Diagnostic Importance of OCT Pachymetry in Keratoconus.

AIMS: To demonstrate changes in distance and near fusional vergence measured with prism bars, while compensating for present heterophoria using current ametropia correction. In addition, to determine the differences in values of the AC/A ratio determined by the heterophoric (calculation) and gradient methods. MATERIAL AND METHODS: The basic sample includes 19 subjects with a mean age of 21.5 ±3.0 years (min. 18, max. 27). We used the Von Graefe technique for examination of distance and near phoria, and prism bars for examination of fusion vergences measured in prism diopters. We divided the basic cohort into six research sets according to the size of distance and near heterophoria. This was a cohort of patients with distance (D OR) and near orthophoria (N OR), a cohort of patients with distance (D EX) and near exophoria (N EX) and a set of patients with distance (D ES) and near esophoria (N ES). RESULTS: In the case of both groups with exophoria (distance, near) we found a statistically significant result only for negative fusion vergence (NFV). There was a statistically significant increase in NFV in the sample with distance and near exophoria (D EX, p = 0.01 and B EX, p = 0.02, respectively). In our study, we also demonstrated a statistically significant difference (p < 0.001) in the values of the AC/A ratio measured by the gradient and heterophoric methods. The values determined by the gradient method are lower (3.0 ±1.1 pD/D versus 5.8 ±0.9 pD/D) than by the heterophoric method. CONCLUSION: By comparing fusion vergence values in patients with exophoria and orthophoria, we demonstrated that in the presence of distance or near exophoria there is an increase in ipsilateral fusion vergence. In the case of an increase in ipsilateral fusion vergence, the finding was statistically significant both distance and near (p = 0.01 and p = 0.02, respectively). By contrast, we were unable to prove this fact in the group of patients with esophoria. In our study, we also demonstrated a statistically significant difference (p < 0.001) in the values of the AC/A ratio measured by the gradient and heterophoric methods. The values determined by the gradient method are lower (3.0 ±1.1 pD/D versus 5.8 ±0.9 pD/D) than by the heterophoric method.

Virtual Reality Visual Training in an Adult Patient with Anisometropic Amblyopia: Visual and Functional Magnetic Resonance Outcomes.

A case of an adult with anisometropic amblyopia who underwent a successful vision therapy program playing videogames in a virtual reality environment is described, reporting changes in conventional visual clinical data, as well as in brain activity. The patient was a 22 year old man on baseline examination that never previously wore correction for his anisometropia. After prescribing contact lens correction for the anisometropia and after 44 h of virtual reality-based vision therapy over a period of 1.5 years, the best corrected distance visual acuity (BCDVA) in the amblyopic eye improved from 0.05 to 0.5 (Sloan chart). One year after finishing the visual training, the BCDVA experienced a slight decrease to 0.4 (Sloan chart). Through the visual training, the patient gradually developed stereopsis. Likewise, changes were also detected after visual therapy on functional magnetic resonance imaging while the patient was viewing 2D and 3D stimuli. The preliminary results of this case show the potential of using virtual reality-based visual training as a treatment for adult amblyopia.

A Marker-Less Registration Approach for Mixed Reality-Aided Maxillofacial Surgery: a Pilot Evaluation.

As of common routine in tumor resections, surgeons rely on local examinations of the removed tissues and on the swiftly made microscopy findings of the pathologist, which are based on intraoperatively taken tissue probes. This approach may imply an extended duration of the operation, increased effort for the medical staff, and longer occupancy of the operating room (OR). Mixed reality technologies, and particularly augmented reality, have already been applied in surgical scenarios with positive initial outcomes. Nonetheless, these methods have used manual or marker-based registration. In this work, we design an application for a marker-less registration of PET-CT information for a patient. The algorithm combines facial landmarks extracted from an RGB video stream, and the so-called Spatial-Mapping API provided by the HMD Microsoft HoloLens. The accuracy of the system is compared with a marker-based approach, and the opinions of field specialists have been collected during a demonstration. A survey based on the standard ISO-9241/110 has been designed for this purpose. The measurements show an average positioning error along the three axes of (x, y, z) = (3.3 ± 2.3, - 4.5 ± 2.9, - 9.3 ± 6.1) mm. Compared with the marker-based approach, this shows an increment of the positioning error of approx. 3 mm along two dimensions (x, y), which might be due to the absence of explicit markers. The application has been positively evaluated by the specialists; they have shown interest in continued further work and contributed to the development process with constructive criticism.

Presbyopic lens exchange (PRELEX) cataract surgery outcomes with implantation of a rotationally asymmetric refractive multifocal intraocular lens: femtosecond laser-assisted versus manual phacoemulsification.

PURPOSE: To compare the visual and refractive outcomes obtained with the implantation of a rotationally asymmetric refractive multifocal IOL after femtosecond laser-assisted cataract surgery (FLACS) and conventional lens extraction (CLE). METHODS: A total of 78 eyes of 58 patients that had undergone conventional phacoemulsification (36 eyes, CLE group) or FLACS (37 eyes, FLACS group) with the implantation of the toric multifocal IOL LU-313 MF30T (Oculentis, Germany) were enrolled in this retrospective study. Mean age was 57.0 years at the time of surgery, ranging from 44 to 69 years. Visual and refractive outcomes were evaluated during a 12-month follow-up. Likewise, contrast sensitivity was assessed at the end of the follow-up. RESULTS: Significant improvements were observed in both groups in uncorrected distance (UDVA) and near visual acuity (UNVA) at 1 month postoperatively (p < 0.001). Differences between groups in these parameters as well as in sphere and cylinder did not reach statistical significance during the whole follow-up (p ≥ 0.079), except for UNVA only at 12 months postoperatively (p = 0.018). Concerning corrected near visual acuity, only significant differences between groups were found preoperatively (p = 0.020). Furthermore, only a minimal but significant difference between groups was found at 12 months postoperatively in contrast sensitivity for the spatial frequency of 18 cycles/° (p = 0.029). CONCLUSIONS: The rotationally asymmetric toric multifocal IOL LU-313 MF 30T provides good visual rehabilitation for near and distance vision after presbyopic lens extraction in eyes with preexisting astigmatism, independently whether the cataract surgery is performed with the FLACS or conventional technique.

Disorganization of retinal inner layers correlates with ellipsoid zone disruption and retinal nerve fiber layer thinning in diabetic retinopathy.

PURPOSE: To study the correlation between disorganization of inner retinal layer (DRIL) and macular thickness parameters, ellipsoid zone (EZ) disruption and retinal nerve fiber layer (RNFL) thickness on spectral domain optical coherence tomography (SD-OCT) in diabetic retinopathy (DR), for the first time. METHODS: A tertiary care center-based cross-sectional study was undertaken. One hundred and four consecutive study subjects of type 2 diabetes mellitus were included: diabetes mellitus with no retinopathy (No DR) (n = 26); non-proliferative DR (NPDR) (n = 26); proliferative DR (PDR) (n = 26) and healthy controls (n = 26). Best Corrected Visual Acuity (BCVA) was measured on the logarithm of the minimum angle of resolution (logMAR) scale. Clinician-friendly, SD-OCT based, grading systems were created for DRIL and EZ disruption, within the macular cube. DRIL was graded as: grade 0, DRIL absent; and grade 1, DRIL present. EZ disruption was graded as; Grade 0: Intact EZ; Grade 1: Focal disruption and Grade 2: Global disruption. Every study subject underwent RNFL thickness analysis. RESULTS: DRIL was significantly associated with increase in severity of DR.Pearson correlation analysis showed significant positive correlation between DRIL and CST CAT and grades of EZ disruption . However, a significant negative correlation was found between DRIL and RNFL thickness . CONCLUSION: Presence of DRIL correlates with severity of DR, EZ disruption and RNFL thinning.

Retinal photoreceptor apoptosis is associated with impaired serum ionized calcium homeostasis in diabetic retinopathy: An in-vivo analysis.

PURPOSE: The aim of this work was to study the association of serum ionized calcium with retinal photoreceptor apoptosis on spectral domain optical coherence tomography (SD-OCT) in diabetic retinopathy (DR). METHODS: Sixty consecutive cases with Type 2 diabetes mellitus were categorized into three groups: no diabetic retinopathy; non-proliferative DR; proliferative DR. The eye with more severe form of the disease was considered. Twenty healthy controls were also included. Best corrected visual acuity (BCVA) was measured on logMAR scale. Retinal photoreceptor apoptosis was defined as disruption of retinal photoreceptor ellipsoid zone (EZ). Ellipsoid zone disruption was assessed using SD-OCT. Serum levels of total and ionized calcium were measured using standard protocol. RESULTS: EZ disruption was found to be positively associated with serum total calcium and ionized calcium. Also, EZ disruption was found to be positively associated with logMAR BCVA. CONCLUSION: Increased serum ionized calcium induces retinal photoreceptor apoptosis resulting in increased EZ disruption in DR.

Genetic association of single nucleotide polymorphisms of FZD4 and BDNF genes with retinopathy of prematurity.

BACKGROUND: Retinopathy of prematurity (ROP) is a multifactorial disease occurring in preterm neonates, caused by incorrect development of retinal blood vessels. It has been suggested that, in addition to gestational age, weight, and oxygen supplementation, genetic factors can play a role in the pathogenesis of ROP. METHODS: In the present prospective study, 97 neonates were enrolled based on the gestational age and weight, and genomic DNA from patients diagnosed with ROP and premature newborns without ROP was collected. The DNA sequence of protein coding and 5´and 3´ untranslated regions (UTRs) of the frizzled-4 (FZD4) gene and the genotype of the locus rs7934165:G˃A (NM_170731.4: c.3 + 10976 C˃T) within the brain-derived neurotrophic factor gene (BDNF) were determined. RESULTS: We detected a significant association between rs61749246:C˃A (NM_012193.3: c.*2G˃T) and ROP in a general genetic model as well as in a multiplicative model and by the Cochran-Armitage test for trend. Moreover, rs61749246 was strongly associated with ROP, requiring surgical intervention. CONCLUSION: We suggest that rs61749246:C˃A of the FZD4 gene is likely associated with the development of ROP. It is necessary to confirm this suggestion in larger studies.

Postoperative visual performance with a bifocal and trifocal diffractive intraocular lens during a 1-year follow-up.

AIM: To evaluate and compare the clinical outcomes with a diffractive bifocal and trifocal intraocular lens (IOL) during a 12-month follow-up. METHODS: Prospective comparative study including 75 eyes of 38 patients (44-70y) undergoing uneventful cataract surgery. Each patient was randomly assigned to one type of IOL, bifocal (35 eyes) or trifocal (40 eyes). Visual, refractive, and contrast sensitivity changes were evaluated in a 12-month follow-up. The binocular defocus curve was also measured at 12mo postoperatively. RESULTS: No statistically significant differences between groups were found in postoperative uncorrected and corrected distance visual acuities (P≥0.276). Postoperative corrected near visual acuity (33 cm) was significantly better in the trifocal group during all follow-up (P≤0.004) as well as 6-month uncorrected near (P=0.008) and distance-corrected near visual acuities (P=0.016) (33/40 cm). Significantly better uncorrected intermediate and distance corrected-intermediate visual acuity were found during all follow-up in the trifocal group (P<0.001), which was consistent with differences among groups in binocular defocus curve. Differences among groups in contrast sensitivity were minimal, being only significant at 6 months for some low to medium spatial frequencies (P≤0.006). CONCLUSION: Bifocal and trifocal diffractive IOLs are able to provide an effective visual restoration which is maintained during a 12-month follow-up, with a clear benefit of the trifocal IOL for the intermediate vision.

Amblyopia treatment of adults with dichoptic training using the virtual reality oculus rift head mounted display: preliminary results.

BACKGROUND: The gold standard treatments in amblyopia are penalizing therapies, such as patching or blurring vision with atropine that are aimed at forcing the use of the amblyopic eye. However, in the last years, new therapies are being developed and validated, such as dichoptic visual training, aimed at stimulating the amblyopic eye and eliminating the interocular supression. PURPOSE: To evaluate the effect of dichoptic visual training using a virtual reality head mounted display in a sample of anisometropic amblyopic adults and to evaluate the potential usefulness of this option of treatment. METHODS: A total of 17 subjects (10 men, 7 women) with a mean age of 31.2 years (range, 17-69 year) and anisometropic amblyopia were enrolled. Best corrected visual acuity (BCVA) and stereoacuity (Stereo Randot graded circle test) changes were evaluated after 8 sessions (40 min per session) of dichoptic training with the computer game Diplopia Game (Vivid Vision) run in the Oculus Rift OC DK2 virtual reality head mounted display (Oculus VR). RESULTS: Mean BCVA in amblyopic eye improved significantly from a logMAR value of 0.58 ± 0.35 before training to a post-training value of 0.43 ± 0.38 (p < 0.01). Forty-seven percent of the participants achieved BCVA of 20/40 or better after the training as compared to 30% before the training. Mean stereoacuity changed from a value of 263.3 ± 135.1 before dichoptic training to a value of 176.7 ± 152.4 s of arc after training (p < 0.01). A total of 8 patients (47.1%) before dichoptic treatment had unmeasurable stereoacuity while this only occurred in 2 patients (11.8%) after training. CONCLUSIONS: Dichoptic training using a virtual reality head mounted display seems to be an effective option of treatment in adults with anisometropic amblyopia. Future clinical trials are needed to confirm this preliminary evidence. TRIAL REGISTRATION: Trial ID: ISRCTN62086471 . Date registered: 13/06/2017. Retrospectively registered.

Visual Evoked Potential and Magnetic Resonance Imaging are More Effective Markers of Multiple Sclerosis Progression than Laser Polarimetry with Variable Corneal Compensation.

BACKGROUND: The aim of our study was to assess the role of laser polarimetry and visual evoked potentials (VEP) as potential biomarkers of disease progression in multiple sclerosis (MS). PARTICIPANTS: A total of 41 patients with MS (82 eyes) and 22 age-related healthy volunteers (44 eyes) completed the study. MS patients were divided into two groups, one (ON) with a history of optic neuritis (17 patients, 34 eyes) and another group (NON) without it (24 patients, 48 eyes). The MS patients and controls underwent laser polarimetry (GDx) examination of the retinal nerve fiber layer (RNFL). In the MS group, we also examined: Kurtzke "expanded disability status scale" (EDSS), the duration of the disorder, VEP - latency and amplitude, and conventional brain magnetic resonance imaging (MRI). Our results were statistically analyzed using ANOVA, Mann-Whitney, and Spearman correlation analyses. RESULTS: In the MS group, brain atrophy and new T2 brain lesions in MRI correlated with both VEP latencies and amplitudes. Separate comparisons revealed VEP latency testing to be less sensitive in ON than in NON-patients. In ON patients, VEP amplitudes correlated mildly with brain atrophy (r = -0.15) and strongly with brain new MRI lesions (r = -0.8). In NON-patients, highly significant correlation of new MRI brain lesions with VEP latencies (r = 0.63, r = 0.6) and amplitudes (r = -0.3, r = -4.2) was found. EDSS also correlated with brain atrophy in this group (r = 0.5). Our study did not find a correlation of GDx measures with MRI tests. The GDx method was not able to detect whole brain demyelinization and the degeneration process, but was only able to reveal the involvement of optic nerves in ON and NON-patients. CONCLUSION: In our study, we found that both methods (VEP and GDx) can be used for the detection of optic nerve damage, but VEP was found to be superior in evaluating whole brain demyelinization and axonal degeneration. Both VEP and MRI, but not GDx, have an important role in monitoring disease progression in MS patients, independent of the ON history.

Outcomes of a new diffractive trifocal intraocular lens.

PURPOSE: To evaluate refractive and visual parameters related to distance, intermediate, and near vision after cataract surgery and the optical quality of a new diffractive trifocal intraocular lens (IOL). SETTING: Vissum Instituto Oftalmologico de Alicante, Alicante, Spain. DESIGN: Case series. METHODS: Patients had bilateral refractive lens exchange and multifocal diffractive IOL (AT Lisa tri 839 MP) implantation. A complete ophthalmology examination was performed preoperatively and postoperatively. The follow-up was 6 months. The main outcome measures were uncorrected distance (UDVA) and corrected distance (CDVA), intermediate, and near visual acuities; keratometry; manifest refraction; and aberrations (total, corneal, internal). RESULTS: The study comprised 60 eyes of 30 patients (mean age 57.9 years ± 7.8 [SD]; range 42 to 76 years). There was significant improvement in UDVA, uncorrected intermediate visual acuity, uncorrected near visual acuity, CDVA, and distance-corrected intermediate and near visual acuity. The postoperative refractive status was within the range of +1.00 to -1.00 diopter. Total internal aberrations decreased significantly (P<.001). CONCLUSIONS: The trifocal IOL improved near, intermediate, and distance vision in presbyopic patients. The use of 3 foci provided significant intermediate visual results without sacrificing near or distance vision.

First cases of Acanthamoeba keratitis in Slovakia.

We present the case report of the first identification of Acanthamoeba as a causative agent of keratitis in the Slovak Republic. For the first time, Acanthamoeba sp. Group III was isolated from a 53-year-old patient with keratitis, which was manifested after an injury of the right eye. A delayed visit to a physician as well as a late diagnosis of the illness led to the advanced stage of eye disease. As the treatment with itraconazol and cornea transplantation showed no result, enucleation of the eye was decided. Acanthamoeba ludgunensis was also the causative agent of keratitis in a 39-year-old patient wearing contact lenses. His complaints occurred a month after bathing in a thermal swimming pool. The symptoms presented in the left eye were those of herpetic keratitis, and led to a cloudy cornea with circular infliltrate and poor vision. A prompt clinical and laboratory diagnosis, along with treatment with propamidine-isetionate resulted in a significant improvement of the eye condition. Contact lenses were probably related to another case of Acanthamoeba keratitis. The patient, a 15-year-old girl, kept wearing contact lenses during bathing in various swimming pools and in the sea; her contact lenses were also regularly washed under tap water. Due to the fact that cysts of Acanthamoeba sp. group II were found in the contact lens solution, this is presumed to be the source of the eye infection.