| Central serous chorioretinopathy (CSC) is a condition commonly seen in young or middle aged men as a localized detachment of the neurosensory retina. Although CSC generally resolves without therapy, some patients can also lose visual function with the disease becoming chronic and progressive. So positive treatment is necessary. There are two widely accepted treatment modalities for central serous retinopathy, one is medication and the other is laser photocoagulation. Our study was undertaken to test the efficacy of argon green laser photocoagulation in central serous chorioretinopathy in comparison to medication. At same time, we want to study the value of contrast sensitivity (CS) in diagnosis, following-up and curative effect in CSC. Forty-five CSC patients diagnosed with fundus fluorescence angiography during period between June 2003 and June 2004 were selected for the study. Patients with leakage less than 500 microns away from fovea and other ocular pathology were excluded. They were randomly assigned into 2 groups according to the statistical random table. In group 1 (n=27), the site of leakage was treated with argon green laser (514nm), and in group 2 (n=20), patients were treated with Vitamin C, Vitamin E, Rutin, Difrarel et al. Patients were followed up at intervals of 1, 2, 4, 12 and 24 weeks after treatment. In all patients the following parameters were evaluated before treatment and also during the follow-up period: visual acuity (corrected visual acuity included) on Snellen's acuity chart, tonometry, slit-lamp biomicroscope, fundus examination, fundus fluorescence angiography and contrast sensitivity using Optec3500 Vision Tester. To see the significant difference between the 2 groups at each point we applied "t"test. To see the trend within the group we applied "analysis of variance". P value of 0.05 was considered as statistically significant. The results were showed as follows: 1. The visual acuity in the laser treatment group improved from a pre-laser value of 0.62±0.20 to 0.86±0.21 at 2 weeks and the recovery rate was 96.3% at 1 month following laser treatment, and no patient recrudesced. The recovery rate of contrast sensitivity underthe condition of daytime in the laser treatment group was 70.4% at 2 weeks and 96.3% at 1 month following treatment. In the control group, the visual acuity improved from pre-treatment decimal value of 0.63±0.1 to 0.73±0.21 at 1 month following medication. The recovery rate was 44.4% at 1 month and 61.1% at 3 months following medication. The recurrence rate was 16.7%. The recovery rate of contrast sensitivity under the condition of glare was 11.1% at 2 weeks and 44.4% at 1 month following medication. The difference was statistically significant. 2. In both groups the CSF curve was lower in the affected eyes and there was no statistically significant difference between two groups. The main attenuation was at high frequency ranges and the peak of CSF curve moved to the left. Only when the visual acuity declined severely(≤0.5), the low frequency range were involved. Above all, CS under the daytime condition was better than that under the nighttime condition. At the recovery stage, CS at low frequency ranges was in the first place, media frequency ranges was in the next place and the high frequency ranges was final. Even if the patients had no symptoms, macular edema disappeared and the leakage was sealed, part of CS showed delayed recovery. The laser photocoagulation bringsabout a faster quantitative and qualitative visual recovery in comparison to medication in eyes with CSC. Studies performed with indocyanine green angiography in cases of CSC have reported that hperpermeability of choroidal vessels could be the primary pathology in CSC and retinal pigment epithelial(RPE)abnormality is secondary to it. That the development of one or more areas of retinal pigment epithelial defects and subsequent focal leakage leads to serous fluid retention in the subretinal space and subsequent serous detachment of the neurosensory retina. Destroying the lost compensation retinal pigment epithelial cells, activating natural cells hyperplasia to cover with facula and forming well-balanced blood-retina barrier is one side of mechanisms of laser photocoagulation on CSC. The other side is improving the blood circulation in choriocapillaries and forming new fluid channels. So it can reduce the fluid overload over the pigment epithelial layer. In the present study, vast observations are suggestive that laser photocoagulation can seal the site of leaking, protect visual function, hasten resolution and reduce recurrence. Accidentally injuring macula lutea and developing subretinal neovascularizationfollowing laser treatment for CSC have been described earlier in literature. However, as long as the orientations of leaking are exact, preferences are in order and operations are correct, the complications can be avoided completely and in our study none of the patients developed the complications. As far as recurrence concerned, the viewpoints of scholars are controversy. Our study approved that the recurrence was significantly decreased in comparison to the medication group. In the past, majorities of scholars only used visual acuity to evaluate the curative effect in CSC. However, the symptoms of lots of patients are when they look at objects, the colors, the shapes and the distances changed while their focus visual acuity is up to stuff. Even if after the treatments the declined visual acuity gets back, the patients also have the above-mentioned symptoms. The task of the visual system is to enable the localization and identification of objects seen against backgrounds. Their localization involves discrimination of luminance, shapes, colors and textures, that is, it involves the ability to see changes in these attributes. Human spatial vision has been optimized to detect small changes in thestimuli. Contrast sensitivity (CS) is thus one of the most important attributes of the visual system. In clinical practice, vision is most commonly evaluated in terms of the ability to identify the visual symbols at the highest contrast. However, this does not take into account the sensitivity to low contrasts. The spatial luminance contrast sensitivity function ( CSF ) gives us a more complete representation of the spatial processing capacity of the visual system than the measurement of the visual acuity at maximum contrast. Alterations of the CSF related to several pathologies have been found not to affect the visual acuity of CSC patients. So Contrast sensitivity is a more sensitive test enabling subtle defects or improvements to be detected centrally in the early stages of disease and it plays a key role in diagnosis, following-up and evaluation of curative effect in CSC. Our conclusion is that to treat the CSC with laser especially at early stage of the disease can significantly hasten recovery , improve visual acuity,protect visual function and reduce recurrence rate. Contrast sensitivity makes important sense in diagnosis and... |
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