The optic nerve head in myocilin glaucoma.
OBJECTIVE
Approximately 1 in 30 unselected patients with open-angle glaucoma (OAG) have a mutation in the myocilin gene. The purpose of this study was to describe the morphologic features of the optic nerve head (ONH) in myocilin glaucoma.


METHODS
A case-control design was adopted. Sixty-six patients heterozygous for a range of myocilin mutation (cases) were matched in disease severity to 105 patients with OAG known not to have a myocilin mutation (controls), using visual field findings. Quantifiable analysis of the ONH was undertaken of stereoscopic photographs, by using custom software with a z-screen. Subjective grading of the cup depth, lamina cribrosa pore shape and orientation, and the slope of the neuroretinal rim was performed by an examiner masked to the subject's mutation status. Mutation screening was conducted using either direct sequencing or single-stranded conformation polymorphism analysis.


RESULTS
Patients with a myocilin mutation had glaucoma diagnosed earlier (P < 0.001) and had higher maximum recorded intraocular pressures (P < 0.001) than did the control OAG subjects. There was no significant (P > 0.05) difference in global disc area, global neuroretinal rim area, alpha-parapapillary atrophy, beta-parapapillary atrophy, slope of neuroretinal rim, or visible lamina cribrosa morphology between myocilin mutation carriers and patients with nonmyocilin glaucoma. Disc hemorrhages were identified more frequently in those without mutations (14/209 vs. 1/129), though this was not significant after correction for multiple hypothesis testing.


CONCLUSIONS
No major structural or morphologic difference of the ONH was detected in pooled data from subjects who had myocilin mutations compared with data from individuals with nonmyocilin glaucoma.
Hewitt
Alex W
AW
Department of Ophthalmology, Flinders University, Adelaide, Australia.
Bennett
Sonya L
SL
Fingert
John H
JH
Cooper
Richard L
RL
Stone
Edwin M
EM
Craig
Jamie E
JE
Mackey
David A
DA
D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D016022:Case-Control Studies; D003598:Cytoskeletal Proteins / Q000235:genetics*; D004252:DNA Mutational Analysis; D005136:Eye Proteins / Q000235:genetics*; D005260:Female; D005902:Glaucoma, Open-Angle / Q000175:diagnosis* / Q000235:genetics*; D006023:Glycoproteins / Q000235:genetics*; D006801:Humans; D007429:Intraocular Pressure; D008297:Male; D008875:Middle Aged; D009154:Mutation; D009898:Optic Disk / Q000473:pathology*; D009901:Optic Nerve Diseases / Q000175:diagnosis* / Q000235:genetics; D016133:Polymerase Chain Reaction; D018807:Polymorphism, Single-Stranded Conformational; D000099179:Myocilin
D003598:Cytoskeletal Proteins; D005136:Eye Proteins; D006023:Glycoproteins; D000099179:Myocilin