Ocular inflammation is one of the leading causes of blindness worldwide, and steroids in topical ophthalmic solutions (e.g. dexamethasone eye drops) are the mainstay of therapy for ocular inflammation. For many non-infectious ocular inflammatory diseases, such as uveitis, eye drops are administered as often as once every hour. The high frequency of administration coupled with the side effects of eye drops leads to poor adherence for patients. Drug-eluting contact lenses have long been sought as a potentially superior alternative for sustained ocular drug delivery; but loading sufficient drug into contact lenses and control the release of the drug is still a challenge. A dexamethasone releasing contact lens (Dex-Lens) was previously developed by encapsulating a dexamethasone-polymer film within the periphery of a hydrogel-based contact lens. Here, we demonstrate safety and efficacy of the Dex-Lens in rabbit models in the treatment of anterior ocular inflammation. The Dex-Lens delivered drug for 7 days in vivo (rabbit model). In an ocular irritation study (Draize test) with Dex-Lens extracts, no adverse events were observed in normal rabbit eyes. Dex-Lenses effectively inhibited suture-induced corneal neovascularization and inflammation for 7 days and lipopolysaccharide-induced anterior uveitis for 5 days. The efficacy of Dex-Lenses was similar to that of hourly-administered dexamethasone eye drops. In the corneal neovascularization study, substantial corneal edema was observed in rabbit eyes that received no treatment and those that wore a vehicle lens as compared to rabbit eyes that wore the Dex-Lens. Throughout these studies, Dex-Lenses were well tolerated and did not exhibit signs of toxicity. Dexamethasone-eluting contact lenses may be an option for the treatment of ocular inflammation and a platform for ocular drug delivery. STATEMENT OF SIGNIFICANCE: Inflammation of the eye can happen either on the ocular surface (i.e. the cornea) or inside the eye, both of which can result in loss of vision or even blindness. Ocular inflammation is normally treated by steroid eye drops. Depending on the type and severity of inflammation, patients may have to take drops every hour for days at a time. Such severe dosing regimen can lead to patients missing doses. Also, more than 95% drug in an eye drop never goes inside the eye. Here we present a contact lens that release a steroid (dexamethasone) for seven days at a time. It is much more efficient than eye drops and a significant improvement since once worn, the patient will avoid missing doses.
Purpose: The purpose of this study was to visualize the lamina cribrosa (LC) capillaries and collagenous beams, measure capillary tortuosity (path length over straight end-to-end length), and determine if capillary tortuosity changes when intraocular pressure (IOP) increases. Methods: Within 8 hours of sacrifice, 3 pig heads were cannulated via the external ophthalmic artery, perfused with PBS to remove blood, and then perfused with a fluorescent dye to label the capillaries. The posterior pole of each eye was mounted in a custom-made inflation chamber for control of IOP with simultaneous imaging. Capillaries and collagen beams were visualized with structured light illumination enhanced imaging at IOPs from 5 to 50 mm Hg at each 5 mm Hg increment. Capillary tortuosity was measured from the images and paired two-sample t-tests were used to assess for significant changes in relation to changes in IOP. Results: Capillaries were highly tortuous at 15 mm Hg (up to 1.45). In all but one eye, tortuosity decreased significantly as IOP increased from 15 to 25 mm Hg (P < 0.01), and tortuosity decreased significantly in every eye as IOP increased from 15 to 40 mm Hg (P < 0.01). In only 16% of capillaries, tortuosity increased with elevated IOP. Capillaries had a surprisingly different topology from the collagen beams. Conclusions: Although high capillary tortuosity is sometimes regarded as potentially problematic because it can reduce blood flow, LC capillary tortuosity may provide slack that mitigates against reduced flow and structural damage caused by excessive stretch under elevated IOP. We speculate that low capillary tortuosity could be a risk factor for damage under high IOP.
BACKGROUNDHyperglycemia, insulin insensitivity, and low IGF1 levels in extremely preterm infants are associated with an increased risk of retinopathy of prematurity (ROP), but the interactions are incompletely understood.METHODSIn 117 extremely preterm infants, serum glucose levels and parenteral glucose intake were recoded daily in the first postnatal week. Serum IGF1 levels were measured weekly. Mice with oxygen-induced retinopathy alone versus oxygen-induced retinopathy plus streptozotocin-induced hyperglycemia/hypoinsulinemia were assessed for glucose, insulin, IGF1, IGFBP1, and IGFBP3 in blood and liver. Recombinant human IGF1 was injected to assess the effect on glucose and retinopathy.RESULTSThe highest mean plasma glucose tertile of infants positively correlated with parenteral glucose intake [r(39) = 0.67, P < 0.0001]. IGF1 plasma levels were lower in the high tertile compared with those in low and intermediate tertiles at day 28 (P = 0.038 and P = 0.03). In high versus lower glucose tertiles, ROP was more prevalent (34 of 39 versus 19 of 39) and more severe (ROP stage 3 or higher; 71% versus 32%). In oxygen-induced retinopathy, hyperglycemia/hypoinsulinemia decreased liver IGF1 expression (P < 0.0001); rh-IGF1 treatment improved normal vascular regrowth (P = 0.027) and reduced neovascularization (P < 0.0001).CONCLUSIONIn extremely preterm infants, high early postnatal plasma glucose levels and signs of insulin insensitivity were associated with lower IGF1 levels and increased ROP severity. In a hyperglycemia retinopathy mouse model, decreased insulin signaling suppressed liver IGF1 production, lowered serum IGF1 levels, and increased neovascularization. IGF1 supplementation improved retinal revascularization and decreased pathological neovascularization. The data support IGF1 as a potential treatment for prevention of ROP.TRIAL REGISTRATIONClinicalTrials.gov NCT02760472 (Donna Mega).FUNDINGThis study has been supported by the Swedish Medical Research Council (14940, 4732, 20144-01-3, and 21144-01-3), a Swedish government grant (ALFGB2770), Lund medical faculty grants (ALFL, 11615 and 11601), the Skåne Council Foundation for Research and Development, the Linnéa and Josef Carlsson Foundation, the Knut and Alice Wallenberg Foundation, the NIH/National Eye Institute (EY022275, EY017017, EY017017-13S1, and P01 HD18655), European Commission FP7 project 305485 PREVENT-ROP, Deutsche Forschungsgemeinschaft (CA-1940/1-1), and Stiftelsen De Blindas Vänner.
PURPOSE: To review the published literature on the accuracy of ophthalmic imaging methods to differentiate between papilledema and pseudopapilledema in children. METHODS: Literature searches were conducted in January 2020 in the PubMed database for English-language studies with no date restrictions and in the Cochrane Library database without any restrictions. The combined searches yielded 354 abstracts, of which 17 were reviewed in full text. Six of these were considered appropriate for inclusion in this assessment and were assigned a level of evidence rating by the panel methodologist. All 6 included studies were rated as level III evidence. RESULTS: Fluorescein angiography, a combination of 2 OCT protocols, and multicolor confocal scanning laser ophthalmoscopy (Spectralis SD-OCT; Heidelberg Engineering, Heidelberg, Germany) demonstrated the highest positive percent agreement (92%-100%; 95% confidence interval [CI], 69%-100%) and negative percent agreement (92%-100%; 95% CI, 70%-100%) with a clinical diagnosis of papilledema in children. However, results must be interpreted with caution owing to methodologic limitations, including a small sample size leading to wide CIs and an overall lack of data (there was only 1 study each for the above methods and protocols). Ultrasonographic measures showed either a high positive percent agreement (up to 95%) with low negative percent agreement (as low as 58%) or vice versa. Autofluorescence and fundus photography showed a lower positive (40%-60%) and negative (57%) percent agreement. CONCLUSIONS: Although several imaging methods demonstrated high positive and negative percent agreement with clinical diagnosis, no ophthalmic imaging method conclusively differentiated papilledema from pseudopapilledema in children because of the lack of high-quality evidence. Clinicians must continue to conduct thorough history-taking and examination and make judicious use of ancillary testing to determine which children warrant further workup for papilledema.
Glaucoma is a frequent and devastating long-term complication following ocular trauma, including corneal surgery, open globe injury, chemical burn, and infection. Postevent inflammation and neuroglial remodeling play a key role in subsequent ganglion cell apoptosis and glaucoma. To this end, this study was designed to investigate the amplifying role of monocyte infiltration into the retina. By using three different ocular injury mouse models (corneal suture, penetrating keratoplasty, and globe injury) and monocyte fate mapping techniques, we show that ocular trauma or surgery can cause robust infiltration of bone marrow-derived monocytes into the retina and subsequent neuroinflammation by up-regulation of Tnf, Il1b, and Il6 mRNA within 24 hours. This is accompanied by ganglion cell apoptosis and neurodegeneration. Prompt inhibition of tumor necrosis factor-α or IL-1β markedly suppresses monocyte infiltration and ganglion cell loss. Thus, acute ocular injury (surgical or trauma) can lead to rapid neuroretinal inflammation and subsequent ganglion cell loss, the hallmark of glaucoma. Infiltrating monocytes play a central role in this process, likely amplifying the inflammatory cascade, aiding in the activation of retinal microglia. Prompt administration of cytokine inhibitors after ocular injury prevents this infiltration and ameliorates the damage to the retina-suggesting that it may be used prophylactically for neuroprotection against post-traumatic glaucoma.
PURPOSE: To investigate via volumetric analysis whether orbital fat atrophy occurs in late post-traumatic enophthalmos. METHODS: An IRB-approved retrospective cohort study identified patients with diagnoses of both orbital fracture and enophthalmos with a CT orbits >3 months after injury. Exclusion criteria were surgical repair, other orbital disease or surgery, adjacent sinus disease, and an abnormal contralateral orbit. Images were analyzed using OsiriX imaging software (v.9.0.2, Pixmeo, Switzerland). Total orbital volume and orbital fat volume for the fractured and normal contralateral orbits were measured via three-dimensional volume rendering assisted region-of-interest computation. Enophthalmos was measured radiographically. Paired samples -tests were used to compare orbital fat and total orbital volumes between the fractured and normal contralateral orbits. RESULTS: Thirteen patients met the inclusion criteria. The numbers of patients with each fracture pattern were floor (4), medial wall (4), floor/medial wall (3), zygomaticomaxillary complex (floor+lateral wall) (1), zygomaticomaxillary complex+medial (inferior/medial/lateral walls) (1). Mean time from injury to CT scan was 21.8 ± 16.3 months. Comparing the fractured and normal contralateral orbits, there was a statistically significant decrease in orbital fat volume (mean difference 0.9 ml (14.2%), = .0002) and increase in total orbital volume (mean difference 2.0 ml (7.0%), = .0001). One ml orbital volume change was responsible for 0.83 mm enophthalmos. CONCLUSIONS: In addition to an increase in total orbital volume, orbital fat loss occurs with late post-traumatic enophthalmos due to unrepaired fractures. This suggests correction of bony change alone may be insufficient in some cases, and the use of custom implants may compensate for fat atrophy.
PURPOSE: In recent decades, the medical and surgical treatment of limbal stem cell deficiency (LSCD) has evolved significantly through the incorporation of innovative pharmacological strategies, surgical techniques, bioengineering, and cell therapy. With such a wide variety of options, there is a need to establish a global consensus on the preferred approaches for the medical and surgical treatment of LSCD. METHODS: An international LSCD Working Group was established by the Cornea Society in 2012 and divided into subcommittees. Four face-to-face meetings, frequent email discussions, and teleconferences were conducted since then to reach agreement on a strategic plan and methods after a comprehensive literature search. A writing group drafted the current study. RESULTS: A consensus in the medical and surgical management of LSCD was reached by the Working Group. Optimization of the ocular surface by eyelid and conjunctival reconstruction, antiinflammatory therapy, dry eye and meibomian gland dysfunction treatment, minimization of ocular surface toxicity from medications, topical medications that promote epithelialization, and use of a scleral lens is considered essential before surgical treatment of LSCD. Depending on the laterality, cause, and stage of LSCD, surgical strategies including conjunctival epitheliectomy, amniotic membrane transplantation, transplantation of limbal stem cells using different techniques and sources (allogeneic vs. autologous vs. ex vivo-cultivated), transplantation of oral mucosal epithelium, and keratoprosthesis can be performed as treatment. A stepwise flowchart for use in treatment decision-making was established. CONCLUSIONS: This global consensus provides an up-to-date and comprehensive framework for the management of LSCD.
OBJECTIVE: To determine the most commonly used and highest-rated mobile applications (apps) for low-vision aids. METHODS: This was a convenience sample survey. Patients known to use low-vision apps at a nonprofit low-vision center (INSIGHT, Warwick, RI) were contacted by phone between June and September 2019. INCLUSION CRITERIA: age 18+, Snellen visual acuity (VA) below 20/70, and the use of low-vision mobile apps for at least one month. A standardized script was used to record survey data and app ratings were evaluated by patients with a scale of one to five, one being the lowest and five being the highest. RESULTS: Of the sample (n=11), nine patients (81.8%) stated they used an iPhone for low-vision mobile apps. A list of 14 mobile apps was identified: the two most commonly used apps were Seeing AI (81.8%) and Be My Eyes (63.6%); their average ratings were 4.43/5 and 4.75/5, respectively. CONCLUSIONS: This survey suggests that Seeing AI and Be My Eyes are useful apps to help low- vision patients with activities of daily living.
The neural mechanism of phantom limb pain (PLP) is related to the intense brain reorganization process implicating plasticity after deafferentation mostly in sensorimotor system. There is a limited understanding of the association between the sensorimotor system and PLP. We used a novel task-based functional magnetic resonance imaging (fMRI) approach to (1) assess neural activation within a-priori selected regions-of-interested (motor cortex [M1], somatosensory cortex [S1], and visual cortex [V1]), (2) quantify the cortical representation shift in the affected M1, and (3) correlate these changes with baseline clinical characteristics. In a sample of 18 participants, we found a significantly increased activity in M1 and S1 as well as a shift in motor cortex representation that was not related to PLP intensity. In an exploratory analyses (not corrected for multiple comparisons), they were directly correlated with time since amputation; and there was an association between increased activity in M1 with a lack of itching sensation and V1 activation was negatively correlated with PLP. Longer periods of amputation lead to compensatory changes in sensory-motor areas; and itching seems to be a protective marker for less signal changes. We confirmed that PLP intensity is not associated with signal changes in M1 and S1 but in V1.
OBJECTIVES: 1) To elucidate the role of collector channels in the aqueous humor outflow pathway 2) To suggest anatomic and functional methods of imaging collector channels in-vitro and in-vivo and 3) To discuss the role of such imaging modalities in the surgical management of glaucoma. METHODS: A thorough literature search was conducted on databases for studies published in English regarding the available methods to determine the role of collecting channels in normal and glaucomatous patients and to assess their patency. RESULTS: Intraocular pressure (IOP) exists as a balance between aqueous humor production and aqueous humor outflow. Collector channels are an essential anatomical constituent of the distal portion of the conventional aqueous humor outflow pathway. There are different surgical options for glaucoma management and with the recent advances in Schlemm's canal-based surgeries, collector channel's patency became a key factor in determining the optimum management for the glaucomatous eye. The advent of anatomic imaging methods has improved the ability to visualize collector channel morphology in-vitro, including swept-source optical coherence tomography (SS-OCT), spectral domain optical coherence tomography (SD-OCT), micro-computed tomography (micro CT), new immunohistochemistry techniques and scanning electron microscopy. The recent advent of real-time assessment of collector channel patency (including evaluation of episcleral venous outflow, observation of episcleral venous fluid wave, and tracer studies utilizing fluorescein, indocyanine green, and trypan blue) has been validated by the aforementioned anatomic imaging modalities. CONCLUSIONS: New modalities of in-vitro and in-vivo studies of collector channels provide promise to aid in the assessment of collector channel patency and individualization of surgical management for glaucoma patients.
PURPOSE: To report the incidence of symptomatic vertical and torsional diplopia after superior rectus transposition (SRT) for esotropic Duane syndrome and abducens nerve palsy. METHODS: The medical records of patients with esotropic Duane syndrome or abducens nerve palsy seen at Boston Children's Hospital (2006-2018) and treated with unilateral SRT with or without augmentation was performed. The primary outcome was incidence of postoperative vertical or torsional diplopia in primary position. The secondary outcome was induced vertical deviation in affected side gaze. RESULTS: A total of 69 patients met inclusion criteria: 32 with abducens nerve palsy and 37 with esotropic Duane syndrome. Vertical alignment changed in both hyper- and hypotropic directions. Median pre- and postoperative vertical deviation in primary gaze was 1.1 (10th-90th percentile, 0-6 hypertropia) and 0.4 (10th-90th percentile, 6 hypotropia to 8 hypertropia), respectively. Postoperative vertical diplopia occurred in 7%, including 4 of 49 treated with loop myopexy (8%), 1 of 13 without augmentation (8%), and 0 of 7 treated with sclera-fixated augmentation. All but one was successfully treated with prism or secondary surgery. Intorsional change predominated, but no patient had torsional diplopia post adjustment. Vertical misalignment in affected side gaze increased from 19% to 45% after SRT (P = 0.01). CONCLUSIONS: In this largest-to-date review of patients treated with SRT, with or without MR recession, no patient developed persistent torsional diplopia, while 7% developed symptomatic vertical diplopia in primary position, similar to the reported incidence after balanced vertical rectus transposition. Vertical misalignment in affected side gaze increased, however fusion is already limited by unresolved esotropia in this field.
The purpose of this study was to determine the pathogenic changes that occur in myoepithelial cells (MECs) from lacrimal glands of a mouse model of Sjögren syndrome. MECs were cultured from lacrimal glands of C57BL/6J [wild type (WT)] and thrombospondin 1 null (TSP1, alias Thbs1) mice and from mice expressing α-smooth muscle actin-green fluorescent protein that labels MECs. MECs were stimulated with cholinergic and α-adrenergic agonists, vasoactive intestinal peptide (VIP), and the purinergic agonists ATP and UTP. Then intracellular [Ca] was measured using fura-2, and contraction was observed using live cell imaging. Expression of purinergic receptors was determined by Western blot analysis, and mRNA expression was analyzed by microarray. The increase in intracellular [Ca] with VIP and UTP was significantly smaller in MECs from TSP1 compared with WT mice. Cholinergic agonists, ATP, and UTP stimulated contraction in MECs, although contraction of MECs from TSP1 mice was reduced compared with WT mice. The amount of purinergic receptors P2Y1, P2Y11, and P2Y13 was significantly decreased in MECs from TSP1 compared with WT mice, whereas several extracellular matrix and inflammation genes were up-regulated in MECs from TSP1 mice. We conclude that lacrimal gland MEC function is altered by inflammation because the functions regulated by cholinergic agonists, VIP, and purinergic receptors are decreased in TSP1 compared with WT mice.
Importance: Optic neuritis (ON) in children is uncommon. There are limited prospective data for visual acuity (VA) outcomes, associated diseases, and neuroimaging findings. Prospective data from a large sample would be useful for counseling families on treatment decisions and prognosis. Objective: To prospectively study children with a first episode of ON, describe VA after 6 months, and ascertain the network's (Pediatric Eye Disease Investigator Group and Neuro-Ophthalmology Research Disease Investigator Consortium) ability to enroll pediatric patients with ON prospectively. Design, Setting, and Participants: This nonrandomized cohort study was conducted from September 20, 2016, to July 20, 2018, at 23 sites in the United States and Canada in pediatric ophthalmology or neuro-ophthalmology clinics. A total of 44 children (aged 3-15 years) presented with a first episode of ON (visual loss, pain on eye movements, or both) within 2 weeks of symptom onset and at least 1 of the following in the affected eye: a distance high-contrast VA (HCVA) deficit of at least 0.2 logMAR below age-based norms, diminished color vision, abnormal visual field, or optic disc swelling. Exclusion criteria included preexisting ocular abnormalities or a previous episode of ON. Main Outcomes and Measures: Primary outcomes were monocular HCVA and low-contrast VA at 6 months. Secondary outcomes were neuroimaging, associated diagnoses, and antibodies for neuromyelitis optica and myelin oligodendrocyte glycoprotein. Results: A total of 44 children (mean age [SD], 10.2 [3.5] years; 26 boys [59%]; 23 White individuals [52%]; 54 eyes) were enrolled in the study. Sixteen patients (36%) had bilateral ON. Magnetic resonance imaging revealed white matter lesions in 23 children (52%). Of these children, 8 had myelin oligodendrocyte glycoprotein-associated demyelination (18%), 7 had acute disseminated encephalomyelitis (16%), 5 had multiple sclerosis (11%), and 3 had neuromyelitis optica (7%). The baseline mean HCVA was 0.95 logMAR (20/200), which improved by a mean 0.76 logMAR (95% CI, 0.54-0.99; range, -0.70 to 1.80) to 0.12 logMAR (20/25) at 6 months. The baseline mean distance low-contrast VA was 1.49 logMAR (20/640) and improved by a mean 0.72 logMAR (95% CI, 0.54-0.89; range, -0.20 to 1.50) to 0.73 logMAR (20/100) at 6 months. Baseline HCVA was worse in younger participants (aged <10 years) with associated neurologic autoimmune diagnoses, white matter lesions, and in those of non-White race and non-Hispanic ethnicity. The data did not suggest a statistically significant association between baseline factors and improvement in HCVA. Conclusions and Relevance: The study network did not reach its targeted enrollment of 100 pediatric patients with ON over 2 years. This indicates that future treatment trials may need to use different inclusion criteria or plan a longer enrollment period to account for the rarity of the disease. Despite poor VA at presentation, most children had marked improvement by 6 months. Associated neurologic autoimmune diagnoses were common. These findings can be used to counsel families about the disease.
Viral vectors have a great potential for gene delivery, but manufacturing at a pharmaceutical scale is a big challenge for the industry. The baculovirus-insect cell system is one of the most scalable platforms to produce clinical-grade recombinant Adeno-Associated Virus (rAAV) vectors. The standard procedure to generate recombinant baculovirus is based on Tn7 transposition which is time-consuming and still suffers technical constraints. Moreover, werecently showed that baculoviral sequences adjacent to the AAV ITRs are preferentially encapsidated into the rAAV vector particles. This observation raised concerns about safety for clinical applications due to the presence of bacterial and antibiotic resistance coding sequences with a Tn7-mediated system for the construction of baculoviruses reagents. Here, weinvestigated a faster and safer method based on homologous recombination (HR). First, weconfirmed the functionality of the inserted cassette and the absence of undesirable genes into HR-derived baculoviral genomes. Strikingly, wefound that the exogenous cassette showed increased stability over passages when using the HR system. Finally, wetested these materials to produce rAAV vectors. The baculoviruses originated from both systems lead to high rAAV vector genome yields, with the advantage of the HR system being exempted from undesirable bacterial genes which provides an additional level of safety for the manufacturing of rAAV vectors. Overall, this study highlights the importance of the upstream process and starting biologic materials to generate safer rAAV biotherapeutic products. This article is protected by copyright. All rights reserved.
BACKGROUND: Glaucoma is one of the leading causes of blindness worldwide. Treatment is still largely targeted at lowering intraocular pressure. Intraocular pressures can be lowered through a variety of topical medications, lasers and incisional surgeries. There are currently several classes of topical medications available in the US that are aimed at lowering intraocular pressure through a variety of different mechanisms. Additionally, there have been numerous different formulations and fixed-dose combination medications that offer greatly expanded treatment options over the last several years. The wide variety of topical medications aim to address the issues with compliance, effectiveness and side effect profile that vary among each individual patient and disease. Purpose: Three new topical medications, netarsudil 0.02%, latanoprostene bunod 0.24% and fixed-dose combination netarsudil 0.02% - latanoprost 0.005% have been approved in the US market to treat glaucoma. This review article will summarize the studies looking at their effectiveness and side effect profiles and discuss their utilization in the treatment of glaucoma. Additionally, we will briefly discuss future directions of research in topical glaucoma medications. CONCLUSION: Three new topical glaucoma medications offer additional treatment options for patient with glaucoma. Further research is needed to better understand the utility of sustained release formulations in the treatment of glaucoma.
PRECIS: In open-angle glaucoma, when neuroretinal rim tissue measured by volumetric optical coherence tomography (OCT) scans is below a third of the normal value, visual field (VF) damage becomes detectable. PURPOSE: To determine the amount of neuroretinal rim tissue thickness below which VF damage becomes detectable. METHODS: In a retrospective cross-sectional study, 1 eye per subject (of 57 healthy and 100 open-angle glaucoma patients) at an academic institution had eye examinations, VF testing, spectral-domain OCT retinal nerve fiber layer (RNFL) thickness measurements, and optic nerve volumetric scans. Using custom algorithms, the minimum distance band (MDB) neuroretinal rim thickness was calculated from optic nerve scans. "Broken-stick" regression was performed for estimating both the MDB and RNFL thickness tipping-point thresholds, below which were associated with initial VF defects in the decibel scale. The slopes for the structure-function relationship above and below the thresholds were computed. Smoothing curves of the MDB and RNFL thickness covariates were evaluated to examine the consistency of the independently identified tipping-point pairs. RESULTS: Plots of VF total deviation against MDB thickness revealed plateaus of VF total deviation unrelated to MDB thickness. Below the thresholds, VF total deviation decreased with MDB thickness, with the associated slopes significantly greater than those above the thresholds (P<0.014). Below 31% of global MDB thickness, and 36.8% and 43.6% of superior and inferior MDB thickness, VF damage becomes detectable. The MDB and RNFL tipping points were in good accordance with the correlation of the MDB and RNFL thickness covariates. CONCLUSIONS: When neuroretinal rim tissue, characterized by MDB thickness in OCT, is below a third of the normal value, VF damage in the decibel scale becomes detectable.