The preparation of patients for cataract surgery always require thorough examination on the part of the physician. The ophthalmologist has to come to a general understanding about the patient’s current visual and overall health condition. It also includes some investigations needed to determine the type of surgery to be done, and the refractive power of the IOL that will be implanted in the patient’s eye.
The ophthalmologist will then have a discussion with the patient to answer all his questions, address his fears, and make sure that the patient fully understands all aspects related to his condition prior to surgery. Please note that all this preparation only applies to patients who are already confirmed to undergo the surgery, and different from the pre-operative assessment.
Examination Of The Patient
This is divided into multiple steps including: testing and measurement of the visual function of both the cataractous eye and the sound eye, external examination of the patient, slit lamp examination of the eye, and finally fundus examination.
- Testing and measuring the visual function of the eye:
In order to accurately determine and document the state of the visual function of the eye prior to surgery, several aspects have to be assessed, including:
- Visual acuity testing for both eyes using Snellen’s chart in bright as well as dim light conditions for near and distance vision.
- Meticulous refraction must be done for both eyes as this helps in estimating the power of the IOL required to have the desired post-operative result.
- Brightness acuity testing using specific eye charts.
- Testing contrast sensitivity (Contrast sensitivity is the ability to detect subtle variations in shading).
- Confrontational visual field testing helps the ophthalmologist to determine the presence of ocular pathologies besides cataract. This is extremely important to be done in patients with history of glaucoma or retinal diseases so as to document the degree of visual loss before operation.
- External examination of the patient:
The importance of this examination is to identify the presence of any medical conditions that affect the external appearance or posture of the patient. Conditions like kyphosis, ankylosing spondylitis, or head tremors may affect the choice of the surgical approach and the method of anesthesia used.
- Slit lamp examination of the Eye:
This examination entails examination of different parts of the eye to exclude any ocular disease that may lead to postponing the surgery in order to treat that ocular disease first. On the other hand, the examination might lead to changing the surgery plan to fit the current condition of the patient’s eye, as for example shifting from doing phacoemulsification to extra capsular cataract extraction.
The examination includes examining the conjunctiva, cornea, anterior chamber depth and abnormalities, iris, and crystalline lens.
Examination of the lens allows the ophthalmologist to identify the type of cataract, and accurately estimate its density judging from the degree of lens opacity, and to learn about any abnormalities in the position of the lens in relation to other parts of eye.
Another part of the slit lamb examination is doing gonioscopy. By using this technique, the ophthalmologist is able to visualize a part of the eye called the filtration angle, which is the part of the eye responsible for draining the fluid that is continuously produced inside the eye (aqueous humor).
- Fundus examination of the eye:
This examination allows the ophthalmologist to visualize the retina of the patient in order to determine the presence of any abnormalities or disease. The presence of such conditions might have an impact on the final result of the surgery.
These measurements provide the ophthalmologist with important data needed for planning the type of surgery and calculating the power of the IOL to be implanted in the eye.
These include measuring the axial length of the eye to calculate the power of the IOL, examining the contour of the surface of the cornea, and measuring the corneal thickness.
Patient Counseling And Preparation Before Surgery
The aim of pre-operative counseling is to give the patient a general idea about his case and all the aspects related to the operation and post-operative period.
The ophthalmologist will discuss with the patient the indications for surgery in his case and other alternatives to surgery if applicable.
The ophthalmologist will highlight the presence of any medical conditions whether systemic or related to the eye that might have an impact on the final visual outcome of the operation.
He will also make sure that the patient has a clear understanding of possible surgical complications that might happen during or after the operation, as well as other serious vision threatening complications. He will mention what to do and what not to do in the period after the operation to ensure optimal healing and best visual outcome.
Finally, he will discuss with the patient how to use prescribed eye drops after the operation, as well as schedule appointments for follow up.