Presentation on theme: "The target IOP is the mean IOP obtained with treatment that prevents further glaucomatous damage in the eye of the individual under consideration. The."— Presentation transcript:
The target IOP is the mean IOP obtained with treatment that prevents further glaucomatous damage in the eye of the individual under consideration. The main problems of target IOP assessment are: it must be individualized to the patient and to each eye; it should be an accurate estimate it needs to be determined in advance. Estimation of the target IOP A) For any individual who has unquestionable damage as a result of glaucoma, but in the early stage (see Hodapp's grading system),“ a_20% decrease in IOP is advisable. For moderate and advance damage, a 30 and 40% decrease of IOP from baseline, respectively, is proposed. In addition to glaucoma damage stage, one can also consider recognized risk factors for further progression. B) The initial IOP is related to the cup disc changes as well as the field in four grades using a simple formula [(max. IOP - % reduction) – Z] and Z depends on the disc or field damage C)Traverso C E, proposed to add a further 3% IOP lowering for each risk factor or for each decade of life expectancy; no more than four factors are to be added, however. D) other methods described take in consideration the risk factors in detail It is useful, however, to think in terms of an algorithm to rationalize the need for individualized IOP goals in each eye of each patient. A better definition of true risk factors for progression and of life expectancy are mandatory for the application of this algorithm.( Traverso C E) What is new? We are providing in this study a proposal for estimation of the target IOP individualized for each eye, determined accurately in advance as demanded by Traverso. how ? The risk factors for getting glaucoma include age, race, sex, heredity, family history, systemic (Diabetes, Obesity, Hypertension, Hypotension, arteriosclerosis and smoking) and socioeconomic factors as well as local factors (myopia, corneal thickness and scleral rigidity) all will channel into the resultant level of IOP and disc damage. So calculation of the combined probability of getting glaucoma for these 2 factors alone will include all the above mentioned variables. Table Subjects and methods The cases introduced will scan most of our clinical need to estimate the target IOP Target IOP In cases in whom treatment is necessary we have to achieve the target IOP Our target IOP is to reduce the pressure to a probability of 0.10 or maximally 0.20 if it is possible taking in consideration that the IOP has to be corrected for any change in the corneal thickness or scleral rigidity. The target pressure in our study is related to the C/D ratio (corrected). (table 2) Management Normal:nothing to be done Possible :observe Probable: treat and observe Highly probable: treatment vigorously & observe Definite: full tolerable treatment, laser or surgery & observe ReferencesReferences : 1.. Carlo E Traverso. Identifying the target intraocular pressure and adjusting treatment In Robert N Weinreb, Yoshiaki Kitazawa, Günther K Krieglstein, ; Glaucoma in the 21 st Century ; Mosby International Ltd 2000 published by Harcourt Health communication 2.Collaborative Normal ‑ Tension Glaucoma Study Group. Comparison of glaucoma progression between untreated patients with normal tension glaucoma and patients with therapeutically reduced intraocular pressures. Am J Ophthalmol 1998;126:487 ‑ 497. 3.Collaborative Normal ‑ Tension Glaucoma Study Group. The effectiveness of intraocular pressure reduction in the treatment of normal ‑ tension glaucoma. Am j Ophthalmol 1998;126:498 ‑ 505. 4.Traverso CE, Semino E, Morescalchi S, et al. Is the visual field of patients with advanced POAG protected by lowering the IOP? In: Mills RP, Wall M, eds. Perimetry update 1994/1995. Amsterdam: Kugler; 1995:309 ‑ 312. 5. Devindra Sood, NN Sood ‘ primary open angle glaucoma, Modern Ophthalmology 3 rd Edition, Editor LC Dutta, publisher Jaypee. Vol 1 Ch 66 page 494 6. Saif SSEH, Saif MYS, Saif ATS. Early Detection of Glaucoma, A New Scoring System; Bull. Ophthalmol. Soc. Egypt,2005;vol 98,number 3, 351-358 7. Davanger M, Ringvold A, Bilka S. The probability of having glaucoma at different IOP levels. Acta Ophthalmol. 1991;69:565-8 8. Wensor MD, McCarty CA, Stanislavsky YL, Livingston PM, Taylor HR. The prevalence of glaucoma in the Melbourne Visual Impairment Project. Ophthalmology. 1998 Apr;105(4):733-9. Mao LK, Steward LC, Shields MB. Correlation between intraocular pressure control and progressive glaucomatous damage in primary open ‑ angle glaucoma. Am J Ophthalmol 1991;111:51 ‑ 55. Target Intraocular pressure What is new? Prof Dr Sayed S. E. H. Saif, MD ; Dr M. Yasser S Saif, MD ; Dr Ahmed T.S. Saif, MD Professor of Ophthalmology, Cairo University Lecturer of Ophthalmology, Beni Sweif University Lecturer of Ophthalmology, Fayoum University Figure 1 demonstrates the probability of getting glaucoma (Y1)in relation to the IOP(X) and its derived equationY1=Y0+A1eX/T1 Y1= the probability of the incidence of POAG in the next 5 years when the IOP = x1 ( modified from Davanger M, Ringvold A, Bilka S. The probability of having glaucoma at different IOP levels. Acta Ophthalmol. 1991;69:565-8)9 Figure 2 : demonstrates the probabilty of getting glaucoma (Y2) in relation to the C/D ratio (X)Y2=Y0+A1eX/T1 Y2= the probability of the incidence of POAG in the next 5 years when the C/D ratio = x2 8 (formulated from the results of Wensor MD, McCarty CA, Stanislavsky YL, Livingston PM, Taylor HR. The prevalence of glaucoma in the Melbourne Visual Impairment Project. Ophthalmology. 1998 Apr;105(4):733-9.)6 The combined probability will take in consideration the IOP (Y1) and the C/D (Y2) ratio as the resultant outcome as shown in table1. 8 Y1+Y2 2 Early diagnosis Accordingly people are classified after calculation of the probability of getting glaucoma into the following: Normal up to 0.10 on the probability scale with normal IOP up to 21 mmHg and C/D ratio up to 0.5: (Nothing to be done) Ocular hypertension in whom the rise of IOP above 21 mmHg is the only sign with normal C/D ratio and their management will follow the general scheme of possible, probable, or definite as will be demonstrated. Possible up to 0.20 on the probability scale with rise of IOP more than 21 mmHg and increase of C/D ratio but the combined probability will not exceed 0.20.(Observation) Probable up to 0.30 on the probability scale (these has to be treated and observed) a monotherapy may be sufficient to achieve the target IOP Highly probable up to 0.40 on the probability scale (treatment vigorously and observe) a bi-therapy may be needed to achieve the target IOP Definite more than 0.40 on the probability scale (full tolerable treatment, laser or surgery and observe to achieve the target IOP) Web Page: www.sayedsaif.com Email: email@example.com, firstname.lastname@example.org Tel: +20 10 66 99 288, + 20 12 34 56 email@example.com@gawab.com
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