Clinical Trials Logo

Clinical Trial Summary

It has been hypothesized that thermal damage of laser pan-retinal photocoagulation may affect macular pigment as well as inner layer cells in the retina, so it was aimed to investigate possible effect of conventional laser pan-retinal photocoagulation on macular pigment optical density in diabetic retinopathy patients without macular edema and pathology in this study.


Clinical Trial Description

The local authorized clinical trials ethics committee approved the study and this study was performed following the principles of the Declaration of Helsinki (2008). Detailed information was given to patients about clinical applications and tests, and signed informed consent forms were also obtained from all patients. The 36 eyes of 36 patients, scheduled for laser pan-retinal photocoagulation treatment, with newly diagnosed proliferative diabetic retinopathy without macular edema or scarring between October 2015 - June 2016 were included in this sequential self-controlled clinical trial. Proliferative diabetic retinopathy was diagnosed with determination of neovascular proliferations is either on the disc (NVD) or elsewhere (NVE) except macular area in fundus examination with 90-diopter lens and fundus fluorescein angiography (FFA) (Heidelberg Spectralis, Heidelberg Engineering, Baden-Württemberg, Germany). Patients, detected macular fluid or edema by optical coherence tomography (OCT) (Cirrus HD 4000, Carl Zeis Meditec, CA, USA) in study eye, were excluded in the study. After providing information to patients about the disease and treatment; patients, predicted to show adherence to treatment, were enrolled in the study.

Ophthalmological examinations were performed in all cases. Firstly, visual acuity was recorded, and best-corrected visual acuity (BCVA) assessed using Snellen's chart and was converted to logarithm of the minimum angle of resolution (logMAR) for statistical analysis. After maximal pupil dilatation was achieved using 1% tropicamide and 10% phenylephrine eye drops, put once or twice, at ten minute intervals, slit-lamp examination was performed, and fundus was examined with 90-diopter indirect non-contact fundus lens, and ocular finds were recorded.

Prior to measurements the pupil was dilated to at least 7 mm diameter using a topical mydriatic agent. Macular pigment optical density (MPOD) levels were measured in the study eye using luminance differential thresholds test (MonPack System®, Metrovision, Perenchies, France), color perimetry technique at baseline before first PRP laser treatment and every month before laser treatment until the end of this study. The macular pigment absorbs blue light, and luminance differential thresholds test evaluates the density of the macular pigment by comparing the thresholds of perception of blue light and red light with a staircase technique similar to the technique used in automated perimetry. Luminance differential thresholds were measured for 2 stimuli: a blue stimulus (450-480 nm) absorbed by the MP, and a red one (615 nm) not absorbed. The stimuli were presented at the fovea and at 6 peripheral locations with an eccentricity of 3 to 10 degrees (0°, 0.8°, 1.8°, 2.8° and 3.8°, and the average of two measurements at 6.8° and 7.8° retinal eccentricity serves as the peripheral reference point). Tests parameters were Goldmann size III over a white background of 10 cd.m-2. The average values of the tested (decibel=dB) were converted to logarithm units (log unit) for statistical analysis (dB = 10log10 (Reference1/Reference2)). Because, decibel is always the comparison between two values. As a result, the decibel number is the same, although the measured power value is often different. Therefore, arithmetic operations with the numbers expressed in decibels would be inconvenient.

Conventional laser PRP treatments were performed under topical anesthesia by using green laser photocoagulator (GYC-500 Vixi® Nidek, Gamagori, Japan) and Volk® quadraspheric lens. PRP laser were applied in 300mW power, 200-400-500 μm spot size and 0.1-0.2 second pulse options, based upon preferences and comfort levels. When a pattern array was used, the spot separation was set at 0.5 times the burn width.

Laser parameters were evaluated based on a) area (A) (= πr2 × number of shots) r being the spot radius, which is half of the spot size (100-200-250 μm), and it was converted to square millimeters (mm2) for statistical analyses, b) treatment duration (t) (= 0.1 - 0.2 second × number of shots) and c) total energy (E) (= P × t) milijoules (mJ) P being the power, which is 300mW.

All examinations, MPOD and laser PRP parameters were repeated and recorded at 1st, 2nd, 3rd month before laser treatments and 6th month. Changes in the eating habits of patients were questioned at all study visits. All subjects were told to continue their normal diet, as no subjects were consuming supplements containing lutein or zeaxanthin. ;


Study Design


Related Conditions & MeSH terms


NCT number NCT03150654
Study type Interventional
Source Afyon Kocatepe University Hospital
Contact
Status Completed
Phase N/A
Start date October 1, 2015
Completion date July 12, 2016

See also
  Status Clinical Trial Phase
Completed NCT03660345 - PPV With Internal Limiting Membrane Peeling for Treatment-Naïve DME Phase 3
Completed NCT03660384 - Silicone Oil Versus Gas in PDR Patients Undergoing Vitrectomy N/A
Completed NCT03660371 - ILM Peeling in PDR Patients Undergoing PPV for VH N/A
Completed NCT04905459 - ARDA Software for the Detection of mtmDR
Active, not recruiting NCT04271709 - Manhattan Vision Screening and Follow-Up Study (NYC-SIGHT) N/A
Recruiting NCT03713268 - Intraoperative OCT Guidance of Intraocular Surgery II
Completed NCT05022615 - Comparing 3 Imaging Systems
Completed NCT00385333 - Metabolic Mapping to Measure Retinal Metabolism Phase 2
Recruiting NCT04101604 - Biomarkers of Common Eye Diseases
Completed NCT03702374 - Combined Antioxidant Therapy on Oxidative Stress, Mitochondrial Dysfunction Markers in Diabetic Retinopathy Phase 3
Completed NCT01908816 - An Open-label Extended Clinical Protocol of Ranibizumab to Evaluate Safety and Efficacy in Rare VEGF Driven Ocular Diseases. Phase 3
Completed NCT04009980 - Long-term Retinal Changes After Topical Citicoline Administration in Patients With Mild Signs of Diabetic Retinopathy in Type 1 Diabetes Mellitus. N/A
Completed NCT02924311 - Routine Clinical Practice for Use of Intravitreal Aflibercept Treatment in Patients With Diabetic Macular Edema
Not yet recruiting NCT06257082 - Video-based Patient Education Intervention for Diabetic Eye Screening in Latinx Communities N/A
Not yet recruiting NCT05452993 - Screening for Diabetic Retinopathy in Pharmacies With Artificial Intelligence Enhanced Retinophotography N/A
Withdrawn NCT02812030 - Aflibercept for Retinopathy in the Real World N/A
Completed NCT02391558 - Clinical Evaluation of Noninvasive OCT Angiography Using a Zeiss OCT Prototype to Compare to Fluorescein Angiography N/A
Active, not recruiting NCT02330042 - OCT Biomarkers for Diabetic Retinopathy
Active, not recruiting NCT02353923 - OcuStem Nutritional Supplement in Diabetic Patients With Mild to Moderate Non-proliferative Retinopathy N/A
Completed NCT02390245 - Philadelphia Telemedicine Glaucoma Detection and Follow-Up Study N/A