Laser eye surgery glossary
P
Pachymetry
The process of measuring corneal thickness, usually using an ultrasonic probe. Further reading
Peripheral vision
The ability to see or be aware of objects and movement outside one's direct line of vision. Peripheral vision can be damaged by prolonged raised internal eye pressure (glaucoma). Further reading
Photo-ablation
The cold process of tissue removal which occurs with laser radiation. Ultraviolet light is so powerful that the molecular bonds of the target tissue are broken apart causing ablation. Microscopic pictures show incredibly precise cuts with no evidence of tissue burning in adjacent cells.
Photophobia
Light sensitivity. Further reading
Plano
No refractive error.
Presbyopia
The eye's gradually decreasing ability to focus on nearby objects. Presbyopia is a normal part of ageing and affects virtually everyone, usually becoming noticeable after age 40. People with presbyopia typically hold reading materials at arm's length in order to bring the words into focus. They may experience headaches or eyestrain while reading, viewing a computer screen, or doing close work. Presbyopia has been traditionally treated with reading glasses, bifocals, or contact lenses. PATIENTS WHO HAVE HAD LASER EYE SURGERY WILL STILL NOTICE THE EFFECTS OF PRESBYOPIA IN LAETR LIFE. But now there is CK (Conductive Keratoplasty), a minimally invasive eye surgery procedure developed specifically for presbyopic patients who only need near vision improvement. Further reading
PRK
The acronym for photorefractive keratotomy. A procedure involving the removal of the surface layer of the cornea (epithelium) by gentle scraping and use of a computer-controlled excimer laser to reshape the stroma. Further reading
PTK (Phototherapeutic Keratectomy)
The use of the Excimer laser to treat eye problems such as pronounced haze. Not laser eye surgery for short-sightedness. Further reading
Ptosis
The medical name for droopy eyelid. It can be a temporary side effect after laser eye surgery treatment. It is thought to be due to the 'eye clamp' pulling the eyelid muscles to hold the eye open. Is rarely permanent but can be surgically corrected if necessary. Further reading
Punctal occlusion
The punctum is the small hole on the lower eye-lid surface down which the tears drain away from the eye. In the case of quite severe eye dryness it is possible to block this hole with a small plug. This procedure is known as punctual occlusion.
Punctum
Tear drains located in the upper and lower eyelids in the corners of the eye lids towards the nose.
Pupil
The opening in the iris through which light passes so it may reach the retina. The pupil enlarges in dim light and closes in bright light. Further reading
