Fifty milliliters of peripheral blood were collected in anticoagulated tubes and centrifuged at 900 g for 10 minutes to isolate platelet rich plasma (PRP). PRP was diluted to 30% (v/v) with sterile saline, frozen at -80°C for at least 60 minutes (thermal shock), and rapidly thawed at 4°C to induce platelet lysis. The resulting PL was aliquoted into sterile containers of 5 ml and 10 ml with a dropper tip, thus ensuring ease of administration to the patients' eyes. and stored at -20°C for approximately 45 days. On the day of use, vials were thawed at 4°C.

CB derived PL was produced based on the PL production process according to the already published protocol of the Hellenic Cord Blood Bank (HCBB) using cord blood units from full term pregnancies (38-40 weeks) that were unsuitable for transplantation according to the criteria of the World Accreditation Organization "FACT-NetCord" but donated for research with informed consent which was obtained prior to delivery and was in accordance with the National Bioethics Committee according to Helsinki declaration. PRP was isolated via double centrifugation, frozen at -80°C for at least 24 hours, and rapidly thawed at 37°C to release platelet derived growth factors. The lysate was filtered through a 0.22 μm non pyrogenic filter and aliquoted into 5-10 ml vials. Up to 10 ml of PL were obtained per cord blood unit. CB eye drops were stored at -20°C for up to 30 days without measurable loss of growth factor content.

For Autologous Serum preparation, 50 ml of peripheral blood were collected and centrifuged at 4000 g at +8°C for 15 minutes. A total of 3.5 ml of saline from preservative free eye drops was replaced with 3.5 ml of autologous serum. Infectious disease screening matched that of the PL group. Final products were stored for one week at +4°C and up to four weeks at -20°C.

For Autologous Serum preparation, 50 ml of peripheral blood were collected and centrifuged at 4000 g at +8°C for 15 minutes. A total of 3.5 ml of saline from preservative free eye drops was replaced with 3.5 ml of autologous serum. Infectious disease screening matched that of the PL group. Final products were stored for one week at +4°C and up to four weeks at -20°C.

For the assessment of the stability of the tear film, its breakup time was examined, that is, the time between the last blink and the appearance of the first dry spot after instillation of 2% fluorescein into the eye. A time of less than 5 seconds is considered indicative of ocular surface disease.

For the assessment of tear production, the Schirmer test was used (amount of wetting of a special filter paper), the examination was performed without the use of local anesthesia. If the length of wetting after 5 minutes is less than 10 mm, then it is considered pathological.

The Oxford Scale grades ocular surface staining from 0 to 5, where 0 indicates no staining and 5 indicates severe corneal damage. It measures the severity of corneal staining using dyes like fluorescein.

The OSDI is a 12-item questionnaire assessing ocular symptoms, visual functioning, and environmental triggers. Each is scored 0-4 and converted to a 0-100 total score. Scores classify as normal, mild, moderate, severe.