Quantification of gaze reaction time in infants with Pediatric Perimeter.

PURPOSE: We quantified the eye/head (gaze) reaction time in infants to establish a normative database for the Pediatric Perimeter device. Additionally, we tested the hypothesis that gaze reaction time will reduce with age. METHODS: A cross-sectional study was conducted. Healthy infants between 3 to 10 months of age were recruited. Peripheral visual field stimuli (hemifield and quadrant stimuli) were presented in the Pediatric Perimeter device. Infant's gaze to these stimuli was observed, documented in real time, and video recorded for offline analysis. RESULTS: A total of 121 infants were tested in three age group bins [3-5 months, n = 44; >5-7 months, n = 30 and >7-10 months, n = 47]. Overall, 3-5 months old had longer reaction time when compared to the older infants particularly for stimuli presented in the quadrants (Kruskal-Wallis, p<0.038). A significantly asymmetric difference (p = 0.025) in reaction time was observed between the upper (median = 820ms, IQR = 659-1093ms) and lower quadrants (median = 601ms, IQR = 540-1052ms) only for the 3-5 months old infants. CONCLUSION: This study provides the normative gaze reaction time of healthy infants. With increase in age, there is reduction in reaction time and disappearance of reaction time asymmetry in quadrant stimuli. The longer reaction time for upward gaze could be due to delayed maturation of neural mechanisms and/or decreased visual attention.

The magnitude of monocular light attenuation required to elicit the Pulfrich illusion.

In the Pulfrich illusion, the depth of a moving object is misperceived due to induced retinal disparity and/or interocular velocity differences arising from differences in luminance, contrast, or spatial frequency between the two eyes. These effects have been shown to occur both for visual deficits and for optical corrections that introduce significant binocular differences between the retinal images. However, it remains unknown to what extent the illusion might arise given normal variation between the eyes, such as natural interocular variation in pupil diameter (anisocoria). To assess this, we examined the threshold interocular retinal illuminance difference required to experience illusory depth in two random-dot fields moving in opposite directions in 24 normally-sighted observers with dilated pupils. Interocular difference in retinal illuminance was induced by placing neutral density filters of different intensities before the left eye. A minority of subjects (n = 8) did not provide meaningful data on changes in the experience of illusory depth with interocular difference in retinal illuminance and four subjects showed biases >±10% from the 50% point of subjective equality in the psychometric function. For the remaining 12 participants, the retinal illuminance had to differ by approximately 40% for the depth between the planes to become visible at threshold levels. This difference was approximately constant over a range of absolute luminance levels from 10 to 80 cd/m2. Our results suggest that while motion-in-depth illusions due to interocular differences in retinal illuminance may be pronounced in certain ophthalmic diseases or following certain optical interventions, it is unlikely to be manifest as a result of normal interocular variations in retinal illuminance. Further, our results also point towards the existence of substantial individual differences in the experience of what is otherwise thought of as a readily appreciable motion-in-depth illusion.

Use of a Tablet Attachment in Teleophthalmology for Real-Time Video Transmission from Rural Vision Centers in a Three-Tier Eye Care Network in India: eyeSmart Cyclops.

PURPOSE: This study describes the development of an attachment for a smart tablet to stream live video information of an eye examination through the slit lamp. METHODS: A tablet attachment was developed that enables the live streaming of video from the slit lamp from the rural vision centers of the LVPEI network. A video streaming solution like Skype Lite was used to transmit the same. The eyeSmart app was utilized for the documentation of the clinical information of the patients. RESULTS: A tablet attachment of eyeSmart Cyclops was developed and piloted in 3 vision centers of the LVPEI network. CONCLUSION: The use of real-time video transmission illustrates a novel teleophthalmology solution in low resource settings to screen rural populations. The ability to transmit live video enables gathering more information than static images.

Low-cost three-dimensional printed orbital template-assisted patient-specific implants for the correction of spherical orbital implant migration.

PURPOSE: To describe the outcomes of a patient-specific implant (PSI), fabricated using a three-dimensional (3D) printed orbital template and placed in the basin of the inferior orbital fissure to correct inferotemporally migrated spherical orbital implant. METHODS: This is a single-center, prospective, consecutive, interventional, case series of six patients, with non-porous, spherical, orbital implant migration that underwent implant recentration surgically with a novel technique. Migration was subclassified either as decentration that did not affect the prosthetic retention or as displacement that affected the prosthetic retention in the eye socket. Only implant displacements were treated. The primary outcome measure was centration of the implant clinically and radiologically, with ability to retain the prosthesis. RESULTS: At a mean follow-up of 21 months, all six orbital spherical implants remained centered. There were no cases of extrusion, exposure, or migration of either implants. There were no cases of PSI displacement. Additional procedures to optimize the aesthetic outcome of the customized ocular prosthesis (COP) required were simultaneous fornix formation suture in three patients, subsequent fornix formation with mucus membrane graft in two patients, and levator resection and sulcus hyaluronic acid gel injection in one patient each. The mean PSI implant weight was 2.66 ± 0.53 g. The mean COP weight was 2.2 ± 0.88 g postoperatively. The median patient satisfaction with the procedure was 9 on 10. CONCLUSION: A 3D printing-assisted PSI placed in the basin of the inferior orbital fissure allows recentration of the migrated implant over a follow-up of 21 months without complications.