Comparative evaluation of oculometric variables in graves' ophthalmopathy

OBJECTIVES: To estimate oculometric parameters of Graves' ophthalmopathy in comparison to healthy eyes using digital photography and digital image analysis. INTRODUCTION: Graves' ophthalmopathy is the main cause of eye proptosis. Because these protrusions cause clinically perceived distortions in orbital architecture, digital photographs can be used to detect and quantify these changes. METHODS: We carried out a cross-sectional study comprising 12 healthy volunteers and 15 Graves' ophthalmopathy patients with the purpose of evaluating the use of simple, non-invasive digital photography to estimate oculometric parameters of Graves' ophthalmopathy and compare them with the parameters of unaffected eyes. Facial photographs of cases and controls were taken in a standardized manner. Oculometric parameters were compared between the groups and then correlated to proptometer measures. RESULTS: All estimated oculometric variables showed significant differences between the groups, in particular with regard to mediopupilar aperture, lateral height, distance from the iris edge to the lateral boundary of the palpebral fissure, and distance from the higher point of the iris to the lateral limit of the palpebral fissure. The product of medial aperture and horizontal palpebral fissure also revealed greater discrepancy between the groups. Proptometer measures showed significant linear correlation between the distance from the iris edge to the lateral boundary of the palpebral fissure and between the distance from the higher point of the iris to the lateral limit of palpebral fissure (p<0.05). CONCLUSIONS: Comparative analysis of oculometric parameters in Graves' ophthalmopathy suggests that eye proptosis is related to an asymmetric increase in lateral oculometric measures. Standardized digital photographs can be used in clinical practice to objectively estimate oculometric parameters of Graves' ophthalmopathy patients.

Avaliação de parâmetros métricos oculares pela fotografia digital da face: uso do diâmetro da íris como unidade de referência / Evaluation of oculometric parameters by facial digital photography: use of iris diameter as a reference

OBJETIVO: Avaliar a precisão e reprodutibilidade de medidas oculares utilizando fotografia digital, além do emprego do diâmetro da íris dos pacientes como unidade de referência para essas estimativas. MÉTODOS: Fotografaram-se com câmera digital, de forma padronizada, 24 olhos em duas diferentes distâncias, e as imagens foram analisadas pelo software ImageJ 1.37v® e pela medida com paquímetro, por dois pesquisadores. Foram avaliados (em mm e em unidades de diâmetro de íris) diversos parâmetros oculares externos, com posterior comparação entre as unidades de referência, definindo-se precisão, concordância e correlação das medidas. RESULTADOS: Os parâmetros oculométricos estimados pela medida com paquímetro e pela análise de fotografia digital apresentaram significativas concordância e correlação, sendo maior a precisão das estimativas da análise digital. A conversão das medidas em unidades de diâmetro de íris apresentou alta correlação com as medidas em milímetros e alta concordância quando fotografadas a diferentes distâncias. CONCLUSÕES: A fotografia digital permitiu estimar com precisão e reprodutibilidade medidas oculares, confirmando sua utilidade na pesquisa clínica. O uso do diâmetro de íris como unidade de referência individual mostrou alta reprodutibilidade na avaliação de parâmetros métricos oculares em fotografias realizadas com diferentes distâncias.

PURPOSE: To evaluate reproducibility and precision of ocular measurements by digital photograph analysis, in addition to the transformation of the measures according to the individual iris diameter as an oculometric reference. METHODS: Twenty-four eyes have been digitally photographed in a standardized way at two distances. Two researchers have analyzed these printed images using a caliper and these digital forms by ImageJ 1.37™. Several external ocular parameters were estimated (mm and as iris diameter) and methods of measurement compared regarding their precision, agreement and correlation. RESULTS: Caliper and digital analysis of oculometric measures provided significant agreement and correlation, nevertheless the precision of digital measures was higher. The estimates of numeric transformation from oculometric measures according to individual iris diameter resulted in great correlation to caliper measures and high agreement when compared to different distances of taking the photographs. CONCLUSIONS: Facial digital photographs allowed oculometric precise and reproducible estimates, endorsing clinical research usefulness. Using iris diameter as individual oculometric reference disclosed high reproducibility when facial photographs were taken at different distances.