A topical product (PresbiDrops, FEPASAET Group) that provides sustained pupil constriction can safely and effectively increase near and distance UCVA in properly selected presbyopic patients.
Take-home message: A topical product (PresbiDrops, FEPASAET Group) that provides sustained pupil constriction can safely and effectively increase near and distance UCVA in properly selected presbyopic patients.
By Cheryl Guttman Krader; Reviewed by Claes Feinbaum, MSc, PhD
Beersheba, Israel-Topical treatment with an investigational proprietary product (PresbiDrops, FEPASAET Group) that combines a parasympathomimetic agent with an NSAID in an oil-based formulation safely and effectively improves near and distance uncorrected visual acuity in properly selected presbyopic patients with low distance prescriptions, according to a study conducted by Claes G. Feinbaum, MSc, PhD.
The efficacy of the pharmacological intervention is explained by changes in pupil size that affect clinical depth of field (DoF) and higher order aberrations (HOAs).
In a series of 81 patients who underwent testing before and 30 to 45 minutes after instillation of 1 or 2 drops of the topical medication, mean pupil size was reduced by an average of 1 mm and was associated with an average 0.9 D increase in DoF.
Both UNVA and UDVA were also significantly improved.
“Excimer laser ablation, femtosecond laser intrastromal ablation, and presbyopia-correcting IOLs can be very effective for improving near vision,” said Dr. Feinbaum, professor and clinical director, research professor of ophthalmology and optometry, Ben Gurion University of the Negev, Beersheba, Israel. “However, visual side effects can occur and may be intolerable for some patients, and reversibility of the cornea-based procedures has not been shown to date.
“Success with the topical pharmacological intervention depends on conducting a complete and careful examination to identify appropriate candidates,” Dr. Feinbaum continued. “For properly chosen presbyopes, however, it is a non-invasive, safe and easy modality for eliminating the use of glasses.”
Explaining the mechanism of action, Dr. Feinbaum said that the parasympathomimetic agent stimulates parasympathetic innervation-leading to accommodation-while the nonsteroidal anti-inflammatory drug prolongs the effect of the parasympathomimetic agent.
“The parasympathomimetic medication acts by stimulating the muscarinic receptor of the ciliary muscle and iris, while the NSAID inhibits prostaglandin production by the anterior uvea,” Dr. Feinbaum said. “The result is contraction of circular and transverse fibers of the ciliary muscle.
“The magnitude of the response depends on the quality and quantity of muscarinic receivers,” Dr. Feinbaum added. “The duration of effect can be up to 12 to 14 hours.”
Dr. Feinbaum noted that increasing DoF is an effective method for ameliorating the age-related reduction in amplitude of accommodation that causes presbyopia. As the pupil constricts, flat wavefronts change to spherical wavefronts, resulting in reduction of HOAs and correspondingly improved quality of vision.
“There are numerous HOAs, of which only spherical aberration, coma and trefoil are of clinical interest,” Dr. Feinbaum said. “Doubling of the pupil diameter increases spherical aberration 16-fold. Therefore, it is understandable that a small reduction in pupil size can result in a significant change in refraction.”
Patients are generally considered candidates for the pharmacological intervention if they have no more than 1.0 D of myopia, astigmatism, or hyperopia, and are free of corneal or vitreous opacities, retinal pathology, or chronic general pathology.
Patients with early cataract may also be considered candidates.
The 81 patients in Dr. Feinbaum’s study group ranged in age from 42 to 74 years with a mean of 52 years. Ten eyes were pseudophakic, 4 eyes had cataract, 10 eyes were postLASIK or PRK, and 57 were presbyopic without lens opacity. Spherical refraction for the group ranged from -0.75 D to +1.50 D and astigmatism ranged up to -1.75 D.
After treatment with 1 to 2 drops, mean pupil diameter decreased significantly from 3.77 mm to 2.63 mm and mean DOF increased significantly from 1.656 D to 2.596 D. Accompanying these changes, there were significant improvements in both mean UDVA (from 0.932 to 1.141) and UNVA (0.356 to 0.649).
“Subgroup analyses showed pseudophakic eyes had significant improvements in both near and distance UCVA, while presbyopic patients who were postrefractive surgery maintained 20/20 distance UCVA and had a significant improvement in UNVA from 0.4 to 0.7,” Dr. Feinbaum explained.
The drops were well-tolerated. Three-fourths of the patients experienced no adverse reaction. Four patients developed nausea immediately after instillation that quickly resolved, and 4 patients developed headache that gradually disappeared (duration 10-15 minutes).
Local adverse events included 2 cases each of dryness or burning, 4 cases of stinging, and 4 cases of blurry distance vision, all of which dissipated over 5 minutes.
“The oil-based formulation is usually helpful in people who have problems with dry eye,” Dr. Feinbaum noted.
Claes Feinbaum, MSc, PhD
This article is adapted from Dr. Feinbaum’s presentation at the 2015 meeting of the American Society of Cataract and Refractive Surgery. Dr. Feinbaum is one of the co-inventors of the product and is a board member of the FEPASAET Group. Dr. Feinbaum acts as a consultant for the ophthalmological industry for various companies.