TY - THES A1 - Breher, Katharina T1 - Visual consequences of Albinism N2 - Purpose: The purpose of this thesis is to provide a comprehensive literature review about albinism as an inherited metabolic disorder of melanin synthesis along with those related conditions impacting the visual system. As such, it addresses eye care emphasizing the visual consequences of albinism along with diagnostic and treatment options. Methods: Background knowledge about ocular development is given as well as information about etiological biochemical and genetic processes. The current classification, clinical findings and their assessment and management options are presented based on recent results of research. In conclusion, two case reports are described as examples of visual care options. Results: Melanin plays a big role in the retinal and chiasmal development. Melanin biosynthesis can be disrupted by different genes in various ways which leads to the current classification of albinism. Clinical findings include fundus hypopigmenta-tion, nystagmus, iris transillumination, photophobia, foveal hypoplasia, excessive chiasmal decussation, reduced visual acuity, high astigmatism (with-the-rule), strabismus and decreased stereopsis. Treatment options to improve visual acuity, fixation and binocularity are (tinted) prescription lenses and contact lenses, low vision aids, surgical procedures and vision therapy. Medication and supplementa-tion for increased pigmentation are currently being tested on mice. Conclusions: Albinism is caused by genetic mutations resulting in ocular and cutaneous hypopigmentation. It establishes various phenotypes that require different therapy approaches in order to improve vision and therefore quality of life. KW - albinism KW - low vision KW - genes KW - melanin KW - vision therapy Y1 - 2015 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bsz:944-opus4-1939 ER - TY - THES A1 - Breher, Katharina T1 - The effect of the optical design of multifocal contact lenses on choroidal thickness N2 - Purpose: Recent studies found a reduction of myopia progression with multifocal contact lenses, however, with yet unclear mechanism. This raises the hypothesis that the addition zones of the multifocal contact lenses induce myopic defocus on the retina, which consequentially leads to choroidal thickening and therefore inhibited eye growth. We tested the effect of the optical design of multifocal contact lenses on choroidal thickness. Methods: 18 myopic students wore four different contact lenses ((1) single-vision lens corrected for distance, (2) single-vision lens with +2.50 D full-field defocus, (3) “Multifocal center-distance” design, addition +2.50 D, (4) “Multifocal center-near” design, addition +2.50 D) for each 30 minutes on their right eye. Automated analysis of the macular choroidal thickness, vitreous chamber depth and eccentric photorefraction were performed before and after each contact lens. Results: Choroidal thickness and vitreous chamber depth showed no significant differences to baseline with none of the contact lenses. Choroidal thickness increased the most with the “Multifocal center-distance” and the full-field defocus lens, followed by the “Multifocal center-near” and the single-vision contact lens (+2.1 ± 11.1 μm, +2.0 ± 11.1 μm, +1.6 ± 11.3 μm, +0.9 ± 11.2 μm, respectively). The “Multifocal center-distance” design showed an overall more myopic refractive profile than the other lenses. Changes of vitreous chamber depth occurred in anti-phase to these of choroidal thickness. Conclusion: Multifocal contact lenses have no significant influence on choroidal thickness and after short-term wear. Therefore, it is assumed that it is not the main contributor to the protective effect of multifocal contact lenses in myopia control. N2 - Ziel: Studien haben gezeigt, dass multifokale Kontaktlinsen das Fortschreiten der Myopie reduzieren können. Jedoch ist der Mechanismus dahinter noch unbekannt. Eine Hypothese besagt, dass die Additionszonen innerhalb der Multifokallinsen myopen Defokus auf der Netzhaut erzeugen, was zu einer Zunahme der Aderhautdicke und folglich zu einem gehemmten Längenwachstum des Auges führt. Aufgrund dessen haben wir den Effekt von verschiedenen optischen Designs von Multifokallinsen auf die Aderhautdicke unterssucht. Methoden: 18 myope Studenten trugen jeweils 30 Minuten lang vier verschiedene Kontaktlinsen auf ihrem rechten Auge ((1) Einstärkenlinse mit Fernkorrektur (2) Einstärkenlinse mit +2.50 D Unterkorrektur (3) Multifokallinse mit zentraler Fernzone, Addition +2.50 D, (4) Multifokallinse mit zentraler Nahzone, Addition +2.50 D). Vor und nach jeder Tragesession wurde die makuläre Aderhautdicke der Probanden automatisch ausgewertet, sowie die Glaskörperkammertiefe gemessen. Ebenfalls wurde die periphere Refraktion für jede Linse mittels exzentrischer Photorefraktion bestimmt. Ergebnisse: Es gab keine signifikanten Änderungen der Aderhautdicke und Glaskörperkammertiefe. Die Aderhautdicke nahm am meisten mit der Fern-Multifokallinse und der unterkorrigierten Einstärkenlinse zu, gefolgt von der Nah-Multifokallinse und der fernkorrigierten Einstärkenlinse (+2.1 ± 11.1 μm, +2.0 ± 11.1 μm, +1.6 ± 11.3 μm and +0.9 ± 11.2 μm jeweils). Außerdem erzeugt die ferndominante Multifokallinse im Vergleich zu der nahdominanten Multifokallinse und der Fern-Einstärkenlinse ein myoperes Refraktionsprofil. Änderungen der Glaskörpertiefe erfolgten in umgekehrter Richtung zu den Änderungen der Aderhautdicke. Schlussfolgerung: Multifokallinsen haben bei kurzer Tragedauer keinen signifikanten Einfluss auf die Aderhautdicke. Daraus lässt sich schließen, dass sie nicht der Hauptfaktor ist, der zu dem Kontrolleffekt bei Multifokallinsen führt. KW - Myopia KW - Defocus KW - Choroidal thickness KW - Multifocal contact lenses Y1 - 2018 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bsz:944-opus4-6800 ER -