Recommendations for intraocular pressure measurement one hour after laser peripheral iridotomy: Review of the literature.

PURPOSE: To determine the need to measure intraocular pressure one hour after laser peripheral iridotomy in patients with narrow angles, to determine the significance of the immediate IOP spike after LPI, and to assess risk factors associated with these. METHODS: A review of the literature on IOP measurements after LPI was conducted using the PubMed databases in January 2020. RESULTS: The proportion of treated eyes with an IOP spike one hour after treatment was between 6 and 9.8% depending on the study. Fewer than 1% of the eyes had an immediate post-treatment IOP of 30mmHg or more. Risk factors associated with IOP spikes include hyphema, pigment dispersion, and high pretreatment IOP. Patients of Asian descent, who possess thick irides, or any patient having thick irides, also exhibited increased risk of IOP spikes. CONCLUSIONS: The majority of the studies that have evaluated this complication were conducted in an Asian population, which affects the generalisability of these results to a wider population, considering anatomical differences. Although it is not uncommon to observe IOP spikes following LPI, the majority will not experience an increase of 10mmHg from baseline or a post-LPI IOP of 30mmHg or more. Even though it has been recommended to measure the IOP of all patients one hour after an LPI in order to avoid missing a spike, we suggest measuring IOP one hour after an LPI in patients who possess at least one risk factor or if there is any preexisting damage to the optic nerve.

Effects of Nd-YAG Laser iridotomy on anterior segment measurements in pigment dispersion syndrome and ocular hypertension.

PURPOSE: To compare the anterior segment optical coherence tomography (AS-OCT) measurements of eyes with pigment dispersion syndrome (PDS) and ocular hypertension (OHT) before and after neodymium:yttrium-aluminum-garnet (Nd:YAG) laser peripheral iridotomy (LPI). METHODS: A total of 23 eyes of 23 patients with PDS and OHT with features of PDS were included in this retrospective study. All of the eyes with PDS and OHT were examined by AS-OCT before and after Nd:YAG LPI. Anterior chamber depth, angle opening distance 500, angle opening distance 750, trabecular iris space 500, trabecular iris space 750 and scleral spur angle, iris bowing and iris shape were measured with AS-OCT by the same examiner. RESULTS: The differences in all parameters before and after Nd:YAG LPI were statistically significant. Iris configuration was concave in all eyes prior to iridotomy. After Nd:YAG laser iridotomy, the iris configuration became convex in 7 eyes, flat in 9 eyes and remained concave in 7 eyes. CONCLUSION: Nd:YAG laser peripheral iridotomy is an effective method for reversing the iris concavity and iris bowing in pigment dispersion syndrome.