Ophthalmological society reported that approximately 21.7% of patients with diabetes had DR 2 . Macular oedema increases 3% in moderate NPDR, 38% in severe NPDR and 71% in PDR. Epidemiological studies and clinical trials have shown that Diabetic macular edema results in irreversible loss of vision and is the major cause of visual morbidity in patients with Diabetes of adult onset. To date, the most effective means to reduce the risk of vision loss from DME includes focal/grid laserphotocoagulation and intensive blood sugar control. In Early Treatment Diabetic Retinopathy study (ETDRS), Focal/Grid Laserphotocoagulation of eyes with diabetic macular edema (DME) reduced the risk of moderate visual acuity loss (defined as a loss of 15 or more letters) by approximately 50%. One of the major findings
Summary: The authors evalute the visual functions of patients with unilateral central serous chorioretinopathy (CSC) and compare them with their non-affected eye and with a control group. Fourteen patients with CSC treated with direct laser- photocoagulation were examined preoperatively and followed-up, up to 2 years postoperatively. Baseline best corrected vi- sual acuity (BCVA) and contrast sensitivity (CS) of both eyes of patients was significantly lower in comparison with the controls. BCVA and CS in affected eyes were significantly lower compared to the fellow eye of patients. The final BCVA and CS of patients did not differ significantly from the controls, except CS of affected eyes in the spatial frequency of 3.69 c/deg. Two years after laser treatment, there were only nonsignificant differences of both photopic full-field electroretino- graphy (phERG) and multifocal electroretinography (mfERG) responses between the treated, the nonaffected eye of the patients and the control group with exception of a significantly longer P1 implicit time in the parafoveolar region in af- fected eyes. Colour discrimination was normal in 85.8% of affected eyes of the patients. Despite a significant improvement of macular function in CSC eyes, functional examination methods do not prove complete resolution of function 2 years after laser-treatment.
Laserphotocoagulation is a generally safe option for RAM treatment. In our study, we did not meet any laser-related complications. In spite of the limited study population, this fact confirms that laser photocoagula- tion could be the primary option for RAM treatment. However, tissue-sparing approaches and, primarily, anti- VEGF therapy  affords a dynamic of decreasing risk for collateral retinal damage. Nevertheless, anti-VEGF therapy is not without its disadvantages since it includes invasive manipulations and typically needs repetitive procedures, as well as not guaranteeing complete reso- lution of the RAM. Subthreshold laser treatment as an alternative tissue-sparing option demonstrated efficacy similar to conventional laserphotocoagulation without attendant adverse effects . However, it is worth noting that although the authors reported no detectable signs of the treatment at the laser application site, nevertheless the calculated total laser energy was quite high (at least of 0.06 vs 0.02 mJ/pulse in our study).
This is to certify that the dissertation entitled, “A STUDY ON CLINICAL OUTCOMES OF LASERPHOTOCOAGULATION FOR PREMATURE RETINOPATHY” submitted by Dr.MALATHI.V.K, in partial fulfillment for the award of the degree of Master of Surgery in Ophthalmology by The Tamil nadu Dr.M.G.R.Medical University, Chennai is a bonafide record of the work done by her in the Regional Institute of Ophthalmology, Government Ophthalmic Hospital, Egmore, Chennai, during the academic year 2010-2013.
This noncomparative prospective consecutive interventional case series was performed at the L V Prasad Eye Institute, Hyderabad, India from January 2013 to June 2013. Prior approval from the Institutional Review Board was taken and informed consent was obtained from each study subject. This study was conducted in accordance with the tenets of the Declaration of Helsinki. Inclusion criteria included adults 18 years old. Nonresolving CSCR was defined as: persistent CSCR with a duration of 3 months or more; center-involving neurosensory detachment with minimum best-corrected visual acuity (BCVA) of 20/200 or better in the study eye; fellow eye vision loss due to CSCR; and presence of active angiographic leakage in fluorescein angiography. Exclusion criteria included: any previous treatment for CSCR in the study eye; CSCR with subfoveal leak for which laserphotocoagulation may not be the treatment of choice; cur- rent oral/topical steroid exposure, which may be necessary for any systemic illness; decrease in visual acuity due to causes other than CSCR; history of intraocular surgery in the study eye or anticipated within the next 6 months following day 1; prior panretinal laserphotocoagulation or macular laserphotocoagulation in the study eye; history of allergy to fluorescein used in fluorescein angiography; myopia of more than - 6.0 diopters; Cushing’s disease; renal diseases; pregnancy and breastfeeding; and inability to obtain fundus photographs or fluorescein angiograms of sufficient quality to be analyzed by the site.
This is to certify that this dissertation entitled “STUDY OF THE EFFECT OF GRID LASERPHOTOCOAGULATION ON CONTRAST SENSITIVITY IN DIABETIC MACULAR ODEMA ” is a bonafide record of the research work done by Dr. RAMYA.M., post graduate in Regional Institute of Ophthalmology Government Ophthalmic Hospital, Madras Medical College and Research Institute, ,Chennai-03, in partial fulfillment of the regulations laid down by The Tamil Nadu Dr.M.G.R. Medical University for the award of M.S. Ophthalmology Branch III, unde r my guidance and supervision during the academic years 2009-2012.
THUNDERBIRD study tested the hypothesis that there is a synergistic effect of IVTA and laserphotocoagulation on vision improvement and reduction in macular thickness in eyes with DME. The study was conducted in accordance with the Declaration of Helsinki and was approved by the Research Ethics Committees of the four participating clinical centers. Patients were included in the THUNDER- BIRD study if they had focal or diffuse DME involving the central fovea with a CMT of greater than 250 µ m and best-corrected logarithm of minimum angle of resolution letters read (ie, best-corrected visual acuity [BCVA]) in the affected eye(s) of 17–70 letters. Time-domain optical coherence tomography was performed (Stratus OCT™; Carl Zeiss Meditec, Jena, Germany) to determine the aver- age thickness of the central macula (1 mm diameter). Eyes were allocated either to IVTA injection or sham-injection 6 weeks prior to laserphotocoagulation. Eyes assigned to IVTA received an intravitreal injection of 0.1 mL of Kenacort ® 40 (40 mg/mL triamcinolone acetonide; Bristol-
Macular laserphotocoagulation therapy was performed using contact lens and double coupling frequency Nd:Yag (neodymium-doped yttrium aluminium garnet) laser. Grid laserphotocoagulation was performed at 500–3,000 µ m from central fovea with 50–100 µ m spot size, time of exposure 0.05–0.1 seconds, moderate burn intensity, and the distance between spots is 1–2 spots. Subjects treated with laser photo- coagulation therapy were reexamined 1 week, 1 month, and 3 months posttreatment. During 1-month and 3-month fol- low-up, OCT was performed to measure macular thickness.
This study was performed to evaluate the functional and anatomic outcomes of focal macular laserphotocoagulation in eyes with non-center involved macular edema (non-CI ME). Forty-nine eyes of 43 patients with non-CI ME were included. Focal macular laserphotocoagulation was conducted on twenty- nine eyes of 25 patients, while 20 eyes of 18 patients with non-CI ME were followed without treatment and served as the control group. Data relating to best corrected visual acuity (BCVA; Early Treatment Diabetic Retinopathy Study) and central subfield thickness (CST), inner zone thickness (IZT), outer zone thickness (OZT), and total macular volume (TMV) as determined by optical coherence tomography (OCT) were collected and compared between the groups. At 12 months, VA decreased by a mean of 0.4 letters in the treatment group and 3.3 letters in the control group (p=0.03). Gain in VA ≥5 letters was noted in 6 (21%) of the eyes in the treatment group versus 1 (5%) eye in the control group (p=0.12). At 12 months, average IZT decreased by 22.6 microns in the treatment group and increased by 10.9 microns in the control group (p<0.001). The treatment group revealed significant reduction in CST, average OZT, and TMV as compared to the control group at 12 months (all p<0.05).Generally, focal laserphotocoagulation may have more favourable visual outcomes in this specific group of diabetic patients than does observation. In addition, focal laser treatment provided better outcomes with improvement in OCT parameters as compared to the control group.
information about the leaking areas within the macular area responsible for thickening of the retina, SD-OCT shows those thickened areas in the map resulting from leakage of vessels. We hypothesized that effective macular laser photocoagu- lation can be applied, obtaining indirect information of the points where macular laser treatment should be precisely placed utilizing SD-OCT, without exposing the patient to the potential risks of FA and with an image acquisition pro- cess that takes a few seconds. The aim of this study was to compare the efficacy of SD-OCT and FA in the guidance of macular laserphotocoagulation for the treatment of diabetic macular edema.
Laserphotocoagulation can be applied to the retina via several routes. The most common is transpupillary laser either performed on slit lamps through specialised contact laser lenses, or with binocular indirect ophthalmoscopy through non-contact lenses. The latter is useful for peripheral retinal lesions as this apparatus offers a wider field of view. Laser can also be transmitted via fibreoptics to an endolaser probe for intraocular delivery during vitreoretinal procedures. Contact probes are also available for trans-scleral application. In recent years, ophthalmologists have been offered a choice of temporal modes for laser delivery. Currently the majority of retinal photocoagulation is achieved using continuous mode: Laser is emitted at a sustained energy level for a given period of time, usually between 100-200ms (Figure 4-B) 6 . The
In the base-case analysis, if PRP treatment were delayed until HR-PDR developed, this was more costly and less effective than if PRP treatment were administered to patients with severe NPDR (see table 3). Treating earlier with PRP laser meant that fewer people in the intervention arm compared with the usual care arm progressed to more advanced stages of DR. The uncertainty in the results is shown in the cost-effectiveness plane (figure 1A). If a decision maker is willing to pay between £20 000 and £30 000 per QALY, there is a 60% probability that early PRP is more cost-effective than usual care (figure 1B).
We found that additional laser therapy may control re current neovascularization in most of the cases (46.4%), but ultimately, some of them ( 11.6%) may need vitrectomy. Spitznas et aI., 4 reported that by photocoagulation, in 9 1 % of the patients, the disease could be brought to a morpho logical standstill over a mean observation time of 5 years after completion of treatment. They also reported that vi sual acuity remained unchanged or improved in 87% of the
Respiratory rates were performed after the methods of Travis where rats were placed in a commercially available perspex holding chamber (Travis et al., 1979). Spontaneous breathing rates were recorded on video camera. Rats were able to walk in to this cylindrical chamber, there was no impediment to breathing by the chamber walls, and there were a number of holes to allow free entry of room air. The rats stood facing a plastic cone within the chamber which communicated with room air. Each rat was acclimatised to the cham ber in three sessions of two minutes each. D uring these acclimatisation sessions the rats often attempted to turn around in the narrow cylindrical chamber and the breathing was erratic as a result. However in subsequent sessions they were content to stand in a forward facing direction and the breathing was more regular allowing rates to be counted. By videotaping the rats breathing, episodes of m ovement and sniffing could be differentiated from normal breathing and these were not recorded. Recordings based on pressure changés in the chamber do not allow for this differentiation. After allowing 30 seconds for the rats to settle in the chamber, 30 seconds to one minute of the rats' breathing was recorded. The mean of two separate recordings for each rat was taken at each timepoint. For both ILP and PDT recordings were made in 8 rats before treatment as a control and after treatment at 1 week, 2 weeks, 3 weeks, 4 weeks, 6 and 8 weeks. Assessments at 4 and 6 months were made in separate groups of at least 6 animals which did not have control measurements taken before treatment. These rats were compared to controls which had a sham operation, that is, a general anaesthetic with a chest wall incision and insertion of the laser fibre only without activation of the laser. These controls were kept out to 4 and 6 months respectively.
At higher energies (4000J), the necrotic lesions were uncontrolled and unpredictable with the metal needle, the main cause of this being the fibre cladding burning back within the needle, the light then leaking from the sides of the fibre, resulting in further burning of cladding - the heat was therefore being propagated back up the fibre in a variable fashion. With the bare fibre at 8W, a fairly uniform, large volume necrotic lesion was produced, but the cladding was again burnt back up to the liver capsule. The fibre used had hard polymer cladding which is more prone to burning at high temperatures than a silica clad fibre. The latter, therefore needs to be evaluated in a similar study, but the buffer coat/jacket should be removed over a long length since this may also burn. A further simple experiment was performed in air, comparing the silica clad and polymer clad fibre; the fibre-tip was placed in the centre of a 19 gauge steel needle, and the laser (805nm) activated at 8W. The surface of the needle could be seen to be heating, and as expected with the polymer clad fibre, the heat rapidly propagated back up towards the hub o f the needle, and on withdrawing the fibre the cladding was heavily burnt. With the silica clad fibre, heat was seen to propagate equally forwards and backwards, the total length of heated needle being 26mm, remaining like this from 20s to 200s - the tip of the fibre was only slightly damaged. This shows that silica clad fibres may give a more predictable necrosis when used inside metal needles for ILP, although steel needles may not be ideal since one would expect significantly less conduction of heat along the needle in vivo, and so the subsequent necrosis may not differ much from a bare silica clad fibre. Therefore, needles with greater thermal conductivity than steel (eg. copper) should also be evaluated, to try to get longer, broader necrosis at high laser powers.
However, the evaluation has various shortcomings. First and most notably is the use of progression data mainly from the ETDRS trial. 6 More recent studies have been conducted but they have not addressed the issue of early versus delayed PRP (timing). Due to improved treatments, better blood glucose control and population screening, monitoring and intervention, there has been a reduction in the incidence of severe vision loss/blindness from DR. 2 4 Second, even though we conducted a thorough search of the literature, we did not identify any studies with health state utility values by the detailed severity levels that we have in our model or data on disutilities associated with progressing through all the different stages of DR, or data on the disutilities after PRP, especially following the use of modern laser delivery devices. We had to rely heavily on two papers 9 10 to characterise the different visual acuity levels into health states and link them to the utility values for patients with DR as reported in Brown et al . 8 The key limitation from this
dense. This is evident at light microscopy as nuclear pyknosis and celluar hyperchromasia, thermally damaged epithelial cells become elongated and spindled perhaps due to collapse of the cytoskeleton. The main difference between the irreversible cell death caused by higher temperatures and the reversible cell damage seen at lower temperatures is that in the former structural cellular damage is evident immediately after treatment whereas with the latter it may be 48-72 hours before the full extent of tissue damage is evident(Thomsen, 1991). As tissue temperatures approach the threshold temperature of vapourisation of water(100®C) tissue water(which accounts for about 80% of the constituents of soft tissue) boils resulting in steam bubble formation within the tissue(Brackett et al 1986), the bubbles enlarge and eventually rupture explosively resulting in mechanical disruption of cells. Steam escapes along tissue planes into adjacent blood vessels( a phenomenon which can be seen during ILP treatment when monitored in real time with ultrasound). Water strongly absorbs light at wavelengths over 1300nm with the water absorption peaks occuring at around 1450 and 1950nm in most tissues except fat(Blanc and Colies ,1990). In addition, the main determinant of the thermal conductivity of a tissue will be the tissue water content. Once the available tissue water dessicates then both the optical and thermal properties of the tissue change. The temperature rises rapidly up to 300-400®C resulting in carmelization, carbonisation and tissue combustion leading to cavitation, char formation and the production of smoke. The mechanisms of tissue ablation are not well understood but are probably due to thermal breakdown of tissue elements and molecular bonds(Thomsen,1991). Once charring has occured then obviously the transmission of light from the laser fibre into the surrounding tissue decreases significantly and the damage to the tissue occurs by means of thermal conduction with the fibre tip acting as a point heat source(Wyman et al, 1992, Amin et al, 1993). The importance of charring is discussed in the section on the experimental work(see section 4.7.3).
Optic disc pit (ODP) is a rare congenital anomaly of the optic disc, which can be complicated by a maculopathy asso- ciated with progressive visual loss. Optic disc pits are usually unilateral and sporadic in occurrence, and the develop- ment of maculopathy is unpredictable with no known triggers. Optic disc pit maculopathy (ODP-M) is characterized by intraretinal and subretinal fluid at the macula, causing visual deterioration. The source of this fluid is still unclear, and several competing theories have suggested it may be vitreous fluid, cerebrospinal fluid, leakage from blood ves- sels at the base of the pit or leakage from the choroid. The mechanism of pathogenesis of ODP-M has not been fully elucidated, but vitreous liquefaction and traction and pressure gradients within the eye have been implicated to be involved. There are no clear guidelines on the management of patients with ODP-M, and numerous techniques have been described, including laserphotocoagulation, intravitreal gas injection, macular buckling and pars plana vitrec- tomy with many different modifications. The majority of reports describe small series, and as there are no comparative studies there is no consensus regarding the optimal treatment for ODP-M. This review discusses the literature on the possible sources of fluid and mechanisms of pathogenesis in ODP-M, as well as the wide array of treatment modali- ties and their results. Based on these, a set of recommended key concepts for the timing and choice of treatment for these challenging are presented.
DOI: 10.4236/ojoph.2019.92009 77 Open Journal of Ophthalmology letters compared to 33.3% in the (sh/bz) group. Mean decrease CRT was 435 μm and 404 μm in the bz/bz and sh/bz group respectively. Study concluded IVB given every 6 weeks for 12 months improves VA and reduce ME significantly, while delayed treatment may limit visual improvement.  . A study eva- luated 1-year efficacy and safety of low-frequency IVB in treating ME due RVO. Patients with CRVO (n = 33) and BRVO (n = 55) were included. After 1 month, BCVA and OCT were recorded. If <30% improvement in BCVA and CMT, two injections were added at 1.5-month intervals. others were injected as per need. After a year 74% had clinically significant improvement of BCVA (>0.3 log MAR) with 1.98 average number of injections. Both groups had clinically signif- icant mean BCVA improvement from baseline vision and decrease in CMT. Pan retinal laserphotocoagulation was done in 75.8% of all eyes with CRVO and sectoral photocoagulation in 49.1% of eyes with BRVO .
• Focal laserphotocoagulation is indicated for patients with clinically significant macular oedema; it targets micro aneurysms near the macula, reducing the plasma leakage responsible for intra retinal swelling. The Early treatment Diabetic Study showed that focal laserphotocoagulation reduces the risk of moderate vision loss by 50-70% in patients with macular oedema. 12