Aplicação de fórmula corretiva nas alterações da pressão intraocular dos pacientes submetidos a LASIK

Cabral, Thiago; Polido, Júlia; Pinheiro, Maurício Vieira; Silva, André Luís de Freitas; Goldbach, L.J.; Mascaro, Vera Lúcia Degaspare Monte; Serracarbassa, Pedro Durães; Araújo, Maria Emília Xavier dos Santos

doi:10.1590/s0004-27492011000200006

Cited by 5 publications

(4 citation statements)

References 9 publications

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“…This is consistent with a study performed by Silva et al in 2011, which found a weak correlation between average simulated keratometry and change in IOP readings. 21 Our result is also consistent with a study by Yin Lin et al that explored the factors that may alter IOP measurements following LASIK. These authors reported that CCT and central ablation depth are the main parameters to be considered.…”

Section: Discussionsupporting

confidence: 92%

<p>Intraocular Pressure Calculation in Myopic Patients After Laser-Assisted In Situ Keratomileusis</p>

Helmy¹,

Hashem²

2020

OPTH

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Background: Corneal refractive surgery is widely used worldwide. Myopia is the most common reason for laser-assisted corneal refractive surgery (LASIK) and one of the risk factors for glaucoma. Intraocular pressure (IOP) measurement becomes variable postoperatively as the results are affected by the decrease in corneal thickness and biomechanics. This prospective clinical case study attempted to establish a simple correction formula for the calculation of IOP in post-LASIK myopic patients. Methods: This study included 300 eyes of 150 patients with myopia and myopic astigmatism as a refractive error who underwent LASIK. IOP was measured preoperatively and 6 months postoperatively. Preoperative and postoperative corneal thickness as well as ablation depth were measured. Statistical analysis was performed to detect the relationship between ablation depth and change in IOP. An attempt was made to construct a correction formula for the calculation of post-LASIK IOP. Results: The age of the patients ranged between 18 and 50 (mean ± SD 34.78±8.8) years. The spherical equivalent of refractive error ranged between −1.5 and −10 diopters. The mean IOP decreased significantly from 15.72±2.37 mmHg preoperatively to 11.71±2.24 mmHg postoperatively, with a mean difference of 4±1.75 mmHg (p˂0.001). A positive correlation was detected between corneal thickness and IOP difference among patients both preoperatively and postoperatively (p˂0.001). A positive correlation was identified between ablation depth and IOP change (p˂0.001). The correction formula for IOP was established: Real IOP=4+0.7(preoperative IOP)−0.3(ablation depth). Conclusion: IOP measurements change after corneal refractive surgery with LASIK. A corrected formula may be a good option for the proper calculation of post-LASIK IOP.

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Section: Discussionsupporting

confidence: 92%

<p>Intraocular Pressure Calculation in Myopic Patients After Laser-Assisted In Situ Keratomileusis</p>

Helmy¹,

Hashem²

2020

OPTH

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“…Previously, large quantities of formulas have been raised to correct IOP values following corneal refractive surgeries [9–11]. However, various confounding factors including surgical designs (i.e., flap thickness, residual stromal bed thickness, optic zone diameter and ablation depth), individual differences (i.e., age, gender, race, refractions, corneal curvature corneal hydration and post-operative wound healing response) [12] and long-term postoperative topical steroid usage make these formulas widely divergent.…”

Section: Introductionmentioning

confidence: 99%

Changes in intraocular pressure values measured with noncontact tonometer (NCT), ocular response analyzer (ORA) and corvis scheimpflug technology tonometer (CST) in the early phase after small incision lenticule extraction (SMILE)

Shen

Su²,

Liu³

et al. 2016

BMC Ophthalmol

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BackgroundCorneal biomechanical properties are always compromised after corneal refractive surgeries thus leading to underestimated intraocular pressure (IOP) that complicates the management of IOP. We investigated the changes in postoperative baseline of IOP values measured with noncontact tonometer (NCT), ocular response analyzer (ORA) and corvis scheimpflug technology (CST) in the early phase after small incision lenticule extraction (SMILE).MethodsTwenty-two eyes (−6.76 ± 1.39D) of 22 moderate and high myopes, (28.36 ± 7.14 years, 12 male and 10 female) were involved in this prospective study. IOP values were measured using a non-contact tomometer (NCT-IOP), an ocular response analyzer (corneal-compensated IOP, IOPcc and Goldmann-correlated IOP, IOPg) and a Corvis scheimpflug technology tonometer (CST-IOP) preoperatively, at 20 min and 24 h, postoperatively. Repeated measures analysis of variance (RM-ANOVA), Pearson’s correlation analysis and multiple linear regression models (stepwise) were performed. Cut-off P values were 0.05.ResultsExcept for IOPcc, NCT-IOP, IOPg, and CST-IOP values significantly decreased after SMILE procedure (All P values <0.05). ΔCCT, as well as ΔMRSE and ΔKm, did not significantly correlated with ΔNCT-IOP, ΔIOPcc, ΔIOPg or ΔCST-IOP, (all P values >0.05). Multiple linear regression models (stepwise) showed that the practical post-operative IOP value was the main predictor of the theoretical post-operative NCT-IOP, IOPcc and IOPg values (all P values <0.001). The postoperative applanation time 1 (AT1) value (B = 8.079, t = 4.866, P < 0.001), preoperative central corneal thickness (CCT) value (B = 0.035, t = 2.732, P = 0.014) and postoperative peak distance (PD) value (B = 0.515, t = 2.176, P = 0.043) were the main predictors of the theoretical post-operative CST-IOP value.ConclusionsIOP values are underestimated when assessed after SMILE by using NCT-IOP, IOPg and CST-IOP. The practical postoperative IOPcc value and theoretical post-operative CST-IOP value may be more preferable for IOP assessment in the early phase after SMILE.Trial registrationCurrent Controlled Trials ChiCTRONRC13003114. Retrospectively registered 17 March 2013

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“…This is a critical factor in ablative corneal refractive surgery, which, along with other biomechanical changes induced by the procedure, affects the measurement of the IOP after the procedure. The underestimation of IOP after photorefractive surgery using Goldmann applanation tonometry, has been documented in many studies [17,[18][19][20]23,24,[27][28][29]31,32,[35][36][37][38].…”

Section: Patients With History Of Corneal Refractive Surgery With Exc...mentioning

confidence: 98%

“…Secondarily, it alters the precision of the IOP measurement, especially with applanation tonometers. Goldman tonometry has been widely shown to underestimate IOP after corneal photorefractive surgery [17,19,[20][21][22][23][24][25][26][27][28][29][30][31][32][33][34][35][36][37][38]. This underestimation of IOP may at some point delay the diagnosis of de novo glaucoma in patients with a history of refractive surgery [39][40][41][42][43][44].…”

Section: Introductionmentioning

confidence: 99%

Photorefractive surgery with excimer laser and its impact on the diagnosis and follow-up of glaucoma. A review

Arango¹,

Tello²,

Parra³

et al. 2021

CSO

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Excimer laser refractive surgery is a procedure performed worldwide to solve refractive errors and reduce dependence on glasses or contact lenses. There has been an increase in the number of procedures performed around the world. Myopia is the most common indication for corneal photorefractive surgery. Myopic patients have a higher risk of developing some type of glaucoma in their lifetime, such as primary open-angle glaucoma and others. Refractive surgery ablates central corneal stromal tissue, altering its thickness and biomechanics, which in turn makes it difficult to accurately measure intraocular pressure (IOP), since it underestimates it. This underestimation of IOP may delay the diagnosis of de novo glaucoma in patients with a history of refractive surgery. Each patient who wishes to undergo corneal refractive surgery should undergo a thorough glaucoma examination in order to monitor and detect the possible development and / or progression of glaucoma. A very useful practical approach is to perform a series of IOP measurements before and after surgery, when the eye is already stable, and the difference between the averages of the two sets of readings can then be used as a personalised correction factor for postoperative IOP monitoring in that eye. Also, if there is any suspicion of a possible glaucoma, paraclinical tests, such as coherent optical tomography of the retinal nerve fibre layer (RNFL), visual fields and photos of the optic nerve should be requested. All this data prior to refractive surgery should be provided to these patients, so that they can save it and give it to their treating ophthalmologists in the future.

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Aplicação de fórmula corretiva nas alterações da pressão intraocular dos pacientes submetidos a LASIK

Cited by 5 publications

References 9 publications

<p>Intraocular Pressure Calculation in Myopic Patients After Laser-Assisted In Situ Keratomileusis</p>

<p>Intraocular Pressure Calculation in Myopic Patients After Laser-Assisted In Situ Keratomileusis</p>

Changes in intraocular pressure values measured with noncontact tonometer (NCT), ocular response analyzer (ORA) and corvis scheimpflug technology tonometer (CST) in the early phase after small incision lenticule extraction (SMILE)

Photorefractive surgery with excimer laser and its impact on the diagnosis and follow-up of glaucoma. A review

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