2024-06-28, Joss, Joëlle, Jainta, Stephanie

Purpose. Asthenopic symptoms mostly occur during demanding near-sighted tasks and are related to binocular symptoms (e.g. heterophoria), among others. Correction of symptomatic heterophoria with prismatic glasses is one way to treat the symptoms. This study investigates the effect of wearing a horizontal prismatic correction for 6 months. Material and Methods. A total of 87 subjects were assigned to a heterophoric prism group (N=32), a heterophoric control group (N= 31) or an orthophoric control group (N= 24) according to their MCH heterophoria. In the heterophoric prism group, the subjects were prescribed glasses with a prismatic correction for 6 months according to their distance correction; in contrast, the subjects in the heterophoric control group had to wear glasses without prismatic correction for the same period. The effect of the prisms on complaints due to asthenopic symptoms was investigated by comparing the total sum obtained in the CISS questionnaire at the beginning of the study and after 6 months (before and after wearing glasses) for the 3 groups. Results. A (long-term) prism effect was not apparent in the CISS total score. In both the heterophoric prism group and in the heterophoric control group, the CISS total score increased slightly and non-significantly after 6 months. When considering the heterophoric subjects with an increased CISS score at baseline, a nevertheless slight but non-significant decrease of symptoms was observed. All changes were observed in both the heterophoric prism group and the heterophoric control group. An additional analysis using binocular profiles showed a reduction in symptoms by numbers and specifically for subjects with reduced vergence facility. Conclusion. Wearing an individual, horizontal prismatic correction had no effect on the overall CISS-score for our test subjects. Further methods that allow a systematic recording of symptoms and optometric parameters are probably necessary to observe an effect. These could be binocular profiles that classify individuals according to their binocular parameters.

2022, Joss, Joëlle, Jainta, Stephanie

Zweck. Beim Lesen mit beiden Augen stellt sich ein binokularer Vorteil (kürzere Lese- und Fixationszeiten im Vergleich zu monokularem Lesen), welcher durch Prozesse der motorischen und sensorischen Fusion zustande kommt, ein. Der binokulare Vorteil beim Lesen ist zum Teil von der individuellen horizontalen Heterophorie abhängig und damit stellte sich die Frage, ob sich prismatische Korrektionen (bestimmt nach der MKH-Methode, zum Ausgleich einer Heterophorie) auf den binokularen Vorteil oder auf Parameter der binokularen Koordination beim Lesen auswirken. Material und Methoden. Wir haben die binokularen Augenbewegungen von 54 Personen mit einer individuellen horizontalen Heterophorie beim Lesen vermessen (Eyelink II): für (1) monokular, (2) binokular, (3) binokular mit Disparität (entsprechend MKH-Prisma) und (4) binokular mit Disparität nach sechs Monaten präsentierte, deutschsprachige Sätze (insg. 120). In der sechsmonatigen Pause zwischen Messung (3) und (4) trugen 29 Personen Brillen mit prismatischen Korrektionen, während 25 Personen als Kontrollgruppe fungierten. Ergebnisse. Unsere Daten zeigten einen klaren, signifikantenVorteil für binokulares Lesen für alle Personen, ohne dass eine kurzfristige Präsentation einer individuellen Disparität (analog eines MKH-Prismas) daran etwas änderte. Erst nach einer Prismentragezeit von sechs Monaten zeigte sich zusätzlich ein tendenziell größerer binokularer Vorteil in der „Prismengruppe“ im Vergleich zur „Kontrollgruppe“. Parallel dazu nahm die Kopplung der Augen (Diskonjunktion) leicht zu und die objektive Fixationsdisparität nahm signifikant ab. Fazit. Das Tragen einer individuellen prismatischen, horizontalen Korrektion (MKH) hatte für unsere Studienteilnehmer*innen einen Einfluss auf die binokulare Koordination beim Lesen und erhöhte gleichzeitig den binokularen Vorteil. Dieser eher mittel- bis langfristige Effekt von prismatischen Korrektionen ist neu und sollte in weiteren Studien vertieft untersucht werden.

2022-10, Joss, Joëlle, Jainta, Stephanie

2021-01-21, Joss, Joëlle, Jainta, Stephanie

In reading, binocular eye movements are required for optimal visual processing and thus, in case of asthenopia or reading problems, standard orthoptic and optometric routines check individual binocular vision by a variety of tests. The present study therefore examines the predictive value of such standard measures of heterophoria, accommodative and vergence facility, AC/A-ratio, NPC and symptoms for binocular coordination parameters during reading. Binocular eye movements were recorded (EyeLink II) for 65 volunteers during a typical reading task and linear regression analyses related all parameters of binocular coordination to all above-mentioned optometric measures: while saccade disconjugacy was weakly predicted by vergence facility (15% explained variance), vergence facility, AC/A and symptoms scores predicted vergence drift (31%). Heterophoria, vergence facility and NPC explained 31% of fixation disparity and first fixation duration showed minor relations to symptoms (18%). In sum, we found only weak to moderate relationships, with expected, selective associations: dynamic parameter related to optometric tests addressing vergence dynamics, whereas the static parameter (fixation disparity) related mainly to heterophoria. Most surprisingly, symptoms were only loosely related to vergence drift and fixation duration, reflecting associations to a dynamic aspect of binocular eye movements in reading and potentially non-specific, overall but slight reading deficiency. Thus, the efficiency of optometric tests to predict binocular coordination during reading was low – questioning a simple, straightforward extrapolation of such test results to an overlearned, complex task.

2022-08, Joss, Joëlle, Jainta, Stephanie

Asthenopic symptoms are related to heterophoria and problems of binocular vision. In a recent paper, we showed that vergence drift and fixation durations are related to symptoms (CISS-questionnaire), but optometric measures such as heterophoria, vergence or accommodative facility, AC/A-ratio or NPC did not significantly add to the explained variance of asthenopia. We re-analysed our data, in which binocular eye movements were recorded (EyeLink II) for 64 participants, and linear regression analyses related all parameters of binocular coordination (objective heterophoria, vergence drift, saccade disconjugacy, fixation disparity and fixation duration), and the above-mentioned optometric tests to 4 symptoms factors (eye comfort, reading process, image quality and fatigue), which we identified by a factor analysis of the CISS-questionnaire. Objective heterophoria and fixation duration predicted 20% of the variance in symptoms concerning the reading process (factor 2). Furthermore, fixation duration seems to be slightly, but not significantly, related to symptoms addressing fatigue (factor 4), whereas optometric tests are not significantly related to any asthenopia factor. Overall, objective measures during reading relate to asthenopic symptoms, however the lack of asthenopic symptoms prediction by daily optometric parameters is still unexplained. Therefore, further research is needed to find out suited optometric parameters to infer asthenopic symptoms.

2019-12-09, Jainta, Stephanie, Joss, Joëlle

Reading with two eyes necessitates efficient processes of binocular vision, which provide a single percept of the text. These processes come with a binocular advantage: binocular reading shows shorter average fixation durations and sentence reading times when compared to monocular reading. A couple of years ago, we showed for a small sample (N=13) that binocular advantages critically relate to the individual heterophoria (the resting state of vergence). In the present, large-scale replication we collected binocular eye movements (Eyelink II) for 94 participants who read 20 sentences monocularly and 20 sentences binocularly. Further, individual heterophorias were determined using three different optometric standards: objective eye tracking (EyeLink II at 60 cm), Maddox wing test (at 30 cm) and measures following the “Guidelines for the application of the Measuring and Correcting Methodology after H.-J. Haase” (MCH; at 6 m). Binocular eye movements showed typical pattern and we replicated (1) binocular advantages of about 25 ms for average fixation durations and (2) a reduction in binocular advantages when heterophoria increased – but only when heterophoria was identified by EyeLink II or Maddox wing measures; MCH measures of heterophoria did not affect binocular advantages in reading. For large heterophorias binocular reading even turned into a disadvantage. Implications for effect estimations and optometric testing will be discussed.