THE EFFECT OF PALPEBRAL FISSURE HEIGHT IN PRIMARY GAZE POSITION ON TEAR FILM STABILITY.

This study aimed to investigate the effect of palpebral fissure height in primary gaze position in healthy individuals on tear film stability. In this cross-sectional study, 120 subjects (60 male and female each) were enrolled and divided according to age into two groups, i.e., group 1 (aged 18-50 years) and group 2 (aged 51 and older). Palpebral fissure height on both eyes was measured in primary gaze position with a clear plastic ruler held in a central vertical position between the upper and lower lid margin, and the standard tear break-up time (TBUT) test was performed to evaluate tear film stability. Palpebral fissure height was significantly higher in younger than older subjects in all measurements on both eyes (p<0.001), and TBUT was shorter in older than in younger subjects. In all subjects included in the study, palpebral fissure height was not related to TBUT (p=0.589). However, analyzing the two age groups separately, a significant negative correlation was found between the palpebral fissure height and TBUT in both groups of younger (p<0.001) and older (p=0.009) subjects. In conclusion, an enlarged exposed ocular surface due to higher palpebral fissure height in healthy individual's primary gaze position negatively affects tear film stability expressed by TBUT.

SUBCLINICAL OPTIC NEURITIS.

Acute optic neuritis is often associated with multiple sclerosis. It is considered to be the most common ocular symptom of multiple sclerosis. In addition to acute optic neuritis, in patients with multiple sclerosis, subclinical optic neuritis is also described. It is characterized by slow progression and bilateral involvement, thus being unnoticed by the patient. The purpose of the present study was to assess vision impairment in multiple sclerosis patients without a history of acute optic neuritis, using a number of functional tests including visual field testing by Octopus 101 perimetry N1 program, contrast sensitivity testing by Pelli Robson chart, and color vision by Ishihara pseudoisochromatic plates. The study included 35 multiple sclerosis patients aged 18-50 years, without subjective signs of vision impairment and visual acuity 1.0 according to Snellen. Visual field defects were found in 28 patients. The most common defects of visual fields were retinal sensitivity depression in peripheral zone and nerve fiber bundle defect. Reduced contrast sensitivity was found in 30 (86%) patients. Study results indicated multiple sclerosis patients free from signs of optic neuritis to suffer vision function impairment, as demonstrated by Octopus perimetry and contrast sensitivity testing with Pelli Robson charts.

Post-Blink Blur Time-A Simple Test to Detect Dry Eye-Related Visual Disturbances.

Background: Dry eye disease (DED) stands out as one of the most common eye conditions encountered in clinical settings. This study aimed to determine the diagnostic ability and feasibility of post-blink blur time (PBBT) in detecting patients with DED symptoms. Methods: The study included 200 subjects, 100 with and 100 without DED symptoms defined by the Schein questionnaire, who underwent assessment of DED signs [visual acuity, PBBT, conjunctival hyperemia, lid-parallel conjunctival folds-LIPCOF, tear film break-up time-TBUT, fluorescein corneal staining, and meibum score]. Results: DED subjects had a lower PBBT than controls (p < 0.001), with subjective (6 (1-45) s vs. 8 (1-70) s) and objective (6 (2-33) s vs. 8 (2-50) s) PBBT measurements being similar between repeats. The correlations between subjective and objective PBBT measurements were significantly positive (R = 0.873, p < 0.001). Subjective PBBT was negatively related to the Schein questionnaire (R = -0.217, p = 0.002), conjunctival hyperemia (R = -0.105, p = 0.035), and corneal staining (R = -0.153, p = 0.031), while positively related to the TBUT (R = 0.382, p < 0.001) and meibum score (R = 0.106, p = 0.033). Logistic regression analysis showed DED symptoms were significantly associated with subjective PBBT (AOR 0.91, p = 0.001), TBUT (AOR 0.79, p < 0.001), meibum score (AOR 0.65, p = 0.008), LIPCOF (AOR 1.18, p = 0.002) and corneal staining (AOR 1.14, p = 0.028). Conclusions: Subjective self-reported PBBT is a reliable and non-invasive screening test for evaluating time-wise changes in visual acuity and detecting a tear film dysfunction.

Pseudovitelliform maculopathy associated with hereditary hemochromatosis.

Background: Hereditary hemochromatosis (HH) is an inherited autosomal recessive iron metabolism disorder resulting from a C282Y mutation in the HFE gene. Mutations in the HFE gene may result in iron accumulation and oxidative stress in the retina, resulting in macular degeneration. This article describes two patients with HH who were treated with erythrocytapheresis or phlebotomy, with no exposure to deferoxamine or any other chelation therapy, and who developed visual symptoms. Case Presentation: Both patients had known diagnoses of HH. Because of visual symptoms, they were referred to the ophthalmology clinic and underwent a retinal exam, multimodal imaging, and electrodiagnostic studies, which revealed structural and functional degeneration of the central macula. Fundus photography, fluorescein angiography, and fundus autofluorescence revealed changes at the level of the retinal pigment epithelium (RPE) in the central macula. In addition, optical coherence tomography revealed subfoveal accumulation of hyperreflective material at and below the RPE. Multifocal electroretinography confirmed a decreased cone response, whereas the full-field electroretinogram was unremarkable. Genetic testing ruled out Best's vitelliform macular dystrophy and the other known hereditary macular dystrophies. The patients had known diagnoses of HH, homozygous C282Y mutations in the HFE gene, and no comorbidities; thus, we presumed that HH led to the observed morphological and functional disorders of the RPE, which in turn caused structural macular changes in both patients. Conclusions: Considering the macular findings and the nature of the patients' primary illness, we believe that the accumulation of iron and photoreceptor metabolic products caused dysfunction in the RPE, which led to morphological and functional changes in the macula. Because the patients were not treated using chelating agents, we attribute the macular changes solely to iron accumulation and oxidative stress caused by the pathophysiological processes of HH. Further studies are needed to identify the plausible molecular or cellular insults underlying pseudovitelliform macular degeneration in patients with HH.

Diagnostic accuracy of non-invasive tear film break-up time assessed by the simple manual interferometric device.

AIM: To determine the diagnostic accuracy of non-invasive tear film break-up time (NIBUT) measured by the handheld lipid layer examination instrument. METHODS: 108 patients were enrolled in this cross-sectional study and divided into two groups: patients with dry eye (n = 57) categorized by the presence of dry eye symptoms obtained by Schein Questionnaire and minimally-one objective dry eye sign (tear film break-up time <10 s or corneal, conjunctival and lid margin fluorescein staining), and healthy subjects (n = 51). RESULTS: Dry eye subjects had significantly shorter NIBUT than healthy subjects (6 s vs 20 s, p < 0.001). Logistic regression analysis showed that shorter NIBUT values were excellent indicators of dry eye disease (p < 0.001), with consistency and no significant difference between measurements, even after standardizing the results for age and sex. NIBUT cut-off point to distinguish dry eye from healthy subjects was 12 s (sensitivity 90.2 %, specificity 88.5 %, PPV 92.5 %, NPV 85.2 %, LR +7.82, LR- 0.11, DOR 70.92, DE 89.6 %). Good, but lower accuracy was observed at cut-off value of 10 s (sensitivity 87.8 %, specificity 88.5 %, PPV 92.3 %, NPV 82.1 %, LR+ 7.61, LR- 0.14, DOR 55.2, DE 88.1 %). The area under the ROC curve (AUC) of 0.944 classified NIBUT as a diagnostic test with very high accuracy. CONCLUSION: This study showed a high diagnostic accuracy of NIBUT measured by the handheld lipid layer examination instrument. This simple, reliable, objective and available instrument might regularly take place in routine, standard dry eye diagnostic and can be used by almost every eye specialist.