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  5. FP84 : Reverse Geometry Corneal Reshaping – A New Paradigm in Myopia Management

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Dr. (Col.) Shrikant Waikar, W06753, Dr.Ashish Saksena

ABSTRACT

Reverse geometry corneal reshaping involves gentle compression of corneal epithelium with specially designed overnight wear lenses leading to a reversal of myopia. Being the first refractive interface of eye it leads to a maximum correction of myopia in a very short time . Acting on the continuously regenerating corneal epithelium it has no lasting undesirable side effects. It is especially suited for young children below 20 years of age where LASIK is contraindicated. It is ideal for young , budding, sportsmen particularly those indulging in contact sports for whom spectacles become a handicap . 278 eyes of 139 patients , undergoing myopia correction using reverse geometry corneal reshaping were followed up for over 2 years . Patients with myopia upto 2 D achieved a lens free interval upto 10 days ie they put on the lenses only thrice a month. Reverse geometry corneal reshaping was found to be safe and highly effective technique for correction of myopia and removal of glasses .

INTRODUCTION

Myopia is one of the commonest ocular refractive disorders known to mankind since time immemorial . The commonest treatment is prescription of corrective glasses. There has been a continuing quest towards removal of glasses. Various invasive and irreversible procedures are in practice mainly different forms of Laser procedures. These procedures are required to be performed once the progression of Myopia stabilizes. There is a need of a noninvasive and reversible procedure which can be performed when myopia is evolving that is even in younger age group.

Reverse geometry corneal reshaping , a form of overnight orthokeratology , is one such procedure which involves gentle compression of corneal epithelium with specially designed overnight wear lenses leading to a reversal of myopia [2,5]. These lenses are made of high oxygen transmission [Dk] material so  can be worn overnight [1-4]. Being the first refractive interface of eye it leads to a maximum correction of myopia in a very short time . Acting on the continuously regenerating corneal epithelium it has no lasting undesirable side effects. It is especially suited for young children below 20 years of age where LASIK is contraindicated. It is ideal for young , budding, sportsmen particularly those indulging in contact sports for whom spectacles become a handicap. This study was carried out to evaluate the efficacy of Reverse geometry corneal reshaping in effecting visual recovery and maintenance andlongevity of the visual recovery over a period of 2 years in patients with Myopia.

METHODS

278 eyes of 139 patients , undergoing myopia correction using reverse geometry corneal reshaping were followed up for over 2 years.All patients with myopia upto -5 D including Astigmatism up to – 2.5 D in the age group between 8yrs to 35 yrs were included. Patients with any ocular disease or any history of refractive surgical procedure or any other ocular surgery were excluded. All patients underwent a detailed ocular examination to satisfy the inclusion and exclusion criteria and to record various parameters. Reverse geometry corneal reshaping lens was selected and prescribed after a trial based on K reading . The patients were trained to put on and take off the lens on their own taking all the precautions. The regime was to wear the lens every night for 8 hours depending on the patient’s routine for 21 nights. After that the patients were encouraged to increase the lens free interval by skipping one night at a time.The patients were evaluated after the first and third overnight wear then at weekly intervals for 3 weeks. After that the patients werefollowed up at monthly intervals for 2 years . The unaided visual acuity was recorded. Objective and subjective refraction and slit lamp examination was carried out.

RESULTS

278 eyes of 139 patients , undergoing myopia correction using reverse geometry corneal reshaping were followed up for over 2 years .There were 48 patients in the age group of 8 to 12 years ,49 between 12 to 17 years and 42 above  17 years of age. There were 38 males and 101 female patients. All patients achieved a visual acuity of 6/6 after first overnight wear. After 21 nights of regular overnight wear 44 patients with myopia upto 2 D achieved a lens free interval upto 10 days ie they put on the lenses only thrice a month. 35 achieved a lens free interval of 9 days.  6 patients of Myopia between 2 to 3.5 D achieved a lens free interval of 7 days,  22 achieved a lens free interval of 5 days and 12 achieved 4 days. 11 patients upto – 5.00 D achieved a lens free interval of 2 days and 9 had to wear lens every alternate day.

DISCUSSION

Myopia has traditionally been treated  by prescription of corrective glasses. The continuing quest towards removal of glasses has led to various invasive procedures such as excimer laser photo refractive keratectomy or laser combined with surgery such as LASIK which permanently alters the structure of cornea.Intra ocular surgical procedures such as implantable contact lens (ICL), phakic intraocular lens or even clear lens extraction are also beingadvocated by some practitioners.These procedures are required to be performed once the progression of Myopia stabilizes.

The need of a noninvasive and reversible procedure which can be performed even when myopia is evolving that is even in younger age group, led us to evaluate reverse geometry corneal reshaping for its potential to correct myopia and ability to maintain the correction for maximum days.

Reverse geometry corneal reshaping , a form of overnight orthokeratology , is a procedure which involves gentle compression of corneal epithelium with specially designed overnight wear lenses leading to a reversal of myopia. Being the first refractive interface of eye it leads to a maximum correction of myopia in a very short time . Acting on the continuously regenerating corneal epithelium it has no lasting undesirable side effects.

278 eyes with Myopia upto 5 diopters on treatment with reverse geometry corneal reshaping were followed up for 2 years . All patients achieved a visual acuity of 6/6 after first overnight wear itself . After 21 nights the patients were encouraged to not to put on the lenses till the vision of 6/6 was maintained. The only side effect which was noticed in some patients was punctate staining of cornea after overnight wear for 21 nights . This resolved with artificial tears . Similar findings have been reported in literature [15]. 44 patients with myopia upto 2 D achieved a lens free interval upto 10 days ie they put on the lenses only thrice a month. 35 achieved a lens free interval of 9 days. So it was seen that all patients with myopia upto 2 diopters achieved a lens free interval of atleast 9 days. They had to put on the lenses for only 3 nights in a month which was highly convenient and the patients could remain glass free for full period of followup of 2 years. 6 patients of Myopia between 2 to 3.5 D achieved a lens free interval of 7 days,  22 achieved a lens free interval of 5 days and 12 achieved 4 days. These patients had to wear lenses once a week which was also easy to maintain the lens free interval for 2 years .11 patients upto – 5.00 D achieved a lens free interval of 2 days and 9 had to wear lens every alternate day. These patients were also quite motivated to wear the lenses to be able to remain lens or spectacle free during the day.

A number of studies are there which have studied the visual recovery using orthokeratology[6-9] and our results match with them. Reverse geometry corneal reshaping lens has been found to correct the myopia rapidly and it dramatically improves the unaided visual acuity with just one night of lens application [7,12-14].  However no study has documented the lens free interval using reverse geometry corneal reshaping and our study is the first one to do so. This is a very important aspect for the quality of life of the patient. This was also important as most of the patients were of younger age group and engaging themselves in games , contact sports and hobbies such as dancing where the spectacles were felt to be a handicap.These children adapted to the lens very easily and the visual recovery was 100% . Other studies also point to the fact that overnight orthokeratology is efficacious and safe for young myopic patients [10,11].Reverse geometry corneal reshaping  is especially suited for young children below 20 years of age where LASIK is contraindicated. It is ideal for young , budding, sportsmen particularly those indulging in contact sports for whom spectacles become a hindrance and a good natural vision without contact lens or glass is required.

TABLE-1 

Age distribution

S/no Age group Males (%) Females (%) Total
1. 8-12 14 (29%) 34 (71%) 48

 
2. 12-17 14 (28.5%) 35 (71.5%) 49

 
3. >17Yrs 10 (23.8%) 32 (76.2%) 42

 
Total 38 (27.3%) 101 (72.7%) 139

TABLE-2 

Sex distribution

S/no Sex Number

 
1. Male 38
2. Females 101

TABLE-3 

Degree of myopia vs

visual out come and

Lens free interval 

S/No Degree of myopia

(spherical equivalent)

 No of eyes Preorthokeratology

Visual acuity

 Postorthokeratology

Visual acuity   (After first overnight wear and  21 days)

 Lens free interval

(Days)
1. <-2.00 D 88

70

 6/12

6/18

 6/6

6/6

 10

9
2. -2.00 D to

-3.50 D

 12

44

24

 6/18

6/24

6/36

 6/6

6/6

6/6

 7

5

4
3. -3.50 D to

-5.00 D

 22

18

 6/36

3/60

 6/6

6/6

 2

1

Statistical Analysis paired t test P<0.001 highly significant.

REFERENCES

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  2. Swarbrick HA, Alharbi A. Overnight Orthokeratology induces central corneal epithelial thinning.Invest Ophthalmol Vis Sci 2001;42:S597.
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  10. WallineJJ,Rah MJ, Jones LA The children’s Overnight Orthokeratology Investigation (COOKI) pilot study. Optom Vis Sci.2004 Jun;81(6):407-13.
  11. Rah MJ, Jackson JM, Jones LA, MarsdemHJ,Bailey MD, Barr JT Overnight Orthokeratology: preliminary results of the Lenses and Overnight Orthokeratology (LOOK) study. Optom Vis Sc. 2002 Sep;79(9):598-605.
  12. Soni PS, Nguyen TT, Bonanno JA. Overnight orthokeratology: Visual and corneal changes, Eye contact lens 2003:29:137-145.
  13. Soni PS, Nguyen TT, Bonanno JA. Overnight orthokeratology: Refractive and corneal recovery following discontinuation of reverse geometry lenses. Eye contact lens 2004:30:254-262.
  14. Waikar S, Saksena A . Evaluation of Overnight Orthokeratology For Correction of Myopia IOSR-JDMS Volume 15, Issue 10 Ver. I (October. 2016), PP 52-56.
  15. Chan B,Cho P, Cheung SW. Orthokeratology practice in children in a university clinic in Hong Kong. ClinExpOptom. 2008 Sep;91(5):453-60. Epub 2008 Mar 18.         

 

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