Correction methods for noncontact intraocular pressure measurement in patients with keratoconus and healthy individuals / Métodos de correção para medição sem contato da pressão intraocular em indivíduos normais e com ceratocone

ABSTRACT Purpose: The objective of this study was to investigate the usefulness of four different algorithms to correct noncontact intraocular pressure measurement errors in keratoconus patients and normal individuals. Methods: Noncorrected intraocular pressure and corrected intraocular pressures were measured in one eye of 34 patients with keratoconus and 34 age- and gender-matched healthy controls using Corvis Scheimpflug Technology. The correlation of noncorrected intraocular pressure and corrected intraocular pressures with age, axial length, corneal shape, thickness, and biomechanics was calculated. Corrected intraocular pressures were compared with noncorrected intraocular pressure using paired t test and Bland-Altman plots (95% limits of agreement). Results: The noncorrected intraocular pressure correlated with corneal thickness and biomechanical parameters in both groups (all p≤0.047), and front and back mean keratometry in the keratoconus group (r=-0.39, p=0.02, and r=0.39, p=0.02, respectively). After adjustment with different intraocular pressure correction algorithms, biomechanically corrected intraocular pressure showed a minimal correlation with corneal features and a nonsignificant difference with noncorrected intraocular pressure in the healthy group (-0.1 ± 1.1 mmHg, p=0.58; 95% limits of agreement: -2.3 to 2.1 mmHg). Conclusions: Measuring intraocular pressure using noncontact tonometry and its corrected forms with a corneal thickness-based simple linear formula in patients with keratoconus is associated with many errors. Using more complex formulas that take into consideration more corneal stiffness parameters in addition to corneal thickness, such as biomechanically corrected intraocular pressure formula, may be more reliable and beneficial in this group of patients.

RESUMO Objetivo: Investigar a utilidade de quatro algoritmos diferentes para corrigir erros de medição sem contato da pressão intraocular em pacientes saudáveis e com ceratocone. Métodos: A pressão intraocular não corrigida e as pressões intraoculares corrigidas foram medidas em um olho de 34 pacientes com ceratocone e 34 pacientes do grupo controle saudável pareados por idade e gênero usando a tecnologia Corvis Scheimpflug. Foi calculada a correlação da pressão intraocular não corrigida e das pressões intraoculares corrigidas com idade, comprimento axial e formato, espessura e biomecânica da córnea. As pressões intraoculares corrigidas foram comparadas com a pressão intraocular não corrigida usando o teste t pareado, e gráficos de Bland-Altman (limites de concordância de 95%). Resultados: A pressão intraocular não corrigida correlacionou-se com a espessura da córnea e com os parâmetros biomecânicos em ambos os grupos (todos p≤0,047) e a ceratometria média frontal e posterior no grupo com ceratocone (r=-0,39, p=0,02, r=0,39, p=0,02, respectivamente). Após o ajuste com diferentes algoritmos de correção da pressão intraocular, a pressão intraocular corrigida biomecanicamente revelou uma correlação mínima com as características da córnea e uma diferença não significativa com a pressão intraocular não corrigida no grupo saudável (-0,1 ± 1,1 mmHg, p=0,58; limites de concordância de 95%: -2,3 a 2,1 mmHg). Conclusões: A medição da pressão intraocular usando tonometria sem contato e suas formas corrigidas usando fórmulas lineares, simples, baseadas na espessura da córnea em pacientes com ceratocone estão associadas a muitos erros. O uso de fórmulas mais complexas que consideram mais parâmetros de rigidez da córnea além da espessura da córnea, como fórmula de pressão intraocular corrigida biomecanicamente, pode ser mais confiável e benéfico neste grupo de pacientes.

Mini vitrectomy as an alternative technique for intraocular pressure adjustment in non-drainage scleral buckling / La minivitrectomía como técnica alternativa para el ajuste de la presión intraocular en el cerclaje escleral sin drenaje

Purpose In non-drainage scleral buckling, anterior chamber paracentesis is usually carried out to decrease intraocular pressure. When the buckling is extensive however, this technique may be inefficient and time consuming. In this study, we tried to determine if a mini 25-gauge pars plana vitrectomy could be used as an efficient and safe alternative procedure to anterior chamber paracentesis for adjusting intraocular pressure during a non-drainage scleral buckling. Methods In this case series, 44 patients with rhegmatogenous retinal detachment (proliferative vitreoretinopathy stage < C) were included. In all cases, a mini 25-gauge pars plana vitrectomy was performed before buckle fixation and repeated if necessary. Complete retinal attachment was defined as the anatomical success. Results Forty-four eyes of 44 patients with mean age of 48.1 ± 18.2 years were included. Silicon buckle nº 276, sponge 505, and sponge 507 were utilized for 7, 34, and 3 eyes, respectively. Intravitreal injection of SF6 gas was performed for 54.5% of the eyes. Mean total time of the operation was 61 ± 16 min and the mean time for vitrectomy was 87 ± 31 s. Complete retinal attachment in 37 and incomplete attachment in 4 eyes were achieved after single operation that was a success rate of 93.2%. One had more than usual vitreous leak at the site of scleretomy and one developed a tiny vitreous hemorrhage at the sclerotomy site. Three sclerotomy sites needed suturing. Conclusion The anatomical outcome and the safety observed in this study were comparable to the current methods reported in the literature. Therefore, if anterior chamber paracentesis fails to adjust intraocular pressure during a non-drainage scleral buckling, performing a small gauge mini vitrectomy is safe and helpful.

Application of kingdon and hall models to review environmental sanitation and health promotion policy in Ethiopia: a professional perspective as a review

BACKGROUND: In the world, many countries, including Ethiopia, are framing policies to roll back the problem of the sanitation. For this, the Kingdon and Hall models are the two distinct models formed to articulate the policy agenda to the health problem. The Kingdon model includes problem, policy and politics streams whereas the Hall model includes legitimacy, feasibility and support of the health policies. Therefore, this review aims to integrate the two models with diseases prevention and health promotion policies of Ethiopia. METHODS: We used the existing frameworks of the models as a guiding principle. Then, we applied the frameworks of the two models as an important consideration to interlink policy agenda to a given health problem. We also described the existing scientific literature about the sanitation and health promotion. After thoroughly reviewing, possible policy inputs and country setups were included with a brief discussion by comparing different kinds of literatures. RESULTS: The two models are recognized as an opportunity to get an essential sanitation policy. The government settled and has closed links to the new innovation as an emerged discourse. Therefore, the two model streams came together for setting sanitation problem on the policy agenda. The technical feasibility, public acceptability and congruence with existing values were all judged to be favorable. CONCLUSION: The integration of policies within the policy frameworks has very important outputs in various countries. Therefore, the field specialists should figure out the problem of policy integration through policy evaluation researches