Clinical context

Visual acuity alone is insufficient when judging corneal disease or surgery. Topography and tomography, surface regularity, biomechanics, endothelial cell density, quality of vision and stability all matter. After refractive procedures, epithelial healing, dry eye, haze, ectasia and the need for enhancement should be assessed separately.

What was studied

Posterior-chamber phakic-IOL safety depends on chamber depth, angle, volume, crystalline-lens anatomy and implant design, not refraction alone. This retrospective private-hospital study asked whether hyperopic and myopic eyes have different iridocorneal angles at the same anterior chamber depth. Records from patients aged 21–55 years included 44 hyperopic and 72 myopic eyes. ACD, angle, anterior chamber volume, white-to-white and spherical equivalent were extracted. Groups were matched 1:1 by ACD and also evaluated with regression.

How the evidence was produced

A cohort study describes how outcomes are associated with an exposure or treatment in an observed clinical population. This design is useful for routine practice, uncommon events and longer follow-up, but it remains vulnerable to confounding by indication, baseline risk differences and missing data. An association should not automatically be interpreted as a causal effect.

Key result In paired analysis, iridocorneal angle did not differ significantly between refractive groups, P=.356; anterior chamber volume also did not differ, P=.446. In covariance analysis, refractive group was not a significant angle predictor after adjustment for ACD, P=.193. An angle of at least 35° was defined as sufficiently wide. The proportion meeting this threshold increased with ACD but did not differ between hyperopic and myopic eyes. Measurements were Scheimpflug-based. In this population, hyperopic refraction itself did not add a detectable angle-narrowing effect after accounting for chamber depth.

How to interpret the result

The result supports measuring anatomy directly rather than assuming every hyperopic eye has a narrower angle. It does not establish the safety of hyperopic phakic-IOL implantation. Current hyperopic lenses are thicker and lack a central hole, so contact, block, IOP and endothelial risks require separate assessment. Lack of statistical significance is not proof of equivalence; a modest but clinically relevant difference may have been missed. Eligibility must follow the complete criteria for the specific lens and the individual anterior segment.

Clinical applicability

The study may refine technique selection and informed discussion, but its conclusions depend on baseline corneal shape, stromal thickness, equipment, nomogram and surgeon experience. Applicability requires comparison of these factors and attention to variability, uncommon complications and follow-up duration rather than mean values alone.

Limitations

This was a small retrospective single-center anatomical study, not an implantation-outcome study. A Scheimpflug angle is a surrogate and does not replace gonioscopy, endothelial-cell density, vault or dynamic iris assessment. The abstract does not report the number of matched pairs or fellow-eye distribution. The 35° threshold was study-defined. Verify matching, image quality, pupil and lighting conditions, lens thickness, age, WTW, power, missing data, funding and conflicts.

What to verify in the source

Use the DOI below to verify complete methods, result tables, funding and conflicts of interest.