Characteristics Of 30° Central Visual Fields Damage In Severe Myopia

Purpose:To make a 30°central visual fields retrospective analysis on a group of patients with severe myopia(SM) and to offer evidence on the feature of the visual fields in early diagnosis on SM complicating with primary open-angle glaucoma(POAG).Methods:A total of 44 eyes(23 cases)with SM were divided into four Subgroups based on the result of the Glaucoma Hemifield Test(GHT):Group A:'Within normal limits'(16 eyes) GroupB:'Bordine'(5 eyes);GroupC:'Outside normal limits'(13 eyes);GroupD:'General Reduction Of Sensitivity'(10 eyes),they were also divided into four subgroups based on the changes on fundus of eye:GroupI:normal or atrophy of the choroid(8 eyes);GroupⅡ:Ⅰand scleral staphyloma(14 eyes); GroupⅢ:Ⅱand 'lacquer cracks'(7 eyes);GroupⅣ:Ⅲand 'Fuchs spot'and chorioretinal atrophy extensively(15 eyes) The visual fields of all the patients was assessed by an Humphey-750 central 24-2 threshold test.The resulting data were analyzed by SPSS 11.5.The form of visual fields defect in the 'pattern deviation' in different fundus of eyes,the frequency of scotoma and the form of the visual fields defect in sup-nasal,inf-nasal,sup-temple,inf-temple were considered for the analysis,the proporation of the 'absolute scotoma' and the rate of fundus changes consistent with local visual fields defect were also been calculated.Rusults:1.The analysis of variance for subgroups showed a more significant decrease of MD and EL between Group 'whithin normal limit' and Group 'outside normal limit'(P<0.05);No significant variance was showed between the four GHT subgroups of pattern standard deviation(PSD) and diopter(Diop);2.No association was found between GHT and the fundus of eye(p>0.05);3.the frequency of scotoma from high to low were:physiologic blind exaggerated(43.2%),central scotoma(38.64%),nasal step(18.18%),lateral central scotoma(13.64%),annular scotoma(6.82%),arch scotoma(2.27%);4.Local visual fields defect was observed which were fit with the fundus changes in 11 eyes among 13 eyes.The shapes of the visual fields defect were mutiplicity and the verge were distinct.Wedge shape, flange shape and sector defcet in temple field were found.Different types of defect connected with each other:nasal step connected with arch scotoma in temple,cector defct linked with wedge defect and quadrant defect in temple combined with nasal wedge form;absolute scotoma contain 65.02%in all the scotomas;The rate of Visual fields defect connected with physiological blind spot in four different fundus changes are:GroupⅠ(100%);GroupⅡ(71.43%);GroupⅢ(57.14%);GroupⅣ(46.67%); 5.The frequency of scotoma in four different quadrent are: inf-temple(38.74%);sup-temple(25.87%);sup-nasual(19.32%);inf-nasal(16 .07%).Conclusion:These results showed:1.the general reduction of sensitivity become decreased with MD but the amplitude of the MD decreased is larger than the PSD increased.Whether the defect of visual fields is progression are based on MD and PSD been followed up-visit along with time;2.The tendency of GHT to show results 'Outsides normal limits' when the eye length >28.80mm;3.The local visual fields defect usually not connectd with physiological blind spot when chorioretinal atrophy were observed extensively.The fundus changes needed to be found carefully and make a distinction from visual fields defect casued by Glaucoma;4.the frequency of scotoma from high to low are:physiologic blind exaggerated,central scotoma,nasal step,lateral central scotoma and annular scotoma;The shape of scotoma were uniformity which is different from typical arch scotoma;5.The shapes of the visual fields defect were mutiplicity and the verge were distinct.Wedge shape, flange shape and sector defect in temple field were found.Different types of defect connected with each other:nasal step connected with arch scotoma in temple,cector defect linked with wedge defect and quadrant defect in temple combined with nasal wedge form;6.The scotoma occurenced more often in the inferior of the temple quadrants.