Ark 510a

Distance visual acuity (VA) was measured using a logarithm of the minimum angle of resolution (LogMAR) chart (Nidek, Gamagori, Japan). In the case of uncorrected VA in either eye being > 0.1, best-corrected visual acuity (BCVA) was subsequently measured in a monocular fashion using a trial frame. Refractive status was measured both before and after cycloplegia using an auto-refractor (Nidek ARK-510A, Gamagori, Japan). Two cycles of 1% cyclopentolate (Cyclogyl, Alcon-Convreur, Rijksweg, Belgium) and 1% tropicamide (Santen, Osaka, Japan) were given ten minutes apart. An additional third cycle of cyclopentolate and tropicamide drops was administered thirty minutes after the last drop if either a pupillary light reflex was still present, or pupil size was less than 6.0 mm. Detailed ocular examinations for the anterior segment and the retina were conducted by an ophthalmologist using a slit-lamp (Haag-Streit, Koeniz, Switzerland) and binocular ophthalmoscope with a 20D lens (Volk, Houston, TX) respectively.

Ophthalmologic examinations included visual acuity at 4 m (EDTRS, Wehen Co., Ltd., Guangzhou, China). Data related to refraction, such as corneal curvature radius, were measured with an auto ref-keratometer (ARK- 510A, Nidek Co., Ltd., Tokyo, Japan). Astigmatism was defined as cylinder value<− 0.50 D. We used a portable hand-held slit-lamp to examine the anterior segment of the eye (KJ5S2, Suzhou Kangjie Medical Co., Ltd., Jiangsu, China).

Well-trained ophthalmologists performed eye examinations on our participants. A logarithm of the minimum angle of resolution E chart (Wehen Co., Ltd., Guangzhou, China) was used for visual acuity measurement at 4 m. An auto ref-keratometer (ARK-510A, Nidek Co., Ltd., Tokyo, Japan) was used to measure noncycloplegic refraction and corneal curvature radium. The anterior segment of the eye was examined with a portable hand-held slit-lamp (KJ5S2, Suzhou Kangjie Medical Co. Ltd., Jiangsu, China).

After adequate mydriasis using topical 0.5% tropicamide,Retinoscopy was employed using a computer optometry instrument (Japan, NIDEK, ARK-510 A) to determine SE.
At baseline and subsequent follow-up visits, corneal topography (E300 Topographer, Medmont) was conducted, with a minimum of three topographic maps obtained at each measurement session. The highest-quality map was subsequently selected for analysis. From these maps, corneal topographic characteristics, and pupil size, were derived.
The study used a noncontact biometer (IOL Master; Carl Zeiss Jena GmbH, Jena, Germany) to measure baseline and 1.5-year axial length data. Three measurements were obtained at each visit, and the mean average value of the three separate measurements of axial length was recorded.

All the participants aged ≥18 years presenting to the health examination center of the Fourth People's Hospital of Shenyang from March 1 to April 30, 2017 were invited to attend. Three trained nonmedical staff conducted the ocular examinations including assessment of presenting visual acuity (PVA) (uncorrected if the participant did not own spectacles and with distance spectacles if worn), noncontact pneumotonometry (CT−1P Computerized Tonometer, Topcon Ltd., Tokyo, Japan), noncycloplegic autorefraction (ARK-510A, Nidek Co., Ltd., Tokyo, Japan), and nonmydriatic fundus photography (Canon CX-1, Tokyo, Japan). Only staffs achieving accuracy over 95% in PVA tests during the training phase were qualified for further screening. Fundus photographs were evaluated independently by two glaucoma specialists (SDZ and YBL). For autorefraction, three consecutive readings of sphere, cylinder, and axis of each eye were taken and the mean spherical equivalent (SE) (spherical power + $\raisebox{1ex}{$1$}\!\left/ \!\raisebox{-1ex}{$2$}\right.$
^* cylinder power) was used for analysis. Participants with PVA <6/12, intraocular pressure (IOP) ≥24 mm Hg, obvious lens opacity, or abnormalities on fundus photography in either eye were referred to the ophthalmology outpatient clinics.