The large Hellenic Study of Uveitis: epidemiology, etiologic factors and classification.

PURPOSE: To analyse the demography, etiology, and classification of uveitis at a tertiary academic referral center. METHODS: An observational study was conducted on the archives of uveitic patients at the Ocular Inflammation Service of the Department of Ophthalmology at the University Hospital of Ioannina (Greece) from 1991 to 2020. This study aimed to investigate the epidemiological profile of patients, including their demographics and the main etiologic factors of uveitis. RESULTS: Out of 6191 cases with uveitis, 1925 were infectious, 4125 were non-infectious, and an overall of 141 masquerade syndromes were recorded. Among these cases, 5950 patients were adults, with a slight female predominance, while 241 were children (< 18 years old). Interestingly, 24.2% of cases (1500 patients) were associated with 4 specific microorganisms. Herpetic uveitis (HSV-1 and VZV/HZV) was the most common cause of infectious uveitis (14.87%), followed by toxoplasmosis (6.6%) and tuberculosis (2.74%). In 49.2% of non-infectious uveitis cases, no systematic correlation was found. The most frequent causes of non-infectious uveitis included sarcoidosis, white dot syndromes, ankylosing spondylitis, lens-induced uveitis, Adamantiades-Behçet disease, and idiopathic juvenile arthritis. Infectious uveitis was more common in the rural population, whereas non-infectious uveitis was more frequently recorded in the urban population CONCLUSIONS: Although our study was conducted on a predominantly white Caucasian population, it also reflects the effect of increasing immigration, improvements of diagnostic techniques, changes in referral patterns, and various actual changes in disease incidence.

Evaluation of the choriocapillaris after photodynamic therapy for chronic central serous chorioretinopathy. A review of optical coherence tomography angiography (OCT-A) studies.

PURPOSE: Emerging evidence suggests that choroidal microcirculation and microstructural changes after verteporfin photodynamic therapy (vPDT) for chronic central serous chorioretinopathy (CSC) can be shown in detail using OCT-Angiography (OCT-A). The use of OCT-A for the examination of choriocapillaris (CC) has attracted significant attention as the technique offers potential explanations for the effects of vPDT on choroidal tissue. METHODS: A meticulous literature search was performed in the PubMed database without restriction on year of publication until June 2021. The reference list of all electronically retrieved articles was carefully reviewed for potentially relevant articles that had not been identified. RESULTS: We identified and reviewed 11 studies reporting a comprehensive update on microvasculature and morphologic changes of the CC layer as seen on OCT-A in chronic CSC. The reviewed articles extensively analyze both the qualitative and quantitative characteristics of the CC flow pattern after applying vPDT safety-enhanced protocols. The changes in the CC plexus indicate the potential of beneficial or deleterious treatment effect on choroidal tissue remodeling. The reviewed series have revealed variability of flow pattern, vessel density, and perfusion of the CC over time. CONCLUSION: The CC plexus alterations during the post-vPDT period in chronic CSC may imply the treatment effect on choroidal tissue, indicating the potential of anatomical or functional recovery over time. The reviewed literature may confirm the diagnostic value of OCT-A in the assessment of the pathophysiology of eyes with CSC.

The Effect of Diabetes Mellitus on Corneal Endothelial Cells and Central Corneal Thickness: A Case-Control Study.

PURPOSE: The aim of this study was to evaluate the characteristics of corneal endothelial cells and central corneal thickness (CCT) in patients with diabetes mellitus (DM), comparing them with those of healthy subjects (controls) and to determine potential factors affecting the corneal parameters in patients with DM. METHODS: Participants in this study were 72 patients with DM and 88 healthy controls. Diabetic patients were further classified into groups depending on the severity of diabetic retinopathy (no retinopathy, mild, moderate, severe non-proliferative diabetic retinopathy, and proliferative diabetic retinopathy). All participants underwent non-contact specular microscopy to evaluate corneal endothelium parameters and CCT, while factors affecting endothelial cell density and CCT in patients with DM were also analyzed. RESULTS: Patients with DM presented significantly decreased endothelial cell density compared to controls (2,297.9 ± 311.3 and 2,518.3 ± 243.7 cells/mm2, respectively; p < 0.001), while the two groups did not differ significantly in any other measured corneal parameter. In the diabetic group, the multivariate analysis showed a significant association between decreased endothelial cell density and increased HbA1c (p < 0.001), longer DM duration (p = 0.003), and more severe diabetic retinopathy status (p = 0.008). CONCLUSION: DM seems to affect the corneal endothelium, since endothelial cell density was decreased in the diabetic group, while duration of disease, HbA1c levels, and severity of retinopathy were significantly associated with changes in endothelial cell density and should be taken into account.

Validation of Fourier analysis of videokeratographic data.

PURPOSE: The aim was to assess the repeatability of Fourier transfom analysis of videokeratographic data using Pentacam in normal (CG), keratoconic (KC) and post-CXL (CXL) corneas. METHODS: This was a prospective, clinic-based, observational study. One randomly selected eye from all study participants was included in the analysis: 62 normal eyes (CG group), 33 keratoconus eyes (KC group), while 34 eyes, which had already received CXL treatment, formed the CXL group. Fourier analysis of keratometric data were obtained using Pentacam, by two different operators within each of two sessions. Precision, repeatability and Intraclass Correlation Coefficient (ICC), were calculated for evaluating intrassesion and intersession repeatability for the following parameters: Spherical Component (SphRmin, SphEcc), Maximum Decentration (Max Dec), Regular Astigmatism, and Irregularitiy (Irr). Bland-Altman analysis was used for assessing interobserver repeatability. RESULTS: All parameters were presented to be repeatable, reliable and reproductible in all groups. Best intrasession and intersession repeatability and reliability were detected for parameters SphRmin, SphEcc and Max Dec parameters for both operators using ICC (intrasession: ICC > 98%, intersession: ICC > 94.7%) and within subject standard deviation. Best precision and lowest range of agreement was found for the SphRmin parameter (CG: 0.05, KC: 0.16, and CXL: 0.2) in all groups, while the lowest repeatability, reliability and reproducibility was detected for the Irr parameter. CONCLUSIONS: The Pentacam system provides accurate measurements of Fourier tranform keratometric data. A single Pentacam scan will be sufficient for most clinical applications.

Fourier analysis algorithm for the posterior corneal keratometric data: clinical usefulness in keratoconus.

PURPOSE: To develop an algorithm for the Fourier analysis of posterior corneal videokeratographic data and to evaluate the derived parameters in the diagnosis of Subclinical Keratoconus (SKC) and Keratoconus (KC). METHODS: This was a cross-sectional, observational study that took place in the Eye Institute of Thrace, Democritus University, Greece. Eighty eyes formed the KC group, 55 eyes formed the SKC group while 50 normal eyes populated the control group. A self-developed algorithm in visual basic for Microsoft Excel performed a Fourier series harmonic analysis for the posterior corneal sagittal curvature data. The algorithm decomposed the obtained curvatures into a spherical component, regular astigmatism, asymmetry and higher order irregularities for averaged central 4 mm and for each individual ring separately (1, 2, 3 and 4 mm). The obtained values were evaluated for their diagnostic capacity using receiver operating curves (ROC). Logistic regression was attempted for the identification of a combined diagnostic model. RESULTS: Significant differences were detected in regular astigmatism, asymmetry and higher order irregularities among groups. For the SKC group, the parameters with high diagnostic ability (AUC > 90%) were the higher order irregularities, the asymmetry and the regular astigmatism, mainly in the corneal periphery. Higher predictive accuracy was identified using diagnostic models that combined the asymmetry, regular astigmatism and higher order irregularities in averaged 3and 4 mm area (AUC: 98.4%, Sensitivity: 91.7% and Specificity:100%). CONCLUSIONS: Fourier decomposition of posterior Keratometric data provides parameters with high accuracy in differentiating SKC from normal corneas and should be included in the prompt diagnosis of KC.

Effect of Riboflavin/UVA Collagen Cross-linking on Central Cornea, Limbus and Intraocular Pressure. Experimental Study in Rabbit Eyes.

The Purpose of present study was to investigate the effect of riboflavin/ultraviolet-A-induced collagen cross-linking (CXL) on central cornea, limbus and intraocular pressure (IOP). This was an animal experimental study. The right corneas of 10 rabbits were ultraviolet-A irradiated (3 mW/cm2 for 30 minutes) after de-epithelialization and instillation of 0.1% riboflavin / 20% Dextran drops. Left corneas served as controls. Samples were examined histologically one month postoperatively. Before and after treatment, IOP measurements were recorded bilaterally. At central cornea of eyes underwent CXL keratocyte repopulation, normal arrangement of collagen fibres and a statistically significant change in fibres diameter were detected, compared to controls. At limbus area, there were not any significant histological differences after CXL. There was no statistically significant difference between pre- and postoperative IOP in all eyes.

Contribution of reference bodies in diagnosis of keratoconus.

PURPOSE: To evaluate the contribution of reference bodies for elevation maps in diagnosis of keratoconus (KC) and forme fruste keratoconus (FFK). METHODS: Study groups included (1) 80 eyes with KC, (2) 55 eyes with FFK, and (3) 95 eyes as control eyes. The maximum elevation value at the central 5 mm of the posterior cornea (MEL) and the elevation value at thinnest corneal point (TEL) were evaluated for their diagnostic capacity using receiver operating characteristic curves under the following reference bodies: sphere, ellipsoid, toric ellipsoid, and torus, with autodiameter and fixed 8-mm-diameter settings. Moreover, characteristic parameters for each reference body and the root mean square (RMS) were evaluated for their diagnostic capacity. RESULTS: Significant differences were detected in TEL, MEL, and RMS parameters among groups, for almost all reference bodies. The highest predictive accuracy (KC group, >99.97%; FFK group, >90.9%) was estimated for the TEL and MEL parameters using the toric ellipsoid (8 mm) reference body with a fixed eccentricity of 0.4. Moreover, the RMS parameter demonstrated sufficient diagnostic capacity (KC group, 99.95%; FFK group, 85.1%). The cutoff points for the TEL parameter were found to be 7 and 3 µm in the KC group and the FFK group, respectively; for the MEL parameter, they were 11 and 6 µm, respectively; and for the RMS parameter, they were 6.87 and 7.19 µm, respectively. CONCLUSIONS: The posterior corneal elevation values and the RMS parameter can effectively discriminate KC from normal corneas, although measured values and cutoff points depend on the selection of reference body. Moreover, the use of a toric ellipsoid reference body, with a fixed eccentricity of 0.4, seems to be an effective tool even in diagnosis of FFK.

Early recurrence of macular schisis in X-linked retinoschisis treated with vitrectomy for rhegmatogenous retinal detachment under silicone oil: case report and brief literature review.

X-linked retinoschisis (XLRS) is an inherited retinal degeneration affecting males, characterized by splitting of the retinal layers. We herein present the outcomes of surgical treatment in a case of XLRS complicated by rhegmatogenous retinal detachment (RRD). A 22-year-old male presented to the emergency department due to decreased visual acuity and visual field defect in his left eye Oculus Sinister (OS) of 1 week duration. The patient reported an early onset retinal degeneration and decreased visual acuity in both eyes since childhood in his past ocular history. Upon presentation, best corrected visual acuity (BCVA) was 6/30 on the right eye Oculus Dexter (OD) and 6/120 OS. Fundus examination revealed areas of peripheral retinal schisis, and the characteristic spoke wheel pattern on the macula of both eyes. In OS, a temporal RRD involving the macula was identified. The patient underwent surgical treatment with pars plana vitrectomy with internal limiting membrane (ILM) peeling, endolaser, and silicone oil (SO) tamponade. BCVA in OS improved to 6/60 and schistic cavities resolution was observed in the immediate postoperative period. The patient's BCVA further improved to 6/19 at 1 month, as foveal anatomy showed relative improvement. However, there was a rapid reappearance of schisis spaces in the macular area at this point, which was also followed by progressive deterioration of foveal schisis by 3 months post-operatively. The resorption and recurrence of lamellar macular schisis changes after ILM peel and presence of SO, highlights that although XLRS findings can temporarily improve upon surgical intervention, the pathogenetic mechanisms contributing to disease phenotype remain to be elucidated.

Retinal capillary plexus in Parkinson's disease using optical coherence tomography angiography.

AIM: To evaluate the alterations of the retinal microvasculature and foveal avascular zone in patients with Parkinson's disease (PD) using optical coherence tomography angiography (OCT-A). METHODS: A retrospective study of PD patients examined in the Ophthalmology Department of the General Hospital of Athens, "Georgios Gennimatas" from March 2021 to March 2022 was conducted. Totally 44 patients with PD were included and 18 healthy controls were examined, hence a total of 124 eyes were enrolled in the study. The foveal and parafoveal superficial and deep capillary plexus vascular density (fSCP-VD, fDCP-VD, pSCP-VD, pDCP-CD) and foveal avascular zone (FAZ) were quantified with OCTA. Optical coherence tomography (OCT) was used to measure macular thickness. Our statistical analysis was conducted by using a mixed effect linear regression model. RESULTS: After adjustment for age and gender, the mean parafoveal superficial capillary plexus vascular density (pSCP-VD) and mean parafoveal deep capillary plexus vascular density (pDCP-VD) were significantly decreased in individuals with PD (P<0.001 in both) by -2.35 (95%CI -3.3, -1.45) and -7.5 (95%CI -10.4, -4.6) respectively. fSCP-VD and fDCP-VD didn't approach statistical significance. The FAZ area and perimeter were significantly decreased (P<0.001 in both) by -0.1 mm2 (95%CI -0.13, -0.07) and -0.49 mm2 (95%CI -0.66, -0.32) respectively. Circularity didn't approach statistical significance. Central retinal thickness (CRT) was significantly decreased in individuals with PD (P<0.001) by -23.1 µm (95%CI -30.2, -16) and temporal retinal thickness (TRT) was decreased (P=0.025) by -11 µm (95%CI -22, -1.5) while nasal retinal thickness (NRT) only approached statistical significance (P=0.066). CONCLUSION: The mean pSCP-VD, pDCP-VD, CRT and TRT are significantly decreased and FAZ is altered in individuals with PD. These findings can be potentially used as biomarkers for the diagnosis and evaluation of early PD.

Biodegradable nanoparticles for controlled subconjunctival delivery of latanoprost acid: in vitro and in vivo evaluation. Preliminary results.

Purpose of the study was to develop and assess a novel controlled drug delivery system of latanoprost acid (LA). Poly(lactide)/Monomethoxy-poly(ethyleneglycol) (PLA-PEG) nanoparticles (NPs) were prepared using an emulsification-solvent evaporation technique. NPs were characterized in vitro according to their size, ζ-potential, drug entrapment efficiency and LA release. LA-loaded NPs (equivalent to 8.5 µg LA) were administered into the subconjunctival space of normotensive rabbits (group A). A free LA solution of the same drug content was subconjunctivally injected in a second rabbit group (group B), while blank NPs were administered in a third group (group C). A group of untreated animals (group D) served as the control. Intraocular pressure (IOP) was monitored for 8 consecutive days, using the Tono-pen XL. Aqueous humor (AH) levels of LA were evaluated for 6 days post-administration, by means of HPLC. Mean nanoparticle size was 80 nm. The drug entrapment efficiency was 18.3%. NPs sustained the release of LA over several days in vitro. Non-significant differences in baseline IOP were found between groups (p = 0.22). LA-loaded NPs exerted a significant hypotensive effect on group A, while IOP values remained significantly lower compared to the rest groups, throughout the study (p = 0.04). LA AH concentrations in group B continuously decreased with time, while LA levels in group A steadily increased. On day 6, LA levels were higher in group A compared to group B (344 ± 73.5 ng/ml and 228 ± 41.01 ng/ml, respectively). No adverse effects were observed. In conclusion, after subconjunctival administration, the LA-loaded NPs provided sustained LA delivery in vivo. They appear to be a promising system for the controlled subconjunctival delivery of LA.

Tissue inhibitor of metalloproteinase 4 in aqueous humor of patients with primary open angle glaucoma, pseudoexfoliation syndrome and pseudoexfoliative glaucoma and its role in proteolysis imbalance.

BACKGROUND: To quantify the levels of tissue inhibitor of metalloproteinase 4 (TIMP4) and its ratios with free metalloproteinases (MMP) in the aqueous humor of patients with primary open angle glaucoma (POAG), pseudoexfoliation syndrome (PXS) and pseudoexfoliative glaucoma (PXG) and to evaluate a possible imbalance between MMPs and TIMPs in these samples. METHODS: Free MMP2, MMP3, MMP9, TIMP1, TIMP2, TIMP4 concentrations and active levels of MMP2 and MMP3 were determined with immunoassay ELISA and activity assay kits in 168 aqueous samples. RESULTS: TIMP4 was elevated in glaucoma patients(POAG: 0.95 ± 0.49 PXG: 1.28 ± 1.38 pg/ml. p < 0.001). POAG, PXS and PXG samples demonstrated higher MMP2, TIMP1 and TIMP2 concentrations (p < 0.001). Samples from the PXS and PXG groups had a lower total/active MMP2 ratio (p < 0.004 and p < 0.008 respectively). Stoichiometric analysis showed an overbalance of TIMPsover MMPs in both POAG & PXG groups,especially of TIMP4. CONCLUSION: TIMP4 elevation is a novel finding in glaucomatous eyes. A disregulation of extracellular matrix homeostasis is suggested in POAG, PXS and PXG.

Liquefaction versus torsional IP: a comparative study on endothelial cells, corneal edema and corneal sensitivity.

BACKGROUND/AIMS: To compare the impact of liquefaction and torsional IP cataract extraction methods on endothelial cell count (ECC), central corneal edema, and central corneal sensitivity (CCS) in a sample of cataract patients. METHODS: The liquefaction (LG) and torsional IP (TG) group consisted of 47 and 48 grade 2 cataract eyes, respectively. Uncorrected and best spectacle-corrected visual acuity, ECC, central corneal thickness (CCT), and CCS were measured 1 day prior to surgery, 10 days, 1 and 3 months postoperatively. RESULTS: Significant difficulties in the nucleus fragmentation were encountered in 2 LG eyes, and they were excluded from the study. Both techniques provided excellent refractive outcomes (LG, p < 0.001; TG, p = 0.02). Nonsignificant differences were detected in CCT values at the final postoperative examination; however, TG patients presented higher CCT on the first postoperative day (p = 0.04). Both groups presented comparable significant reductions in ECC (LG, p < 0.001; TG, p < 0.001) and CCS (LG, p = 0.02; TG, p = 0.02). CONCLUSION: Both methods provide excellent refractive outcomes, with comparable impact on ECC and CCS. Liquefaction seems to provide less corneal edema; however, difficulties in nucleus fragmentation may be encountered even in grade 2 cataracts.

Late PAMM-Like Lesions in a Patient with HIV Retinopathy.

This report describes a case of a newly diagnosed 49-year-old HIV patient, who presented with decreased visual acuity and retinal lesions characterized by ischemia at the level of the deep retinal capillary plexus, documented with optical coherence tomography (OCT), OCT angiography, fluorescein angiography, and visual fields testing. These lesions closely resembled the morphologic and clinical characteristics of late paracentral acute middle maculopathy. The presence of these lesions suggests that HIV microangiopathy can potentially affect both superficial and deep retinal capillary plexuses.

Macular Edema Following Silicone Oil Tamponade for Retinal Detachment: A Literature Review.

Macular edema (ME) is a major cause of reduced vision following intraocular surgery. Although the pathophysiology of ME is not completely understood, inflammatory mediators play a key role. The incidence of ME following pars plana vitrectomy with silicone oil tamponade varies between 13% and 27%. ME usually resolves spontaneously following silicone oil removal, but treatment may be required for resistant cases. In this review, the mechanisms of ME formation after pars plana vitrectomy, its incidence, and its possible therapeutic approaches are discussed.

Impact of flight and equivalent short-term high-altitude exposure on ocular structures and function.

Background: Exposure to high-altitude conditions during flight or similar activities affects many aspects of visual function, which is critical not only for flight safety but for any altitude-related activity. We aimed to summarize the available literature pertaining to ocular changes during flight or equivalent short-term high-altitude exposure (e.g., hypobaric chamber, effortless ascent lasting ≤ 24 h) and to highlight future research priorities. Methods: Using the PubMed/MEDLINE and Web of Science/ISI Web of Knowledge databases with structured search syntax, we conducted a systematic review of the literature spanning a 40-year period (January 1, 1983, to October 10, 2023). Articles pertaining to ocular changes during flight or flight-equivalent exposure to altitude were retrieved. The reference lists of retrieved studies were also searched, and citations of these references were included in the results. Results: Of 875 relevant PubMed and ISI publications, 122 qualified for inclusion and 20 more were retrieved from the reference lists of initially selected records, for a total of 142 articles. Reported anterior segment changes included deterioration in tear film stability and increased dry eye incidence, increased corneal thickness, discomfort and bubble formation in contact lens users, refraction changes in individuals with prior refractive surgery, decreased intraocular pressure, and alterations in pupillary reaction, contrast sensitivity, and visual fields. Photoreceptor-visual pathway changes included alterations in both photoreceptors and neuro-transduction, as evidenced in dark adaptation, macular recovery time, reduction in visual field sensitivity, and optic neuritis (likely an element of decompression sickness). Retinochoroidal changes included increases in retinal vessel caliber, retinal blood flow, and choroidal thickness; central serous chorioretinopathy; and retinal vascular events (non-arteritic ischemic optic neuropathy, high-altitude retinopathy, and retinal vein occlusion). Conclusions: The effect of short-term high-altitude exposure on the eye is, in itself, a difficult area to study. Although serious impairment of visual acuity appears to be rare, ocular changes, including tear film stability, contact lens wear, central corneal thickness, intraocular pressure, contrast sensitivity, stability of refractive surgeries, retinal vessels, visual fields, and macula recovery time, should be considered in civilian aviators. Our report provides guidance to climbers and lowlanders traveling to altitude if they have pre-existing ocular conditions or if they experience visual symptoms while at altitude. However, key outcomes have been contradictory and comprehensive studies are scarce, especially those pertaining to the choroid and retina. Such studies could not only deepen our understanding of high-altitude ocular pathophysiology, but could also offer valuable information and treatment possibilities for a constellation of other vision-threatening diseases.

The Large Hellenic Study of Uveitis: Diagnostic and Therapeutic Algorithms, Complications, and Final Outcome.

PURPOSE: The purpose of this study is to present the diagnostic and therapeutic algorithms, complications, and final outcome in the management of uveitic patients at a tertiary academic referral center. DESIGN: Observational study. METHODS: Analysis of the archives of 6191 uveitic patients at the Ocular Inflammation Service of the Department of Ophthalmology of the University Hospital of Ioannina in Greece from 1991 to 2020. RESULTS: During the 30 years of the study, the diagnostic ability climbed from 45.43% (1991-1995) to 73.4% (2016-2020). This improvement was linked to several factors including the increase in the number of diagnostic paracenteses for the analysis of intraocular fluids, the range and quality of laboratory blood tests, the multimodal ophthalmic imaging, the proper use of nonophthalmic imaging, and the multidisciplinary approach. The degree of uveitis-related complications was related to the severity and cause of inflammation, the recurrence rate, inappropriate treatment, and the prolonged or initially inactive inflammation. The 3 most common complications included cataract, macular edema, and glaucoma. Apart from the modern treatments and surgical techniques, the 3-month preoperative control of inflammation played a critical role in the surgical outcomes. The percentage of patients with a successful outcome increased from 72% (2001-2005) to 90.50% (2016-2020). The center's experience, prompt referral, patient's compliance, and regular follow-ups are associated with a better outcome. The analysis of the results allowed the development of diagnostic and therapeutic algorithms. CONCLUSIONS: Developing diagnostic and therapeutic algorithms allows for the efficient management of uveitis, leading to better visual outcome and therefore a better quality of life.

Impact of Cataract Surgery on IOP and Ocular Structures in Normotensive Patients and Primary and Exfoliation Open-Angle Glaucoma Patients.

Purpose: The aim of this study was to evaluate and compare the changes in Intraocular Pressure (IOP) and other ocular parameters: the Anterior Chamber Angle (ACA), Anterior Chamber Volume (ACV), and Anterior Chamber Depth (ACD) during phacoemulsification surgery in Greek patients with normotensive eyes and those with well-controlled Open-Angle Glaucoma (OAG). Additionally, parameters such as the Corneal Thickness (CCT), Axial Length (AL), Central Macular Thickness (CMT), and Retinal Nerve Fibre Layer (RNFL) were also examined. Patients and Methods: This was a prospective observational case-control study that included 50 phakic eyes, 25 normotensive (Group 1), and 25 with OAG: 15 Primary Open-Angle Glaucoma (POAG) and 10 Exfoliation Glaucoma (EXG) (Group 2). Ophthalmic assessment included IOP measurements, ocular biometry, and anterior and posterior segment optical coherence tomography evaluation of the aforementioned ocular parameters, prior and 6 months after phacoemulsification surgery. Results: At the 6 months post-operative review, a greater IOP reduction was recorded in eyes with OAG, in comparison to normotensive ones (5.3mmHg and 1.6 mmHg respectively). In addition, a significant but similar increase was recorded in the values of the ACA, ACV, and ACD of both groups between the pre- and the post-op period. Furthermore, the CCT and AL values remained unaltered. Finally, there was a non-statistically significant change in the mean CMT and the mean average RNFL of both groups. Conclusion: Eyes with OAG tend to undergo a greater reduction in IOP post-phacoemulsification surgery, in comparison to normotensive eyes. This reduction may not be solely attributed to ocular anatomical changes after phacoemulsification surgery but may also be due to the remodeling of the trabecular meshwork and the ciliary body. This may be especially true in the case of OAG eyes, which already start off with a compromised trabecular endothelium prior to surgery.

Evaluation of corneal hysteresis and corneal resistance factor after corneal cross-linking for keratoconus.

BACKGROUND: To evaluate corneal hysteresis (CH) and corneal resistance factor (CRF) in keratoconic (KC) eyes before and after corneal collagen cross-linking (CXL). Furthermore, to determine potential correlations with a series of corneal and demographic factors. METHODS: The study consisted of 50 KC eyes that underwent CXL. CH and CRF were measured by the ocular response analyzer (ORA). Correlations were attempted with uncorrected visual acuity (UVA), best spectacle-corrected visual acuity (BSCVA), central corneal thickness (CCT), mean keratometry (Km), astigmatism (Astig.), residual astigmatism, age, and gender. Fifty non-KC eyes served as controls. RESULTS: CH and CRF (mean ± SD) for non-KC eyes were 10.1 ± 1.9 mmHg and 9.7 ± 2.4 mmHg respectively, while for KC eyes preoperatively they were 8.2 ± 1.4 mmHg (p = 0.007) and 7.4 ± 2.3 mmHg (p = 0.01) respectively. Non-significant differences were detected between preoperative and postoperative CH and CRF measurements in KC eyes (p = 0.518 and p = 0.479 respectively). Significant correlations were found between ORA parameters and BSCVA, CCT, Km, Astig. and residual astigmatism. CONCLUSIONS: ORA parameters demonstrate significant differences between KC and non-KC eyes. Both CH and CRF present significant correlations with visual acuity and corneal parameters. CXL exerts a non-significant impact on ORA measurements.

Evaluation of the difference between intended and measured ablation and its impact on refractive outcomes of the wavefront optimize profile and the S001 Wellington nomogram in myopic spherocylindrical corrections.

BACKGROUND: To evaluate the level of agreement between intended and measured ablation of the wavefront optimize profile corrected by the Wellington nomogram in myopic spherocylindrical corrections and assess its impact on refractive outcomes. DESIGN: Prospective, university-institute setting. PARTICIPANTS: Eighty-six participants (86 eyes for photorefractive keratectomy group) and 86 participants (86 eyes for laser in situ keratomileusis group) recruited in a consecutive-if -eligible basis. METHODS: Differences between intended and measured ablation were evaluated with Scheimpflug camera. Refractive outcomes were evaluated by means of postoperative spherical equivalent, postoperative defocus equivalent, contrast sensitivity, correction index, difference vector and index of success. MAIN OUTCOME MEASURES: Correlation of visual outcomes with intended ablation. RESULTS: Both groups demonstrated significant over-ablations (16.7±8.5, P<0.001 & 11.8±18.5, P<0.001, respectively). Intended ablation was the primary determinant of the measured difference (r-square 0.769 & 0.765, respectively). Photorefractive keratectomy corrections over 100µ had significant impact on postoperative spherical equivalent, postoperative defocus equivalent, correction index, difference vector and index of success (P=0.044, P=0.05, P=0.019, P=0.016, P=0.006, respectively), but laser in situ keratomileusis corrections over 100µ had significant impact only on postoperative defocus equivalent, difference vector and index of success (P=0.04, P=0.05). CONCLUSIONS: The results suggest that the wavefront optimize profile seems to over-ablate corneal tissue both in photorefractive keratectomy and laser in situ keratomileusis. Over-ablation exerts significant impact on refractive outcomes only in high spherocylindrical corrections.

The Choroid after Half-Dose Photodynamic Therapy in Chronic Central Serous Chorioretinopathy.

PURPOSE: To characterize choroidal structure and vasculature after half-dose verteporfin photodynamic therapy (hd-vPDT) in eyes with chronic central serous chorioretinopathy using Enhanced Depth Imaging Optical Coherence Tomography (EDI OCT) and Optical Coherence Tomography Angiography (OCT-A). METHODS: This prospective case-control study included 10 eyes. Choroid was examined before and at 1 month following hd-vPDT. We measured choroidal thickness (CT) at subfoveal area and at 750 µm nasal and temporal of fovea and thickness of Haller and choriocapillaris/Sattler layers. Whole (WA), luminal (LA) and interstitial area (IA) at EDI-OCT, and perfusion density at OCT-A were analyzed. The unaffected fellow eyes were used for comparisons. RESULTS: Mean CT at subfoveal area and at 750 µm nasal and temporal of fovea, values of Haller and choriocapillaris/Sattler layers and those of WA, LA and IA were reduced, while PD increased at 1 month after hd-vPDT (all p < 0.001). There was a significant (p < 0.05) negative correlation (ρ = -0.658) between PD and post-treatment logMARVA. None of analyzed parameters reached values of unaffected fellow eye. CONCLUSION: Following hd-vPDT, choroidal thickness with both luminal and interstitial components markedly decreased, while perfusion of choriocapillaris improved.