The Role of Atopy in the Choroidal Profile of Keratoconus Patients

Figures & data

Table 1 Inclusion and Exclusion Criteria

Inclusion Criteria

Patients diagnosed with KC (any stage)

Age between 14 and 30 years old

Continuous follow-up at the Corneal Department of CHUSJ

Exclusion Criteria

Existence of any ocular pathology other than KC

Eyes with other ocular surgeries besides intracorneal ring segments or crosslinking procedures (performed at least 6 months prior to the study)

Current treatment with any anti-inflammatory medication (systemic, ocular or topical) in the last month prior to the inclusion; only artificial tears were accepted

Any other systemic diseases rather than atopic conditions (AR, AD and/or AA)

Eyes with poor quality SD-OCT scans, where it is difficult to differentiate clearly the choroidal-scleral junction

Note: Inclusion and exclusion criteria used in the study.

Abbreviations: KC, keratoconus; SD-OCT, spectral-domain optical coherence tomography; CHUSJ, Centro Hospitalar e Universitário de São João; AR, allergic rhinitis; AD, atopic dermatitis; AA, allergic asthma.

Figure 1 Schematic representation of choroidal thickness measurement. Choroidal Thickness was measured from the outer edge of the hyperreflective line, corresponding to the retinal pigment epithelium, to the choroidal-scleral junction. Measurements were taken at the subfoveal choroid and at 500 µm intervals from the fovea: temporal 500 µm (T500), 1000 µm (T1000), 1500 µm (T1500) and nasal 500 µm (N500), 1000 µm (N1000) and 1500 µm (N1500).

Table 2 Summary of the Characteristics of the Patients’ Sample and Characterization of Tomographic Indices

	Mean (±SD)	Minimum	Maximum
Women, n	n=19, 24%
Right eye, n	n=68, 85%
Age, years	24.50 (4.40)	14	30
BCVA, decimal	0.79 (0.21)	0.10	1.00
Spherical equivalent, diopters	−2.35 (2.27)	−8.50	1.75
Kmax, diopters	56.72 (7.95)	42.10	82.10
Km, diopters	48.39 (5.37)	39.70	67.50
K2, diopters	50.05 (5.94)	40.60	71.40
PachyMin, um	457.15 (52.81)	262.00	555.00
D	9,54 (5.30)	0.13	30.35

Note: Results are expressed as mean ± SD (standard deviation) for continuous variables and female gender and right eyes expressed as count and percentage.

Abbreviations: BCVA, best corrected visual acuity; Kmax, maximum keratometry; Km, mean keratometry; K2, keratometry of the steepest meridian; PachyMin, minimum pachymetry; D, Belin/Ambrósio D-Index.

Table 3 Distribution of Atopic Conditions in Keratoconus Patients

	N	%
A Rhinitis	25	31%
Asthma	2	3%
A Dermatitis	7	9%
A Rhinitis + Asthma	6	8%
A Rhinitis + A Dermatitis	6	8%
Asthma + A Dermatitis	1	1%
A Rhinitis + Asthma + A Dermatitis	4	5%
None	29	36%

Abbreviations: n, number of patients; %, percentage.

Table 4 Characterization of Tomographic Indices in Atopic and Non-Atopic Groups

	Atopic	Non-Atopic	p
BCVA, decimal	0.80 (0.21)	0.77 (0,21)	p = 0.481
Spherical equivalent, diopters	−2.43 (2.36)	−2.19 (2.14)	p = 0.650
Kmax, diopters	56.97 (8.62)	65.28 (6.73)	p = 0.709
Km, diopters	48.67 (5.58)	47.88 (5.02)	p = 0.529
K2, diopters	50.37 (6.30)	49.48 (5.31)	p = 0.522
PachyMin, um	450.86 (48.82)	468.21 (58.43)	p = 0.159
D	9.71 (2.36)	9.23 (5.32)	p = 0.704

Note: Results are expressed as mean ± SD (standard deviation).

Abbreviations: BCVA, best corrected visual acuity; Kmax, maximum keratometry; Km, mean keratometry; K2, keratometry of the steepest meridian; PachyMin, minimum pachymetry; D, Belin/Ambrósio D-Index.

Figure 2 Boxplot results of each choroidal point analyzed in atopic and non-atopic groups. Results are expressed as median (± SD). Measurements undertaken at subfoveal (Fov), temporal 500 μm (T500), 1000 μm (T1000), 1500 μm (T1500), and nasal 500 μm (N500), 1000 μm (N1000), and 1500 μm (N1500). Atopic patients show thicker choroids in every analyzed point, although the differences are not statistically different.

Table 5 Multivariable Linear Regression Analysis

	Β Coefficient	95% Confidence Interval for β	p-value
Intercept	356,07	219.49 to 492.64	_
Atopy	55.14	1.859 to 108.43	0.043
Allergic Rhinitis	26.66	−23.785 to 77.18	0.296
Allergic Asthma	27.69	−29.71 to 85.09	0.335
Atopic Dermatitis	62.66	4.79 to 120.52	0.035

Notes: Multivariable linear regression analysis with an adjusted model for sex, age, spherical equivalent, history of medication and atopy, including subgroups (allergic rhinitis, allergic asthma and atopic dermatitis). Dependent variable: subfoveal choroidal thickness (CT), μm. Adjusted R² for the model was 2.9%.

Table 6 Subfoveal Choroidal Thickness According to Eye Rubbing Habits

Rubbing Habits	Mean	±SD	p
None	337.64	111.62	–
Rarely	379.81	104.33	p = 0.238 *
Sometimes	375.48	72.61	p = 0.283 *
Frequently	419.33	101.84	p = 0.004 *

Notes: *p value versus none rubbing habits. Values are expressed in µm.

Abbreviation: SD, standard deviation.