Fig. 1 Top view imaging with Galilei G4
a: Four dots hair cross (first Purkinje reflex). b: Pupil
center (small white cross), angle kappa and chord mu data (Galilei G4
software).
Aberrometry assessment was performed with VX120 (Visionix, Inc.); this
is a multimodal platform, combining Scheimpflug and Placido-disc
technology, together with an Hartmann-Shack aberrometer which directly
measures corneal and total ocular aberrations, inferring the internal
aberrations from the aforementioned data. All measurements were
performed under the same illumination conditions (mesopic pupil at 5.5
lux).
Regarding distance measurement between protocol landmarks and reference
points, the authors have chosen a hybrid measuring method. For IOL
positioning assessment, eye photographs were obtained with Galilei G4 at
the protocol timepoint (36 months postoperatively) and subsequently
processed with the Fiji’s Image J program (software version
2.0.0-rc-49/1.51a), which allowed several measurements of the distance
between FPR, PC, OC and IOL center. Regarding IOL centration, the
postoperative first Purkinje reflex was defined as the reference point,
as it closely relates to the visual axis. Henceforth, decentration was
determined according to the measured distances between FPR and the IOL
centre (inner diffractive circle). Calibration was accomplished by using
the constant limbus horizontal size as a reference, allowing pixel
measurements conversion into millimetres for each eye.
Biometry was performed using optical interferometer Galilei G6 (Ziemer
Ophthalmic systems AG) and every subsidiary examination (such as OCT,
corneal topography, specular microscopy, etc.) was conducted by a
technician, unaware of the type of capsulotomy centration. Participants’
manifest refractions were collected (sphere, cylinder, and spherical
equivalent), with objective refractive errors assessed by an
autorefractor (Topcon Co. Ltd.).
Posterior capsule opacification was assessed at the 3 years
postoperative visit, after pupil dilation, with a modified version of
the Evaluation of Posterior Capsule Opacification (EPCO), as described
by some authors. For that matter, retroillumination images were obtained
with Visionix and subsequently processed with Image J, which allowed
identification, marking and calculation of density areas by performing
pixel counts. The density of the opacification behind the IOL was
clinically graded as follows: 0 = none; 1 = minimal; 2 = mild;
3=moderate; 4=severe. Then, individual PCO score for each eye was
determined with Evaluation of Posterior Capsule Opacification (EPCO) by
multiplying the density of the opacification (graded from 0 to 4) by the
fractional PCO area involved behind the IOL optic.
Patient reported outcomes were assessed using a 5-point Likert scale
questionnaire regarding the level of satisfaction (graded from 1 – very
dissatisfied; 2 – dissatisfied; 3 - neither satisfied nor dissatisfied;
4 - satisfied; 5 - very satisfied), whereas quality of vision was
determined by a 4-point Likert scale questionnaire comprising the
existence of visual disturbance or photic phenomena, graded from 0
(none) to 4 (very high).
Lens transparency was assessed by slitlamp examination and assigned a
grade according to the Lens Opacities Classification System (LOCS) III.
Corneal topography and tomography were determined using a Placido - dual
Scheimpflug device (Galilei G6). Macular spectral-domain optical
coherence tomography was performed with a modular ophthalmic imaging
platform (Carl Zeiss).
Postoperatively, all patients were evaluated at 1 day, 1 week, and at 1,
6, 12, 24 and every year thereafter and 36 months. Visual acuities were
assessed with Snellen chart (for distance) and reading Jaeger chart (for
near and for intermediate, with reading line conversion for the latest,
keeping the same visual angle) and ultimately converted to LogMAR
notation. Manifest refractions were collected (sphere, cylinder and
spherical equivalent), with objective refractive errors assessed by an
autorefractor (Topcon Co. Ltd.). At each visit, the uncorrected (UDVA)
and corrected (CDVA) distance visual acuities at 6 m, uncorrected (UIVA)
and corrected intermediate (CIVA) visual acuities at 60 cm, and
uncorrected (UNVA) and corrected (CNVA) near visual acuities at 40 cm
were measured. In the present study, and according to the proposed
protocol, only the long-term (at the 3-years’ visit) postoperative data
are presented. All patients filled in the quality of vision and
satisfaction level tests at 36 months.
Intraocular Lens
The AcrivaUD TrinovaTM (VSY
Technology) is a plate-haptic, diffractive aspheric hydrophobic acrylic
IOL with a blue light–filtering multifocal design. According to the
manufacturer, Sinusoidal Vision Technology (SVT®) has the aim of
reducing photic phenomena.