Prospective evaluation of a novel silicone corneal shield after PRK: 6-month efficacy, safety, and predictability outcomes

Christopher S Sáles, Edward E Manche, Christopher S Sáles, Edward E Manche

Abstract

Purpose: The aim of this study was to report the 1-week and 6-month refractive outcomes of eyes treated with a novel silicone corneal shield designed to improve visual recovery after photorefractive keratectomy (PRK).

Patients and methods: This prospective, observational clinical trial recruited 45 myopic eyes with or without astigmatism at a university eye clinic to undergo wavefront-guided PRK followed by application of an investigational silicone corneal shield that was removed on postoperative day 4. The primary outcome measures were efficacy, predictability, and safety at the 6-month visit. The secondary end points included short-term uncorrected distance visual acuity (UDVA) and pain.

Results: No adverse outcomes occurred using the device. At 6 months, 79.5% of eyes achieved UDVA >20/20, 94.9% achieved ≥20/25, and 97.4% achieved ≥20/40. Also, 2.6% lost one line of corrected distance visual acuity and none lost two lines; 71.8% and 97.4% measured within ±0.25 and ±0.50 D of emmetropia, respectively. During the first week, preoperative UDVA improved from 1.34 logarithm of the minimum angle of resolution (logMAR; <20/400 Snellen) to 0.14 logMAR (>20/30) on postoperative day 1 (P<0.0001) and remained stable on days 2-3 (all P>0.05). After removal of the shield on day 4, UDVA declined by two lines before rebounding to 0.16 logMAR (>20/30) on day 7 (both P<0.001). Subjective metrics of pain all peaked between days 2 and 3 before declining.

Conclusion: The investigational silicone corneal shield is safe and effective when used after PRK and may aid early visual recovery and patient comfort, but comparative studies are needed to validate these preliminary findings.

Precis: One-week and 6-month refractive outcomes of a novel silicone corneal shield used after PRK show that the device is not only safe and effective but may also speed visual recovery.

Keywords: PRK; contact lens; safety; wound healing.

Conflict of interest statement

Disclosure EEM reports: equity in Calhoun Vision, Inc., Seros Medical, LLC, and Veralas, Inc.; serves as a consultant for Best Doctors, Gerson Lehrman, Abbott Medical Optics, and Avellino Laboratories; and conducts sponsored research for Abbott Medical Optics, Avellino Laboratories, and Presbia. The authors report no other conflicts of interest in this work.

Figures

Figure 1
Figure 1
Refractive outcomes after PRK using an investigational silicone corneal shield. Notes: (A) UDVA outcomes at 6 months. (B) Change in CDVA at 6 months. (C) Distribution of achieved spherical equivalent outcomes at 6 months. (D) Spherical equivalent refractive accuracy at 6 months. (E) Refractive astigmatism at 6 months. (F) Stability of spherical equivalent refraction between 3 and 6 months. Abbreviations: CDVA, corrected distance visual acuity; postop, postoperative; preop, preoperative; PRK, photorefractive keratectomy; UDVA, uncorrected distance visual acuity.
Figure 2
Figure 2
UDVA during the first postoperative week after PRK using an investigational silicone corneal shield. Note: The corneal shield was removed on day 4 at the onset of evaluation. Abbreviations: logMAR, logarithm of the minimum angle of resolution; PRK, photorefractive keratectomy; UDVA, uncorrected distance visual acuity.
Figure 3
Figure 3
Frequency of 20/25 and 20/40 UDVA during the first postoperative week after PRK using an investigational silicone corneal shield. Abbreviations: PRK, photorefractive keratectomy; UDVA, uncorrected distance visual acuity.
Figure 4
Figure 4
Pain, discomfort, light sensitivity indoors, light sensitivity outdoors, foreign body sensation, burning, tearing, heavy eyelid, and dryness as reported by the patient on an ordinal scale of 0–10 using a subjective questionnaire administered on days 1–7 and 30.
Figure 5
Figure 5
Photo of the investigational silicone corneal shield designed to improve uncorrected distance visual acuity in the immediate postoperative period after PRK. Notes: The NexisVision (Menlo Park, CA, USA) corneal shield is a bi-modulus silicone elastomer material designed to provide rapid visual and functional recovery to eyes treated with PRK. The lens has a thin, soft periphery and a thicker and slightly stiffer center optic designed to enable the patient to see well during the early postoperative period. Abbreviation: PRK, photorefractive keratectomy.

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Source: PubMed

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