Dear Editor,
We read with great interest the article by Karimian et al comparing the effects of loteprednol with fluorometholone after myopic photorefractive keratectomy (PRK).[1]
We would like to congratulate the authors for their interesting and well-written paper, but we have some concerns regarding the criteria they used to establish the presence of increase in intraocular pressure (IOP).
It is well known that PRK changes several ocular parameters,[2,3] making certain measurements unreliable.[4] Among these, Goldmann applanation tonometry measurements become unreliable due to corneal thinning and flattening, resulting in underestimation of IOP.[5]
The authors defined steroid-induced ocular hypertension as IOP higher than 21 mmHg or a 10-mmHg rise in IOP compared with baseline. In our opinion, these criteria may underestimate the true increase in IOP. According to the literature, after PRK, there should be a decrease in the IOP measurements due to corneal thinning and flattening. For this reason, if we consider only patients with an increase in IOP >10 mmHg or measurements higher than 21 mmHg, some patients may be missed.
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Conflicts of Interest
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REFERENCES
- 1.Karimian F, Faramarzi A, Fekri S, Mohammad-Rabie H, Najdi D, Doozandeh A, et al. Comparison of loteprednol with fluorometholone after myopic photorefractive keratectomy. J Ophthalmic Vis Res. 2017;12:11–16. doi: 10.4103/2008-322X.200161. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 2.Rosa N, Capasso L, Lanza M, Romano A. Axial eye length evaluation before and after myopic photorefractive keratectomy. J Refract Surg. 2005;21:281–287. doi: 10.3928/1081-597X-20050501-12. [DOI] [PubMed] [Google Scholar]
- 3.Rosa N, Capasso L, Lanza M, Borrelli M. Clinical results of a corneal radius correcting factor in calculating intraocular lens power after corneal refractive surgery. J Refract Surg. 2009;25:599–603. doi: 10.3928/1081597X-20090610-05. [DOI] [PubMed] [Google Scholar]
- 4.Rosa N, De Bernardo M, Borrelli M, Lanza M. New factor to improve reliability of the clinical history method for intraocular lens power calculation after refractive surgery. J Cataract Refract Surg. 2010;36:2123–2128. doi: 10.1016/j.jcrs.2010.07.017. [DOI] [PubMed] [Google Scholar]
- 5.De Bernardo M, Capasso L, Caliendo L, Vosa Y, Rosa N. Intraocular pressure evaluation after myopic refractive surgery: A comparison of methods in 121 eyes. Semin Ophthalmol. 2016;31:233–242. doi: 10.3109/08820538.2014.962156. [DOI] [PubMed] [Google Scholar]