[Observation on morphology and function of macular in pathologic myopia].
OBJECTIVE
To observe the morphology and function of the macular in pathologic myopia by the combination of the fundus examination, optic coherence tomography and multifocal electroretinogram (mERG). To analyze the relationships among macular function, ocular axis length, refraction and corrected visual acuity.


METHODS
Case series including 36 eyes of 31 consecutive pathologic myopia cases, which were chosen from Tongren Eye Center from February to April 2006 and divided into two groups according to ocular axis length:group A, composed of 12 eyes from 10 cases (axis length > or = 30.00 mm) and group B, composed of 24 eyes from 21 cases (<30.00 mm). Manifest refraction, A and B scan, fundus examination, OCT scan for the macular area, the measurement of the thickness of the retinal neuroepithelial layer and mERG were carried out for each eyes. The results were further analyzed by comparing the ocular axis length, diopter of myopia, corrected visual acuity, results of the OCT study and mERG. Relationships among the macular function, ocular axis length, refraction and corrected visual acuity were also analyzed.


RESULTS
The mean ocular axis length, diopter of myopia, corrected visual acuity of group A were (31.77 +/- 1.27) mm, (-22.92 +/- 7.10) D and (0.31 +/- 0.25), respectively. The mean ocular axis length, diopter of myopia, corrected visual acuity of group B were (28.64 +/- 1.17) mm, (-14.03 +/- 5.37) D, (0.55 +/- 0.35 ), respectively. Statistically significant difference was shown between these two groups (t = -2.28, P<0.05). The thickness of neural retina of area 1 to 5 in group A was smaller than that of group B, and significant differences exists between these two groups (P = 0.016, 0.032, 0.048, 0.009, 0.002). There were statistical differences in amplitude densities of P1 waves in central macular, super-temporal quadrants, super-nasal quadrants and infer-nasal quadrants between these two groups (t = 3.63, 2.71, 2.21, 2.32, 2.64, P<0.05). Amplitude densities of P1 waves showed negative correlation to ocular axis length (r = - 0.498, P<0.01) and positive correlation to corrected visual acuity (r = 0.468, P<0.01). Ocular axis length showed positive correlation to diopter of myopia (r = 0.800, P<0.01) and negative correlation to corrected visual acuity (r = -0.605, P<0.01). Diopter of myopia was negatively correlated to corrected visual acuity (r = -0.616, P< 0.01).


CONCLUSIONS
Visual function loss in pathologic myopia is correlated with the increase of diopter of myopia, decrease of corrected visual acuity, increased macular disease and decreased macular function and extensive elongation of ocular axis in pathologic myopia. A combination of fundus examination, OCT scan and mERG may contribute to the earlier detection and monitoring of progression of the macular abnormality.
Tu
Ying
Y
Beijing Tongren Eye Center, Beijing Tongren Hospital, Capital Medical University, Beijing 100730, China.
Wei
Wen-Bin
WB
Zhou
Dan
D
Wang
Dong-Sheng
DS
Liu
Yan
Y
Zhao
Ming
M
D000293:Adolescent; D000328:Adult; D005260:Female; D006801:Humans; D008266:Macula Lutea / Q000473:pathology* / Q000503:physiopathology*; D008297:Male; D008875:Middle Aged; D009216:Myopia / Q000473:pathology* / Q000503:physiopathology*; D041623:Tomography, Optical Coherence; D014792:Visual Acuity; D055815:Young Adult