Pig Eyes Research Articles

Operation behaviours of surgical forceps in continuous curvilinear capsulorhexis.

Continuous curvilinear capsulorhexis (CCC) is a delicate ophthalmic procedure which may benefit from robot technology. Measuring the behaviours (physiological tremor, operation force) of surgeons provides baseline data to develop assistive CCC robot. A forceps with fibre bragg grating and inertial sensors is used to measure the surgeons' behaviours while experts/novices perform CCC on ex-vivo pig eyes, in-vivo rabbit eyes and ex-vivo human lens. In pig/rabbit tests, the root-mean-square (RMS) tremor amplitude is 35.26/59.04μm (expert/novice, transverse), 13.3/20.55μm (axial). The RMS voluntary force (VF) and involuntary force (IF) are 8.97/17.16mN, and 0.66/1.90mN, respectively. In human lens test, the RMS tremor amplitude is 24.0μm (transverse, expert only), 9.88μm (axial). The RMS VF and RMS IF are 9.04mN (expert only) and 0.17mN, respectively. The expert surgeons have better precision and less operation force.

Scleral Cross-Linking in Form-Deprivation Myopic Guinea Pig Eyes Leads to Glaucomatous Changes.

PurposeTo investigate the potential glaucomatous changes caused by scleral cross-linking (CXL) in a guinea pig form-deprivation (FD) myopia model.MethodsEighty 4-week-old tricolor guinea pigs were divided into four groups: FD only, genipin CXL only, FD plus CXL, and control. Refractive error, axial length (AL), intraocular pressure (IOP), and structural and vasculature optic disc changes in optical coherence tomography (OCT) and OCT angiography (OCTA) were measured at baseline and day 21. CXL efficacy was evaluated by scleral rigidity Young's modulus values. Histological and molecular changes in the anterior chamber angle, retina, and sclera were assessed.ResultsBaseline parameters were similar among groups (P > 0.05). The FD plus CXL group at day 21 had the least increase of AL (0.14 ± 0.08 mm) and highest IOP elevation (31.5 ± 3.6 mmHg) compared with the FD-only group (AL: 0.68 ± 0.17 mm; IOP: 22.2 ± 2.6 mmHg) and the control group (AL: 0.24 ± 0.09 mm; IOP: 17.4 ± 1.8 mmHg) (all P < 0.001). OCT and OCTA parameters of the optic disc in the FD plus CXL group at day 21 showed glaucomatous changes and decreased blood flow signals. Sclera rigidity increased in the CXL and FD plus CXL groups. Advanced glycation end products deposited extensively in the retina, choroid, and sclera of FD plus CXL eyes.ConclusionsCXL causes increased IOP and subsequent optic disc, anterior segment, and scleral changes while inhibiting myopic progression and axial elongation in FD guinea pig eyes. Therefore, applying CXL to control myopia raises safety concerns.

Determining the learning curve for a novel microsurgical procedure using histopathology

PurposeWet laboratories are becoming an increasingly important training tool as part of a push to a proficiency-based training model. We created a microsurgical wet laboratory to investigate the utility of histopathology use in assessing surgical outcomes and determine the learning curve of a novel microsurgical procedure.MethodsA microsurgical wet laboratory was established using pig eyes to simulate the human cornea. Three novice surgeons and an experienced surgeon performed an anterior cornea lamellar dissection and the duration of the procedure was recorded. With the aid of histological analysis, the thickness and characteristics of the dissected graft was recorded. The number of attempts to complete the experiment, defined as three successful dissections with mean thickness below 100 μm, was documented.ResultsThe use of histopathology was highly successful allowing in-depth analysis of the dissected graft for each attempt. Trainees reached the endpoint of the study in 21, 26 and 36 attempts (mean: 28 attempts) whilst the corneal surgeon completed the experiment in 12 attempts (p = 0.07). Mean dissection thickness decreased over time for all participants. The mean dissection time for trainees was 10.6 ± 4.2 min compared to the corneal surgeon with a mean of 8.2 ± 3.1 min (p = 0.03).ConclusionWe propose a corneal wet laboratory model that allows for simple, efficient, and flexible microsurgical training. The use of histopathological analysis allows for careful graft analysis, providing objective feedback throughout the training exercise. Trainees demonstrated improvements in the three key aspects of the procedure: accuracy as evidenced by decreasing histological thickness, confidence by self-report and fluidity by decreasing duration of the procedure.

In vivo study to assess dosage of allogeneic pig retinal progenitor cells: Long-term survival, engraftment, differentiation and safety.

Despite notable efforts and significant therapeutical advances, age‐related macular degeneration remains the single most common reason for vision loss. Retinal progenitor cells (RPCs) are considered promising candidates for cellular treatments that repair and restore vision. In this allogenic study, the phenotypic profile of pig and human RPCs derived using similar manufacturing processes is compared. The long‐term (12‐week) survival of green fluorescent protein‐pig retinal progenitor cells GFP‐pRPC after subretinal transplantation into normal miniature pig (mini‐pig) retina is investigated. Human eyes are both anatomically and physiologically mimicked by pig eyes, so the pig is an ideal model to show an equivalent way of delivering cells, immunological response and dosage. The phenotypic equivalency of porcine and clinically intended human RPCs was established. Thirty‐nine mini‐pigs are used in this study, and vehicle‐injected eyes and non‐injected eyes serve as controls. Six groups are given different dosages of pRPCs, and the cells are found to survive well in all groups. At 12 weeks, strong evidence of integration is indicated by the location of the grafted cells within the neuro‐retina, extension of processes to the plexiform layers and expression of key retinal markers such as recoverin, rhodopsin and synaptophysin. No immunosuppression is used, and no immune response is found in any of the groups. No pRPC‐related histopathology findings are reported in the major organs investigated. An initial dose of 250 k cells in 100 µl of buffer is established as an appropriate initial dose for future human clinical trials.

Efficacy of scleral imbrication on all quadrants in enucleated pig eyes.

To evaluate the changes in axial length (AL) and corneal astigmatism induced by scleral imbrication on all quadrants in pig eyes. Experimental study METHODS: We produced scleral imbrications either on all quadrants or on 2 consecutive quadrants of 5 enucleated pig eyes. Scleral imbrications 8mm wide were made at 8mm from the limbus on each quadrant. We determined the AL using an electronic caliper and the corneal astigmatism using a keratometer before and after the 2 types of scleral imbrications and compared the changes in ocular AL and corneal astigmatism induced by the 2 surgical procedures. The AL reduction after the scleral imbrication on all quadrants (3.96 ± 0.56mm) was larger than that on 2 quadrants (2.39 ± 0.41mm) (P = .001). The change in corneal astigmatism induced by imbrication on all quadrants (2.98 ± 1.96 D) was less than that on 2 quadrants (5.95 ± 2.04 D) (P < .029). Scleral imbrication on all quadrants induced a shorter AL and less corneal astigmatism than did a standard scleral imbrication on 2 quadrants. Therefore, the former could be a more effective operation for retinal disorders associated with high myopia, including macular hole retinal detachment and myopic foveoschisis.

Воздействие лазера среднего инфракрасного диапазона на ткани глаза

Purpose. To study the effect of mid-infrared laser radiation on eye tissues. Material and methods. As a laser, an experimental laser device “Laser scalpel in the middle infrared range 2-8µm for precision surgery” developed at the Vavilov State Optical Institute. The experiment was carried out at a laser radiation wavelength of 3µm, which coincides with the peak of the spectral absorption of water. The retina, choroid, and sclera of pig eyes were used as biological tissue. The effect of laser radiation on tissue was carried out in air. The impact of laser radiation on eye tissues was assessed using an EVO LS10 scanning electron microscope from Zeiss (Germany). After obtaining an image on an electron microscope using the GNU Image Manipulation Program, the depth and diameter of the crater and the width of the collateral damage were calculated. Results and discussion. When exposed to a single laser pulse with an energy of 1 MJ, a through retinal defect was observed. With continuous exposure to laser radiation on the choroid with an energy from 1 to 3 MJ, the crater depth was 128–150 microns, the crater width was 87–110 microns, the collateral damage zone was 50–71 microns. With continuous exposure to laser radiation with similar parameters on the sclera, the depth of the crater, the width of the crater and the area of collateral damage were larger. Conclusions. The depth, width of the crater, the zone of collateral damage when exposed to laser radiation are directly proportional to the time, frequency and energy of the radiation. This laser can be useful in ophthalmic surgery, in particular in vitreoretinal surgery. However, further studies are needed to optimize the parameters of laser radiation. Keywords: vitrectomy, laser vitrectomy, photovitrectomy, Er:YAG laser, mid-infrared spectrum, laser ablation, precision surgery.

A Novel Tissue Identification Framework in Cataract Surgery Using an Integrated Bioimpedance-Based Probe and Machine Learning Algorithms.

The objective of this work was to develop and experimentally validate a bioimpedance-based framework to identify tissues in contact with the surgical instrument during cataract surgery. This work introduces an integrated hardware and software solution based on the unique bioimpedance of different intraocular tissues. The developed hardware can be readily integrated with commonly used surgical instruments. The proposed software framework, which encompasses data acquisition and a machine-learning classifier, is fast enough to be deployed in real-time surgical interventions. The experimental protocol included bioimpedance data collected from 31 ex vivo pig eyes targeting four intraocular tissues: Iris, Cornea, Lens, and Vitreous. A classifier based on a support vector machine exhibited an overall accuracy of 91% across all trials. The algorithm provided substantial performance in detecting the intraocular tissues with 100% reliability and 95% sensitivity for the lens, along with 88% reliability and 94% sensitivity for the vitreous. The developed impedance-based framework demonstrated successful intraocular tissue identification. Clinical implications include the ability to ensure safe operations by detecting posterior capsule rapture with 94% probability and improving surgical efficacy through lens detection with 100% reliability.

Establishment of a Xenograft Model of Human Retinoblastoma in Pig Eyes

Establishment of a Xenograft Model of Human Retinoblastoma in Pig Eyes

Decreased Choroidal Blood Perfusion Induces Myopia in Guinea Pigs.

PurposeThe development of myopia in guinea pigs can be inhibited by attenuating scleral hypoxia by increasing choroidal blood perfusion (ChBP). In this study, we reduced ChBP through surgical and pharmacological methods to determine the effect on myopia development. We also determined whether ChBP was reduced by quinpirole, a drug that enhances form-deprivation myopia (FDM).MethodsChBP was reduced in the right eyes of guinea pigs via transection of the temporal ciliary arteries or daily injections of phenylephrine into the inferior peribulbar space for one week during normal ocular growth. Other guinea pigs were subjected to two weeks of monocular FDM—with facemasks, along with daily injections of quinpirole, a dopamine D2 receptor agonist, to enhance the FDM. Changes in refraction, axial length, ChBP, and choroidal thickness (ChT) were measured in both treated and fellow eyes of the treatment and control groups. Scleral hypoxia labeling with pimonidazole adducts and α-smooth muscle actin (α-SMA) protein were also measured.ResultsSurgical and pharmacological reduction of ChBP induced myopia development in the treated eyes. These treatments rendered the scleral hypoxia and increased scleral α-SMA expression. Furthermore, quinpirole injections, which increased the magnitude of myopia, augmented the FDM-associated reductions in ChBP and ChT and increased the levels of scleral hypoxia and α-SMA protein.ConclusionsDecreased ChBP in guinea pigs leads to scleral hypoxia and scleral myofibroblast transdifferentiation with increased α-SMA expression, ultimately resulting in myopia development. In future clinical trials, ChBP reduction can serve as a potential biomarker for early detection of myopia development.

Using momentum to determine serious bodily injury: an experimental study using pig eyes

According to section 2 of the Criminal Code, a firearm is a barrelled weapon that can discharge a projectile capable of causing serious bodily injury or death to a person. Although not defined in the Criminal Code, serious bodily injury has been accepted in Canadian courts as the “penetration or rupture of an eye”. Classifying air guns may be difficult as they are usually not categorized as a firearm, but some are capable of meeting the criteria of a firearm. In previous studies, velocity and/or energy density were used to define a parameter V50, and a minimum energy density range where penetration may occur. This research project sought to evaluate the momentum of the projectile as a new parameter to determine if an air gun is capable of causing serious bodily injury. Three air guns, with five projectile types, were fired 10 times each into pig eyes. Results indicated that a minimum momentum value may be applied to each projectile of a different shape, regardless of the projectile’s mass. Minimum momentum values ranging from 0.026 kg*m/s (pointed) to 0.039 kg m/s (flat nose) were observed. It is hypothesised that impulse, which considers the cross-sectional area of projectiles, would be a universal parameter and more research should be done to test this.

Unilateral Corneal Insult Also Alters Sensory Nerve Activity in the Contralateral Eye.

After the unilateral inflammation or nerve lesion of the ocular surface, the ipsilateral corneal sensory nerve activity is activated and sensitized, evoking ocular discomfort, irritation, and pain referred to the affected eye. Nonetheless, some patients with unilateral ocular inflammation, infection, or surgery also reported discomfort and pain in the contralateral eye. We explored the possibility that such altered sensations in the non-affected eye are due to the changes in their corneal sensory nerve activity in the contralateral, not directly affected eye. To test that hypothesis, we recorded the impulse activity of the corneal mechano- and polymodal nociceptor and cold thermoreceptor nerve terminals in both eyes of guinea pigs, subjected unilaterally to three different experimental conditions (UV-induced photokeratitis, microkeratome corneal surgery, and chronic tear deficiency caused by removal of the main lacrimal gland), and in eyes of naïve animals ex vivo. Overall, after unilateral eye damage, the corneal sensory nerve activity appeared to be also altered in the contralateral eye. Compared with the naïve guinea pigs, animals with unilateral UV-induced mild corneal inflammation, showed on both eyes an inhibition of the spontaneous and stimulus-evoked activity of cold thermoreceptors, and increased activity in nociceptors affecting both the ipsilateral and the contralateral eye. Unilateral microkeratome surgery affected the activity of nociceptors mostly, inducing sensitization in both eyes. The removal of the main lacrimal gland reduced tear volume and increased the cold thermoreceptor activity in both eyes. This is the first direct demonstration that unilateral corneal nerve lesion, especially ocular surface inflammation, functionally affects the activity of the different types of corneal sensory nerves in both the ipsilateral and contralateral eyes. The mechanisms underlying the contralateral affectation of sensory nerves remain to be determined, although available data support the involvement of neuroimmune interactions. The parallel alteration of nerve activity in contralateral eyes has two main implications: a) in the experimental design of both preclinical and clinical studies, where the contralateral eyes cannot be considered as a control; and, b) in the clinical practice, where clinicians must consider the convenience of treating both eyes of patients with unilateral ocular conditions to avoid pain and secondary undesirable effects in the fellow eye.

Dynamic Changes of AREG in the Sclera during the Development of Form-Deprivation Myopia in Guinea Pigs

ABSTRACTPurposeTo investigate amphiregulin (AREG) expression in the sclera during the development of form-deprivation myopia (FDM) and after the recovery of FDM in guinea pigs.MethodsSixty-four 2-week-old guinea pigs were randomly divided into the control and FDM groups. The right eyes of animals in FDM group were covered for 2 weeks (2 W) and 4 weeks (4 W), or were covered for 4 weeks and then uncovered for the subsequent 2 weeks (6 W). The diopters and axial lengths (AL) in the right eyes of guinea pigs were measured. Reverse transcription polymerase chain reaction (RT-PCR), immunofluorescence, and western blotting assays were used to detect the relative mRNA and protein expressions of AREG in the sclera of guinea pigs.ResultsBefore masking (0 W), the refraction and AL in the right eyes of guinea pigs in the control and FDM groups did not differ significantly (both p > .05). Myopic shift was induced in guinea pigs with the diopters gradually decreased and AL increased in the FDM group. While no significant difference was found in control group at different time points, the relative AREG mRNA and protein expression levels in the FDM group were significantly increased in 2 W and 4 W and then decreased after 4 weeks of covering followed by uncovering for 2 weeks (all p < .05).ConclusionsAREG was expressed in the sclera of guinea pigs. Moreover, the expression levels of AREG increased during the development of FDM and downregulated after recovery of FDM. Therefore, AREG may be involved in the regulation of scleral remodeling in myopia.

Comparison of 3D Digitally Assisted Visualization System with Current Standard Visualization for the Removal of Vitreous in a Preclinical Model.

PurposeNovel 3D digital display systems, such as NGENUITY 3D digitally assisted visualization system (DAVS), can provide enhanced illumination, depth of field, and digital filtering. This study compared vitreous removal using NGENUITY 3D DAVS with a standard surgical microscope.MethodsThis was an in vivo, 2-arm laboratory study in 15 Yorkshire pig eyes. The LuxOR LX3 microscope with NGENUITY 3D DAVS (arm 1) and the LuxOR LX3 microscope alone (arm 2) were used with 5× optical magnification and Oculus BIOM 200 mm optics. Standard core and peripheral vitrectomy without scleral depression was performed using the CONSTELLATION Vision System. Residual vitreous weight was assessed in enucleated eyes by a masked observer. Axial length and vitreous weight of contralateral eyes were compared from an additional 14 Yorkshire pigs to confirm that eyes from a single animal were essentially identical.ResultsAfter vitrectomy, mean ± SD residual vitreous was significantly smaller with NGENUITY versus standard microscope (0.143 ± 0.146 versus 0.580 ± 0.269 g, respectively; P < 0.0001). Based on a mean initial vitreous weight of 2.5 g, as determined by assessment in contralateral eyes from an additional 14 Yorkshire pigs, the mean percentage vitreous removal was 94% ± 6% versus 77% ± 11%, respectively. Further, vitreous weight and axial length for contralateral eyes from any single animal in these additional 14 animals were essentially identical, as mean differences were 0.046 ± 0.035 g and 0.11 ± 0.08 mm, respectively.ConclusionVitrectomy with NGENUITY 3D DAVS resulted in significantly less residual vitreous in pig eyes compared with standard microscopy. NGENUITY may improve vitreous removal during vitreoretinal surgery by enhancing visualization.

High-frequency quantitative ultrasound to assess chemical crosslinking induced changes in the posterior sclera

Myopia alters the collagen microstructure of the sclera which changes the tissue biomechanical properties. Although most forms of myopia are mild, progression of the disease to high or pathologic myopia can lead to significant weakening of the sclera and greatly increase the risk for the formation of a posterior staphyloma, a sight-threatening condition. Potential treatments to counteract effects of myopia on the sclera include chemical crosslinking (CXL). Formaldehyde releasing agents like sodium hydroxymethylglycinate (SHMG) are an attractive option for the posterior sclera because they increase tissue stiffness and require no light activation. Previous research has demonstrated that high-frequency quantitative ultrasound (QUS) is sensitive to the microstructural changes in the sclera caused by myopia. In this study, we investigate the ability of QUS to monitor microstructural changes caused by CXL. Ex vivo pig eyes were immersed in a 26.5 mM SHMG solution and scanned by an 80MHz ultrasound transducer at regular time intervals. RF echo data were analyzed to compute QUS parameters from the backscatter coefficient, normalized power spectrum, and echo envelope statistics. Correlations between QUS parameters and immersion time were investigated to evaluate the efficacy of QUS for monitoring CXL treatment. Results of this study demonstrate the capability to high-frequency QUS to assess changes in tissue microstructure caused by CXL with SHMG.

Usability of abattoir-acquired pig eyes for refractive excimer laser research

The purpose of this study was to elucidate, under which conditions abattoir-acquired pig eyes are suitable for refractive excimer laser experiments. Porcine eyes from tunnel-scalded (n = 5) and tank-scalded (n = 10) pigs were compared to unscalded eyes (n = 5) and to eyes scalded in the laboratory (n = 5). The corneal epithelium was removed before an excimer laser was used to perform a − 8.0 D photoablation. Corneal thickness was measured by optical coherence topography before and after photoablation. The ablation depth was determined with a contour measuring station, the morphology of the ablated areas was characterized by scanning electron microscopy and white-light profilometry. The scalded eyes showed an increase in corneal swelling which gained statistical significance in tank-scalded eyes showing a wedge-shaped opaque stromal lesion in the nasal corneal quadrant. A measurable deterioration of photoablation was only found in tank-scalded eyes that exhibited the opaque lesion. Ablated area morphology was smooth and regular in the unscalded and tunnel-scalded eyes. The tank-scalded eyes showed conspicuous wrinkles. While unscalded eyes should always be preferred for excimer laser laboratory experiments, the data suggest that the use of tunnel-scalded eyes may also be acceptable and should be chosen over tank-scalded eyes.

Oral immunization of Escherichia albertii strain DM104 induces protective immunity against Shigella dysenteriae type 4 in mouse model.

The recent rise of antibiotic resistance and lack of an effective vaccine make the scenario of shigellosis alarming in developing countries like Bangladesh. In recent years, our group reported the vaccine efficacy of a non-pathogenic Escherichia albertii strain DM104 in different animal models, where an ocularly administered vaccine in the guinea pig eye model against Shigella dysenteriae type 4 challenge showed high protective efficacy and also induced a high titer of serum IgG against S. dysenteriae type 4 whole cell lysate (WCL) and LPS. In this study, we report further evaluation of the non-invasive and non-toxic environmental strain DM104 as a vaccine candidate against S. dysenteriae type 4 in mice model. Oral immunization of live DM104 bacterial strain demonstrated better protective immunity in mice model by showing 90% protection in mice against live S. dysenteriae type 4 lethal dose challenge and by inducing effective humoral and mucosal immune responses.

Semi-Automated Extraction of Lens Fragments via a Surgical Robot Using Semantic Segmentation of OCT Images with Deep Learning - Experimental Results in ex vivo Animal Model.

The overarching goal of this work is to demonstrate the feasibility of using optical coherence tomography (OCT) to guide a robotic system to extract lens fragments from ex vivo pig eyes. A convolutional neural network (CNN) was developed to semantically segment four intraocular structures (lens material, capsule, cornea, and iris) from OCT images. The neural network was trained on images from ten pig eyes, validated on images from eight different eyes, and tested on images from another ten eyes. This segmentation algorithm was incorporated into the Intraocular Robotic Interventional Surgical System (IRISS) to realize semi-automated detection and extraction of lens material. To demonstrate the system, the semi-automated detection and extraction task was performed on seven separate ex vivo pig eyes. The developed neural network exhibited 78.20% for the validation set and 83.89% for the test set in mean intersection over union metrics. Successful implementation and efficacy of the developed method were confirmed by comparing the preoperative and postoperative OCT volume scans from the seven experiments.

Quantitative proteomic analysis of scleras in guinea pig exposed to wavelength defocus

Myopia is the most common optical disorder in the world, and wavelength defocus induced ametropia and myopia have attracted great attention. The objective was to identify and quantify scleral proteins involved in the response to the wavelength defocus. Guinea pigs were randomly divided into 3 groups that received different lighting conditions for 8 weeks: white light, short wavelength light, and long wavelength light. Refraction and axial length were measured, Hematoxylin-Eosin staining and transmission electron microscope were adopted to observe the scleral structure, and scleral proteome was also detected to analyze protein abundance by employing TMT labeling method. After light stimulation, the long- and short -wavelength light induced myopic and hyperopic effect on the guinea pig's eye and induced distinct protein signature, respectively. 186 dyregulated proteins between the short- and long-wavelength group were identified, which were mainly located in extracellular region and involved in metabolic process. We also found that 5 proteins in the guinea pigs scleras in response to wavelength defocus were also human myopic candidate targets, suggesting functional overlap between dyregulated proteins in scleral upon exposure to wavelength defocus and genes causing myopia in humans. SignificanceWavelength defocus induces refractive errors and leads to myopia or hyperopia. However, sclera proteomics respond to wavelength defocus is lacking, which is crucial to understanding how wavelength defocus influences refractive development and induces myopia. In this proteome analysis, we identified unique protein signatures response to wavelength defocus in sclera of guinea pigs, identified potential mechanisms contributing to myopia formation, and found that several human myopia-related genes may involve in response to wavelength defocus. The results of this study provide a foundation to understand the mechanisms of myopia and wavelength defocus induced ametropia.

Newly Identified Chemicals Preserve Mitochondrial Capacity and Decelerate Loss of Photoreceptor Cells in Murine Retinal Degeneration Models.

Purpose: Metabolic stress and associated mitochondrial dysfunction are implicated in retinal degeneration irrespective of the underlying cause. We identified seven unique chemicals from a Chembridge DiverSET screen and tested their protection against photoreceptor cell death in cell- and animal-based approaches. Methods: Calcium overload (A23187) was triggered in 661W murine photoreceptor-derived cells, and changes in redox potential and real-time changes in cellular metabolism were assessed using the MTT and Seahorse Biosciences XF assay, respectively. Cheminformatics to compare structures, and biodistribution in the living pig eye aided in selection of the lead compound. In-situ, retinal organ cultures of rd1 mouse and S334ter-line-3 rat were tested, in-vivo the light-induced retinal degeneration in albino Balb/c mice was used, assessing photoreceptor cell numbers histologically. Results: Of the seven chemicals, six were protective against A23187- and IBMX-induced loss of mitochondrial capacity, as measured by viability and respirometry in 661W cells. Cheminformatic analyses identified a unique pharmacophore with 6 physico-chemical features based on two compounds (CB11 and CB12). The protective efficacy of CB11 was further shown by reducing photoreceptor cell loss in retinal explants from two retinitis pigmentosa rodent models. Using eye drops, CB11 targeting to the pig retina was confirmed. The same eye drops decreased photoreceptor cell loss in light-stressed Balb/c mice. Conclusions: New chemicals were identified that protect from mitochondrial damage and lead to improved mitochondrial function. Using ex-vivo and in-vivo models, CB11 decreased the loss of photoreceptor cells in murine models of retinal degeneration and may be effective as treatment for different retinal dystrophies.

Goldmann Tonometry and Corneal Biomechanics

Glaucoma is the second cause of irreversible blindness in the world. Intraocular pressure (IOP) is a recognized major risk factor for the development and progression of glaucomatous damage. Goldmann applanation tonometry (GAT) is internationally accepted as the gold standard for the measurement of IOP. The purpose of this study was to search for correlations between Goldmann tonometry and corneal mechanical properties and thickness by means of in vitro tests. IOP was measured by the Goldmann applanation tonometer (GIOP), and by a pressure transducer inserted in the anterior chamber of the eye (TIOP), at increasing pressure levels by addition of saline solution in the anterior chamber of enucleated pig eyes (n = 49). Mechanical properties were also determined by inflation tests. The GAT underestimated the real measurements made by the pressure transducer, with most common differences in the range 15–28 mmHg. The difference between the two instruments, highlighted by the Bland–Altman test, was confirmed by ANOVA, normality tests, and Mann–Whitney’s tests, both on the data arranged for infusions and for the data organized by pressure ranges. Pearson correlation tests revealed a negative correlation between (TIOP-GIOP) and both corneal stiffness and corneal thickness. In conclusion, data obtained showed a discrepancy between GIOP and TIOP more evident for softer and thinner corneas, that is very important for glaucoma detection.