July 2023

Corneal diseases are among the most common causes of blindness worldwide. Regardless of the etiology, corneal opacity- or globe integrity-threatening conditions may necessitate corneal replacement procedures. Several procedure types are currently available to address these issues, based on the complexity and extent of injury. Corneal allograft or keratoplasty is considered to be first-line treatment in many cases. However, a significant proportion of the world's population are reported to have no access to this option due to limitations in donor preparation. Thus, providing an appropriate, safe, and efficient synthetic implant (e.g., artificial cornea) may revolutionize this field. Nanotechnology, with its potential applications, has garnered a lot of recent attention in this area, however, there is seemingly a long way to go. This narrative review provides a brief overview of the therapeutic interventions for corneal pathologies, followed by a summary of current biomaterials used in corneal regeneration and a discussion of the nanotechnologies that can aid in the production of superior implants.

SIGNIFICANCE: Veridical depictions of scene appearance with scotomas allow better understanding of the impact of field loss and may improve the development and implementation of rehabilitation. Explanation and depiction of the invisibility of scotoma may lead to patients' understanding and thus better compliance with related treatments. PURPOSE: Simulations of perception with scotomas guide training, patient education, and rehabilitation research. Most simulations incorrectly depict scotomas as black patches, though the scotomas and the missing contents are usually invisible to patients. We present a novel approach to capture the reported appearance of scenes with scotomas. METHODS: We applied a content-aware image resizing algorithm to carve out the content elided under the scotoma. With video sequences we show how and why eye movements fail to increase the visibility of the carved scotomas. RESULTS: Numerous effects, reported by patients, emerge naturally from the scotoma carving. Carving-eliminated scotomas over natural images are barely visible, despite causing substantial distortions. Low resolution and contrast sensitivity at farther eccentricities and saccadic blur reduce the visibility of the distortions. In a walking scenario, static objects moving smoothly to the periphery disappear into, and then reemerge out of peripheral scotomas invisibly. CONCLUSIONS: Scotoma carving provides a viable hypothetical simulation of vision with scotomas, due to loss of neurons at the retinal ganglion cell level and higher. As a hypothesis, it generates predictions that lend themselves to future clinical testing. The different effects of scotomas due to loss of photoreceptors are left for follow-up work.

We describe an atypical presentation of aberrant regeneration of the 3rd cranial nerve causing vision changes with ocular motility. Abnormal communication between axons destined for the medial rectus and those destined for muscles involved in the accommodative response resulted in simultaneous pupil constriction and myopic shift of approximately 2.5 diopters with adduction. While there have been several reports of this pupillary response (Czarnecki sign), no cases have documented the change in refraction from ciliary muscle involvement.

OBJECTIVES: The Coronavirus Disease 2019 (COVID-19) pandemic led to the expansion of virtual medicine as a method to provide patient care. We aimed to determine the impact of pediatric and young adult virtual medicine use on fossil fuel consumption, greenhouse gas and non-greenhouse traffic-related air pollutant emissions. METHODS: We conducted a retrospective analysis of all virtual medicine patients at a single quaternary-care children's hospital with a geocoded address in the Commonwealth of Massachusetts prior to (3/16/2019-3/15/2020) and during the COVID-19 pandemic (3/16/2020-3/15/2021). Primary outcomes included patient travel distance, gasoline consumption, carbon dioxide and fine particulate matter emissions as well as savings in main hospital energy use. RESULTS: There were 3,846 and 307,273 virtual visits performed with valid Massachusetts geocoded addresses prior to and during the COVID-19 pandemic, respectively. During one year of the pandemic, virtual medicine services resulted in a total reduction of 620,231 gallons of fossil fuel use and $1,620,002 avoided expenditure as well as 5,492.9 metric tons of carbon dioxide and 186.3 kilograms of fine particulate matter emitted. There were 3.1 million fewer kilowatt hours used by the hospital intra-pandemic compared to the year prior. Accounting for equipment emissions, the combined intra-pandemic emission reductions are equivalent to the electricity required by 1,234 homes for one year. CONCLUSIONS: Widespread pediatric institutional use of virtual medicine provided environmental benefits. The true potential of virtual medicine for decreasing the environmental footprint of healthcare lies in scaling this mode of care to patient groups across the state and nation when medically feasible.

BACKGROUND: Glaucoma secondary to familial exudative vitreoretinopathy presents as angle closure by either neovascular or non-neovascular mechanisms. We analyze the presentation and outcomes of two types of childhood glaucoma secondary to familial exudative vitreoretinopathy (FEVR). METHODS: This retrospective cross-sectional study included all patients <18 years of age diagnosed with glaucoma after or concurrently with a diagnosis of FEVR between 2010 and 2020 from Queen Sirikit National Institute of Child Health in Bangkok, Thailand. Two groups were analyzed: neovascular or non-neovascular angle-closure status. Primary outcome measures were final visual acuity and intraocular pressure (IOP) in both groups. RESULTS: Of 144 FEVR patients, 8 children (5.5%; 11 eyes, 3 bilateral cases) developed childhood glaucoma. Mean time between FEVR presentation and glaucoma was 42.2 ± 40.0 months. In the neovascular group, 3 of 9 eyes presented with glaucoma at FEVR diagnosis; 3 of 9 eyes (33%) required glaucoma surgery. In the non-neovascular group, 2 eyes presented with acute angle closure secondary to a phacomorphic lens. Both were treated with trabeculectomy, with resolution of pupillary block. All eyes had stage 4B FEVR or greater. Six of 8 eyes had stable or better visual acuity, and 10 eyes (91%) had IOP <21 mm Hg at final follow-up. CONCLUSIONS: Childhood glaucoma secondary to FEVR is a rare complication caused by later stages of the disease. It may present as neovascular or non-neovascular angle closure, often requiring complex care. Therefore, awareness and adequate management of FEVR can help prevent additional morbidity from childhood glaucoma.

PURPOSE: The Paul glaucoma implant (PGI, Advanced Ophthalmic Innovations, Singapore, Republic of Singapore) is a recently developed novel non-valved glaucoma drainage device (GDD) designed to effectively reduce the intraocular pressure (IOP) in glaucoma patients with a theoretically reduced risk of postoperative complications such as hypotony, endothelial cell loss, strabismus, and diplopia. Limited literature has evaluated its use in adult glaucoma; however, its use in pediatric glaucoma has not been reported to date. We present our early experience with PGI in refractory childhood glaucoma. PATIENTS AND METHODS: This study was retrospective single-surgeon case series in a single tertiary center. RESULTS: Three eyes of 3 patients with childhood glaucoma were enrolled in the study. During nine months of follow-up, postoperative IOP and number of glaucoma medications were significantly lower than preoperative values in all the enrolled patients. None of the patients developed postoperative complications including postoperative hypotony, choroidal detachment, endophthalmitis, or corneal decompensation. CONCLUSION: PGI is an efficient and relatively safe surgical treatment option in patients with refractory childhood glaucoma. Further studies with larger number of participants and longer follow-up period are required to confirm our encouraging results.

PURPOSE: To highlight a potential alternative to additional surgery for management of retinal re-detachment through the use of additional facedown positioning with silicone oil tamponade. METHODS: Retrospective case-series of two patients evaluated with examination, multimodal imaging, including fundus photography, optical coherence tomography (OCT), and fluorescein angiography. RESULTS: In case 1, a 70-year-old female patient underwent surgery for a full-thickness macular hole with associated macula-off retinal detachment, but experienced a recurrent detachment and underwent a second surgery with silicone oil placement. Another recurrent detachment was found. The case was managed conservatively with face-down positioning, resulting in resolution of subretinal fluid and improvement in vision. At follow-up, the retina remained attached with stable vision. In case 2, a 25-year-old male patient underwent a surgical repair for PVR retinal detachment with a scleral buckle, cryotherapy, and external drainage. After multiple re-detachment surgeries with retinectomy and oil placement there was another tractional re-detachment of the fovea was noted. Management was with facedown positioning and follow-up evaluation showed resolution of the subretinal fluid and improvement in vision with stability for greater than 2 months. CONCLUSIONS: For recurrent retinal re-detachments with silicone oil in place, an additional week of facedown positioning can result in anatomic success and be a viable alternative or bridge to invasive surgical interventions. This approach may have greatest utility for patients who are poor surgical candidates without new peripheral pathology.

PURPOSE: To evaluate available rationale and outcomes of randomized trial results for complement inhibition for geographic atrophy. METHODS: Data from recently completed randomized trials of complement inhibition, particularly for pegcetacoplan and avacincaptad pegol, were evaluated for both the outcome, area of autofluorescence loss, and functional vision tests. RESULTS: Pegcetacoplan 2 mg showed statistically significant reduction in expansion of the area of autofluorescence loss with monthly, but not every-other-month dosing, in a 12-month phase two trial. Nearly 40% of patients recruited for the monthly arm did not complete the treatment. In two parallel phase 3 studies there was a statistically significant reduction in the area of atrophy in one but not both studies as compared with untreated controls. Data released at 24 months follow-up showed statistically significant reduction in the area of autofluorescence-detected atrophy in both studies compared with sham. Patients did not show functional difference in best-corrected visual acuity, maximum reading speed, Functional Reading Independence Index, and mean microperimetry threshold sensitivities in the treatment versus sham arms. Avacincaptad pegol was evaluated in two randomized pivotal studies and showed a statistically significant reduction in the expansion of autofluorescence loss at 12 months. Patients in the treatment arms did not show any difference as compared with sham in the best-corrected visual acuity or low luminance visual acuity, the only functional outcomes mentioned. Both drugs increased the risk of macular neovascularization. CONCLUSION: Both avacincaptad pegol and pegcetacoplan show significant differences compared with sham in autofluorescence imaging but no benefit in visual function at 12 and 24 months, respectively.

Adaptive optics provides improved resolution in ophthalmic imaging when retinal microstructures need to be identified, counted, and mapped. In general, multiple images are averaged to improve the signal-to-noise ratio or analyzed for temporal dynamics. Image registration by cross-correlation is straightforward for small patches; however, larger images require more sophisticated registration techniques. Strip-based registration has been used successfully for photoreceptor mosaic alignment in small patches; however, if the deformations along strips are not simple displacements, averaging can degrade the final image. We have applied a non-rigid registration technique that improves the quality of processed images for mapping cones over large image patches. In this approach, correction of local deformations compensates for local image stretching, compressing, bending, and twisting due to a number of causes. The main result of this procedure is improved definition of retinal microstructures that can be better identified and segmented. Derived metrics such as cone density, wall-to-lumen ratio, and quantification of structural modification of blood vessel walls have diagnostic value in many retinal diseases, including diabetic retinopathy and age-related macular degeneration, and their improved evaluations may facilitate early diagnostics of retinal diseases.

PURPOSE: To determine the prevalence and types of pathogens found in children with orbital cellulitis and to evaluate the utility of nonoperative cultures. METHODS: This was a retrospective cohort study of children with imaging-confirmed orbital cellulitis over a period of 8 years. Outcomes included prevalence and types of organisms, polymicrobial infection, mixed aerobic-anaerobic infection, effect of age, and culture utility. RESULTS: Of 220 children with orbital cellulitis, 112 (51%) had cultures taken; 69 (31%) had surgical intervention. Culture sources for the 112 children with cultures included blood (57 patients [51%]), sinus (53 [47%]), orbit (42 [38%]), brain (6 [5%]), and skin/conjunctiva/lacrimal sac (6 [5%]). Streptococcus anginosus group strains grew in cultures from 19 children (17%); methicillin-sensitive Staphylococcus aureus (MSSA), in 15 (13%); Streptococcus pyogenes, in 12 (11%); methicillin-resistant Staphylococcus aureus (MRSA), in 6 (5%); anaerobic/facultative gram negative rods, in 8 (7%); anaerobic Gram-positive cocci, other Viridans group streptococci, and Streptococci pneumoniae, in 3 (3%) each; and normal respiratory/skin flora, in 23 (21%). Polymicrobial infection (P = 0.08) and anaerobic organisms (P = 0.58) did not differ by age (range, 0.1-16.8 years). In all 220 (100%) children, nonoperative cultures were either not obtained (108 [49%]), not helpful in avoiding surgery (69 [31%]), showed no growth (39 [18%]), or grew an organism that did not change management from empiric therapy (4 [2%]). CONCLUSIONS: While many organisms may be cultured from children with orbital cellulitis, Streptococcus and MSSA were the most common in our study cohort. MRSA is uncommon, so initial empiric coverage is not necessary. Rates of polymicrobial and anaerobic infection were similar across ages. Our results indicate that nonoperative cultures are not indicated in the initial medical management of orbital cellulitis; in our cohort, they neither resulted in treatment changes nor helped avoid surgery.

Retinitis pigmentosa is a blinding disease wherein rod photoreceptors are affected first, due to the expression of a disease gene, leading to the loss of dim light vision. In many cases, cones do not express the disease gene, yet they are also affected and eventually die, typically after most of the rods in their neighborhood have died. The cause of secondary cone death is unclear. Photoreceptors are one of the most energy-demanding cell types in the body and consume a high amount of glucose. At an early stage of degeneration, the cones appear to have a shortage of glucose to fuel their metabolism. This review focuses on gene therapy approaches that address this potential metabolic shortcoming.

PURPOSE: To describe a novel technique for cataract surgery in patients with iris coloboma. METHODS: The technique involves 1) creation of an inferiorly displaced capsulorrhexis and 2) amputation of one intraocular lens (IOL) haptic, thus allowing for controlled IOL decentration in the direction of an inferior iris defect. RESULTS: We report favorable outcomes in two eyes (one patient) where eccentric capsulorrhexis and haptic amputation were employed during one-piece IOL repositioning in one eye and cataract surgery with three-piece IOL implantation in the contralateral eye. CONCLUSION: In coloboma patients who are asymptomatic from their iris defect and do not have a cosmetic desire for repair, eccentric capsulorrhexis and IOL haptic amputation is a viable surgical option that allows for the preservation of a clear visual axis without the need for iris repair.