Posterior pole retinal thickness in ocular hypertension and glaucoma: early changes detected by hemispheric asymmetries.
OBJECTIVE
To evaluate retinal thickness at the posterior pole of the fundus in ocular hypertension (OHT) and open-angle glaucoma (OAG), and to correlate morphometric findings with visual sensitivity as determined by automated perimetry.


METHODS
One randomly selected eye from 41 patients with clinical diagnosis of OHT (n = 25) or early to moderate OAG (n = 16) and 16 age-matched normal controls was examined. Retinal thickness was measured by Retinal Thickness Analyzer (RTA), acquiring 5 pre-defined scans covering the central 20 degrees of the fundus. RTA average thickness and thickness profile data, including hemispheric asymmetries calculated as relative (superior/inferior and nasal/temporal) or absolute (vertical and horizontal, ie, independent of which hemisphere was thinner) parameters, were calculated. For each eye, white-on-white Humphrey 30-2 visual field results were analyzed, in addition to standard global indices, by quantifying perimetric sensitivities for regions of the posterior pole corresponding to those sampled by the RTA.


RESULTS
On average, central retinal thickness was reduced (P < 0.05) in OAG compared with OHT or normal control eyes. Vertical hemispheric absolute thickness asymmetry was increased (P < or = 0.01) in OAG eyes compared with the other groups. Horizontal hemispheric absolute thickness asymmetry was increased (P < 0.01) in both OHT and OAG eyes, compared with control eyes. At least one of the RTA parameters was altered in 13 of 25 OHT (52%) and 12 of 16 OAG eyes (75%), most frequently involving thickness asymmetries. In OAG, but not OHT eyes, superior/inferior asymmetry was positively (r = 0.69, P < 0.01) correlated with the corresponding asymmetry in perimetric sensitivity.


CONCLUSIONS
The RTA can reveal increased hemispheric thickness asymmetries in both OHT and OAG eyes. In OAG eyes thickness asymmetries are associated with corresponding perimetric asymmetries. The findings in OHT eyes suggest that localized anatomic and functional damage to inner retina may not develop in parallel early in the disease process.
Salgarello
Tommaso
T
Institute of Ophthalmology, Catholic University, Rome, Italy. tomlabeye@rm.unicatt.it
Colotto
Alberto
A
Valente
Paola
P
Petrocelli
Gianni
G
Galan
Maria Elena
ME
Scullica
Luigi
L
Falsini
Benedetto
B
D000328:Adult; D000368:Aged; D000886:Anthropometry; D005260:Female; D005902:Glaucoma, Open-Angle / Q000175:diagnosis*; D006801:Humans; D007834:Lasers; D008297:Male; D008875:Middle Aged; D009798:Ocular Hypertension / Q000175:diagnosis; D012160:Retina / Q000473:pathology*; D012165:Retinal Ganglion Cells / Q000473:pathology; D058609:Visual Field Tests; D014794:Visual Fields