Analysis Of The Area Of Posterior Staphyloma Measured By Optomap And Related Factors

Background:Posterior staphyloma or posterior scleral staphyloma is most common in pathological myopia,causing a variety of blinding myopic maculopathy,with an incidence of 0.7%to 2.05%in the population.In addition to indirect ophthalmoscope,a variety of images can also be recorded,such as ultrasound,three-dimensional magnetic resonance imaging,ultra-widefield fundus imaging,ultra-widefield optical coherence tomography(UWF-OCT)and so on.The optomap is a digital image of the retina produced by Optos scanning laser technology.It is the only technology that can capture 82%view of your retina at one time.In addition to the increase of the axial length,the retinal choroid and sclera becomes thinner,and the shape of the sclera becomes steeper and unsmooth.Another typical change in patients with posterior staphyloma is a gradual increase in the extent.However,the course of the disease is long,and the change of area is not as intuitive as the thickness of the global wall or the degree of steepness,so it may not be enough to describe the area of posterior staphyloma qualitatively.In order to find a more accurate method to measure the area of posterior staphyloma,we use optomap ultra-widefield fundus images to measure it.Objective:To evaluate the effect of measuring the area of posterior staphyloma with optomap ultra-widefield fundus images,and to explore the anatomic abnormalities of the anterior and posterior segment of the eye related to the area of posterior staphyloma.Methods:A cross-sectional study.For the patients with staphyloma after diagnosis,optomap images were obtained by Optos scanning laser technology,and two retinologists used optomap image analysis software to record the boundary of the abnormal pigment along the edge of the posterior staphyloma,supplemented by a smooth curve connected with the abrupt bending point of the blood vessels near the edge of the abnormal pigment as the boundary,and the posterior staphyloma area(PSA)was measured semi-automatically.Intraclass correlation coefficient(ICC)with 95%confidence intervals(CI)was used to identify the repeatability of PSA measurement between and within surveyors.The prevalence,area,LogMAR best corrected visual acuity(BCVA),flat corneal curvature(K1),steep corneal curvature(K2),intraocular pressure(IOP),axial length(AL),center foveal thickness(CFT),subfoveal choroidal thickness(SFCT),subfoveal sclera thickness(SFST),optic disc shape,sex and age were compared among different types of posterior staphyloma.Multiple linear regression analysis was used to find out the independent factors affecting the macular staphyloma area(MSA)(including wide and narrow macular type).Results:A total of 145 posterior staphyloma eyes in 99 patients were evaluated.The average age was 64.52±11.43 years old.The overall average value of PSA measured by the two doctors was 265.77±80.13mm2 and 274.68±82.36mm2,respectively.And the ICC was 0.947(95%CI:0.918～0.965).According to TMDU classification,the wide macular type accounted for the largest proportion of 91.7%,followed by the peripapillary staphyloma of 5.5%,and there was no inferior staphyloma.The smallest area was peripapillary staphyloma only 104.69±28.21mm2(P>0.05).Peripapillary staphyloma was more common than wide macular type in patients with axial length<26.5mm(62.5%vs.7.5%,P<0.0001).In addition,there was no significant difference in the sex ratio between the two types of posterior staphyloma,but both were more female(62.5%vs.66.2%,P>0.05).There was no significant difference in posterior staphyloma area and classification among different optic disc shapes.The average LogMAR BCVA of patients with macular staphyloma was 0.48±0.42(Snellen:0.33),which was higher than that of non-macular staphyloma(P=0.002).The IOP of all patients was within the normal range,with an average of 16.06±2.50mmHg.There was no significant difference in IOP between the two categories of posterior staphyloma.There was no significant difference in K1 between the two groups,but the K2 of macular staphyloma(45.30±2.22D)was higher than that of non-macular staphyloma(43.37±1.40D)(P<0.002).The AL of macular staphyloma was significantly longer,with an average of 29.92±2.46mm,and the thickness of retina,choroid and sclera became thinner in the central fossa(P<0.001).Pearson correlation analysis showed that there was a significant correlation between age and AL in patients with posterior staphyloma(r=-0.345,P<0.0001).The average age of 17 eyes with AL<26.5mm was 72.65±5.59 years old,which was significantly higher than that of the other 128 eyes with AL≥26.5mm(63.44±11.59 years)(P<0.0001).In multiple linear regression analysis,after adjusting CFT,SFCT,SFST,BCVA and K2,the independent factors associated with MSA were AL(β=8.352),gender(β=-26.673)and age(β=1.184).Conclusion:Using optomap ultra-widefield fundus images,the boundary of abnormal pigment at the edge of staphyloma is mainly supplemented by the abrupt bending point of blood vessel at the edge of smooth curve as the boundary,and the method of measuring the area of posterior staphyloma is feasible.There were differences in the area of posterior staphyloma among different types of posterior staphyloma.Eyes with macular staphyloma has a longer axial length,steeper corneal curvature,thinner retinal choroid and sclera in the center foveal,and poorer vision.Posterior staphyloma with AL<26.5mm is more common in older patients.In female,the longer the AL and the older the age,the larger the area of macular staphyloma.