Retinal Nerve Fiber Layer and Macular Thickness Changes During Pregnancy

Study Overview
=================
Brief Summary
-----------------
Purpose: Primary: to prospectively measure Retinal Nerve Fiber Layer (RNFL) and macular thickness changes during pregnancy by Optical coherence tomography Secondary: The effect of pregnancy abnormalities on RNFL and macular thickness in participants who develop systemic or ocular complications during the study period.

Detailed Description
-----------------
There are several known ophthalmic physiologic changes in pregnancy: Refractive Change: progesterone-mediated changes in fluid content partially accounts for refractive change of lens and cornea; myopic shift of less than 1 D was observed in in 15% of participating pregnant women Night vision decreased mainly with low serum vitamin A levels in pregnant women. Fall of the IOP in second half of pregnancy (about 10% drop) Corneal changes (increased thickness; decreased sensitivity) = contact lens intolerance The retina and optic nerve are considered part of central nervous system, the retina and choroid are highly vascularized. Due to changes in CSF and brain volume, vascular and fluid changes all over the pregnant woman's body we expect to find changes in RNFL and macular thickness during pregnancy.

Official Title
-----------------
Retinal Nerve Fiber Layer and Macular Thickness Changes During Pregnancy by Optical Coherence Tomography: Prospective, Observational, Nonrandomized Controlled Study

Conditions
-----------------
Retinal Nerve Fiber Layer Thickness, Pregnancy, Macular Thickness

Participation Criteria
=================
Eligibility Criteria
-----------------
Inclusion Criteria: 1st trimester (6-14w) pregnant healthy women No known medical problems related to their current pregnancy on recruitment Age 18-45yrs No known retinal or optic nerve disease Refraction between +3.0 and -4.0 diopters Agrees to participate in the study Exclusion Criteria: Retinal or optic nerve disease Refractive errors more than +3.0 and -4.0. If already finished 14w gestation when recruited to the 1st OCT examination Known to have HTN or DM before gestation Ocular media abnormality that obscures OCT view or examination

Ages Eligible for Study
-----------------
Minimum Age: 18 Years
Maximum Age: 45 Years

Sexes Eligible for Study
-----------------
Female

Accepts Healthy Volunteers
-----------------
Accepts Healthy Volunteers

Study Plan
=================
How is the study designed?
-----------------
What is the study measuring?
-----------------
Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Retinal nerve fiber layer(RNFL) and Macular thickness by Optical coherence tomography(OCT) during pregnancy | The RNFL, measured in micrometers, will be followed up during the study. Every trimester (starting at the 1st trimester) an OCT will be performed measuring the thickness of the RNFL. An OCT will be performed 3 months postpartum as a control. The Macular thickness will be measured in the same manner. | 1 year | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Effect of systemic and ocular diseases on Retinal Fiber Layer and Macula during pregnancy | If systemic or ocular diseases appear during the study, they will be followed up and observed for changes in retinal fiber layer thickness and macular thickness. | 1 year |