CataractNCT00001613
Cataract Surgery to Obtain Human Lens Material for the Study of Nuclear Cataracts
An observational study of Cataract, run by National Eye Institute (NEI) at 1 site in United States.
Trial summary
Cataract, in which the lens of the eye is opacified, is the major cause of blindness. This study will examine protein material of the lens called crystallins to try to determine what causes nuclear cataracts, a type of cataract that forms in the central lens nucleus. Read more about this study
- Who is it for?
- Any ageHealthy volunteers can take part
- Conditions the study is for
- Cataract
- How many people
- 96 participants
- Where
- 1 siteUnited States
- Study dates
- May 1997to May 2002
- Phase
- Observational
- Are there results?
- None posted in the registry
Key requirements
Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.
- Ages Any age
- All sexes
- Healthy volunteers accepted
- Child, Adult, Older adult
Who may be able to join
- Patients with cataracts will be screened in order to determine eligibility.
- Patients 45 years and older of either sex with clinically significant cataract will be admitted to this study.
- Patients requiring cataract surgery should have either age related nuclear cataracts or cortical and/or posterior subcapsular cataract without nuclear cataract (controls).
- Age related nuclear cataract is defined using LOCS II Clinical Classification as having Nuclear color of 0-2, Nuclear Opalescence of 2-5, Cortical Opacity 0-1, and PSC 0-1.
- In addition, for controls, patients of either sex with clinically significant cortical or posterior subcapsular cataracts but having no nuclear cataract will also be recruited. These will have a LOCS grade of Nuclear Color 0-2, Nuclear Opalescence 0-1, Cortical 1-5, PSC 1.4.
Who cannot join
None listed.
Trial locations and contacts
1 site in 1 country.
United States1 site
National Eye Institute (NEI)
Bethesda, Maryland, 20892
About this study
Official title: Use of Human Lens Material for the Study of Nuclear Cataracts
Cataract, in which the lens of the eye is opacified, is the major cause of blindness. This study will examine protein material of the lens called crystallins to try to determine what causes nuclear cataracts, a type of cataract that forms in the central lens nucleus.
Men and women age 45 years or older with a cataract may be eligible for this study. Candidates will be screened to determine what type of cataract they have and will undergo a complete eye examination, including a vision test, eye pressure test, and examination of the lens and retina.
Read more
Patients selected for study will have a complete physical and eye examination, including photography of various parts of the eye, and ultrasound measurements of the eye. They will then have cataract surgery, either with or without intraocular lens implantation, and will have follow-up examinations 1 week, 3 weeks, 5 weeks and 8 weeks after surgery.
Tissue from the lenses removed during surgery will be given to NEI scientists for research on the causes of age-related nuclear cataracts.
Read the detailed description
Progress has been made in elucidating causative factors for some cataracts but little is yet known about those factors involved in development of aging-related nuclear cataracts. The predominant theory of nuclear cataractogenesis is that the lens crystallins accumulate covalent modifications which ultimately lead to increased light scattering. This theory is based on several lines of evidence. Crystallins, the predominant components of the lens, are present at very high concentration and determine the refractive properties of the lens. A relationship between crystallin alterations and cataract formation comes from studies on animal cataract models where mutations in crystallin genes have been identified. Numerous studies have also demonstrated that covalent modification of crystallins occurs in the human lens. These modifications are reported to be developmentally related, age related and/or the result of toxic environmental influences. Data from this lab demonstrated that the human lens crystallins undergo extensive covalent modification as part of normal lens fiber cell maturation. Crystallin modifications that cause cataracts would have to be superimposed on these normally occurring modifications.
We have begun a study under the protocol entitled "Use of Human Lens Material for Possible Causes of Cataract" to compare crystallins in nuclear cataracts with those in normal lenses. The goal was to identify uniquely altered crystallins, isolate the modified species and determine the covalent modifications that could possibly be involved in cataract formation. Surprisingly, our preliminary findings indicated that the pattern of protein spots on a 2-dimensional display of the total lens proteins (soluble, water insoluble and membrane) in the nuclear region of nuclear cataracts is essentially the same as found in the nucleus of normal lenses. Only the relative concentrations of these protein species varied. The number of pure nuclear cataracts available was too few 1) to determine the relationship between nuclear cataracts and crystallin covalent modification and 2) to establish the significance of concentration differences in crystallin species between normal lenses and nuclear cataracts. Therefore, the purpose of this protocol is to recruit enough subjects with pure nuclear cataracts to complete this study which should provide significant insights into the mechanisms underlying nuclear cataract.
- Conditions
- Cataract
- Keywords
- Cataract Surgery, Human Lens, Crystallins, Post-Translational, Protein Modification, Nuclear Cataract, Cataract Extraction
- Medical subject headings
- Cataract
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted4 Nov 1999 (estimated)
- Study startMay 1997
- Study completionMay 2002
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Publications (3)Papers the sponsor has linked to this study.
- Other trials for CataractStudies of the same condition, open and under way.
- What the trial phases meanHow a treatment moves from first tests in people to approval.
More details
For doctors and researchers: how the study is designed, who runs it, and its registry IDs.
Study design
- Study type
- Observational
- Enrolment
- 96 participants
Sponsor and investigators
- Lead sponsor
- National Eye Institute (NEI)
- Sponsor type
- US National Institutes of Health
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT00001613
- Sponsor's protocol ID
- 970121
- Other IDs
- 97-EI-0121
- Status last verified
- May 2002
- First submitted
- 3 Nov 1999
- Last updated
- 4 Mar 2008
- Results posted
- No
Publications
Datiles MB, Schumer DJ, Zigler JS Jr, Russell P, Anderson L, Garland D. Two-dimensional gel electrophoretic analysis of human lens proteins. Curr Eye Res. 1992 Jul;11(7):669-77. doi: 10.3109/02713689209000740.
PubMed 1521468Foster A, Johnson GJ. Magnitude and causes of blindness in the developing world. Int Ophthalmol. 1990 May;14(3):135-40. doi: 10.1007/BF00158310. No abstract available.
PubMed 2188914Dilley KJ. The proportion of protein from the normal and cataractous human lens which exists as high molecular weight aggregates in vitro. Exp Eye Res. 1975 Jan;20(1):73-8. doi: 10.1016/0014-4835(75)90109-8. No abstract available.
PubMed 1193192
Study at a glance
From the registry record, last updated by the sponsor on 4 Mar 2008. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- Use of Human Lens Material for the Study of Nuclear Cataracts
- ClinicalTrials.gov ID
- NCT00001613
- Acronym / sponsor ID
- 970121
- Conditions
- Cataract
- Keywords
- Cataract Surgery, Human Lens, Crystallins, Post-Translational, Protein Modification, Nuclear Cataract, Cataract Extraction
- Study type
- Observational
- Recruitment status
- Completed
- Enrolment
- 96 participants
- Lead sponsor
- National Eye Institute (NEI)US National Institutes of Health
- Study start
- May 1997
- Study completion
- May 2002
- First posted
- 4 Nov 1999 (estimated)
- Results
- Not posted in the source record
Clinical summary
The research question as the sponsor registered it. This describes what the study plans to test, not what it found.
Cataract, in which the lens of the eye is opacified, is the major cause of blindness. This study will examine protein material of the lens called crystallins to try to determine what causes nuclear cataracts, a type of cataract that forms in the central lens nucleus.
Men and women age 45 years or older with a cataract may be eligible for this study. Candidates will be screened to determine what type of cataract they have and will undergo a complete eye examination, including a vision test, eye pressure test, and examination of the lens and retina.
Patients selected for study will have a complete physical and eye examination, including photography of various parts of the eye, and ultrasound measurements of the eye. They will then have cataract surgery, either with or without intraocular lens implantation, and will have follow-up examinations 1 week, 3 weeks, 5 weeks and 8 weeks after surgery.
Tissue from the lenses removed during surgery will be given to NEI scientists for research on the causes of age-related nuclear cataracts.
Detailed description
Progress has been made in elucidating causative factors for some cataracts but little is yet known about those factors involved in development of aging-related nuclear cataracts. The predominant theory of nuclear cataractogenesis is that the lens crystallins accumulate covalent modifications which ultimately lead to increased light scattering. This theory is based on several lines of evidence. Crystallins, the predominant components of the lens, are present at very high concentration and determine the refractive properties of the lens. A relationship between crystallin alterations and cataract formation comes from studies on animal cataract models where mutations in crystallin genes have been identified. Numerous studies have also demonstrated that covalent modification of crystallins occurs in the human lens. These modifications are reported to be developmentally related, age related and/or the result of toxic environmental influences. Data from this lab demonstrated that the human lens crystallins undergo extensive covalent modification as part of normal lens fiber cell maturation. Crystallin modifications that cause cataracts would have to be superimposed on these normally occurring modifications.
We have begun a study under the protocol entitled "Use of Human Lens Material for Possible Causes of Cataract" to compare crystallins in nuclear cataracts with those in normal lenses. The goal was to identify uniquely altered crystallins, isolate the modified species and determine the covalent modifications that could possibly be involved in cataract formation. Surprisingly, our preliminary findings indicated that the pattern of protein spots on a 2-dimensional display of the total lens proteins (soluble, water insoluble and membrane) in the nuclear region of nuclear cataracts is essentially the same as found in the nucleus of normal lenses. Only the relative concentrations of these protein species varied. The number of pure nuclear cataracts available was too few 1) to determine the relationship between nuclear cataracts and crystallin covalent modification and 2) to establish the significance of concentration differences in crystallin species between normal lenses and nuclear cataracts. Therefore, the purpose of this protocol is to recruit enough subjects with pure nuclear cataracts to complete this study which should provide significant insights into the mechanisms underlying nuclear cataract.
Study design
Who may qualify
- Sex
- All
- Healthy volunteers
- Accepted
- Age groups
- Child, Adult, Older adult
Key inclusion criteria (5 listed)
- Patients with cataracts will be screened in order to determine eligibility.
- Patients 45 years and older of either sex with clinically significant cataract will be admitted to this study.
- Patients requiring cataract surgery should have either age related nuclear cataracts or cortical and/or posterior subcapsular cataract without nuclear cataract (controls).
- Age related nuclear cataract is defined using LOCS II Clinical Classification as having Nuclear color of 0-2, Nuclear Opalescence of 2-5, Cortical Opacity 0-1, and PSC 0-1.
- In addition, for controls, patients of either sex with clinically significant cortical or posterior subcapsular cataracts but having no nuclear cataract will also be recruited. These will have a LOCS grade of Nuclear Color 0-2, Nuclear Opalescence 0-1, Cortical 1-5, PSC 1.4.
Key exclusion criteria (0 listed)
Eligibility is decided by the study team after screening; this overview does not establish that a patient qualifies. Full inclusion and exclusion criteria.
Primary outcome
Not reported in the source record.
Results and safety
The study is completed, but results are not available in the source record. That does not mean the treatment did or did not work.
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 4 Mar 2008.
- Background: PubMed 1521468Datiles MB, Schumer DJ, Zigler JS Jr, Russell P, Anderson L, Garland D. Two-dimensional gel electrophoretic analysis of human lens proteins. Curr Eye Res. 1992 Jul;11(7):669-77. doi: 10.3109/02713689209000740.
- Background: PubMed 2188914Foster A, Johnson GJ. Magnitude and causes of blindness in the developing world. Int Ophthalmol. 1990 May;14(3):135-40. doi: 10.1007/BF00158310. No abstract available.
- Background: PubMed 1193192Dilley KJ. The proportion of protein from the normal and cataractous human lens which exists as high molecular weight aggregates in vitro. Exp Eye Res. 1975 Jan;20(1):73-8. doi: 10.1016/0014-4835(75)90109-8. No abstract available.
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Referral and contact
AzTrials does not enrol participants or take referrals. Contact the study team or a site listed below; they decide who can take part. This study is not recruiting at the moment.
The record lists no contact. Use the official record to reach the sponsor.
1 site in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
An observational study of Cataract, run by National Eye Institute (NEI) at 1 site in United States.
The full registered description is in the About this study section and the official record.
Who may be eligible to take part?
The sponsor lists 5 inclusion and 0 exclusion criteria. Eligibility is decided by the study team after screening, so read the full criteria and contact a listed site.
Is this clinical trial currently recruiting?
The record says: finished, as of the sponsor's last update on 4 Mar 2008. Status can change between updates, so confirm with the study contact before making plans.
Where is the study taking place?
The record lists 1 site in United States. Whether a site is taking part right now should be confirmed with that site. See every site.
What are the possible benefits and risks?
They depend on the study and the treatment, and no study can promise a benefit. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.
Are results available for this study?
The study is completed, but results are not available in the source record. That does not mean the treatment did or did not work.
How can a doctor refer a patient or contact the research team?
The record lists no contact. The official record names the sponsor, who can be asked directly. AzTrials does not enrol participants or take referrals.
Where can I read the original study information?
On the ClinicalTrials.gov record for NCT00001613, which also lists 3 linked publications.
Does a listing mean the treatment is approved or proven to work?
No. A listing means the study is registered. It does not show that the treatment is safe, works, or is approved by a regulator.
How often is this information updated?
AzTrials copies changed records from ClinicalTrials.gov every night and reloads the whole registry every week. The sponsor last updated this record on 4 Mar 2008.