatopsia or traumatic brain injury (TBI). VPT in healthy, achromatopsia, and TBI subjects were 3.2 ± 0.6 log lux, 0.5 ± 0.5 log lux, and 0.4 ± 0.6 log lux, respectively. Light sensitive subjects manifested significantly lower VPT compared to healthy subjects. Longitudinal analysis revealed that the OPA reliably measured VPT in healthy subjects.

System for on- and off-axis volumetric OCT imaging and ray tracing aberrometry of the crystalline lens.

We present a new in vitro instrument for measuring shape and wavefront aberrations of the primate crystalline lens, both on- and off-axis, while simulating accommodation with a motorized lens stretching system. The instrument merges spectral domain optical coherence tomography (SD-OCT) imaging and ray tracing aberrometry using an approach that senses wavefront aberrations of the lens with the OCT probing beam. Accuracy and repeatability of aberration measurements were quantified. Preliminary experiments on two human and four cynomolgus monkey lenses demonstrate the ability of the system to measure the lens shape, spherical aberration and peripheral defocus, and their changes during simulated accommodation.

Robotic Remote Controlled Stereo Slit Lamp.

PURPOSE: Our purpose was to develop a robotic remotely operated stereo slit lamp system allowing three-dimensional stereo viewing and recording of the patient's examination via local area network, Internet, and satellite. METHODS: A commercial slit lamp was modified to accept motors and servos to permit control of all optical and mechanical components of the device. The custom graphical user interface with dual high-resolution real-time stereoscopic imaging, control/position indicators, overview video, and audio were transmitted via local area network, Internet, and satellite. Under University of Miami Institutional Review Board authorization, Internet connectivity enabled multiple examiners to simultaneously view and control the slit lamp and to collaboratively discuss diagnosis and treatment options. The remote clinicians used a tablet, laptop, or desktop computer to view and control the slit lamp. RESULTS: The network, Internet, satellite-connected system was controllable from the United States, Europe, and Canada while acquiring high-resolution, real-time video in all subjects. Control of the slit lamp through Ethernet, WiFi, and 4G exhibited total system latencies of 464 ± 58, 483 ± 64, and 870 ± 66 milliseconds when transmitting within the continent, and Ethernet control exhibited a latency of 606 ± 130 milliseconds when transmitting between continents. High- and low-magnification images of healthy volunteers were acquired by a remote clinician. CONCLUSIONS: The robotic remotely operated stereo slit lamp system allows three-dimensional stereo viewing and recording of the patient's examination via local area network, Internet, and satellite. TRANSLATIONAL RELEVANCE: The robotic remotely controlled stereo slit lamp system enables remote examination of human subjects.

A new, specular reflection-based, precorneal tear film stability measurement technique in a rabbit model: viscoelastic increases tear film stability.

PURPOSE: To develop a safe, noninvasive, noncontact, continuous in vivo method to measure the dehydration rate of the precorneal tear film and to compare the effectiveness of a viscoelastic agent in maintaining the precorneal tear film to that of a balanced salt solution. METHODS: Software was designed to analyze the corneal reflection produced by the operating microscope's coaxial illumination. The software characterized the shape of the reflection, which became distorted as the precorneal tear film evaporated; characterization was accomplished by fitting an ellipse to the reflection and measuring its projected surface area. Balanced salt solution Plus (BSS+) and a 2% hydroxypropylmethylcellulose viscoelastic were used as the test agents. The tear film evaporation rate was characterized and compared over a period of 20 minutes in 20 eyes from 10 New Zealand white rabbits. RESULTS: The ellipse axes ratio and surface area were found to decrease initially after each application of either viscoelastic or BSS+ and then to increase linearly as the tear film began to evaporate (P < 0.001) for eyes treated with BSS+ only. Eyes treated with BSS+ required 7.5 ± 2.7 applications to maintain sufficient corneal hydration during the 20-minute test period, whereas eyes treated with viscoelastic required 1.4 ± 0.5 applications. The rates of evaporation differed significantly (P < 0.043) between viscoelastic and BSS+. CONCLUSIONS: The shape and surface area of the corneal reflection are strongly correlated with the state of the tear film. Rabbits' corneas treated with viscoelastic remained hydrated significantly longer than corneas treated with BSS+.

Differential flow rate of commercially available triamcinolone with and without preservative through small-gauge needles.

OBJECTIVE: To compare the flow rate through different gauge needles of triamcinolone acetonide with benzyl alcohol (TABA) versus preservative-free triamcinolone acetonide injectable suspension (TAIS). MATERIALS AND METHODS: Experimental injections of 1 mL of TABA or TAIS were performed through a 27-, 30-, or 32-gauge needle. A piezoelectric pressure transducer connected to a personal computer was placed between the syringe and needle to record the force-time relationship and assess the flow rate (mL/s). Measurements were performed in triplicate. RESULTS: Flow rates were similar between preparations using a 27-gauge needle. Using a 30-gauge needle, the flow rate was 0.058 mL/s for TABA and 0.178 mL/s for TAIS. Using a 32-gauge needle, no flow was sustained by TABA, whereas the flow rate of TAIS was 0.114 mL/s (P < .05). CONCLUSION: TAIS can be injected through a 32-gauge needle without the risk of obstruction. Occlusions were seen with TABA using the 30- and 32-gauge needles.

A portable, contact animal fundus imaging system based on Rol's GRIN lenses.

OBJECTIVE: To demonstrate a cost-effective, portable, and simple-to-use fundus imaging system for laboratory animals. ANIMALS STUDIED: Albino rats, pigmented mice, albino guinea pigs, and New Zealand white rabbits. PROCEDURE: A contact fundus imaging system was designed and constructed using standard optical and mechanical components: a digital camera, an otoscope, a fiber optic light source, and standard optical lenses and mounts. Digital fundus video and photography of two albino rats, two pigmented mice, two New Zealand white rabbits, and two albino guinea pigs were obtained. For all animals examined, pupils were dilated and local anesthetic was administered. RESULTS: Digital images of the fundus were obtained in all animals. Contrast of retinal vasculature and overall image quality varied from one species to another, as the axial length, ocular optics, and retinal reflectance varied significantly across species. Light intensity and focus were optimized via the light source and lens focusing mount to produce high-quality images for each animal. CONCLUSIONS: The portable, cost-effective contact fundus imaging system was easy to use for fundus examination of laboratory animals.