SIST EN ISO 11979-10:2006
(Main)Ophthalmic implants - Intraocular lenses - Part 10: Phakic intraocular lenses (ISO 11979-10:2006)
Ophthalmic implants - Intraocular lenses - Part 10: Phakic intraocular lenses (ISO 11979-10:2006)
This part of ISO 11979 is applicable to any intraocular lens ( IOL) whose primary indication is the modification of the refractive power of a phakic eye, but excludes phakic IOLs (PIOLs) that utilize multifocal or other simultaneous vision optics to address presbyopic loss of accommodation and PIOLs that correct astigmatism. This part of ISO 11979 addresses specific requirements for PIOLs not addressed in the other parts of ISO 119 79.
Ophthalmische Implantate - Intraokularlinsen - Teil 10: Phake Intraokularlinsen (ISO 11979-10:2006)
Dieser Teil von ISO 11979 gilt für Intraokularlinsen (IOL), deren primäre Indikation die Modifikation der Brech¬kraft eines phaken Auges ist. Er gilt nicht für phake IOLs (PIOLs), die multifokale oder sonstige Optiken für das Simultan¬sehen zum Ausgleich eines presbyopen Akkomodationsverlustes einsetzen, sowie PIOL zur Korrektion von Astigmatismus.
Dieser Teil von ISO 11979 enthält besondere Anforderungen an PIOL, die in den übrigen Teilen von ISO 11979 nicht ent¬halten sind.
Implants ophtalmiques - Lentilles intraoculaires - Partie 10: Lentilles intraoculaires phaques (ISO 11979-10:2006)
L'ISO 11979-10:2006 s'applique à toute lentille intraoculaire (LIO), dont l'indication primaire est la modification de la puissance de réfraction d'un oeil phaque, mais exclut les LIO phaques (LIOP) qui utilisent des optiques multifocales ou à autre vision simultanée pour traiter la perte d'accommodation liée à la presbytie et les LIOP qui corrigent l'astigmatisme.
L'ISO 11979-10:2006 couvre les exigences spécifiques relatives aux LIOP qui ne sont pas abordées dans les autres parties de l'ISO 11979.
Očesni vsadki (implantati) - Intraokularne leče - 10. del: Intraokularne leče »phakic« (ISO 11979-10:2006)
General Information
Relations
Standards Content (Sample)
SLOVENSKI STANDARD
SIST EN ISO 11979-10:2006
01-oktober-2006
2þHVQLYVDGNL LPSODQWDWL ,QWUDRNXODUQHOHþHGHO ,QWUDRNXODUQHOHþH
ªSKDNLF© ,62
Ophthalmic implants - Intraocular lenses - Part 10: Phakic intraocular lenses (ISO 11979-
10:2006)
Ophthalmische Implantate - Intraokularlinsen - Teil 10: Phake Intraokularlinsen (ISO
11979-10:2006)
Implants ophtalmiques - Lentilles intraoculaires - Partie 10: Lentilles intraoculaires
phaques (ISO 11979-10:2006)
Ta slovenski standard je istoveten z: EN ISO 11979-10:2006
ICS:
11.040.70 Oftalmološka oprema Ophthalmic equipment
SIST EN ISO 11979-10:2006 en
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.
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SIST EN ISO 11979-10:2006
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SIST EN ISO 11979-10:2006
EUROPEAN STANDARD
EN ISO 11979-10
NORME EUROPÉENNE
EUROPÄISCHE NORM
August 2006
ICS 11.040.70
English Version
Ophthalmic implants - Intraocular lenses - Part 10: Phakic
intraocular lenses (ISO 11979-10:2006)
Implants ophtalmiques - Lentilles intraoculaires - Partie 10: Ophthalmische Implantate - Intraokularlinsen - Teil 10:
Lentilles intraoculaires phaques (ISO 11979-10:2006) Phake Intraokularlinsen (ISO 11979-10:2006)
This European Standard was approved by CEN on 7 August 2006.
CEN members are bound to comply with the CEN/CENELEC Internal Regulations which stipulate the conditions for giving this European
Standard the status of a national standard without any alteration. Up-to-date lists and bibliographical references concerning such national
standards may be obtained on application to the Central Secretariat or to any CEN member.
This European Standard exists in three official versions (English, French, German). A version in any other language made by translation
under the responsibility of a CEN member into its own language and notified to the Central Secretariat has the same status as the official
versions.
CEN members are the national standards bodies of Austria, Belgium, Cyprus, Czech Republic, Denmark, Estonia, Finland, France,
Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Romania,
Slovakia, Slovenia, Spain, Sweden, Switzerland and United Kingdom.
EUROPEAN COMMITTEE FOR STANDARDIZATION
COMITÉ EUROPÉEN DE NORMALISATION
EUROPÄISCHES KOMITEE FÜR NORMUNG
Management Centre: rue de Stassart, 36 B-1050 Brussels
© 2006 CEN All rights of exploitation in any form and by any means reserved Ref. No. EN ISO 11979-10:2006: E
worldwide for CEN national Members.
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SIST EN ISO 11979-10:2006
EN ISO 11979-10:2006 (E)
Foreword
This document (EN ISO 11979-10:2006) has been prepared by Technical Committee ISO/TC
172 "Optics and optical instruments" in collaboration with Technical Committee CEN/TC 170
"Ophthalmic optics", the secretariat of which is held by DIN.
This European Standard shall be given the status of a national standard, either by publication of
an identical text or by endorsement, at the latest by February 2007, and conflicting national
standards shall be withdrawn at the latest by February 2007.
According to the CEN/CENELEC Internal Regulations, the national standards organizations of
the following countries are bound to implement this European Standard: Austria, Belgium,
Cyprus, Czech Republic, Denmark, Estonia, Finland, France, Germany, Greece, Hungary,
Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland,
Portugal, Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland and United Kingdom.
Endorsement notice
The text of ISO 11979-10:2006 has been approved by CEN as EN ISO 11979-10:2006 without
any modifications.
2
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SIST EN ISO 11979-10:2006
INTERNATIONAL ISO
STANDARD 11979-10
First edition
2006-08-15
Ophthalmic implants — Intraocular
lenses —
Part 10:
Phakic intraocular lenses
Implants ophtalmiques — Lentilles intraoculaires —
Partie 10: Lentilles intraoculaires phaques
Reference number
ISO 11979-10:2006(E)
©
ISO 2006
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SIST EN ISO 11979-10:2006
ISO 11979-10:2006(E)
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Published in Switzerland
ii © ISO 2006 – All rights reserved
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SIST EN ISO 11979-10:2006
ISO 11979-10:2006(E)
Contents Page
Foreword. iv
1 Scope . 1
2 Normative references . 1
3 Terms and definitions. 1
4 Optical requirements. 1
4.1 General. 1
4.2 Dioptric power. 2
4.3 Imaging quality. 2
4.4 Spectral transmittance . 2
5 Mechanical requirements. 2
6 Clinical investigation. 2
6.1 General. 2
6.2 Clinical assessments. 2
6.3 Other considerations. 3
7 Information supplied by the manufacturer .4
Annex A (informative) Clinical investigation . 5
Annex B (informative) Statistical sample size considerations . 15
Bibliography . 18
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SIST EN ISO 11979-10:2006
ISO 11979-10:2006(E)
Foreword
ISO (the International Organization for Standardization) is a worldwide federation of national standards bodies
(ISO member bodies). The work of preparing International Standards is normally carried out through ISO
technical committees. Each member body interested in a subject for which a technical committee has been
established has the right to be represented on that committee. International organizations, governmental and
non-governmental, in liaison with ISO, also take part in the work. ISO collaborates closely with the
International Electrotechnical Commission (IEC) on all matters of electrotechnical standardization.
International Standards are drafted in accordance with the rules given in the ISO/IEC Directives, Part 2.
The main task of technical committees is to prepare International Standards. Draft International Standards
adopted by the technical committees are circulated to the member bodies for voting. Publication as an
International Standard requires approval by at least 75 % of the member bodies casting a vote.
Attention is drawn to the possibility that some of the elements of this document may be the subject of patent
rights. ISO shall not be held responsible for identifying any or all such patent rights.
ISO 11979-10 was prepared by Technical Committee ISO/TC 172, Optics and photonics, Subcommittee SC 7,
Ophthalmic optics and instruments.
ISO 11979 consists of the following parts, under the general title Ophthalmic implants — Intraocular lenses:
⎯ Part 1: Vocabulary
⎯ Part 2: Optical properties and test methods
⎯ Part 3: Mechanical properties and test methods
⎯ Part 4: Labelling and information
⎯ Part 5: Biocompatibility
⎯ Part 6: Shelf-life and transport stability
⎯ Part 7: Clinical investigations
⎯ Part 8: Fundamental requirements
⎯ Part 9: Multifocal intraocular lenses
⎯ Part 10: Phakic intraocular lenses
iv © ISO 2006 – All rights reserved
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SIST EN ISO 11979-10:2006
INTERNATIONAL STANDARD ISO 11979-10:2006(E)
Ophthalmic implants — Intraocular lenses —
Part 10:
Phakic intraocular lenses
1 Scope
This part of ISO 11979 is applicable to any intraocular lens (IOL) whose primary indication is the modification
of the refractive power of a phakic eye, but excludes phakic IOLs (PIOLs) that utilize multifocal or other
simultaneous vision optics to address presbyopic loss of accommodation and PIOLs that correct astigmatism.
This part of ISO 11979 addresses specific requirements for PIOLs not addressed in the other parts of
ISO 11979.
2 Normative references
The following referenced documents are indispensable for the application of this document. For dated
references, only the edition cited applies. For undated references, the latest edition of the referenced
document (including any amendments) applies.
ISO 11979-1, Ophthalmic implants — Intraocular lenses — Part 1: Vocabulary
ISO 11979-2, Ophthalmic implants — Intraocular lenses — Part 2: Optical properties and test methods
ISO 11979-3, Ophthalmic implants — Intraocular lenses — Part 3: Mechanical properties and test methods
ISO 11979-4, Ophthalmic implants — Intraocular lenses — Part 4: Labelling and information
ISO 14155-1, Clinical investigation of medical devices for human subjects — Part 1: General requirements
ISO 14155-2, Clinical investigation of medical devices for human subjects — Part 2: Clinical investigation
plans
3 Terms and definitions
For the purposes of this document, the terms and definitions given in ISO 11979-1, ISO 14155-1 and
ISO 14155-2 apply.
4 Optical requirements
4.1 General
This clause applies to the optical properties and performance requirements of PIOLs in their final form, as
intended for implantation in the human eye.
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SIST EN ISO 11979-10:2006
ISO 11979-10:2006(E)
4.2 Dioptric power
The requirements of ISO 11979-2 apply.
4.3 Imaging quality
The requirements of ISO 11979-2 apply.
NOTE A modified bench (e.g. additional converging lens, a microscope objective of appropriate numerical aperture,
etc.) can be needed to quantify the image quality of negative power PIOLs.
4.4 Spectral transmittance
The requirements of ISO 11979-2 apply.
5 Mechanical requirements
Where applicable to the PIOL design, the mechanical requirements given in ISO 11979-3 apply. Furthermore,
an analysis of the location of the PIOL surfaces with respect to ocular tissue shall be conducted to establish
the minimal anatomical dimensions acceptable for the design and the range of dioptric powers for which it
applies.
NOTE Guidance for performing this analysis is provided in ISO 11979-3.
6 Clinical investigation
6.1 General
The general requirements for a clinical investigation given in ISO 14155-1 and the clinical investigation plan
requirements in ISO 14155-2 apply. Additional requirements are given in 6.2 and in 6.3.
NOTE Annex A of this part of ISO 11979 contains suggested details concerning a clinical investigation.
6.2 Clinical assessments
The following assessments shall be considered for the clinical investigation plan:
a) visual acuity (VA);
b) refraction;
c) contrast sensitivity;
d) intraocular pressure;
e) corneal status;
f) iritis;
g) IOL decentration;
h) IOL tilt;
i) IOL discoloration;
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SIST EN ISO 11979-10:2006
ISO 11979-10:2006(E)
j) IOL opacity;
k) cystoid macular edema;
l) hypopyon;
m) endophthalmitis;
n) pupillary block;
o) retinal detachment;
p) status of crystalline lens;
q) status of anterior chamber angle;
r) status of iris;
s) pupil size;
t) corneal thickness.
6.3 Other considerations
To minimize the risks associated with the clinical investigation of a new PIOL, subject enrollment shall occur in
stages. The subject data from each stage shall be evaluated and found acceptable by the sponsor and the
principal investigator prior to the continuation of the clinical investigation. Guidance on phased enrollment is
included in Annex A.
Any plans for fellow eye implantation shall be described in the clinical investigation plan. Bilateral implantation
shall not be implemented until initial safety and performance data have been collected and evaluated by the
sponsor and the principal investigator.
The review of data from at least 50 eyes with six months of follow-up is recommended. Previous clinical
experience, i.e. results from well-documented clinical investigations, could be adequate justification to begin
bilateral implantation earlier in the study.
The clinical investigation plan shall contain descriptions of the surgical technique, the intraoperative use of
ophthalmic viscosurgical devices, and the use of preoperative, intraoperative and postoperative medications.
Any variations from these recommendations shall be recorded on the case report forms.
All subjects in a clinical investigation shall be monitored for the duration of the investigation. The clinical
investigation shall be considered completed when all subjects that have been enrolled in the investigation,
including subjects whose PIOL was removed or replaced, have reached the final reporting period.
Serious ophthalmic adverse events and all adverse device effects shall be reported using a special case
report form and forwarded to the sponsor for investigation. A drop in best spectacle corrected visual acuity of
two or more lines shall be considered a serious ophthalmic adverse event. All other ophthalmic adverse
events shall be reported using the standard visit case report forms and are collected during monitoring.
If a specific calculation procedure is to be used to determine the appropriate power for implantation, the
calculation procedure and its derivation shall also be included in the clinical investigation plan. Clinical data
shall be evaluated at intervals during the investigation to refine the power calculation procedure, if necessary.
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SIST EN ISO 11979-10:2006
ISO 11979-10:2006(E)
7 Information supplied by the manufacturer
The requirements of ISO 11979-4 apply, with the following additional information that shall be made available
to the user:
a) a summary of the results of the clinical investigation, if any;
b) any recommendations for periodic evaluations after implantation, based on the risk analysis and/ or any
clinical investigation performed;
c) any restrictions in the indications for use if necessitated by the anatomical clearance analysis and clinical
evaluation.
The general requirements for information provided by the manufacturer with medical devices specified in
[1]
EN 1041 should be considered. Symbols can be used instead of text, where appropriate. When symbols
[2] [3]
are used, the requirements of ISO 15223 and EN 980 should be considered.
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SIST EN ISO 11979-10:2006
ISO 11979-10:2006(E)
Annex A
(informative)
Clinical investigation
A.1 Objectives
The objectives of the clinical investigation are to determine the safety and performance of the PIOL.
A.2 Design
The type of clinical investigation recommended is a non-controlled study.
The clinical investigation plan should describe how subject visits in between reporting periods will be handled.
Each investigator should contribute a minimum of 20 subjects, but not more than 25 % of the subjects in the
study.
A minimum study duration of three years is recommended to adequately evaluate the maintenance of
endothelial cell density and the rate of cataract development. The clinical investigation plan should inform
subjects and investigators that longer term follow-up could be necessary.
[4]
Guidance for accountability is provided in ISO 11979-7 .
A.2.1 Primary endpoint
The recommended primary endpoint is endothelial cell density.
The null hypothesis is that the true rate of decrease in endothelial cell density is less than or equal to the
normal rate. The alternative hypothesis is that the true rate is greater than the normal rate. Sample size
guidance using this endpoint is provided in Annex B.
A.2.2 Inclusion and exclusion criteria
A.2.2.1 Inclusion criteria
The following inclusion criteria for subjects should be considered:
a) subject meets specified refractive criteria (spherical and cylindrical components);
b) subject has specified minimum best spectacle corrected visual acuity (BSCVA) in each eye;
c) subject has uncorrected visual acuity (UCVA) 0,5 or worse;
d) subject has less than 0,75 D difference between cycloplegic and manifest refractions;
e) subject has had a stable refraction (± 0,5 D; ± 1,0 D for high refractive errors), as expressed by manifest
refraction spherical equivalent (MRSE) for a minimum of 12 months prior to surgery, verified by
consecutive refractions and/or medical records or prescription history;
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SIST EN ISO 11979-10:2006
ISO 11979-10:2006(E)
f) subject who is a current contact lens wearer, needs to demonstrate a stable refraction (± 0,5 D),
expressed as MRSE, on two consecutive examination dates and stability of the refraction is determined
by the following criteria:
1) contact lenses were not worn for at least 2 weeks (rigid and toric contact lenses) or 3 days (soft
contact lenses) prior to the first refraction,
2) two refractions were performed at least 7 days apart;
g) subject, who is expected to have residual postoperative cylindrical refractive error of W 1 D, has been
given the opportunity to experience his/her best spectacle vision with the anticipated correction.
A.2.2.2 Exclusion criteria
The following exclusion criteria for subjects should be considered:
a) subject has an acute or chronic disease or illness that would increase the operative risk or confound the
outcome(s) of the study;
b) subject is taking systemic medications that can confound the outcome of the study or increase the risk to
the subject;
c) subject has ocular condition that can predispose for future complications;
d) subject has had previous intraocular or corneal surgery;
e) subject with less than the minimum endothelial cell density (ECD) at time of enrollment as described by
Table A.1;
f) subject with coefficient of variation of endothelial cell area W 0,45 (in both eyes);
g) subject is pregnant, plans to become pregnant, or is lactating during the course of the study, or has
another condition associated with the fluctuation of hormones that could lead to refractive changes;
h) monocular subjects;
i) insufficient space for the intended implant;
j) subjects that are not adults.
Table A.1 — Recommended minimum ECD
Age at time of enrollment Minimum endothelial cell density
2
years cells/mm
21 to 25 2 800
26 to 30 2 650
31 to 35 2 400
36 to 45 2 200
W 46 2 000
NOTE With the rate of endothelial cell density decrease unknown during the clinical
investigation, minimum endothelial cell density values were selected for this table that are
based on conservative assumptions in order to protect the subjects in the investigation. The
recommended endothelial cell density (ECD) in this table represents the average minimum
2
ECD necessary to leave 1 000 cells/mm at 72 years of age assuming a 10 % surgical
decrease and a yearly rate of decrease of 2 %.
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SIST EN ISO 11979-10:2006
ISO 11979-10:2006(E)
A.2.3 Enrollment of subjects
A.2.3.1 For clinical studies of a single refractive indication, the following phased enrollment plans are
recommended.
a) Phase I: 10 subjects, followed for 6 months.
b) Phase II: 100 additional subjects. A clinical evaluation of all available data is done when 50 subjects have
been followed for 6 months and all 110 subjects have been enrolled. If the performance of the PIOL is
acceptable, the sponsor can begin the last phase of the investigation.
c) Phase III: remainder of the subjects.
A.2.3.2 For clinical studies of more than one refractive indication ongoing simultaneously, the following
phased enrollment plans are recommended.
a) Phase I: 20 subjects (10 of each indication), followed for 6 months.
b) Phase II: 150 additional subjects (no more than 100 per indication). A clinical evaluation of all available
data is done when 50 subjects with one indication have been followed for 6 months. If the performance of
the PIOL is acceptable, the sponsor can begin the last phase of the investigation for that indication.
c) Phase III: remainder of the subjects for each indication.
A.2.3.3 Depending on the design of the refractive implant, a different phase-in can be appropriate. The
data from each stage is evaluated and found acceptable by the sponsor and the principal investigator prior to
proceeding to the next stage.
NOTE Previous clinical experience, i.e. results from well-documented clinical investigations, can be used as a
justification to support faster enrollment.
A.2.4 Examination schedule
The following reporting periods are recommended for postoperative examination (see Table A.2):
a) preoperative (Preop);
b) operative (Op);
c) Day 1 (1 day);
d) Week 1 (5 to 9 days);
e) Month 1 (3 to 5 weeks);
f) Month 3 (10 to 14 weeks);
g) Month 6 (21 to 26 weeks);
h) Month 12 (11 to 14 months);
i) Month 18 (17 to 21 months);
j) Month 24 (23 to 27 months);
k) Month 30 (29 to 33 months);
l) Month 36 (35 to 39 months).
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SIST EN ISO 11979-10:2006
ISO 11979-10:2006(E)
Table A.2 — Recommended postoperative examination schedule
Day Week Month Month Month Month Month Month Month Month
Study Preop Op
1 1 1 3 6 12 18 24 30 36
Distance UCVA X X X X X X X X X
Distance BSCVA X X X X X X X X
Near VA with X X X
distance spectacle
correction
a
Manifest refraction X X X X X X X X X
Cycloplegic X X X X X
refraction
Axial length X
b
Anterior chamber X X X
c
Intraocular pressure X X X X X X X X X X
d
Slit lamp exam. X X X X X X X X X
Status of crystalline X X X X X X X X
lens
Gonioscopic exam. X X X X X
Fundus exam. with X X X X X
dilated pupil
Mesopic pupil size X X X
e
Pachymetry of X X X X
corneal thickness
f
Keratometry X X X X
Subject X X X X X X X
questionnaire
g g
Specular microscopy X X X X X X X
Substudies
h
Contrast sensitivity X X X
i
Clearance analysis X X
Preop preoperative
Op operative
UCVA uncorrected visual acuity
BSCVA best spectacle corrected visual acuity
VA visual acuity
exam. examination
a
For contact lens wearers.
b
Distance from the posterior surface of the cornea to the anterior surface of the crystalline lens.
c
Post-surgery operative day IOP measurements are considered if pupillary block is a possible complication.
d
Tilt and decentration of the PIOL are included in the slit lamp assessment.
e
If required for the surgical procedure.
f
To establish preoperative refractive stability for contact lens wearers and to demonstrate postoperative corneal stability, where
necessary.
g
These evaluations are optional (in the case of specular microscopy data, they can be useful to demonstrate the trend associated
with the outcomes given the variability of the ECD measurements).
h
Contrast sensitivity testing is performed on all subjects preoperatively and repeated postoperatively on those subjects that are part
of the contrast sensitivity substudy and on all subjects that develop crystalline lens opacity at all remaining visits.
i
Methods such as ultrasonic biomicroscopy or Scheimpflug photography can be used.
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SIST EN ISO 11979-10:2006
ISO 11979-10:2006(E)
A.3 Evaluations
A.3.1 Visual acuity and refraction
Distance and near acuity charts, chart illumination, ambient illumination, testing distances and testing
procedures are standardized for all investigators. Reporting of refractions is standardized across study sites.
The design of the visual acuity chart and testing procedures with scoring methods are described by
[5]
Ferris et al. .
A.3.1.1 Luminance
2 2 2
Chart background luminance is 85 cd/m (80 cd/m to 160 cd/m is the acceptable range) for the photopic
testing. The chart background luminance is identical at all testing centres.
Ambient illumination is from dim to dark with no surface (including reflective surfaces) within the subject’s field
of view to exceed the chart background luminance.
A.3.1.2 Chart distance
For testing at a fixed distance, the chart distance should be precisely defined, no head movements relative to
the charts are allowed. For distance acuity testing, the best correction to the chart distance should be used
after adjusting the chart to optical infinity (e.g. + 0,25 D for a 4 m chart). When determining the best distance
refraction for treatment, however, the refraction should be adjusted to the refractive correction at infinity
(e.g − 0,25 D for a 4 m chart distance) if the chart is not at optical infinity.
A.3.1.3 Data recording procedures
Record all:
a) test distances;
b) refractive corrections;
c) measured visual acuities in log MAR notation, or other notation convertible to log MAR.
A.3.2 Specular microscopy
The main safety concern to be addressed by specular microscopy is the possibility of a progressive decrease
in endothelial cell density, which could lead to corneal decompensation.
Specular microscopy images are taken of the central cornea. Peripheral measurements are taken if warranted
by the design or placement of the PIOL. The peripheral locations to be photographed are specified based on
the design and/or placement of the implant.
To determine endothelial cell density decrease, specular microscopy is performed preoperatively and at 6, 12,
24, and 36 months. Given the variability of the measurements, consider performing the examination also at
18 and 30 months to increase the sensitivity of the trend analysis. Decreases due to surgical trauma can be
determined by evaluating the cell counts at Month 6 in comparison to the preoperative measurements.
To determine decreases over time, measurements from the 6 month examination and later time points are
analysed.
Operated fellow eyes with the experimental PIOL can be used in the endothelial cell density analysis after
correcting for the correlation between eyes. This can be accomplished in many statistical packages using the
general estimating equations method. The net effect of this technique is to adjust the standard errors (and
thus the confi
...
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