Small-Aperture Strategies for the Correction of Presbyopia

H. Burkhard Dick

Disclosures

Curr Opin Ophthalmol. 2019;30(4):236-242. 

In This Article

Abstract and Introduction

Abstract

Purpose of review: The recent scientific literature provides evidence of long-term results with small-aperture corneal inlays, as well as new evidence from a multicenter postmarket study of small-aperture intraocular lenses (IOLs) and early reports of the use of topical agents for presbyopia correction through pupil constriction. The field of small-aperture optics is growing and changing rapidly.

Recent findings: This article reviews what is known to date about various small-aperture optics platforms, including a posterior chamber IOL, add on device, corneal inlay, contact lenses, and pupil-constricting drops. Additionally, the impact of small-aperture technologies on light perception and visual performance, as well as the relative merits of monocular versus binocular small apertures are discussed.

Summary: Small-aperture optics are a dynamic, physiologic solution to the problem of presbyopia. They are effective throughout the range of accommodation loss and in pseudophakia. Small-aperture optics offer an opportunity to improve vision in presbyopes with and without cataracts. In some forms, they may also be able to reduce the impact of aberrations or improve vision in eyes with corneal irregularities, scars, or iris damage.

Introduction

Humans have applied the concept of small-aperture optics for centuries, beginning with the early camera obscura and pinhole cameras, and continuing today with advanced surgical devices to improve vision in presbyopes with and without cataracts.

Channeling light through a small aperture -- whether artificial, induced, or natural -- blocks incident stray light and unfocused light from the periphery. This sharpens vision and extends the depth of field, or the distance from a visual target that remains in focus when looking at the target. A small aperture also minimizes the impact of corneal aberrations on vision. The relationship between higher order aberration (HOA) and pupil size is well known. With a smaller pupil, it is primarily paraxial light rays -- which are less susceptible to optical imperfections -- that reach the retina, while light rays from the more aberrated peripheral cornea are blocked. However, smaller pupils also transmit less total luminance to the retina, which might be expected to influence visual performance.

There are now corneal inlays, contact lenses, intraocular lenses (IOLs) and topical miotic drops that rely on the principles of small-aperture optics for presbyopia correction, either commercially available or in development. This article reviews each of these small-aperture platforms, including recently published outcomes. We will also address the latest information on the impact of small-aperture technologies on light perception and visual performance, as well as the relative merits of monocular versus binocular small apertures.

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