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Fulltext Retinal laser photocoagulation

Lock JH, Fong KC

Med J Malaysia, 2010 Mar;65(1):88-94; quiz 95.
PMID: 21265262 MyJurnal

Since its discovery in the 1940s, retinal photocoagulation has evolved immensely. Although the first photocoagulators utilised incandescent light, it was the invention of laser that instigated the widespread use of photocoagulation for treatment of retinal diseases. Laser permits choice of electromagnetic wavelength in addition to temporal delivery methods such as continuous and micropulse modes. These variables are crucial for accurate targeting of retinal tissue and prevention of detrimental side effects such as central blind spots. Laser photocoagulation is the mainstay of treatment for proliferative diabetic retinopathy amongst many other retinal conditions. Considering the escalating prevalence of diabetes mellitus, it is important for physicians to grasp the basic principles and be aware of new developments in retinal laser therapy.

Matched MeSH terms: Laser Coagulation/instrumentation; Laser Coagulation/methods*
Fulltext Laser therapy for retinopathy in sickle cell disease

Myint KT, Sahoo S, Thein AW, Moe S, Ni H

Cochrane Database Syst Rev, 2015 Oct 09.
PMID: 26451693 DOI: 10.1002/14651858.CD010790.pub2

BACKGROUND: Sickle cell disease includes a group of inherited haemoglobinopathies affecting multiple organs including the eyes. Some people with the disease develop ocular manifestations due to vaso-occlusion. Vision-threatening complications of sickle cell disease are mainly due to proliferative sickle retinopathy which is characterized by proliferation of new blood vessels. Laser photocoagulation is widely applicable in proliferative retinopathies such as proliferative sickle retinopathy and proliferative diabetic retinopathy. It is important to evaluate the efficacy and safety of laser photocoagulation in the treatment of proliferative sickle retinopathy to prevent sight-threatening complications.
OBJECTIVES: To evaluate the effectiveness of various techniques of laser photocoagulation therapy in sickle cell disease-related retinopathy.
SEARCH METHODS: We searched the Cochrane Cystic Fibrosis and Genetic Disorders Group's Haemoglobinopathies Trials Register, compiled from electronic database searches and handsearching of journals and conference abstract books. Date of last search: 21 September 2015.We also searched the following resources (24 March 2015): Latin American and Carribean Health Science Literature Database (LILACS); WHO International Clinical Trials Registry Platforms (ICTRP); and ClinicalTrials.gov.
SELECTION CRITERIA: Randomised controlled trials comparing laser photocoagulation to no treatment in children and adults.
DATA COLLECTION AND ANALYSIS: Two authors independently assessed trial eligibility, the risk of bias of the included trials and extracted and analysed data. We contacted the trial authors for additional information.
MAIN RESULTS: Two trials (341 eyes of 238 children and adults) were included comparing efficacy and safety of laser photocoagulation to no therapy in people with proliferative sickle retinopathy. There were 121 males and 117 females with an age range from 13 to 67 years. The laser photocoagulation technique used was different in the two trials; one single-centre trial employed sectoral scatter laser photocoagulation using an argon laser; and the second, two-centre trial, employed feeder vessel coagulation using argon laser in one centre and xenon arc in the second centre. The follow-up period ranged from a mean of 21 to 32 months in one trial and 42 to 47 months in the second. Both trials were at risk of selection bias (random sequence generation) because of the randomisation method employed for participants with bilateral disease. One study was considered to be at risk of reporting bias.Using sectoral scatter laser photocoagulation, one trial (174 eyes) reported that complete regression of proliferative sickle retinopathy was seen in 30.2% in the laser group and 22.4% in the control group (no difference between groups). The same trial reported the development of new proliferative sickle retinopathy in 34.3% of laser-treated eyes and in 41.3% of eyes given no treatment; again, there was no difference between treatment groups. The second trial, using feeder vessel coagulation, did not present full data for either treatment group for these outcomes.There was evidence from both trials (341 eyes) that laser photocoagulation using scatter laser or feeder vessel coagulation may prevent the loss of vision in eyes with proliferative sickle retinopathy (at median follow up of 21 to 47 months). Data from both trials indicated that laser treatment prevented the occurrence of vitreous haemorrhage with both argon and xenon laser; with the protective effect being greater with feeder vessel laser treatment compared to scatter photocoagulation.Regarding adverse effects, the incidence of retinal tear was minimal, with only one event reported. Combined data from both trials were available for 341 eyes; there was no difference between the laser and control arms for retinal detachment. In relation to choroidal neovascularization, treatment with xenon arc was found to be associated with a significantly higher risk, but visual loss related to this complication is uncommon with long-term follow up of three years or more.Data regarding quality of life and other adverse effects were not reported in the included trials.
AUTHORS' CONCLUSIONS: Our conclusions are based on the data from two trials conducted over 20 years ago. In the absence of further evidence, laser treatment for sickle cell disease-related retinopathy should be considered as a one of therapeutic options for preventing visual loss and vitreous haemorrhage. However, it does not appear to have a significant different effect on other clinical outcomes such as regression of proliferative sickle retinopathy and development of new ones. No evidence is available assessing efficacy in relation to patient-important outcomes (such as quality of life or the loss of a driving licence). There is limited evidence on safety, overall, scatter argon laser photocoagulation is superior in terms of adverse effects, although feeder vessel coagulation has a better effect in preventing vitreous haemorrhage. Further research is needed to examine the safety of laser treatment compared to other interventions such as intravitreal injection of anti-vascular endothelial growth factors. In addition, patient-important outcomes as well as cost-effectiveness should be addressed.

Matched MeSH terms: Laser Coagulation/adverse effects; Laser Coagulation/methods*
Fulltext Retinal nerve fibre layer thickness changes after pan-retinal photocoagulation in diabetic retinopathy

Goh. SY, Ropilah, AR, Othmaliza, O, Mushawiahti, M

Journal of Surgical Academia, 2016;6(1):4-9.
MyJurnal

Diabetic retinopathy is a disease involving microangiopathic changes in response to chronic hyperglycaemia and pan retinal photocoagulation (PRP) is currently the mainstay of treatment for proliferative retinopathy. In the present study, we evaluated the effect of pan retinal photocoagulation (PRP) on retinal nerve fibre layer (RNFL) thickness in patients with diabetic retinopathy using optical coherence tomography (OCT). This was a prospective longitudinal study. Patients with Type 2 diabetes mellitus with proliferative diabetic retinopathy (PDR) or very severe non-(N)PDR requiring laser treatment were included in the study. PRP was performed by a single trained personnel. Peripapillary RNFL located 3.4 mm around the optic disc was evaluated using time-domain OCT. Examination was performed before treatment, and 2 and 4 months after laser treatment. In total, 39 subjects (39 eyes) were recruited into this study. Twenty-nine patients had PDR and 10 had very severe NPDR. Mean age was 54.97 ± 8.38 years. Male and female genders were almost equally distributed with 18 males and 21 females. Median thickness of average RNFL at baseline was 108.8 um (interquartile range [IQR] 35.3). At two months post-procedure, average RNFL thickness significantly increased to 117.4 (IQR 28.6; P = 0.006). Although, other quadrants revealed a similar trend of increasing thickness at two months but it was not significant. At 4 months post-laser treatment, RNFL thickness in all quadrants reduced to baseline levels with insignificant changes of thickness compared to prior to laser treatment. There was also no significant association between changes in RNFL thickness and HbA1c levels (P = 0.77). In conclusion, PRP causes transient thickening of the RNFL which recovers within 4 months post-laser treatment. At the same time, poor sugar control has no direct influence on the RNFL changes after PRP.

Matched MeSH terms: Laser Coagulation
Fulltext Intravitreal triamcinolone versus laser photocoagulation as a primary treatment for diabetic macular oedema--a comparative pilot study

Norlaili M, Bakiah S, Zunaina E

BMC Ophthalmol, 2011;11:36.
PMID: 22111945 DOI: 10.1186/1471-2415-11-36

BACKGROUND: Diabetic macular oedema is the leading causes of blindness. Laser photocoagulation reduces the risk of visual loss. However recurrences are common and despite laser treatment, patients with diabetic macular oedema experienced progressive loss of vision. Stabilization of the blood retinal barrier introduces a rationale for intravitreal triamcinolone treatment in diabetic macular oedema. This study is intended to compare the best corrected visual acuity (BCVA) and the macular oedema index (MEI) at 3 month of primary treatment for diabetic macular oedema between intravitreal triamcinolone acetonide (IVTA) and laser photocoagulation.
METHODS: This comparative pilot study consists of 40 diabetic patients with diabetic macular oedema. The patients were randomized into two groups using envelope technique sampling procedure. Treatment for diabetic macular oedema was based on the printed envelope technique selected for every patient. Twenty patients were assigned for IVTA group (one injection of IVTA) and another 20 patients for LASER group (one laser session). Main outcome measures were mean BCVA and mean MEI at three months post treatment. The MEI was quantified using Heidelberg Retinal Tomography II.
RESULTS: The mean difference for BCVA at baseline [IVTA: 0.935 (0.223), LASER: 0.795 (0.315)] and at three months post treatment [IVTA: 0.405 (0.224), LASER: 0.525 (0.289)] between IVTA and LASER group was not statistically significant (p = 0.113 and p = 0.151 respectively). The mean difference for MEI at baseline [IVTA: 2.539 (0.914), LASER: 2.139 (0.577)] and at three months post treatment [IVTA: 1.753 (0.614), LASER: 1.711 (0.472)] between IVTA and LASER group was also not statistically significant (p = 0.106 and p = 0.811 respectively).
CONCLUSIONS: IVTA demonstrates good outcome comparable to laser photocoagulation as a primary treatment for diabetic macular oedema at three months post treatment.
TRIAL REGISTRATION: ISRCTN05040192 (http://www.controlled-trial.com).

Matched MeSH terms: Laser Coagulation*
Fulltext Bilateral retinal vein occlusion and rubeosis irides: lessons to learn

Md Noh UK, Ahem A, Mustapha M

Acta Med Iran, 2013;51(9):657-60.
PMID: 24338200

Uncontrolled hypertension is well- known to give rise to systemic complications involving multiple central organs. Artherosclerosis leads to damage of the retinal vessels wall, contributing to venous stasis, thrombosis and finally, occlusion. Retinal vein occlusions compromise vision through development of ischaemic maculopathy, macular oedema, and rubeotic glaucoma. Laser photocoagulation remains the definitive treatment for ischaemic vein occlusion with secondary neovascularization. Timely treatment with anti- vascular endothelial growth factor prevents development of rubeotic glaucoma. We hereby report an unusual case of bilateral retinal vein occlusion complicated by rubeosis irides, which was successfully managed to improve vision and prevent rubeotic glaucoma.

Matched MeSH terms: Laser Coagulation
Prospective Validation of First-Trimester Ultrasound Characteristics as Predictive Tools for Twin-Twin Transfusion Syndrome and Selective Intrauterine Growth Restriction in Monochorionic Diamniotic Twin Pregnancies

Mogra R, Saaid R, Tooher J, Pedersen L, Kesby G, Hyett J

Fetal Diagn Ther, 2020;47(4):321-327.
PMID: 31962341 DOI: 10.1159/000504049

OBJECTIVE: Monochorionic diamniotic (MCDA) twins are at increased risk of adverse outcome due to unequal placental sharing and placental vascular communications between the fetal circulations. Most centres perform ultrasound examination every 2-3 weeks to identify these complications. Identifying a high-risk cohort of MCDA twins in the first trimester would allow more efficient surveillance. We have attempted to validate first-trimester ultrasound characteristics as predictive tools for twin-twin transfusion syndrome (TTTS) and selective intrauterine growth restriction (sIUGR) in MCDA twins.
MATERIAL AND METHODS: This is a prospective cohort study including MCDA twins enrolled at the time of first-trimester combined screening. Differences in crown-rump length (CRL), nuchal translucency (NT) thickness, ductus venosus pulsatility index for veins (DV PIV), presence or absence of tricuspid regurgitation and right ventricular E/A ratio were assessed. Receiver operating characteristic (ROC) curves were used to assess the potential value of these measures as predictive tools for identifying a cohort of MCDA pregnancies at high risk of adverse pregnancy outcome.
RESULTS: Sixty-five MCDA pregnancies were included in the analysis. Nine (14%) developed TTTS, 17 (26%) developed sIUGR. The best predictive marker for TTTS was NT discordance of ≥20% (ROC AUC = 0.79; 95% CI 0.59-0.99). Combining measures did not improve performance (AUC = 0.80; 95% CI 0.62-0.99).
CONCLUSION: NT discordance was the most effective characteristic at predicting TTTS but still had a relatively poor positive predictive value (36%). Intertwin differences in CRL, DV PIV and E/A ratio were not predictive of subsequent pregnancy complications. None of these characteristics have sufficient efficacy to be used to triage MCDA twin pregnancies ongoing obstetric surveillance.

Matched MeSH terms: Laser Coagulation
Pre-Emptive Topical Ketorolac Tromethamine 0.5% for Panretinal Photocoagulation

Chewa Raja JS, Singh S, Ismail F

J Ocul Pharmacol Ther, 2021 Jun;37(5):313-317.
PMID: 33794664 DOI: 10.1089/jop.2020.0089

Purpose: To evaluate the efficacy of topical ketorolac tromethamine 0.5% given pre-emptively a day before, for alleviating pain in patients undergoing panretinal photocoagulation (PRP) treatment. Methods: A controlled single-blinded study was conducted on 33 patients with diabetic retinopathy (DR; severe nonproliferative DR, proliferative DR, or advanced diabetic eye disease) who required PRP treatment in both eyes simultaneously. Each eye of the patients was randomly assigned for ketorolac tromethamine 0.5% eyedrop or placebo. Both eyedrop bottles were randomly labeled. Eyedrops were self-administered by the patients, 4 times a day before the procedure (at 6 am, 12 noon, 6 pm, and 12 midnight) and every 15 min for 1 h (4 times) before the laser. Each patient was subjected to PRP using a Visulas 532s Zeiss device set to spot size 200 μm, time 0.10 s, and ∼600 burns in each eye. The pain score was evaluated immediately after treatment in each eye independently with Scott's visual analog scale (VAS) and the McGill Pain Questionnaire (MPQ). Results: VAS pain score in ketorolac-treated eyes (median 3.0, interquatile range [IQR] ±2.5) was lower than in placebo-treated eyes (median 5.0, IQR ±3.0). Total Pain Rate Index score from MPQ was lower in ketorolac-treated eyes (median 3.0, IQR ±3.0) than in placebo-treated eyes (median 3.0, IQR ±2.5). Both pain score differences are statistically significant with P ˂ 0.05. Conclusion: Topical ketorolac tromethamine 0.5% given pre-emptively a day before is effective in alleviating pain in patients undergoing PRP treatment.

Matched MeSH terms: Laser Coagulation/methods*