#198 - Eye health—everything you need to know | Steven Dell, M.D.
Dr. Steven Dell, an ophthalmologist and leader in refractive eye surgery, discusses eye anatomy, common vision issues like myopia and cataracts, and corrective treatments. He also provides essential strategies for protecting eye health and preventing vision loss, particularly in children.
Deep Dive Analysis
17 Topic Outline
Ophthalmology as a Specialty and Surgical Ergonomics
Basic Anatomy and Function of the Eye
Nearsightedness, Farsightedness, and Presbyopia Explained
Cataracts: Formation, Causes, and Surgical Repair
Pharmacological Pupil Manipulation for Vision Improvement
Evolutionary Reasons for Eye Color and Vision
Eye Trauma and Vision Enhancement Beyond 20/20
Astigmatism: Definition and Prevalence
Myopia Epidemic in Children: Causes and Prevention
Intraocular Lens Technology and Cataract Surgery Advances
Corneal Abrasions and Dry Eye: Causes and Management
Sunglasses and UV Protection for Eye Health
Laser Eye Surgery: PRK, LASIK, and SMILE Procedures
Glaucoma: Definition, Symptoms, and Treatment
Screen Time, Circadian Rhythm, and Eye Health
Contact Lens Hygiene and Risks
The Eye as a Window to Metabolic Health
9 Key Concepts
Nearsightedness (Myopia)
A condition where the eye is too long or the cornea is too steep, causing distant images to focus in front of the retina, making far objects blurry while near objects are clear. It is highly adaptive to environmental factors like near work and lack of outdoor light during development.
Farsightedness (Hyperopia)
A condition where the eye is too short or the cornea is too flat, causing distant images to focus behind the retina. Farsighted individuals may see far objects better, but near vision is often worse, and even far vision can be blurry.
Presbyopia
An age-related condition where the natural lens of the eye loses its elasticity, making it unable to change shape to focus on near objects. This typically begins around age 40 and is a universal component of aging, distinct from farsightedness.
Cataract
An age-related condition where the natural lens of the eye becomes stiff, hard, and loses its optical clarity, becoming opaque. It is a universal part of aging, though certain factors like trauma, diabetes, or steroid use can accelerate its formation.
Astigmatism
A common condition where the cornea (the front surface of the eye) is shaped more like an American football (oblong) instead of a basketball (spherical). This causes light to bend differently in various meridians, leading to distorted or blurry vision at all distances.
Wavefront Sensing
A technology used in laser eye surgery that digitally maps the entire optical pathway of the eye, from the retina to the front, to identify all distortions (nearsightedness, farsightedness, astigmatism, and other optical aberrations). This data is then used to customize the laser treatment for precise correction.
Photorefractive Keratectomy (PRK)
A type of laser eye surgery where the outermost layer of the cornea (epithelium) is removed, and an excimer laser directly reshapes the underlying corneal tissue to correct vision. The epithelium then regrows, leading to a longer visual recovery period compared to LASIK.
LASIK
A type of laser eye surgery where a thin flap is created on the cornea using a femtosecond laser, lifted, and then an excimer laser reshapes the underlying corneal tissue. The flap is then repositioned, allowing for much faster visual recovery than PRK, often achieving 20/20 vision by the next day.
Glaucoma
A group of about 100 different diseases that share the common pathway of damage to the optic nerve, typically related to pressure within the eye. It often affects peripheral vision first and has no symptoms until very late stages, making regular screening crucial.
9 Questions Answered
The eye is like a camera, with the cornea (front covering), pupil (hole in the iris), and lens at the front. Light is bent by the cornea and then the lens to focus on the retina at the back, which contains photoreceptors (rods for dim light/motion, cones for daytime/color vision) that convert light into electrical signals sent to the brain via the optic nerve.
New eye drops are being developed that can pharmacologically shrink the pupil to increase depth of focus, potentially allowing people with presbyopia to see up close again for 6-10 hours. Another experimental compound, a lipoic acid choline ester, is being studied to soften the lens, with the hope of delaying both presbyopia and cataract formation.
Different eye colors emerged as protection from UV and visible light, similar to skin tones. Darker eyes (more pigment) are typically found closer to the equator and offer greater protection to the retina's vascular supply from radiation, which can cause free radical formation. Lighter eyes have less pigment, making them more susceptible to UV damage and conditions like macular degeneration.
Myopia in children is driven by two main factors: deprivation from outdoor light and excessive near work (e.g., screens, books). The eye adapts by growing longer to focus on near objects. Spending at least 80 minutes outdoors daily, especially at noon, can cut the risk of nearsightedness in half, as bright light releases dopamine in the retina, which inhibits eye growth.
Modern cataract surgery involves removing the cloudy natural lens (leaving its outer capsule) and replacing it with an artificial, foldable plastic intraocular lens (IOL) through a tiny incision. This procedure not only restores clarity but can also correct existing vision problems like nearsightedness, farsightedness, astigmatism, and presbyopia, often leading to spectacle independence.
PRK involves removing the corneal epithelium and directly reshaping the cornea with a laser, leading to a longer recovery. LASIK creates a corneal flap, reshapes the underlying tissue, and then repositions the flap, resulting in faster recovery. SMILE uses a single femtosecond laser to create a lenticule (small piece of tissue) inside the cornea, which is then removed through a tiny incision, aiming for LASIK-like recovery with potentially less dry eye.
Dry eye has multiple causes, including medications, hormonal influences, autoimmune conditions, and meibomian gland dysfunction. Treatment strategies include artificial tears (eyedrops or mists), reducing bacterial counts at the lid margin (e.g., hypochlorous acid spray), and supplementing with omega-3 and certain omega-6 fatty acids (like GLA) for their anti-inflammatory effects.
Yes, adults should wear sunglasses to protect against UV light, which contributes to skin cancer on the eyelids, cataract formation, and age-related macular degeneration. The UV filter is crucial, not just the tint. Polarized lenses reduce glare (especially from water or highways) but offer no additional UV protection over non-polarized lenses with good UV filters, and can interfere with car displays.
The eye is a transparent organ, allowing direct visualization of brain tissue and the capillary network in the retina. Early signs of diabetic retinopathy, such as damaged capillaries, fluid exudation, hard exudates, and microaneurysms, can be observed. These findings can indicate uncontrolled diabetes even if A1C levels appear 'normal,' prompting further investigation of metabolic health.
11 Actionable Insights
1. Prevent Childhood Nearsightedness
Ensure children spend at least 80 minutes outdoors daily, especially during bright parts of the day, as outdoor light (specifically dopamine release from the retina) inhibits eye growth. Avoid prolonged indoor near-work in dimly lit rooms, which can increase nearsightedness risk 16-fold.
2. Protect Eyes from UV Light
Wear sunglasses consistently when outdoors, even on cloudy days, to protect against UV exposure. This helps reduce the incidence of skin cancer on the lower eyelid, delay cataract onset, and lower the risk of age-related macular degeneration. Focus on UV protection, not just tint, and be aware that car windows do not block all UV light.
3. Practice Safe Contact Lens Use
Prioritize wearing spectacles (glasses) as the safest option. If using contact lenses, avoid sleeping in them to prevent sight-threatening infections. If extended wear is unavoidable, ensure they are pristine, new pairs and remove them as quickly as possible.
4. Regular Glaucoma Screening
Undergo annual eye exams to screen for glaucoma, especially from age 50 onwards. These screenings check the appearance of the optic nerve and intraocular pressure, which are crucial for early detection and arresting disease progression before significant vision loss occurs.
5. Manage Dry Eye Symptoms
Use artificial tears as needed and consider supplementing with high doses of omega-3 fatty acids (e.g., 3 grams of EPA/DHA) and certain omega-6 fatty acids (e.g., GLA from blackcurrant seed oil) for their anti-inflammatory benefits. Address underlying causes like antihistamine use, hormonal imbalances (lack of testosterone), autoimmune conditions, or thyroid issues.
6. Mitigate Screen Blue Light
While screen blue light isn’t proven to damage eyes or cause macular degeneration, it can disrupt circadian rhythms. Use software like Flux on your devices to automatically reduce blue light emissions as the day progresses, especially in the evening, to support better sleep.
7. Ensure Eye Protection for Kids
Make sure children wear safety goggles when engaging in activities that pose a risk of eye trauma, such as cutting wood or smashing objects. Eye injuries are a leading cause of devastating visual loss in young people.
8. Wear Hats for Eye Protection
Supplement sunglass use with hats, as they provide additional protection by blocking some light that might otherwise bounce off surfaces and enter the eye.
9. Address Adult Nearsightedness Progression
Be aware that prolonged near-work, such as extensive reading for many hours a day (e.g., in graduate school), can contribute to the development or worsening of nearsightedness even in adulthood.
10. Consider AREDS Formula
If you have mild age-related macular degeneration, discuss with your doctor whether the AREDS formula (containing vitamins C, E, zinc, copper, lutein, and zeaxanthin) is appropriate, as studies show it can delay or reduce the conversion to severe disease.
11. Monitor Metabolic Health via Eye Exams
If you have diabetes, discuss with your endocrinologist any findings from your ophthalmologist regarding microvascular damage (e.g., fluid exudation, hard exudates, microaneurysms in the retina). These direct observations can indicate that your diabetes is not as well-controlled as blood tests like A1C might suggest, prompting further investigation and treatment.
5 Key Quotes
Valium is undefeated. It's just a question of how much.
Steven Dell
My vision is really important to me. I've got to see. I've got to see. And I get that. You know, it's, it's the one sense that if you asked people which sense they'd be most willing to give up or least, it's the very last.
Steven Dell
The worst thing you could do is stay inside in a dimly lit room and perform near tasks. That raises your risk of nearsightedness 16-fold compared to kids who go outside.
Steven Dell
It is our very strong clinical impression that omega-3s in high doses help with dry eye, primarily from, I think, an anti-inflammatory standpoint.
Steven Dell
The amount of blue light that you get from going outside is many, many, many orders of magnitude greater than what you can get from screens. But I do think that blue light can mess up your circadian rhythm.
Steven Dell