Ophthalmology is the branch of medicine and surgery which deals with the diagnosis and treatment of disorders and diseases related to the eye. It is a vast field covering various sub-specialties, each focusing on specific aspects of eye health and vision care. Here are some of the main subjects and topics typically covered in ophthalmology:

1. Anatomy and Physiology of the Eye: Understanding the structure and function of the eye, including the cornea, iris, lens, retina, optic nerve, and extraocular muscles.

2. Optics and Refraction: Study of light and its interaction with the eye, including concepts like refraction, accommodation, astigmatism, and presbyopia. This subject is crucial for diagnosing and correcting refractive errors through glasses, contact lenses, or refractive surgery.

3. Ophthalmic Pathology: Examination of diseases affecting the eye, including infections, inflammations, tumors, degenerations, and congenital abnormalities.

4. Ocular Pharmacology: Study of drugs used in the treatment of ocular conditions, including their mechanisms of action, indications, contraindications, side effects, and interactions.

5. Ophthalmic Surgery: Various surgical techniques used to treat eye conditions, such as cataract surgery, corneal transplantation, glaucoma surgery, vitreo-retinal surgery, refractive surgery (e.g., LASIK, PRK), and oculoplastic surgery (e.g., eyelid surgery).

6. Pediatric Ophthalmology and Strabismus: Diagnosis and management of eye disorders in children, including amblyopia (lazy eye), strabismus (misalignment of the eyes), congenital cataracts, and genetic eye diseases.

7. Neuro-Ophthalmology: Study of the relationship between the eyes and the brain, including conditions affecting the optic nerve, visual pathways, and eye movements. This includes disorders like optic neuritis, optic nerve tumors, and stroke-related visual disturbances.

8. Retina and Vitreous Diseases: Diagnosis and treatment of conditions affecting the retina and vitreous, including age-related macular degeneration, diabetic retinopathy, retinal detachment, and macular holes.

9. Cornea and External Diseases: Evaluation and management of disorders affecting the cornea and external eye structures, such as corneal infections, dystrophies, keratoconus, and ocular surface diseases.

10. Glaucoma: Diagnosis and treatment of glaucoma, a group of progressive eye diseases characterized by optic nerve damage and visual field loss. This includes medical, laser, and surgical management of intraocular pressure.

11. Uveitis and Inflammatory Eye Diseases: Diagnosis and management of intraocular inflammation, including anterior, intermediate, posterior, and panuveitis, as well as associated systemic conditions.

12. Ocular Oncology: Evaluation and treatment of intraocular and periocular tumors, including retinoblastoma, melanoma, lymphoma, and metastatic lesions.

13. Refractive Surgery: Techniques for correcting refractive errors, such as myopia, hyperopia, and astigmatism, to reduce or eliminate the need for glasses or contact lenses.

14. Low Vision and Rehabilitation: Strategies and devices to help individuals with impaired vision maximize their remaining vision and function effectively in daily activities.

15. Ethics and Professionalism in Ophthalmology: Understanding ethical principles, patient confidentiality, informed consent, and professional conduct in clinical practice.

These subjects encompass the breadth of knowledge and skills required for a comprehensive understanding and practice of ophthalmology. Ophthalmologists often continue to learn and specialize further within these areas throughout their careers.