The aim of this study is to investigate whether natural progression rate can be slowed down with subtenon PRP or PRP application combined with rEMS in retinitis pigmentosa cases.

Retinitis pigmentosa (RP) is a progressive external retinal degeneration resulting from mutation in any of the 260 genes found in the retinal pigment epithelium (RPE). The progression rate and findings of the disease are heterogeneous according to genetic mutation and heredity type. The initial symptom of the disease is usually night blindness (nyctalopia) beginning in childhood or adolescent period. Narrowing in the visual field and legal blindness develops as the disease progresses. If low grade inflammation is added, the disease is complicated by cataracts, epiretinal membrane and macular edema. In the fundus examination, the appearance of midperiferal bone spicule pigmentation is usually sufficient to diagnosis. Developments in optical coherence tomography (OCT) technology enable detailed imaging of the sensorial retina and the ellipsoid zone. The ellipsoid zone (EZ) is an image of the inner and outer segments of photoreceptor cells. Loss of EZ is considered the gold standard in the diagnosis and follow-up of RP. Visual field monitoring and electroretinography (ERG) are indirect signs of EZ loss and correlated with EZ width. Mutations in RPE disrupt the synthesis of some vital peptide and growth factors for photoreceptors.

Platelet-rich plasma (PRP) is a good source of growth factors. Platelets have more than 30 growth factors and cytokines in α-granules such as neurotrophic growth factor (NGF), neural factor (NF), brain derived neurotrophic factor (BDNF), basic fibroblast growth factor (bFGF), insulin-like growth factor (IGF), transforming growth factor (TGF-β), vascular endothelial growth factor (VEGF), platelet derived growth factor (PDGF) etc. These peptides regulate the energy cycle at the cellular level, local capillary blood flow, neurogenesis and cellular metabolism. Anti-inflammatory effects of PRP are also associated with soluble cytokines.

Repetitive electromagnetic stimulation (rEMS), increases binding affinity and the synthesis of growth factor receptors on neural tissues. It provides electromagnetic iontophoresis by changing the electrical charges of tyrosine kinase receptors (Trk). rEMS forms hyperpolarization-depolarization waves in neurons, thereby increasing neurotransmission and capillary blood flow. Trk receptors are commonly found around limbus, extraocular muscle insertions and the optic nerve. Molecules smaller than 75 kD can pass from the sclera passively to the suprachoroidal space. Electrical or electromagnetic iontophoresis is required for molecules larger than 75kD such as BDNF and IGF to pass through the sclera.

The aim of this study is to investigate whether natural progression rate can be slowed down with subtenon PRP or PRP application combined with rEMS in retinitis pigmentosa cases.

Inclusion Criteria:

• RP patients in any phenotype with vision over 50 letters

Exclusion Criteria:

• Media opacity and nystagmus presence to prevent EZW imaging in OCT