Effects of obesity on retrobulbar flow hemodynamics: color Doppler ultrasound evaluation / Efeitos da obesidade na hemodinâmica do fluxo retrobulbar: avaliação por ultrassom doppler colorido

ABSTRACT Purpose: To evaluate intraocular pressure (IOP) and extraocular orbital vessels with color Doppler ultrasound (CDU) and investigate the effects of obesity on retrobulbar blood flow. Methods: Fifty-nine patients were included in this prospective study. Patients were divided into two groups according to body mass index: Group 1 (31 obese patients) and Group 2 (28 non-obese patients). IOP was measured with a Goldmann applanation tonometer, and CDU was used to evaluate the retrobulbar vessels. Results: The mean IOP was 18 ± 6.68 mmHg in the obese group and 13.71 ± 1.60 mmHg in the control group (p<0.001). When the CDU values for the central retinal artery were compared between the groups, the pulsatility index was found to be significantly lower in the obese group than in the control group (p<0.001). When the CDU values for the ophthalmic artery (OA) were compared between the groups, the peak systolic velocity (p<0.001) and end-diastolic velocity (p=0.002) values were found to be significantly lower in the obese group than in the control group. Conclusions: Obese patients have a higher mean IOP and lower flow velocity than non-obese patients. Increased IOP together with decreased retrobulbar blood flow, particularly in obese individuals, may increase the risk of glaucoma development.

RESUMO Objetivo: Avaliar a pressão intraocular (PIO) e vasos orbitários extraoculares com ultrassom Doppler colorido (UDC) e investigar os efeitos da obesidade sobre o fluxo sanguíneo retrobulbar. Métodos: Cinquenta e nove pacientes foram incluídos neste estudo prospectivo. Os pacientes foram divididos em dois grupos de acordo com o índice de massa corpo ral (IMC): Grupo 1 (31 pacientes obesos) e Grupo 2 (28 não obesos). As pressões intraoculares (PIOs) foram medidas com tonômetro de aplanação de Goldmann e o UDC foi utilizada para a avaliação de vasos retrobulbar. Resultados: As PIOs foram 18 ± 6,68 mmHg nos pacientes obesos e 13,71 ± 1,60 mmHg nos grupos controle (p<00,001). Quando os valores da artéria central da retina (ACR) foram comparados entre os grupos controle e obeso. O índice pulsátil (PI) foi marcadamente menor no grupo obeso (p<00,001). Quando os valores da artéria oftálmica (AO) dos grupos obesos e de controle foram comparados. Os valores de Velocidade do pico sistólico (PSV) (p<00,001) e velocidade diastólica final (EDV) (p=00,002) foram significativamente mais baixos no grupo obeso. Conclusão: Pacientes obesos têm maior PIO do que os pacientes não obesos. Os pacientes obesos têm diminuição nas velocidades de fluxo da AO. O aumento da PIO. Juntamente com a diminuição do fluxo sanguíneo retrobulbar, especialmente em indivíduos obesos, pode aumentar o risco de desenvolvimento de glaucoma.

Hemi-central retinal artery occlusion in young adults.

Amongst the clinical presentations of retinal artery occlusion, hemi-central retinal artery occlusion (Hemi-CRAO) is rarely described. This case series of four adults aged between 22 and 36 years attempts to describe the clinical profile, etiology and management of Hemi-CRAO. Case 1 had an artificial mitral valve implant. Polycythemia and malignant hypertension were noted in Case 2. The third patient had Leiden mutation while the fourth patient had Eisenmenger’s syndrome. Clinical examination and fundus fluorescein angiography revealed a bifurcated central retinal artery at emergence from the optic nerve head, in all cases. Color Doppler examination of the central retinal artery confirmed branching of the artery behind the lamina cribrosa. It is hypothesized that bifurcation of central retinal artery behind the lamina cribrosa may predispose these hemi-trunks to develop an acute occlusion if associated with underlying risk factors. The prognosis depends upon arterial recanalisation and etiology of the thromboembolic event.