Photoactivated Chromophore Corneal Collagen Cross-Linking for Infectious Keratitis (PACK-CXL)-A Comprehensive Review of Diagnostic and Prognostic Factors Involved in Therapeutic Indications and Contraindications

Infectious keratitis is a severe infection of the eye, which requires urgent care in order to prevent permanent complications. Typical cases are usually diagnosed clinically, whereas severe cases also require additional tools, such as direct microscopy, corneal cultures, molecular techniques, or ophthalmic imaging. The initial treatment is empirical, based on the suspected etiology, and is later adjusted as needed. It ranges from topical administration of active substances to oral drugs, or to complex surgeries in advanced situations. A novel alternative is represented by Photoactivated Chromophore Corneal Collagen Cross-Linking (PACK-CXL), which is widely known as a minimally invasive therapy for corneal degenerations. The purpose of this review is to identify the main diagnostic and prognostic factors which further outline the indications and contraindications of PACK-CXL in infectious keratitis. Given the predominantly positive outcomes in the medical literature, we ponder whether this is a promising treatment modality, which should be further evaluated in a systematic, evidence-based manner in order to develop a clear treatment protocol for successful future results, especially in carefully selected cases.

Choroidal Thickness Increase after Subliminal Transscleral Cyclophotocoagulation

Background: The purpose of this study is to estimate the success rate of subliminal transscleral cyclophotocoagulation for refractory glaucoma and to determine the correlation between the decrease in intraocular pressure and the variation in choroidal thickness. Methods: A pre−post study was conducted over a period of 3 years, including 81 eyes from 67 patients with different types of drug-refractory glaucoma who underwent subliminal transscleral cyclophotocoagulation. The variables included best-corrected visual acuity, intraocular pressure and choroidal thickness. Results: We observed the following success rates (defined as IOP < 21 mmHg): 80% at 1 month (65 patients), 74% at 3 months (60 patients), 64% at 6 months (52 patients) and 50.6% at 1 year (41 patients). A strong correlation was noted between the decrease in intraocular pressure and the increase in the average choroidal thickness at 1 year (318.42 µm) compared to the average preoperative thickness (291.78 µm). A correlation of increased choroidal thickness at 1-month with the success rate of the procedure was also observed. Conclusions: We observed a statistically significant correlation between the success rate, decrease in intraocular pressure and choroidal thickness. The correlation of increased choroidal thickness at 1-month with the success rate of the procedure could be used clinically as a predictive factor for the final outcome of patients. Further experimental research is warranted to determine whether the increase in choroidal thickness after subliminal transscleral cyclophotocoagulation is indeed evidence of increased uveoscleral drainage.

Central serous chorioretinopathy in pregnancy

Objective: The objective of this work was to present two unusual cases of central serous chorioretinopathy (CSC) and the chosen therapeutic method. Materials and methods: In this article, two cases of CSC in pregnant patients were described. Results: The first case was a 35-year-old patient in the 16th week of pregnancy and the second one was a 26-year-old patient in the 20th week of pregnancy. Due to the contraindications associated to pregnancy, the therapeutic method chosen was subthreshold micropulse laser photocoagulation. The functional and anatomical evolution was very good in both patients. Discussion: In both cases, treatment of the disease was preferred to prevent important photoreceptor losses. After the treatment, very good anatomical and functional results were obtained. Conclusions: The micropulse laser is an effective solution for treating CSC. It is the only safe therapeutic solution during pregnancy. CSC can be associated with pregnancy, without necessarily suggesting pre-eclampsia. Abbreviations: CSC = central serous chorioretinopathy, SRF = subretinal fluid.

Investigation of Retinal Microcirculation in Diabetic Patients Using Adaptive Optics Ophthalmoscopy and Optical Coherence Angiography

The current research approaches the retinal microvasculature of healthy volunteers (17 subjects), patients with diabetes mellitus without retinopathy (19 subjects), and of diabetic patients with nonproliferative (17 subjects) and proliferative (21 subjects) diabetic retinopathy, by using adaptive optics ophthalmoscopy and optical coherence ophthalmoscopy angiography. For each imaging technique, several vascular parameters have been calculated in order to achieve a comparative analysis of these imaging biomarkers between the four studied groups. The results suggest that diabetic patients with or without diabetic retinopathy prove signs of retinal arteriole structural alterations, mainly showed by altered values of wall to lumen ratio, calculated for the superior or inferior temporal branch of the central retinal artery, near the optic nerve head, and significant changes of the vascular density in the retinal superficial capillary plexus. Both adaptive optics ophthalmoscopy and optical coherence ophthalmoscopy angiography are providing useful information about the retinal microvasculature from early onset of diabetic disease, having a promising diagnostic and prognostic role in the future.

High-resolution images in macular disorders

Objective: This study analyzed and compared the results of adaptive optics (AO) and fundus autofluorescence (FAF) in various maculopathies.

Methods: The study included four different types of maculopathy: central serous chorioretinopathy (CSC), retinitis pigmentosa (RP), Stargardt disease (STGD) and phototoxic retinopathy. In all four cases, cone mosaic and cone density were obtained using AO fundus camera. Further, the high-resolution images were compared with the FAF and optical coherence tomography (OCT) results.

Results: In CSC, FAF and AO, changes could be shown in the macula even two years after the subretinal fluid resorption, as opposed to a normal OCT. The improvement of FAF and cone mosaic appearance was concomitant with the visual acuity growth. Several cone mosaic phenotypes were observed in RP and STGD. In RP, the cone density was 24.240 cones /mm2 in the center, and decreased to 8.163 cones/ mm2 in the parafoveal area. In STGD, the cone density was lower in the center, 9.219 cones/ mm2, and higher at the periphery, 12.594 cones/ mm2. In the case of phototoxic retinopathy, AO and OCT were more effective than FAF in highlighting the photoreceptor and retinal pigment epithelium lesions.

Conclusions: FAF and AO are very useful tools in macular pathologies examination. FAF can offer a true picture of the metabolic changes in the macula, while AO allows the view of changes up to the cellular level.

Abbreviations: STGD = Stargardt disease, CSC = central serous chorioretinopathy, RP = retinitis pigmentosa, AO = adaptive optics, FAF = fundus autofluorescence

Cumulative visual impact of two coagulability disorders: A case report

Cumulative visual impact of two coagulability disorders were reviewed by presenting a case of a young female patient with a spontaneous abortion and two thromboembolic events in 8 years, whose visual function was severely affected. The particularities of her genetic constellation regarding the retinal circulation are also discussed. The patient developed a central retinal artery occlusion in the right eye during pregnancy in 2010, which led to an extended hematological workup that revealed presence of MTHFR C677T and MTHFR A1298C heterozygote mutations. The screening for myeloproliferative disorders showed JAK2 V617F gene mutation. Test results confirmed the diagnosis of thrombophilia and essential thrombocythemia and she was recommended permanent treatment with low molecular weight heparin, platelet antiaggregant, peripheral vasodilator and neuroprotectors. Despite the treatment, the patient developed central retinal vein occlusion in the fellow eye 8 years after the first thromboembolic event. The visual acuity for the right eye (0.9 logMAR) remained poor and the visual acuity for the left eye recovered completely (from 0.3 logMAR to 0 logMAR). However, new retinal artery or vein occlusions could occur in the future and there is also a risk of thrombosis in other areas, such as cerebral, pulmonary or renal, due to the general coagulability imbalance.

Photoreceptor assessment in focal laser-treated central serous chorioretinopathy using adaptive optics and fundus autofluorescence

This study analyzed cone density, cone mosaic, and fundus autofluorescence (FAF) images in patients with focal laser-treated central serous chorioretinopathy (CSC).Observational case series.Forty-two eyes of 21 patients with unilateral treated CSC and bilateral best-corrected visual acuity of 1.0 (decimal fraction) were included. FAF and cone mosaic images were obtained in all patients with an adaptive optics fundus camera. Densities were recorded at 20 points throughout the macula, and choroidal thicknesses were measured.Mean choroidal thicknesses were 419.95 ± 110.33 μm in normal eyes, 459.09 ± 90.07 μm in eyes with active CSC, and 438.61 ± 107.57 μm in treated eyes. The highest density of cones in healthy eyes was 38146 cones/mm, with a 5.66-μm intercellular space (IS), at 700 μm temporal to the center. In eyes with treated CSC, the highest density was 32749 cones/mm, with a 6.13-μm IS, at 500 μm nasal to the center. In all quadrants, median values of maximum cone density were significantly higher in healthy eyes (P = .02, P = .003, P = .0001, and P = .001). Three types of lesions were identified on FAF and were correlated with those on cone mosaic images. Strong correlations were detected between the presence of hypoautofluorescent lesions on the first FAF image and a greater difference between maximum values of photoreceptor density (r = 0.46, P = .03), as well as between the presence of hypoautofluorescent lesions and the duration of pathology (r = 0.68, P < .001).The presence of hypoautofluorescent lesions and the duration of pathology were negative prognostic factors in CSC. Laser treatment could prevent photoreceptor loss.

Cone photoreceptor density in type I diabetic patients measured with an adaptive optics retinal camera

Purpose: To assess the variation in cone photoreceptor density on the basis of age compatibility between healthy subjects, on one side, and type 1 diabetic patients with no diabetic retinopathy, on the other. Methods: A high resolution adaptive optics retinal camera in flood illumination regime was employed to image cones of 15 type I diabetic patients and 16 healthy controls. For each subject we scanned the cone mosaic in 4 perifoveal areas (nasally, temporally, superiorly and inferiorly) at 2, 3 and 4 degrees eccentricity. The impact of diabetes duration, gender and age were evaluated. Results: In the type I diabetic group we found a meaningful lower cone density (p<0.05), except for the temporal meridian at 2 and 4 degrees eccentricity. Moreover, a significant asymmetry of cone photoreceptor densities was proved between the horizontal and vertical meridians in both diabetic and control groups. Conclusion: The rtx1 retinal image evaluation demonstrated photoreceptors loss in DM1 diabetic patients prior to any clinical changes. Abbreviations: AO = adaptive optics, SS = swept source, OCT = optical coherence tomography, BCVA= best corrected visual acuity, DM = diabetes mellitus, DR = diabetic retinopathy.

[Treatment for penetrating wound caused by metallic intraocular foreign body]

INTRODUCTION

Penetrating wounds with intraocular foreign body are ophthalmologic emergencies due to their severity and complexity and may require multiple surgeries for final resolution.

CASE REPORT

30-years-old patient with penetrating wound and metallic intraocular foreign body in the posterior vitreous requires successive operations for IOFB extraction, lensectomy, posterior vitrectomy for rhegmatogenous retinal detachment and then silicone oil extraction with final visual acuity 0, 4 PH.

Refractory secondary glaucoma-clinical case

RATIONALE AND OBJECTIVE

The major objective of treatment in glaucomatous disease is the decrease of intraocular pressure while maintaining the patient's vision and quality of life. Despite therapeutic possibilities, some cases of glaucoma remain refractory to treatment with the maintenance of elevated intraocular pressure and further progression of the disease.Artificial drainage systems, Ahmed valve, is a treatment alternative for refractory glaucoma when medical therapy, laser or conventional surgery have shown no results.

METHODS AND RESULTS

We present the case of a patient presenting with refractive to medical treatment secondary glaucoma, following cataract surgery and vitrectomy for retinal detachment.

DISCUSSIONS

One of the complications of vitreoretinal surgery is secondary glaucoma. Some of the patients with this type of glaucoma are unresponsive to conventional medical therapy. In such situations, a DPS implantation is needed such as an Ahmed valve in our case. There are situations in which classical surgery-trabeculectomy--has no theoretical chance of success (in cases of neovascular glaucoma, secondary glaucoma, and inflammatory glaucoma post vitreoretinal surgery), [5,6]. Even though ASD are only used for refractory glaucoma, in this type of glaucoma, ADS can be used successfully as first line surgery.

[Current therapeutic approach to diabetic macular edema refractory to laser coagulation]

The paper presents the evolution of a diabetic patient with CSME resistant to laser treatment. The intravitreal injection of Triamcinolone Acetonid represented a very efficient therapeutic solution the visual accuity improving for a period of 7-9 months.

[Transluminal embolysis with Yag-Nd-laser]

Transluminal YAG laser embolysis (TYE) could be a therapeutical approach for retinal vascular occlusive diseases. The main indication is branch retinal artery occlusion with visible embolus. We are proud to present three BRAO cases managed successfully using TYE technique.

Protein kinase C and the antiviral effect of human interferon

Protein kinase C (PKC) inhibitors: Hidaka's compounds H-7 (10 microM) and H-8 (20 microM), palmitoyl-carnitine (10 microM) and phloretin (50 microM), did not modify the antiviral effect of human natural or recombinant interferon alpha and of natural interferon beta. The tumor promoter 12-o-tetradecanoyl-phorbol-13-acetate (TPA) (200 nM), known as activator of PKC induced an antiviral state when tested on human embryo fibroblasts challenged with the vesicular stomatitis virus. The battery of PKC inhibitors used inhibited the antiviral effect induced by TPA. Palmitoyl-carnitine (10 microM) exerted a toxic effect that was reversed by interferon treatment (2,000 IU/ml interferon alpha). These results suggest that PKC, possibly activated by interferon-receptor interaction, is not essential for inducing the antiviral effect of interferon, but, probably, mediates the antiviral effect of TPA.

Interferon: signal molecules involved in its antiviral effect

A major problem concerning interferon (IFN)-cell interaction is the second messenger system that transduces the IFN signal. We discuss the evidences existing in literature and our arguments which suggest that the antiviral effect of IFNs alpha and beta are mediated by a membrane mechanism including a phospholipase C dependent hydrolysis of phosphoinositides. The resulting two second messengers: diacylglycerol and inositol triphosphate and subsequent, separate but interacting, signal pathways: activation of protein kinase C and ionic events are tested in respect with the antiviral effect of IFN.

Interferon-induced antiviral state is inhibited by neomycin and mimicked by diacylglycerols

The antiviral effect of human interferons alpha and beta was inhibited in dose-dependent manner by submillimolar concentrations of neomycin, known to block phosphoinositide hydrolysis and therefore the diacylglycerol formation. On the contrary, the synthetic permeant diacylglycerols (1-oleoyl-2-acetyl-sn or rac-glycerol) were able to induce an interferon-like antiviral state when tested against the vesicular stomatitis virus and herpes simplex type I virus. Hidaka's compound H-8 (1.2 microM), expected to inhibit cAMP- and cGMP-dependent protein kinases, did not modify the antiviral effect of interferon. Our data suggest that the phosphoinositide pathway is involved in transducing the interferon antiviral signal, but, since the exogenous phospholipase C (0.1-1 U/ml) failed to induce an antiviral state, this pathway, although implicated, seems not the only one.

The antiviral effect of human interferon alpha is dependent on phosphoinositide-derived messengers

Neomycin the putative blocker of membrane polyphosphoinositide hydrolysis, inhibited the antiviral activity of human interferon alpha, when tested on human quiescent fibroblasts challenged with vesicular stomatitis virus. The anti-interferon effect of neomycin could be correlated in terms of dose dependence for both neomycin (0.05-1 mM) and interferon (100-5,000 IU/ml). The results suggest that the antiviral activity of interferon alpha depends on diacylglycerol formation. Indeed, the synthetic diacylglycerol (50 microM) was as effective as 100 IU/ml interferon in inducing the antiviral state.