Anatomical characterization of central, apical and minimal corneal thickness

<b>AIM:</b> To anatomically locate the points of minimum corneal thickness and central corneal thickness (pupil center) in relation to the corneal apex.<b>METHODS:</b> Observational, cross-sectional study, 299 healthy volunteers. Thickness at the corneal apex (AT), minimum corneal thickness (MT) and corneal thickness at the pupil center (PT) were determined using the pentacam. Distances from the corneal apex to MT (MD) and PT (PD) were calculated and their quadrant position (taking the corneal apex as the reference) determined:point of minimum thickness (MC) and point of central thickness (PC) depending on the quadrant position. Two multivariate linear regression models were constructed to examine the influence of age, gender, power of the flattest and steepest corneal axes, position of the flattest axis, corneal volume (determined using the Pentacam) and PT on MD and PD. The effects of these variables on MC and PC were also determined in two multinomial regression models.<b>RESULTS:</b> MT was located at a mean distance of 0.909 mm from the apex (79.4% in the inferior-temporal quadrant). PT was located at a mean distance of 0.156 mm from the apex. The linear regression model for MD indicated it was significantly influenced by corneal volume (B=-0.024; 95%CI:-0.043 to -0.004). No significant relations were identified in the linear regression model for PD or the multinomial logistic regressions for MC and PC.<b>CONCLUSION:</b> MT was typically located at the inferior-temporal quadrant of the cornea and its distance to the corneal apex tended to decrease with the increment of corneal volume

Chronic Glaucoma Using Biodegradable Microspheres to Induce Intraocular Pressure Elevation. Six-Month Follow-Up

Altres ajuts: Rio Hortega Research Grant M17/00213, Research Group UCM 920415, UCM-Santander fellowship (CT17/17-CT17-18).Background: To compare two prolonged animal models of glaucoma over 24 weeks of follow-up. A novel pre-trabecular model of chronic glaucoma was achieved by injection of biodegradable poly lactic-co-glycolic acid (PLGA) microspheres (10-20 µm) (Ms20/10) into the ocular anterior chamber to progressively increase ocular hypertension (OHT). Methods: Rat right eyes were injected to induce OHT: 50% received a suspension of Ms20/10 in the anterior chamber at 0, 2, 4, 8, 12, 16 and 20 weeks, and the other 50% received a sclerosing episcleral vein injection biweekly (EPIm). Ophthalmological clinical signs, intraocular pressure (IOP), neuroretinal functionality measured by electroretinography (ERG), and structural analysis of the retina, retinal nerve fiber layer (RNFL) and ganglion cell layer (GCL) protocols using optical coherence tomography (OCT) and histological exams were performed. Results: Both models showed progressive neuroretinal degeneration (p < 0.05), and contralateral eye affectation. The Ms20/10 model showed a more progressive increase in IOP and better preservation of ocular surface. Although no statistical differences were found between models, the EPIm showed a tendency to produce thicker retinal and thinner GCL thicknesses, slower latency and smaller amplitude as measured using ERG, and more aggressive disturbances in retinal histology. In both models, while the GCL showed the greatest percentage loss of thickness, the RNFL showed the greatest and earliest rate of thickness loss. Conclusions: The intracameral model with biodegradable microspheres resulted more like the conditions observed in humans. It was obtained by a less-aggressive mechanism, which allows for adequate study of the pathology over longer periods

Analysis of parainflammation in chronic glaucoma using vitreous-oct imaging

Glaucoma causes blindness due to the progressive death of retinal ganglion cells. The immune response chronically and subclinically mediates a homeostatic role. In current clinical practice, it is impossible to analyse neuroinflammation non-invasively. However, analysis of vitreous images using optical coherence tomography detects the immune response as hyperreflective opacities. This study monitors vitreous parainflammation in two animal models of glaucoma, comparing both healthy controls and sexes over six months. Computational analysis characterizes in vivo the hyperreflective opacities, identified histologically as hyalocyte-like Iba-1+ (microglial marker) cells. Glaucomatous eyes showed greater intensity and number of vitreous opacities as well as dynamic fluctuations in the percentage of activated cells (50–250 microns2 ) vs. non-activated cells (10–50 microns2 ), isolated cells (10 microns2) and complexes (&gt;250 microns2 ). Smaller opacities (isolated cells) showed the highest mean intensity (intracellular machinery), were the most rounded at earlier stages (recruitment) and showed the greatest change in orientation (motility). Study of vitreous parainflammation could be a biomarker of glaucoma onset and progression. © 2021 by the authors. Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (https:// creativecommons.org/licenses/by/ 4.0/)

Role of GUCA1C in Primary Congenital Glaucoma and in the Retina: Functional Evaluation in Zebrafish

Primary congenital glaucoma (PCG) is a heterogeneous, inherited, and severe optical neuropathy caused by apoptotic degeneration of the retinal ganglion cell layer. Whole-exome sequencing analysis of one PCG family identified two affected siblings who carried a low-frequency homozygous nonsense GUCA1C variant (c.52G > T/p.Glu18Ter/rs143174402). This gene encodes GCAP3, a member of the guanylate cyclase activating protein family, involved in phototransduction and with a potential role in intraocular pressure regulation. Segregation analysis supported the notion that the variant was coinherited with the disease in an autosomal recessive fashion. GCAP3 was detected immunohistochemically in the adult human ocular ciliary epithelium and retina. To evaluate the ocular effect of GUCA1C loss-of-function, a guca1c knockout zebrafish line was generated by CRISPR/Cas9 genome editing. Immunohistochemistry demonstrated the presence of GCAP3 in the non-pigmented ciliary epithelium and retina of adult wild-type fishes. Knockout animals presented up-regulation of the glial fibrillary acidic protein in Müller cells and evidence of retinal ganglion cell apoptosis, indicating the existence of gliosis and glaucoma-like retinal damage. In summary, our data provide evidence for the role of GUCA1C as a candidate gene in PCG and offer new insights into the function of this gene in the ocular anterior segment and the retina.This research was funded by research grants from the “Instituto de Salud Carlos III/European Regional Development Fund (ERDF)” (PI15/01193, PI19/00208 and RD16/0008/0019, OFTARED), the Regional Ministry of Science and Technology of the Board of the Communities of “Castilla-La Mancha” (SBPLY/17/180501/000404; http://www.educa.jccm.es/idiuniv/es). SA-M was sponsored by the Regional Ministry of Science and Technology of the Board of the Communities of “Castilla-La Mancha” (PREJCCM2016/28)

Clinical Evaluation of the New Rebound Tonometers Icare PRO and Icare ONE Compared With the Goldmann Tonometer

To compare the participant-obtained intraocular pressures (IOPs) using Icare ONE and the clinician-obtained values using Icare PRO, both rebound tonometers, with Goldmann tonometry (GAT) values and analyze the ease of use of Icare ONE. One hundred fifty participants were included (60 normal controls, 90 patients with glaucoma/ocular hypertension). The participants measured the IOP 3 times using Icare ONE; a clinician measured the IOP once using Icare PRO. The instruments were used randomly. Clinical data were evaluated to analyze the difficulty of the technique, the effect on the results, and the ease of use of Icare ONE. The mean IOPs with GAT, Icare ONE, and Icare PRO were 16.6±4.43, 17.5±5.42, and 16.6±4.77 mm Hg, respectively. The participant-measured IOP values were within +3 mm Hg of the GAT values in 67.1% of eyes with Icare ONE and in 79.6% with Icare PRO. The limits of agreement were higher with Icare ONE compared with Icare PRO. IOP value errors were found with Icare ONE in eyes with low and high GAT-IOP. The areas under the curve to detect IOPs of 21 mm Hg or higher (GAT) exceeded 0.80 with both tonometers. Young participants reported better ease of use with Icare ONE. No other factors were related to the results. Icare ONE may be useful for patients monitoring their IOP values; most individuals can use the device after a short training session. Icare PRO had better results compared with Icare ONE in all IOP ranges

Intense pulsed light-based treatment for the improvement of symptoms in glaucoma patients treated with hypotensive eye drops

Background: Ocular surface disease in glaucoma patients is a significant ocular co-morbidity that can affect 40% to 59% of these patients worldwide. The current study was aimed at evaluating the potential clinical benefit of an intense pulsed light (IPL)-based treatment in glaucomatous patients with ocular surface disease due to prolonged hypotensive eyedrop treatments. To our knowledge, this is the first series analyzing the therapeutic effect of this treatment option in this type of patients. Methods: This non-comparative prospective case series study enrolled a total of 30 glaucoma patients ranging in age from 57 to 94 years old and treated with hypotensive eyedrops for years with dry eye symptomatology. All patients received four sessions of IPL treatment using the Optima IPL system (Lumenis, Yokneam, Israel) adjusted to the official optimized Lumenis setting. Changes in symptomatology, corneal staining, conjunctival hyperemia, non-invasive break-up time (NIBUT), tear osmolarity, tear meniscus height (TMH), meiboscore and meibomian gland expressibility was analyzed after treatment. Results: Statistically significant reductions were observed after IPL treatment in the symptomatology scores measured with different questionnaires [ocular surface disease index (OSDI), standard patient evaluation of eye dryness (SPEED) and symptom assessment questionnaire in dry eye (SANDE)] as well as with the visual analogue scale (P < 0.001). Mean change in OSDI was − 15.0 ± 11.3. A significant reduction was found after treatment in the corneal staining score (P < 0.001). A significant reduction was found in tear film meniscus height (P = 0.012), as well as in tear film osmolarity (P = 0.001). A significant reduction was also found in meibomian gland expressibility (P = 0.003), changing the percentage of grade 3 eyes from 44.4% before IPL to 17.2% after treatment. Conclusions: IPL therapy combined with meibomian gland expression (MGX) seems to be an effective option to improve symptomatology in glaucomatous patients with ocular surface disease due to prolonged hypotensive eyedrop treatments, with an additional improvement in clinical signs, such as tear osmolarity and corneal staining

Easyton® transpalpebral versus Perkins applanation tonometry in different populations

Objective To compare intraocular pressure (IOP) measurements obtained using the new transpalpebral Easyton® tonometer and Perkins applanation tonometer (PAT) in three different clinical populations. Methods The participants of this prospective study were 84 subjects divided into the groups: 22 healthy children (G1), 42 healthy adults (G2), and 20 adult patients with primary open angle glaucoma (G3). The data recorded in 84 eyes of these subjects were age, sex, gender, central corneal thickness (CCT), and axial length (AL). In all eyes, IOP was determined in the same examination room by the same experienced examiner using Easyton® and PAT in random order. Results Mean differences in IOP readings between Easyton® and PAT were 0.45 ± 1.97 (p = 0.295), − 0.15 ± 2.13 (p = 0.654), − 1.65 ± 3.22 (p = 0.033), and − 0.018 ± 2.50 mmHg (p = 0.500) in the groups G1, G2, G3, and whole sample (G4), respectively. Correlations between Easyton® and PAT IOP values were 0.668 (p = 0.001) for G1, 0.463 (p = 0.002) for G2, 0.680 (p < 0.001) for G3, and 0.605 (p < 0.001) for G4. Moderate to good agreement between the two tonometers was found in all groups according to intraclass correlation coefficients, which were 0.794 (p < 0.001) for G1, 0.632 (p < 0.001) for G2, 0.809 (p < 0.001) for G3, and 0.740 (p < 0.001) for G4. The lower and upper limits of agreement between the devices were − 5.1 and 4.7 mmHg, respectively, in the complete group. No correlation was noted between CCT or AL and the Easyton® IOP measurements. Conclusion IOP measurements obtained with Easyton® and PAT show an acceptable level of agreement mainly in healthy individuals, recommending it for IOP screening in children and in patients in which PAT measurement may be impared as patients with hemifacial spasms, corneal irregularities, or reduced mobility. It is not recommended for glaucoma patients follow-up

Corneal aberrations in primary congenital glaucoma and its visual correlation

Received: 16 August 2022; Accepted: 11 April 2024; Published: 29 April 2024Primary congenital glaucoma (PCG) can cause permanent vision loss, and its prognosis is related to early detection and treatment. The main pathological defect consists of resistance to aqueous outflow through the trabecular meshwork due to abnormal development of tissue derived from the neural crest in the anterior chamber angle. Even after successful intraocular pressure (IOP) management in PCG poor visual outcomes still present a lifelong challenge. Vision loss in PCG is multifactorial, resulting from optic nerve damage, corneal scarring, and myopic astigmatism associated with anisometropic amblyopia. Although it is already known that children with PCG present with an altered corneal configuration, the knowledge of irregular astigmatism due to high-order aberrations (HOA) and due to the unequal expansion of the anterior segment, and its impact on visual outcomes, is not yet fully understood, to the best of our knowledge. Quality vision is influenced by the presence of aberrations in the eye's optical system, which can degrade the quality of the image projected onto the retina. Low-order aberrations (LOA), including myopia, hyperopia, and regular astigmatism, can be corrected by spectacles, while HOA cannot be corrected by ordinary means. Coma and spherical aberrations are the most visually significant HOAs, while trefoil and other HOAs have a lower impact on visual quality. The purpose of this article is to establish a quantitative correlation between HOA and visual acuity (VA) to measure the magnitude of the impact of the altered cornea on visual outcomes in PCG.Depto. de Inmunología, Oftalmología y ORLUnidad Docente de Inmunología, Oftalmología y ORLFac. de Óptica y OptometríaFac. de MedicinaTRUEpubPagado por el auto