University of Macau / Faculty of Health Sciences

The purpose of this thesis was to investigate the effect of corneal swelling on the accuracy of Goldmann tonometry estimates of intraocular pressure (IOP). In the first experiment, central corneal thickness (CCT, ultrasonic pachymetry), IOP (Goldmann tonometry) and corneal curvature (keratometry) was measured in one eye of 25 subjects every two hours for 24 hours, except for 8 hours overnight (no measurements taken), and for the first two hours after awakening (measurement frequency 20 minutes). CCT (+20.1??10.9 pm) and IOP (+3.1??2.4 mmHg) peaked on eye opening, and then decreased at a similar rate (r=0.967, p<0.001) for the next two hours. Corneal swelling may have influenced the accuracy of Goldmann IOP measurements during this time. In the second and third studies, the CCT, IOP and corneal curvature were measured in both eyes of two groups of 25 subjects before and after the induction of corneal swelling, resulting from two hours of monocular closed eye contact lens wear. The increase in IOP was correlated to the increase in CCT at a rate of 0.33 to 0.48 mmHg per 10 pm, which signified an overestimation error in Goldmann IOP measurement. However, the change in IOP could not be accounted for solely by the change in CCT. In the fourth study, CCT, IOP and corneal curvature were used in conjunction with the Orssengo-Pye algorithm to determine the range of Young's modulus in the normal population, which was 0.29??0.06 MPa. Physiological variations in Young's modulus had a similar effect on Goldmann tonometry to CCT. In the fifth study, the data collected for studies 2 and 3 was used to calculate the Young's modulus changes associated with corneal swelling, again with the assistance of the Orssengo-Pye algorithm. No systematic change in Young's modulus was recorded after contact lens wear, but the model suggested that corneal biomechanical changes were responsible for the remainder of the change in IOP. All experimental results were combined to develop a model to calculate the diurnal variation of Goldmann IOP errors. The likely error in IOP due to overnight corneal swelling was 0.6 to 1.4 mmHg, which may explain as much as 45% (1.4 mmHg) of the 3.1 mmHg diurnal variation of IOP. In summary, small amounts of corneal swelling were shown to have a clinically significant impact on the accuracy of Goldmann tonometry. This may interfere with the measurement of the diurnal variation of IOP, particularly if measurements are taken prior to the resolution of overnight corneal swelling.

The purpose of this thesis was to investigate the effect of corneal swelling on the accuracy of Goldmann tonometry estimates of intraocular pressure (IOP). In the first experiment, central corneal thickness (CCT, ultrasonic pachymetry), IOP (Goldmann tonometry) and corneal curvature (keratometry) was measured in one eye of 25 subjects every two hours for 24 hours, except for 8 hours overnight (no measurements taken), and for the first two hours after awakening (measurement frequency 20 minutes). CCT (+20.1??10.9 pm) and IOP (+3.1??2.4 mmHg) peaked on eye opening, and then decreased at a similar rate (r=0.967, p<0.001) for the next two hours. Corneal swelling may have influenced the accuracy of Goldmann IOP measurements during this time. In the second and third studies, the CCT, IOP and corneal curvature were measured in both eyes of two groups of 25 subjects before and after the induction of corneal swelling, resulting from two hours of monocular closed eye contact lens wear. The increase in IOP was correlated to the increase in CCT at a rate of 0.33 to 0.48 mmHg per 10 pm, which signified an overestimation error in Goldmann IOP measurement. However, the change in IOP could not be accounted for solely by the change in CCT. In the fourth study, CCT, IOP and corneal curvature were used in conjunction with the Orssengo-Pye algorithm to determine the range of Young's modulus in the normal population, which was 0.29??0.06 MPa. Physiological variations in Young's modulus had a similar effect on Goldmann tonometry to CCT. In the fifth study, the data collected for studies 2 and 3 was used to calculate the Young's modulus changes associated with corneal swelling, again with the assistance of the Orssengo-Pye algorithm. No systematic change in Young's modulus was recorded after contact lens wear, but the model suggested that corneal biomechanical changes were responsible for the remainder of the change in IOP. All experimental results were combined to develop a model to calculate the diurnal variation of Goldmann IOP errors. The likely error in IOP due to overnight corneal swelling was 0.6 to 1.4 mmHg, which may explain as much as 45% (1.4 mmHg) of the 3.1 mmHg diurnal variation of IOP. In summary, small amounts of corneal swelling were shown to have a clinically significant impact on the accuracy of Goldmann tonometry. This may interfere with the measurement of the diurnal variation of IOP, particularly if measurements are taken prior to the resolution of overnight corneal swelling.

Orientador: Newton Kara-Jose / Tese (doutorado) - Universidade Estadual de Campinas, Faculdade de Ciencias Medicas / Made available in DSpace on 2018-08-13T21:12:46Z (GMT). No. of bitstreams: 1 Costa_DacioCarvalho_D.pdf: 11382661 bytes, checksum: a5c3e2c591c002085753bfe5397e34f3 (MD5) Previous issue date: 2009 / Resumo: Objetivo: Comparar a eficácia da injeção subconjuntival de 20 mg de triancinolona associada a prednisolona 1% tópica com a injeção intravenosa de 500 mg de metilprednisolona associada a prednisolona 1% tópica no tratamento da rejeição endotelial de transplante de córnea. Métodos: Estudo caso-controle realizado no Hospital das Clínicas da UNICAMP. Os pacientes submetidos a transplante penetrante de córnea que apresentaram primeiro episódio de rejeição endotelial com até 15 dias do início dos sintomas durante o período de novembro de 2005 a outubro de 2006 foram tratados com injeção subconjuntival de 20 mg de acetonido de triancinolona associado a acetato de prednisolona 1% tópico. Estes pacientes foram pareados por idade e diagnóstico com pacientes submetidos a tratamento com injeção intravenosa de 500 mg de succinato sódico de metilprednisolona associado a acetato de prednisolona 1% tópico e analisados quanto à capacidade de reversão do episódio de rejeição, pressão intraocular aos 30 dias e acuidade visual ao final de 1 ano. Resultados: 16 pacientes foram tratados com 20 mg de triancinolona subconjuntival e prednisolona 1% tópica durante o período de recrutamento e foram pareados com 16 pacientes tratados com 500 mg de metilprednisolona intravenosa e prednisolona 1% tópica. Ao final de 1 ano, o grupo tratado com triancinolona obteve melhores resultados do que o grupo tratado com metilprednisolona (p=0,025), obtendo 15 pacientes com córnea transparente enquanto o grupo tratado com metilprednisolona obteve 10 pacientes. 3 pacientes do grupo tratado com triancinolona apresentaram segundo episódio de rejeição durante o seguimento e foram retratados com sucesso enquanto no grupo da metilprednisolona, 4 pacientes apresentaram segunda rejeição, com 2 pacientes apresentando falência com o retratamento e 2 obtendo sucesso. A pressão intraocular subiu nos dois grupos (p=0,002) após 30 dias, porém não houve diferença entre os grupos (p=0,433). A acuidade visual melhorou após 1 ano em ambos os grupos (p=0,049) e o grupo tratado com triancinolona obteve melhor acuidade visual (p=0,002). Conclusão: A injeção subconjuntival de 20 mg de triancinolona combinada com prednisolona 1% tópica mostrou-se mais eficaz em reverter episódios de rejeição de transplante de córnea neste estudo caso-controle do que a aplicação intravenosa de 500 mg de metilprednisolona. Estudos adicionais necessitam ser realizados para verificar a segurança e eficácia deste tratamento em grandes populações / Abstract: Purpose: To compare the efficacy of 20 mg subconjunctival triamcinolone in association with topical prednisolone 1% to 500 mg intravenous methylprednisolone in association with topical prednisolone 1% in the treatment of cornea endothelial graft rejection. Methods: Case-control study carried out at State University of Campinas Hospital. Patients submitted to penetrating keratoplasty that presented first episode of corneal endothelial rejection within 15 days of symptoms onset between November 2005 and October 2006 were treated with 20 mg subconjunctival injection of triamcinolone acetate in association with topical prednisolone acetate 1%. These patients were matched for age and diagnosis to patients that were submitted to a single 500 mg intravenous injection of methylprednisolone sodium succinate in association with topical prednisolone acetate 1% and analyzed regarding the reversion of the rejection episode, intraocular pressure at day 30 and visual acuity at the end of 1 year. Results: 16 patients were treated with 20 mg subconjunctival triamcinolone and topical prednisolone 1% during the period of recruitment and were matched to 16 patients treated with 500 mg intravenous methylprednisolone and topical prednisolone 1%. At the end of 1 year, the group treated with triamcinolone had a better outcome than the group treated with methylprednisolone (p=0.025), having 15 patients with clear grafts as the group treated with methylprednisolone had 10 patients. 3 patients from the group treated with triamcinolone had new rejection episodes during follow-up and were retreated successfully as in the group treated with methylprednisolone 4 patients had a new rejection episode, with 2 progressing to failure and 2 to success with retreatment. Intraocular pressure rose in both groups (p=0.002) at day 30 but there were no statistically significant differences between the groups (p=0.433). Visual acuity improved after 1 year in both groups (p=0.049) and the group treated with triamcinolone had better visual acuities (p=0.002). Conclusions: 20 mg subconjunctival injection of triamcinolone acetonide associated with topical prednisolone acetate 1% showed to be more effective than 500 mg intravenous methylprednisolone associated with prednisolone acetate 1% in this case-control study. Further studies need to be accomplished to verify its safety and effectiveness in larger populations / Doutorado / Oftalmologia / Doutor em Ciências Médicas