Eyedrops made from autologous serum as a treatment for dry eye
Dry eye is a common disorder of the tear film, which is a layer of tears covering the surface of the eye. Dry eye affects many adults older than 40 years of age. One common treatment for dry eye is artificial tears, which provide lubrication to the surface of the eye. However, artificial tears lack the biologically active components found in natural tears that are critical to the maintenance of the tear film. Eye drops made by separating the liquid and cellular components of the patient’s blood, known as autologous serum eye drops, have been shown to possess many of the same biological nutrients found in natural tears. Because of this, autologous serum eye drops are believed to be a better tear substitute and have become a common treatment for dry eye.
We conducted a wide range of searches for relevant trials in April 2013. We identified four randomized controlled trials with a total of 72 participants with dry eye from Chile, Australia and Japan. The trials compared autologous serum eye drops to traditional artificial tears for the treatment of dry eye. The results from the four trials could not be combined in analysis due to the variation in participant populations, follow‐up intervals, and incomplete reporting of treatment outcomes. None of the included trials reported outcomes for the primary outcome of this review, the change in participant‐reported symptoms after one month of treatment. Some improvements in participant‐reported outcomes and tear film stability were seen in two trials after two weeks, but not in the other two trials or at longer follow‐up periods. Autologous serum eye drops did not provide a benefit based on other clinical assessments of the surface of the eye compared to traditional artificial tears. Outcomes for quality or life and costs were not reported in any of the trials. One study reported that no serious harms were related to using autologous serum eye drops while the other studies did not discuss whether any adverse events occurred. Overall the results from these studies do not provide consistent information as to whether autologous serum eye drops are safe and effective for the treatment of dry eye. Future trials are needed using appropriate study designs to address participant‐centered outcomes, to determine the effects of autologous serum eye drops in the treatment of dry eye.
Background: Theoretically, autologous serum eye drops (AS) have a potential advantage over traditional therapies based on the assumption that AS serve not only as a lacrimal substitute to provide lubrication, but also contain other biochemical components mimicking natural tears more closely. The application of AS in dry eye treatment has gained popularity as a second‐line therapy in the treatment of dry eye. Published studies on the subject indicate that autologous serum could be an effective treatment for dry eye.
Objectives: To evaluate the efficacy and safety of AS compared to artificial tears for treating dry eye.
Search methods: We searched CENTRAL (which contains the Cochrane Eyes and Vision Group Trials Register) (The Cochrane Library 2013, Issue 3), Ovid MEDLINE, Ovid MEDLINE In‐Process and Other Non‐Indexed Citations, Ovid MEDLINE Daily, Ovid OLDMEDLINE, (January 1950 to April 2013), EMBASE (January 1980 to April 2013), Latin American and Caribbean Literature on Health Sciences (LILACS) (January 1982 to April 2013), the metaRegister of Controlled Trials (mRCT) (www.controlled‐trials.com), ClinicalTrials.gov (www.clinicaltrials.gov) and the WHO International Clinical Trials Registry Platform (ICTRP) (www.who.int/ictrp/search/en). We also searched the Science Citation Index Expanded database (September 2013) and reference lists of included studies. We did not use any date or language restrictions in the electronic searches for trials. We last searched the electronic databases on 15 April 2013.
Selection criteria: We included randomized controlled trials (RCTs) in which AS was compared to artificial tears in the treatment of dry eye in adults.
Data collection and analysis: Two review authors independently screened all titles and abstracts and assessed full‐text articles of potentially eligible trials. Two review authors extracted data and assessed the methodological quality and characteristics of the included trials. We contacted investigators for missing data. For both primary and secondary outcomes, we reported mean differences with corresponding 95% confidence intervals (CIs) for continuous outcomes.
Main results: We identified four eligible RCTs in which AS was compared with artificial tear treatment or saline in individuals (n = 72 participants) with dry eye of various etiologies (Sjögren's syndrome‐related dry eye, non‐Sjögren's syndrome dry eye and postoperative dry eye induced by laser‐assisted in situ keratomileusis (LASIK)). The quality of the evidence provided by these trials was variable. A majority of the risk of bias domains were judged to have an unclear risk of bias in two trials owing to insufficient reporting of trial characteristics. One trial was considered to have a low risk of bias for most domains while another was considered to have a high risk of bias for most domains. Incomplete outcome reporting and heterogeneity in the participant populations and follow‐up periods prevented the inclusion of these trials in a summary meta‐analysis. For the primary outcome, improvement in participant‐reported symptoms at one month, one trial (12 participants) showed no difference in participant‐reported symptoms between 20% AS and artificial tears. Based on the results of two trials in 32 participants, 20% AS may provide some improvement in participant‐reported symptoms compared to traditional artificial tears after two weeks of treatment. One trial also showed positive results with a mean difference in tear break‐up time (TBUT) of 2.00 seconds (95% CI 0.99 to 3.01 seconds) between 20% AS and artificial tears after two weeks, which were not similar to findings from the other trials. Based on all other objective clinical assessments included in this review, AS was not associated with improvements in aqueous tear production measured by Schirmer’s test (two trials, 33 participants), ocular surface condition with fluorescein (four trials, 72 participants) or Rose Bengal staining (three trials, 60 participants), and epithelial metaplasia by impression cytology compared to artificial tears (one trial, 12 participants). Data on adverse effects were not reported by three of the included studies. In one study, there were no serious adverse events reported with the collection of and treatment with AS.
Authors' conclusions: Overall there was inconsistency in the possible benefits of AS in improving participant‐reported symptoms and TBUT and lack of effect based on other objective clinical measures. Well‐planned, large, high‐quality RCTs are warranted, in different severities of dry eye and using standardized questionnaires to measure participant‐reported outcomes and objective clinical tests as well as objective biomarkers to assess the benefit of AS therapy for dry eye.