High eye pressure is not the most common medical problem in scuba diving. But, there are several types of retinal complications that divers should know about.
The information in this guide explains the links between personal eye health and diving, with simplified answers to some common questions.
At sea level, human eyes adapt relatively well to the ambient pressure that surrounds them.
Even the combined weight of all the gases in the atmosphere has very little effect on the eyeball.
Here's the thing:
All scuba divers will be exposing their eyes to an increase of pressure as they descend from the surface.
In general, the negative effects on a diver's eyes will be little to none.
However, we should not ignore the fact that the resultant increased eye pressure in scuba diving may lead to some ophthalmological problems, including corneal irritation and ocular (eye) decompression sickness (DCS).
Suffering any acute eye disorder is likely to be painful. But, it's a sensitivity to light, diplopia, and decreased sight that means they are almost always contraindications for scuba diving.
There are several reasons for these symptoms, including trauma, inflammation, or ocular infection. In general, you should wait for the underlying acute condition to resolve before you return to diving.
(see further information below)
Scuba diving with poor eye health almost always risks further injuries. In particular, you should stay away from the water if an arterial gas embolism (AGE) or decompression sickness (DCS) is impairing your eyesight.
Sometimes, when vitreoretinal surgery is performed at the location of the vitreous and retina, it might leave a gas bubble in the eyeball.
When scuba diving under increased ambient pressure, it might result in intraocular barotrauma which can worsen your normal vision.
Polymethylmethacrylate orbital implants are used to replace eyeballs that have been surgically removed. Often, a traumatic injury, or disease, is the primary reason for having this kind of operation.
In most cases, these implants rule out scuba diving due to the increased pressures that divers encounter. In fact, the pressure can cause a hollow orbital implant to collapse.
If this happens, it can result in cosmetic problems and make it necessary to have further surgery (e.g. to replace damaged implants).
Pro Tip: Ocularplastic surgeons have started using hydroxyapatite implants instead. This porous material does not fall under scuba diving health and safety rules and is not a contraindication.
In general, scuba diving and visual acuity is somewhat of a personal judgement call (e.g. like driving a car). Thus, if your eyesight is good enough to meet driver licence regulations then it should be good enough to dive.
Likewise, unless your eyesight is good enough to meet driving licencing rules, you should get evaluated by an eye specialist about your fitness to dive.
Avoid scuba diving too soon after having any kind of eye surgery. Instead, wait for the recommended convalescent period for the particular procedure that you had.
The simple answer is yes. You can go diving even if you had surgery to replace the cloudy lens inside your eye with an artificial one.
In fact, nowadays it's rare to find a cataract surgeon that does not use the type of surgical incisions that offer peak postoperative wound strength.
Pro Tip: The type of surgery that you had will determine how long you'll need to wait before you go scuba diving after having your cataracts done.
In fact, diving with contact lenses has become much more common these days. But, it's best to get 'soft' contacts prescribed for you by an ophthalmologist (or optometrist).
There are two other types of contact lenses (e.g. the 'hard' lens type and the rigid gas-permeable). But, due to an inert gas load, these rigid types sometimes cause eye pain and blurred vision.
These symptoms can occur during or after a dive - because of the gas bubbles that form between the contact lens and the cornea.
One of the common causes of blurred vision after scuba diving occurs when contact lenses stick to the eye. Other factors may include:
Pro Tip: Check the lens is still in place before applying some lubricating eye drops.
What if you are experiencing some of these symptoms and you are not a contact lens wearer? Always seek medical attention if you are in any doubt. The Divers Alert Network (DAN) has a list of dive physicians - worldwide.
There are several reasons why you might have a bright red spot on an eyeball after making a scuba dive. But, the most common is subconjunctival haemorrhage. In a nutshell, there will be a collection of blood over the white part of the eye (sclera).
If it is the result of a 'mild squeeze' you shouldn't need any special treatment. But, having a severe mask squeeze may be an indication that you have other eye injuries.
Do not delay seeing an eye specialist if you have pain in any of your eyes, double vision, or blind spots in the field of vision.
Increased pressure inside the eye can damage the optic nerve and result in a loss of vision. Glaucoma is a disease associated with this problem. As a result, all glaucoma patients who want to go scuba diving should consider the following issues:
Pro Tip: Check with an ophthalmologist before scuba diving if you are taking medication for glaucoma or you had glaucoma surgery.
Despite being uncommon in itself, divers should be aware about the seriousness that having these symptoms may present, such as:
Do not delay seeking medical attention if you have any of these decompression sickness signs and symptoms after using scuba.
It's not uncommon for hyperbaric oxygen therapy to change the way the lens of the eye refracts light. It is a slow change and usually occurs after a few weeks of treatment.
Some patients may experience a slow myopic change (nearsightedness) when oxygen therapy continues for longer periods. In most cases, the change will revert back to normal after the treatment finishes.
RK is a surgical procedure for curing nearsightedness (myopia). The eye surgeon makes radially-oriented incisions in the cornea.
The result is a small decrease in cornea strength. Hence, subsequent barotraumas can increase the risk of serious injury - such as when scuba diving after radial keratotomy (RK).
But wait - there's more:
What if you had the new laser refractive surgery called photorefractive keratectomy? If so, yes you can dive. It is a new approach that uses laser reshaping of the cornea - not incisions.
Because this method doesn't decrease the cornea's structural integrity, you should be able to start diving after only a few weeks of having this surgery.
This guide focuses on personal eye health and associated restrictions for scuba diving. Yet, they do not apply in the same manner to hyperbaric oxygen (HBO) therapy.
An open source article titled 'Diving and hyperbaric ophthalmology' explains how hyperbaric exposures inside a dry chamber:
"Do not entail immersion of the eye or the possibility of facemask barotrauma. Only the presence of intraocular gas or hollow orbital implants remains as possible ocular contraindications to diving in these patients."
Important: The short tutorial video [4:01 seconds] presented by DAN explains how to avoid having a face squeeze with extra safety tips for new divers.