Transient photophobia is a common concern after cataract surgery, even in uneventful cases. We present a patient suffering from debilitating photophobia, who was successfully treated with bilateral implantation of a pinhole sulcus implant (Xtrafocus, Morcher).
A 49-year-old woman had undergone uneventful phacoemulsification surgery elsewhere with implantation of an Alcon Acrysof SN60WF IOL in both eyes, targeting emmetropia. Previously slightly myopic (−0.25 −0.5 × 30 in the right eye and −1 −0.25 × 65 in the left eye), she enjoyed full spectacle independence at intermediate and near ranges preoperatively.
She presented to us 10 months later with persistent photophobia requiring her to wear sunglasses under all circumstances outdoors, and often inside, despite different regimens of artificial tears and topical steroids. In addition, the patient expressed a profound disappointment with the sudden spectacle need for intermediate and near tasks.
Uncorrected visual acuity was 20/24 in both eyes, correcting to 20/20 in both eyes with a small hyperopic astigmatic correction (+0.5 −0.5 × 85 in the right eye and +0.75 −0.75 × 70 in the left eye). Biomicroscopic examination revealed a normal anterior segment with a stable tear film, without fluorescein staining of the cornea or conjunctiva. The IOL in both eyes was well-centered in the capsular bag. Minor glistenings of the hydrophobic material were noted but not considered visually significant and by no means excessive compared with ample previous experience with this IOL. A small-diameter Nd:YAG laser posterior capsulotomy, the temporal borders of which were visible in the pupil under photopic conditions, had already been performed.
The pupil diameter measured 4.7 mm in the right eye and 4.2 mm in the left eye under bright indoor light conditions (IOLMaster 700, Zeiss). Both pupils reacted briskly to slitlamp biomicroscopy, with no focal sphincter palsy. No iris transillumination defects were seen. Dilated fundoscopy was unremarkable.
The decision was made to enlarge both posterior capsulotomies to address possible straylight as the cause of photophobia with no effect.1 Subsequent in-office simulation of pseudophakic mini-monovision targeting −0.75 and −1.25 in either eye to address the concern of spectacle dependence only resulted in cross-blur and unsatisfactory intermediate vision. Given the chief concern of photophobia and, to a lesser extent, loss of depth of focus, the implantation of a pinhole implant in the sulcus of nondominant left eye first was discussed.2
Under topical and intracameral anesthesia, the anterior chamber was filled with cohesive ophthalmic viscosurgical device (Healon Pro), and the implant was delivered into the eye using an Alcon Monarch III loading system and D cartridge through a 2.2 mm temporal clear corneal incision. The haptics were tucked in the sulcus using a Lester hook. After removal of ophthalmic viscosurgical device with bimanual irrigation/aspiration, the pupil was constricted with intracameral carbachol (Miostat, Alcon), and 0.1 mL of cefuroxime (Aprokam, Thea Pharma) was injected into the anterior chamber.
Postoperatively, the patient noted immediate relief of photophobia, describing her visual experience as if she was wearing light sunglasses. Much to her satisfaction, she also noted crisp uncorrected distance vision (20/16) and reported marked improvement in performing visual tasks in the intermediate range without spectacles.
Goldmann kinetic perimetry showed comparably full peripheral visual fields for objects V4 and I4 in both eyes and concentric narrowing for the dimmer object I2 in the operated eye (Figure 1). After a thorough discussion of the unknown biological effects of bilateral implantation of this light-blocking device on circadian rhythm, the patient opted for an identical procedure on her dominant right eye 8 weeks later, with an equally satisfying result. During the 6-month follow-up, structural complications related to the device were not seen, and both implants remained well-centered (Figure 2).
To construct monocular and binocular defocus curves, the distance visual acuity of the patient was tested at 0.25 diopters (D) defocus intervals in the range of +2 to −3 D, on a standard high-contrast visual acuity chart (Nidek SC-1600) positioned at 6 m, at 200 cd/m2 brightness (Figure 3). Both eyes demonstrated a monocular visual acuity better than or equal to 20/25 over a 2.75 D range (+1.25 to −1.5).
The reduced retinal illuminance did not interfere to a great extent with daily life, although she admitted having slower dark adaptation than before and experiencing some difficulties navigating dark places. The patient was satisfied with the outcome.
The Morcher Xtrafocus intraocular implant was introduced with the primary aim of correcting corneal higher-order aberrations in pseudophakic patients.3 Secondary indications include near vision enhancement in monofocal pseudophakia and reduction of dysphotopsia in multifocal pseudophakia.2 The implant was made available in the European market in 2016 but is not available in the United States. The device is designed for sulcus placement with a 6 mm opaque optic incorporating a 1.3 mm aperture. Exploiting the pinhole effect, in a prospective study,3 significant improvements in visual acuity were achieved in eyes with irregular corneas due to keratoconus, penetrating keratoplasty, corneal laceration, and radial keratotomies.
To our knowledge, we are not aware of reports on the use of this intraocular device in eyes with optically regular corneas only to address photophobia and, less importantly, to extend depth of focus. The range of extension of depth of focus of 2.75 D with visual acuity better than or equal to 20/25 is in alignment with what can be mathematically achieved4 and with clinical results from a pinhole in-the-bag IOL (IC-8, Acufocus) targeted for slight myopia.5,6
The material of the pinhole device is fully opaque to wavelengths below 740 nm. Infrared light is transmitted, allowing fundus examination with the use of infrared cameras.2 Theoretically, the strongly reduced retinal illuminance of short-wavelength light in patients with bilateral implantation might interfere with normal circadian rhythms, and we have thoroughly informed our patient of this incertitude before addressing the second eye.7 After 6 month of follow-up, however, she has not experienced sleep difficulties or mood changes, and we will keep monitoring her over 6-month intervals.
Admittedly, blocking most incoming light, leaving only a fixed aperture of 1.3 mm, is a radical measure for pseudophakic photophobia, with undeniable visual sacrifices in mesopic and scotopic circumstances. Furthermore, similar to other authors,8 we also have personal experience in 1 patient who needed explantation of this device after posterior vitreous detachment with only minor vitreous floaters.
In retrospect, a preoperative trial of topical miotic agents might have been a more cautious initial approach to this case. Inducing miosis through a pharmacological route has the benefit of serving as a reversible proof of concept, before pursuing a surgical intervention. If well tolerated, the topical treatment can be continued on a daily or as-needed basis. Moreover, the number, timing, and concentration of applications can be tailored to the individual clinical response and visual needs, avoiding interference with mesopic and scotopic vision.
Instillation of brimonidine tartrate 0.2% (Alphagan, Allergan) eyedrops has been shown to induce clinically relevant miosis under scotopic luminance conditions.9 Its effect under photopic luminance conditions is minimal10 or absent,9 and its use in this case would not be advantageous. Furthermore, local intolerance and allergy are common.11 The widely used pilocarpine is a direct-acting muscarinic agonist with a dose-dependent effect.12 Concentrations as low as 0.125% can induce a measurable level of miosis in normal pupils.12 The tolerability of the common higher concentration 2% ophthalmic formulation is poor.13 A major inconvenience of blurred vision because of induced accommodation is obviously limited to the phakic eye. Brow ache, presumably arising from ciliary muscle spasm, local redness, and irritation are common causes of discontinuation of the drug.13
Despite the invasive nature of the treatment, we feel bilateral implantation of a pinhole sulcus device can be considered in highly selected patients with severe persistent photophobia after cataract surgery, only when all other causes are excluded or treated and only on the condition that patients are completely informed of the possible effect on circadian rhythm. Mental health and preexisting sleep patterns should be assessed preoperatively. In our experience, explantation of the sulcus-based device is straightforward. Should the need arise, the thin hydrophobic acrylic material is easily cut intraocularly and explanted through a small incision.
WHAT WAS KNOWN
- A pinhole sulcus implant improves visual acuity in selected cases of corneal irregularity.
WHAT THIS PAPER ADDS
- Bilateral implantation of a pinhole sulcus implant can be considered for intractable photophobia after cataract surgery.
- Despite the strong reduction of retinal illuminance, short-term follow-up has not shown detrimental effects on circadian functions in this patient.
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