{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,8,17]],"date-time":"2026-08-17T11:26:45Z","timestamp":1786966005503,"version":"build-2736575974"},"reference-count":27,"publisher":"MDPI AG","issue":"8","license":[{"start":{"date-parts":[[2026,8,17]],"date-time":"2026-08-17T00:00:00Z","timestamp":1786924800000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Medicina"],"abstract":"<jats:p>Background and Objectives: Contact gonioscopy and optical biometry often happen at the same preoperative visit, with no defined interval between them. We asked whether uncomplicated Goldmann three-mirror gonioscopy was followed by short-term changes in optical biometry and calculated intraocular lens (IOL) power and whether any mean change could be positively affirmed as small enough not to matter clinically. Materials and Methods: Sixty-four cataract patients (128 eyes) underwent NIDEK AL-Scan biometry at baseline and 5, 15 and 30 min after unilateral Goldmann three-mirror gonioscopy in this prospective repeated-measures study (2015\u20132016). The untreated fellow eye served as an internal control. Our primary analysis was a within-patient paired difference-in-differences (DiD) comparison, which modeled the paired-eye structure directly; nested patient\/eye mixed-effects models followed as a sensitivity analysis. We recomputed IOL power as a continuous variable for four formulas, SRK\/T, Haigis, Hoffer Q and Holladay 1, using the published constants for the implanted lens. Equivalence within \u00b10.25 D was tested by two one-sided tests (TOSTs), with Holm adjustment across the twelve tests performed. Results: Central corneal thickness (CCT) rose by 3.14 \u00b5m at 5 min (95% CI, 1.94 to 4.35; p &lt; 0.001) and by 1.66 \u00b5m at 15 min (p = 0.015), returning to baseline by 30 min. That signal sat inside the \u00b16.2 \u00b5m short-term repeatability seen in untreated control eyes. Keratometry moved by no more than 0.11 D, and all four IOL formulas behaved almost identically, the largest mean difference being \u22120.18 D at 15 min. Equivalence within \u00b10.25 D was confirmed in unadjusted testing at 5 and 30 min for all four formulas and at 15 min for SRK\/T; after Holm adjustment only the four 30 min conclusions and the 5 min conclusion for SRK\/T were retained. The selected 0.5 D lens power changed in 33\u201347% of study eyes and in a comparable 31\u201352% of untreated control eyes. Conclusions: Procedure-related differences in calculated IOL power were small throughout. The largest was \u22120.18 D, inside the \u00b10.25 D margin and well below the 0.5 D interval on which lenses are supplied. Demonstrated equivalence was a narrower claim. After adjustment for multiplicity, it held at 30 min for all four formulas and at 5 min for SRK\/T, and at 15 min it was not demonstrated for Haigis, Hoffer Q or Holladay 1. These data therefore do not establish that biometry is unaffected across the whole first half hour, and we make no recommendation about deferring it. The transient CCT signal fell within device repeatability. Step-level changes in selected lens power were as common in eyes that never underwent gonioscopy. All analyses were exploratory and limited to a partial-coherence-class biometer of the study period and to the four formulas tested.<\/jats:p>","DOI":"10.3390\/medicina62081576","type":"journal-article","created":{"date-parts":[[2026,8,17]],"date-time":"2026-08-17T10:04:36Z","timestamp":1786961076000},"page":"1576","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":0,"title":["Transient Corneal Response After Goldmann Three-Mirror Gonioscopy and Its Limited Effect on Optical Biometry and Calculated Intraocular Lens Power: A Prospective Within-Subject Controlled Observational Study"],"prefix":"10.3390","volume":"62","author":[{"ORCID":"https:\/\/orcid.org\/0000-0002-7869-524X","authenticated-orcid":false,"given":"Ahmet Taner","family":"Uysal","sequence":"first","affiliation":[{"name":"Department of Ophthalmology, Trabzon Kanuni Training and Research Hospital, 61290 Trabzon, T\u00fcrkiye"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0009-0008-0304-5278","authenticated-orcid":false,"given":"Ahmet Mehmet","family":"Somuncu","sequence":"additional","affiliation":[{"name":"Department of Ophthalmology, Trabzon Kanuni Training and Research Hospital, 61290 Trabzon, T\u00fcrkiye"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Adem","family":"T\u00fcrk","sequence":"additional","affiliation":[{"name":"Department of Ophthalmology, Faculty of Medicine, Karadeniz Technical University, 61080 Trabzon, T\u00fcrkiye"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"1968","published-online":{"date-parts":[[2026,8,17]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"P1","DOI":"10.1016\/j.ophtha.2021.10.006","article-title":"Cataract in the Adult Eye Preferred Practice Pattern","volume":"129","author":"Miller","year":"2022","journal-title":"Ophthalmology"},{"key":"ref_2","doi-asserted-by":"crossref","first-page":"e94","DOI":"10.1016\/j.ophtha.2020.08.010","article-title":"Intraocular lens power formulas, biometry, and intraoperative aberrometry: A review","volume":"128","author":"Kane","year":"2021","journal-title":"Ophthalmology"},{"key":"ref_3","doi-asserted-by":"crossref","first-page":"368","DOI":"10.1016\/j.jcrs.2007.10.031","article-title":"Sources of error in intraocular lens power calculation","volume":"34","author":"Norrby","year":"2008","journal-title":"J. Cataract. Refract. Surg."},{"key":"ref_4","doi-asserted-by":"crossref","first-page":"e115","DOI":"10.1016\/j.ophtha.2020.07.005","article-title":"Update on intraocular lens power calculation study protocols: The better way to design and report clinical trials","volume":"128","author":"Hoffer","year":"2021","journal-title":"Ophthalmology"},{"key":"ref_5","doi-asserted-by":"crossref","first-page":"17","DOI":"10.1016\/S0886-3350(88)80059-2","article-title":"A three-part system for refining intraocular lens power calculations","volume":"14","author":"Holladay","year":"1988","journal-title":"J. Cataract. Refract. Surg."},{"key":"ref_6","doi-asserted-by":"crossref","first-page":"472","DOI":"10.1111\/j.1755-3768.2007.00879.x","article-title":"Calculation of intraocular lens power: A review","volume":"85","author":"Olsen","year":"2007","journal-title":"Acta Ophthalmol. Scand."},{"key":"ref_7","doi-asserted-by":"crossref","first-page":"861","DOI":"10.1016\/S0886-3350(00)00699-4","article-title":"Improved prediction of intraocular lens power using partial coherence interferometry","volume":"27","author":"Findl","year":"2001","journal-title":"J. Cataract. Refract. Surg."},{"key":"ref_8","doi-asserted-by":"crossref","first-page":"524","DOI":"10.1016\/S0002-9394(98)00113-5","article-title":"Partial coherence interferometry: A novel approach to biometry in cataract surgery","volume":"126","author":"Drexler","year":"1998","journal-title":"Am. J. Ophthalmol."},{"key":"ref_9","doi-asserted-by":"crossref","first-page":"709","DOI":"10.1016\/j.jcrs.2013.09.020","article-title":"Comparison of ocular biometry and intraocular lens power using a new biometer and a standard biometer","volume":"40","author":"Srivannaboon","year":"2014","journal-title":"J. Cataract. Refract. Surg."},{"key":"ref_10","doi-asserted-by":"crossref","first-page":"739652","DOI":"10.1155\/2014\/739652","article-title":"Evaluation of the repeatability and the reproducibility of AL-Scan measurements obtained by residents","volume":"2014","author":"Kola","year":"2014","journal-title":"J. Ophthalmol."},{"key":"ref_11","doi-asserted-by":"crossref","first-page":"1304","DOI":"10.1038\/s41598-018-19605-6","article-title":"Precision of a new ocular biometer in children and comparison with IOLMaster","volume":"8","author":"Yu","year":"2018","journal-title":"Sci. Rep."},{"key":"ref_12","doi-asserted-by":"crossref","first-page":"585","DOI":"10.1097\/j.jcrs.0000000000000494","article-title":"Repeatability of biometry measured by three devices and its impact on predicted intraocular lens power","volume":"47","author":"Shetty","year":"2021","journal-title":"J. Cataract. Refract. Surg."},{"key":"ref_13","doi-asserted-by":"crossref","first-page":"26762","DOI":"10.1038\/s41598-024-77572-7","article-title":"Short-term variability in ocular biometry and the impact of preoperative dry eye","volume":"14","author":"Ahn","year":"2024","journal-title":"Sci. Rep."},{"key":"ref_14","doi-asserted-by":"crossref","first-page":"55","DOI":"10.1016\/j.ajo.2011.06.012","article-title":"Repeatability and reproducibility of biometry and keratometry measurements using a noncontact optical low-coherence reflectometer and keratometer","volume":"153","author":"Shammas","year":"2012","journal-title":"Am. J. Ophthalmol."},{"key":"ref_15","doi-asserted-by":"crossref","first-page":"250","DOI":"10.1016\/j.survophthal.2007.10.012","article-title":"Anterior chamber angle assessment techniques","volume":"53","author":"Friedman","year":"2008","journal-title":"Surv. Ophthalmol."},{"key":"ref_16","first-page":"112","article-title":"Primary glaucomas: Gonioscopy, ophthalmoscopy and perimetry","volume":"64","author":"Shaffer","year":"1960","journal-title":"Trans. Am. Acad. Ophthalmol. Otolaryngol."},{"key":"ref_17","first-page":"709","article-title":"The normal development of the human anterior chamber angle: A new system of descriptive grading","volume":"91","author":"Spaeth","year":"1971","journal-title":"Trans. Ophthalmol. Soc. UK"},{"key":"ref_18","doi-asserted-by":"crossref","unstructured":"George, M.K., Kuriakose, T., DeBroff, B.M., and Emerson, J.W. (2006). The effect of gonioscopy on keratometry and corneal surface topography. BMC Ophthalmol., 6.","DOI":"10.1186\/1471-2415-6-26"},{"key":"ref_19","first-page":"2515841419892070","article-title":"Changes in preoperative corneal measurements following same-day intraocular pressure testing with rebound tonometry","volume":"12","author":"Beckman","year":"2020","journal-title":"Ther. Adv. Ophthalmol."},{"key":"ref_20","unstructured":"Uysal, A.T. (2019). Effect of Goldmann Three-Mirror Gonioscopy on Ocular Biometric Measurements and Intraocular Lens Power Calculation. [Residency Thesis, Karadeniz Technical University Faculty of Medicine]."},{"key":"ref_21","doi-asserted-by":"crossref","first-page":"333","DOI":"10.1016\/S0886-3350(13)80705-5","article-title":"Development of the SRK\/T intraocular lens implant power calculation formula","volume":"16","author":"Retzlaff","year":"1990","journal-title":"J. Cataract. Refract. Surg."},{"key":"ref_22","doi-asserted-by":"crossref","first-page":"7","DOI":"10.1016\/j.sjopt.2011.11.007","article-title":"Challenges and approaches in modern biometry and IOL calculation","volume":"26","author":"Haigis","year":"2012","journal-title":"Saudi J. Ophthalmol."},{"key":"ref_23","doi-asserted-by":"crossref","first-page":"700","DOI":"10.1016\/S0886-3350(13)80338-0","article-title":"The Hoffer Q formula: A comparison of theoretic and regression formulas","volume":"19","author":"Hoffer","year":"1993","journal-title":"J. Cataract. Refract. Surg."},{"key":"ref_24","doi-asserted-by":"crossref","first-page":"367","DOI":"10.1016\/S0039-6257(00)00110-7","article-title":"Human corneal thickness and its impact on intraocular pressure measures: A review and meta-analysis approach","volume":"44","author":"Doughty","year":"2000","journal-title":"Surv. Ophthalmol."},{"key":"ref_25","doi-asserted-by":"crossref","first-page":"34","DOI":"10.1111\/j.1755-3768.1975.tb01135.x","article-title":"Applanation tonometry and central corneal thickness","volume":"53","author":"Ehlers","year":"1975","journal-title":"Acta Ophthalmol."},{"key":"ref_26","doi-asserted-by":"crossref","first-page":"1779","DOI":"10.1016\/S0161-6420(01)00760-6","article-title":"Central corneal thickness in the Ocular Hypertension Treatment Study (OHTS)","volume":"108","author":"Brandt","year":"2001","journal-title":"Ophthalmology"},{"key":"ref_27","doi-asserted-by":"crossref","first-page":"1553","DOI":"10.21037\/atm-20-2290","article-title":"Recent developments in intraocular lens power calculation methods-update 2020","volume":"8","author":"Savini","year":"2020","journal-title":"Ann. Transl. Med."}],"container-title":["Medicina"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/www.mdpi.com\/1648-9144\/62\/8\/1576\/pdf","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2026,8,17]],"date-time":"2026-08-17T10:59:25Z","timestamp":1786964365000},"score":1,"resource":{"primary":{"URL":"https:\/\/www.mdpi.com\/1648-9144\/62\/8\/1576"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2026,8,17]]},"references-count":27,"journal-issue":{"issue":"8","published-online":{"date-parts":[[2026,8]]}},"alternative-id":["medicina62081576"],"URL":"https:\/\/doi.org\/10.3390\/medicina62081576","relation":{},"ISSN":["1648-9144"],"issn-type":[{"value":"1648-9144","type":"electronic"}],"subject":[],"published":{"date-parts":[[2026,8,17]]}}}