Disturbance in visual function can result from the hypoxia of altitude and the effects of cold.

High altitude eye problems: Disturbance in visual function can result from the hypoxia of altitude and the effects of cold. Hypoxia and a drying effect on the cornea from the increased evaporation of the tears,especially in windy conditions, can cause corneal swelling (edema). In normal eyes, this usually causes no visual disturbance though after corneal refractory surgery, refractory changes can occur. High altitude and hypoxia also affect the retina. Retinal hemorrhage is common but usually asymptomatic. However, if the macula is involved severe visual difficulties can occur.

UV Light could ruin your trip at high altitudes. Always wear protective gears.

UV‬ ‪light‬ problems: ‪‎Ultraviolet‬ light is a non-ionizing ‪‎radiation‬ and is divided into UV-A (315 to 400 nm), UV-B (280 to 314 nm), and UV-C (180 to 280 nm). The Earth’s atmosphere absorbs all UV-C radiation and more than 99% of UV-B radiation. It is known that the quantity of UV light increases with increasing altitude at a rate of 4% for each 300 m ascent), low latitude, and in highly ‪reflective‬ ‪environments‬. The reflection of ultraviolet increases two times from the surface of ‪water‬ and eight times from ‪snow‬ when compared to the reflection from a ‪‎field‬ ‪‎of‬ ‪grass‬ and it could damage to almost all ‪eye‬ ‪‎tissues‬ (eye ‪lids‬, ‪‎cornea‬, ‪‎conjunctiva‬ and ‪lens‬)

Heading to explore the mountains? Take utmost your eyes.

In the mountain or wilderness ‪environment‬, even minor ‪‎injuries‬ or ‪‎visual‬ ‪disturbance‬ could immobilize a person or make them dependent on others. This could precipitate other problems, such as a slow descent and unplanned bivouacs, thus putting the person and their party at risk. Although the eye surface area is less than 0.1 % of the total body surface, and therefore infrequently injured, eye injuries related to outdoor and ‪sport‬ activities in the mountains and wilderness areas are common. Most are minor eye injuries. However, unrecognized, or poorly treated, injuries can lead to a permanent and severe visual ‎impairment‬. In addition, many noxious factors in the environment are magnified in the mountains, and expose ‪‎mountaineers‬ and local inhabitants to an increased risk of eye problems.

High‬ ‪blood‬ ‪sugar‬ ‪levels should be regularly monitored during pregnancy.

‎High‬ ‪blood‬ ‪sugar‬ ‪levels‬ associated with ‪diabetes‬ can damage the small blood vessels that supply the ‪retina‬ of the ‪eye‬. The risk of damage goes up during pregnancy. A temporary form of diabetes that sometimes occurs during pregnancy, called ‪gestational‬ diabetes, can also cause blurred vision.

‪What‬ ‪to‬ ‪do‬: If you have diabetes, your condition should be closely monitored during pregnancy. If you develop gestational diabetes, your condition should be monitored to keep your blood sugar levels from climbing too high. Your ‪doctor‬ will help advise you.

Vision‬ ‪changes during pregnancy‬ can be a sign of preeclampsia

Preeclampsia‬ and Vision Problems
‪‎Vision‬ ‪changes‬ can be a sign of preeclampsia, a potentially serious problem that occurs in 5% to 8% of pregnancies. Preeclampsia is marked by high blood pressure and signs of damage to another organ. Vision changes typically include temporary ‪‎loss‬ of vision, ‪light‬ ‪sensitivity‬, ‪blurry‬ vision, ‪‎auras‬, and the appearance of ‪flashing‬ ‪‎lights‬.
 ‪‎What‬ ‪to‬ ‪‎do‬: If you experience any of these vision symptoms, call your ‪‎doctor‬ immediately or go to the emergency room. Preeclampsia can progress rapidly and cause bleeding problems and other serious complications.

Blurry ‪‎Vision During Pregnancy, is a side effect of pregnancy

Blurry ‪‎Vision During Pregnancy?

Fluid retention, a common side effect of pregnancy, can change the thickness and shape of the cornea. Minor changes in its shape may result in blurry or distorted vision. Fortunately, these changes usually go away after pregnancy or after you stop breast feeding.
What to do: You may not need to do anything if the changes don't bother you. If your vision alters significantly, however, talk to your doctor. You may need to change your prescription if you wear glasses. Most ‎eye ‪experts advise against getting ‪‎lasik ‪surgery or being fitted for new ‪‎contacts during pregnancy. The reason: the shape of your cornea will revert to normal after your pregnancy is over.

Dry eyes during Pregnancy

During pregnancy, women may notice that their eyes are drier than usual. ‪‎Dry‬ ‪eyes‬ can make wearing contacts irritating and uncomfortable.

‪What‬ ‪‎to‬ ‪‎do‬: Use artificial tears to lubricate the eyes and ease dryness. If the expecting mother wear contacts, then be sure to check the label to make sure the lubricant can be used with contacts. Ordinary artificial tears have preservatives that can harm soft contact lenses. Also, check with the doctor first to make sure the active ingredients are safe for pregnant women.