Aqueous humor dynamics in inbred rhesus monkeys with naturally occurring ocular hypertension

This study evaluates aqueous humor dynamics in rhesus monkeys from the University of Florida inbred colony with ocular normotension and naturally occurring ocular hypertension. Eight monkeys with untreated intraocular pressures (IOPs) of less than 18 mmHg in one eye (ONT group) and seven with untreated IOPs of greater than or equal to 18 mmHg in one eye (OHT group) were included in the study. Assessments included central cornea thickness by ultrasound pachymetry, IOP by tonometry, aqueous flow and outflow facility by fluorophotometry, and uveoscleral outflow by mathematical calculation. Animals were sedated with ketamine for all measurements. Values from the two eyes of each animal were averaged, with the exception of one animal that had only one good eye. Comparisons between groups were made by Student’s two-tailed unpaired t-tests. Compared to the ONT group, the OHT group had higher IOPs at all times measured (4:00 PM the day before the study, 21.2 ± 6.5 versus 14.4 ± 1.5 mmHg, p = 0.01; 9:00 AM the day of the study, 20.7 ± 6.6 versus 14.8 ± 1.2 mmHg, p = 0.03; 11:00 AM the day of the study, 16.0 ± 1.6 versus 13.3 ± 2.9 mmHg, p = 0.05) and lower aqueous flow (2.12 ± 0.40 versus 4.54 ± 1.11 μl/min, p = 0.0001), outflow facility (0.17 ± 0.10 versus 0.33 ± 0.07 μl/min/mmHg, p = 0.01) and uveoscleral outflow (p < 0.05). The elevated IOP in inbred Florida rhesus monkeys is a result of significantly reduced outflow facility and uveoscleral outflow. These animals also have slower aqueous flow than the ONT animals which does not contribute to the higher IOP.     

Efficacy and safety of the mineralocorticoid receptor antagonist treatment for central serous chorioretinopathy: a systematic review and meta-analysis

ObjectivesWe performed a systematic review and meta-analysis to assess the efficacy and safety of the mineralocorticoid receptor antagonist (MRA) treatment for central serous chorioretinopathy (CSC).MethodsWe searched the PubMed, Embase, and the Cochrane Library to identify relevant clinical studies published prior to March 2020. The primary outcome was change in best-corrected visual acuity (BCVA), and the secondary outcomes included the subretinal fluid (SRF), subfoveal choroidal thickness (SFCT), and central macular thickness (CMT).ResultsFive randomized controlled trials (RCT) and four cohort studies met the inclusion criteria with a total of 352 eyes. The MRA treatment was not superior to placebo in BCVA at 1 month (WMD = −0.06, 95% CI −0.15–0.02, P = 0.15, I² = 86%), 3 months (WMD = −0.04, 95% CI −0.14–0.06, P = 0.44, I² = 77%) and 6 months (WMD = −0, 95% CI −0.05–0.05, P = 0.92, I² = 0%). The MRA treatment resulted in significant reduction than the placebo in the SRF (WMD = −60.64, 95% CI −97.91 to −23.37, P = 0.001, I² = 49%), SFCT (WMD = −39.15, 95% CI −52.58 to −25.72, P < 0.001, I² = 0%), and CMT (WMD = −60.75, 95% CI −97.85 to −23.65, P = 0.01, I² = 53%).ConclusionsOur meta-analysis shows that the MRA treatment can improve anatomical structure in CSC patients, but it is not effective for achieving BCVA gain. The applicant of the MRA is safe and have no severe effect.Subject terms: Prognostic markers, Retinal diseases     

Retinoarteriosklerose - Organarteriosklerose - Generalisierte Arteriosklerose

Zusammenfassung Darstellung der klinischen, histopathologischen und neuropathologischen Verfahren zur qualitativen und quantitativen Erfassung arteriosklerotischer Veränderungen. Zugrundegelegt werden Untersuchungen an Auge, Hirn, Niere, Coronargefäßen und Aorta, sowie an den großen Körpergefäßen (125 Fälle). Erörterung des differentialdiagnostischen Wertes der Retinagefäßveränderungen bei Hirnarteriosklerose, seniler Demenz, Organarteriosklerose und sog. generalisierter Arteriosklerose.

---

Summary Presentation of clinical, histopathological and neuropathological methods for qualitative and quantitative determination of arteriosclerotical changes. Fundaments are the investigations of eye, brain, kidney, coronary vessels and aorta, and the larger body-vessels (125 patients). Discussion on the importance for differential diagnosis of changes of the retina vessels in case of brain-arteriosclerosis, senile dementia, organ-arteriosclerosis and the so called generalized arteriosclerosis.

---

Résumé Présentation de méthodes cliniques, histopathologiques et neuropathologiques destinées à la détermination qualitative et quantitative de modifications artérioscléreuses. La base est fournie par des recherches sur l'oeil, le cerveau, le rein, les coronaires, l'aorte et les grands vaisseaux du corps (125 cas). On discute de la valeur diagnostique des altérations des vaisseaux rétiniens dans l'artériosclérose cérébrale, la démence sénile, l'artériosclérose des organes et l'artériosclérose dite généralisée.

---

---

Universitfits-Augenklinik.     

A curious affection of the Fundus oculi: Helicoid peripapillar chorioretinal degeneration. Its relation to pigmentary paravenous chorioretinal degeneration

Summary Under the name of helicoid peripapillar chorioretinal degeneration the author describes a case of this curious affection of which exist a congenital and stationary form and a progressive adult form illustrated by this personal observation.The possible relation of this degenerative affection to inflammatory conditions is discussed. From a diagnostic point of view, it is noted that the radial atrophic zones are not related to the retinal vessels, contrary to the pigmentary paravenous retinochoroidal degeneration where the atropic zones always follow the retinal vesselsFinally some affections which can also be accompanied by peripapillar and radial atrophic zones are mentioned.

---

Zusammenfassung Unter dem Namen Degeneratio chorio-retinica peripapillaris helicoïdalis wird ein Fall einer merkwürdigen Affektion beschrieben, von der man in der Literatur einige congenitale und stationäre Fälle findet. Bisweilen tritt, in Analogie zu der hier erwähnten Beobachtung, die Degeneration erst beim Erwachsenen auf und scheint dann progressiv zu sein.Die Möglichkeit des Zusammenhanges mit entzündlichen Zuständen wird diskutiert. Differential-diagnostisch wird darauf hingewiesen, dass die radiären atrophischen Herde keinerlei Beziehungen zu den Netzhautgefässen aufweisen, im Gegensatz zu der Degeneratioretino-chorioidalis paravenosa pigmentosa, bei der die atrophischen Zonen den Netzhautgefässen folgen.Zum Schluss werden weitere Fundusaffektionen zitiert, bei denen gelegentlich ebenfalls peripapilläre und radiäre Atrophien auftreten können.

---

Résumé Sous le nom de dégénérescence choriorétinienne péripapillaire hélicoïdale l'auteur décrit une observation personnelle, de cette curieuse affection dont on connaît quelques cas congénitaux stationnaires, alors que dans d'autres cas, comme celui décrit dans ce travail, l'affection dégénérative se manifeste chez l'adulte et est alors progressive.La possibilité que des images semblables soient en rapport avec des états inflammatoires est discutée: du point de vue diagnostic on souligne que les zones atrophiques radiaires n'ont aucun rapport avec les vaisseaux rétiniens contrairement à la dégénérescence rétino-choroïdienne pigmentée paraveineuse, où les zones atrophiques suivent toujours les vaisseaux rétiniens.Pour terminer, on cite quelques affections qui peuvent également s'accompagner de zones atrophiques péripapillaires et radiaires.

---

---

Presented before the Swiss Ophthalmological Society, Lugano, October 6–8, 1961.

---

Unfortunately, Prof. A. RumNo, as well as Dr. E. I:?REGNAN of the Ophthalmological Clinic of Padua, have not been able to find the new address of the patient.

---

University Eye Clinic     

The UK National Artificial Eye Questionnaire study: predictors of artificial eye wearers’ experience part 1—comfort and satisfaction

ObjectivesTo report associations with comfort and with appearance satisfaction in artificial eye wearers.MethodsMulticentre, observational, cross-sectional study, nationwide within the National Health Service England. The National Artificial Eye Questionnaire (NAEQ) was completed by 951 respondents. Multiple regressions assessed associations between the experiences of artificial eye wearers, routine management, changes over time, baseline and demographic parameters and their reported comfort, satisfaction with appearance and prosthesis motility.ResultsBetter comfort levels were associated with needing less lubrication (β = 0.24, p < 0.001), older age (β = 0.17, p = 0.014), less discharge (β = 0.16, p < 0.001), less frequent cleaning (β = 0.16, p = 0.043), and male gender (β = 0.06, p = 0.047). Greater satisfaction with the appearance of the artificial eye was associated with better perceived motility (β = 0.57, p < 0.001). Black ethnic origin predicted a lower satisfaction with the appearance (β = −0.17, p = 0.001). Greater satisfaction with the motility was associated with a better appearance rating (β = 0.51, p < 0.001), longer time of having an artificial eye (β = 0.13, p < 0.001), older age (β = 0.11, p = 0.042), and a shorter adjustment time (β = −0.07, p = 0.016). Of the testimonials concerning appearance aspects, the majority (21/45, 46.7%) were related to the effect on social interactions.ConclusionsThe results suggest that more attention should be given to the “dry anophthalmic socket syndrome” as a key cause of discomfort. Young patients are concerned particularly about the motility of the artificial eye. Over time satisfaction with the artificial eye movement is likely to improve.Subject terms: Quality of life, Signs and symptoms     

Retinal nerve fibre layer polarimetry: histological and clinical comparison

AIMS—To compare histological thickness of the retinal nerve fibre layer in the primate with retardation measurements obtained in vivo using the Mark II Nerve Fiber Analyzer (NFA, Laser Diagnostic Technologies, San Diego, USA).
METHODS—Scanning laser polarimetry was performed on both eyes of a healthy anaesthetised adult primate (Macaca mulatta). The retinal nerve fibre layer thickness was measured in the eye with the best polarimetry image. A nerve fibre layer thickness map was scaled and aligned to a retardation map to permit correlation of retardation and thickness measurements.
RESULTS—Retinal nerve fibre layer thickness measurements could be satisfactorily aligned with corresponding retardation values at 216 locations. The overall correlation coefficient for nerve fibre layer thickness and retardation was r = 0.70 (n = 216, p <0.001). Regional comparison showed the best correlation (r = 0.76, n = 45, p <0.001) occurred inferior to the optic disc. Less positive but still highly significant correlations were seen superiorly and temporally (r = 0.52, n = 26, p = 0.007 and r = 0.49, n = 86, p = <0.001 respectively), with the lowest correlation occurring at the nasal aspect of the disc (r  = 0.06, n  = 67, p = 0.64).
CONCLUSIONS—In the primate eye, retinal nerve fibre layer thickness shows a positive correlation with retardation measurements obtained with the nerve fibre analyser. However, since the correlation coefficient varied around the optic disc, further evaluation of the device is advised before its routine clinical use.

Keywords: nerve fibre layer; polarimetry; glaucoma; optic disc     

The utility of anterior segment optical coherence tomography angiography for the assessment of limbal stem cell deficiency

PurposeTo determine the utility of anterior segment optical coherence tomography angiography (AS-OCTA) in assessing limbal stem cell deficiency (LSCD).MethodsTwenty-six eyes of 24 LSCD patients, classified clinically into stage I, II and III, and 12 eyes of 12 healthy subjects were included. AS-OCTA images were analyzed by two masked observers, measuring the maximum corneal vascular extension (CoVE) from the limbus to the furthest vessel over the cornea, and corneal vascular thickness (CoVT) from the most superficial to the deepest corneal vessel.ResultsCoVE was 0.27 ± 0.10, 0.79 ± 0.21, 1.68 ± 0.89 and 2.53 ± 0.82 mm in controls, stage I, II and III LSCD, respectively (p < 0.001). The CoVT was 51.0 ± 19.4, 113.7 ± 36.6, 129.7 ± 39.3 and 336.0 ± 85.0 μm, respectively (p < 0.001). There was a significant difference in CoVE and CoVT between all stages compared to controls, and between stage I and III LSCD (p < 0.001). Further, CoVE showed a significant difference between stage I and II, whereas CoVT showed a significant difference between stage II and III LSCD (p < 0.001). BCVA showed strong correlation with CoVT (r = 0.765, p < 0.001) and moderate correlation with CoVE (r = 0.547, p = 0.001). AS-OCTA parameters showed excellent intra- and inter-class correlation coefficients (>0.900).ConclusionLSCD demonstrates significant changes in CoVE and CoVT as early as stage I LSCD in comparison to controls. CoVE and CoVT strongly correlate to both disease severity and BCVA. AS-OCTA may provide novel quantitative and non-invasive parameters to assess LSCD.     

Axial length as a basic anatomical predictor for morphological and clinical characteristics in acute central serous chorioretinopathy

ObjectivesTo study the association between axial length (AL) and morphological and clinical characteristics in acute central serous chorioretinopathy.MethodsAll patients received optical coherence tomography, fluorescein angiography (FA), optical biometry, and retro-mode scanning laser ophthalmoscopy. The distance between the leakage point and the centre of the fovea were defined using FA images, and its correlation with AL, subfoveal choroidal thickness (SCT), central retinal thickness (CRT), and neurosensory detachment (NSD) area was calculated. The number of leaks, rate of bilateral involvement, and recurrence rate was evaluated.ResultsForty-seven patients (47 eyes) were included in this study (38 males, 9 females, mean age 43.5 ± 10.8 years). The distance between the leakage point and the centre of the fovea had a correlation with AL (r = −0.38, p = 0.008), SCT (r = 0.51, p = 0.0004), and the area of NSD (r = 0.5, p = 0.0006) but not with CRT (r = −0.11, p = 0.45). A statistically significant difference in the distance between the leakage point and the centre of the fovea was found between eyes with short (<23.0 mm), medium (23.0–24.0 mm), and long (>24.0 mm) AL (p = 0.014). Number of leaks, rate of bilateral involvement, and recurrence rate had a negative linear association with AL (p < 0.05).ConclusionsAL appears to be the basic anatomical predictor, which associated with morphological and clinical characteristics in acute central serous chorioretinopathy.Subject terms: Retinal diseases, Predictive markers     

Individual set-point and gain of emmetropization in chickens

During the developmental process of emmetropization evidence shows that visual feedback guides the eye as it approaches a refractive state close to zero, or slightly hyperopic. How this “set-point” is internally defined, in the presence of continuous shifts of the focal plane with different viewing distances and accommodation, remains unclear. Minimizing defocus blur over time should produce similar end-point refractions in different individuals. However, we found that individual chickens display considerable variability in their set-point refractive states, despite that they all had the same visual experience. This variability is not random since the refractions in both eyes were highly correlated - even though it is known that they can emmetropize independently. Furthermore, if chicks underwent a period of experimentally induced ametropia, they returned to their individual set-point refractions during recovery (correlation of the refractions before treatment versus after recovery: n = 19 chicks, 38 eyes, left eyes: slope 1.01, R = 0.860; right eyes: slope 0.85, R = 0.610, p < 0.001, linear regression). Also, the induced deprivation myopia was correlated in both eyes (n = 18 chicks, 36 eyes, p < 0.01, orthogonal regression). If chicks were treated with spectacle lenses, the compensatory changes in refraction were, on average, appropriate but individual chicks displayed variable responses. Again, the refractions of both eyes remained correlated (negative lenses, n = 18 chicks, 36 eyes, slope 0.89, R = 0.504, p < 0.01, positive lenses: n = 21 chicks, 42 eyes, slope 1.14, R = 0.791, p < 0.001). The amount of deprivation myopia that developed in two successive treatment cycles, with an intermittent period of recovery, was not correlated; only vitreous chamber growth was almost significantly correlated in both cycles (n = 7 chicks, 14 eyes; p < 0.05). The amounts of ametropia and vitreous chamber changes induced in two successive cycles of treatment, first with lenses and then with diffusers, were also not correlated, suggesting that the “gains of lens compensation” are different from those in deprivation myopia. In summary, (1) there appears to be an endogenous, possibly genetic, definition of the set-point of emmetropization in each individual, which is similar in both eyes, (2) visual conditions that induce ametropia produce variable changes in refractions, with high correlations between both eyes, (3) overall, the “gain of emmetropization” appears only weakly controlled by endogenous factors.     

基于GMPE模块OCT与眼底彩色照相法测量客观眼球旋转度的比较

目的：比较基于GMPE模块光学相干断层扫描(OCT)与传统眼底彩色照相法(FCP)测量客观眼球旋转度的一致性和可行性。

方法：纳入2020-12/2021-03我院斜弱视门诊受检者,同一天用基于GMPE模块OCT与FCP两种方法测量客观眼球旋转度。FCP使用Adobe Photoshop软件手动定位测量黄斑中心凹-视盘中心夹角度数(FDA),基于GMPE模块OCT软件自动定位黄斑和视盘中心测量FDA。

结果：纳入55例受检者,OCT测量FDA分别为右-6.6°±4.5°和左-8.8°±4.7°,FCP测量FDA分别为右-6.6°±4.7°和左-8.4°±4.1°,两种方法测量结果无差异(P_右眼=0.90,P_左眼=0.08)。外斜视患者OCT测量FDA分别为右-5.8°±4.9°和左-9.1°±4.5°,FCP测量FDA分别为右-5.7°±5.0°和左-8.6°±4.3°(P_右眼=0.75,P_左眼=0.15)。类似地,内斜视患者OCT测量FDA分别为右-9.0°±7.3°和左-11.3°±3.5°,而FCP测量FDA分别为右-10.0°±7.0°和左-10.1°±2.8°(P_右眼=0.21,P_左眼=0.10),两种测量方法在内外斜视患者中均无差异(P>0.05)。Pearson检验及Bland-Altman分析两种方法的结果高度相关一致(r_右眼=0.93,r_左眼=0.94,均P<0.01)。

结论：基于GMPE模块OCT可用于客观眼球旋转度的测量,且可信度及重复度高,临床有望替代眼底彩色照相法。     

Pattern electroretinogram changes after intravitreal bevacizumab injection for diabetic macular edema

We aimed at investigating the efficacy of intravitreal bevacizumab injection by evaluation of pattern electroretinogram (PERG) in diabetic patients with clinically significant macular edema (CSME). Thirty-five eyes of 35 patients with diabetes were treated with 2.5 mg of intravitreal bevacizumab injection as the primary therapy for CSME. The main outcome measures included best-corrected visual acuity, fundus fluorescein angiography, and P₅₀ amplitudes of pattern electroretinogram (PERG) before and after intravitreal injection. Mean visual acuity improved significantly from a mean LogMAR value of 1.1 ± 0.2 at baseline to a maximum of 0.7 ± 0.3 after a mean follow-up time of 6.4 months. The mean baseline P₅₀ and N₉₅ amplitudes of PERG before intravitreal injection were 1.4 ± 0.7 and 2.4 ± 0.8 μV, respectively. After the treatment, the mean P₅₀ amplitude of PERG was 2.4 ± 0.9 μV at 1-month, 2.3 ± 0.8 μV at 3-month, and 2.2 ± 0.8 μV at the last visit, and the mean N₉₅ amplitude of PERG was 3.4 ± 1.05 μV at 1-month, 3.3 ± 0.9 μV at 3-month, and 3.2 ± 0.9 μV at the last visit, and the mean P₅₀ and N₉₅ amplitudes were significantly higher when compared with baseline values (for each, P < .001). Mild anterior chamber inflammation in four eyes was controlled with topical corticosteroids. Eyes with diabetic macular edema treated with intravitreal bevacizumab showed improvement in visual acuity that was accompanied by improvement in PERG amplitudes. Further randomized trials are needed to investigate the role of PERG measurements in the evaluation of the efficacy of intravitreal bevacizumab injection.     

Anterior-posterior asymmetry in iris mechanics measured by indentation

Indentation and histological analysis of the porcine iris were done to assess the relative stiffness of the anterior (stroma) and posterior (dilator and sphincter) layers. The dimensions of the constituent structures were documented histologically by staining with a monoclonal anti-human α-smooth muscle actin antibody to determine the location of the stroma, sphincter, and dilator. Intact porcine irides (4–8 h post-mortem) were bisected into two equal C-shaped halves to indent both surfaces. Indentation experiments were performed using a 1 mm cylindrical indenter tip. The load–displacement curve for each experiment was used to estimate effective instantaneous and equilibrium moduli for the anterior and posterior surfaces of the tissue. A total of 18 irides (9 pairs) with 3–5 indentations per iris surface was performed. The average thickness of the samples was 550 μm; the indentation depth was limited to 60–100 μm depending on the thickness of the sample at each point. Posterior surface indentation gave larger forces than anterior, with the resulting instantaneous modulus of 6.0 ± 0.6 kPa versus 4.0 ± 0.5 kPa (mean ± 95% CI, n = 45, p < 0.001) and equilibrium modulus of 4.4 ± 0.9 versus 2.3 ± 0.3 (p = 0.007). The stress–relaxation analysis revealed that the anterior surface had a shorter relaxation time (121.31 ± 6.84 s) than the posterior surface (210.61 ± 9.41 s, p = 0.03), perhaps due to the permeability of the stroma. Recognizing that our effective modulus calculations in this study did not account for heterogeneity, viscoelasticity, or poroelasticity, we conclude that the posterior components of the iris – dilator, pigment epithelium, and sphincter – are on average stiffer than the stroma and anterior border layer.     

Some experience of clinical flicker electroretinography

Summary Flicker-electroretinographic examinations were made in 180 patients (238 eyes) with various eye diseases, comprising 22 diagnostic groups in all. The largest groups were detachment of the retina and diabetic retinopathy. An account is given of some of the groups.In detachment of the retina, cases with relatively well-preserved flicker fusion frequency (FFF) had a more favorable prognosis from the operative point of view than others. In diabetic retinopathy, the proliferative type was associated with the poorest FFF, the exsudative type being the next in order, whereas the haemorrhagic type had unimpaired FFF. In senile macular degeneration in the majority of cases the FFF was decreased in the photopic region. In detachment of the choroid, the FFF was normal when detachment was of short duration, and reduced with longer duration. It is conceivable that flicker electroretinography, as a complement to clinical single-flash ERG, may prove to be a valuable diagnostic tool.

---

Zusammenfassung Das Flimmer ERG ist in 180 Patienten (238 Augen) mit verschiedenen Augenleiden, die zu 22 diagnostischen Gruppen gehören, registriert worden.Die Hauptgruppen waren: Netzhautablösung, diabetische Retinopathie, seniler Cataract, Kreislaufstörungen der Netzhaut und Retinitis pigmentosa.Die Resultate der einzelnen Gruppen werden besprochen. Es stellte sich heraus, dass in den Fällen von Netzhautablösung, die eine relativ normale Flimmerfusionsfrequenz (FFF) aufweisen, eine günstige Prognose zur Operation vorlag.In der diabetischen Retinopathie war die Retinitis proliferans assoziiert mit einer sehr niedrigen FFF. Der exsudative Typus hat eine etwas höhere FFF und der haemorrhagische Typus ist mit einer normalen FFF verbunden.In den meisten Fällen von seniler Maculadegeneration war die FFF erniedrigt. In Solutio chorioideae war die FFF normal wenn die Ablösung frisch war, und erniedrigt wenn die Ablösung älter geworden war.Es ist wahrscheinlich, dass Flimmerelektroretinographie eine wertvolle Ergänzung des Einzel-Blitz-ERGs ist.

---

Résumé Le flicker ERG a été enregistré dans 180 malades (238 yeux) avec des affections oculaires divisées en 22 groupes diagnostiques.Les groupes principaux étaient: décollement de la rétine, rétinopathie diabétique, cataracte sénile, troubles de la circulation rétinienne et rétinopathie pigmentaire. Quelques groupes sont considérés en détails.Dans le décollement de la rétine, les cas montrant une fréquence critique de fusion du flicker (FCF) relativement intact étaient prognostiquement les plus favorables. Dans la rétinopathie diabétique le type proliférant était associé avec une FCF très basse; le type exsudatif était associé avec une FCF un peu plus élevée, alors que le type hémorragique montrait une FCF intacte. Dans la dégénérescence maculaire sénile la FCF dans la région photopique était réduite, dans la majorité des cas. Dans le décollement de la choroide la FCF était normale quand le décollement était d'une durée brève, et subnormale quand la durée était prolongée. Il est très probable que dans la clinique la flicker électrorétinographie sera un supplément précieux du ERG enregistré après stimulation avec des éclairs singuliers.

---

---

Eye Clinic, Karolinska Sjukhuset.     

Widefield topographical analysis of the retinal perfusion and neuroretinal thickness in healthy eyes: a pilot study

PurposeIn this pilot study we reported variation of superficial (SCP) and deep (DCP) capillary plexuses flow in macular and near/mid periphery regions in healthy subjects using widefield swept source-optical coherence tomography angiography (SS-OCTA).MethodsIn this prospective, cross-sectional study, enroled subjects were imaged with an SS-OCTA system (PLEX Elite 9000, Carl Zeiss Meditec Inc., Dublin, CA, USA). OCTA scans were taken in primary and extremes of gaze and a montage was automatically created. Quantitative analysis was performed in the macular and peripheral regions. In addition, SCP and DCP variables were further investigated in distinct fields within these three different regions.ResultsFifty-five young healthy subjects (55 eyes) were enroled. The retinal periphery displayed a higher SCP perfusion density (39.6 ± 1.7% and 40.7 ± 1.4%, P < 0.0001) and SCP vessel diameter index (3.5 ± 0.2 and 3.6 ± 0.2, P < 0.0001), in comparison with the macular region. At the DCP level, the retinal periphery was characterized by a lower perfusion density (41.6 ± 3.7% and 37.9 ± 2.9%, P < 0.0001) and vessel length density (14.6 ± 6.0% and 9.9 ± 2.6%, P < 0.0001). In the analysis investigating the DCP in the retinal periphery, the temporal sector was characterized by a reduction in perfusion density, vessel length density, and vessel diameter index. In univariate analysis, the retinal thickness was found to have a significant direct relationship with DCP perfusion density (P < 0.0001), but not with SCP perfusion density (P = 0.712).ConclusionsWe report quantitative mapping of the SCP and DCP in healthy individuals. The DCP perfusion appears to have a wide topographical variation, which is strictly dependent on the retinal thickness.Subject terms: Scientific community, Cell biology     

Frequency characteristics of accommodation in a patient with agenesis of the posterior vermis and normal subjects

AIMS—To clarify the cerebellar control of accommodation in humans, the frequency characteristics of accommodation were studied in a patient with agenesis of the posterior cerebellar vermis and four age matched normal subjects.
METHODS—Magnetic resonance imaging of the brain of the 29 year old patient showed agenesis of the vermis and paravermis of lobules VIII-X and hypoplasia of the vermis and paravermis of lobules I-VII, the cerebellar hemisphere, and the cerebellar nuclei. The gain and phase lag of accommodative responses for sinusoidally modulated blur stimuli were calculated for the patient and four normal subjects. The blur stimuli consisted of predictable simple sinusoids of 3.0 dioptres at a frequency of 0.05, 0.1, 0.2, 0.3, 0.5, or 1.0 Hz.
RESULTS—The frequency characteristics of accommodative responses in the patient have a larger phase lag and a smaller gain at higher frequencies than those in the four normal subjects.
CONCLUSIONS—These findings suggest that the cerebellum contributes to the control of accommodation by improving the frequency characteristics at high frequencies.

     

Optical coherence tomography angiography characteristics of choroidal melanoma

PurposeThe purpose of this study is to evaluate tumour vasculature with optical coherence tomography angiography (OCTA) in malignant choroidal melanoma (CM).Materials and methodsPatients with unilateral CM were included in this cross-sectional observational clinical study. Applying OCTA systems operating at 840-nm wavelengths, eyes with CM were imaged. The primary main outcome measures were OCTA images, qualitative evaluation of macular and tumour vasculature, quantitative vascular density (VD), perfusion density (PD) and the foveal avascular zone disruption.ResultsThe study included 11 patients with unilateral CM and contralateral unaffected eyes as the control group. Eyes of 11 patients with CM and contralateral unaffected eyes were imaged before brachytherapy and 5 patients were imaged post brachytherapy. CM is demonstrated dense, tortuous blood vessels, uneven thickness and relatively disorganised intratumoural vasculature. In 11 eyes with CM, the VD and PD in the macular area were significantly lower within affected eyes (131.333 ± 27.807%, 3.152 ± 0.714%, p < 0.0001) than in contralateral eyes (154.208 ± 5.599%, 3.662 ± 0.127%, p < 0.0001). The VD and PD in the tumour area (67.990 ± 34.899%, 1.617 ± 0.847%, p < 0.0001) were significantly lower when compared to the macular area of affected eyes (131.333 ± 27.807%, 3.152 ± 0.714%, p < 0.0001) and the macular area of contralateral eyes (154.208 ± 5.599%, 3.662 ± 0.127%, p < 0.0001). After radiation treatment, the VD and PD in five CM eyes (116.526 ± 7.598%, 2.438 ± 0.358%, p < 0.05) were significantly lower than before treatment (141.544 ± 14.645%, 3.327 ± 0.354%, p < 0.05). Tumour regression after radiation therapy for melanomas was associated with decreased vessel density.ConclusionsOCTA can provide a dye-free, non-invasive, reliable method to monitor a variety of tumours, including CM for growth and vascularity. Upon OCTA, this could be helpful in evaluating the variety of tumour blood vessels before and after brachytherapy to judge the curative effect and whether the tumour recurred. Detection of the characteristic vascular features of CM by OCTA could make OCTA an assuring diagnostic modality to differentiate malignant lesions.Subject terms: Prognosis, Cancer     

The electroretinographic response to weak stimuli of large subtense

Summary If a stimulus of large subtense and low intensity, e.g. 100 times above the absolute visual threshold, is presented to the dark adapted eye, the resulting ERG-response shows several fast positive components, followed by a slow negative deflection.The number of the positive components depends mainly on the duration of the flash. The first component is hardly affected by changes in the intensity of the flash; the second and following ones show, within the intensity range studied, a linear dependency and the latter therefore determine the amplitude and shape of what is called the normal scotopic b-wave.This linearity also accounts for the excellent responses one can obtain at intensity levels very near the differential visual threshold. Apart from the way light adaptation affects the several components we have also devoted attention to the response on a dark flash and to the influence exerted by dark adaptation and the subtense of the stimulus field.

---

Zusammenfassung Ein schwacher Lichtreiz, z.B. einhundert Mal über der absoluten Wahrnehmungsschwelle, führt zu einer electroretinographischen Antwort, die mehrere positive Komponenten zeigt, deren Zahl von der Dauer des Reizes abhängt. Sie werden von einer negativen Potentialschwankung gefolgt. Die erste positive Komponente ist relativ unabhängig von Intensitäts-Variationen; die zweite und die folgenden sind jedoch in dem studierten Bereich linear intensitäts-abhängig und bestimmen demgemäß die Höhe und Form der scotopischen b-Welle. Es läßt sich aus dieser linearen Abhängigkeit auch die Tatsache erklären, daß Lichtreize auf einem Hintergrund dargeboten, sogar wenn sie kaum mehr sichtbar sind, noch hohe Antworten geben.Die Untersuchung befaßt sich weiter mit dem Einfluß, den die Dunkel-adaptation und die Größe des Reizfeldes auf die Komponenten ausüben und mit der Antwort auf Dunkelblitze.

---

Résumé Un éclair assez faible ne dépassant pas par exemple cent fois le seuil visuel absolu et présenté au champ visuel entier, donne une réponse électrorétino-grafique montrant plusieurs composantes positives. Le nombre de ces composantes dépend de la durée de l'éclair. L'amplitude de la première composante est pratiquement indépendante de la luminance de l'éclair. L'amplitude des composantes suivantes dépend d'une façon linéaire de la luminance.C'est grâce à cette linéarité que l'amplitude d'une réponse à un éclair présenté sur un fond lumineux n'est pas diminuée; ainsi il est possible d'obtenir des réponses assez larges aux éclairs qui sont seulement deux ou trois fois au-dessus du seuil visuel différentiel.Enfin on a étudié l'influence de l'adaptation à l'obscurité et de la surface du champ visuel présenté sur les différentes composantes, ainsi que la réponse aux éclairs, dits négatifs.

---

---

Institute for Perception RVO-TNO, Soesterberg, The Netherlands.     

Decay of suppression of retinal function after short flashes of light — Electroretinographic measurements in the dark adapted human eye

Summary When the dark adapted human eye is stimulated with pairs of single flashes of light of 5 lux intensity and 125 msec duration, the difference in size of the b-waves of the two ERGs evoked, as related to the dark interval between the stimuli, indicates exponential decay of the suppression caused by the first stimulus.When a flickering light of constant one-to-five light/dark ratio is used for stimulation and the difference in size between the first b-wave and the constant amplitude of the flicker ERG is related to the dark interval between the flickering stimuli, the exponential formula of decay of suppression is not strictly obeyed.It is concluded that the constant amplitude response of the flicker ERG or the amplitude of the second b-wave evoked by a pair of flashes, depends both on the duration of the light stimuli and the duration of the dark interval between the stimuli.A quantitative method is suggested of using pairs of single flashes for stimulation in clinical electroretinography.

---

Zusammenfassung Wenn das dunkeladaptierte menschliche Auge durch Doppelreize mit einer Intensität von 5 Lux und einer Dauer von 125 msek. gereizt wird, so stellt sich heraus, dass der Höhenunterschied der b-Welle dieser beiden ERGs zusammenhängt mit der Dunkelperiode zwischen den beiden Reizen, und zwar einen exponentiellen Ablauf der Suppression, verursacht vom ersten Reiz, darbietet.Wenn Flimmerreize von Licht/Dunkelverhältnis 1 auf 5 benutzt werden, dann wird diese Gesetzmässigkeit - wenn man das Verhältnis zwischen der ersten b-Welle und der konstanten Amplitude des Flimmer-RG's, und der Dunkelperiode zwischen den Flimmerreizen betrachtetnicht ganz erfühlt.Es wird gefolgert, dass die Höhe der zweiten b-Welle bei der Reizung durch Doppelreize und die Höhe der konstanten Amplitude des Flimmer-ERGs bei Flimmerreizung abhängig sind von der Dauer der Lichtreize und der Dunkelperiode zwischen den Lichtreizen.

---

Résumé Quand on applique la stimulation lumineuse dans l'adaptation à l'obscurité avec des éclairs couplés d'une intensité de 5 Lux et d'une durée de 125 msec, la différence d'amplitude des ondes-b de ces deux ERGs consi dérée en relation avec l'intervalle d'obscurité entre les éclairs, indique une régression exponentielle de la suppression de la deuxième onde produite par le premier stimulus.Quand on utilise une stimulation lumineuse intermittente d'un rapport lumière/obscurité d'un sur cinque, la différence d'amplitude de la première onde-b et l'amplitude constante du flicker ERG en relation de la période d'obscurité entre les éclairs intermittents, la formule de la régression exponentielle de la suppression n'est pas suivie strictement.La conclusion est faite que l'amplitude constante du flicker ERG, ou l'amplitude de la seconde onde-b dépend aussi bien de la durée des éclairs que de la durée d'intervalle entre les éclairs.L'auteur propose d'utiliser des éclairs couplés dans l'électrorétinographie clinique.

---

---

This investigation was supported by a grant from the Sigrid Juselius Stiftelse.

---

Department of Ophthalmology, University Central Hospital.     

Effect of intravitreal plasmin on vitreous removal through a 25-gauge cutting system in the rabbit in vivo

Purpose  Intravitreal plasmin creates a posterior vitreous detachment, but may also liquefy the vitreous. This study measures the rate of vitreous removal from rabbit eyes after plasmin injection in vivo. Methods  Intravitreal injections of 150 IU hyaluronidase (n = 5), 0.5 activity units (AU, n = 6) or 0.9 AU of streptokinase-activated human plasmin (n = four groups of 6) in 0.1 ml were performed in rabbits, the fellow eyes received 0.1 ml BSS. After 30 min (hyaluronidase), 30 min, 4 h, 12 h or 24 h (0.9 AU plasmin) or 24 h (0.5 AU plasmin), 1 ml of vitreous was removed from each eye without infusion, using a 25-gauge cutter and a standardized protocol. Animals were sacrificed after surgery. Results  Compared to fellow eyes, the average rate of vitreous removal was increased by hyaluronidase by 68.9 ± 6.3% (p < 0.05) and by 0.5 AU plasmin (24 h) by 26.8 ± 3.3% (p < 0.05). 0.9 AU of plasmin increased removal rates by 0.8 ± 10% (n.s.), 15.4 ± 6.3% (p < 0.05), 40.3 ± 3.1% (p < 0.05), and 71.9 ± 32.4% (p < 0.05) after 30 min, 4 h, 12 h and 24 h incubation respectively. The ratios of removal rates of treated/control eyes in the 0.9 AU groups showed a linear correlation with incubation time (r = 0.783, p < 0.0001). Conclusion  Intravitreal plasmin increases the rate of vitreous removal in rabbits. This work was presented in part at the 76th Annual Meeting of the Association for Research in Vision and Ophthalmology, 2004. Supported in part by grants from the University of Aachen, Germany and the Deutsche Forschungsgemeinschaft (HE 3503/1-1) to M. Hermel, and by NuVue Technologies, Keene, New Hampshire, USA. W. Dailey and M. Hartzer have a proprietary interest in plasmin.     

Increased level of (1,3)-β-D-glucan in tear fluid of mycotic keratitis

Purpose  Increased concentration of (1,3)-β-D-glucan, one of the major components of fungal cell walls, is detected in the serum of systemic fungal infection. In our study, the concentration of (1,3)-β-D-glucan was measured in the tear fluid of patients with mycotic keratitis. Methods  Tear fluid was collected from patients with fungal keratitis (n = 4) and bacterial corneal ulcers (n = 4) with or without corneal scraping. In addition, tear fluid was collected from patients without corneal diseases. Results  The concentration of (1,3)-β-D-glucan in tear fluid collected without corneal scraping was 4.0 ± 3.5, 5.8 ± 2.6, 184 ± 128 pg/ml in the control, bacterial corneal ulcer, and mycotic keratitis samples respectively. The concentration of (1,3)-β-D-glucan in tear fluid collected after scraping the corneal lesions with a tip of glass capillary was 4.4 ± 1.3, 8.2 ± 5.2 and >1,000 pg/ml in the control, bacterial ulcer, and mycotic keratitis samples respectively. Conclusions  A significant increase in (1,3)-β-D-glucan was detected in tear samples from patients with mycotic keratitis. Measuring the concentration of (1,3)-β-D-glucan in tear fluid might be helpful in the diagnosis of mycotic keratitis. Financial Interest: None