Vitamin A and fish oils for preventing the progression of retinitis pigmentosa.

BACKGROUND: Retinitis pigmentosa (RP) comprises a group of hereditary eye diseases characterized by progressive degeneration of retinal photoreceptors. It results in severe visual loss that may lead to blindness. Symptoms may become manifest during childhood or adulthood which include poor night vision (nyctalopia) and constriction of peripheral vision (visual field loss). Visual field loss is progressive and affects central vision later in the disease course. The worldwide prevalence of RP is approximately 1 in 4000, with 100,000 individuals affected in the USA. At this time, there is no proven therapy for RP. OBJECTIVES: The objective of this review was to synthesize the best available evidence regarding the effectiveness and safety of vitamin A and fish oils (docosahexaenoic acid (DHA)) in preventing the progression of RP. SEARCH METHODS: We searched the Cochrane Central Register of Controlled Trials (CENTRAL), which contains the Cochrane Eyes and Vision Trials Register (2020, Issue 2); Ovid MEDLINE; Embase.com; PubMed; Latin American and Caribbean Health Sciences Literature Database (LILACS); ClinicalTrials.gov; the World Health Organization (WHO) International Clinical Trials Registry Platform (ICTRP); and OpenGrey. We did not use any date or language restrictions in the electronic searches for trials. We last searched the electronic databases on 7 February 2020. SELECTION CRITERIA: We included randomized controlled trials that enrolled participants of any age diagnosed with any degree of severity or type of RP, and evaluated the effectiveness of vitamin A, fish oils (DHA), or both compared to placebo, vitamins (other than vitamin A), or no therapy, as a treatment for RP. We excluded cluster-randomized trials and cross-over trials. DATA COLLECTION AND ANALYSIS: We prespecified the following outcomes: mean change from baseline visual field, mean change from baseline electroretinogram (ERG) amplitudes, and anatomic changes as measured by optical coherence tomography (OCT), at one-year follow-up, and mean change in visual acuity, at five-year follow-up. Two review authors independently extracted data and evaluated risk of bias for all included trials. We also contacted study investigators for further information when necessary. MAIN RESULTS: In addition to three trials from the previous version of this review, we included a total of four trials with 944 participants aged 4 to 55 years. Two trials included only participants with X-linked RP and the other two included participants with RP of all forms of genetic predisposition. Two trials evaluated the effect of DHA alone; one trial evaluated vitamin A alone; and one trial evaluated DHA and vitamin A versus vitamin A alone. Two trials recruited participants from the USA, and the other two recruited from the USA and Canada. All trials were at low risk of bias for most domains. We did not perform meta-analysis due to clinical heterogeneity. Four trials assessed visual field sensitivity. Investigators found no evidence of a difference in mean values between the groups. However, one trial found that the annual rate of change of visual field sensitivity over four years favored the DHA group in foveal (-0.02 ± 0.55 (standard error (SE)) dB versus -0.47 ± 0.03 dB, P = 0.039), macular (-0.42 ± 0.05 dB versus -0.85 ± 0.03 dB, P = 0.031), peripheral (-0.39 ± 0.02 versus -0.86 ± 0.02 dB, P < 0.001), and total visual field sensitivity (-0.39 ± 0.02 versus -0.86 ± 0.02 dB, P < 0.001). The certainty of the evidence was very low. The four trials evaluated visual acuity (LogMAR scale) at a follow-up of four to six years. In one trial (208 participants), investigators found no evidence of a difference between the two groups, as both groups lost 0.7 letters of the Early Treatment Diabetic Retinopathy Study (ETDRS) visual acuity per year. In another trial (41 participants), DHA showed no evidence of effect on visual acuity (mean difference -0.01 logMAR units (95% confidence interval -0.14 to 0.12; one letter difference between the two groups; very low-certainty evidence). In the third trial (60 participants), annual change in mean number of letters correct was -0.8 (DHA) and 1.4 letters (placebo), with no evidence of between-group difference. In the fourth trial (572 participants), which evaluated (vitamin A + vitamin E trace) compared with (vitamin A trace + vitamin E trace), decline in ETDRS visual acuity was 1.1 versus 0.9 letters per year, respectively. All four trials reported electroretinography (ERG). Investigators of two trials found no evidence of a difference between the DHA and placebo group in yearly rates of change in 31 Hz cone ERG amplitude (mean ± SE) (-0.028 ± 0.001 log µV versus -0.022 ± 0.002 log µV; P = 0.30); rod ERG amplitude (mean ± SE) (-0.010 ± 0.001 log µV versus -0.023 ± 0.001 log µV; P = 0.27); and maximal ERG amplitude (mean ± SE) (-0.042 ± 0.001 log µV versus -0.036 ± 0.001 log µV; P = 0.65). In another trial, a slight difference (6.1% versus 7.1%) in decline of ERG per year favored vitamin A (P = 0.01). The certainty of the evidence was very low. One trial (51 participants) that assessed optical coherence tomography found no evidence of a difference in ellipsoid zone constriction (P = 0.87) over two years, with very low-certainty evidence. The other three trials did not report this outcome. Only one trial reported adverse events, which found that 27/60 participants experienced 42 treatment-related emergent adverse events (22 in DHA group, 20 in placebo group). The certainty of evidence was very low. The rest of the trials reported no adverse events, and no study reported any evidence of benefit of vitamin supplementation on the progression of visual acuity loss. AUTHORS' CONCLUSIONS: Based on the results of four studies, it is uncertain if there is a benefit of treatment with vitamin A or DHA, or both for people with RP. Future trials should also take into account the changes observed in ERG amplitudes and other outcome measures from trials included in this review.

Antimetabolites as an adjunct to dacryocystorhinostomy for nasolacrimal duct obstruction.

BACKGROUND: Nasolacrimal duct obstruction (NLDO) is a condition that results in the overflow of tears (epiphora) or infection of the nasolacrimal sac (dacryocystitis). The etiology of acquired NLDO is multifactorial and is not fully understood. Dacryocystorhinostomy (DCR) is the surgical correction of NLDO, which aims to establish a new drainage pathway between the lacrimal sac and the nose. The success of DCR is variable; the most common cause of failure is fibrosis and stenosis of the surgical ostium. Antimetabolites such as mitomycin-C (MMC) and 5-fluorouracil (5-FU) have been shown to be safe and effective in reducing fibrosis and improving clinical outcomes in other ophthalmic surgery settings (e.g. glaucoma and cornea surgery). Application of antimetabolites at the time of DCR has been studied, but the utility of these treatments remains uncertain. OBJECTIVES: Primary objective: To determine if adjuvant treatment with antimetabolites improves functional success in the setting of DCR compared to DCR alone. Secondary objectives: To determine if anatomic success of DCR is increased with the use of antimetabolites, and if the surgical ostium is larger in participants treated with antimetabolites. SEARCH METHODS: We searched the Cochrane Register for Controlled Trials (CENTRAL) (which contains the Cochrane Eye and Vision Trials Register) (2019, Issue 9), Ovid MEDLINE, Embase.com, PubMed, LILACS (Latin American and Caribbean Health Sciences Literature database), ClinicalTrials.gov, and the World Health Organization (WHO) International Clinical Trials Registry Platform (ICTRP). We did not use any date or language restrictions in the electronic searches. We last searched the electronic databases on 6 September 2019. SELECTION CRITERIA: We only included randomized controlled trials. Eligible studies were those that compared the administration of antimetabolites of any dose and concentration versus placebo or another active treatment in participants with NLDO undergoing primary DCR and reoperation. We only included studies that had enrolled adults 18 years or older. We also included studies that used silicone intubation as part of the DCR procedure. DATA COLLECTION AND ANALYSIS: We used standard methodological procedures expected by Cochrane. Two review authors independently screened the search results, assessed risk of bias, and extracted data from the included studies using an electronic data collection form. MAIN RESULTS: We included 31 studies in the review, of which 23 (1309 participants) provided data relating to our primary and secondary outcomes. Many of the 23 studies evaluated functional success, while others also assessed our secondary outcomes of anatomic success or ostium size, or both. Study characteristics Participant characteristics varied across studies, with the age of participants ranging from 30 to 70 years. Participants were predominantly women. These demographics correspond to those most frequently affected by nasolacrimal duct obstruction. Almost all of the studies utilized MMC as the antimetabolite, with only one using 5-FU. We assessed most trials as at unclear risk of bias for most domains. Conflicts of interest were not frequently reported, although the antimetabolites used are generic medications, and studies were not likely to be conducted for financial interest. Findings Twenty studies provided data on the primary outcome of functional success, of which 7 (356 participants) provided data at 6 months and 14 (909 participants) provided data beyond 6 months. At six months, the results showed no evidence of effect of antimetabolite on functional success (risk ratio (RR) 1.12, 95% confidence interval (CI) 0.98 to 1.29; low-certainty evidence). Beyond six months, the results favored the antimetabolite group (RR 1.15, 95% CI 1.07 to 1.25; moderate-certainty evidence). Fourteen studies reported data on the secondary outcome of anatomic success, of which 4 (306 participants) reported data at 6 months and 12 (831 participants) provided data beyond 6 months. Results at six months showed no evidence of effect of antimetabolite on anatomic success (RR 1.02, 95% CI 0.95 to 1.11; low-certainty evidence). Beyond six months, participants in the antimetabolite group were more likely to achieve anatomic success than those receiving DCR alone (RR 1.09, 95% CI 1.04 to 1.15; moderate-certainty evidence). At six months and beyond six months follow-up, two studies reported mean change in ostium size. We did not conduct meta-analysis for the various follow-up periods due to clinical, methodological, and statistical heterogeneity. However, point estimates from these studies at six months consistently favored participants in the antimetabolite group (low-certainty evidence). Beyond six months, while point estimates from one study favored participants in the antimetabolite group, estimates from another study showed no evidence of a difference between the two groups. The certainty of evidence at both time points was low. Adverse events Adverse events were rare. One study reported that one participant in the MMC group experienced delayed wound healing. Other studies reported no significant adverse events related to the application of antimetabolites. AUTHORS' CONCLUSIONS: There is moderate-certainty evidence that application of antimetabolites at the time of DCR increases functional and anatomic success of DCR when patients are followed for more than six months after surgery, but no evidence of a difference at six months, low-certainty of evidence. There is low-certainty evidence that combining antimetabolite with DCR increases the size of the lacrimal ostium at six months. However, beyond six months, the evidence remain uncertain. Adverse effects of the application of antimetabolites were minimal.