Use of smartphones for detecting diabetic retinopathy: a protocol for a scoping review of diagnostic test accuracy studies.

INTRODUCTION: Diabetic retinopathy (DR) is a common microvascular complication of diabetes mellitus and the leading cause of impaired vision in adults worldwide. Early detection and treatment for DR could improve patient outcomes. Traditional methods of detecting DR include the gold standard Early Treatment Diabetic Retinopathy Study seven standard fields fundus photography, ophthalmoscopy and slit-lamp biomicroscopy. These modalities can be expensive, difficult to access and require involvement of specialised healthcare professionals. With the development of mobile phone technology, there is a growing interest in their use for DR identification as this approach is potentially more affordable, accessible and easier to use. Smartphones can be employed in a variety of ways for ophthalmoscopy including the use of smartphone camera, various attachments and artificial intelligence for obtaining and grading of retinal images. The aim of this scoping review is to determine the diagnostic test accuracy of various smartphone ophthalmoscopy approaches for detecting DR in diabetic patients. METHODS AND ANALYSIS: We will perform an electronic search of MEDLINE, Embase and Cochrane Library for literature published from 2000 onwards. Two reviewers will independently analyse studies for eligibility and assess study quality using the QUADAS-2 tool. Data for a 2⨉2 contingency table will be extracted. If possible, we will pool sensitivity and specificity data using the random-effects model and construct a summary receiver operating characteristic curve. In case of high heterogeneity, we will present the findings narratively. Subgroup analysis and sensitivity analysis will be performed where appropriate. ETHICS AND DISSEMINATION: This scoping review aims to provide an overview of smartphone ophthalmoscopy in DR identification. It will present findings on the accuracy of smartphone ophthalmoscopy in detecting DR, identify gaps in the literature and provide recommendations for future research. This review does not require ethical approval as we will not collect primary data.

Effect of bilateral sequential cataract extraction on intraocular pressure in non-glaucomatous Asian eyes.

BACKGROUND/AIMS: To determine the effect of cataract extraction on intraocular pressure (IOP) of both eyes in patients undergoing sequential cataract extractions. METHODS: Retrospective review of 116 consecutive treatment-naive non-glaucomatous patients who underwent sequential cataract extractions of bilateral eyes. Baseline and postsurgical IOP measurements of eyes after cataract extraction were reviewed. Postsurgical IOP of the first surgical eye was compared with the IOP of the (unoperated) second eye. RESULTS: Before surgery, there was no significant difference between the mean IOP of both eyes (15.4±2.6 mm Hg vs 15.2±2.5 mm Hg, p=0.22), and good correlation of presurgical IOP in both eyes was observed. After surgery, mean IOP in the first surgical eye decreased to 14.0±3.1 mm Hg at 1 month (p≤0.001). There was sustained and statistically significant (p<0.001) decrease in IOP in that eye for 2 years. Mean decrease in IOP ranged from 1.6 (8.6%) to 2.3 mm Hg (14.0%). In contrast, the IOP in the fellow (non-surgical) eye remained unchanged. Subsequently, cataract surgery to the fellow eye resulted in a decrease in IOP to a level similar to that of the previously operated eye, which was similarly sustained. Presurgical IOP was the only factor affecting the magnitude of decrease in IOP. CONCLUSIONS: There is sustained decrease in IOP after cataract extraction in non-glaucomatous eyes. This decrease is of greater magnitude in eyes with higher presurgical IOP and is not affected by the type of surgery performed. The effect of IOP decrease after surgery is unilateral and does not affect the fellow eye.

Comparison of choroidal thicknesses using swept source and spectral domain optical coherence tomography in diseased and normal eyes.

BACKGROUND/AIMS: Choroidal thickness measurements are reported to differ between swept source optical coherence tomography (SS-OCT) and spectral domain OCT (SD-OCT). This study aimed to assess the comparability of choroidal thickness measurements using SS-OCT and SD-OCT devices among patients with retinal diseases and normal participants. METHODS: In a prospective cohort study of 100 subjects, comprising patients with retinal disease and normal volunteers, OCT scans were performed sequentially with the DRI OCT-1 and Spectralis OCT using standardised imaging protocols. Subfoveal choroidal thicknesses were independently measured by masked reading-centre certified graders. Paired t tests and intraclass correlation coefficients (ICCs) were used to compare the measurements. RESULTS: Among all 100 participants, mean subfoveal choroidal thickness was 264.3 µm and 272.4 µm for DRI OCT-1 and Spectralis OCT respectively (p=0.001), with ICC of 0.989. The mean difference in choroidal thickness between OCT devices was larger among eyes with retinal diseases compared with normal eyes (8.4 µm vs 7.3 µm). Eyes with choroidal thickness ≤200 µm had smaller differences between OCT devices compared with those with thicker choroids (mean 3.6 µm vs 10.0 µm, p=0.021). CONCLUSIONS: Subfoveal choroidal thickness measurements are comparable between DRI OCT-1 and Spectralis OCT. The presence of retinal disease increases the variability of choroidal thickness measurements between OCT devices.

Macular choroidal thicknesses in healthy adults--relationship with ocular and demographic factors.

PURPOSE: To determine the differences in choroidal thickness (CT) among different groups of refractive errors and axial lengths, and to describe the rates of change of CT with ocular and demographic factors in various regions of the macula. METHODS: Prospective cohort study of 150 healthy volunteers. Spectral-domain optical coherence tomography was performed on both eyes using a standardized imaging protocol. Manual grading of the choroidal boundaries was independently performed by trained graders to determine Early Treatment Diabetic Retinopathy Study (ETDRS) subfield choroidal thickness. Multiple linear regression analyses were performed to determine the effects of spherical equivalent, axial length and age on choroidal thickness in each subfield. RESULTS: The mean central subfield CT was 324.9 µm (range, 123-566 µm) and varied significantly with both spherical equivalent (P < 0.001) and axial length (P < 0.001), but not age or sex. On multiple linear regression analysis using spherical equivalent, the coefficients were 20.0 for the central subfield, ranged from 16.9 to 19.9 for the inner subfields, and decreased to 13.9 to 16.2 for the outer subfields. Performing regression analysis using axial length, the coefficients were -36.4 for the central subfield, -30.5 to -34.5 for the inner subfields, and -24.6 to -27.3 for the outer subfields. CONCLUSIONS: Choroidal thickness varies significantly with spherical equivalent and axial length in all regions of the macula, but exhibits different rates of change among different subfields. The rates of change were greater in the central and inner subfields compared with the outer subfields.

A novel classification of the vascular patterns of polypoidal choroidal vasculopathy and its relation to clinical outcomes.

PURPOSE: To propose a novel classification system for polypoidal choroidal vasculopathy (PCV), and compare the clinical outcomes among PCV subtypes. METHODS: Consecutive treatment-naive patients with symptomatic PCV were managed over 5 years. PCV subtypes were classified based on indocyanine green angiography (ICGA) and fluorescein angiography (FA) characteristics. RESULTS: Among 107 patients, 3 PCV subtypes were seen: Type A (interconnecting channels on ICGA) -22.4%; Type B (branching vascular network with no leakage) -24.3%; Type C (branching vascular network with late leakage on FA) -53.3%. The proportion of patients with best-corrected visual acuity (BCVA) ≥20/40 was highest in Type A, intermediate in Type B and lowest in Type C at all time points (80% vs 66.7% vs 7.7% at 5 years, p<0.001). The highest rate of moderate visual loss (loss of ≥3 lines) occurred in Type C PCV (57.7% vs 0% for Types B and A at 5 years, p<0.001). Risk factors for poor visual outcomes were PCV subtype (OR 53.7, p<0.001 for Type C and OR 13.7, p=0.023 for Type B compared to Type A) and age (OR 1.06, 95% CI 1.002 to 1.125, p=0.044). CONCLUSIONS: The PCV subtype seen on initial presentation affects the long-term visual outcomes over a 5-year period.