TFOS Lifestyle: Impact of the digital environment on the ocular surface.

Eye strain when performing tasks reliant on a digital environment can cause discomfort, affecting productivity and quality of life. Digital eye strain (the preferred terminology) was defined as "the development or exacerbation of recurrent ocular symptoms and/or signs related specifically to digital device screen viewing". Digital eye strain prevalence of up to 97% has been reported, due to no previously agreed definition/diagnostic criteria and limitations of current questionnaires which fail to differentiate such symptoms from those arising from non-digital tasks. Objective signs such as blink rate or critical flicker frequency changes are not 'diagnostic' of digital eye strain nor validated as sensitive. The mechanisms attributed to ocular surface disease exacerbation are mainly reduced blink rate and completeness, partial/uncorrected refractive error and/or underlying binocular vision anomalies, together with the cognitive demand of the task and differences in position, size, brightness and glare compared to an equivalent non-digital task. In general, interventions are not well established; patients experiencing digital eye strain should be provided with a full refractive correction for the appropriate working distances. Improving blinking, optimizing the work environment and encouraging regular breaks may help. Based on current, best evidence, blue-light blocking interventions do not appear to be an effective management strategy. More and larger clinical trials are needed to assess artificial tear effectiveness for relieving digital eye strain, particularly comparing different constituents; a systematic review within the report identified use of secretagogues and warm compress/humidity goggles/ambient humidifiers as promising strategies, along with nutritional supplementation (such as omega-3 fatty acid supplementation and berry extracts).

FaceGuard: A Wearable System To Avoid Face Touching.

Most people touch their faces unconsciously, for instance to scratch an itch or to rest one's chin in their hands. To reduce the spread of the novel coronavirus (COVID-19), public health officials recommend against touching one's face, as the virus is transmitted through mucous membranes in the mouth, nose and eyes. Students, office workers, medical personnel and people on trains were found to touch their faces between 9 and 23 times per hour. This paper introduces FaceGuard, a system that utilizes deep learning to predict hand movements that result in touching the face, and provides sensory feedback to stop the user from touching the face. The system utilizes an inertial measurement unit (IMU) to obtain features that characterize hand movement involving face touching. Time-series data can be efficiently classified using 1D-Convolutional Neural Network (CNN) with minimal feature engineering; 1D-CNN filters automatically extract temporal features in IMU data. Thus, a 1D-CNN based prediction model is developed and trained with data from 4,800 trials recorded from 40 participants. Training data are collected for hand movements involving face touching during various everyday activities such as sitting, standing, or walking. Results showed that while the average time needed to touch the face is 1,200 ms, a prediction accuracy of more than 92% is achieved with less than 550 ms of IMU data. As for the sensory response, the paper presents a psychophysical experiment to compare the response time for three sensory feedback modalities, namely visual, auditory, and vibrotactile. Results demonstrate that the response time is significantly smaller for vibrotactile feedback (427.3 ms) compared to visual (561.70 ms) and auditory (520.97 ms). Furthermore, the success rate (to avoid face touching) is also statistically higher for vibrotactile and auditory feedback compared to visual feedback. These results demonstrate the feasibility of predicting a hand movement and providing timely sensory feedback within less than a second in order to avoid face touching.

Novel mechanism of decreased iris vasculature density after cosmetic iris implants.

A 25-year-old man presented with decreased vision in both eyes, approximately 4 years following bilateral bright ocular cosmetic iris implantation. On examination, he was found to have bilateral elevated intraocular pressures, anterior chamber cells and flare, chronic peripheral anterior synechiae and significantly reduced endothelial cell counts. Ultrasound biomicroscopy demonstrated compression of the peripheral iris, resulting in synechial angle closure in both eyes. Surgical removal of the implants was performed without additional complication. On removal, bilateral iris atrophy was evident with non-reacting pupils and permanent mydriasis. Optical coherence tomography angiography showed a reduction in iris vasculature density that is more pronounced in the area of the iris atrophic defects. This case suggests that cosmetic iris implants may compress iris vasculature, resulting in decreased iris perfusion resulting in atrophic mydriasis and iris defects. This is a potential novel mechanism for complications in eyes with cosmetic iris implants.

Ocular Discomfort and Quality of Life Among Patients in the Dry Eye Assessment and Management Study.

PURPOSE: To assess the association of severity of ocular discomfort with measures of quality of life among patients with moderate to severe dry eye disease (DED). METHODS: This is a prospective, observational, cohort study within a randomized clinical trial. Patients (N = 535) in the Dry Eye Assessment and Management study with moderate to severe DED completed the Ocular Surface Disease Index on DED symptoms, the SF-36 on quality of life, and the Brief Ocular Discomfort Inventory questionnaire and had a comprehensive ophthalmic assessment by a study-certified clinician. The ocular discomfort on average over the past week was scored on an 11-point scale (0 for no discomfort and 10 for discomfort as bad as you can imagine). RESULTS: The average ocular discomfort scores for patients ranged from 0 to 10, with a mean of 4.28. Discomfort scores did not vary with demographic characteristics, signs of DED, self-reported depression, or self-reported nonocular pain conditions. Ocular discomfort scores did correlate moderately to strongly with total Ocular Surface Disease Index scores (Spearman correlation coefficient, rs, 0.47-0.67) and with measures of interference with activities of daily living [general activity level, mood, walking ability, ability for normal work, relations with other people, sleep, and enjoyment of life (rs = 0.39-0.65)]. CONCLUSIONS: Among patients in the Dry Eye Assessment and Management study, worse ocular discomfort was associated with worse overall DED symptoms and interfered to a greater degree with activities of daily living. Ocular discomfort is an important part of the assessment of patients with DED.

Pterygium excision after LASIK.

PURPOSE: To describe the management of a symptomatic pterygium in an eye with previous LASIK surgery. OBSERVATIONS: Significant infiltration of the LASIK flap by the pterygium was noted intraoperatively necessitating the frequent use of a crescent blade. The infiltrative behavior of the pterygium may reflect the inflammatory state after laser refractive surgery. CONCLUSIONS AND IMPORTANCE: Pterygia are highly prevalent, and with the increasing prevalence of LASIK surgery, the coexistence of these 2 conditions is expected to be increasingly more likely. Optimizing the management of this condition can result in a good functional and cosmetic outcome.

Ocular pain response to treatment in dry eye patients.

PURPOSE: Pain is a frequently reported symptom in dry eye disease (DED). We examine the factors associated with ocular pain severity and patient-reported improvement in ocular pain to commonly used dry eye and pain treatments. METHODS: Cross-sectional study of patients presenting for dry eye management. Demographics, ocular and medical history, OSDI, numeric pain scale, pain descriptors, and subjective response to tried eye drop, systemic, and non-pharmacologic treatments were collected. Statistical analysis was performed to identify differential treatment response in patients with various pain levels using the non-parametric test for trend. RESULTS: 144 patients were categorized into 4 groups according to reported pain severity. Increasing pain was significantly associated with younger age, history of refractive surgery, higher OSDI score, and less likelihood of corneal staining. Patients with higher pain intensity were more likely to report a history of fibromyalgia, depression, anxiety, and migraine. Patients with greater pain severity were less responsive to treatment with artificial tears (p < 0.001), lubricating ointment (p = 0.002), steroid eye drops (p = 0.03), cyclosporine 0.05% (p = 0.03), 20% autologous serum tears (p = 0.01), hot compresses (p = 0.04), lid hygiene (p = 0.002) and punctal occlusion (p = 0.03). CONCLUSIONS: Dry eye patients with severe ocular pain often have associated psychological and systemic pain conditions. Treating the underlying DED is beneficial in reducing ocular pain, however the low rate of a satisfactory response highlights the need for further investigation of effective therapies. Cross-sectional studies can provide guidance in the treatment of patients with dry eye-related ocular pain and guide future prospective studies on potentially effective therapies.

Chronic Conjunctivitis From a Retained Contact Lens.

PURPOSE: To help clinicians diagnose and manage unilateral recalcitrant chronic bacterial conjunctivitis secondary to a retained soft contact lens and describe the first report of Gram-negative bacteria causing this condition. METHODS: Chart review of successive cases presenting with unilateral chronic conjunctivitis with positive cultures and a retained contact lens. RESULTS: Three cases were identified and described. Culturing of the retained contact lenses grew Pseudomonas aeruginosa in the first case, Achromobacter xylosoxidans in the second, and Staphylococcus epidermidis in the third. All three patients were successfully treated with removal of the retained lens and targeted antibiotic eyedrop therapy. CONCLUSIONS: Unilateral chronic recurrent or recalcitrant purulent papillary conjunctivitis is rare, and a retained contact lens should be suspected in patients with a history of wearing contact lenses. Careful examination with double eversion of the upper eyelid and sweeping of the fornices can recover the offending lens. Although only Gram-positive organisms have been isolated in previous reports, two of our three cultures grew Gram-negative organisms, highlighting the importance of broad-spectrum antibiotic usage for these cases.

Keratoprosthesis Decentration and Tilt Results in Degradation in Image Quality.

PURPOSE: To study the effect of decentration and tilt of the type I Boston keratoprosthesis (KPro) on image quality in both aphakic and pseudophakic eyes. METHODS: An optical ray-tracing program was used to simulate the image projected onto the retina in an eye with a perfectly centered KPro, and in eyes with varying degrees of KPro decentration and tilt. Decentration was modeled along a typical white-to-white distance of 12.0 mm, and the corresponding tilt was calculated assuming a radius of curvature of 8.0 mm, the radius of curvature of the backplate of the KPro. Both aphakic and pseudophakic eyes were simulated, and the corresponding modulation transfer function curves, point spread functions, and astigmatism were analyzed. RESULTS: The perfectly centered KPro produced a high-quality image with no induced astigmatism. Increasing decentration beyond approximately 0.5 mm resulted in poorer image quality with a more pronounced effect in the presence of an intraocular lens. Using models of the normal eye as a threshold, image degradation due to decentration becomes clinically significant at approximately 1.4 mm and 0.9 mm for the aphakic and pseudophakic cases, respectively. Astigmatism introduced by decentration is approximately 0.25 D cylinders at those thresholds. CONCLUSIONS: Decentration of up to 0.5 mm had no significant impact on image quality and an attempt at good intraoperative centration of the KPro within this range is important. Conversely, decentration of 0.9 mm or more during surgical implantation can result in significant degradation in retinal image quality including astigmatism. The effect is greater in the pseudophakic eye.

Accuracy of Visual Estimation of LASIK Flap Thickness.

PURPOSE: To assess the accuracy of surgeons' visual estimation of LASIK flap thickness when created by a femtosecond laser by comparing it to ultrasound measurements. METHODS: Surgeons were asked to visually estimate the thickness of a femtosecond flap during the procedure. Total corneal thickness was measured by ultrasound pachymetry prior to the procedure and the stromal bed was similarly measured after flap lifting. The estimates from three experienced surgeons (cornea fellowship trained and more than 5 years in practice) were compared to those of three cornea fellows, with each surgeon evaluating 20 eyes (120 total). Surgeons were not told the thickness of the flaps unless required for safety reasons. RESULTS: The average difference between visual and ultrasonic estimation of LASIK flap thickness was 15.20 µm. The flap was 10 µm thicker than estimated in 37% of eyes, 20 µm thicker in 17% of eyes, and 30 µm thicker in 10% of eyes. The largest deviation was 53 µm. There was no statistically significant difference between the accuracy of experienced surgeons and fellows (P = .51). CONCLUSIONS: There are significant differences between surgeons' visual estimates and ultrasonic measurements of LASIK flap thickness. Relying on these visual estimates may lead to deeper excimer laser ablation than intended. This could lead to thinner residual stromal beds and higher percent tissue altered than planned. The authors recommend that surgeons measure flaps intraoperatively to maximize accuracy and safety. [J Refract Surg. 2017;33(11):765-767.].

Measuring Forward Light Scatter by the Boston Keratoprosthesis in Various Configurations.

PURPOSE: Light scatter results in degradation of visual function. An optical bench model was used to identify the origins of scatter in the setting of a Boston keratoprosthesis (KPro). The effect of various modifications in the device design and light-blocking configurations was explored. METHODS: A KPro was mounted on a contact lens holder on a bench, and forward light scatter was recorded with a camera attached to a rotating goniometer arm. Scattered light was recorded at different angles for different KPro modifications, and the point-spread function (PSF) curves were recorded. The area under the curve (AUC) was calculated for each PSF curve. RESULTS: The isolated KPro optical cylinder in a totally blackened holding lens had a tight PSF (AUC = 3.3). Additional blackening of the walls of the KPro stem did not further diminish forward scatter significantly. If the holding lens is made translucent by sandblasting (to simulate an in vivo carrier cornea) and the KPro is inserted without a backplate, forward scatter is substantial (AUC = 11.3). If a standard backplate (with holes) is added, light scatter is considerably reduced regardless of whether the backplate is made of polymethyl methacrylate or titanium (AUC = 5.3 and 4.4, respectively). Addition of an acrylic intraocular lens behind the KPro (the pseudophakic KPro setup) did not increase scatter. CONCLUSIONS: Most of the scattered light in eyes implanted with a KPro originates from the surrounding hazy corneal graft. The standard addition of a backplate reduces light scatter. There was no difference in forward light scatter between the aphakic and the pseudophakic KPro.

Electrical Stimulation of the Trigeminal Ganglion and Intrathecal Drug Delivery Systems for the Management of Corneal Neuropathic Pain.

PURPOSE: This case study reports on 2 novel neuromodulatory approaches in the management of a particularly recalcitrant case of corneal neuropathic pain. METHODS: Report of a case RESULTS: : A 32-year-old woman presented with intractable bilateral dry eye-like symptoms and corneal neuropathic pain after undergoing laser in situ keratomileusis surgery. Extensive ocular and systemic therapies were unsuccessful. Implantation of an electrode for the electrical stimulation of the trigeminal ganglion resulted in complete resolution of symptoms, but pain recurred after lead migration. Implantation of an intrathecal infusion system for fentanyl and bupivacaine delivery at the C1-C2 level resulted in control of her symptoms with excellent pain relief for more than 1 year. CONCLUSIONS: Electrical stimulation of the trigeminal ganglion and a high cervical intrathecal pain pump can be used in the management of corneal neuropathic pain unresponsive to ocular and systemic approaches.

Successful Management of Corneal Neuropathic Pain with Intrathecal Targeted Drug Delivery.

OBJECTIVE: To describe the successful treatment of refractory corneal neuropathic pain with neuromodulation techniques. DESIGN: Single case report. SETTING: Academic tertiary care center in the United States of America. SUBJECT AND METHODS: A 30-year-old woman presented with a 7-year history of refractory bilateral keratoneuralgia following laser-assisted in-situ keratomileusis (LASIK) procedure on both eyes. Having failed all conservative measures, the patient initially underwent trigeminal nerve stimulation and subsequently was implanted with an intrathecal drug delivery system (IDDS) with the catheter placed at the level C1. RESULTS: Following an initial favorable response to the trigeminal nerve stimulator, the pain became refractory to neurostimulation after a few months and the system was explanted. The patient was successfully trialed with an intrathecal catheter placed at the level of C1 delivering a combination of bupivacaine and low dose fentanyl. The patient was then implanted with an IDDS equipped with a patient-activated bolus system. The patient was very satisfied with the treatment and has had greater than 50% pain relief for over a year. CONCLUSIONS: Intrathecal delivery of bupivacaine and low dose fentanyl in the upper cervical spine can be effective in controlling refractory eye pain in properly selected patients and treatment centers.

The Boston keratoprosthesis provides a wide depth of focus.

PURPOSE: To measure the through-focus curve for eyes implanted with a type 1 Boston keratoprosthesis (KPro) and compare it to that of pseudophakic controls with fixed pupil sizes. The results should assist in evaluating postoperative visual quality after surgery. They should also help to determine the necessary KPro inventories in terms of refractive power steps. METHODS: Autorefraction and manifest refraction were performed on all eyes. The monocular through-focus acuity curve was plotted in reference to the best-corrected visual acuity by spectacle plane defocus ranging from +5.00 to -5.00 dioptres in 0.50 dioptre increments. These measurements were obtained on KPro-implanted eyes, pseudophakic eyes as controls, and on the same control eyes after fixing the pupil diameter to 3 and 2 mm using black painted iris contact lenses. RESULTS: Ten KPro eyes and five control eyes were included. Good agreement was noted between the subjective refractions and autorefraction in KPro eyes. The average through-focus curve for the control eyes was significantly steeper than that of the KPro curve, but became comparable after fixing the control pupil to 2 and 3 mm. CONCLUSION: The KPro's wide depth-of-focus makes the visual acuity less dependent on an exact refractive correction at distance and explains the 'pseudoaccomodation' experienced by these patients. This is primarily due to the small pupil diameter of the KPro. The current manufacturing steps in 0.50 dioptre increments appears to be sufficient.

Very low risk of light-induced retinal damage during Boston keratoprosthesis surgery: a rabbit study.

PURPOSE: The aim of this study was to assess the possibility of light damage to the retina by a surgical microscope during implantation of a Boston Keratoprosthesis (B-KPro) in rabbits. METHODS: The retinal irradiance from a Zeiss OPMI Lumera S7 operating microscope was measured at the working distance (16.5 cm). Light transmittance through an isolated B-KPro was measured. A B-KPro was implanted into 1 eye of 12 rabbits with the optic covered during the procedure. The operated eyes were then continuously exposed to a fixed light intensity under the microscope for 1 hour. Fluorescein angiography was carried out on days 2 and 9 postsurgery, after which the animals were euthanized. Further, we compared the potential of these retinal exposures to well-accepted light safety guidelines applicable to humans. RESULTS: Light transmittance of B-KPro revealed a blockage of short wavelengths (<390 nm) and of long wavelengths (1660-1750 nm) of light. In addition, the surgical microscope filtered a part of the blue, ultraviolet, and infrared wavelengths. Neither fluorescein angiography nor a histological examination showed any morphological retinal changes in our rabbits. Moreover, the retinal exposures were well below the safety limits. CONCLUSIONS: Modern surgical microscopes have filters incorporated in them that block the most damaging wavelengths of light. The B-KPro is made of 100% poly(methyl methacrylate), which makes it in itself a blocker of short wavelengths of light. No damage could be demonstrated in the animal study, and the retinal exposures were well below the safety limits. Together, these results suggest that light exposures during B-KPro surgery present a low risk of photochemical damage to the retina.

Cocaine-assisted epithelial debridement for the treatment of anterior basement membrane dystrophy.

PURPOSE: To describe a method of epithelial debridement with the adjunctive use of topical cocaine for the treatment of symptomatic anterior basement membrane dystrophy (ABMD). METHODS: Retrospective consecutive chart review. Symptomatic patients with ABMD were treated with 4% topical cocaine followed by epithelial debridement. Preoperative and postoperative best-corrected visual acuities (BCVA), topography, subjective symptoms, complications, and evidence of disease recurrence were recorded. RESULTS: Thirty-three eyes of 27 patients were included. The average follow-up duration was 5 years (range, 1.3 months to 8 years). Fourteen patients (17 eyes) presented with recurrent erosion symptoms (group 1) and 13 patients (16 eyes) presented with reduced visual acuity from irregular astigmatism (group 2). Only 1 patient from group 1 experienced symptomatic recurrence of the corneal erosion. In this group, BCVA improved from a mean of 20/45 preoperatively to 20/38 at the last follow-up visit. In group 2, BCVA improved from a mean of 20/63 preoperatively to 20/32 at the last follow-up visit. No major recurrences were noted at the last follow-up visit in this group. No residual effect from the application of cocaine was noted in any of the eyes. Significant postoperative corneal haze occurred in 1 eye. CONCLUSIONS: Topical cocaine-assisted epithelial debridement offers a simple and inexpensive method for treating patients with ABMD who experience recurrent corneal erosions and/or irregular astigmatism resulting in decreased visual acuity.

Wide-angle fundus imaging through the Boston keratoprosthesis.

PURPOSE: To explore the feasibility and compare the outcomes of three wide-angle fundus cameras for imaging the peripheral retina through the Type 1 Boston keratoprosthesis. METHODS: The noncontact Optos and the contact RetCam and Panoret wide-angle imaging systems were used to image the retina of eyes implanted with a keratoprosthesis. The failure-to-image rate, ease of acquisition, and quality of the images were noted, and the field of view was compared. Limitations and complications were recorded. Optos was then performed on patients referred for ultrasound B-scan evaluation, and the imaging findings were correlated. RESULTS: Retinal images with all three cameras were obtained on four eyes. Optos could be performed on all four eyes, RetCam on three, and Panoret on two. The field of view was comparable between the three different cameras. The best quality images were obtained with Optos. The external illumination of the Panoret made it impossible to image the only darkly pigmented individual in the series. Both contact devices failed to image another patient who was too agitated. Two patients had some ocular irritation from the coupling agent that resolved with replacement of the contact lens. Optos images were obtained on an additional six eyes, and findings correlated well with those on B-scan. Optos was superior to B-scan in an eye with silicone oil filling. CONCLUSION: Wide-angle fundus imaging through the keratoprosthesis is possible, and all three cameras performed similarly. The good quality of pictures obtained with the noncontact Optos, as well as its ease of use, comfort, and safety make it a preferred choice. Optos complements B-scan in the examination of the peripheral retina through the keratoprosthesis, and it may even be superior in certain settings.

Practical applications of anterior segment optical coherence tomography imaging following corneal surgery.

Anterior segment optical coherence tomography (AS-OCT) has recently emerged as an important modality for imaging of the cornea. Since its introduction less than a decade ago, it has been clinically used for the diagnosis and management of an expanding number of corneal conditions. In this review, we will discuss the applications of anterior segment optical coherence tomography after corneal surgery, focusing on penetrating and lamellar keratoplasty, keratoprosthesis, intracorneal ring segments, collagen cross-linking and refractive surgery. Anterior segment optical coherence tomography is useful in evaluating outcomes, detecting adverse events, determining prognosis, guiding management decisions, and surgical planning.