Deepa, M (2021) Posterior Segment Changes in Myopia: An Observational study. Masters thesis, Tirunelveli Medical College, Tirunelveli.
Full text not available from this repository.Abstract
INTRODUCTION: • Refractive errors are one of the preventable causes of blindness. • It accounts for a significant proportion of ocular morbidity. • Among which myopia accounts for a major percentage of it. • A previous study by the authors had reported a prevalence of only 13.1% among school children in India. • Myopia if not corrected at early stages can cause several retinal degeneration that can lead to irreversible blindness. • Excessive axial elongation of the eye in pathologic myopia results in mechanical stretching and thinning of the choroid and retinal pigment epithelium (RPE) layers, causing various degenerative changes in the retina. • This study is undertaken to analyse the various posterior segment degenerative changes in myopia which can lead to impaired visual acuity. AIM OF THE STUDY: 1. This study is intended to study the posterior segment changes of myopic patients. 2. The study is to analyse the co relation between the degree of myopia and the incidence of various posterior segment changes. MATERIALS AND METHODS: • This study is intended to include myopic patients of different age group who attend ophthalmology outpatient department(OPD) of Tirunelveli medical college. • The sample size is estimated to be around 100 subjects. INCLUSION CRITERIA: • Patients with myopic refractive error. • Patients in the age more than 5 years. EXCLUSION CRITERIA: • Subjects with index myopia (as seen in senile cataract). • Other ocular associations like microphthalmos, aniridia, megalocornea and congenital separation of retina. • Acquired causes of myopia such as post traumatic, post keratitic and drug induced. • Subjects with age <5 years who are not able to answer the Snellens visual acuity charting. STUDY DESIGN: • This is a prospective, observational case series of the subjects attending OPD. • Study duration 1 year 6 months. • The examination includes: 1. Visual acuity. 2. BCVA. 3. Axial length. 4. Fundus examination by: 1. Direct ophthalmoscopy. 2. Indirect ophthalmoscopy. 3. B-scan. 4. OCT. OBSERVATIONS: The posterior segment changes are studied based on • Age distribution. • Sex distribution. • Eye involved( unilateral or bilateral). • Incidence of various degenerative changes. DISCUSSION: 1. The study revealed that female showed increased prevalence of myopia 1.3 times more times than male. This is comparable to study of Arun Verma et al. 2. Family history is present in only 22% and absent in 88% of the subjects. 3. The prevalence of myopia was 95.6% bilateral and 4.4% unilateral in this study. 4. 80% of subjects had their uncorrected visual acuity between 1/60 and 6/60 of snellens visual acuity chart in both the eyes. 5. All patients belonging to low myopia category had their best corrected visual acuity improved to the category of 6/6 to 6/12 of snellen visual acuity chart. 6. 27% of subjects belonging to moderate myopia and 18% of subjects belonging to high myopia improved with refraction to the best corrected visual acuity category of 6/6 to 6/12 in right eye. 7. 25% of subjects belonging to moderate myopia and 16% of subjects belonging to high myopia improved with refraction to the best corrected visual acuity category of 6/6 to 6/12 in left eye. 8. Disc changes were more in both the eyes as the degree of myopia increases. 9. Among the disc changes, Peripapillary atrophy was the most common change followed by myopic crescent in both eyes. 10. Based on disc size comparison, 35% had large disc in right eye and 33% had large disc in left eye. 11. Among the posterior pole changes, tessellation was the most common change followed by Chorioretinal atrophy, followed by posterior staphyloma. 12. Based on Tokaro`s classification of CRA, patchy atrophy was predominant than diffuse atrophy. In the right eye, patchy atrophy was 64.86% and diffuse atrophy was 35.14%. In the left eye, patchy atrophy was 57.9% and diffuse atrophy was 42.1%. 13. Based on Steidl and Pruett`s classification of CRA, grade -0 CRA (no atrophic changes) was present in 63% in right eye and 60% in left eye. Next common occurrence is grade-2 CRA (Total area of CRA ≤ 2 optic disc areas) which is 24% in right eye and 22% in left eye. 14. Based on International Photographic Classification and Grading System for Myopic Maculopathy, category-0 (no macular lesions) was found in 23% in right eye and 25% in left eye. Out of which 13% and 15% belonged to low myopia category of right eye and left eye respectively. 15. Among the peripheral retinal changes, lattice degeneration is the most common manifestation noted in both the eyes accounting for 36% in both eyes. This is comparable to Celorio, Preutt R C. 16. Among the peripheral retinal changes, the second most common was retinal tear which was 5% in right eye and 3% in left eye. 17. In the left eye, 2% of subjects had retinal detachments along with retinal tear. 18. Posterior vitreous detachment is found in 33% of patients in right eye and 34% of patients in left eye. 19. Axial length > 30mm was observed in 6% of high myopes in right eye and 2% of high myopes in left eye. 20. Axial length > 26.5mm was observed in 43% of myopes in right eye and 33% of myopes in left eye. With the increase in axial length, the degree of myopia increases. This co relates with study of Liull et al. CONCLUSION: This study concludes that, • Females have increased prevalence of myopia than males. • Family history is not a significant co relation for myopia. • Almost all cases report with bilateral presentation of myopia. • With increase in degree of myopia, the visual acuity worsens. • The presence of posterior pole changes contributes to significant reduction in visual acuity. • The prolongation of axial length contributes to increase in degree of myopia and ocular morbidity.
| Item Type: | Thesis (Masters) |
|---|---|
| Additional Information: | 221813251 |
| Uncontrolled Keywords: | Posterior Segment Changes, Myopia, Observational study. |
| Subjects: | MEDICAL > Ophthalmology |
| Depositing User: | Subramani R |
| Date Deposited: | 11 Apr 2021 16:16 |
| Last Modified: | 11 Nov 2021 01:57 |
| URI: | http://repository-tnmgrmu.ac.in/id/eprint/14647 |
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