Eye measurements before lasik surgery: Pupil diameter, horizontal corneal diameter, length of eye ball and depth of front part of eye- Pre-LASIK tests no 4

In the earlier two blogs on pre-Lasik evaluation we discussed the importance of measuring corneal thickness and corneal topography prior to considering LASIK. In this blog we will understand the importance of some of the other measurements.

Suniti visited me at the Center for LASIK surgery at Advanced Eye Hospital and Institute in Navi Mumbai, India. She had got her LASIK laser vision correction done 2 years back in Mumbai. She had beautiful blue green eyes. She was getting troubled by the glare and haloes at night. Her power prior to the surgery was -4D. The power was not very high and by itself not enough to contribute to the glare problem at night. There can be several factors which contribute to night glare like large pupil (small round black front aperture which allows light to enter the eye) in dim light, dry eyes, presence of ocular aberrations and smaller zone of laser treatment. In her case there was a striking difference between the zone of her laser treatment on cornea and pupil size in the dim light conditions. Her pupil was quite big in dim light but her lasik laser had been done in a smaller area only in centre. When I explained the reason to her, on one hand she was reassured that there was no complication but on the other hand she was disturbed that why these measurements were not performed prior to the Lasik surgery. Irrespective of the type of laser vision correction procedure such as conventional Lasik or bladeless Femto LASIK or ReLEX SMILE Lasik, these measurements help plan the best type of LASIK surgery for the patient, understand the results, counsel the patients and set the expectations. Some measurements like pupil diameter, corneal diameter, eye ball length are a very important part of Pre-Lasik evaluation

1. Pupil Diameter– It is very important to know the pupil diameter in normal light conditions and in dim light conditions. Some people especially those with light colored eyes (iris) have large pupil in dim light conditions. If the zone of laser treatment during LASIK surgery is smaller than the scotopic (dim light) pupil diameter, then at night, light will enter the eye from 2 different zones. One from the laser treated zone on cornea and one from untreated cornea. This phenomenon leads to night vision issues like glare and halo etc. So knowing the pupil diameter is very important to plan the LASIK surgery better. Either we can plan the larger optical zone of laser treatment or we can chose other modes of treatment like smart aberration profile with larger transition zone or wave front guided treatment etc.

2. Corneal Diameter– This is measured to know the horizontal extent of the cornea (front transparent part of the eye). Laser vision correction procedure is done on cornea and it is the change in the corneal curvature which reduces the eye power. Corneal diameter helps us in making a decision about the size of the microkeratome suction ring in cases of conventional LASIK, or the size of the cup that we choose during bladeless femto lasik or ReLEx SMILE lasik. For example a smaller cornea will require a smaller ring and a smaller suction cup. Corneal diameter can be measured manually using manual or digital calipers or by the corneal topographer or the IOL master machine

3. Size of two eye balls– Ridhi is a Biomechanical engineer and lives in Mumbai. She wanted to get the best Lasik done. During her pre Lasik evaluation at the Center for LASIK surgery at Advanced Eye Hospital and Institute in Navi Mumbai, she took keen interest in all the tests and the machines that were used for those tests. When we were checking her eye ball length, she got very confused and enquired regarding the need for measuring the eye ball length before lasik. She asked “Isn’t the laser vision correction procedure performed on the cornea?”. I was very impressed by the depth of her thinking. She was absolutely right. It has no direct bearing on the Lasik surgery technique for most patients. But a few of us have very different eye powers in both the eyes. If the reason for different powers in both eyes is longer eye ball length in one eye then we may need to modify the planning for Lasik laser vision correction. Otherwise it can cause difference in image size between the two eyes after the laser vision correction procedure.

Length of the eye ball can be measured by either the eye ultrasound machine called A-scan or with the help of IOL master.

4. Depth of the Anterior chamber (front part of the eye) – Again this is one of those measurements which has no bearing on the laser vision correction procedure. However this is the measurement I need to know if I have to suggest an alternative procedure like ICL (Implantable contact lens) for someone who is not suitable for laser vision correction procedures. Rahul had come to the Center for LASIK surgery and had a power of -16D in both eyes. This much power cannot be safely corrected by even the best of the LASIK laser vision correction procedure. Luckily for him, the depth of the anterior chamber was 3.2mm. This was in the normal range and he successfully underwent ICL implantation in both the eyes and now enjoys a life free from glasses.

It is often said that we cannot plan if do not analyze and measure. This is no less true for pre Lasik evaluation. So even though the whole pre-Lasik evaluation takes up to 2 hour but it is required for proper planning, and better counseling, to get best Lasik surgery results and to ensure long term safety.

About Dr. Vandana Jain–

Dr. Vandana Jain

Dr Vandana Jain is an expert Cornea and Lasik surgeon. She has vast experience of performing laser vision correction procedures over a decade. She is well versed with all the latest techniques and advancements in laser vision correction procedures like LASIK, Femto Lasik, Smile Lasik, PRK etc. Dr. Jain ensures that all the patients undergo a detailed pre Lasik evaluation and then the best procedure and the technique is chosen for the patient to get satisfying results and to ensure long term safety.

About Center for Lasik Surgery at Advanced Eye Hospital and Institute, Navi Mumbai- Center for Lasik Surgery at Advanced Eye Hospital and Institute is one of the best lasik surgery centers, a modern well-equipped advanced center for all those who wish to get laser vision correction procedure done.  A very detailed protocol based and meticulous pre-Lasik evaluation is done for all the patients. The advanced equipments like corneal topographer, corneal tomographer, IOL Master, A scan, B scan and OCT machines help us in detailed measurements. The aim is to choose the best procedure for all the patients. AEHI caters to patients from all over Navi Mumbai such as Vashi, Nerul, Kharghar and Panvel besides people traveling from all over western India.

Watch Dr Vandana Jain, Cornea and Lasik Specialist perform SMILE Lasik – the most advanced and the best laser vision correction surgery in the world. Watch Dr Vandana Jain, Harvard trained Cornea & Lasik Surgeon at Advanced Eye Hospital and Institute (AEHI) in Navi Mumbai, India answer frequently asked questions on SMILE laser vision correction surgery

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Lasik and eye make-up- How soon and what kind of eye makeup can be done after Lasik

Use of make-up on the face and eyes is important to many of our patients. Their professional or personal demands impose on them this need and desire to apply make-up. During Lasik surgery we use laser to change the curvature of the cornea. Depending on the type of Lasik, the size of the cut on cornea can vary from 27-2mm. In conventional blade Lasik and the bladeless femto Lasik, a corneal flap is created in which the average circumference of the flap opening is around 27 mm.

Femto lasik
(Bladeless Lasik)

On the other hand in ReLEx Smile Lasik, no flap is created and the size of a small laser cut on cornea is only 2-4 mm.

SMILE Lasik
(Flapless, Bladeless Lasik)

These cuts have a healing and recovery period and it is important to not expose the eye to anything dirty during that period to reduce the risk of complications. It is a minimum of a week to two depending on the type of procedure. With Lasik and Femto Lasik it may vary from 2-3 weeks and after Smile Lasik one week is enough.

Smita, a resident of Vashi, is a model and she has to dress-up and apply heavy make-up on her face and eyes on a daily basis as a part of her work profile. She was declared suitable for Lasik after her detailed pre-Lasik evaluation at Centre for Lasik surgery at Advanced Eye Hospital and Institute in Sanpada, Navi Mumbai. Her first question was when she can start with her make-up again. Naturally for her it is a professional requirement. But for many others it could be just a personal desire or a party that they need to attend. I advised Smita to undergo Smile Lasik surgery. She was advised to wait for 7 days after her procedure for eye make-up. However we gave her a go ahead for face makeup after one day itself.

The reason we restrict the use of eye makeup after Lasik surgery is to protect anything dirty from entering the eye and to prevent eye infections. Lid infection can occur due to use of eye make-up and this in turn can lead to eye infection. Any form of eye infection can be damaging after Lasik surgery.

There are many dos and the don’ts related to eye make-up after Lasik surgery-

1. Avoid Eye make-up for one week after Lasik surgery

Even after one week, people need to be very careful. Be gentle as it is also possible for a mascara brush or eyeliner pencil to scratch or irritate your eyes. It is better to not use any eye makeup that could flake off in your eyes and cause irritation or give you the urge to rub your eyes. Flaky products include powder shadows with glitter or sparkle and mascaras that lengthen or strengthen lashes

2. Face make-up

It is fine to apply cream or make-up on the face away from the eye after 2-3 days. Again the precaution is to use non-powdery makeup on the face and keep all the products away from the eyes.

3. Throw all your old eye makeup and the applicators and buy new ones

The makeup and the brushes may contain bacteria, even after just a few previous uses and that can lead to an eye infection. Just washing the brushes and other applicators is not enough. If you need to apply make-up within a few weeks of LASIK then it is just better to use new eye make-up products and applicator brushes. This ensures safety and reduces the chances of eye infection.

4. Eye make-up removal needs to be very careful

A person after a Lasik surgery needs to be very careful while removing the eye make-up. It needs to be removed gingerly. No rubbing or excessive force should be applied. Any of the gentle eye make-up removers can be used or home based olive oil etc can be used. The aim is to not cause any flap displacement which can happen if excessive force is applied to remove eye make-up. This is what happened with Nina! Nina lives in Nerul and she had gone to attend a wedding 7 days after her Lasik surgery. She wore some shimmer eye shadow and was unable to remove it with her routine eye make-up remover. She tried to gently rub her eye lids to remove the eye make-up. But while she was doing it her son came running towards her and her finger hit her eye. She noticed blurring of vision and immediately came to the centre for Lasik surgery at Advanced Eye Hospital. Her flap had displaced due to the force of the finger. We quickly repositioned the flap and she was fine after that. Any excessive force on the eye within a few weeks of Lasik can lead to flap displacement and hence all care is needed.

No just after the Lasik; it is recommended that all traces of any make up, including lipstick and any facial lotions be completely removed even before the Lasik surgery. In order to make sure that no make is present during surgery, it is recommended to not wear makeup three days before Lasik surgery. So people like Smita who need to wear eye make-up as a part of the profession have to plan their Lasik surgery well. Eye make-up should not be done for almost ten days; starting 3 days prior to the surgery to one week after the Lasik surgery. Additionally ReLEx Smile is better in these cases as the size of incision on the cornea is just 2 mm and hence the risk of infection to the eye due to the use of eye make-up or face make-up is lesser. Also the risk of injury to the eye while applying or removing eye makeup is lesser as with Smile Lasik there is no flap on the cornea and hence there is no risk of flap displacement.

About Dr. Vandana Jain:

Dr Vandana Jain is a Cornea, cataract and Lasik surgeon. She has more than a decade of experience. She not only routinely performs Lasik for patients locally from Vashi, Nerul, Sanpada, Koperkhairne, Khargar and Panvel but also patients travel from all over Mumbai to get Lasik done by her. She is preferred by her colleagues for managing difficult and complicated cases. Doctors routinely prefer her for their own Lasik surgery

About Centre for Lasik Surgery at Advanced Eye Hospital and Institute at Sanpada, Navi Mumbai–

It is one of the most advanced and best centers for Lasik Surgery. It is equipped with the latest and complete set-up for pre-Lasik evaluation and all types of Lasik surgery. Wave front guided Lasik, Femto Lasik, ReLEx Smile Lasik, PRK, LasikXtra etc are all present under one roof. Patients from all over Mumbai and Navi Mumbai benefit from the services of the centre.

Videos

Watch Dr Vandana Jain, Cornea and Lasik Specialist perform SMILE Lasik – the most advanced and the best laser vision correction surgery in the world.

Watch Dr Vandana Jain, Harvard trained Cornea & Lasik Surgeon at Advanced Eye Hospital and Institute (AEHI) in Navi Mumbai, India answer frequently asked questions on SMILE laser vision correction surgery

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Eye Muscle testing before LASIK surgery- Diagnosing eye muscle weakness and Squint before laser vision correction: Pre LASIK Test No 3

Sofie got her LASIK surgery done 3 months ago in Dubai. She presented to the Center for Lasik Surgery at Advanced Eye Hospital and Institute in Navi Mumbai with complaints of headache and eye pain after working on computer for more than an hour. This was severely affecting her work efficiency and she was constantly troubled because of that. She was certain that her LASIK surgery led to some complications. We did a detailed eye evaluation for her. Her LASIK surgery had been done and had healed perfectly. However, on her eye muscle power checking, we found that she had severe convergence insufficiency. Basically the muscles in the eye which allow near work were weak. On closer questioning, she revealed that prior to getting her LASIK, she used to remove her glasses while working on the computer. The habit of removing glasses during near work caused her eye muscles to slowly develop weakness. When people like Sofie who have minus eye power do not wear glasses for near work, they are at risk of developing muscle weakness called convergence insufficiency. This can be missed before LASIK operation if muscle balance testing is not done prior to LASIK surgery as a part of pre LASIK evaluation. In patients like Sofie, eye muscle exercises can strengthen the muscles and then LASIK surgery can give best results without any muscle imbalance.

Just like Sofie there are a lot of us who have some or the other muscle imbalance or mild squint which needs to be detected prior to LASIK surgery. Eye Muscle balance, eye alignment and binocular function remains unchanged after LASIK laser surgery in most patients except those who have pre-existing muscle weakness, big difference in glass power between the two eyes and those with some post Lasik surgery factors like those where monovision surgery (one eye corrected for distance and one for near) is done.

A detailed muscle balance testing (orthoptic evaluation) goes a long way to detect those who are at risk of developing muscle balance related issues after different types of Lasik surgery like conventional Lasik, Bladeless Femto Lasik or ReLEx SMILE Lasik.

So, what are tests done during pre LASIK evaluation to detect muscle imbalance?

1. Accommodation– This is the ability of the eye to see near objects clearly. Usually the normal ability to accommodate reduces after the age of 40 and that’s when we need reading glasses to read near objects clearly. Occasionally young people may have accommodation abnormalities and may not see near objects clearly at the distance normal for their age. It is important to identify the type of problem and recommend exercises prior to going ahead with Lasik. This is to ensure best results and satisfaction after Lasik surgery.
2. Convergence– This is the ability to see near objects clearly without experiencing eye strain or doubling of objects at the right distance. Sometime a lot of people have convergence insufficiency which can get aggravated after LASIK. This is more likely to happen in those who wear thick glasses or those who do near work after removing their minus powered glasses. Thick glasses can sometimes mask the weakness due to minor prismatic effects.
3. Minor Squint– Sometimes people have an obvious or hidden squint. Leena had a type of squint called Intermittent Exotropia–a condition that would become obvious sometimes, specifically when she was tired. Usually it is possible to have LASIK in this condition if you are not wearing any prism correction in your eyeglasses. It is important for the LASIK Surgeon to perform muscle balance testing both with eyeglasses and contact lenses to see if the potential for the squint to worsen increases with contact lens wear. In another young woman, Lata, who had a power of -10D in her eyes, her squint was worsening when we checked her with contact lenses. This gave us the indication of what can happen to her squint after her LASIK laser surgery. Our squint surgeon decided to perform her squint surgery first. The recovery after the squint surgery was quick and she was back to work within a week. She got her bladeless Femto Lasik surgery done 3 months after her squint surgery. Today she is not just free from glasses but also free from her squint problem.
4. Fusional Amplitudes (Strength of eye muscles)- This test also gives us an indication of the muscle weakness and the possibility of squint development after Lasik surgery. If someone’s fusional amplitudes are poor it is better to give them eye exercises prior to considering their Lasik surgery.
5. Stereopsis (Depth Perception)-Vinod wanted to be a pilot in the armed forces and he wanted to get rid of his glasses for that. All the tests done for pre-Lasik evaluation were normal but his depth perception was abnormal. To ascertain the cause he was referred to our squint specialist. He was diagnosed to have microstrabismus. He was informed that he may not be able to clear the tests to be the fighter pilot as depth perception may be an important criteria for that! He still got his ReLEx Smile LASIK done and got rid of his glasses. Even though we could not treat his depth perception problem but at least he was aware! It can be disappointing if one realizes that later and not before their Lasik.

As LASIK surgeons we are glad that with all the advancements and newer best LASIK procedures like SMILE Lasik, we have the ability to reduce eye powers safely. For the best of Lasik surgeons, we desire is to treat your eyes holistically. Muscle imbalance or presence of squint needs to be evaluated as a part of pre LASIK evaluation. If required either muscle exercises or squint surgery needs to be planned either before or after laser vision correction procedure.

About Dr. Vandana Jain:

Dr. Vandana Jain- Lasik Surgeon

Dr Vandana Jain is an expert cornea and LASIK surgeon. She manages and treats patients from Mumbai, Navi Mumbai and all over Maharashtra who develop complications like infections etc due to contact lenses. Due to her dual expertise in cornea and LASIK, she is in a great position to decide and chose the right lasik procedure for these patients who develop corneal infections and then want freedom from glasses. She always cautions and educates her patients who are using contact lenses to maintain healthy contact lens care practices. Dr. Vandana Jain is a fellowship trained Cornea and LASIK surgeon. After having performed more than 5000 Lasik procedures, she is counted as one of the best Lasik surgeons in India. She believes in following a systematic scientific approach towards evaluating the patients for LASIK or Femto LASIK or the latest ReLEx Smile. She ensures that a detailed pre LASIK evaluation is done for all patients. According to her a detailed Orthoptic evaluation ensures that patients do not get eye fatigue or develop squint after their LASIK surgery.

About Center for LASIK surgery at Advanced Eye Hospital and Institute Navi Mumbai- Center for Lasik surgery at Advanced Eye Hospital and Institute is one of the most advanced centers for LASIK surgery in India. Proper protocols are followed for all the patients. A detailed pre LASIK evaluation is done with the help of all the advanced machines which are part of the center. A separate vision therapy and orthoptic clinic supports the orthoptic evaluation of all the patients prior to their LASIK. A squint surgeons consult is taken in all cases where any abnormality is detected. Patients from all over Navi Mumbai like Vashi, Kharghar, Nerul and Panvel visit AEHI for lasik evaluation and treatment.

Center for Lasik Surgery at Advanced Eye Hospital and Institute is a modern well equipped center for managing all kinds of complicated clinical situations. All the great diagnostic machines like corneal topography, corneal tomography, corneal pachymetry, OCT and IOL Master and associated clinics such as dry eye clinic and orthoptic clinic ensures a meticulous and protocol based pre Lasik evaluation. Besides this there are advanced machines for laser vision correction which allows all the different LASIK surgeries like wave front optimized LASIK, FemtoLasik, PRK, ReLEx SMILE and LasikXtra.

Videos

Watch Dr Vandana Jain, Cornea and Lasik Specialist perform SMILE Lasik – the most advanced and the best laser vision correction surgery in the world.

Watch Dr Vandana Jain, Harvard trained Cornea & Lasik Surgeon at Advanced Eye Hospital and Institute (AEHI) in Navi Mumbai, India answer frequently asked questions on SMILE laser vision correction surgery

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