title: [Clinical analysis of occult macular dystrophy].
abstract: OBJECTIVE
  To report the clinical features of occult macular dystrophy (OMD).
  
  
  METHODS
  It was a retrospective case series study. 9 cases (14 eyes) with 3 males, 6 females, mean age 36 (7 to 53) years, were examined with vision acuity, fundus ophthalmoscope, fundus fluorescein angiography (FFA), electroretinogram (ERG), visual evoked potential (VEP), multifocal electroretinogram (mfERG) and optical coherence tomography (OCT). In mf ERG, the amplitude density and implicit time of P1 ring1 and ring2 of the affected eyes were compared with the normal control eyes. The correlation between the implicit time & amplitude density of P1 ring1 & ring2 of the affected eyes and visual acuity were examined.
  
  
  RESULTS
  9 eyes VA were 0.05 to 0.2, 4 eyes were 0.3 to 0.6 and 1 eye it was ≥0.7. All of the 9 cases possessed their unique clinical features, including progressive visual decline, normal fundus, FFA, and F-ERG. Macular function impairment was showed only by mfERG. In mfERG, the results of comparison between the affected eyes and normal control eyes were as follows:On implicit time of P1 ring1, average figure of the affected eye group was (27.67±1.07) ms, the control group was (26.28±1.88) ms. The parameters were significant difference between 2 groups (t=-2.308, P<0.05). On ring1 amplitude density, average figure of the affected eye group was (42.71±15.48) nv/deg2, average figure of the control group was (66.79±14.87) nv/deg2, there was also a significant difference between two groups (t=5.259, P<0.05). On implicit time of ring2, average figure of the affected eye group was (27.80±1.20) ms, average figure of the control group was (26.91±0.82) ms, the results from the 2 groups showed significant difference (t=-2.275, P<0.05). On ring2 amplitude density, average figure of the affected eye group was (24.99±8.49) nv/deg2, average figure of the control group was (39.20±6.47) nv/deg2, there was significant difference between two groups (t=4.943, P<0.05). No correlation was found between the implicit time (r=-0.329, -0.369) & amplitude density (r=0.053, 0.057) of P1 ring1 & ring2 of the affected eyes and visual acuity (P>0.05).
  
  
  CONCLUSIONS
  The major signs of OMD are visual acuity decline with normal fundus, FFA and F-ERG, macular function impairment manifested only by mfERG. It's probably a type of cone dystrophy.
authors.affiliation: Beijing Tongren Eye Center, Beijing Tongren Hospital, Capital Medical University, Beijing Ophthalmology & Visual Sciences Key Lab, Beijing 100730, China. continent23@163.com
authors.forename: Guang-lu
authors.initials: GL
authors.lastname: Wang
authors.forename: Li-bin
authors.initials: LB
authors.lastname: Jiang
authors.forename: Xiao-jun
authors.initials: XJ
authors.lastname: Zhang
authors.forename: Ning-li
authors.initials: NL
authors.lastname: Wang
mesh_terms: D000293:Adolescent; D000328:Adult; D016022:Case-Control Studies; D002648:Child; D004596:Electroretinography; D005260:Female; D006801:Humans; D008268:Macular Degeneration / Q000175:diagnosis* / Q000503:physiopathology; D008297:Male; D008875:Middle Aged; D012189:Retrospective Studies; D014792:Visual Acuity; D055815:Young Adult