Anita Manassakorn

Normative database of retinal nerve fiber layer and macular retinal thickness in a Thai population

PurposeTo investigate the distribution of retinal nerve fiber layer (RNFL) and macular retinal thickness measured by optical coherence tomography (OCT) in a Thai population.MethodsWe studied one eye each of 250 healthy subjects [age ≥ 18 years; spherical refractive error within ±6 diopters (D); astigmatism ≤3 D; no ocular pathology]. A complete eye examination, standard automated perimetry, and fast RNFL and macular thickness measurement by OCT were performed, and a disc photograph was taken. The distributions of both thicknesses, including their relationship with demographic data, were analyzed.ResultsThe mean ± SD age of the study population was 44.7 ± 12.2 years. The mean ± SD RNFL thickness was 109.3 ± 10.5 m, which was 10% thicker than that in the OCT normative database. RNFL decreased 2.3 m per decade (P < 0.001). Sex and spherical equivalent were not associated with RNFL thinning. The mean ± SD central foveal thickness was 183.2 ± 1.3 m. The macular thickness in the outer area was significantly thinner than that in the inner area (P < 0.001). The temporal regions were the thinnest among the four quadrants (P < 0.001). Thinning of all macular areas, except the center, was found to be associated with advancing age (P < 0.05).ConclusionsRNFL thickness in the measured Thai population was about 10% thicker than that in the original normative database. Macular thickness and RNFL thickness in the superior and inferior quadrants decreased with advancing age.

Retinal nerve fiber layer defect patterns in primary angle-closure and open-angle glaucoma: A comparison using optical coherence tomography

PurposeTo compare the patterns of retinal nerve fiber layer (RNFL) thickness loss in primary angle-closure glaucoma (PACG) and primary open-angle glaucoma (POAG) using optical coherence tomography (OCT).MethodsForty-three participants with PACG and 60 with POAG underwent fast RNFL thickness measurement by OCT. Eyes were classified according to the visual field mean deviation (VF-MD) into mild (>−8 dB), moderate (−8 dB to >−16 dB), and advanced (≤−16 dB) glaucoma subgroups. The raw RNFL thickness data were compared with data from the Thai normative database.ResultsMean (SD) age was 67.0 (9.6) and 64.1 (11.6) years in the PACG and POAG groups, respectively (P = 0.19). In the mild subgroups, a focal RNFL thickness loss was found in the inferior area in the POAG group, but not in the PACG group. The RNFL defect involved sectors 1, 6, and 7 in the moderately advanced disease subgroups of both PACG and POAG and extended through almost all sectors in the advanced disease subgroups. The deepest RNFL defect, −17.25 μm, was found in sector 6 of the mild POAG subgroup, compared with −8.78 μm in the PACG group (P = 0.04). The number of affected points in each sector in the mild subgroups was greater in the POAG group than in the PACG group.ConclusionParticipants with mild POAG had deeper and more localized RNFL defects than did participants with PACG. The pattern was similar in participants with moderate or advanced disease.