Recovery From Homonymous Hemianopia in Hyperglycemia-Induced Occipital Lobe Electroclinical Seizures Following Glycemic Control.

BACKGROUND: Visual changes due to hyperglycemia in diabetes are not uncommon. While blurred vision is a well-established sequela of chronic hyperglycemia, homonymous hemianopia with or without electroclinical seizures is much rarer and can be mistaken for migraine, temporal arteritis, or ischemia of the central nervous system. METHODS: This article analyzed case studies for 3 patients (67M, 68M, 52F) presenting with complex visual phenomena, from 3 to 42 days duration, including pathogenesis, clinical findings, management, and follow-up. RESULTS: Examinations demonstrated dense left homonymous hemianopias in 2 patients and a left inferior homonymous quadrantanopia in one, with no other abnormalities. Patients described vivid, nonstereotyped intermittent hallucinations in the affected fields. Blood glucose levels ranged from 13.5 to 35.0 mmol/L (243-630 mg/dL) without ketosis and HbA1c from 14.6% to 16.8%. Computed tomography of the brain showed no acute intracranial pathology. MRI of the brain either detected no abnormalities or demonstrated changes consistent with seizure activity. Electroencephalogram (EEG) demonstrated seizures over the right occipital region in each patient. EEG seizures coincided with patients' hallucinations, while they remained otherwise conscious. Oral hypoglycemic and antiepileptic medications were commenced with rapid and complete reversal of the seizures and visual field deficits, confirmed by repeat Automated 30-2 and MRI. CONCLUSIONS: Hyperglycemia-induced occipital lobe seizures with visual hallucinations and interictal homonymous visual field defects represent a rare but clinically important diagnosis. This article highlights the importance of prompt recognition and treatment to facilitate recovery.

A Systematic Review of Ophthalmology Education in Medical Schools: The Global Decline.

TOPIC: This systematic review examined geographical and temporal trends in medical school ophthalmology education in relationship to course and student outcomes. CLINICAL RELEVANCE: Evidence suggesting a decline in ophthalmology teaching in medical schools is increasing, raising concern for the adequacy of eye knowledge across the rest of the medical profession. METHODS: Systematic review of Embase and SCOPUS, with inclusion of studies containing data on medical school ophthalmic course length; 1 or more outcome measures on student ophthalmology knowledge, skills, self-evaluation of knowledge or skills, or student course appraisal; or both. The systematic review was registered prospectively on the International Prospective Register of Systematic Reviews (identifier, CRD42022323865). Results were aggregated with outcome subgroup analysis and description in relationship to geographical and temporal trends. Descriptive statistics, including nonparametric correlations, were used to analyze data and trends. RESULTS: Systematic review yielded 4596 publication titles, of which 52 were included in the analysis, with data from 19 countries. Average course length ranged from 12.5 to 208.7 hours, with significant continental disparity among mean course lengths. Africa reported the longest average course length at 103.3 hours, and North America reported the shortest at 36.4 hours. On average, course lengths have been declining over the last 2 decades, from an average overall course length of 92.9 hours in the 2000s to 52.9 hours in the 2020s. Mean student self-evaluation of skills was 51.3%, and mean student self-evaluation of knowledge was 55.4%. Objective mean assessment mark of skills was 57.5% and that of knowledge was 71.7%, compared with an average pass mark of 66.7%. On average, 26.4% of students felt confident in their ophthalmology knowledge and 34.5% felt confident in their skills. DISCUSSION: Most evidence describes declining length of courses devoted to ophthalmology in the last 20 years, significant student dissatisfaction with courses and content, and suboptimal knowledge and confidence. FINANCIAL DISCLOSURE(S): Proprietary or commercial disclosure may be found in the Footnotes and Disclosures at the end of this article.

Aqueous Humor Circulation in the Era of Minimally Invasive Surgery for Glaucoma.

Glaucoma surgery with implantation of aqueous humor draining microstents may compromise long-term corneal health by disrupting aqueous humor circulation. The effect of stent numbers on this circulation was interrogated to determine the number of stents associated with minimal circulation disruption. An in vitro anterior eye model perfusion system was constructed with multiple exit ports. A 3-D model of the anterior eye was imported into ABAQUS CFD, analyzes were carried out for unsteady laminar flow and solved using Navier-Stokes equations. DT Vision Foundry was used to analyze velocity contour plot images. The field variable results output for the CFD model were fluid wall shear, fluid pressure and fluid velocity. In vitro, "aqueous" fluid flow is high through a single stent and "aqueous" stagnation is greatest in the quadrants 180° away. Increasing stent port numbers, results in an exponential decrease in the stagnant flow locations. High wall shear stress was seen in the single stent model and is markedly reduced after a second and subsequent stents are introduced. We identify two factors potentially contributing to corneal compromise post glaucoma drainage surgery: aqueous humor stagnation, remote to the stent site and higher exit flows imparting increased stent exit shear stress (particularly with a single stent). With 4 stents, there is minimal disruption of anterior chamber circulation (mimicking physiological conditions). Furthermore we propose that aqueous humor circulation disruption via the usual single-exit port approach disrupts aqueous humor circulation with long-term consequences for corneal health.

Modified Limbal-Conjunctival Autograft Surgical Technique: Long-Term Results of Recurrence and Complications.

PURPOSE: The aim of this study was to report the recurrence and complication rates of a modified limbal-conjunctival autograft surgical technique for pterygium excision. METHODS: This was a retrospective, single-surgeon, single-operating environment, consecutive case series of 176 eyes in 163 patients with a biopsy-proven diagnosis of pterygium. All patients underwent excision using a 23-gauge needle to "behead" the pterygium head, followed by a limbal-conjunctival autograft including ∼50% of the palisades of Vogt. Outcomes measured included recurrence, defined as any conjunctival fibrovascular growth, and complication rates. Correlations between preoperative patient characteristics, pterygium morphology, and intraoperative factors (width of corneal extension, conjunctival defect, and graft) with postoperative recurrence were examined using logistic regression models. RESULTS: The median age was 59.5 years and 122 eyes (69.3%) had primary pterygium (type I: 17%, II: 37.5%, and III: 45.5%). Kaplan-Meier analysis demonstrated the median pterygium-free follow-up period to be 723 days (range 46-7230 days). Recurrence was observed in 3 eyes of 2 patients (1.7%). No postoperative graft-related complications were observed. Postoperative symptomatology was transient. Age demonstrated a negative correlation with recurrence (odds ratio 0.888, 95% CI, 0.789-0.998, P = 0.046). However, no other correlations with preoperative or intraoperative factors, including whether pterygium was primary or recurrent, were identified (all P > 0.05). CONCLUSIONS: This modified limbal-conjunctival autograft technique represents an effective alternative that offers a very low recurrence rate and avoids extensive dissection or antimetabolites, with minimal complications and transient postoperative symptomatology, over a long-term follow-up period. This technique is relatively simple and successful for both primary and recurrent pterygia. Future comparative studies with other surgical techniques may determine which are superior.

Case Series of Rare Fungal Keratitides: Experiences from a Quaternary Eye Hospital in Sydney, Australia.

The present article reports on the management of six different and rare cases of fungal keratitides, two of which have never been documented in previous literature. This is a case series of six patients with rare fungal keratitides managed at a quaternary eye referral unit, Sydney Eye Hospital, Australia over a period of 7 months (May to December, 2022). The order of occurrence of fungi isolated was Scedosporium apiospermum, Lomenstospora prolificans, Cladosporium spp., Paecilomyces, Syncephalastrum racemosum and Quambalaria spp. A combination of medical and surgical interventions was employed, including topical and systemic anti-fungal therapy, with one requiring therapeutic penetrating keratoplasty and another eventuating in evisceration. Two patients were successfully treated with corneal debridement and two others required pars plana vitrectomy with anterior chamber washout. It is important to remain vigilant with monitoring patient symptoms and correlating with clinical signs to guide antifungal therapy even in the context of confirmed culture and sensitivity results.

Zonular and capsular bag disorders: a hypothetical perspective based on recent pathophysiological insights.

The purpose of this article was to look at the pathophysiology behind and devise a classification system for the causes of zonular apparatus-capsular bag (ZACB) insufficiency. Also discussed is dystrophic bag syndrome, including clinical cases and addressing where it lies on the ZACB spectrum. There has been interest in the emergence of in-the-bag intraocular lens (IOL) subluxation, the prevalence of which is increasing. There has also been a recent report of dead bag syndrome, which the authors believe is part of the same disease spectrum. The authors put these phenomena into perspective and provide a classification system based on the possible causes of what they have termed ZACB insufficiency. The basic aspects of capsular bag-IOL ocular pathophysiology are summarized with a focus on functional aspects and the consequences for IOL fastening. Within this framework, dystrophic bag syndrome is a form of primary capsular ZACB insufficiency. The contribution of factors such as intraocular drugs may suggest a reconsideration of agents used and their mode of application.

A systematic review on the effects of ROCK inhibitors on proliferation and/or differentiation in human somatic stem cells: A hypothesis that ROCK inhibitors support corneal endothelial healing via acting on the limbal stem cell niche.

Rho kinase inhibitors (ROCKi) have attracted growing multidisciplinary interest, particularly in Ophthalmology where the question as to how they promote corneal endothelial healing remains unresolved. Concurrently, stem cell biology has rapidly progressed in unravelling drivers of stem cell (SC) proliferation and differentiation, where mechanical niche factors and the actin cytoskeleton are increasingly recognized as key players. There is mounting evidence from the study of the peripheral corneal endothelium that supports the likelihood of an internal limbal stem cell niche. The possibility that ROCKi stimulate the endothelial SC niche has not been addressed. Furthermore, there is currently a paucity of data that directly evaluates whether ROCKi promotes corneal endothelial healing by acting on this limbal SC niche located near the transition zone. Therefore, we performed a systematic review examining the effects ROCKi on the proliferation and differentiation of human somatic SC, to provide insight into its effects on various human SC populations. An appraisal of electronic searches of four databases identified 1 in vivo and 58 in vitro studies (36 evaluated proliferation while 53 examined differentiation). Types of SC studied included mesenchymal (n = 32), epithelial (n = 11), epidermal (n = 8), hematopoietic and other (n = 8). The ROCK 1/2 selective inhibitor Y-27632 was used in almost all studies (n = 58), while several studies evaluated ≥2 ROCKi (n = 4) including fasudil, H-1152, and KD025. ROCKi significantly influenced human somatic SC proliferation in 81% of studies (29/36) and SC differentiation in 94% of studies (50/53). The present systemic review highlights that ROCKi are influential in regulating human SC proliferation and differentiation, and provides evidence to support the hypothesis that ROCKi promotes corneal endothelial division and maintenance via acting on the inner limbal SC niche.

Conjunctival ultraviolet autofluorescence area decreases with age and sunglasses use.

BACKGROUND: Conjunctival ultraviolet autofluorescence (CUVAF) is a method of detecting conjunctival damage related to ultraviolet radiation exposure. In cross-sectional studies, CUVAF area is positively associated with self-reported time spent outdoors and pterygium and negatively associated with myopia; however, longitudinal studies are scarce. AIMS: To use a novel deep learning-based tool to assess 8-year change in CUVAF area in young adults, investigate factors associated with this change and identify the number of new onset pterygia. METHODS: A deep learning-based CUVAF tool was developed to measure CUVAF area. CUVAF area and pterygium status were assessed at three study visits: baseline (participants were approximately 20 years old) and at 7-year and 8-year follow-ups. Participants self-reported sun protection behaviours and ocular history. RESULTS: CUVAF data were available for 1497 participants from at least one study visit; 633 (43%) participants had complete CUVAF data. Mean CUVAF areas at baseline and the 7-year and 8-year follow-ups were 48.4, 39.3 and 37.7 mm2, respectively. There was a decrease in mean CUVAF area over time (change in total CUVAF area=-0.96 mm2 per year (95% CI: -1.07 to -0.86)). For participants who wore sunglasses ≥1/2 of the time, CUVAF area decreased by an additional -0.42 mm2 per year (95% CI: -0.72 to -0.12) on average. Fourteen (1.5%) participants developed a pterygium. CONCLUSIONS: In this young adult cohort, CUVAF area declined over an 8-year period. Wearing sunglasses was associated with a faster reduction in CUVAF area. Deep learning-based models can assist in accurate and efficient measurement of CUVAF area.

Was Marilyn Monroe myopic and an early adopter of colored contact lenses? A review of the evidence and the early history of colored contact lenses.

Wide availability and uptake of contact lenses came with the development of the first polymethyl methacrylate corneal lenses during the late 1940s. It is less well known that colored contact lenses were developed simultaneously. These innovations allowed both a degree of spectacle independence for ametropes and an ability to vary eye color. The impact on facial and ocular cosmesis was substantial, particularly for public figures such as actors. We have obtained contact lenses and matching casts manufactured by their inventor, Kevin M. Tuohy. Measurements of these suggest they were made for a myope, and we provide indirect evidence that the lenses were made for Marilyn Monroe. We also provide evidence that Monroe is likely to have been myopic, used colored contact lenses to change her eye color and may have been an early sufferer of contact lens overwear syndrome. The importance of ocular cosmesis can be overlooked in ophthalmic practice, yet it is of great interest to and importance for patients. It appears that discomfort, and even risk, will be tolerated to achieve a particular appearance. This is reflected in current techniques aimed at achieving improved cosmesis.

Electron Microscopy and Elemental Analysis of Defective Drysdale Nucleus Manipulator Instruments Implicated in Surgical Complications.

PURPOSE: To analyze microtopography of 5 reusable Drysdale nucleus manipulator (DNM) paddled tips for sharp defects and evaluate their elemental composition to determine probable source, investigating 2 instruments (DNM 1 and 4) implicated in causing posterior capsule rupture (PCR) and 3 instruments with sharp edges identified by finger-tip interrogation intraoperatively. DESIGN: Experimental laboratory investigation. METHODS: DNM paddled tips were analyzed using scanning electron microscopy (SEM) to evaluate for sharp surface defects (number, dimensions), and subsequently energy dispersive x-ray spectroscopy (EDS) performed on sharp defects to determine their elemental composition. RESULTS: All reused DNMs analyzed (5 of 5) had significant structural defects on SEM analysis including sharp burrs, cavities and indentations, surface debris or residues, and roughening, compared to the new instrument (DNM 3, control) which had no defects. DNM 1 had 2 sharp defects, a larger 14 × 76-µm one and a craterlike 167 × 220-µm defect containing debris. EDS found that DNM 2 had 3 of 4 burrs composed mainly of carbon, the fourth of mixed composition (calcium, sulfur, oxygen); DNM 4 had 1 small burr, EDS significant for carbon; DNM 5 had 3 prominent burrs, the largest of 20 × 28 µm, 2 composed of aluminum, and some carbon residue. DNM 6 had 1 burr composed of aluminum and 3 prominent cavity defects, the largest covering 781 µm2. CONCLUSION: Reusable DNMs are widely used in cataract surgery. Sharp carbon- or aluminum-containing burrs were detected on all reused instruments analyzed together with 1 burr of mixed composition, originating from (1) organic residues, (2) instrument fragments, or (3) salt and contaminant deposits. Sharp defects may contribute to capsular damage including PCR, and residues may pose other safety concerns. Therefore, we support development of a quality, reliable single-use alternative instrument and further encourage careful inspection of all reusable instruments principally by finger-tip interrogation for sharp edges preuse.

5-Fluorouracil in primary, impending recurrent and recurrent pterygium: Systematic review of the efficacy and safety of a surgical adjuvant and intralesional antimetabolite.

Pterygium is an ultraviolet-related disease characterized by an aberrant, wing-shaped and active wound-healing process. There is nothing quite as disheartening for the surgeon or patient as the recurrence of pterygium, and various adjuvants have been studied to ameliorate this. This systematic review provides a comprehensive summary of the efficacy and safety of 5-Fluorouracil (5-FU) as an antimetabolite agent for pterygium management. An appraisal of electronic searches of six databases identified 34 clinical studies reporting recurrence outcomes of 5-FU use in primary, impending recurrent and recurrent pterygia. In vitro and in vivo studies of 5-FU showed dose- and duration-dependent cytostatic and cytotoxic effects in human cells. 5-FU is relatively inexpensive, available, and easy to administer, making it attractive for resource-limited scenarios. However, the published evidence demonstrates a recurrence rate of 11.4-60% with the bare scleral technique, 3.5-35.8% with conjunctival rotational flaps, 3.7-9.6% with conjunctival autografts for intraoperative topical 5-FU, and 14-35.8% for preoperative and intraoperative injections. This suboptimal efficacy brings the role of 5-FU as an adjuvant for pterygium surgery into question and the authors do not recommend its use. In contrast, postoperative intralesional injections of 5-FU to arrest progression in impending recurrent pterygium and true recurrent pterygia were more promising, with success rates of 87.2-100% and 75-100%, respectively. Furthermore, 5-FU as a treatment modality, without surgery, effectively arrested progression in 81.3-96% of primary and recurrent pterygia. Other treatments such as topical and intralesional corticosteroids, cyclosporine and anti-VEGF agents are discussed. Complications of 5-FU increase with higher doses and range from transient and reversible to severe and sight-threatening. For pterygium, 5-FU has a predilection for causing scleral thinning, corneal toxicity, and graft-related complications. Additional study with extended follow-up is needed to elucidate the optimal dose, frequency, duration, and long-term safety of 5-FU injections. If 5-FU is used in the management of pterygium, it should be with caution, in selected patients and with vigilant long-term monitoring.

Pterygium and Ocular Surface Squamous Neoplasia: Optical Biopsy Using a Novel Autofluorescence Multispectral Imaging Technique.

In this study, differentiation of pterygium vs. ocular surface squamous neoplasia based on multispectral autofluorescence imaging technique was investigated. Fifty (N = 50) patients with histopathological diagnosis of pterygium (PTG) and/or ocular surface squamous neoplasia (OSSN) were recruited. Fixed unstained biopsy specimens were imaged by multispectral microscopy. Tissue autofluorescence images were obtained with a custom-built fluorescent microscope with 59 spectral channels, each with specific excitation and emission wavelength ranges, suitable for the most abundant tissue fluorophores such as elastin, flavins, porphyrin, and lipofuscin. Images were analyzed using a new classification framework called fused-classification, designed to minimize interpatient variability, as an established support vector machine learning method. Normal, PTG, and OSSN regions were automatically detected and delineated, with accuracy evaluated against expert assessment by a specialist in OSSN pathology. Signals from spectral channels yielding signals from elastin, flavins, porphyrin, and lipofuscin were significantly different between regions classified as normal, PTG, and OSSN (p < 0.01). Differential diagnosis of PTG/OSSN and normal tissue had accuracy, sensitivity, and specificity of 88 ± 6%, 84 ± 10% and 91 ± 6%, respectively. Our automated diagnostic method generated maps of the reasonably well circumscribed normal/PTG and OSSN interface. PTG and OSSN margins identified by our automated analysis were in close agreement with the margins found in the H&E sections. Such a map can be rapidly generated on a real time basis and potentially used for intraoperative assessment.

Lens Epithelial Cell Removal in Routine Phacoemulsification: Is It Worth the Bother?

PURPOSE: To review the literature on crystalline lens epithelial cell (LEC) removal in routine phacoemulsification and determine whether it should be incorporated as part of a surgeon's standard technique. DESIGN: Perspective. METHODS: Expert commentary with video demonstrations on techniques of removal of LECs and associated potential complications. Discussion incorporates the importance of LEC removal, a review of techniques to prevent posterior capsular opacification (PCO), and the effects of intraocular lens design on LEC proliferation and PCO. RESULTS: The evidence suggests that LEC removal should be routinely performed as it can be carried out safely and with considerable short- and long-term benefits for patients. With effective cleanup, there is reduced anterior capsule opacification, fibrosis, and decentration of the capsular bag as well as reduced rates of posterior capsular opacification. Techniques for removal are easy to learn, with very low complication rates, and can reduce the risk of the long-term need for technically complex procedures such as intraocular lens explantation. CONCLUSIONS: LEC removal from both the anterior and posterior capsule is part of a continuous, incremental improvement of cataract surgery and should be introduced to ophthalmology trainees during their formative years as part of their regular cataract surgery armamentarium.

Intraocular lens explantation following cataract surgery: Indications, techniques, and video demonstrations.

As techniques for modern cataract surgery have expanded and premium intraocular lens (IOL) use is now widespread, patient expectations are high. The need for IOL explantation, whilst still low, remains an ongoing issue. Intraocular lens explantation can be challenging for a number of reasons and as such we have introduced an additional technique to add to the surgeon's repertoire. Bimanual haptic stripping of fibrosis at the specific area where the haptic is adherent to the capsular bag is an effective strategy to aid in dissection of haptics without compromising the capsule or zonules. Given the challenges associated with IOL explantation, newly designed IOLs need to avoid these "sticking points" at which the IOLs interact with the fibrosed capsule. Techniques we have evolved and which are described below should assist anterior segment surgeons to facilitate IOL removal in an efficient and safe way.

Subpalpebral Antibiotic Lavage as Safe, Emergent, and Cost-Effective Management of Acute Infectious Keratitis Related to Contact Lens Overwear: Case Report and Literature Review.

PURPOSE: The aim of this study is to describe the technique of subpalpebral antibiotic lavage (SAL), which is a highly therapeutic, efficient, and cost-effective method for managing severe bacterial keratitis. METHODS: This case report describes a 26-year-old woman with severe bacterial keratitis in the right eye due to contact lens overwear, with progressive corneal thinning, a hypopyon, impending perforation, and marked visual loss to perception of light despite treatment with intensive topical antibiotics. This was managed with SAL that involves the insertion of a cannula transcutaneously into the upper conjunctival fornix to provide continuous antibiotic irrigation of the ocular surface. RESULTS: By 11 weeks after presentation, the cornea and anterior chamber appeared clinically quiescent, and visual acuity improved to 20/40 corrected in the right eye. CONCLUSIONS: Bacterial keratitis is a potentially blinding condition for which contact lens wear is an important risk factor. Most cases are successfully managed with topical medications; however, in cases of treatment failure, a second-line approach such as SAL can be sight-saving. SAL uses readily available equipment for the delivery of high concentrations of antibiotics to the ocular surface, thus increasing therapeutic efficacy and reducing nursing staff workload. Despite its advantages, the literature reveals apparent underutilization of this technique.

Irritable bowel syndrome and risk of glaucoma: An analysis of two independent population-based cohort studies.

OBJECTIVE: Irritable bowel syndrome (IBS) is a chronic disorder associated with an abnormal gastrointestinal microbiome. Microbiome-host interactions are known to influence organ function including in the central nervous system; thus, we sought to identify whether IBS may be a risk factor for the development of glaucoma. DESIGN: Two prospective cohort studies. SUBJECTS: The 1958 United Kingdom Birth Cohort (UKBC; 9091 individuals) and the Danish National Registry of Patients (DNRP; 62,541 individuals with IBS and 625,410 matched general population cohort members). METHODS: In the UKBC, participants were surveyed throughout life (including at ages 42 and 50). The DNRP contains records of hospital-based contacts and prescription data from the national prescription database. MAIN OUTCOME MEASURE: The main outcome measure was incidence of glaucoma. In the UKBC, incident glaucoma at age 50 (n = 48) was determined through comparison of survey responses at ages 42 and 50 years. In the DNRP, glaucoma was assessed by hospital diagnosis (n = 1510), glaucoma surgery (n = 582) and initiation of glaucoma medications (n = 1674). RESULTS: In the UKBC, the odds ratio (OR) of developing glaucoma between ages 42 and 50 in persons with a chronic IBS diagnosis was increased [OR: 5.84, 95% confidence interval (CI): 2.26-15.13]. People with an IBS diagnosis in the DNRP had a hazard ratio (HR) of 1.35 for developing physician-diagnosed glaucoma (95% CI: 1.16-1.56), an HR of 1.35 for undergoing glaucoma surgery (95% CI: 1.06-1.70) and an HR of 1.19 for initiating glaucoma medication (95% CI: 1.03-1.38). CONCLUSIONS: In two large European cohort studies, IBS is a risk factor for glaucoma.

Spontaneous face- and eye-touching: Infection risk versus potential microbiome gain.

The COVID-19 pandemic has piqued interest in spontaneous face-touch as a possible route of microbial infection, with eye-touch of particular importance since the ocular surface is a likely portal of human Coronavirus infection. Spontaneous face-touching is a poorly understood, ingrained habit for humans, who engage in this activity on average between 9 to 162 times per hour. Nearly half of spontaneous face-touches involve mucous membranes, and one third of those involve the eyes. The infective sequelae of self-touch are well documented in ophthalmological conditions such as infectious conjunctivitis, with risks for ocular surface disease beyond primary infection from pathogens such as human papillomavirus. Through tear film conveyance via the nasolacrimal duct, ocular surface pathogens may furthermore have access to the nasopharynx, oropharynx, and respiratory/gastrointestinal systems beyond. Ocular surface and face self-touch therefore represent a concerning possible method of not only local, but also systemic, self-inoculation. Conversely, microbial diversity in the mutualistic microbiome is being increasingly implicated as integral for developing immunity, and protecting against endocrinological and neurodegenerative disease, including those that affect the eye. Spontaneous face-touch brings the hands, the part of the body most in contact with the external world and with the highest temporal diversity, into direct contact with the body's multiple microbiomes. The authors hypothesise that spontaneous self-touch may represent an important mechanism by which the skin, ocular surface, gastrointestinal, and respiratory tracts maintains microbial diversity and prevents dysbiosis. It may be that whilst the eyes are at risk of infection through self-touch, they may paradoxically benefit through the acquisition of a mutualistic microbiome, protective not only for the eyes, but for the body as a whole.