The Effect of Laser Treatment on Macular Pigment of Eye in Cases With Diabetes

Sponsor

Afyon Kocatepe University Hospital (Other)

Overall Status

Completed

CT.gov ID

NCT03150654

Collaborator

(none)

Enrollment

Arm

9.4

Actual Duration (Months)

Study Details

Study Description

Brief 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.

Condition or Disease	Intervention/Treatment	Phase
Diabetic Retinopathy Retinal Degeneration Macula Abnormality Laser Burn of Retina	Device: Laser pan-retinal photocoagulation	N/A

Detailed 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

Study Type:

Interventional

Actual Enrollment :

36 participants

Intervention Model:

Sequential Assignment

Intervention Model Description:

sequential self-controlled clinical trialsequential self-controlled clinical trial

Masking:

None (Open Label)

Primary Purpose:

Treatment

Official Title:

The Effect of Laser Pan-retinal Photocoagulation on Macular Pigment Optical Density in Cases With Diabetic Retinopathy

Actual Study Start Date :

Oct 1, 2015

Actual Primary Completion Date :

Jun 8, 2016

Actual Study Completion Date :

Jul 12, 2016

Arms and Interventions

Arm	Intervention/Treatment
Experimental: Laser pan-retinal photocoagulation Conventional laser pan-retinal photocoagulations were performed by using green laser photocoagulator, every month for 3 months	Device: Laser pan-retinal photocoagulation Green laser photocoagulator Other Names: GYC-500 Vixi

Arm

Intervention/Treatment

Experimental: Laser pan-retinal photocoagulation

Conventional laser pan-retinal photocoagulations were performed by using green laser photocoagulator, every month for 3 months

Device: Laser pan-retinal photocoagulation

Green laser photocoagulator

Other Names:

GYC-500 Vixi

Outcome Measures

Primary Outcome Measures

Change macular pigment optical density from baseline at 6 months [1 month and 3 months]
Macular pigment optical density measures were repeated and recorded at 1st, 2nd, 3rd month before laser treatments and 6th month

Secondary Outcome Measures

Correlation analysis between macular pigment optical density and panretinal laser photocoagulation parameters during 6 months [6 months]
The correlations between macular pigment optical density outcomes and panretinal laser photocoagulation parameters (total energy, total area, total shots, total duration) were evaluated for 6 months

Eligibility Criteria

Criteria

Ages Eligible for Study:

40 Years to 65 Years

Sexes Eligible for Study:

All

Accepts Healthy Volunteers:

Inclusion Criteria:

Best corrected visual acuity (BCVA) logMAR ≤0.4
Newly diagnosis of PDR and initiation of conventional laser PRP treatment
Between the ages of 40 and 65 years (40≤age≤65)

Exclusion Criteria:

Corneal scarring, cataract or intravitreal hemorrhage that prevents appearance of the fundus
Presence of macular pathologies such as AMD or choroidopathy
Presence of macular edema or NVE in the macular area
Detection of macular fluid or edema in OCT or FFA
Previous laser PRP treatments
Focal and / or grid photocoagulation requirements
Previous refractive or vitreoretinal surgery
Spherical refractive error ≥ ±6.00 D or cylinder refractive error ≥ ±3.00 D
Systemic diseases that may affect the choroidal blood flow such as cardiological diseases
Current use of carotenoid supplementation
Changing eating habits
Gastrointestinal diseases that could cause disturbance of dietary absorption