Laser-assisted cataract surgery versus standard ultrasound phacoemulsification cataract surgery

BACKGROUND

Cataract is the leading cause of blindness in the world and, as such, cataract surgery is one of the most commonly performed operations globally. Surgical techniques have changed dramatically over the past half century with associated improvements in outcomes and safety. Femtosecond lasers can be used to perform the key steps in cataract surgery, such as corneal incisions, lens capsulotomy and fragmentation. The potential advantage of femtosecond laser-assisted cataract surgery (FLACS) is greater precision and reproducibility of these steps compared to manual techniques. The disadvantages are the costs associated with FLACS technology.

OBJECTIVES

To compare the effectiveness and safety of FLACS with standard ultrasound phacoemulsification cataract surgery (PCS) by gathering evidence from randomised controlled trials (RCTs).

SEARCH METHODS

We searched the Cochrane Central Register of Controlled Trials (CENTRAL; which contains the Cochrane Eyes and Vision Trials Register; 2022, Issue 5); Ovid MEDLINE; Ovid Embase; LILACS; the ISRCTN registry; ClinicalTrials.gov; the WHO ICTRP and the US Food and Drug Administration (FDA) website. We did not use any date or language restrictions in the electronic searches for trials. We last searched the electronic databases on 10 May 2022.

SELECTION CRITERIA

We included RCTs where FLACS was compared to PCS.

DATA COLLECTION AND ANALYSIS

Three review authors independently screened the search results, assessed risk of bias and extracted data using the standard methodological procedures expected by Cochrane. The primary outcome for this review was intraoperative complications in the operated eye, namely anterior capsule, and posterior capsule tears. The secondary outcomes included corrected distance visual acuity (CDVA), quality of vision (as measured by any validated patient-reported outcome measure (PROM)), postoperative cystoid macular oedema complications, endothelial cell loss and cost-effectiveness. We assessed the certainty of the evidence using GRADE.

MAIN RESULTS

We included 42 RCTs conducted in Europe, North America, South America and Asia, which enrolled a total of 7298 eyes of 5831 adult participants. Overall, the studies were at unclear or high risk of bias. In 16 studies the authors reported financial links with the manufacturer of the laser platform evaluated in their studies. Thirteen of the studies were within-person (paired-eye) studies with one eye allocated to one procedure and the other eye allocated to the other procedure. These studies were reported ignoring the paired nature of the data. There was low-certainty evidence of little or no difference in the odds of developing anterior capsular tears when comparing FLACS and PCS (Peto odds ratio (OR) 0.83, 95% confidence interval (CI) 0.40 to 1.72; 5835 eyes, 27 studies) There was one fewer anterior capsule tear per 1000 operations in the FLACS group compared with the PCS group (95% CI 4 fewer to 3 more).  There was low-certainty evidence of lower odds of developing posterior capsular tears with FLACS compared to PCS (Peto OR 0.50, 95% CI 0.25 to 1.00; 5767 eyes, 26 studies). There were four fewer posterior capsule tears per 1000 operations in the FLACS group compared with the PCS group (95% CI 6 fewer to same).  There was moderate-certainty evidence of a very small advantage for the FLACS arm with regard to CDVA at six months or more follow-up, (mean difference (MD) -0.01 logMAR, 95% CI -0.02 to 0.00; 1323 eyes, 7 studies). This difference is equivalent to 1 logMAR letter between groups and is not thought to be clinically important. From the three studies (1205 participants) reporting a variety of PROMs (Cat-PROMS, EQ-5D, EQ-SD-3L, Catquest9-SF and patient survey) up to three months following surgery, there was moderate-certainty evidence of little or no difference in the various parameters between the two treatment arms. There was low-certainty evidence of little or no difference in the odds of developing cystoid macular oedema when comparing FLACS and PCS (Peto OR 0.84, 95% CI 0.56 to 1.28; 4441 eyes, 18 studies). There were three fewer cystoid macular oedema cases per 1000 operations in the FLACS group compared with the PCS group (95% CI 10 fewer to 6 more).  In one study the incremental cost-effectiveness ratio (ICER) (cost difference divided by quality-adjusted life year (QALY) difference) was GBP £167,620 when comparing FLACS to PCS. In another study, the ICER was EUR €10,703 saved per additional patient who had treatment success with PCS compared to FLACS. Duration ranged from three minutes in favour of FLACS to eight minutes in favour of PCS (I2 = 100%, 11 studies) (low-certainty evidence).  There was low-certainty evidence of little or no important difference in endothelial cell loss when comparing FLACS with PCS (MD 12 cells per mm2 in favour of FLACS, 95% CI -40 to 64; 1512 eyes, 10 studies).  AUTHORS' CONCLUSIONS: This review of 42 studies provides evidence that there is probably little or no difference between FLACS and PCS in terms of intraoperative and postoperative complications, postoperative visual acuity and quality of life. Evidence from two studies suggests that FLACS may be the less cost-effective option. Many of the included studies only investigated very specific outcome measures such as effective phacoemulsification time, endothelial cell count change or aqueous flare, rather than those directly related to patient outcomes. Standardised reporting of complications and visual and refractive outcomes for cataract surgery would facilitate future synthesis, and guidance on this has been recently published.

Fenofibrate for diabetic retinopathy

BACKGROUND

Diabetic retinopathy (DR) remains a major cause of sight loss worldwide, despite new therapies and improvements in the metabolic control of people living with diabetes. Therefore, DR creates a physical and psychological burden for people, and an economic burden for society. Preventing the development and progression of DR, or avoiding the occurrence of its sight-threatening complications is essential, and must be pursued to save sight. Fenofibrate may be a useful strategy to achieve this goal, by reversing diabetes' effects and reducing inflammation in the retina, as well as improving dyslipidaemia and hypertriglyceridaemia.  OBJECTIVES: To investigate the benefits and harms of fenofibrate for preventing the development and progression of diabetic retinopathy in people with type 1 (T1D) or type 2 diabetes (T2D), compared with placebo or observation.

SEARCH METHODS

We searched CENTRAL, MEDLINE, Embase, and three trials registers (February 2022).

SELECTION CRITERIA

We included randomised controlled trials (RCTs) that included people with T1D or T2D, when these compared fenofibrate with placebo or with observation, and assessed the effect of fenofibrate on the development or progression of DR (or both).

DATA COLLECTION AND ANALYSIS

We used standard Cochrane methods for data extraction and analysis. Our primary outcome was progression of DR, a composite outcome of 1) incidence of overt retinopathy for participants who did not have DR at baseline, or 2) advancing two or more steps on the Early Treatment Diabetic Retinopathy Study (ETDRS) severity scale for participants who had any DR at baseline (or both), based on the evaluation of stereoscopic or non-stereoscopic fundus photographs, during the follow-up period. Overt retinopathy was defined as the presence of any DR observed on stereoscopic or non-stereoscopic colour fundus photographs. Secondary outcomes included the incidence of overt retinopathy, reduction in visual acuity of participants with a reduction in visual acuity of 10 ETDRS letters or more, proliferative diabetic retinopathy, and diabetic macular oedema; mean vision-related quality of life, and serious adverse events of fenofibrate. We used GRADE to assess the certainty of evidence.

MAIN RESULTS

We included two studies and their eye sub-studies (15,313 participants) in people with T2D. The studies were conducted in the US, Canada, Australia, Finland, and New Zealand; follow-up period was four to five years. One was funded by the government, the other by industry. Compared to placebo or observation, fenofibrate likely results in little to no difference in progression of DR (risk ratio (RR) 0.86; 95% confidence interval (CI) 0.60 to 1.25; 1 study, 1012 participants; moderate-certainty evidence) in a population with and without overt retinopathy at baseline. Those without overt retinopathy at baseline showed little or no progression (RR 1.00, 95% CI 0.68 to 1.47; 1 study, 804 participants); those with overt retinopathy at baseline found that their DR progressed slowly (RR 0.21, 95% CI 0.06 to 0.71; 1 study, 208 people; test for interaction P = 0.02). Compared to placebo or observation, fenofibrate likely resulted in little to no difference in either the incidence of overt retinopathy (RR 0.91; 95% CI 0.76 to 1.09; 2 studies, 1631 participants; moderate-certainty evidence); or the incidence of diabetic macular oedema (RR 0.39; 95% CI 0.12 to 1.24; 1 study, 1012 participants; moderate-certainty evidence). The use of fenofibrate increased severe adverse effects (RR 1.55; 95% CI 1.05 to 2.27; 2 studies, 15,313 participants; high-certainty evidence). The studies did not report on incidence of a reduction in visual acuity of 10 ETDRS letters or more, incidence of proliferative diabetic retinopathy, or mean vision-related quality of life.

AUTHORS' CONCLUSIONS

Current, moderate-certainty evidence suggests that in a mixed group of people with and without overt retinopathy, who live with T2D, fenofibrate likely results in little to no difference in progression of diabetic retinopathy. However, in people with overt retinopathy who live with T2D, fenofibrate likely reduces the progression. Serious adverse events were rare, but the risk of their occurrence was increased by the use of fenofibrate. There is no evidence on the effect of fenofibrate in people with T1D. More studies, with larger sample sizes, and participants with T1D are needed. They should measure outcomes that are important to people with diabetes, e.g. change in vision, reduction in visual acuity of 10 ETDRS letters or more, developing proliferative diabetic retinopathy; and evaluating the requirement of other treatments, e.g. injections of anti-vascular endothelial growth factor therapies, steroids.

Non-steroidal anti-inflammatory drugs versus corticosteroids for controlling inflammation after uncomplicated cataract surgery

BACKGROUND

Cataract is a leading cause of blindness worldwide. Cataract surgery is commonly performed but can result in postoperative inflammation of the eye. Inadequately controlled inflammation increases the risk of complications. Non-steroidal anti-inflammatory drugs (NSAIDs) and corticosteroids are used to prevent and reduce inflammation following cataract surgery, but these two drug classes work by different mechanisms. Corticosteroids are effective, but NSAIDs may provide an additional benefit to reduce inflammation when given in combination with corticosteroids. A comparison of NSAIDs to corticosteroids alone or combination therapy with these two anti-inflammatory agents will help to determine the role of NSAIDs in controlling inflammation after routine cataract surgery.

OBJECTIVES

To evaluate the comparative effectiveness of topical NSAIDs (alone or in combination with topical corticosteroids) versus topical corticosteroids alone in controlling intraocular inflammation after uncomplicated phacoemulsification. To assess postoperative best-corrected visual acuity (BCVA), patient-reported discomfort, symptoms, or complications (such as elevation of IOP), and cost-effectiveness with the use of postoperative NSAIDs or corticosteroids.

SEARCH METHODS

To identify studies relevant to this review, we searched the Cochrane Central Register of Controlled Trials (CENTRAL), which contains the Cochrane Eyes and Vision Trials Register (2016, Issue 12), MEDLINE Ovid (1946 to December 2016), Embase Ovid (1947 to 16 December 2016), PubMed (1948 to December 2016), LILACS (Latin American and Caribbean Health Sciences Literature Database) (1982 to 16 December 2016), the metaRegister of Controlled Trials (mRCT) (www.controlled-trials.com; last searched 17 June 2013), ClinicalTrials.gov (www.clinicaltrials.gov; searched December 2016), and the WHO International Clinical Trials Registry Platform (ICTRP) (www.who.int/ictrp/search/en; searched December 2016).

SELECTION CRITERIA

We included randomized controlled trials (RCTs) in which participants were undergoing phacoemulsification for uncomplicated cataract extraction. We included both trials in which topical NSAIDs were compared with topical corticosteroids and trials in which combination therapy (topical NSAIDs and corticosteroids) was compared with topical corticosteroids alone. The primary outcomes for this review were inflammation and best-corrected visual acuity (BCVA).

DATA COLLECTION AND ANALYSIS

Two review authors independently screened the full-text articles, extracted data from included trials, and assessed included trials for risk of bias according to Cochrane standards. The two review authors resolved any disagreements by discussion. We graded the certainty of the evidence using GRADE.

MAIN RESULTS

This review included 48 RCTs conducted in 17 different countries and two ongoing studies. Ten included studies had a trial registry record. Fifteen studies compared an NSAID with a corticosteroid alone, and 19 studies compared a combination of an NSAID plus a corticosteroid with a corticosteroid alone. Fourteen other studies had more than two study arms. Overall, we judged the studies to be at unclear risk of bias. NSAIDs alone versus corticosteroids aloneNone of the included studies reported postoperative intraocular inflammation in terms of cells and flare as a dichotomous variable. Inflammation was reported as a continuous variable in seven studies. There was moderate-certainty evidence of no difference in mean cell value in the participants receiving an NSAID compared with the participants receiving a corticosteroid (mean difference (MD) -0.60, 95% confidence interval (CI) -2.19 to 0.99), and there was low-certainty evidence that the mean flare value was lower in the group receiving NSAIDs (MD -13.74, 95% CI -21.45 to -6.04). Only one study reported on corneal edema at one week postoperatively and there was uncertainty as to whether the risk of edema was higher or lower in the group that received NSAIDs (risk ratio (RR) 0.77, 95% CI 0.26 to 2.29). No included studies reported BCVA as a dichotomous outcome and no study reported time to cessation of treatment. None of the included studies reported the proportion of eyes with cystoid macular edema (CME) at one week postoperatively. Based on four RCTs that reported CME at one month, we found low-certainty evidence that participants treated with an NSAID alone had a lower risk of developing CME compared with those treated with a corticosteroid alone (RR 0.26, 95% CI 0.17 to 0.41). No studies reported on other adverse events or economic outcomes. NSAIDs plus corticosteroids versus corticosteroids aloneNo study described intraocular inflammation in terms of cells and flare as a dichotomous variable and there was not enough continuous data for anterior chamber cell and flare to perform a meta-analysis. One study reported presence of corneal edema at various times. Postoperative treatment with neither a combination treatment with a NSAID plus corticosteroid or with corticosteroid alone was favored (RR 1.07, 95% CI 0.98 to 1.16). We judged this study to have high risk of reporting bias, and the certainty of the evidence was downgraded to moderate. No included study reported the proportion of participants with BCVA better than 20/40 at one week postoperatively or reported time to cessation of treatment. Only one included study reported on the presence of CME at one week after surgery and one study reported on CME at two weeks after surgery. After combining findings from these two studies, we estimated with low-certainty evidence that there was a lower risk of CME in the group that received NSAIDs plus corticosteroids (RR 0.17, 95% CI 0.03 to 0.97). Seven RCTs reported the proportion of participants with CME at one month postoperatively; however there was low-certainty evidence of a lower risk of CME in participants receiving an NSAID plus a corticosteroid compared with those receiving a corticosteroid alone (RR 0.50, 95% CI 0.23 to 1.06). The few adverse events reported were due to phacoemulsification rather than the eye drops.

AUTHORS' CONCLUSIONS

We found insufficient evidence from this review to inform practice for treatment of postoperative inflammation after uncomplicated phacoemulsification. Based on the RCTs included in this review, we could not conclude the equivalence or superiority of NSAIDs with or without corticosteroids versus corticosteroids alone. There may be some risk reduction of CME in the NSAID-alone group and the combination of NSAID plus corticosteroid group. Future RCTs on these interventions should standardize the type of medication used, dosing, and treatment regimen; data should be collected and presented using the Standardization of Uveitis Nomenclature (SUN) outcome measures so that dichotomous outcomes can be analyzed.

Laser-assisted cataract surgery versus standard ultrasound phacoemulsification cataract surgery

BACKGROUND

Cataract is the leading cause of blindness in the world, and cataract surgery is one of the most commonly performed operations in the Western world. Preferred surgical techniques have changed dramatically over the past half century with associated improvements in outcomes and safety. Femtosecond laser platforms that can accurately and reproducibly perform key steps in cataract surgery, including corneal incisions, capsulotomy and lens fragmentation, are now available. The potential advantages of laser-assisted surgery are broad, and include greater safety and better visual outcomes through greater precision and reproducibility.

OBJECTIVES

To compare the effectiveness of laser-assisted cataract surgery with standard ultrasound phacoemulsification cataract surgery by gathering evidence on safety from randomised controlled trials (RCTs).

SEARCH METHODS

We searched CENTRAL (which contains the Cochrane Eyes and Vision Trials Register) (2016, Issue 4), Ovid MEDLINE, Ovid MEDLINE In-Process and Other Non-Indexed Citations, Ovid MEDLINE Daily, Ovid OLDMEDLINE (January 1946 to May 2016), EMBASE (January 1980 to May 2016), Latin American and Caribbean Health Sciences Literature Database (LILACS) (January 1982 to May 2016), the ISRCTN registry (www.isrctn.com/editAdvancedSearch), ClinicalTrials.gov (www.clinicaltrials.gov), the World Health Organization (WHO) International Clinical Trials Registry Platform (ICTRP) (www.who.int/ictrp/search/en) and the U.S. Food and Drugs Administration (FDA) website (www.fda.gov). We did not use any date or language restrictions in the electronic searches for trials. We last searched the electronic databases on 10 May 2016.

SELECTION CRITERIA

We included randomised controlled trials where laser-assisted cataract surgery was compared to standard ultrasound phacoemulsification cataract surgery. We graded the certainty of the evidence using GRADE.

DATA COLLECTION AND ANALYSIS

Two review authors independently screened the search results, assessed risk of bias and extracted data using the standard methodological procedures expected by Cochrane. The primary outcome for this review was intraoperative complications in the operated eye, namely anterior capsule and posterior capsule tears. The secondary outcomes were visual acuity (corrected distance visual acuity (CDVA) and uncorrected distance visual acuity (UDVA)), refractive outcomes, quality of vision (as measured by any validated visual function score), postoperative complications and cost-effectiveness.

MAIN RESULTS

We included 16 RCTs conducted in Germary, Hungary, Italy, India, China and Brazil that enrolled a total of 1638 eyes of 1245 adult participants. Overall, the studies were at unclear or high risk of bias. In 11 of the studies the authors reported financial links with the manufacturer of the laser platform evaluated in their studies. Five of the studies were within-person (paired-eye) studies with one eye allocated to one procedure and the other eye allocated to the other procedure. These studies were reported ignoring the paired nature of the data.The number of anterior capsule and posterior capsule tears reported in the included studies for both laser cataract surgery and manual phacoemulsification cataract surgery were low. There were four anterior capsule tears and one posterior capsule tear in 1076 eyes reported in 10 studies (2 anterior capsule tears in laser arms, 2 anterior capsule tears and 1 posterior capsule tear in standard phacoemulsification arms). We are very uncertain as to the effect of laser-assisted surgery compared to standard phacoemulsification surgery with respect to these two outcomes. For postoperative cystoid macular oedema and elevated postoperative intraocular pressures, again the evidence was inconclusive (odds ratio (OR) 0.58, 95% confidence interval (CI) 0.20 to 1.68; 957 eyes, 9 studies, low certainty evidence; and OR 0.57, 95% CI 0.11 to 2.86; 903 eyes, 8 studies, low certainty evidence).We found little evidence of any important difference in postoperative visual acuity between laser-assisted and standard phacoemulsification arms. There was a small advantage for laser-assisted cataract surgery at six months in CDVA. However, the mean difference (MD) was -0.03 logMAR (95% CI -0.05 to -0.00; 224 eyes, 3 studies, low certainty evidence) which is equivalent to 1.5 logMAR letters and is therefore, clinically insignificant. No studies reported patient-reported outcome measures such as visual function.There were no data reported on costs or resource use but three studies reported the time taken to do the surgery. There was little evidence of any major difference between the two procedures in this respect (MD 0.1 minutes, 95% CI -0.02 to 0.21; 274 eyes, low certainty evidence).

AUTHORS' CONCLUSIONS

The evidence from the 16 randomised controlled trials RCTs included in this review could not determine the equivalence or superiority of laser-assisted cataract surgery compared to standard manual phacoemulsification for our chosen outcomes due to the low to very low certainty of the evidence available from these studies. As complications occur rarely, large, adequately powered, well designed, independent RCTs comparing the safety and efficacy of laser-assisted cataract surgery with standard phacoemulsification cataract surgery are needed. Standardised reporting of complications and visual and refractive outcomes for cataract surgery would facilitate future synthesis. Data on patient-reported outcomes and cost-effectiveness are needed. Paired-eye studies should be analysed and reported appropriately.

Macular grid laser photocoagulation for branch retinal vein occlusion

BACKGROUND

Branch retinal vein occlusion (BRVO) is the second most common cause of retinal vascular abnormality after diabetic retinopathy. Persistent macular oedema develops in 60% of eyes with a BRVO. Untreated, only 14% of eyes with chronic macular oedema will have a visual acuity (VA) of 20/40 or better. Macular grid laser photocoagulation is used for chronic non-ischaemic macular oedema following BRVO and has been the mainstay of treatment for over 20 years. New treatments are available and a systematic review is necessary to ensure that the most up-to-date evidence is considered objectively.

OBJECTIVES

To examine the effects of macular grid laser photocoagulation in the treatment of macular oedema following BRVO.

SEARCH METHODS

We searched CENTRAL, Ovid MEDLINE, EMBASE, Web of Science Conference Proceedings Citation Index, the metaRegister of Controlled Trials (mRCT), ClinicalTrials.gov and the WHO International Clinical Trials Registry Platform. We did not use any date or language restrictions in the electronic searches for trials. We last searched the electronic databases on 21 August 2014.

SELECTION CRITERIA

We included randomised controlled trials (RCTs) comparing macular grid laser photocoagulation treatment to another treatment, sham treatment or no treatment.

DATA COLLECTION AND ANALYSIS

We used standard methodological procedures expected by Cochrane.

MAIN RESULTS

We included five studies conducted in Europe and North America. Four separate trials compared grid laser to no treatment, sham treatment, intravitreal bevacizumab and intravitreal triamcinolone. One further trial compared subthreshold to threshold laser. Two of these trials were judged to be at high risk of bias in one or more domains.In one trial of grid laser versus observation, people receiving grid laser were more likely to gain visual acuity (VA) (10 or more ETDRS letters) at 36 months (RR 1.75, 95% confidence interval (CI) 1.08 to 2.84, 78 participants, moderate-quality evidence). The effect of grid laser on loss of VA (10 or more letters) was uncertain as the results were imprecise (RR 0.68, 95% CI 0.23 to 2.04, 78 participants, moderate-quality evidence). On average, people receiving grid laser had better improvement in VA (mean difference (MD) 0.11 logMAR, 95% CI 0.05 to 0.17, high-quality evidence). In a trial of early and delayed grid laser treatment versus sham laser (n = 108, data available for 99 participants), no participant gained or lost VA (15 or more ETDRS letters). At 12 months, there was no evidence for a difference in change in VA (from baseline) between early grid laser and sham laser (MD -0.03 logMAR, 95% confidence interval (CI) -0.07 to 0.01, 68 participants, low-quality evidence) or between delayed grid laser and sham laser (MD 0.00, 95% CI -0.04 to 0.04, 66 participants, low-quality evidence).The relative effects of subthreshold and threshold laser were uncertain. In one trial, the RR for gain of VA (15 or more letters) at 12 months was 1.68 (95% CI 0.57 to 4.95, 36 participants, moderate-quality evidence); the RR for loss of VA (15 or more letters) was 0.56 (95% CI 0.06 to 5.63, moderate-quality evidence); and at 24 months the change in VA from baseline was MD 0.07 (95% CI -0.10 to 0.24, moderate-quality evidence).The relative effects of macular grid laser and intravitreal bevacizumab were uncertain. In one trial, the RR for gain of 15 or more letters at 12 months was 0.67 (95% CI 0.39 to 1.14, 30 participants, low-quality evidence). Loss of 15 or more letters was not reported. Change in VA at 12 months was MD 0.11 logMAR (95% CI -0.36 to 0.14, low-quality evidence).The relative effects of grid laser and 1mg triamcinolone were uncertain at 12 months. RR for gain of VA (15 or more letters) was 1.13 (95% CI 0.75 to 1.71, 1 RCT, 242 participants, moderate-quality evidence); RR for loss of VA (15 or more letters) was 1.20 (95% CI 0.63 to 2.27, moderate-quality evidence); MD for change in VA was -0.03 letters (95% CI -0.12 to 0.06, moderate-quality evidence). Similar results were seen for the comparison with 4mg triamcinolone. Beyond 12 months, the visual outcomes were in favour of grid laser at 24 months and 36 months with people in the macular grid group gaining more VA.Four studies reported on adverse effects. Laser photocoagulation appeared to be well tolerated in the studies. One participant (out of 71) suffered a perforation of Bruch's membrane, but this did not affect visual acuity.

AUTHORS' CONCLUSIONS

Moderate-quality evidence from one RCT supports the use of grid laser photocoagulation to treat macular oedema following BRVO. There was insufficient evidence to support the use of early grid laser or subthreshold laser. There was insufficient evidence to show a benefit of intravitreal triamcinolone or anti-vascular endothelial growth factor (VEGF) over macular grid laser photocoagulation in BRVO. With recent interest in the use of intravitreal anti-VEGF or steroid therapy, assessment of treatment efficacy (change in visual acuity and foveal or central macular thickness using optical coherence tomography (OCT)) and the number of treatments needed for maintenance and long-term safety will be important for future studies.

Optical coherence tomography (OCT) for detection of macular oedema in patients with diabetic retinopathy

BACKGROUND

Diabetic macular oedema (DMO) is a thickening of the central retina, or the macula, and is associated with long-term visual loss in people with diabetic retinopathy (DR). Clinically significant macular oedema (CSMO) is the most severe form of DMO. Almost 30 years ago, the Early Treatment Diabetic Retinopathy Study (ETDRS) found that CSMO, diagnosed by means of stereoscopic fundus photography, leads to moderate visual loss in one of four people within three years. It also showed that grid or focal laser photocoagulation to the macula halves this risk. Recently, intravitreal injection of antiangiogenic drugs has also been used to try to improve vision in people with macular oedema due to DR.Optical coherence tomography (OCT) is based on optical reflectivity and is able to image retinal thickness and structure producing cross-sectional and three-dimensional images of the central retina. It is widely used because it provides objective and quantitative assessment of macular oedema, unlike the subjectivity of fundus biomicroscopic assessment which is routinely used by ophthalmologists instead of photography. Optical coherence tomography is also used for quantitative follow-up of the effects of treatment of CSMO.

OBJECTIVES

To determine the diagnostic accuracy of OCT for detecting DMO and CSMO, defined according to ETDRS in 1985, in patients referred to ophthalmologists after DR is detected. In the update of this review we also aimed to assess whether OCT might be considered the new reference standard for detecting DMO.

SEARCH METHODS

We searched the Cochrane Database of Systematic Reviews (CDSR), the Database of Abstracts of Reviews of Effects (DARE), the Health Technology Assessment Database (HTA) and the NHS Economic Evaluation Database (NHSEED) (The Cochrane Library 2013, Issue 5), Ovid MEDLINE, Ovid MEDLINE In-Process and Other Non-Indexed Citations, Ovid MEDLINE Daily, Ovid OLDMEDLINE (January 1946 to June 2013), EMBASE (January 1950 to June 2013), Web of Science Conference Proceedings Citation Index - Science (CPCI-S) (January 1990 to June 2013), BIOSIS Previews (January 1969 to June 2013), MEDION and the Aggressive Research Intelligence Facility database (ARIF). We did not use any date or language restrictions in the electronic searches for trials. We last searched the electronic databases on 25 June 2013. We checked bibliographies of relevant studies for additional references.

SELECTION CRITERIA

We selected studies that assessed the diagnostic accuracy of any OCT model for detecting DMO or CSMO in patients with DR who were referred to eye clinics. Diabetic macular oedema and CSMO were diagnosed by means of fundus biomicroscopy by ophthalmologists or stereophotography by ophthalmologists or other trained personnel.

DATA COLLECTION AND ANALYSIS

Three authors independently extracted data on study characteristics and measures of accuracy. We assessed data using random-effects hierarchical sROC meta-analysis models.

MAIN RESULTS

We included 10 studies (830 participants, 1387 eyes), published between 1998 and 2012. Prevalence of CSMO was 19% to 65% (median 50%) in nine studies with CSMO as the target condition. Study quality was often unclear or at high risk of bias for QUADAS 2 items, specifically regarding study population selection and the exclusion of participants with poor quality images. Applicablity was unclear in all studies since professionals referring patients and results of prior testing were not reported. There was a specific 'unit of analysis' issue because both eyes of the majority of participants were included in the analyses as if they were independent.In nine studies providing data on CSMO (759 participants, 1303 eyes), pooled sensitivity was 0.78 (95% confidence interval (CI) 0.72 to 0.83) and specificity was 0.86 (95% CI 0.76 to 0.93). The median central retinal thickness cut-off we selected for data extraction was 250 µm (range 230 µm to 300 µm). Central CSMO was the target condition in all but two studies and thus our results cannot be applied to non-central CSMO.Data from three studies reporting accuracy for detection of DMO (180 participants, 343 eyes) were not pooled. Sensitivities and specificities were about 0.80 in two studies and were both 1.00 in the third study.Since this review was conceived, the role of OCT has changed and has become a key ingredient of decision-making at all levels of ophthalmic care in this field. Moreover, disagreements between OCT and fundus examination are informative, especially false positives which are referred to as subclinical DMO and are at higher risk of developing clinical CSMO.

AUTHORS' CONCLUSIONS

Using retinal thickness thresholds lower than 300 µm and ophthalmologist's fundus assessment as reference standard, central retinal thickness measured with OCT was not sufficiently accurate to diagnose the central type of CSMO in patients with DR referred to retina clinics. However, at least OCT false positives are generally cases of subclinical DMO that cannot be detected clinically but still suffer from increased risk of disease progression. Therefore, the increasing availability of OCT devices, together with their precision and the ability to inform on retinal layer structure, now make OCT widely recognised as the new reference standard for assessment of DMO, even in some screening settings. Thus, this review will not be updated further.