Adaptation to Progressive Additive Lenses: Potential Factors to Consider

Abstract

People develop presbyopia as part of the normal aging process. Most presbyopes adapt to progressive additive lens (PALs), while others do not. This investigation sought to determine whether the ability to modify disparity vergence or phoria was correlated to PALs adaptation. In experiment 1, a double-step paradigm quantified the ability to modify convergence responses in sixteen presbyopes. In experiment 2, thirty-one incipient presbyopes participated in a 5-minute sustained fixation task to evoke phoria adaptation where the magnitude and rate of phoria adaptation were measured. Then, the experiment was repeated after wearing PALs for one month. Linear regression analyses were conducted between the following parameters: near point of convergence, positive fusional vergence at near, vergence facility, net change in the magnitude of phoria adaptation, and the rate of phoria adaptation. The ability to change convergence average peak velocity was significantly greater (p < 0.03) in presbyopic PALs adapters compared to presbyopic PALs non-adapters. The rate of phoria adaptation and vergence facility were significantly greater (p < 0.03) in incipient presbyopic PALs adapters compared to incipient presbyopic PALs non-adapters. Vergence facility and the rate of phoria adaptation may have potential clinical utility in differentiating which patients may adapt to PALs and which ones will have more difficulty.

Reflexive Fusional Vergence and Its Plasticity Are Impaired in Convergence Insufficiency

“…The capacity to adaptively lengthen convergence responses has been associated with successful adaptation to progressive, multifocal lens wear in emerging presbyopes. 49 Intuitively, these two functions (vergence plasticity and successful spectacle adaptation) could be related, as multifocal lenses induce asymmetric geometric distortions of the retinal images. This altered sensory input requires rapid recalibrations of binocular alignment and other (oculo)motor control systems, such as the vestibular-ocular response gain, in order to maintain optimal performance and visual comfort.…”

“…If an individual is consistently exposed to such a stimulus, the amplitude and peak velocity of subsequent saccades or vergence are altered in order to compensate with an aim to minimizing the experimentally induced end-point error. A strong correlation between this form of plasticity in reflexive convergence responses and the successful use of multifocal spectacle lenses was recently reported, 49 suggesting that it plays a role in our ability to successfully adapt to changes in our visual environment.…”

Presbyopia: Effectiveness of correction strategies

“…As with so many presbyopia correction modalities, however, no spectacle lens is currently available capable of restoring the dynamic range of accommodation to the ageing eye. As a result, presbyopes continue to experience problems (Alvarez et al, 2017) particular in real-world environments (Konig et al, 2015), which can even result in secondary musculoskeletal symptoms (Weidling and Jaschinski, 2015) and falls (Elliott, 2014). Little research on progressive lens designs and their effectiveness in ameliorating presbyopia is published in the peer reviewed literature, with these mainly subjective trials of iterative design changes kept internal by the lens manufacturer.…”

Test–retest of a phoria adaptation stimulus-induced functional MRI experiment

“…To stimulate phoria adaptation for the functional MRI experiment, sustained fixation was utilized. This method of testing phoria adaptation has been shown to be an effective method ( Alvarez, Kim, & Granger-Donetti, 2017 ; Chen, Lee, Chen, Semmlow et al, 2010 ; Kim, Granger-Donetti, Vicci, & Alvarez, 2010 ; Kim, Vicci, Granger-Donetti, & Alvarez, 2011 ; Kim, Vicci, Han, & Alvarez, 2011 ; Lee et al, 2009 ) and does not require any physically moving parts. The overall timing sequence is shown in Figure 1 B.…”