Comparison between central corneal thickness and IOP in patients with macrodiscs with physiologic macrocup and normal-sized vital discs.
BACKGROUND
Macrodiscs with physiologic macrocups and elevated intraocular pressure (IOP) are frequently suspicious for glaucoma. Patients with an elevated c/d ratio and an IOP of more than 21 mmHg are often treated for glaucoma. We investigated a possible relationship between macrodiscs, IOP and central corneal thickness.


METHODS
Using the Erlangen glaucoma registry, 341 out of 1,096 consecutive patients with unremarkable and repeated visual field (Octopus 500, G1-3, MD<2.1) were selected. Most of these patients had been sent as glaucoma suspects. The following data were collected: corneal ultrasound pachymetry (Tomey, AL-2000), IOP profile, visual acuity and central corneal power. The morphometric analysis was performed by planimetry using the Littmann formula. Optic nerve heads with a disc area of more than 3.1 mm(2) were defined as macrodiscs.


RESULTS
Patients were subdivided into the following groups: group A: healthy macrodiscs, IOP <22 mmHg (87 patients); group B: healthy macrodiscs, IOP >21 mmHg (66 patients); group C: normal-sized healthy discs, IOP <22 mmHg (93 patients); group D: normal-sized healthy discs, IOP >21 mmHg (95 patients). Mean corneal thickness was: group A: 575+/-36 microm, group B: 596+/-37 microm, group C: 557+/-31 microm and group D: 585+/-38 microm ( P=0.003). Mean central corneal power measured: group A: 41.7+/-1.3 D, group B: 42.4+/-1.3 D, group C: 43.0+/-1.2 D and group D: 42.8+/-1.2 D ( P<0.05). The maximum of IOP was: group A: 17.6+/-3.1, group B: 26.2+/-4.1, group C: 17.2+/-3.4 and group D: 29.7+/-5.5 mmHg. Optic disc size measurements were: group A: 3.91+/-0.66, group B: 3.65+/-0.6, group C: 2.56+/-0.30 mm(2) and group D: 2.39+/-0.39 microm, respectively.


CONCLUSIONS
Macrodiscs with elevated IOP have a higher corneal curvature (mean: +0.7 D) and a thicker central cornea (mean: +21 microm) compared to macrodiscs without elevated IOP. An exact evaluation of optic disc morphology in combination with pachymetric and keratometric measurements in relation to IOP could avoid an overtreatment in patients with suspect primary open-angle glaucoma.
Viestenz
Arne
A
Department of Ophthalmology, University of Erlangen-Nuremberg, Schwabchanlage 6, 91054 Erlangen, Germany. Arne.Viestenz@t-online.de
Wakili
Nina
N
Jünemann
Anselm G M
AG
Horn
Folkert K
FK
Mardin
Christian Y
CY
D016022:Case-Control Studies; D003315:Cornea / Q000000981:diagnostic imaging*; D005654:Fundus Oculi; D005901:Glaucoma / Q000175:diagnosis* / Q000503:physiopathology; D006801:Humans; D007429:Intraocular Pressure; D009798:Ocular Hypertension / Q000175:diagnosis* / Q000503:physiopathology; D009898:Optic Disk / Q000473:pathology*; D010781:Photography; D014463:Ultrasonography; D014794:Visual Fields